Mississippi river

In the summer of 1903 the late Richard B. Dole, chemist of the water-resources branch of the United States Geological Survey, began a systematic investigation of the composition of the river and lake waters of the United States. His plan, which developed gradually, was to have analyses made of the different waters in such a manner as to give the average composition of each one for an entire year. For a few waters, such completeness was impracticable, the analyses covered only part of a year, but even in these waters the data obtained were of much value. As a rule, samples of each water were collected day by day. They were then mixed in sets of ten and analyzed, so that for each river or lake from 34 to 37 analyses were made. For the Mississippi above New Orleans composite analyses were made in sets of seven, giving 52 analyses from which to compute the average. For the Great Lakes, however, only monthly samples were taken, for the reason that their waters vary so little in composition that greater elaboration was not necessary. Some of the larger rivers were treated even more thoroughly; their average composition was determined at more than one point – the Mississippi at six points. For some rivers the analyses cover two years of collection, and for the data, received from a contributor not connected with the Geological Survey, three years.

@article{doi103133pp135,
    author = "Clarke, F. W.",
    title = "The composition of the river and lake waters of the United States",
    year = "1924",
    journal = "USGS professional paper",
    abstract = "In the summer of 1903 the late Richard B. Dole, chemist of the water-resources branch of the United States Geological Survey, began a systematic investigation of the composition of the river and lake waters of the United States. His plan, which developed gradually, was to have analyses made of the different waters in such a manner as to give the average composition of each one for an entire year. For a few waters, such completeness was impracticable, the analyses covered only part of a year, but even in these waters the data obtained were of much value. As a rule, samples of each water were collected day by day. They were then mixed in sets of ten and analyzed, so that for each river or lake from 34 to 37 analyses were made. For the Mississippi above New Orleans composite analyses were made in sets of seven, giving 52 analyses from which to compute the average. For the Great Lakes, however, only monthly samples were taken, for the reason that their waters vary so little in composition that greater elaboration was not necessary. Some of the larger rivers were treated even more thoroughly; their average composition was determined at more than one point – the Mississippi at six points. For some rivers the analyses cover two years of collection, and for the data, received from a contributor not connected with the Geological Survey, three years.",
    url = "https://doi.org/10.3133/pp135",
    doi = "10.3133/pp135",
    openalex = "W1576121576"
}

@techreport{trowbridge1930building6,
    author = "Trowbridge, A. C",
    title = "Building of the Mississippi delta",
    year = "1930",
    howpublished = "Bulletin of the American Association of Petroleum Geologists, v. 38, p. 167-192",
    note = "talkorigins\_source = {true}; raw\_reference = {Trowbridge, A. C., 1930, Building of the Mississippi delta: Bulletin of the American Association of Petroleum Geologists, v. 38, p. 167-192.}"
}

@misc{fisk1944geological1,
    author = "Fisk, H. N",
    title = "Geological Investigation of the Alluvial Valley of the Lower Mississippi Valley",
    year = "1944",
    howpublished = "Vicksburg, Mississippi, Mississippi River Commission, 78 p",
    note = "talkorigins\_source = {true}; raw\_reference = {Fisk, H. N., 1944, Geological Investigation of the Alluvial Valley of the Lower Mississippi Valley: Vicksburg, Mississippi, Mississippi River Commission, 78 p.}"
}

@article{openalexw2624723610,
    author = "Fisk, H. N.",
    title = "Results of geological investigations of the alluvial valley of the lower Mississippi River: Lectures 3-4, Application of geological studies",
    year = "1946",
    journal = "US Army Corps of Engineers: Engineer Research and Development Center (Knowledge Core)",
    url = "https://openalex.org/W2624723610",
    openalex = "W2624723610"
}

@article{doi102307211375,
    author = "Flint, Richard Foster and Fisk, H. N.",
    title = "Geological Investigation of the Alluvial Valley of the Lower Mississippi River",
    year = "1947",
    journal = "Geographical Review",
    url = "https://doi.org/10.2307/211375",
    doi = "10.2307/211375",
    openalex = "W2327685420"
}

@article{flint1947geological,
    author = "Flint, Richard Foster and Fisk, Harold N.",
    title = "Geological Investigation of the Alluvial Valley of the Lower Mississippi River",
    year = "1947",
    journal = "Geographical Review",
    url = "https://doi.org/10.2307/211375",
    doi = "10.2307/211375",
    number = "1",
    openalex = "W2327685420",
    pages = "166",
    volume = "37"
}

@article{hobbs1947geological,
    author = "Hobbs, William Herbert",
    title = "Geological Investigation of the Alluvial Valley of the Lower Mississippi River. Harold N. Fisk",
    year = "1947",
    journal = "The Journal of Geology",
    url = "https://doi.org/10.1086/625442",
    doi = "10.1086/625442",
    number = "4",
    openalex = "W2512314070",
    pages = "378-380",
    volume = "55"
}

@misc{fisk1955late2,
    author = "Fisk, H. N. and McFarlan, E. and Jr",
    title = "Late Quaternary deltaic deposits of the Mississippi River",
    year = "1955",
    howpublished = "Geological Society of America, Special Paper, v. 62, p. 279-302",
    note = "talkorigins\_source = {true}; raw\_reference = {Fisk, H. N., and McFarlan, E., Jr., 1955, Late Quaternary deltaic deposits of the Mississippi River: Geological Society of America, Special Paper, v. 62, p. 279-302.}"
}

A bar on the Brazos River near Calvert, Texas, has been analyzed in order to determine the geologic meaning of certain grain size parameters and to study the behavior of the size fractions with transport. The bar consists of a strongly bimodal mixture of pebble gravel and medium to fine sand; there is a lack of material in the range of 0.5 to 2 mm, because the source does not supply particles of this size. The size distributions of the two modes, which were established in the parent deposits, are nearly invariant over the bar because the present environment of deposition only affects the relative proportions of the two modes, not the grain size properties of the modes themselves. Two proportions are most common; the sediment either contains no gravel or else contains about 60% gravel. Three sediment types with characteristic bedding features occur on the bar in constant stratigraphic order, with the coarsest at the base. Statistical analysis of the data is based on a series of grain size parameters modified from those of Inman (1952) to provide a more detailed coverage of non-normal size curves. Unimodal sediments have nearly normal curves as defined by their skewness and kurtosis. Non-normal kurtosis and skewness values are held to be the identifying characteristics of bimodal sediments even where such modes are not evident in frequency curves. The relative proportions of each mode define a systematic series of changes in numerical properties; mean size, standard deviation and skewness are shown to be linked in a helical trend, which is believed to be applicable to many other sedimentary suites. The equations of the helix may be characteristic of certain environments. Kurtosis values show rhythmic pulsations along the helix and are diagnostic of two-generation sediments.

@article{doi10130674d706462b2111d78648000102c1865d,
    author = "Folk, Robert L. and Ward, W",
    title = "Brazos River bar [Texas]; a study in the significance of grain size parameters",
    year = "1957",
    journal = "Journal of Sedimentary Research",
    abstract = "A bar on the Brazos River near Calvert, Texas, has been analyzed in order to determine the geologic meaning of certain grain size parameters and to study the behavior of the size fractions with transport. The bar consists of a strongly bimodal mixture of pebble gravel and medium to fine sand; there is a lack of material in the range of 0.5 to 2 mm, because the source does not supply particles of this size. The size distributions of the two modes, which were established in the parent deposits, are nearly invariant over the bar because the present environment of deposition only affects the relative proportions of the two modes, not the grain size properties of the modes themselves. Two proportions are most common; the sediment either contains no gravel or else contains about 60\% gravel. Three sediment types with characteristic bedding features occur on the bar in constant stratigraphic order, with the coarsest at the base. Statistical analysis of the data is based on a series of grain size parameters modified from those of Inman (1952) to provide a more detailed coverage of non-normal size curves. Unimodal sediments have nearly normal curves as defined by their skewness and kurtosis. Non-normal kurtosis and skewness values are held to be the identifying characteristics of bimodal sediments even where such modes are not evident in frequency curves. The relative proportions of each mode define a systematic series of changes in numerical properties; mean size, standard deviation and skewness are shown to be linked in a helical trend, which is believed to be applicable to many other sedimentary suites. The equations of the helix may be characteristic of certain environments. Kurtosis values show rhythmic pulsations along the helix and are diagnostic of two-generation sediments.",
    url = "https://doi.org/10.1306/74d70646-2b21-11d7-8648000102c1865d",
    doi = "10.1306/74d70646-2b21-11d7-8648000102c1865d",
    openalex = "W2159525271"
}

ABSTRACT Seaward progradation of the land surface by the present and former Mississippi River deltas has created the Recent deltaic plain of southeastern Louisiana. Each time the Mississippi has advanced a major deltaic lobe seaward, subsequent abandonment of the overly extended river course in favor of a shorter, more direct route to the Gulf has occurred. These course changes and accompanying shifts in centers of deposition have resulted in the distribution of deltaic sediments along a 200-mile arc in coastal Louisiana. As soon as a depositional center or delta is abandoned, marine transgression begins. This process is aided by subsidence of the deltaic plain resulting from tectonism and gradual consolidation of deltaic deposits. Nevertheless, the net result of the struggle between the advancing deltas and the encroaching sea has been an overall increase in the size of the Recent deltaic plain. The sediments of four major depositional environments are complexly interfingered in the deltaic plain: (1) fluvial—natural levee, point bar, abandoned course, and abandoned distributary sediments deposited in fresh to brackish water, principally in inland areas within and along streams; (2) fluvial-marine—prodelta, intradelta, and interdistributary sediments laid down near the mouths of distributary channels in brackish to marine water; (3) paludal—marsh, swamp, tidal channel, and lacustrine deposits formed primarily in situ; and (4) marine—bay-sound, reef, beach, and nearshore Gulf sediments formed by erosion and deposition in marine water. Processes active within each environment and the distribution and physical properties of associated deposits or soil types are of vital interest in investigations of engineering geologists.

@article{doi101306a66337f616c011d78645000102c1865d,
    author = "Kolb, Charles R. and Lopik, Jack R. Van",
    title = "Depositional Environments of Mississippi River Deltaic Plain—Southeastern Louisiana",
    year = "1965",
    journal = "AAPG Bulletin",
    abstract = "ABSTRACT Seaward progradation of the land surface by the present and former Mississippi River deltas has created the Recent deltaic plain of southeastern Louisiana. Each time the Mississippi has advanced a major deltaic lobe seaward, subsequent abandonment of the overly extended river course in favor of a shorter, more direct route to the Gulf has occurred. These course changes and accompanying shifts in centers of deposition have resulted in the distribution of deltaic sediments along a 200-mile arc in coastal Louisiana. As soon as a depositional center or delta is abandoned, marine transgression begins. This process is aided by subsidence of the deltaic plain resulting from tectonism and gradual consolidation of deltaic deposits. Nevertheless, the net result of the struggle between the advancing deltas and the encroaching sea has been an overall increase in the size of the Recent deltaic plain. The sediments of four major depositional environments are complexly interfingered in the deltaic plain: (1) fluvial—natural levee, point bar, abandoned course, and abandoned distributary sediments deposited in fresh to brackish water, principally in inland areas within and along streams; (2) fluvial-marine—prodelta, intradelta, and interdistributary sediments laid down near the mouths of distributary channels in brackish to marine water; (3) paludal—marsh, swamp, tidal channel, and lacustrine deposits formed primarily in situ; and (4) marine—bay-sound, reef, beach, and nearshore Gulf sediments formed by erosion and deposition in marine water. Processes active within each environment and the distribution and physical properties of associated deposits or soil types are of vital interest in investigations of engineering geologists.",
    url = "https://doi.org/10.1306/a66337f6-16c0-11d7-8645000102c1865d",
    doi = "10.1306/a66337f6-16c0-11d7-8645000102c1865d",
    openalex = "W2027858708"
}

ABSTRACT Sixteen separate delta lobes have been formed by the Mississippi River in the past 6,000 years. Fourteen are included in the Teche, St. Bernard, and Lafourche delta complexes; the remaining two include the present birdfoot delta, which is an extension of the earlier formed initial lobe of the Plaquemines-Modern complex. Each delta complex is genetically related to a major Mississippi River course. Individual delta lobes within each complex are the result of the successive distributary networks of a major river course. Delta lobes were defined by detailed facies analyses of sediment cores from hundreds of shallow borings combined with lithologic and faunal data from several hundred additional borings. Each lobe consists of a basal fine-grained prodelta facies, an overlying sandy delta-front facies, and uppermost fine-grained delta-plain facies. The latter deposits include peat accumulations and nonorganic floodplain and natural-levee deposits. More than one hundred radiocarbon age determinations made on discrete delta-plain peats have been used to establish the chronology of the 16 delta lobes. These data, together with the facies relationships, indicate that the development of each delta complex was not a continual process; instead, river shifting from one major course to another caused the temporary cessation of development in one delta complex as progradation occurred in another. Similar deltaic sequences, prevalent in Tertiary outcrops along the northern flank of the Gulf Coast geosyncline, extend basinward as massive subsurface clastic wedges which constitute a major portion of the peripheral basin fill.

@article{openalexw1592594904,
    author = "Frazier, David E.",
    title = "Recent Deltaic Deposits of the Mississippi River: Their Development and Chronology",
    year = "1967",
    abstract = "ABSTRACT Sixteen separate delta lobes have been formed by the Mississippi River in the past 6,000 years. Fourteen are included in the Teche, St. Bernard, and Lafourche delta complexes; the remaining two include the present birdfoot delta, which is an extension of the earlier formed initial lobe of the Plaquemines-Modern complex. Each delta complex is genetically related to a major Mississippi River course. Individual delta lobes within each complex are the result of the successive distributary networks of a major river course. Delta lobes were defined by detailed facies analyses of sediment cores from hundreds of shallow borings combined with lithologic and faunal data from several hundred additional borings. Each lobe consists of a basal fine-grained prodelta facies, an overlying sandy delta-front facies, and uppermost fine-grained delta-plain facies. The latter deposits include peat accumulations and nonorganic floodplain and natural-levee deposits. More than one hundred radiocarbon age determinations made on discrete delta-plain peats have been used to establish the chronology of the 16 delta lobes. These data, together with the facies relationships, indicate that the development of each delta complex was not a continual process; instead, river shifting from one major course to another caused the temporary cessation of development in one delta complex as progradation occurred in another. Similar deltaic sequences, prevalent in Tertiary outcrops along the northern flank of the Gulf Coast geosyncline, extend basinward as massive subsurface clastic wedges which constitute a major portion of the peripheral basin fill.",
    url = "https://openalex.org/W1592594904",
    openalex = "W1592594904"
}

@article{sabate1968pleistocene4,
    author = "Sabate, R. W",
    title = "Pleistocene oil and gas in central Louisiana",
    year = "1968",
    journal = "Gulf Coast Association of Geological Societies Transactions, v. 18, p. 373-386",
    note = "talkorigins\_source = {true}; raw\_reference = {Sabate, R. W., 1968, Pleistocene oil and gas in central Louisiana: Gulf Coast Association of Geological Societies Transactions, v. 18, p. 373-386.}"
}

@article{stuart1976form5,
    author = "Stuart, C. J. and Caughey, C. A",
    title = "Form and composition of the Mississippi fan",
    year = "1976",
    journal = "Gulf Coast Association of Geological Societies Transactions, v. 26, p. 333-343",
    note = "talkorigins\_source = {true}; raw\_reference = {Stuart, C. J., and Caughey, C. A., 1976, Form and composition of the Mississippi fan: Gulf Coast Association of Geological Societies Transactions, v. 26, p. 333-343.}"
}

Abstract This article serves as an introduction to the papers dealing with braided river deposits in this volume. A lithofacies code erected earlier by the writer is expanded to include matrix-supported gravel, low-angle cross stratified sand, erosion surfaces with intraclast conglomerates, and massive mud deposits. The four vertical profile models erected by the writer are expanded to six. A new model, the “Trollheim type” is proposed, to include gravelly deposits characterized by abundant debris flows. The Donjek sequence type is restricted to gravel-dominated cyclic deposits and a new model, the “South Saskatchewan type”, is erected for sand dominated cyclic deposits. The Scott, Platte and Bijou Creek models remain essentially unchanged.

@article{openalexw1912927042,
    author = "Miall, Andrew D.",
    title = "Lithofacies Types and Vertical Profile Models in Braided River Deposits: A Summary",
    year = "1977",
    abstract = "Abstract This article serves as an introduction to the papers dealing with braided river deposits in this volume. A lithofacies code erected earlier by the writer is expanded to include matrix-supported gravel, low-angle cross stratified sand, erosion surfaces with intraclast conglomerates, and massive mud deposits. The four vertical profile models erected by the writer are expanded to six. A new model, the “Trollheim type” is proposed, to include gravelly deposits characterized by abundant debris flows. The Donjek sequence type is restricted to gravel-dominated cyclic deposits and a new model, the “South Saskatchewan type”, is erected for sand dominated cyclic deposits. The Scott, Platte and Bijou Creek models remain essentially unchanged.",
    openalex = "W1912927042",
    references = "doi1010160037073878900015, doi101086627271, doi101111j136530911972tb00013x, doi101111j136530911973tb01615x, doi101111j136530911977tb01915x, doi101111j146783061963tb00464x, doi10113000167606195465175goafis20co2, doi101139e76010, doi10130674d71cf32b2111d78648000102c1865d, doi102475ajs2668609"
}

@misc{moore1979investigation3,
    author = "Moore, G. T. and Woodbury, H. O. and Worzel, J. L. and Watkins, J. S. and Starke, G. W",
    title = "Investigation of the Mississippi Fan, Gulf of Mexico, in Geological and Geophysical Investigations of Continental Margins, 29 of AAPG Memoirs",
    year = "1979",
    howpublished = "p. 383-402",
    note = "talkorigins\_source = {true}; raw\_reference = {Moore, G. T., Woodbury, H. O., Worzel, J. L., Watkins, J. S., and Starke, G. W., 1979, Investigation of the Mississippi Fan, Gulf of Mexico, in Geological and Geophysical Investigations of Continental Margins, 29 of AAPG Memoirs: p. 383-402.}"
}

ABSTRACT Systematic measurements and comparisons of maps, black-and-white aerial photographs, and color infrared imagery taken at five periods within the interval from 1890-1978 have been used to document land loss and habitat change within the Mississippi River Deltaic Plain. The studies show that the long-term trend of net progradation, which persisted through most of the past 5000 years, was reversed during the late nineteenth century, and that during the twentieth century land-loss rates have accelerated geometrically. Within the 11,500 mi2 study area, land-loss rates have progressed from approximately 6.7 mi2/year in 1913 to a projected 39.4 mi2/year in 1980. The greatest loss has occurred in the wetlands, but barrier islands and natural-levee ridges are also disappearing at a very high rate. The data can be used not only to document past change, but also to project future conditions. The findings have great significance to fish and wildlife resources, flood-protection planning, and land ownership. Apparent causes of the high rates of land loss include the harnessing of the Mississippi River by levees and control structures which reduce tendencies toward natural diversion and funnel valuable sediments to deep, offshore waters. Additional factors include canal dredging and accelerated subsidence related to mineral extraction, both of which are often associated with saltwater intrusion. The net effect is a rapidly accelerating man-induced transgression of a major coastal system.

@article{openalexw1852367402,
    author = "Gagliano, Sherwood M. and Meyer‐Arendt, Klaus J. and Wicker, Karen M.",
    title = "Land loss in the Mississippi River Deltaic Plain",
    year = "1981",
    abstract = "ABSTRACT Systematic measurements and comparisons of maps, black-and-white aerial photographs, and color infrared imagery taken at five periods within the interval from 1890-1978 have been used to document land loss and habitat change within the Mississippi River Deltaic Plain. The studies show that the long-term trend of net progradation, which persisted through most of the past 5000 years, was reversed during the late nineteenth century, and that during the twentieth century land-loss rates have accelerated geometrically. Within the 11,500 mi2 study area, land-loss rates have progressed from approximately 6.7 mi2/year in 1913 to a projected 39.4 mi2/year in 1980. The greatest loss has occurred in the wetlands, but barrier islands and natural-levee ridges are also disappearing at a very high rate. The data can be used not only to document past change, but also to project future conditions. The findings have great significance to fish and wildlife resources, flood-protection planning, and land ownership. Apparent causes of the high rates of land loss include the harnessing of the Mississippi River by levees and control structures which reduce tendencies toward natural diversion and funnel valuable sediments to deep, offshore waters. Additional factors include canal dredging and accelerated subsidence related to mineral extraction, both of which are often associated with saltwater intrusion. The net effect is a rapidly accelerating man-induced transgression of a major coastal system.",
    url = "https://openalex.org/W1852367402",
    openalex = "W1852367402"
}

New data and new estimates from old data show that rivers with large sediment loads (annual discharges greater than about tons) contribute about tons of suspended sediment to the ocean yearly. Extrapolating available data for all drainage basins, the total suspended sediment delivered by all rivers to the oceans is about tons annually; bedload and flood discharges may account for an additional tons. About 70% of this total is derived from southern Asia and the larger islands in the Pacific and Indian Oceans, where sediment yields are much greater than for other drainage basins.

@article{doi101086628741,
    author = "Milliman, John D. and Meade, Robert H.",
    title = "World-Wide Delivery of River Sediment to the Oceans",
    year = "1983",
    journal = "The Journal of Geology",
    abstract = "New data and new estimates from old data show that rivers with large sediment loads (annual discharges greater than about tons) contribute about tons of suspended sediment to the ocean yearly. Extrapolating available data for all drainage basins, the total suspended sediment delivered by all rivers to the oceans is about tons annually; bedload and flood discharges may account for an additional tons. About 70\% of this total is derived from southern Asia and the larger islands in the Pacific and Indian Oceans, where sediment yields are much greater than for other drainage basins.",
    url = "https://doi.org/10.1086/628741",
    doi = "10.1086/628741",
    openalex = "W2041158780",
    references = "doi1010160025322781901663, doi101029wr004i004p00737, doi101038278161a0, doi1010970001069419610800000029, doi101130001676061967781203tgotar20co2, doi1011300091761319764105dotist20co2, doi101130gsabp2911, doi101306m20377, doi102110pec7203, doi102110pec7217"
}

Seasonal sedimentation, measured with the aid of artificial marker horizons, was markedly different in deteriorating as compared with stable marshes in the Mississippi River deltaic plain. Deteriorating marshes receive most sediment during storm events, whereas stable marshes receive substantial amounts of sediments during the spring river flood. The deteriorating marshes are accreting at a faster rate (1.5 centimeters per year at streamside, 0.9 centimeter per year at inland areas) than the stable marshes (1.3 centimeters per year at streamside, 0.6 centimeter per year at inland areas). However, relative to local apparent sea-level rise as measured by tide gauges in each area, the deteriorating marshes are not maintaining their intertidal elevation as well as the stable marshes. These results indicate the importance of considering accretion relative to submergence.

@article{doi101126science22446531093,
    author = "Baumann, Robert H. and Day, John W. and Miller, Carolyn A.",
    title = "Mississippi Deltaic Wetland Survival: Sedimentation Versus Coastal Submergence",
    year = "1984",
    journal = "Science",
    abstract = "Seasonal sedimentation, measured with the aid of artificial marker horizons, was markedly different in deteriorating as compared with stable marshes in the Mississippi River deltaic plain. Deteriorating marshes receive most sediment during storm events, whereas stable marshes receive substantial amounts of sediments during the spring river flood. The deteriorating marshes are accreting at a faster rate (1.5 centimeters per year at streamside, 0.9 centimeter per year at inland areas) than the stable marshes (1.3 centimeters per year at streamside, 0.6 centimeter per year at inland areas). However, relative to local apparent sea-level rise as measured by tide gauges in each area, the deteriorating marshes are not maintaining their intertidal elevation as well as the stable marshes. These results indicate the importance of considering accretion relative to submergence.",
    url = "https://doi.org/10.1126/science.224.4653.1093",
    doi = "10.1126/science.224.4653.1093",
    openalex = "W2026702170"
}

Journal Article Changes in Mississippi River Water Quality this Century: Implications for coastal food webs Get access R. Eugene Turner, R. Eugene Turner Search for other works by this author on: Oxford Academic Google Scholar Nancy N. Rabalais Nancy N. Rabalais Search for other works by this author on: Oxford Academic Google Scholar BioScience, Volume 41, Issue 3, March 1991, Pages 140–147, https://doi.org/10.2307/1311453 Published: 01 March 1991

@article{doi1023071311453,
    author = "Turner, R. Eugene and Rabalais, Nancy N.",
    title = "Changes in Mississippi River Water Quality This Century",
    year = "1991",
    journal = "BioScience",
    abstract = "Journal Article Changes in Mississippi River Water Quality this Century: Implications for coastal food webs Get access R. Eugene Turner, R. Eugene Turner Search for other works by this author on: Oxford Academic Google Scholar Nancy N. Rabalais Nancy N. Rabalais Search for other works by this author on: Oxford Academic Google Scholar BioScience, Volume 41, Issue 3, March 1991, Pages 140–147, https://doi.org/10.2307/1311453 Published: 01 March 1991",
    url = "https://doi.org/10.2307/1311453",
    doi = "10.2307/1311453",
    openalex = "W1973728731",
    references = "doi1010079781441985361"
}

Analysis of data from 280 rivers discharging to the ocean indicates that sediment loads/yields are a log-linear function of basin area and maximum elevation of the river basin. Other factors controlling sediment discharge (e.g., climate, runoff) appear to have secondary importance. A notable exception is the influence of human activity, climate, and geology on the rivers draining southern Asia and Oceania. Sediment fluxes from small mountainous rivers, many of which discharge directly onto active margins (e.g., western South and North America and most high-standing oceanic islands), have been greatly underestimated in previous global sediment budgets, perhaps by as much as a factor of three. In contrast, sediment fluxes to the ocean from large rivers (nearly all of which discharge onto passive margins or marginal seas) have been overestimated, as some of the sediment load is subaerially sequestered in subsiding deltas. Before the proliferation of dam construction in the latter half of this century, rivers probably discharged about 20 billion tons of sediment annually to the ocean. Prior to widespread farming and deforestation (beginning 2000-2500 yr ago), however, sediment discharge probably was less than half the present level. Sediments discharged by small mountainous rivers are more likely to escape to the deep sea during high stands of sea level by virtue of a greater impact of episodic events (i.e., flash floods and earthquakes) on small drainage basins and because of the narrow shelves associated with active margins. The resulting delta/fan deposits can be distinctly different than the sedimentary deposits derived from larger rivers that discharge onto passive margins.

@article{doi101086629606,
    author = "Milliman, John D. and Syvitski, James P. M.",
    title = "Geomorphic/Tectonic Control of Sediment Discharge to the Ocean: The Importance of Small Mountainous Rivers",
    year = "1992",
    journal = "The Journal of Geology",
    abstract = "Analysis of data from 280 rivers discharging to the ocean indicates that sediment loads/yields are a log-linear function of basin area and maximum elevation of the river basin. Other factors controlling sediment discharge (e.g., climate, runoff) appear to have secondary importance. A notable exception is the influence of human activity, climate, and geology on the rivers draining southern Asia and Oceania. Sediment fluxes from small mountainous rivers, many of which discharge directly onto active margins (e.g., western South and North America and most high-standing oceanic islands), have been greatly underestimated in previous global sediment budgets, perhaps by as much as a factor of three. In contrast, sediment fluxes to the ocean from large rivers (nearly all of which discharge onto passive margins or marginal seas) have been overestimated, as some of the sediment load is subaerially sequestered in subsiding deltas. Before the proliferation of dam construction in the latter half of this century, rivers probably discharged about 20 billion tons of sediment annually to the ocean. Prior to widespread farming and deforestation (beginning 2000-2500 yr ago), however, sediment discharge probably was less than half the present level. Sediments discharged by small mountainous rivers are more likely to escape to the deep sea during high stands of sea level by virtue of a greater impact of episodic events (i.e., flash floods and earthquakes) on small drainage basins and because of the narrow shelves associated with active margins. The resulting delta/fan deposits can be distinctly different than the sedimentary deposits derived from larger rivers that discharge onto passive margins.",
    url = "https://doi.org/10.1086/629606",
    doi = "10.1086/629606",
    openalex = "W2026886308",
    references = "doi10100797814612378841, doi10102991rg00969, doi101029tr039i006p01076, doi101029wr004i004p00737, doi101086628741, doi101126science2284698488, doi101126science23547931156, doi101130001676061967781203tgotar20co2, doi102307635458, doi102475ajs2683243, openalexw2338892475"
}

Baselevel is the imaginary horizontal level or surface to which sub-aerial erosion proceeds. It is sea level. Controversy surrounds the effect of baselevel change on river behavior, the rejuvenation of landscapes, and the delivery of sediment to the shelf-slope depositional system. The effect of baselevel change depends upon many factors, such as rate of change, amount of change, direction of change, river character, and dynamics and erodibility of the sediment source area. In most cases the effects of baselevel change will be moderate, and they can be accommodated by changes of channel pattern, width, depth, and roughness. Therefore, the delivery of large amounts of sediment to a shoreline or continental shelf probably reflects not only baselevel lowering, but significant uplift of the sediment-source area and perhaps climate change.

@article{doi101086648221,
    author = "Schumm, Stanley A.",
    title = "River Response to Baselevel Change: Implications for Sequence Stratigraphy",
    year = "1993",
    journal = "The Journal of Geology",
    abstract = "Baselevel is the imaginary horizontal level or surface to which sub-aerial erosion proceeds. It is sea level. Controversy surrounds the effect of baselevel change on river behavior, the rejuvenation of landscapes, and the delivery of sediment to the shelf-slope depositional system. The effect of baselevel change depends upon many factors, such as rate of change, amount of change, direction of change, river character, and dynamics and erodibility of the sediment source area. In most cases the effects of baselevel change will be moderate, and they can be accommodated by changes of channel pattern, width, depth, and roughness. Therefore, the delivery of large amounts of sediment to a shoreline or continental shelf probably reflects not only baselevel lowering, but significant uplift of the sediment-source area and perhaps climate change.",
    url = "https://doi.org/10.1086/648221",
    doi = "10.1086/648221",
    openalex = "W2074438535",
    references = "doi10100797814612378841, doi1011300016760619881001661fyoss23co2, doi101306703c9af5170711d78645000102c1865d, doi102110pec88010109"
}

Anabranching rivers consist of multiple channels separated by vegetated semi-permanent alluvial islands excised from existing floodplain or formed by within-channel or deltaic accretion. These rivers occupy a wide range of environments from low to high energy, however, their existence has never been adequately explained. They occur concurrently with other types of channel pattern, although specific requirements include a flood-dominated flow regime and banks that are resistant to erosion, with some systems characterized by mechanisms to block or constrict channels, thereby triggering avulsion. The fundamental advantage of an anabranching river is that, by constructing a semi-permanent system of multiple channels, it can concentrate stream flow and maximize bed-sediment transport (work per unit area of the bed) under conditions where there is little or no opportunity to increase gradient. On the basis of stream energy, sediment size and morphological characteristics, six types of anabranching river are recognized; types 1–3 are lower energy and types 4–6 are higher energy systems. Type 1 are cohesive sediment rivers (commonly termed anastomosing) with low w/d ratio channels that exhibit little or no lateral migration. They are divisible into three subtypes based on vegetative and sedimentary environment. Type 2 are sand-dominated, island-forming rivers, and type 3 are mixed-load laterally active meandering rivers. Type 4 are sand-dominated, ridge-forming rivers characterized by long, parallel, channel-dividing ridges. Type 5 are gravel-dominated, laterally active systems that interface between meandering and braiding in mountainous regions. Type 6 are gravel-dominated, stable systems that occur as non-migrating channels in small, relatively steep basins. Anabranching rivers represent a relatively uncommon but widespread and distinctive group that, because of particular sedimentary, energy-gradient and other hydraulic conditions, operate most effectively as a system of multiple channels separated by vegetated floodplain islands or alluvial ridges.

@article{doi101002sici10969837199603213217aidesp61130co2u,
    author = "Nanson, Gerald C. and Knighton, A. D.",
    title = "ANABRANCHING RIVERS: THEIR CAUSE, CHARACTER AND CLASSIFICATION",
    year = "1996",
    journal = "Earth Surface Processes and Landforms",
    abstract = "Anabranching rivers consist of multiple channels separated by vegetated semi-permanent alluvial islands excised from existing floodplain or formed by within-channel or deltaic accretion. These rivers occupy a wide range of environments from low to high energy, however, their existence has never been adequately explained. They occur concurrently with other types of channel pattern, although specific requirements include a flood-dominated flow regime and banks that are resistant to erosion, with some systems characterized by mechanisms to block or constrict channels, thereby triggering avulsion. The fundamental advantage of an anabranching river is that, by constructing a semi-permanent system of multiple channels, it can concentrate stream flow and maximize bed-sediment transport (work per unit area of the bed) under conditions where there is little or no opportunity to increase gradient. On the basis of stream energy, sediment size and morphological characteristics, six types of anabranching river are recognized; types 1–3 are lower energy and types 4–6 are higher energy systems. Type 1 are cohesive sediment rivers (commonly termed anastomosing) with low w/d ratio channels that exhibit little or no lateral migration. They are divisible into three subtypes based on vegetative and sedimentary environment. Type 2 are sand-dominated, island-forming rivers, and type 3 are mixed-load laterally active meandering rivers. Type 4 are sand-dominated, ridge-forming rivers characterized by long, parallel, channel-dividing ridges. Type 5 are gravel-dominated, laterally active systems that interface between meandering and braiding in mountainous regions. Type 6 are gravel-dominated, stable systems that occur as non-migrating channels in small, relatively steep basins. Anabranching rivers represent a relatively uncommon but widespread and distinctive group that, because of particular sedimentary, energy-gradient and other hydraulic conditions, operate most effectively as a system of multiple channels separated by vegetated floodplain islands or alluvial ridges.",
    url = "https://doi.org/10.1002/(sici)1096-9837(199603)21:3<217::aid-esp611>3.0.co;2-u",
    doi = "10.1002/(sici)1096-9837(199603)21:3<217::aid-esp611>3.0.co;2-u",
    openalex = "W2097996280",
    references = "doi1010160037073869900104, doi1010160169555x9290039q, doi101111j136530911989tb00817x"
}

@article{doi1023071352458,
    author = "Rabalais, Nancy N. and Turner, R. Eugene and Justić, Dubravko and Dortch, Quay and Wiseman, William J. and Gupta, Barun K. Sen and Justić, Dubravko",
    title = "Nutrient Changes in the Mississippi River and System Responses on the Adjacent Continental Shelf",
    year = "1996",
    journal = "Estuaries",
    url = "https://doi.org/10.2307/1352458",
    doi = "10.2307/1352458",
    openalex = "W1979102125",
    references = "doi101038368619a0, doi101086628741, doi101111j174973451990tb00529x, doi101126science223463122, doi102216i00318884322791, doi1023071311453, doi1023072992511, doi102475ajs2824401, doi104319lo1988334part20796, openalexw3146967818"
}

Seasonally severe hypoxia (≤2 mg O2 l−1) occurs in waters below the pycnocline on the northern Gulf of Mexico inner continental shelf in May through September over extensive areas (up to 18 000 km2). Spatial and temporal variability in the distribution of hypoxic water masses is related, in part, to the amplitude and phasing of freshwater discharge from the Mississippi and Atchafalaya Rivers, circulation patterns, nutrient flux and a close coupling with net productivity. The Mississippi River flood in 1993 and sustained freshwater inputs to the Gulf of Mexico occurred during mid-summer through early autumn when long-term mean flows (1930–1995) are normally lowest. Long-term studies of the Louisiana shelf hypoxic zone provided a natural experiment to examine the effects of extreme high river flow on the adjacent continental shelf. Oxygen levels in bottom waters were severely reduced in July, August and September compared to long-term averages (1985–1992). Also, the areal extent of the bottom-water hypoxia in mid-summer 1993 was approximately twice as large as the average area mapped in the previous 8 years during mid-summer shelfwide surveys. Contributing to increased severity and areal extent of hypoxia in 1993 were reduced surface water salinities, increased strength of the pycnocline, five to ten times higher nutrient concentrations, greater phytoplankton biomass, an order of magnitude greater abundance of phytoplankton, mostly small, coccoid cyanobacteria, and a shift in diatom community dynamics. An equally extensive hypoxic zone in mid-summer of 1994, when riverine fluxes of freshwater and nutrients were ‘normal’, suggests some residual effects of the 1993 summer flooding. © 1998 John Wiley & Sons, Ltd.

@article{doi101002sici1099164619980304142161aidrrr49530co2j,
    author = "Rabalais, Nancy N. and Turner, R. Eugene and Wiseman, William J. and Dortch, Quay",
    title = "Consequences of the 1993 Mississippi River flood in the Gulf of Mexico",
    year = "1998",
    journal = "Regulated Rivers Research \& Management",
    abstract = "Seasonally severe hypoxia (≤2 mg O2 l−1) occurs in waters below the pycnocline on the northern Gulf of Mexico inner continental shelf in May through September over extensive areas (up to 18 000 km2). Spatial and temporal variability in the distribution of hypoxic water masses is related, in part, to the amplitude and phasing of freshwater discharge from the Mississippi and Atchafalaya Rivers, circulation patterns, nutrient flux and a close coupling with net productivity. The Mississippi River flood in 1993 and sustained freshwater inputs to the Gulf of Mexico occurred during mid-summer through early autumn when long-term mean flows (1930–1995) are normally lowest. Long-term studies of the Louisiana shelf hypoxic zone provided a natural experiment to examine the effects of extreme high river flow on the adjacent continental shelf. Oxygen levels in bottom waters were severely reduced in July, August and September compared to long-term averages (1985–1992). Also, the areal extent of the bottom-water hypoxia in mid-summer 1993 was approximately twice as large as the average area mapped in the previous 8 years during mid-summer shelfwide surveys. Contributing to increased severity and areal extent of hypoxia in 1993 were reduced surface water salinities, increased strength of the pycnocline, five to ten times higher nutrient concentrations, greater phytoplankton biomass, an order of magnitude greater abundance of phytoplankton, mostly small, coccoid cyanobacteria, and a shift in diatom community dynamics. An equally extensive hypoxic zone in mid-summer of 1994, when riverine fluxes of freshwater and nutrients were ‘normal’, suggests some residual effects of the 1993 summer flooding. © 1998 John Wiley \& Sons, Ltd.",
    url = "https://doi.org/10.1002/(sici)1099-1646(199803/04)14:2<161::aid-rrr495>3.0.co;2-j",
    doi = "10.1002/(sici)1099-1646(199803/04)14:2<161::aid-rrr495>3.0.co;2-j",
    openalex = "W2062806192"
}

An American epic of science, politics, race, honor, high society, and the Mississippi River, Rising Tide tells the riveting and nearly forgotten story of the greatest natural disaster this country has ever known-- the Mississippi flood of 1927. The river inundated the homes of nearly one million people, helped elect Huey Long governor and made Herbert Hoover president, drove hundreds of thousands of blacks north, and transformed American society and politics forever. A New York Times Notable Book of the Year, winner of the Southern Book Critics Circle Award and the Lillian Smith Award.

@article{doi10230740027956,
    author = "Watkins, Tri and Barry, John",
    title = "Rising Tide: The Great Mississippi Flood of 1927 and How It Changed America",
    year = "1998",
    journal = "The Arkansas Historical Quarterly",
    abstract = "An American epic of science, politics, race, honor, high society, and the Mississippi River, Rising Tide tells the riveting and nearly forgotten story of the greatest natural disaster this country has ever known-- the Mississippi flood of 1927. The river inundated the homes of nearly one million people, helped elect Huey Long governor and made Herbert Hoover president, drove hundreds of thousands of blacks north, and transformed American society and politics forever. A New York Times Notable Book of the Year, winner of the Southern Book Critics Circle Award and the Lillian Smith Award.",
    url = "https://doi.org/10.2307/40027956",
    doi = "10.2307/40027956",
    openalex = "W2076036065"
}

Over the last century, the river-dominated Mississippi delta has received increasing attention from geoscientists, biologists, engineers, and environmental planners because of the importance of the river and its deltaic environments to the economic well-being of the state of Louisiana and the nation. Population growth, subsurface resource extraction, and increased land-water use have placed demands on the delta's natural geologic, biologic, and chemical systems, therefore modifying the time and spatial scales of natural processes within the delta and its lower alluvial valley. As a result, the combined effects of natural and human-induced processes, such as subsidence, eustatic sea level rise, salt water intrusion, and wetland loss, have produced a dynamically changing landscape and socioeconomic framework for this complex delta. Under natural conditions, the fundamental changes that result in land-building and land loss in the Holocene Mississippi River delta plain are rooted in the systematic diversion of water and sediment associated with major shifts in the river's course-the process of delta switching. Research over the last half century has shown that major relocations of the Mississippi's course have resulted in five Holocene delta complexes and a sixth one in an early stage of development as a product of the latest Atchafalaya River diversion. Collectively, these Holocene deltas have produced a delta plain that covers an area of ~30,000 km and accounts for 41% of the coastal wetlands in the United States. After a river diversion takes place, the resulting delta evolves through a systematic and semipredictable set of stages generally characterized by: (a) rapid progradation with increasing-to-stable discharge, (b) relative stability during initial stages of waning discharge, (c) abandonment by the river in favor of a higher gradient course to the receiving basin, and (d) marine reworking of a sediment-starved delta as it undergoes progressive submergence by the combined processes of subsidence. Delta switching has taken place every 1000 to 2000 years during Holocene times, and resulting deltas have an average thickness of approximately 35 m. Within a single delta there are subdeltas, bayfills, and crevasse-splays that have higher frequency delta cycles ranging from several hundred years to a few decades. These depositional features are usually less than 10 m thick, and some have produced marshland areas of over 300 km. The net result of these delta-building events is a low-lying landscape with components that are changing (building and deteriorating) at different rates. Geologically, these depositional cycles produce a thick accumulation of coarsening, upward deltaic deposits that have various thicknesses in response to development on a variety of temporal and spatial scales. In this river-dominated delta system, distributaries can prograde seaward at rates of over 100 m/year. The cumulative effect of the Holocene depository has been to depress the underlying Pleistocene surface. In a local setting, e.g., the modern Balize Lobe, differential loading causes the vertical displacement of underlying clay-rich facies (shale diapirs-mudlumps). The delta front of this lobe, which has prograded into deep water of the outer continental shelf, is characterized by rapid deposition of silt- and clay-rich sediments and slope instability, which results in seaward displacement of sediments by a variety of mass-movement processes. Superimposed on the natural processes and forms of the Mississippi deltaic plain and its associated estuarine environments, are human impacts, most of which have been imposed in this century. The most significant impacts have resulted from a decrease in sediment input to the river from its tributaries and the alteration of the river's natural sediment dispersal processes through the construction of levees. Measures are now being taken to reinstate some of the delta's natural processes, thereby mitigating landloss so that decline in animal and plant productivity can be mitigated. 2 2

@article{openalexw1846023905,
    author = "Coleman, James M. and Roberts, Harry H. and Stone, Gregory W.",
    title = "Mississippi River Delta: an Overview",
    year = "1998",
    journal = "Civil War Book Review",
    abstract = "Over the last century, the river-dominated Mississippi delta has received increasing attention from geoscientists, biologists, engineers, and environmental planners because of the importance of the river and its deltaic environments to the economic well-being of the state of Louisiana and the nation. Population growth, subsurface resource extraction, and increased land-water use have placed demands on the delta's natural geologic, biologic, and chemical systems, therefore modifying the time and spatial scales of natural processes within the delta and its lower alluvial valley. As a result, the combined effects of natural and human-induced processes, such as subsidence, eustatic sea level rise, salt water intrusion, and wetland loss, have produced a dynamically changing landscape and socioeconomic framework for this complex delta. Under natural conditions, the fundamental changes that result in land-building and land loss in the Holocene Mississippi River delta plain are rooted in the systematic diversion of water and sediment associated with major shifts in the river's course-the process of delta switching. Research over the last half century has shown that major relocations of the Mississippi's course have resulted in five Holocene delta complexes and a sixth one in an early stage of development as a product of the latest Atchafalaya River diversion. Collectively, these Holocene deltas have produced a delta plain that covers an area of \textasciitilde 30,000 km and accounts for 41\% of the coastal wetlands in the United States. After a river diversion takes place, the resulting delta evolves through a systematic and semipredictable set of stages generally characterized by: (a) rapid progradation with increasing-to-stable discharge, (b) relative stability during initial stages of waning discharge, (c) abandonment by the river in favor of a higher gradient course to the receiving basin, and (d) marine reworking of a sediment-starved delta as it undergoes progressive submergence by the combined processes of subsidence. Delta switching has taken place every 1000 to 2000 years during Holocene times, and resulting deltas have an average thickness of approximately 35 m. Within a single delta there are subdeltas, bayfills, and crevasse-splays that have higher frequency delta cycles ranging from several hundred years to a few decades. These depositional features are usually less than 10 m thick, and some have produced marshland areas of over 300 km. The net result of these delta-building events is a low-lying landscape with components that are changing (building and deteriorating) at different rates. Geologically, these depositional cycles produce a thick accumulation of coarsening, upward deltaic deposits that have various thicknesses in response to development on a variety of temporal and spatial scales. In this river-dominated delta system, distributaries can prograde seaward at rates of over 100 m/year. The cumulative effect of the Holocene depository has been to depress the underlying Pleistocene surface. In a local setting, e.g., the modern Balize Lobe, differential loading causes the vertical displacement of underlying clay-rich facies (shale diapirs-mudlumps). The delta front of this lobe, which has prograded into deep water of the outer continental shelf, is characterized by rapid deposition of silt- and clay-rich sediments and slope instability, which results in seaward displacement of sediments by a variety of mass-movement processes. Superimposed on the natural processes and forms of the Mississippi deltaic plain and its associated estuarine environments, are human impacts, most of which have been imposed in this century. The most significant impacts have resulted from a decrease in sediment input to the river from its tributaries and the alteration of the river's natural sediment dispersal processes through the construction of levees. Measures are now being taken to reinstate some of the delta's natural processes, thereby mitigating landloss so that decline in animal and plant productivity can be mitigated. 2 2",
    url = "https://openalex.org/W1846023905",
    openalex = "W1846023905",
    references = "doi101016s0967065397885973, doi101086625561, doi101126science27352821693, doi1011300016760619881000999dcapit23co2, doi101306212f8ec22b2411d78648000102c1865d, doi101306ad461b9216f711d78645000102c1865d, doi101306sv21353, doi102307211375, doi105724gcs91120034, openalexw1592594904, openalexw2971039300"
}

@article{openalexw1585720367,
    author = "Goolsby, Donald A. and Battaglin, William A. and Lawrence, Gregory B. and Artz, Richard S. and Aulenbach, Brent T. and Hooper, Richard and Keeney, D. R. and Stensland, Gary J.",
    title = "Flux and Sources of Nutrients in the Mississippi-Atchafalaya River Basin",
    year = "1999",
    openalex = "W1585720367"
}

@article{doi101016s004896979900532x,
    author = "Goolsby, Donald A. and Battaglin, William A. and Aulenbach, Brent T. and Hooper, Richard",
    title = "Nitrogen flux and sources in the Mississippi River Basin",
    year = "2000",
    journal = "The Science of The Total Environment",
    url = "https://doi.org/10.1016/s0048-9697(99)00532-x",
    doi = "10.1016/s0048-9697(99)00532-x",
    openalex = "W1992557497",
    references = "doi10100797894009177673, doi101007bf02179825, doi101016s0167880997001394, doi10102992wr01008, doi102134jeq199700472425002600040015x, doi102134jeq199700472425002600050007x, doi1023071311453, doi1023071352458, doi103133pp135, openalexw1585720367, openalexw3199303739"
}

Abstract Current and historical data show that nitrogen concentrations and flux in the Mississippi River Basin have increased significantly during the past 100 years. Most of the increase observed in the lower Mississippi River has occurred since the early 1970s and is due almost entirely to an increase in nitrate. The current (1980–99) average annual nitrogen (N) flux from the Mississippi Basin to the Gulf of Mexico is about 1 555 500 t year −1, of which about 62% is nitrate‐N. The remaining 38% is organic nitrogen and a small amount of ammonium. The current (1980–99) average nitrate flux to the Gulf is almost three times larger than it was during 1955–70. This increased supply of nitrogen to the Gulf is believed to be partly responsible for the increasing size of a large hypoxic zone that develops along the Louisiana–Texas shelf each summer. This zone of oxygen‐depleted water has doubled in areal extent since it was first measured in 1985. The increase in annual nitrate flux to the Gulf can be largely explained by three factors: increased fertilizer use, annual variability in precipitation and increased streamflow, and the year‐to‐year variability in the amount of nitrogen available in the soil‐ground water system for leaching to streams. The predominant source areas for the nitrogen transported to the Gulf of Mexico are basins draining southern Minnesota, Iowa, Illinois, Indiana, and Ohio. Basins in this region yield 1801 to 3050 kg N km −2 year −1 to streams, several times the N yield of basins outside this region. Published in 2001 by John Wiley & Sons, Ltd.

@article{doi101002hyp210,
    author = "Goolsby, Donald A. and Battaglin, William A.",
    title = "Long‐term changes in concentrations and flux of nitrogen in the Mississippi River Basin, USA",
    year = "2001",
    journal = "Hydrological Processes",
    abstract = "Abstract Current and historical data show that nitrogen concentrations and flux in the Mississippi River Basin have increased significantly during the past 100 years. Most of the increase observed in the lower Mississippi River has occurred since the early 1970s and is due almost entirely to an increase in nitrate. The current (1980–99) average annual nitrogen (N) flux from the Mississippi Basin to the Gulf of Mexico is about 1 555 500 t year −1, of which about 62\% is nitrate‐N. The remaining 38\% is organic nitrogen and a small amount of ammonium. The current (1980–99) average nitrate flux to the Gulf is almost three times larger than it was during 1955–70. This increased supply of nitrogen to the Gulf is believed to be partly responsible for the increasing size of a large hypoxic zone that develops along the Louisiana–Texas shelf each summer. This zone of oxygen‐depleted water has doubled in areal extent since it was first measured in 1985. The increase in annual nitrate flux to the Gulf can be largely explained by three factors: increased fertilizer use, annual variability in precipitation and increased streamflow, and the year‐to‐year variability in the amount of nitrogen available in the soil‐ground water system for leaching to streams. The predominant source areas for the nitrogen transported to the Gulf of Mexico are basins draining southern Minnesota, Iowa, Illinois, Indiana, and Ohio. Basins in this region yield 1801 to 3050 kg N km −2 year −1 to streams, several times the N yield of basins outside this region. Published in 2001 by John Wiley \& Sons, Ltd.",
    url = "https://doi.org/10.1002/hyp.210",
    doi = "10.1002/hyp.210",
    openalex = "W2089289205",
    references = "doi10100797894009177673, doi101007bf02179825, doi10102992wr01008, doi10103835001562, doi102134jeq199700472425002600040015x, doi102134jeq199700472425002600050007x, doi1023071352458, doi102475ajs2824401, doi103133pp135, openalexw2033633111, openalexw3199303739"
}

@article{doi10103835102672,
    author = "McIsaac, Gregory F. and David, Mark B. and Gertner, George Z. and Goolsby, Donald A.",
    title = "Nitrate flux in the Mississippi River",
    year = "2001",
    journal = "Nature",
    url = "https://doi.org/10.1038/35102672",
    doi = "10.1038/35102672",
    openalex = "W2041340082",
    references = "doi101002hyp210"
}

@article{doi1016410006356820010510373rnlttg20co2,
    author = "Mitsch, William J. and Day, John W. and Gilliam, J. W. and Groffman, Peter M. and Hey, Donald L. and Randall, G. W. and Wang, Naiming",
    title = "Reducing Nitrogen Loading to the Gulf of Mexico from the Mississippi River Basin: Strategies to Counter a Persistent Ecological Problem",
    year = "2001",
    journal = "BioScience",
    url = "https://doi.org/10.1641/0006-3568(2001)051[0373:rnlttg]2.0.co;2",
    doi = "10.1641/0006-3568(2001)051[0373:rnlttg]2.0.co;2",
    openalex = "W2276914180",
    references = "openalexw1852367402"
}

@article{doi101007bf02691346,
    author = "Rybczyk, John and Cahoon, Donald R.",
    title = "Estimating the potential for submergence for two wetlands in the Mississippi River Delta",
    year = "2002",
    journal = "Estuaries",
    url = "https://doi.org/10.1007/bf02691346",
    doi = "10.1007/bf02691346",
    openalex = "W1974226748",
    references = "doi101002esp3290180105, doi101002esp3290200103, doi101006ecss19990522, doi101016002532279500087f, doi101038357293a0, doi10211215515036si54fmi, doi1023071352382, doi104319lo19842951052, openalexw1927292367, openalexw2177590044"
}

Chemical weathering and the subsequent export of carbonate alkalinity (HCO3- + CO3-2) from soils to rivers account for significant amounts of terrestrially sequestered atmospheric CO2. We show here that during the past half-century, the export of this alkalinity has increased dramatically from North America's largest river, the Mississippi. This increased export is in part the result of increased flow resulting from higher rainfall in the Mississippi basin. Subcatchment data from the Mississippi suggest that the increase in the export of alkalinity is also linked to amount and type of land cover. These observations have important implications for the potential management of carbon sequestration in the United States.

@article{doi101126science1083788,
    author = "Raymond, Peter A. and Cole, Jonathan J.",
    title = "Increase in the Export of Alkalinity from North America's Largest River",
    year = "2003",
    journal = "Science",
    abstract = "Chemical weathering and the subsequent export of carbonate alkalinity (HCO3- + CO3-2) from soils to rivers account for significant amounts of terrestrially sequestered atmospheric CO2. We show here that during the past half-century, the export of this alkalinity has increased dramatically from North America's largest river, the Mississippi. This increased export is in part the result of increased flow resulting from higher rainfall in the Mississippi basin. Subcatchment data from the Mississippi suggest that the increase in the export of alkalinity is also linked to amount and type of land cover. These observations have important implications for the potential management of carbon sequestration in the United States.",
    url = "https://doi.org/10.1126/science.1083788",
    doi = "10.1126/science.1083788",
    openalex = "W2094931011",
    references = "doi101002hyp210"
}

Abstract Field surveys and sediment cores were used to estimate marsh erosion and land subsidence at Madison Bay, a well-known wetland loss hot spot in coastal Louisiana. Former marshes of Madison Bay are under about 1 m of water. Nearly two-thirds of the permanent flooding was caused by rapid subsidence in the late 1960s, whereas the other third was caused by subsequent erosion. Subsidence rates near Madison Bay since the 1960s (∼20 mm/yr) are an order of magnitude greater than deltaic subsidence rates averaged for the past 400–4000 yr (∼2 mm/yr). The rapid acceleration and unexpected decline in wetland losses in the Mississippi delta plain are difficult to explain on the basis of most physical and biogeochemical processes. There are, however, close temporal and spatial correlations among regional wetland loss, high subsidence rates, and large-volume fluid production from nearby hydrocarbon fields. The decreased rates of wetland loss since the 1970s may be related to decreased rates of subsidence caused by significantly decreased rates of subsurface fluid withdrawal. Annual fluid production from the Lapeyrouse, Lirette, and Bay Baptiste fields that encompass Madison Bay accelerated in the 1960s, peaked about 1970, and then declined abruptly. Large decreases in pore pressure in the Lapeyrouse field have likely altered subsurface stresses and reactivated a major fault that coincides with the wetland loss hot spot. Therefore, wetland losses at Madison Bay can be closely linked to rapid subsidence and possible fault reactivation induced by long-term, large-volume hydrocarbon production.

@article{doi101306eg04040302007,
    author = "Morton, Robert A. and Tiling, Ginger and Ferina, Nicholas F.",
    title = "Causes of hot-spot wetland loss in the Mississippi delta plain",
    year = "2003",
    journal = "Environmental Geosciences",
    abstract = "Abstract Field surveys and sediment cores were used to estimate marsh erosion and land subsidence at Madison Bay, a well-known wetland loss hot spot in coastal Louisiana. Former marshes of Madison Bay are under about 1 m of water. Nearly two-thirds of the permanent flooding was caused by rapid subsidence in the late 1960s, whereas the other third was caused by subsequent erosion. Subsidence rates near Madison Bay since the 1960s (∼20 mm/yr) are an order of magnitude greater than deltaic subsidence rates averaged for the past 400–4000 yr (∼2 mm/yr). The rapid acceleration and unexpected decline in wetland losses in the Mississippi delta plain are difficult to explain on the basis of most physical and biogeochemical processes. There are, however, close temporal and spatial correlations among regional wetland loss, high subsidence rates, and large-volume fluid production from nearby hydrocarbon fields. The decreased rates of wetland loss since the 1970s may be related to decreased rates of subsidence caused by significantly decreased rates of subsurface fluid withdrawal. Annual fluid production from the Lapeyrouse, Lirette, and Bay Baptiste fields that encompass Madison Bay accelerated in the 1960s, peaked about 1970, and then declined abruptly. Large decreases in pore pressure in the Lapeyrouse field have likely altered subsurface stresses and reactivated a major fault that coincides with the wetland loss hot spot. Therefore, wetland losses at Madison Bay can be closely linked to rapid subsidence and possible fault reactivation induced by long-term, large-volume hydrocarbon production.",
    url = "https://doi.org/10.1306/eg.04040302007",
    doi = "10.1306/eg.04040302007",
    openalex = "W2119246484",
    references = "doi101007bf01867025, doi101007bf01867123, doi101016096706539594262o, doi1023071353136, doi1023072260609, doi103354meps096269, doi105724gcs91120034, openalexw1586892756, openalexw1592594904, openalexw1852367402"
}

Abstract Two centuries of land use in the Mississippi River watershed are reflected in the water quality of its streams and in the continental shelf ecosystem receiving its discharge. The most recent influence on nutrient loading—intense and widespread farming and especially fertilizer use—has had a more significant effect on water quality than has land drainage or the conversion of native vegetation to cropland and grazing pastures. The 200-year record of nutrient loading to offshore water is reflected in the paleoreconstructed record of plankton in dated sediments. This record illustrates that the development of fair, sustained management of inland ecosystems is linked to the management of offshore systems. Land use in this fully occupied watershed is under the strong influence of national policies affecting all aspects of the human ecosphere. These policies can be modified for better or worse, but water quality will probably change only gradually because of the strong buffering capacity of the soil ecosystem.

@article{doi1016410006356820030530563llawqi20co2,
    author = "Turner, R. Eugene and Rabalais, Nancy N.",
    title = "Linking Landscape and Water Quality in the Mississippi River Basin for 200 Years",
    year = "2003",
    journal = "BioScience",
    abstract = "Abstract Two centuries of land use in the Mississippi River watershed are reflected in the water quality of its streams and in the continental shelf ecosystem receiving its discharge. The most recent influence on nutrient loading—intense and widespread farming and especially fertilizer use—has had a more significant effect on water quality than has land drainage or the conversion of native vegetation to cropland and grazing pastures. The 200-year record of nutrient loading to offshore water is reflected in the paleoreconstructed record of plankton in dated sediments. This record illustrates that the development of fair, sustained management of inland ecosystems is linked to the management of offshore systems. Land use in this fully occupied watershed is under the strong influence of national policies affecting all aspects of the human ecosphere. These policies can be modified for better or worse, but water quality will probably change only gradually because of the strong buffering capacity of the soil ecosystem.",
    url = "https://doi.org/10.1641/0006-3568(2003)053[0563:llawqi]2.0.co;2",
    doi = "10.1641/0006-3568(2003)053[0563:llawqi]2.0.co;2",
    openalex = "W2129825297",
    references = "doi10100797836421144347, doi10100797894009177673, doi101007bf02179825, doi101016s0967065397848259, doi101038368619a0, doi10108000785236199510422044, doi1016410006356820010510373rnlttg20co2, doi1018901051076119970070737haotgn20co2, doi1023071313296, doi1023071856261"
}

The effects of nutrient loading from the Mississippi River basin on the areal extent of hypoxia in the northern Gulf of Mexico were examined using a novel application of a dissolved oxygen model for a river. The model,driven by river nitrogen load and a simple parameterization of ocean dynamics, reproduced 17 yr of observed hypoxia location and extent, subpycnocline oxygen consumption, and cross‐pycnocline oxygen flux. With Monte Carlo analysis, we illustrate through hindcasts back to 1968 that extensive regions of low oxygen were not common before the mid‐1970s. The Mississippi River Watershed/Gulf of Mexico Hypoxia Task Force set a goal to reduce the 5‐yr running average size of the Gulf’s hypoxic zone to less than 5,000 km 2 by 2015 and suggested that a 30% reduction from the 1980–1996 average nitrogen load is needed to reach that goal. Here we show that 30% might not be sufficient to reach that goal when year‐to‐year variability in ocean dynamics is considered.

@article{doi104319lo20034830951,
    author = "Scavia, Donald and Rabalais, Nancy N. and Turner, R. Eugene and Justić, Dubravko and Wiseman, William J.",
    title = "Predicting the response of Gulf of Mexico hypoxia to variations in Mississippi River nitrogen load",
    year = "2003",
    journal = "Limnology and Oceanography",
    abstract = "The effects of nutrient loading from the Mississippi River basin on the areal extent of hypoxia in the northern Gulf of Mexico were examined using a novel application of a dissolved oxygen model for a river. The model,driven by river nitrogen load and a simple parameterization of ocean dynamics, reproduced 17 yr of observed hypoxia location and extent, subpycnocline oxygen consumption, and cross‐pycnocline oxygen flux. With Monte Carlo analysis, we illustrate through hindcasts back to 1968 that extensive regions of low oxygen were not common before the mid‐1970s. The Mississippi River Watershed/Gulf of Mexico Hypoxia Task Force set a goal to reduce the 5‐yr running average size of the Gulf’s hypoxic zone to less than 5,000 km 2 by 2015 and suggested that a 30\% reduction from the 1980–1996 average nitrogen load is needed to reach that goal. Here we show that 30\% might not be sufficient to reach that goal when year‐to‐year variability in ocean dynamics is considered.",
    url = "https://doi.org/10.4319/lo.2003.48.3.0951",
    doi = "10.4319/lo.2003.48.3.0951",
    openalex = "W2011307488",
    references = "doi102134jeq2001302329x"
}

@article{openalexw2924487243,
    author = "Woerner, Eric G. and Dunbar, Joseph B. and Villanueva, Evelyn and Smith, Lawson M.",
    title = "Geologic Investigation of the Middle Mississippi River",
    year = "2003",
    journal = "US Army Corps of Engineers: Engineer Research and Development Center (Knowledge Core)",
    url = "https://openalex.org/W2924487243",
    openalex = "W2924487243"
}

The ever increasing need for accurate predictions of global environmental change under greenhouse conditions has sparked immense interest in an abrupt, century‐scale cooling around 8200 years ago, with a focal point in the North Atlantic and with hemispheric teleconnections. Despite considerable progress in the unraveling of this striking feature, including a conceivable driving mechanism (rapid drainage of proglacial Lake Agassiz/Ojibway and a resulting reduced strength of North Atlantic thermohaline circulation), several key questions remain unanswered. One salient aspect concerns the total amount of freshwater released during this catastrophic event, likely echoed by a near‐instantaneous eustatic sea‐level rise. So far, no attempts have been made to perform high‐resolution sea‐level studies that explicitly focus on this critical time interval. Here, we present new data from the Mississippi Delta suggestive of abrupt sea‐level rise associated with the 8.2 ka event. However, the amount of sea‐level rise was likely less than ∼1.2 m, corresponding to a meltwater volume of less than ∼4.3 10 14 m 3; values lower than estimates used by several recent studies.

@article{doi1010292004gl021429,
    author = "Törnqvist, Torbjörn E. and Bick, Scott J. and González, Juan L. and van der Borg, Klaas and de Jong, Arie F. M.",
    title = "Tracking the sea‐level signature of the 8.2 ka cooling event: New constraints from the Mississippi Delta",
    year = "2004",
    journal = "Geophysical Research Letters",
    abstract = "The ever increasing need for accurate predictions of global environmental change under greenhouse conditions has sparked immense interest in an abrupt, century‐scale cooling around 8200 years ago, with a focal point in the North Atlantic and with hemispheric teleconnections. Despite considerable progress in the unraveling of this striking feature, including a conceivable driving mechanism (rapid drainage of proglacial Lake Agassiz/Ojibway and a resulting reduced strength of North Atlantic thermohaline circulation), several key questions remain unanswered. One salient aspect concerns the total amount of freshwater released during this catastrophic event, likely echoed by a near‐instantaneous eustatic sea‐level rise. So far, no attempts have been made to perform high‐resolution sea‐level studies that explicitly focus on this critical time interval. Here, we present new data from the Mississippi Delta suggestive of abrupt sea‐level rise associated with the 8.2 ka event. However, the amount of sea‐level rise was likely less than ∼1.2 m, corresponding to a meltwater volume of less than ∼4.3 10 14 m 3; values lower than estimates used by several recent studies.",
    url = "https://doi.org/10.1029/2004gl021429",
    doi = "10.1029/2004gl021429",
    openalex = "W1492422926",
    references = "doi101007bf00379369"
}

▪ Abstract Avulsion is the natural process by which flow diverts out of an established river channel into a new permanent course on the adjacent floodplain. Avulsions are primarily features of aggrading floodplains. Their recurrence interval varies widely among the few modern rivers for which such data exist, ranging from as low as 28 years for the Kosi River (India) to up to 1400 years for the Mississippi. Avulsions cause loss of life, property damage, destabilization of shipping and irrigation channels, and even coastal erosion as sediment is temporarily sequestered on the floodplain. They are also the main process that builds alluvial stratigraphy. Their causes remain relatively unknown, but stability analyses of bifurcating channels suggest that thresholds in the relative energy slope and Shields parameter of the bifurcating channel system are key factors.

@article{doi101146annurevearth32101802120201,
    author = "Slingerland, Rudy and Smith, Norman D.",
    title = "RIVER AVULSIONS AND THEIR DEPOSITS",
    year = "2004",
    journal = "Annual Review of Earth and Planetary Sciences",
    abstract = "▪ Abstract Avulsion is the natural process by which flow diverts out of an established river channel into a new permanent course on the adjacent floodplain. Avulsions are primarily features of aggrading floodplains. Their recurrence interval varies widely among the few modern rivers for which such data exist, ranging from as low as 28 years for the Kosi River (India) to up to 1400 years for the Mississippi. Avulsions cause loss of life, property damage, destabilization of shipping and irrigation channels, and even coastal erosion as sediment is temporarily sequestered on the floodplain. They are also the main process that builds alluvial stratigraphy. Their causes remain relatively unknown, but stability analyses of bifurcating channels suggest that thresholds in the relative energy slope and Shields parameter of the bifurcating channel system are key factors.",
    url = "https://doi.org/10.1146/annurev.earth.32.101802.120201",
    doi = "10.1146/annurev.earth.32.101802.120201",
    openalex = "W2139920049",
    references = "doi101002sici10969837199603213217aidesp61130co2u, doi101016001282527990059x, doi1010160037073869900104, doi101016s0012825200000386, doi101017s0022112081000451, doi101111j136530911965tb01561x, doi101111j136530911979tb00935x, doi101111j136530911989tb00817x, doi102307211375, doi10230740027956, flint1947geological"
}

Five representative areas of the Mississippi River delta plain were investigated using remote images, marsh elevations, water depths, sediment cores, and radiocarbon dates to estimate the timing, magnitudes, and relative rates of marsh erosion and land subsidence at geological and historical time scales.

@article{doi103133ofr20051216,
    author = "Morton, Robert A. and Bernier, Julie C. and Barras, John A. and Ferina, Nicholas F.",
    title = "Rapid subsidence and historical wetland loss in the Mississippi Delta Plain: Likely causes and future implications",
    year = "2005",
    journal = "Antarctica A Keystone in a Changing World",
    abstract = "Five representative areas of the Mississippi River delta plain were investigated using remote images, marsh elevations, water depths, sediment cores, and radiocarbon dates to estimate the timing, magnitudes, and relative rates of marsh erosion and land subsidence at geological and historical time scales.",
    url = "https://doi.org/10.3133/ofr20051216",
    doi = "10.3133/ofr20051216",
    openalex = "W1548702358",
    references = "doi101007bf00379369, doi101007bf02691346, doi1010160040195174900730, doi101016s0967065397885754, doi101086623352, doi101130reg2p187, doi101306eg04040302007, doi105724gcs91120034, openalexw1586892756, openalexw1592594904"
}

Large deltas are commonly believed to exhibit rapid rates of tectonic subsidence, largely due to sediment loading of the lithosphere. As a result, deltaic plains are prone to accelerated relative sea-level rise, coastal erosion, and wetland loss. Hurricane Katrina's devastation testifies to the severe threat that these processes pose to the Mississippi Delta, but the relative role of tectonics versus other mechanisms causing land subsidence remains elusive. Relative sea-level records derived from basal peat have the potential to quantify differential crustal movements over Holocene time scales with exceptionally high accuracy and precision. Here we present new sea-level index points from two study areas in the southwestern Mississippi Delta that essentially coincide with a recently published detailed relative sea-level record from the eastern part of the delta. Our results show that differential vertical movements among the three study areas have been only ∼0.1 mm yr−1. We compare our evidence with a recent sea-level compilation from the Caribbean, to a large extent based on data from areas that are tectonically stable. Our sea-level index points nearly coincide with the Caribbean data, showing surprising tectonic stability for considerable sections of the Mississippi Delta. However, the well-documented high subsidence rates in and near the birdfoot of the Mississippi Delta indicate that different conditions prevail there. The rapid wetland loss in coastal Louisiana is likely due, to a considerable extent, to the compaction of Holocene strata.

@article{doi101130g226241,
    author = "Törnqvist, Torbjörn E. and Bick, Scott J. and van der Borg, Klaas and de Jong, Arie F. M.",
    title = "How stable is the Mississippi Delta?",
    year = "2006",
    journal = "Geology",
    abstract = "Large deltas are commonly believed to exhibit rapid rates of tectonic subsidence, largely due to sediment loading of the lithosphere. As a result, deltaic plains are prone to accelerated relative sea-level rise, coastal erosion, and wetland loss. Hurricane Katrina's devastation testifies to the severe threat that these processes pose to the Mississippi Delta, but the relative role of tectonics versus other mechanisms causing land subsidence remains elusive. Relative sea-level records derived from basal peat have the potential to quantify differential crustal movements over Holocene time scales with exceptionally high accuracy and precision. Here we present new sea-level index points from two study areas in the southwestern Mississippi Delta that essentially coincide with a recently published detailed relative sea-level record from the eastern part of the delta. Our results show that differential vertical movements among the three study areas have been only ∼0.1 mm yr−1. We compare our evidence with a recent sea-level compilation from the Caribbean, to a large extent based on data from areas that are tectonically stable. Our sea-level index points nearly coincide with the Caribbean data, showing surprising tectonic stability for considerable sections of the Mississippi Delta. However, the well-documented high subsidence rates in and near the birdfoot of the Mississippi Delta indicate that different conditions prevail there. The rapid wetland loss in coastal Louisiana is likely due, to a considerable extent, to the compaction of Holocene strata.",
    url = "https://doi.org/10.1130/g22624.1",
    doi = "10.1130/g22624.1",
    openalex = "W2116950448",
    references = "doi101007bf00379369, doi101306eg04040302007"
}

The morphology of an alluvial river channel is the consequence of sediment transport and sedimentation in the river. Morphological style is determined chiefly by the caliber and quantity of sediment delivered to the channel, although modulated by channel scale. Yet the relations between sediment transport and river morphology have received only limited, qualitative attention. In this review, the problem is studied by defining sediment transport regimes on the basis of the Shields number, a nondimensional measure of the capacity of the channel to move sediment of a given caliber. The problem is also approached from an inverse perspective by which the quantity and character of sediment deposits are used to infer details about the variation of sediment transport and sedimentation along a channel. Coupling the two approaches establishes a basis to gain new insights into the origins of alluvial channel morphology.

@article{doi101146annurevearth33092203122721,
    author = "Church, Michael",
    title = "BED MATERIAL TRANSPORT AND THE MORPHOLOGY OF ALLUVIAL RIVER CHANNELS",
    year = "2006",
    journal = "Annual Review of Earth and Planetary Sciences",
    abstract = "The morphology of an alluvial river channel is the consequence of sediment transport and sedimentation in the river. Morphological style is determined chiefly by the caliber and quantity of sediment delivered to the channel, although modulated by channel scale. Yet the relations between sediment transport and river morphology have received only limited, qualitative attention. In this review, the problem is studied by defining sediment transport regimes on the basis of the Shields number, a nondimensional measure of the capacity of the channel to move sediment of a given caliber. The problem is also approached from an inverse perspective by which the quantity and character of sediment deposits are used to infer details about the variation of sediment transport and sedimentation along a channel. Coupling the two approaches establishes a basis to gain new insights into the origins of alluvial channel morphology.",
    url = "https://doi.org/10.1146/annurev.earth.33.092203.122721",
    doi = "10.1146/annurev.earth.33.092203.122721",
    openalex = "W2101354433",
    references = "doi101016001282527990059x, doi1010160169555x9290039q, openalexw602333724"
}

Abstract Using modern and ancient examples we show that river-dominated deltas formed in shallow basins have multiple coeval terminal distributary channels at different scales. Sediment dispersion through multiple terminal distributary channels results in an overall lobate shape of the river-dominated delta that is opposite to the digitate Mississippi type, but similar with deltas described as wave-dominated. The examples of deltas that we present show typical coarsening-upward delta-front facies successions but do not contain deep distributary channels, as have been routinely interpreted in many ancient deltas. We show that shallow-water river-dominated delta-front deposits are typically capped by small terminal distributary channels, the cross-sectional area of which represents a small fraction of the main fluvial trunk channel. Recognizing terminal distributary channels is critical in interpretation of river-dominated deltas. Terminal distributary channels are the most distal channelized features and can be both subaerial and subaqueous. Their dimensions vary between tens of meters to kilometers in width, with common values of 100–400 m and depths of 1–3 m, and are rarely incised. The orientation of the terminal distributary channels for the same system has a large variation, with values between 123° (Volga Delta) and 248° (Lena Delta). Terminal distributary channels are intimately associated with mouth-bar deposits and are infilled by aggradation and lateral or upstream migration of the mouth bars. Deposits of terminal distributary channels have characteristic sedimentary structures of unidirectional effluent flow but also show evidence of reworking by waves and tides.

@article{doi102110jsr2006026,
    author = "Olariu, Cornel and Bhattacharya, Janok P.",
    title = "Terminal Distributary Channels and Delta Front Architecture of River-Dominated Delta Systems",
    year = "2006",
    journal = "Journal of Sedimentary Research",
    abstract = "Abstract Using modern and ancient examples we show that river-dominated deltas formed in shallow basins have multiple coeval terminal distributary channels at different scales. Sediment dispersion through multiple terminal distributary channels results in an overall lobate shape of the river-dominated delta that is opposite to the digitate Mississippi type, but similar with deltas described as wave-dominated. The examples of deltas that we present show typical coarsening-upward delta-front facies successions but do not contain deep distributary channels, as have been routinely interpreted in many ancient deltas. We show that shallow-water river-dominated delta-front deposits are typically capped by small terminal distributary channels, the cross-sectional area of which represents a small fraction of the main fluvial trunk channel. Recognizing terminal distributary channels is critical in interpretation of river-dominated deltas. Terminal distributary channels are the most distal channelized features and can be both subaerial and subaqueous. Their dimensions vary between tens of meters to kilometers in width, with common values of 100–400 m and depths of 1–3 m, and are rarely incised. The orientation of the terminal distributary channels for the same system has a large variation, with values between 123° (Volga Delta) and 248° (Lena Delta). Terminal distributary channels are intimately associated with mouth-bar deposits and are infilled by aggradation and lateral or upstream migration of the mouth bars. Deposits of terminal distributary channels have characteristic sedimentary structures of unidirectional effluent flow but also show evidence of reworking by waves and tides.",
    url = "https://doi.org/10.2110/jsr.2006.026",
    doi = "10.2110/jsr.2006.026",
    openalex = "W2132272817",
    references = "doi101306111302730367, doi1013065ceadd7616bb11d78645000102c1865d, openalexw101633874, openalexw1558464430, openalexw1592594904"
}

Abstract The three-dimensional geometry of fluvial channel bodies and valley fills has received much less attention than their internal structure, despite the fact that many subsurface analyses draw upon the geometry of suitable fluvial analogues. Although channel-body geometry has been widely linked to base-level change and accommodation, few studies have evaluated the influence of local geomorphic controls. To remedy these deficiencies, we review the terminology for describing channel-body geometry, and present a literature dataset that represents more than 1500 bedrock and Quaternary fluvial bodies for which width (W) and thickness (T) are recorded. Twelve types of channel bodies and valley fills are distinguished based on their geomorphic setting, geometry, and internal structure, and log-log plots of W against T are presented for each type. Narrow and broad ribbons (W/T 1000, respectively) are distinguished. The dataset allows an informed selection of analogues for subsurface applications, and spreadsheets and graphs can be downloaded from a data repository. Mobile-channel belts are mainly the deposits of braided and low-sinuosity rivers, which may exceed 1 km in composite thickness and 1300 km in width. Their overwhelming dominance throughout geological time reflects their link to tectonic activity, exhumation events, and high sediment supply. Some deposits that rest on flat-lying bedrock unconformities cover areas > 70,000 km2. In contrast, meandering river bodies in the dataset are < 38 m thick and < 15 km wide, and the organized flow conditions necessary for their development may have been unusual. They do not appear to have built basin-scale deposits. Fixed channels and poorly channelized systems are divided into distributary systems (channels on megafans, deltas, and distal alluvial fans, and in crevasse systems and avulsion deposits), through-going rivers, and channels in eolian settings. Because width/maximum depth of many modern alluvial channels is between 5 and 15, these bodies probably record an initial aspect ratio followed by modest widening prior to filling or avulsion. The narrow form (W/T typically < 15) commonly reflects bank resistance and rapid filling, although some are associated with base-level rise. Exceptionally narrow bodies (W/T locally < 1) may additionally reflect unusually deep incision, compactional thickening, filling by mass-flow deposits, balanced aggradation of natural levees and channels, thawing of frozen substrates, and channel reoccupation. Valley fills rest on older bedrock or represent a brief hiatus within marine and alluvial successions. Many bedrock valley fills have W/T < 20 due to deep incision along tectonic lineaments and stacking along faults. Within marine and alluvial strata, upper Paleozoic valley fills appear larger than Mesozoic examples, possibly reflecting the influence of large glacioeustatic fluctuations in the Paleozoic. Valley fills in sub-glacial and proglacial settings are relatively narrow (W/T as low as 2.5) due to incision from catastrophic meltwater flows. The overlap in dimensions between channel bodies and valley fills, as identified by the original authors, suggests that many braided and meandering channel bodies in the rock record occupy paleovalleys. Modeling has emphasized the importance of avulsion frequency, sedimentation rate, and the ratio of channel belt and floodplain width in determining channel-body connectedness. Although these controls strongly influence mobile channel belts, they are less effective in fixed-channel systems, for which many database examples testify to the influence of local geomorphic factors that include bank strength and channel aggradation. The dataset contains few examples of highly connected suites of fixed-channel bodies, despite their abundance in many formations. Whereas accommodation is paramount for preservation, its influence is mediated through geomorphic factors, thus complicating inferences about base-level controls.

@article{doi102110jsr2006060,
    author = "Gibling, Martin R.",
    title = "Width and Thickness of Fluvial Channel Bodies and Valley Fills in the Geological Record: A Literature Compilation and Classification",
    year = "2006",
    journal = "Journal of Sedimentary Research",
    abstract = "Abstract The three-dimensional geometry of fluvial channel bodies and valley fills has received much less attention than their internal structure, despite the fact that many subsurface analyses draw upon the geometry of suitable fluvial analogues. Although channel-body geometry has been widely linked to base-level change and accommodation, few studies have evaluated the influence of local geomorphic controls. To remedy these deficiencies, we review the terminology for describing channel-body geometry, and present a literature dataset that represents more than 1500 bedrock and Quaternary fluvial bodies for which width (W) and thickness (T) are recorded. Twelve types of channel bodies and valley fills are distinguished based on their geomorphic setting, geometry, and internal structure, and log-log plots of W against T are presented for each type. Narrow and broad ribbons (W/T 1000, respectively) are distinguished. The dataset allows an informed selection of analogues for subsurface applications, and spreadsheets and graphs can be downloaded from a data repository. Mobile-channel belts are mainly the deposits of braided and low-sinuosity rivers, which may exceed 1 km in composite thickness and 1300 km in width. Their overwhelming dominance throughout geological time reflects their link to tectonic activity, exhumation events, and high sediment supply. Some deposits that rest on flat-lying bedrock unconformities cover areas > 70,000 km2. In contrast, meandering river bodies in the dataset are < 38 m thick and < 15 km wide, and the organized flow conditions necessary for their development may have been unusual. They do not appear to have built basin-scale deposits. Fixed channels and poorly channelized systems are divided into distributary systems (channels on megafans, deltas, and distal alluvial fans, and in crevasse systems and avulsion deposits), through-going rivers, and channels in eolian settings. Because width/maximum depth of many modern alluvial channels is between 5 and 15, these bodies probably record an initial aspect ratio followed by modest widening prior to filling or avulsion. The narrow form (W/T typically < 15) commonly reflects bank resistance and rapid filling, although some are associated with base-level rise. Exceptionally narrow bodies (W/T locally < 1) may additionally reflect unusually deep incision, compactional thickening, filling by mass-flow deposits, balanced aggradation of natural levees and channels, thawing of frozen substrates, and channel reoccupation. Valley fills rest on older bedrock or represent a brief hiatus within marine and alluvial successions. Many bedrock valley fills have W/T < 20 due to deep incision along tectonic lineaments and stacking along faults. Within marine and alluvial strata, upper Paleozoic valley fills appear larger than Mesozoic examples, possibly reflecting the influence of large glacioeustatic fluctuations in the Paleozoic. Valley fills in sub-glacial and proglacial settings are relatively narrow (W/T as low as 2.5) due to incision from catastrophic meltwater flows. The overlap in dimensions between channel bodies and valley fills, as identified by the original authors, suggests that many braided and meandering channel bodies in the rock record occupy paleovalleys. Modeling has emphasized the importance of avulsion frequency, sedimentation rate, and the ratio of channel belt and floodplain width in determining channel-body connectedness. Although these controls strongly influence mobile channel belts, they are less effective in fixed-channel systems, for which many database examples testify to the influence of local geomorphic factors that include bank strength and channel aggradation. The dataset contains few examples of highly connected suites of fixed-channel bodies, despite their abundance in many formations. Whereas accommodation is paramount for preservation, its influence is mediated through geomorphic factors, thus complicating inferences about base-level controls.",
    url = "https://doi.org/10.2110/jsr.2006.060",
    doi = "10.2110/jsr.2006.060",
    openalex = "W2113298788",
    references = "doi1010079783662032374, doi1010160012825285900017, doi1010160037073878900027, doi1010160037073884900745, doi1010160169555x9290039q, doi1010160341816294900019, doi101016s003707380100118x, doi101029jd092id07p08411, doi101046j13653091200000008x, doi101086626637, doi101111j136530911989tb00817x, doi10113000167606194556275edosat20co2, doi101144gsjgs13610039, doi101306703c8f01170711d78645000102c1865d, doi102110csp9907, doi102110jsr69800, doi102307211375, flint1947geological, openalexw2094255421"
}

Hurricanes Katrina and Rita showed the vulnerability of coastal communities and how human activities that caused deterioration of the Mississippi Deltaic Plain (MDP) exacerbated this vulnerability. The MDP formed by dynamic interactions between river and coast at various temporal and spatial scales, and human activity has reduced these interactions at all scales. Restoration efforts aim to re-establish this dynamic interaction, with emphasis on reconnecting the river to the deltaic plain. Science must guide MDP restoration, which will provide insights into delta restoration elsewhere and generally into coasts facing climate change in times of resource scarcity.

@article{doi101126science1137030,
    author = "Day, John W. and Boesch, Donald F. and Clairain, Ellis J. and Kemp, G. Paul and Laska, Shirley and Mitsch, William J. and Orth, Kenneth and Mashriqui, Hassan and Reed, Denise J. and Shabman, Leonard and Simenstad, Charles A. and Streever, Bill and Twilley, Robert R. and Watson, Chester C. and Wells, John T. and Whigham, Dennis F.",
    title = "Restoration of the Mississippi Delta: Lessons from Hurricanes Katrina and Rita",
    year = "2007",
    journal = "Science",
    abstract = "Hurricanes Katrina and Rita showed the vulnerability of coastal communities and how human activities that caused deterioration of the Mississippi Deltaic Plain (MDP) exacerbated this vulnerability. The MDP formed by dynamic interactions between river and coast at various temporal and spatial scales, and human activity has reduced these interactions at all scales. Restoration efforts aim to re-establish this dynamic interaction, with emphasis on reconnecting the river to the deltaic plain. Science must guide MDP restoration, which will provide insights into delta restoration elsewhere and generally into coasts facing climate change in times of resource scarcity.",
    url = "https://doi.org/10.1126/science.1137030",
    doi = "10.1126/science.1137030",
    openalex = "W2126231593",
    references = "doi101016s0967065397885973, doi101126science1129116, doi105724gcs91120034, openalexw1846023905"
}

Corn cultivation in the United States is expected to increase to meet demand for ethanol. Nitrogen leaching from fertilized corn fields to the Mississippi-Atchafalaya River system is a primary cause of the bottom-water hypoxia that develops on the continental shelf of the northern Gulf of Mexico each summer. In this study, we combine agricultural land use scenarios with physically based models of terrestrial and aquatic nitrogen to examine the effect of present and future expansion of corn-based ethanol production on nitrogen export by the Mississippi and Atchafalaya Rivers to the Gulf of Mexico. The results show that the increase in corn cultivation required to meet the goal of 15-36 billion gallons of renewable fuels by the year 2022 suggested by a recent U.S. Senate energy policy would increase the annual average flux of dissolved inorganic nitrogen (DIN) export by the Mississippi and Atchafalaya Rivers by 10-34%. Generating 15 billion gallons of corn-based ethanol by the year 2022 will increase the odds that annual DIN export exceeds the target set for reducing hypoxia in the Gulf of Mexico to >95%. Examination of extreme mitigation options shows that expanding corn-based ethanol production would make the already difficult challenges of reducing nitrogen export to the Gulf of Mexico and the extent of hypoxia practically impossible without large shifts in food production and agricultural management.

@article{doi101073pnas0708300105,
    author = "Donner, Simon D. and Kucharik, Christopher J.",
    title = "Corn-based ethanol production compromises goal of reducing nitrogen export by the Mississippi River",
    year = "2008",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = "Corn cultivation in the United States is expected to increase to meet demand for ethanol. Nitrogen leaching from fertilized corn fields to the Mississippi-Atchafalaya River system is a primary cause of the bottom-water hypoxia that develops on the continental shelf of the northern Gulf of Mexico each summer. In this study, we combine agricultural land use scenarios with physically based models of terrestrial and aquatic nitrogen to examine the effect of present and future expansion of corn-based ethanol production on nitrogen export by the Mississippi and Atchafalaya Rivers to the Gulf of Mexico. The results show that the increase in corn cultivation required to meet the goal of 15-36 billion gallons of renewable fuels by the year 2022 suggested by a recent U.S. Senate energy policy would increase the annual average flux of dissolved inorganic nitrogen (DIN) export by the Mississippi and Atchafalaya Rivers by 10-34\%. Generating 15 billion gallons of corn-based ethanol by the year 2022 will increase the odds that annual DIN export exceeds the target set for reducing hypoxia in the Gulf of Mexico to >95\%. Examination of extreme mitigation options shows that expanding corn-based ethanol production would make the already difficult challenges of reducing nitrogen export to the Gulf of Mexico and the extent of hypoxia practically impossible without large shifts in food production and agricultural management.",
    url = "https://doi.org/10.1073/pnas.0708300105",
    doi = "10.1073/pnas.0708300105",
    openalex = "W1983984469",
    references = "doi101016s004896979900532x"
}

@article{doi101016jjhydrol201004001,
    author = "Allison, Mead A. and Meselhe, Ehab",
    title = "The use of large water and sediment diversions in the lower Mississippi River (Louisiana) for coastal restoration",
    year = "2010",
    journal = "Journal of Hydrology",
    url = "https://doi.org/10.1016/j.jhydrol.2010.04.001",
    doi = "10.1016/j.jhydrol.2010.04.001",
    openalex = "W2005660697",
    references = "doi101002hyp7477, doi1010292009eo420001, doi101038ngeo129, doi101038ngeo553, doi101073pnas0812878106, doi10108004353676198711880207, doi101086628741, doi101086629606, doi101126science1109454, doi101126science1135456, doi101126science1137030, doi101306eg04040302007, doi1023071353136, openalexw1846023905"
}

An integrated modeling approach was used to connect socioeconomic factors and nutrient management to river export of nitrogen, phosphorus, silica and carbon based on an updated Global NEWS model. Past trends (1970–2000) and four future scenarios were analyzed. Differences among the scenarios for nutrient management in agriculture were a key factor affecting the magnitude and direction of change of future DIN river export. In contrast, connectivity and level of sewage treatment and P detergent use were more important for differences in DIP river export. Global particulate nutrient export was calculated to decrease for all scenarios, in part due to increases in dams for hydropower. Small changes in dissolved silica and dissolved organics were calculated for all scenarios at the global scale. Population changes were an important underlying factor for river export of all nutrients in all scenarios. Substantial regional differences were calculated for all nutrient elements and forms. South Asia alone accounted for over half of the global increase in DIN and DIP river export between 1970 and 2000 and in the subsequent 30 years under the Global Orchestration scenario (globally connected with reactive approach to environmental problems); DIN river export decreased in the Adapting Mosaic (globally connected with proactive approach) scenario by 2030, although DIP continued to increase. Risks for coastal eutrophication will likely continue to increase in many world regions for the foreseeable future due to both increases in magnitude and changes in nutrient ratios in river export.

@article{doi1010292009gb003587,
    author = "Seitzinger, Sybil P. and Mayorga, Emilio and Bouwman, Lex and Kroeze, Carolien and Beusen, Arthur and Billen, Gilles and Drecht, G. Van and Dumont, Egon and Fekete, B M and Garnier, Josette and Harrison, John A.",
    title = "Global river nutrient export: A scenario analysis of past and future trends",
    year = "2010",
    journal = "Global Biogeochemical Cycles",
    abstract = "An integrated modeling approach was used to connect socioeconomic factors and nutrient management to river export of nitrogen, phosphorus, silica and carbon based on an updated Global NEWS model. Past trends (1970–2000) and four future scenarios were analyzed. Differences among the scenarios for nutrient management in agriculture were a key factor affecting the magnitude and direction of change of future DIN river export. In contrast, connectivity and level of sewage treatment and P detergent use were more important for differences in DIP river export. Global particulate nutrient export was calculated to decrease for all scenarios, in part due to increases in dams for hydropower. Small changes in dissolved silica and dissolved organics were calculated for all scenarios at the global scale. Population changes were an important underlying factor for river export of all nutrients in all scenarios. Substantial regional differences were calculated for all nutrient elements and forms. South Asia alone accounted for over half of the global increase in DIN and DIP river export between 1970 and 2000 and in the subsequent 30 years under the Global Orchestration scenario (globally connected with reactive approach to environmental problems); DIN river export decreased in the Adapting Mosaic (globally connected with proactive approach) scenario by 2030, although DIP continued to increase. Risks for coastal eutrophication will likely continue to increase in many world regions for the foreseeable future due to both increases in magnitude and changes in nutrient ratios in river export.",
    url = "https://doi.org/10.1029/2009gb003587",
    doi = "10.1029/2009gb003587",
    openalex = "W2117742717",
    references = "doi1010292008gb003281"
}

Restoration of river deltas involves diverting sediment and water from major channels into adjoining drowned areas, where the sediment can build new land and provide a platform for regenerating wetland ecosystems. Except for local engineered structures at the points of diversion, restoration mainly relies on natural delta-building processes. Present understanding of such processes is sufficient to provide a basis for determining the feasibility of restoration projects through quantitative estimates of land-building rates and sustainable wetland area under different scenarios of sediment supply, subsidence, and sea-level rise. We are not yet to the point of being able to predict the evolution of a restored delta in detail. Predictions of delta evolution are based on field studies of active deltas, deltas in mine-tailings ponds, experimental deltas, and countless natural experiments contained in the stratigraphic record. These studies provide input for a variety of mechanistic delta models, ranging from radially averaged formulations to more detailed models that can resolve channels, topography, and ecosystem processes. Especially exciting areas for future research include understanding the mechanisms by which deltaic channel networks self-organize, grow, and distribute sediment and nutrients over the delta surface and coupling these to ecosystem processes, especially the interplay of topography, network geometry, and ecosystem dynamics.

@article{doi101146annurevmarine120709142856,
    author = "Paola, Chris and Twilley, Robert R. and Edmonds, Douglas A. and Kim, W. and Mohrig, David and Parker, Gary and Viparelli, E. and Voller, Vaughan R.",
    title = "Natural Processes in Delta Restoration: Application to the Mississippi Delta",
    year = "2010",
    journal = "Annual Review of Marine Science",
    abstract = "Restoration of river deltas involves diverting sediment and water from major channels into adjoining drowned areas, where the sediment can build new land and provide a platform for regenerating wetland ecosystems. Except for local engineered structures at the points of diversion, restoration mainly relies on natural delta-building processes. Present understanding of such processes is sufficient to provide a basis for determining the feasibility of restoration projects through quantitative estimates of land-building rates and sustainable wetland area under different scenarios of sediment supply, subsidence, and sea-level rise. We are not yet to the point of being able to predict the evolution of a restored delta in detail. Predictions of delta evolution are based on field studies of active deltas, deltas in mine-tailings ponds, experimental deltas, and countless natural experiments contained in the stratigraphic record. These studies provide input for a variety of mechanistic delta models, ranging from radially averaged formulations to more detailed models that can resolve channels, topography, and ecosystem processes. Especially exciting areas for future research include understanding the mechanisms by which deltaic channel networks self-organize, grow, and distribute sediment and nutrients over the delta surface and coupling these to ecosystem processes, especially the interplay of topography, network geometry, and ecosystem dynamics.",
    url = "https://doi.org/10.1146/annurev-marine-120709-142856",
    doi = "10.1146/annurev-marine-120709-142856",
    openalex = "W2129668185",
    references = "doi101007s1162500800433, doi101016jearscirev200906008, doi101016s0967065397885973, doi1010292008wr007382, doi1010292009eo420001, doi101038ngeo553, doi101038ngeo629, doi101038ngeo730, doi101061asce07339429199812410985, doi101126science1109769, doi101126science1137030, doi101146annurevmarine120308081105, doi1016410006356820010510373rnlttg20co2, doi1018901051076120060162091mfmdda20co2, doi102110jsr2009070, doi1023071353283, doi102307211375, doi103133ofr20051216, flint1947geological, openalexw1604095676, openalexw1846023905, openalexw1852367402, openalexw2255943944, openalexw645095896"
}

Rivers self-organize their pattern/planform through feedbacks between bars, channels, floodplain and vegetation, which emerge as a result of the basic spatial sorting process of wash load sediment and bed sediment. The balance between floodplain formation and destruction determines the width and pattern of channels. Floodplain structure affects the style and rate of channel avulsion once aggradation takes place. Downstream fining of bed sediment and the sediment balance of fines in the pores of the bed sediment provide the ‘template’ or sediment boundary conditions, from which sorting at smaller scales leads to the formation of distinct channel patterns. Bar patterns provide the template of bank erosion and formation as well as the dynamics of the channel network through bifurcation destabilization. However, so far we have been unable to obtain dynamic meandering in laboratory experiments and in physics-based models that can also produce braiding, which reflects our lack of understanding of what causes the different river patterns.

@article{doi1011770309133310365300,
    author = "Kleinhans, Maarten G.",
    title = "Sorting out river channel patterns",
    year = "2010",
    journal = "Progress in Physical Geography Earth and Environment",
    abstract = "Rivers self-organize their pattern/planform through feedbacks between bars, channels, floodplain and vegetation, which emerge as a result of the basic spatial sorting process of wash load sediment and bed sediment. The balance between floodplain formation and destruction determines the width and pattern of channels. Floodplain structure affects the style and rate of channel avulsion once aggradation takes place. Downstream fining of bed sediment and the sediment balance of fines in the pores of the bed sediment provide the ‘template’ or sediment boundary conditions, from which sorting at smaller scales leads to the formation of distinct channel patterns. Bar patterns provide the template of bank erosion and formation as well as the dynamics of the channel network through bifurcation destabilization. However, so far we have been unable to obtain dynamic meandering in laboratory experiments and in physics-based models that can also produce braiding, which reflects our lack of understanding of what causes the different river patterns.",
    url = "https://doi.org/10.1177/0309133310365300",
    doi = "10.1177/0309133310365300",
    openalex = "W2165317498",
    references = "doi101016jquascirev200707013, doi101046j13652117200100150x, doi101061asce07339429199812410985, doi101146annurevearth32101802120201"
}

The Mississippi Delta has long been characterized as an area of rapid subsidence; however, recent subsidence rates are substantially lower than previously reported. Tide-gauge records indicate that rates of relative sea-level rise were slow from 1947 until the mid-1960s, relatively fast from the mid-1960s until the early 1990s, and then slow since the early 1990s. These trends and rates are independently verified by repeat benchmark surveys and height monitoring at continuously operating geographic positioning system stations. Subsidence rates for the slow periods were a few millimeters per year, comparable to rates averaged over geological time scales that are attributed to natural processes such as shallow sediment compaction and deep crustal loading. The decadal pattern of slow, then rapid, then slow subsidence may be caused by natural deep-basin processes (e.g., gravity gliding and salt migration), but it is more likely related to rates of hydrocarbon production that followed the same temporal trends. If accelerated subsidence was primarily induced by reservoir compaction and fault reactivation associated with fluid withdrawal that also accelerated in the 1960s and 1970s, then the recent reductions in subsidence rates likely reflect a balancing of subsurface stresses and a return to near preproduction conditions.

@article{doi102112jcoastresd0900014r11,
    author = "Morton, Robert A. and Bernier, Julie C.",
    title = "Recent Subsidence-Rate Reductions in the Mississippi Delta and Their Geological Implications",
    year = "2010",
    journal = "Journal of Coastal Research",
    abstract = "The Mississippi Delta has long been characterized as an area of rapid subsidence; however, recent subsidence rates are substantially lower than previously reported. Tide-gauge records indicate that rates of relative sea-level rise were slow from 1947 until the mid-1960s, relatively fast from the mid-1960s until the early 1990s, and then slow since the early 1990s. These trends and rates are independently verified by repeat benchmark surveys and height monitoring at continuously operating geographic positioning system stations. Subsidence rates for the slow periods were a few millimeters per year, comparable to rates averaged over geological time scales that are attributed to natural processes such as shallow sediment compaction and deep crustal loading. The decadal pattern of slow, then rapid, then slow subsidence may be caused by natural deep-basin processes (e.g., gravity gliding and salt migration), but it is more likely related to rates of hydrocarbon production that followed the same temporal trends. If accelerated subsidence was primarily induced by reservoir compaction and fault reactivation associated with fluid withdrawal that also accelerated in the 1960s and 1970s, then the recent reductions in subsidence rates likely reflect a balancing of subsurface stresses and a return to near preproduction conditions.",
    url = "https://doi.org/10.2112/jcoastres-d-09-00014r1.1",
    doi = "10.2112/jcoastres-d-09-00014r1.1",
    openalex = "W2001542002",
    references = "doi1010160040195174900730, doi101306eg04040302007"
}

Riverine nitrate N in the Mississippi River leads to hypoxia in the Gulf of Mexico. Several recent modeling studies estimated major N inputs and suggested source areas that could be targeted for conservation programs. We conducted a similar analysis with more recent and extensive data that demonstrates the importance of hydrology in controlling the percentage of net N inputs (NNI) exported by rivers. The average fraction of annual riverine nitrate N export/NNI ranged from 0.05 for the lower Mississippi subbasin to 0.3 for the upper Mississippi River basin and as high as 1.4 (4.2 in a wet year) for the Embarras River watershed, a mostly tile-drained basin. Intensive corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] watersheds on Mollisols had low NNI values and when combined with riverine N losses suggest a net depletion of soil organic N. We used county-level data to develop a nonlinear model ofN inputs and landscape factors that were related to winter-spring riverine nitrate yields for 153 watersheds within the basin. We found that river runoff times fertilizer N input was the major predictive term, explaining 76% of the variation in the model. Fertilizer inputs were highly correlated with fraction of land area in row crops. Tile drainage explained 17% of the spatial variation in winter-spring nitrate yield, whereas human consumption of N (i.e., sewage effluent) accounted for 7%. Net N inputs were not a good predictor of riverine nitrate N yields, nor were other N balances. We used this model to predict the expected nitrate N yield from each county in the Mississippi River basin; the greatest nitrate N yields corresponded to the highly productive, tile-drained cornbelt from southwest Minnesota across Iowa, Illinois, Indiana, and Ohio. This analysis can be used to guide decisions about where efforts to reduce nitrate N losses can be most effectively targeted to improve local water quality and reduce export to the Gulf of Mexico.

@article{doi102134jeq20100115,
    author = "David, Mark B. and Drinkwater, Laurie E. and McIsaac, Gregory F.",
    title = "Sources of Nitrate Yields in the Mississippi River Basin",
    year = "2010",
    journal = "Journal of Environmental Quality",
    abstract = "Riverine nitrate N in the Mississippi River leads to hypoxia in the Gulf of Mexico. Several recent modeling studies estimated major N inputs and suggested source areas that could be targeted for conservation programs. We conducted a similar analysis with more recent and extensive data that demonstrates the importance of hydrology in controlling the percentage of net N inputs (NNI) exported by rivers. The average fraction of annual riverine nitrate N export/NNI ranged from 0.05 for the lower Mississippi subbasin to 0.3 for the upper Mississippi River basin and as high as 1.4 (4.2 in a wet year) for the Embarras River watershed, a mostly tile-drained basin. Intensive corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] watersheds on Mollisols had low NNI values and when combined with riverine N losses suggest a net depletion of soil organic N. We used county-level data to develop a nonlinear model ofN inputs and landscape factors that were related to winter-spring riverine nitrate yields for 153 watersheds within the basin. We found that river runoff times fertilizer N input was the major predictive term, explaining 76\% of the variation in the model. Fertilizer inputs were highly correlated with fraction of land area in row crops. Tile drainage explained 17\% of the spatial variation in winter-spring nitrate yield, whereas human consumption of N (i.e., sewage effluent) accounted for 7\%. Net N inputs were not a good predictor of riverine nitrate N yields, nor were other N balances. We used this model to predict the expected nitrate N yield from each county in the Mississippi River basin; the greatest nitrate N yields corresponded to the highly productive, tile-drained cornbelt from southwest Minnesota across Iowa, Illinois, Indiana, and Ohio. This analysis can be used to guide decisions about where efforts to reduce nitrate N losses can be most effectively targeted to improve local water quality and reduce export to the Gulf of Mexico.",
    url = "https://doi.org/10.2134/jeq2010.0115",
    doi = "10.2134/jeq2010.0115",
    openalex = "W2049720706",
    references = "doi101890080085"
}

Changes in nitrate concentration and flux between 1980 and 2008 at eight sites in the Mississippi River basin were determined using a new statistical method that accommodates evolving nitrate behavior over time and produces flow-normalized estimates of nitrate concentration and flux that are independent of random variations in streamflow. The results show that little consistent progress has been made in reducing riverine nitrate since 1980, and that flow-normalized concentration and flux are increasing in some areas. Flow-normalized nitrate concentration and flux increased between 9 and 76% at four sites on the Mississippi River and a tributary site on the Missouri River, but changed very little at tributary sites on the Ohio, Iowa, and Illinois Rivers. Increases in flow-normalized concentration and flux at the Mississippi River at Clinton and Missouri River at Hermann were more than three times larger than at any other site. The increases at these two sites contributed much of the 9% increase in flow-normalized nitrate flux leaving the Mississippi River basin. At most sites, concentrations increased more at low and moderate streamflows than at high streamflows, suggesting that increasing groundwater concentrations are having an effect on river concentrations.

@article{doi101021es201221s,
    author = "Sprague, Lori A. and Hirsch, Robert M. and Aulenbach, Brent T.",
    title = "Nitrate in the Mississippi River and Its Tributaries, 1980 to 2008: Are We Making Progress?",
    year = "2011",
    journal = "Environmental Science \& Technology",
    abstract = "Changes in nitrate concentration and flux between 1980 and 2008 at eight sites in the Mississippi River basin were determined using a new statistical method that accommodates evolving nitrate behavior over time and produces flow-normalized estimates of nitrate concentration and flux that are independent of random variations in streamflow. The results show that little consistent progress has been made in reducing riverine nitrate since 1980, and that flow-normalized concentration and flux are increasing in some areas. Flow-normalized nitrate concentration and flux increased between 9 and 76\% at four sites on the Mississippi River and a tributary site on the Missouri River, but changed very little at tributary sites on the Ohio, Iowa, and Illinois Rivers. Increases in flow-normalized concentration and flux at the Mississippi River at Clinton and Missouri River at Hermann were more than three times larger than at any other site. The increases at these two sites contributed much of the 9\% increase in flow-normalized nitrate flux leaving the Mississippi River basin. At most sites, concentrations increased more at low and moderate streamflows than at high streamflows, suggesting that increasing groundwater concentrations are having an effect on river concentrations.",
    url = "https://doi.org/10.1021/es201221s",
    doi = "10.1021/es201221s",
    openalex = "W2023112897",
    references = "doi101890080085"
}

Sediment flux from rivers to oceans is the fundamental driver of fluvio‐deltaic morphodynamics and continental margin sedimentation, yet sediment transport across the river‐to‐marine boundary is poorly understood. Coastal rivers typically are affected by backwater, a zone of spatially decelerating flow that is transitional between normal flow upstream and the offshore river plume. Flow deceleration in the backwater zone, as well as spreading of the offshore plume, should render rivers highly depositional near their mouths, leading to sedimentation and eventual elimination of the backwater zone at steady state. This reasoning is counter to observations of riverbed scour, erosional bed forms, and long‐lived backwater zones near the mouths of some coastal rivers (e.g., Mississippi River, United States). To explain these observations, we present a quasi‐2‐D model of a coupled fluvial backwater and offshore river plume system and apply it to the Mississippi River. Results show that during high‐discharge events the normal‐flow depth can become larger than the water depth at the river mouth resulting in drawdown of the water surface, spatial acceleration of flow, and erosion of the riverbed. As proposed by Lane (1957), the transition to drawdown and erosion is ultimately forced by spreading of the offshore river plume. This points to the need to model coupled river and river plume systems with a dynamic backwater zone under a suite of discharges to accurately capture fluvio‐deltaic morphodynamics and connectivity between fluvial sediment sources and marine depositional sinks.

@article{doi1010292011jf002079,
    author = "Lamb, Michael P. and Nittrouer, Jeffrey A. and Mohrig, David and Shaw, John",
    title = "Backwater and river plume controls on scour upstream of river mouths: Implications for fluvio‐deltaic morphodynamics",
    year = "2011",
    journal = "Journal of Geophysical Research Atmospheres",
    abstract = "Sediment flux from rivers to oceans is the fundamental driver of fluvio‐deltaic morphodynamics and continental margin sedimentation, yet sediment transport across the river‐to‐marine boundary is poorly understood. Coastal rivers typically are affected by backwater, a zone of spatially decelerating flow that is transitional between normal flow upstream and the offshore river plume. Flow deceleration in the backwater zone, as well as spreading of the offshore plume, should render rivers highly depositional near their mouths, leading to sedimentation and eventual elimination of the backwater zone at steady state. This reasoning is counter to observations of riverbed scour, erosional bed forms, and long‐lived backwater zones near the mouths of some coastal rivers (e.g., Mississippi River, United States). To explain these observations, we present a quasi‐2‐D model of a coupled fluvial backwater and offshore river plume system and apply it to the Mississippi River. Results show that during high‐discharge events the normal‐flow depth can become larger than the water depth at the river mouth resulting in drawdown of the water surface, spatial acceleration of flow, and erosion of the riverbed. As proposed by Lane (1957), the transition to drawdown and erosion is ultimately forced by spreading of the offshore river plume. This points to the need to model coupled river and river plume systems with a dynamic backwater zone under a suite of discharges to accurately capture fluvio‐deltaic morphodynamics and connectivity between fluvial sediment sources and marine depositional sinks.",
    url = "https://doi.org/10.1029/2011jf002079",
    doi = "10.1029/2011jf002079",
    openalex = "W2038083194",
    references = "doi101016jgeomorph200601045, doi1010292008wr007382, doi1010292011gl050197, doi101111j13653091200800961x, doi101146annurevmarine120709142856"
}

Despite the recognized importance of reservoirs and dams, global datasets describing their characteristics and geographical distribution are largely incomplete. To enable advanced assessments of the role and effects of dams within the global river network and to support strategies for mitigating ecohydrological and socioeconomic costs, we introduce here the spatially explicit and hydrologically linked Global Reservoir and Dam database (GRanD). As of early 2011, GRanD contains information regarding 6862 dams and their associated reservoirs, with a total storage capacity of 6197 km 3. On the basis of these records, we estimate that about 16.7 million reservoirs larger than 0.01 ha – with a combined storage capacity of approximately 8070 km 3 – may exist worldwide, increasing Earth's terrestrial surface water area by more than 305 000 km 2. We find that 575 900 river kilometers, or 7.6% of the world's rivers with average flows above 1 cubic meter per second (m 3 s −1), are affected by a cumulative upstream reservoir capacity that exceeds 2% of their annual flow; the impact is highest for large rivers with average flows above 1000 m 3 s −1, of which 46.7% are affected. Finally, a sensitivity analysis suggests that smaller reservoirs have substantial impacts on the spatial extent of flow alterations despite their minor role in total reservoir capacity.

@article{doi101890100125,
    author = "Lehner, Bernhard and Liermann, Catherine Reidy and Revenga, Carmen and Vörösmarty, Charles J and Fekete, B M and Crouzet, Philippe and Döll, Petra and Endejan, Marcel and Frenken, Karen and Magome, Jun and Nilsson, Christer and Robertson, James and Rödel, Raimund and Sindorf, Nikolai and Wisser, Dominik",
    title = "High‐resolution mapping of the world's reservoirs and dams for sustainable river‐flow management",
    year = "2011",
    journal = "Frontiers in Ecology and the Environment",
    abstract = "Despite the recognized importance of reservoirs and dams, global datasets describing their characteristics and geographical distribution are largely incomplete. To enable advanced assessments of the role and effects of dams within the global river network and to support strategies for mitigating ecohydrological and socioeconomic costs, we introduce here the spatially explicit and hydrologically linked Global Reservoir and Dam database (GRanD). As of early 2011, GRanD contains information regarding 6862 dams and their associated reservoirs, with a total storage capacity of 6197 km 3. On the basis of these records, we estimate that about 16.7 million reservoirs larger than 0.01 ha – with a combined storage capacity of approximately 8070 km 3 – may exist worldwide, increasing Earth's terrestrial surface water area by more than 305 000 km 2. We find that 575 900 river kilometers, or 7.6\% of the world's rivers with average flows above 1 cubic meter per second (m 3 s −1), are affected by a cumulative upstream reservoir capacity that exceeds 2\% of their annual flow; the impact is highest for large rivers with average flows above 1000 m 3 s −1, of which 46.7\% are affected. Finally, a sensitivity analysis suggests that smaller reservoirs have substantial impacts on the spatial extent of flow alterations despite their minor role in total reservoir capacity.",
    url = "https://doi.org/10.1890/100125",
    doi = "10.1890/100125",
    openalex = "W2103751670",
    references = "doi101017s1464793105006950"
}

Abstract. Silicon (Si) released as H4SiO4 by weathering of Si-containing solid phases is partly recycled through vegetation before its land-to-rivers transfer. By accumulating in terrestrial plants to a similar extent as some major macronutrients (0.1–10% Si dry weight), Si becomes largely mobile in the soil-plant system. Litter-fall leads to a substantial reactive biogenic silica pool in soil, which contributes to the release of dissolved Si (DSi) in soil solution. Understanding the biogeochemical cycle of silicon in surface environments and the DSi export from soils into rivers is crucial given that the marine primary bio-productivity depends on the availability of H4SiO4 for phytoplankton that requires Si. Continental fluxes of DSi seem to be deeply influenced by climate (temperature and runoff) as well as soil-vegetation systems. Therefore, continental areas can be characterized by various abilities to transfer DSi from soil-plant systems towards rivers. Here we pay special attention to those processes taking place in soil-plant systems and controlling the Si transfer towards rivers. We aim at identifying relevant geochemical tracers of Si pathways within the soil-plant system to obtain a better understanding of the origin of DSi exported towards rivers. In this review, we compare different soil-plant systems (weathering-unlimited and weathering-limited environments) and the variations of the geochemical tracers (Ge/Si ratios and δ30Si) in DSi outputs. We recommend the use of biogeochemical tracers in combination with Si mass-balances and detailed physico-chemical characterization of soil-plant systems to allow better insight in the sources and fate of Si in these biogeochemical systems.

@article{doi105194bg8892011,
    author = "Cornelis, Jean‐Thomas and Delvaux, Bruno and Georg, R. Bastian and Lucas, Yves and Ranger, Jacques and Opfergelt, Sophie",
    title = "Tracing the origin of dissolved silicon transferred from various soil-plant systems towards rivers: a review",
    year = "2011",
    journal = "Biogeosciences",
    abstract = "Abstract. Silicon (Si) released as H4SiO4 by weathering of Si-containing solid phases is partly recycled through vegetation before its land-to-rivers transfer. By accumulating in terrestrial plants to a similar extent as some major macronutrients (0.1–10\% Si dry weight), Si becomes largely mobile in the soil-plant system. Litter-fall leads to a substantial reactive biogenic silica pool in soil, which contributes to the release of dissolved Si (DSi) in soil solution. Understanding the biogeochemical cycle of silicon in surface environments and the DSi export from soils into rivers is crucial given that the marine primary bio-productivity depends on the availability of H4SiO4 for phytoplankton that requires Si. Continental fluxes of DSi seem to be deeply influenced by climate (temperature and runoff) as well as soil-vegetation systems. Therefore, continental areas can be characterized by various abilities to transfer DSi from soil-plant systems towards rivers. Here we pay special attention to those processes taking place in soil-plant systems and controlling the Si transfer towards rivers. We aim at identifying relevant geochemical tracers of Si pathways within the soil-plant system to obtain a better understanding of the origin of DSi exported towards rivers. In this review, we compare different soil-plant systems (weathering-unlimited and weathering-limited environments) and the variations of the geochemical tracers (Ge/Si ratios and δ30Si) in DSi outputs. We recommend the use of biogeochemical tracers in combination with Si mass-balances and detailed physico-chemical characterization of soil-plant systems to allow better insight in the sources and fate of Si in these biogeochemical systems.",
    url = "https://doi.org/10.5194/bg-8-89-2011",
    doi = "10.5194/bg-8-89-2011",
    openalex = "W2122702323",
    references = "doi1010292008gb003281"
}

@article{doi101016jrse201211023,
    author = "Olmanson, Leif G. and Brezonik, Patrick L. and Bauer, Marvin E.",
    title = "Airborne hyperspectral remote sensing to assess spatial distribution of water quality characteristics in large rivers: The Mississippi River and its tributaries in Minnesota",
    year = "2012",
    journal = "Remote Sensing of Environment",
    url = "https://doi.org/10.1016/j.rse.2012.11.023",
    doi = "10.1016/j.rse.2012.11.023",
    openalex = "W2125240520",
    references = "doi102134jeq2001302329x"
}

The Mississippi delta region of south Louisiana houses a wealth of resources within a dynamic, subsiding landscape. Foundations for the delta region reflect Neogene evolution of the depocenter, whereas details of the modern landscape reflect late Pleistocene to Holocene evolution of the alluvial-deltaic plain. The Holocene delta plain was constructed by cyclical growth of deltaic headlands, followed by avulsion and relocation of the fluvial sediment source. Abandoned headlands were then submerged and reworked while a new headland was created at the site of active fluvial sediment input. Historic-period levees have decoupled the delta plain from its fluvial sediment source at the same time global sea-level rise was accelerating, which has accelerated delta-plain submergence. Diversions of Mississippi River water and sediment are necessary to achieve delta plain sustainability, but upstream dams trap ∼50% of the total sediment load, and there is not enough supply to keep pace with subsidence and accelerated sea-level rise. The future delta region will not resemble the recent past, and significant drowning is inevitable.

@article{doi101146annurevearth042711105248,
    author = "Blum, Michael D. and Roberts, Harry H.",
    title = "The Mississippi Delta Region: Past, Present, and Future",
    year = "2012",
    journal = "Annual Review of Earth and Planetary Sciences",
    abstract = "The Mississippi delta region of south Louisiana houses a wealth of resources within a dynamic, subsiding landscape. Foundations for the delta region reflect Neogene evolution of the depocenter, whereas details of the modern landscape reflect late Pleistocene to Holocene evolution of the alluvial-deltaic plain. The Holocene delta plain was constructed by cyclical growth of deltaic headlands, followed by avulsion and relocation of the fluvial sediment source. Abandoned headlands were then submerged and reworked while a new headland was created at the site of active fluvial sediment input. Historic-period levees have decoupled the delta plain from its fluvial sediment source at the same time global sea-level rise was accelerating, which has accelerated delta-plain submergence. Diversions of Mississippi River water and sediment are necessary to achieve delta plain sustainability, but upstream dams trap ∼50\% of the total sediment load, and there is not enough supply to keep pace with subsidence and accelerated sea-level rise. The future delta region will not resemble the recent past, and significant drowning is inevitable.",
    url = "https://doi.org/10.1146/annurev-earth-042711-105248",
    doi = "10.1146/annurev-earth-042711-105248",
    openalex = "W2096613926",
    references = "crossref1995cenozoic, doi101007s1071201191191, doi1010160025322789901278, doi101016jjhydrol201004001, doi101016s0277379101001019, doi101016s0967065397885973, doi1010292005gl024826, doi1010292006eo450001, doi1010292009eo420001, doi101038ngeo553, doi101038ngeo629, doi101073pnas0907765106, doi101126science1135456, doi101130ges006471, doi101146annurevearth32082503144359, doi101146annurevmarine120709142856, doi1013068626c37f173b11d78645000102c1865d, doi102110jsr2009070, doi103133ofr20051216, doi104835025539, openalexw1520428197, openalexw1846023905, openalexw2106140657, openalexw2255943944"
}

@article{doi101038ngeo2142,
    author = "Nittrouer, Jeffrey A. and Viparelli, E.",
    title = "Sand as a stable and sustainable resource for nourishing the Mississippi River delta",
    year = "2014",
    journal = "Nature Geoscience",
    url = "https://doi.org/10.1038/ngeo2142",
    doi = "10.1038/ngeo2142",
    openalex = "W2003849608",
    references = "doi101002hyp7477, doi1010292008je003077, doi1010292009eo420001, doi1010292011gl049458, doi101038ngeo553, doi101038ngeo629, doi10108004353676198711880207, doi101126science22446531093, doi101130b304971, doi101146annurevmarine120709142856, doi102307211375, openalexw2255943944"
}

Abstract The morphology of an alluvial river channel affects the movement of water and sediment along it, but in the longer run is shaped by those processes. This interplay has mostly been investigated empirically within the paradigm of Newtonian mechanics. In rivers, this has created an emphasis on equilibrium configurations with simple morphology and uniform steady flow. But transient adjustment, whether between equilibrium states or indefinitely, is to be expected in a world in which hydrology, sediment supply, and base level are not fixed. More fundamentally, water flows and all the phenomena that accompany them are inherently unsteady, and flows in natural channels are characteristically nonuniform. The morphodynamics of alluvial river channels is the striking consequence. In this paper, we develop the essential connection between the episodic nature of bed material transport and the production of river morphology, emphasizing the fundamental problems of sediment transport, the role of bar evolution in determining channel form, the role of riparian vegetation, and the wide range of time scales for change. As the key integrative exercise, we emphasize the importance of physics‐based modeling of morphodynamics. We note consequences that can be of benefit to society if properly understood. These include the possibility to better be able to model how varying flows drive morphodynamic change, to understand the influence of the sediments themselves on morphodynamics, and to recognize the inherent necessity for rivers that transport bed material to deform laterally. We acknowledge pioneering contributions in WRR and elsewhere that have introduced some of these themes.

@article{doi1010022014wr016862,
    author = "Church, Michael and Ferguson, Rob",
    title = "Morphodynamics: Rivers beyond steady state",
    year = "2015",
    journal = "Water Resources Research",
    abstract = "Abstract The morphology of an alluvial river channel affects the movement of water and sediment along it, but in the longer run is shaped by those processes. This interplay has mostly been investigated empirically within the paradigm of Newtonian mechanics. In rivers, this has created an emphasis on equilibrium configurations with simple morphology and uniform steady flow. But transient adjustment, whether between equilibrium states or indefinitely, is to be expected in a world in which hydrology, sediment supply, and base level are not fixed. More fundamentally, water flows and all the phenomena that accompany them are inherently unsteady, and flows in natural channels are characteristically nonuniform. The morphodynamics of alluvial river channels is the striking consequence. In this paper, we develop the essential connection between the episodic nature of bed material transport and the production of river morphology, emphasizing the fundamental problems of sediment transport, the role of bar evolution in determining channel form, the role of riparian vegetation, and the wide range of time scales for change. As the key integrative exercise, we emphasize the importance of physics‐based modeling of morphodynamics. We note consequences that can be of benefit to society if properly understood. These include the possibility to better be able to model how varying flows drive morphodynamic change, to understand the influence of the sediments themselves on morphodynamics, and to recognize the inherent necessity for rivers that transport bed material to deform laterally. We acknowledge pioneering contributions in WRR and elsewhere that have introduced some of these themes.",
    url = "https://doi.org/10.1002/2014wr016862",
    doi = "10.1002/2014wr016862",
    openalex = "W1656617355",
    references = "doi101146annurevearth32101802120201"
}

Provides reviews of all major facets of hydrology. Topics covered include: influences of the atmosphere and of land and vegetation on stream flow; temporal and spatial variability of stream flow, with separate chapters on floods and on low flow and hydrologic drought; snow and ice, the frozen components of the hydrosphere; the hydrology of lakes and wetlands; hydrogeochemistry of rivers and lakes; the aquatic biota; sediment movement and storage; the riverscape for selected North American rivers; and the influence of Man on hydrologic systems. Accompanying color plates show histograms of river water chemistry, runoff and flow regimes, and the distribution of precipitation minus evaporation for North America.

@incollection{doi101130dnaggnao1255,
    author = "Meade, Robert H. and Yuzyk, Ted R. and Day, T J",
    title = "Movement and storage of sediment in rivers of the United States and Canada",
    year = "2015",
    booktitle = "Geological Society of America eBooks",
    abstract = "Provides reviews of all major facets of hydrology. Topics covered include: influences of the atmosphere and of land and vegetation on stream flow; temporal and spatial variability of stream flow, with separate chapters on floods and on low flow and hydrologic drought; snow and ice, the frozen components of the hydrosphere; the hydrology of lakes and wetlands; hydrogeochemistry of rivers and lakes; the aquatic biota; sediment movement and storage; the riverscape for selected North American rivers; and the influence of Man on hydrologic systems. Accompanying color plates show histograms of river water chemistry, runoff and flow regimes, and the distribution of precipitation minus evaporation for North America.",
    url = "https://doi.org/10.1130/dnag-gna-o1.255",
    doi = "10.1130/dnag-gna-o1.255",
    openalex = "W2477735327",
    references = "openalexw1592594904"
}

Abstract Tidal rivers are a vital and little studied nexus between physical oceanography and hydrology. It is only in the last few decades that substantial research efforts have been focused on the interactions of river discharge with tidal waves and storm surges into regions beyond the limit of salinity intrusion, a realm that can extend inland hundreds of kilometers. One key phenomenon resulting from this interaction is the emergence of large fortnightly tides, which are forced long waves with amplitudes that may increase beyond the point where astronomical tides have become extinct. These can be larger than the linear tide itself at more landward locations, and they greatly influence tidal river water levels and wetland inundation. Exploration of the spectral redistribution and attenuation of tidal energy in rivers has led to new appreciation of a wide range of consequences for fluvial and coastal sedimentology, delta evolution, wetland conservation, and salinity intrusion under the influence of sea level rise and delta subsidence. Modern research aims at unifying traditional harmonic tidal analysis, nonparametric regression techniques, and the existing understanding of tidal hydrodynamics to better predict and model tidal river dynamics both in single‐thread channels and in branching channel networks. In this context, this review summarizes results from field observations and modeling studies set in tidal river environments as diverse as the Amazon in Brazil, the Columbia, Fraser and Saint Lawrence in North America, the Yangtze and Pearl in China, and the Berau and Mahakam in Indonesia. A description of state‐of‐the‐art methods for a comprehensive analysis of water levels, wave propagation, discharges, and inundation extent in tidal rivers is provided. Implications for lowland river deltas are also discussed in terms of sedimentary deposits, channel bifurcation, avulsion, and salinity intrusion, addressing contemporary research challenges.

@article{doi1010022015rg000507,
    author = "Hoitink, A.J.F. and Jay, David A.",
    title = "Tidal river dynamics: Implications for deltas",
    year = "2016",
    journal = "Reviews of Geophysics",
    abstract = "Abstract Tidal rivers are a vital and little studied nexus between physical oceanography and hydrology. It is only in the last few decades that substantial research efforts have been focused on the interactions of river discharge with tidal waves and storm surges into regions beyond the limit of salinity intrusion, a realm that can extend inland hundreds of kilometers. One key phenomenon resulting from this interaction is the emergence of large fortnightly tides, which are forced long waves with amplitudes that may increase beyond the point where astronomical tides have become extinct. These can be larger than the linear tide itself at more landward locations, and they greatly influence tidal river water levels and wetland inundation. Exploration of the spectral redistribution and attenuation of tidal energy in rivers has led to new appreciation of a wide range of consequences for fluvial and coastal sedimentology, delta evolution, wetland conservation, and salinity intrusion under the influence of sea level rise and delta subsidence. Modern research aims at unifying traditional harmonic tidal analysis, nonparametric regression techniques, and the existing understanding of tidal hydrodynamics to better predict and model tidal river dynamics both in single‐thread channels and in branching channel networks. In this context, this review summarizes results from field observations and modeling studies set in tidal river environments as diverse as the Amazon in Brazil, the Columbia, Fraser and Saint Lawrence in North America, the Yangtze and Pearl in China, and the Berau and Mahakam in Indonesia. A description of state‐of‐the‐art methods for a comprehensive analysis of water levels, wave propagation, discharges, and inundation extent in tidal rivers is provided. Implications for lowland river deltas are also discussed in terms of sedimentary deposits, channel bifurcation, avulsion, and salinity intrusion, addressing contemporary research challenges.",
    url = "https://doi.org/10.1002/2015rg000507",
    doi = "10.1002/2015rg000507",
    openalex = "W2288842236",
    references = "doi1010022014rg000451, doi1010292011gl050197, doi101038ngeo730, doi101111j136530911993tb01347x, doi101146annurevearth32101802120201"
}

@article{doi101016jearscirev201511001,
    author = "Bentley, S. and Blum, M. and Maloney, J. and Pond, L. and Paulsell, R.",
    title = "The Mississippi River source-to-sink system: Perspectives on tectonic, climatic, and anthropogenic influences, Miocene to Anthropocene",
    year = "2016",
    journal = "Earth-Science Reviews",
    url = "https://www.sciencedirect.com/science/article/am/pii/S0012825215300623",
    doi = "10.1016/J.EARSCIREV.2015.11.001",
    is_oa = "true",
    pages = "139-174",
    semanticscholar_citation_count = "187",
    semanticscholar_id = "7b0b1a91358a562f905850981bc439bf6ecf395a",
    volume = "153",
    references = "doi101016jearscirev201510014, doi101130ges009171, doi101146annurevearth042711105248, doi101146annurevmarine120709142856"
}

When river and coastal floods coincide, their impacts are often worse than when they occur in isolation; such floods are examples of 'compound events'. To better understand the impacts of these compound events, we require an improved understanding of the dependence between coastal and river flooding on a global scale. Therefore, in this letter, we: provide the first assessment and mapping of the dependence between observed high sea-levels and high river discharge for deltas and estuaries around the globe; and demonstrate how this dependence may influence the joint probability of floods exceeding both the design discharge and design sea-level. The research was carried out by analysing the statistical dependence between observed sea-levels (and skew surge) from the GESLA-2 dataset, and river discharge using gauged data from the Global Runoff Data Centre, for 187 combinations of stations across the globe. Dependence was assessed using Kendall's rank correlation coefficient () and copula models. We find significant dependence for skew surge conditional on annual maximum discharge at 22% of the stations studied, and for discharge conditional on annual maximum skew surge at 36% of the stations studied. Allowing a time-lag between the two variables up to 5 days, we find significant dependence for skew surge conditional on annual maximum discharge at 56% of stations, and for discharge conditional on annual maximum skew surge at 54% of stations. Using copula models, we show that the joint exceedance probability of events in which both the design discharge and design sea-level are exceeded can be several magnitudes higher when the dependence is considered, compared to when independence is assumed. We discuss several implications, showing that flood risk assessments in these regions should correctly account for these joint exceedance probabilities.

@article{doi10108817489326aad400,
    author = "Ward, Philip J. and Couasnon, Anaïs and Eilander, Dirk and Haigh, Ivan D. and Hendry, Alistair and Muis, Sanne and Veldkamp, Ted and Winsemius, Hessel and Wahl, Thomas",
    title = "Dependence between high sea-level and high river discharge increases flood hazard in global deltas and estuaries",
    year = "2018",
    journal = "Environmental Research Letters",
    abstract = "When river and coastal floods coincide, their impacts are often worse than when they occur in isolation; such floods are examples of 'compound events'. To better understand the impacts of these compound events, we require an improved understanding of the dependence between coastal and river flooding on a global scale. Therefore, in this letter, we: provide the first assessment and mapping of the dependence between observed high sea-levels and high river discharge for deltas and estuaries around the globe; and demonstrate how this dependence may influence the joint probability of floods exceeding both the design discharge and design sea-level. The research was carried out by analysing the statistical dependence between observed sea-levels (and skew surge) from the GESLA-2 dataset, and river discharge using gauged data from the Global Runoff Data Centre, for 187 combinations of stations across the globe. Dependence was assessed using Kendall's rank correlation coefficient () and copula models. We find significant dependence for skew surge conditional on annual maximum discharge at 22\% of the stations studied, and for discharge conditional on annual maximum skew surge at 36\% of the stations studied. Allowing a time-lag between the two variables up to 5 days, we find significant dependence for skew surge conditional on annual maximum discharge at 56\% of stations, and for discharge conditional on annual maximum skew surge at 54\% of stations. Using copula models, we show that the joint exceedance probability of events in which both the design discharge and design sea-level are exceeded can be several magnitudes higher when the dependence is considered, compared to when independence is assumed. We discuss several implications, showing that flood risk assessments in these regions should correctly account for these joint exceedance probabilities.",
    url = "https://doi.org/10.1088/1748-9326/aad400",
    doi = "10.1088/1748-9326/aad400",
    openalex = "W2884018313",
    references = "doi101126scienceaab3574"
}

@article{doi101016jecss201903002,
    author = "Elsey‐Quirk, Tracy and Graham, Sean A. and Mendelssohn, Irving A. and Snedden, Gregg A. and Day, John W. and Twilley, Robert R. and Shaffer, Gary P. and Sharp, Leigh Anne and Pahl, James W. and Lane, Robert R.",
    title = "Mississippi river sediment diversions and coastal wetland sustainability: Synthesis of responses to freshwater, sediment, and nutrient inputs",
    year = "2019",
    journal = "Estuarine Coastal and Shelf Science",
    url = "https://doi.org/10.1016/j.ecss.2019.03.002",
    doi = "10.1016/j.ecss.2019.03.002",
    openalex = "W2921008337",
    references = "doi101007s1162501603744, doi101146annurevearth042711105248, openalexw2255943944"
}

During flooding in 2011, 2013, and 2016 on the Middle Mississippi River between St. Louis and Cape Girardeau, MO, high-energy sand boils developed at the land side levee toe. These recent floods varied from moderate to major events but were well below the design flow line for the levees. This report documents a case study of internal erosion at a levee site in southern Illinois near the town of Ware, which is located in the Preston Drainage and Levee District. Site specific geotechnical data from the Ware site were used to identify parameters, such as top stratum thickness, Unified Soil Classification System (USCS) soil types, engineering properties, geologic depositional environments, stratigraphy, and hydraulic gradients, that influence seepage and poor levee performance. An underlying assumption for this study was that sand boils discovered at the Ware site after the flooding in 2013 were formed during a single flood event. However, sand boils are typically associated with chronic seepage related to underlying site geology, levee orientation with the geology, and blocked exit conditions. Thus, seepage problems tend to progress over time in terms of their severity and response to medium to large flood events.

@misc{doi10210791168133619,
    author = "Kelley, Julie R. and Parkman, Kevin and Strange, Ryan and Breland, Benjamin and Dunbar, Joseph B. and Corcoran, Maureen K.",
    title = "Investigation of sand boils near Ware, IL, Middle Mississippi River, Preston Levee District",
    year = "2019",
    abstract = "During flooding in 2011, 2013, and 2016 on the Middle Mississippi River between St. Louis and Cape Girardeau, MO, high-energy sand boils developed at the land side levee toe. These recent floods varied from moderate to major events but were well below the design flow line for the levees. This report documents a case study of internal erosion at a levee site in southern Illinois near the town of Ware, which is located in the Preston Drainage and Levee District. Site specific geotechnical data from the Ware site were used to identify parameters, such as top stratum thickness, Unified Soil Classification System (USCS) soil types, engineering properties, geologic depositional environments, stratigraphy, and hydraulic gradients, that influence seepage and poor levee performance. An underlying assumption for this study was that sand boils discovered at the Ware site after the flooding in 2013 were formed during a single flood event. However, sand boils are typically associated with chronic seepage related to underlying site geology, levee orientation with the geology, and blocked exit conditions. Thus, seepage problems tend to progress over time in terms of their severity and response to medium to large flood events.",
    url = "https://doi.org/10.21079/11681/33619",
    doi = "10.21079/11681/33619",
    openalex = "W2966078777",
    references = "openalexw2924487243"
}

Climate change is intensifying tropical cyclones, accelerating sea-level rise, and increasing coastal flooding. River deltas are especially vulnerable to flooding because of their low elevations and densely populated cities. Yet, we do not know how many people live on deltas and their exposure to flooding. Using a new global dataset, we show that 339 million people lived on river deltas in 2017 and 89% of those people live in the same latitudinal zone as most tropical cyclone activity. We calculate that 41% (31 million) of the global population exposed to tropical cyclone flooding live on deltas, with 92% (28 million) in developing or least developed economies. Furthermore, 80% (25 million) live on sediment-starved deltas, which cannot naturally mitigate flooding through sediment deposition. Given that coastal flooding will only worsen, we must reframe this problem as one that will disproportionately impact people on river deltas, particularly in developing and least-developed economies.

@article{doi101038s41467020185314,
    author = "Edmonds, Douglas A. and Caldwell, Rebecca L. and Brondízio, Eduardo S. and Siani, Sacha M. O.",
    title = "Coastal flooding will disproportionately impact people on river deltas",
    year = "2020",
    journal = "Nature Communications",
    abstract = "Climate change is intensifying tropical cyclones, accelerating sea-level rise, and increasing coastal flooding. River deltas are especially vulnerable to flooding because of their low elevations and densely populated cities. Yet, we do not know how many people live on deltas and their exposure to flooding. Using a new global dataset, we show that 339 million people lived on river deltas in 2017 and 89\% of those people live in the same latitudinal zone as most tropical cyclone activity. We calculate that 41\% (31 million) of the global population exposed to tropical cyclone flooding live on deltas, with 92\% (28 million) in developing or least developed economies. Furthermore, 80\% (25 million) live on sediment-starved deltas, which cannot naturally mitigate flooding through sediment deposition. Given that coastal flooding will only worsen, we must reframe this problem as one that will disproportionately impact people on river deltas, particularly in developing and least-developed economies.",
    url = "https://doi.org/10.1038/s41467-020-18531-4",
    doi = "10.1038/s41467-020-18531-4",
    openalex = "W3091049267",
    references = "doi101007s1162501603744, doi101016jjhydrol201004001, doi101126scienceaab3574, doi101146annurevmarine120709142856"
}