Legacy sediment

Last updated

Legacy sediment (LS) is depositional bodies of sediment inherited from the increase of human activities since the Neolithic. [1] [2] These include a broad range of land use and land cover changes, such as agricultural clearance, [3] [4] [5] [6] [7] lumbering and clearance of native vegetation, [8] [9] [10] mining, [11] [12] [13] road building, [14] [15] [16] [17] urbanization, [18] [19] [20] as well as alterations brought to river systems in the form of dams and other engineering structures meant to control and regulate natural fluvial processes (erosion, deposition, lateral migration, meandering). [21] [22] [23] The concept of LS is used in geomorphology, ecology, as well as in water quality and toxicological studies.

Contents

LS is distributed in spatially heterogeneous ways throughout a landscape and accumulates to form various landforms. It can progress through the fluvial system through facies changes from hillslope colluvium, to floodplain and wetland alluvium, to fine-grained lacustrine and estuarine slackwater deposits. [1] The temporal nature of LS is time-transgressive, meaning that initiation and peak rates of deposition can take place at different times within a fluvial system, as well as at different times between regions. The intermittent transport of LS can be thought of as a cascading system that reworks LS deposits from hillslopes, into channels and onto floodplains, such that anthropogenic sediment will be mixed with and non-anthropogenic sediment. [24]

River systems record past and present imprints of anthropogenically-forced changes to the environment. LS is an element of change in this context, as it drives fluxes of energy and matter (connectivity) through fluvial systems and provides indication of past land-uses and river dynamics that can inform future trajectories of river response. In this sense, acknowledging the concept of LS can benefit informed policy development in stream restoration, [1] water quality [25] and sediment budget [26] management, protection of aquatic ecosystems, [27] and flood risk. Moreover, the implications of legacy effects associated with anthropogenically modified sediment dynamics are critical in the context of ecosystem services. [28]

Definitions

Post-settlement alluvium

Definitions predominantly indicate post-settlement alluvium North America created as a result of agricultural clearance.

“Legacy Sediment (n.) Are sediments that (1) were eroded from upland slopes during several centuries of intensive land clearing, agriculture, and milling (in the eastern U.S., this occurred from the late 17th to late 19th Centuries); (2) collected along stream corridors and valley bottoms, burying pre-settlement streams, floodplains, wetlands, and dry valleys; and that altered the hydrologic, biologic, aquatic, riparian, and chemical functions of pre-settlement streams and floodplains; (3) accumulated behind ubiquitous low-head mill dams in slackwater environments, resulting in thick accumulations of fine-grained sediment, which distinguishes ‘‘legacy sediment’’ from fluvial deposits associated with meandering streams; (4) can also accumulate as coarser grained, more poorly sorted colluvial (not associated with stream transport) deposits, usually at valley margins; (5) can contain varying amounts of total phosphorus and nitrogen, which contribute to nutrient loads in downstream waterways from bank erosion processes. . .’’ [29]

Anthropogenically-caused episodic sedimentary deposits

As a result of criticism related to the limited scope and applicability of this definition, a more flexible and generic definition has been proposed that (1) includes a broader range of human activities, (2) considers more sediment types apart from post-settlement alluvium, and (3) respects the spatial (nonuniform) and temporal (time-transgressive) variability of LS:

"Legacy sediment: Earth materials—primarily alluvium [or colluvium]—deposited following human disturbances such as deforestation, agricultural land use, or mining. The phrase is often used to describe post-European floodplain sediments, also known as post settlement alluvium. Awareness of legacy sediment has grown in response to the importance it plays in sediment budgets, water quality, river restoration, toxicity, lateral channel connectivity, and geomorphic theory. . .’’ [30]

"Legacy sediment is primarily alluvium [and colluvium] that was deposited following human disturbances in a watershed. The disturbance may have been in the form of deforestation, plowing agricultural land, mining, or other land-use changes. In North America and Australia, legacy sediments are ubiquitous and represent episodic erosion in response to the colonization of land by European settlers who introduced Old World land- clearance technologies (e.g. steel tools and plows pulled by draft animals) and export economies. In these settings, legacy sediments are often described as post-settlement alluvium (PSA), which may cover entire floodplains and bury the pre- settlement soil with a thick mantle of relatively young stratified sediment. [31] [32] [33] [5] " [34]

Types

LS encompasses sediment of differing structures and textures. They can be colluvial, containing poorly sorted, angular rock fragments deposited by mass wasting or sheet erosional processes, [35] alluvial, containing well sorted, rounded clasts and very-fine grained suspended sediment deposited by fluvial processes. [36]

Associated landforms

Most LS is generated on highlands by erosional processes related to mass-wasting, sheet flow, rills and gullies. The deposited colluvium has a low travel distance and accumulates in midslope drapes near the site of erosion, in aprons or sediment wedges at the base of the slope or in fans at the mouth of gullies, debris flows and tributaries. [1]

Floodplains store alluvium through lateral and vertical accretion, i.e. bedload deposits are being incorporated into the floodplain. Depositional episodes reflect the balance between the amount of sediments available and the capacity for it to be transported. Accordingly, the nature of LS on floodplains can be of different nature: [1] (1) graded, when an excess of sediment and a deficit in transport capacity buries floodplains in continuous deposits, (2) cascading, when abundant sediment and limited transport capacity results in a series of frequent, but separated pockets, (3) punctuated, when limited sediment supply but efficient transport leads to deposition only in locally isolated pockets.

In low energy environments like lakes, wetlands, estuaries, LS are dominated by very fine-grained material, such as silts and clays, and form beaches and beach-dune complexes. [1]

Source to sink relationships

Another way to conceptualize the spatial pattern of LS throughout a watershed is through the notion of source and storage or sink zones. [37] Stores differentiate themselves from sinks through their temporal persistence in the landscape, the first being temporary, while the second are more long-lasting. [38] Highlands are characterized by local storage points near the sediment production zone, with larger storage spaces downstream in wider valleys with low gradients. Stores in this parts of a watershed have generally low residence times, as they are episodically reworked by the fluvial system. Sources are linked to sinks through transport or transfer zones, generally characterized by either high transport capacity or little accommodation space for sediment to accumulate in, e.g. steep narrow valleys that are highly effective in transferring sediment downstream. Sinks are most common in low-lying, low gradient areas where flow energy is dissipated across large surfaces, so that accumulation is dominant. Here, storage space and residence time of the deposits increases considerably relative to upstream parts of a watershed.

Legacy effects

Scientific studies documenting the widespread alteration of sediment dynamics (i.e. sediment supply, sediment entrainment, transport, erosion, deposition and storage) by humans lead to the evidence that human activities have come to dominate erosional, depositional and geochemical processes in ecosystems. [39] [28] This is especially pronounced in river systems, given that rivers are the lowest topographic points of any landscape and consequently collect water, solutes, mineral sediment and particular organic matter from the landscape, but also precipitation, solutes and particulates from the atmosphere. Furthermore, increased sediment supply to rivers but reduced sediment transport within a fluvial network resulted in the creation of legacy effects along almost all rivers across the world. For example, even though accelerated anthropogenic soil erosion has increased sediment transport of rivers across the globe by 2.3 (± 0.6) billion metric tons per year, sediment delivery to the world's coasts and oceans has been reduced by 1.4 (± 0.3) billion metric tons per year because of retention within reservoirs. [23] More than 50% of the major watersheds over the world are impacted by dams. [23] [22] In the United States alone, it is estimated that only 2% of river kilometers are not affected by dams. [40] [41]

Human activities lead to legacy effects on river sediments, which manifest themselves as changes to the location, amount and composition of sediments. Legacy effects are temporally and spatially variable and the resulting sediment have varying spatial extents, accumulation rates and residence times within a river system. For example, removal of beaver dams may initially cause local sedimentation within a portion of basin that comprises solely a few hectares. [42] Similarly, one milldam constructed within a river enhances deposition of sediment over several hectares. [7] Conversely, construction of hundreds of kilometers of bank revetment structures, such as levees, has a much more extensive impact across a basin of nearly eliminating overbank sedimentation. [43] Likewise, removal of native vegetation within an upland region of a basin may lead to significant aggradation of valley bottoms along almost the entire course of a river network. [44] Wastewater treatment can remove contaminated sediment within less than a year, [45] but heavy metals and synthetic chemicals may remain within river sediments at toxic standards for decades to centuries. [46]

Three main effects of anthropogenic manipulation of ecosystems are to enhance sedimentation, to reduce or eliminate sedimentation and/or to contaminate sediments with various pollutants. [28]

Enhanced sedimentation

Sedimentation is enhanced by activities that either increase sediment supply to the river from upstream (e.g. agricultural clearing, mining, grazing) or other parts of the watershed or decrease the transport capacity of the river (e.g. flow regulation). [28]

The effects thereof may induce river metamorphosis, i.e. a whole-shift alteration of river morphology. [47] For example, changing crops from grains to potatoes in late 19th century Poland resulted in such increased sediment yields, that meandering rivers metamorphosed into braided rivers. [48] Copper mining in the headwaters of the Ok Tedi River in Papua New Guinea generated about 80 thousand tonnes per day of waste tailings and 121 thousand tonnes per day of mined wasted rock, which were discarded in the river and affected the entire course of the river network, as well as the nearshore environment. [49] The river system responded by aggrading over 6 meters in parts of the basin a decade later. [50] In California, the Bear River still continues to rework and move down sediment generated by mining activities more than a century after these stopped. [51]

Indirectly, climate change can also enhance sedimentation through changes in precipitation and discharge patterns, which have been shown to result in increased mass movements, [52] alterations of wildfire regimes [53] and increased glacial melting. [54]

Reduced sedimentation

Sedimentation is reduced or removed altogether when human activities reduce sediment yields from upstream (e.g. dams and reservoirs within upland regions, sediment detention basins) or reduce the river channel's physical complexity (e.g. channelization, drainage) or disconnect river channels from adjacent floodplains and wetlands (e.g. levees, removal of beaver dams and logjams/large woody debris). [28]

Rapid dam construction in the Mekong River system resulted in 38 dams (as of 2014) and an additional 133 proposed for the main stream and its tributary streams – if all of these were to be constructed, the overall sediment trapping capacity would be 96%. [55] Estimates show that about 100 billion metric tons of sediment are presently stored in reservoirs that have been constructed over the past 50 years. [23] Levee construction in the lower Mississippi River reduced overbank flows by 90%. Bank stabilization measures associated with this project reduced bank erosion and meander lateral migration, while dikes induced bed scour during low flows due to increased flow velocity. Overall, this project lead to a decrease of sediment storage on the floodplain from 89,600 to 7,000 square kilometers between 1882–2000. [56] In Australia's Cann River, wood removal from the channel transformed downstream segments of the river network from a sediment sink to a sediment source. [57]

Contaminated sedimentation

Human activities introduce or concentrate naturally occurring (e.g. nitrogen, phosphorus) or synthetic contaminants and pollutants that get absorbed in sediments and may lead, at toxic levels, to chronic or severe disruption of physiologic mechanisms in all organisms. [28] The most common contaminants that can absorb fine sediment are trace metals, nutrients (e.g. nitrogen, phosphorus), polynuclear aromatic hydrocarbons (PAHs), pathogens, polychlorinated biphenyls (PCBs), pesticides, volatile organic compounds (VOCs). [28]

For instance, two tailing dams of gold mines located in Romanian tributaries of the Danube failed, thereby releasing vast amounts of cyanide-contaminated water and sediment for tens of kilometers downstream, which killed riverine organisms and affected human drinking-water supply for weeks. [58] In the Rio San Juan basin of Peru, acid mine drainage was diverted into a natural lake, leading to extremely high concentrations copper, zinc and lead in the lake sediments. [59] Samples taken by the USGS during 1993-2003 showed that median concentrations of nitrogen and phosphorus in agricultural streams are six times greater than background levels and that, across the US, concentrations in streams commonly lie above levels recommended by the US Environmental Protection Agency in order to protect aquatic life. [60]

See also

Further reading

Related Research Articles

<span class="mw-page-title-main">Erosion</span> Natural processes that remove soil and rock

Erosion is the action of surface processes that removes soil, rock, or dissolved material from one location on the Earth's crust and then transports it to another location where it is deposited. Erosion is distinct from weathering which involves no movement. Removal of rock or soil as clastic sediment is referred to as physical or mechanical erosion; this contrasts with chemical erosion, where soil or rock material is removed from an area by dissolution. Eroded sediment or solutes may be transported just a few millimetres, or for thousands of kilometres.

<span class="mw-page-title-main">Sediment</span> Particulate solid matter that is deposited on the surface of land

Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand and silt can be carried in suspension in river water and on reaching the sea bed deposited by sedimentation; if buried, they may eventually become sandstone and siltstone through lithification.

<span class="mw-page-title-main">Geomorphology</span> Scientific study of landforms

Geomorphology is the scientific study of the origin and evolution of topographic and bathymetric features generated by physical, chemical or biological processes operating at or near Earth's surface. Geomorphologists seek to understand why landscapes look the way they do, to understand landform and terrain history and dynamics and to predict changes through a combination of field observations, physical experiments and numerical modeling. Geomorphologists work within disciplines such as physical geography, geology, geodesy, engineering geology, archaeology, climatology, and geotechnical engineering. This broad base of interests contributes to many research styles and interests within the field.

<span class="mw-page-title-main">Braided river</span> Network of river channels separated by small, and often temporary, islands

A braided river consists of a network of river channels separated by small, often temporary, islands called braid bars or, in British English usage, aits or eyots.

<span class="mw-page-title-main">River delta</span> Silt deposition landform at the mouth of a river

A river delta is a landform shaped like a triangle, created by the deposition of sediment that is carried by a river and enters slower-moving or stagnant water. This occurs when a river enters an ocean, sea, estuary, lake, reservoir, or another river that cannot carry away the supplied sediment. It is so named because its triangle shape resembles the Greek letter Delta. The size and shape of a delta are controlled by the balance between watershed processes that supply sediment, and receiving basin processes that redistribute, sequester, and export that sediment. The size, geometry, and location of the receiving basin also plays an important role in delta evolution.

<span class="mw-page-title-main">Alluvial fan</span> Fan-shaped deposit of sediment

An alluvial fan is an accumulation of sediments that fans outwards from a concentrated source of sediments, such as a narrow canyon emerging from an escarpment. They are characteristic of mountainous terrain in arid to semiarid climates, but are also found in more humid environments subject to intense rainfall and in areas of modern glaciation. They range in area from less than 1 square kilometer (0.4 sq mi) to almost 20,000 square kilometers (7,700 sq mi).

<span class="mw-page-title-main">Fluvial processes</span> Processes associated with rivers and streams

In geography and geology, fluvial processes are associated with rivers and streams and the deposits and landforms created by them. When the stream or rivers are associated with glaciers, ice sheets, or ice caps, the term glaciofluvial or fluvioglacial is used.

Denudation is the geological processes in which moving water, ice, wind, and waves erode the Earth's surface, leading to a reduction in elevation and in relief of landforms and landscapes. Although the terms erosion and denudation are used interchangeably, erosion is the transport of soil and rocks from one location to another, and denudation is the sum of processes, including erosion, that result in the lowering of Earth's surface. Endogenous processes such as volcanoes, earthquakes, and tectonic uplift can expose continental crust to the exogenous processes of weathering, erosion, and mass wasting. The effects of denudation have been recorded for millennia but the mechanics behind it have been debated for the past 200 years and have only begun to be understood in the past few decades.

Fluvial terraces are elongated terraces that flank the sides of floodplains and fluvial valleys all over the world. They consist of a relatively level strip of land, called a "tread", separated from either an adjacent floodplain, other fluvial terraces, or uplands by distinctly steeper strips of land called "risers". These terraces lie parallel to and above the river channel and its floodplain. Because of the manner in which they form, fluvial terraces are underlain by fluvial sediments of highly variable thickness. River terraces are the remnants of earlier floodplains that existed at a time when either a stream or river was flowing at a higher elevation before its channel downcut to create a new floodplain at a lower elevation. Changes in elevation can be due to changes in the base level of the fluvial system, which leads to headward erosion along the length of either a stream or river, gradually lowering its elevation. For example, downcutting by a river can lead to increased velocity of a tributary, causing that tributary to erode toward its headwaters. Terraces can also be left behind when the volume of the fluvial flow declines due to changes in climate, typical of areas which were covered by ice during periods of glaciation, and their adjacent drainage basins.

<span class="mw-page-title-main">Terrace (geology)</span> A step-like landform

In geology, a terrace is a step-like landform. A terrace consists of a flat or gently sloping geomorphic surface, called a tread, that is typically bounded on one side by a steeper ascending slope, which is called a "riser" or "scarp". The tread and the steeper descending slope together constitute the terrace. Terraces can also consist of a tread bounded on all sides by a descending riser or scarp. A narrow terrace is often called a bench.

The terms river morphology and its synonym stream morphology are used to describe the shapes of river channels and how they change in shape and direction over time. The morphology of a river channel is a function of a number of processes and environmental conditions, including the composition and erodibility of the bed and banks ; erosion comes from the power and consistency of the current, and can effect the formation of the river's path. Also, vegetation and the rate of plant growth; the availability of sediment; the size and composition of the sediment moving through the channel; the rate of sediment transport through the channel and the rate of deposition on the floodplain, banks, bars, and bed; and regional aggradation or degradation due to subsidence or uplift. River morphology can also be affected by human interaction, which is a way the river responds to a new factor in how the river can change its course. An example of human induced change in river morphology is dam construction, which alters the ebb flow of fluvial water and sediment, therefore creating or shrinking estuarine channels. A river regime is a dynamic equilibrium system, which is a way of classifying rivers into different categories. The four categories of river regimes are Sinuous canali- form rivers, Sinuous point bar rivers, Sinuous braided rivers, and Non-sinuous braided rivers.

<span class="mw-page-title-main">Riffle</span> Shallow landform in a flowing channel

A riffle is a shallow landform in a flowing channel. Colloquially, it is a shallow place in a river where water flows quickly past rocks. However, in geology a riffle has specific characteristics.

<span class="mw-page-title-main">Backswamp</span> Environment on a floodplain where deposits settle after a flood

In geology, a backswamp is a type of depositional environment commonly found in a floodplain. It is where deposits of fine silts and clays settle after a flood. These deposits create a marsh-like landscape that is often poorly drained and usually lower than the rest of the floodplain.

<span class="mw-page-title-main">Log jam</span> Accumulation of large wood in a stream or river, preventing movement downstream

A log jam is a naturally occurring phenomenon characterized by a dense accumulation of tree trunks and pieces of large wood across a vast section of a river, stream, or lake. Log jams in rivers and streams often span the entirety of the water's surface from bank to bank. Log jams form when trees floating in the water become entangled with other trees floating in the water or become snagged on rocks, large woody debris, or other objects anchored underwater. They can build up slowly over months or years, or they can happen instantaneously when large numbers of trees are swept into the water after natural disasters. A notable example caused by a natural disaster is the log jam that occurred in Spirit Lake following a landslide triggered by the eruption of Mount St. Helens. Until they are dismantled by natural causes or humans, log jams can grow quickly, as more wood arriving from upstream becomes entangled in the mass. Log jams can persist for many decades, as is the case with the log jam in Spirit Lake.

<span class="mw-page-title-main">Avulsion (river)</span> Rapid abandonment of a river channel and formation of a new channel

In sedimentary geology and fluvial geomorphology, avulsion is the rapid abandonment of a river channel and the formation of a new river channel. Avulsions occur as a result of channel slopes that are much less steep than the slope that the river could travel if it took a new course.

<span class="mw-page-title-main">Alluvial river</span> Type of river

An alluvial river is one in which the bed and banks are made up of mobile sediment and/or soil. Alluvial rivers are self-formed, meaning that their channels are shaped by the magnitude and frequency of the floods that they experience, and the ability of these floods to erode, deposit, and transport sediment. For this reason, alluvial rivers can assume a number of forms based on the properties of their banks; the flows they experience; the local riparian ecology; and the amount, size, and type of sediment that they carry.

Channel patterns are found in rivers, streams, and other bodies of water that transport water from one place to another. Systems of branching river channels dissect most of the sub-aerial landscape, each in a valley proportioned to its size. Whether formed by chance or necessity, by headward erosion or downslope convergence, whether inherited or newly formed. Depending on different geological factors such as weathering, erosion, depositional environment, and sediment type, different types of channel patterns can form.

<span class="mw-page-title-main">Slip-off slope</span> Depositional landform on the inside convex bank of a meandering river

A slip-off slope is a depositional landform that occurs on the inside convex bank of a meandering river. The term can refer to two different features: one in a freely meandering river with a floodplain and the other in an entrenched river.

An alluvial megafan is a large cone or fan-shaped deposit built up by complex deposition patterns of stream flows originating from a single source point known as an apex. Megafans differ from alluvial fans in their sheer size. Due to their larger size, they may be formed by different geomorphic processes. The criterion of what differentiates megafans from typical alluvial fans is an artificial one of scale. The scale divide varies in the literature, with the most common being a 100-km apex-to-toe length. Alternative values as little of 30-km apex-to-toe length have been proposed, as well as alternative metrics like coverage areas of greater than 10,000 square-km.

<span class="mw-page-title-main">River incision</span>

River incision is the narrow erosion caused by a river or stream that is far from its base level. River incision is common after tectonic uplift of the landscape. Incision by multiple rivers result in a dissected landscape, for example a dissected plateau. River incision is the natural process by which a river cuts downward into its bed, deepening the active channel. Though it is a natural process, it can be accelerated rapidly by human factors including land use changes such as timber harvest, mining, agriculture, and road and dam construction. The rate of incision is a function of basal shear-stress. Shear stress is increased by factors such as sediment in the water, which increase its density. Shear stress is proportional to water mass, gravity, and WSS:

References

  1. 1 2 3 4 5 6 James, L. Allan (2013). "Legacy sediment: Definitions and processes of episodically produced anthropogenic sediment". Anthropocene. 2: 16–26. doi:10.1016/j.ancene.2013.04.001.
  2. ↑ Dotterweich, Markus (2008). "The history of soil erosion and fluvial deposits in small catchments of central Europe: Deciphering the long-term interaction between humans and the environment — A review". Geomorphology. 101 (1–2): 192–208. Bibcode:2008Geomo.101..192D. doi:10.1016/j.geomorph.2008.05.023.
  3. ↑ Sternberg, C. W. (1941-04-01). "Some Principles of Accelerated Stream and Valley Sedimentation. Stafford C. Happ , Gordon Rittenhouse , G. C. Dobson". The Journal of Geology. 49 (3): 334–335. doi:10.1086/624968. ISSN   0022-1376.
  4. ↑ Wayne., Trimble, Stanley (2008). Man-induced soil erosion on the southern Piedmont, 1700-1970. Goudie, Andrew. (Enhanced ed.). Ankeny, Iowa: Soil and Water Conservation Society. ISBN   9780976943259. OCLC   191697291.{{cite book}}: CS1 maint: multiple names: authors list (link)
  5. 1 2 Knox, James C. (2006). "Floodplain sedimentation in the Upper Mississippi Valley: Natural versus human accelerated". Geomorphology. 79 (3–4): 286–310. Bibcode:2006Geomo..79..286K. doi:10.1016/j.geomorph.2006.06.031.
  6. ↑ Jackson, C.R., Martin, J.K., Leigh, D.S., West, L.T. (2005). "A southeastern piedmont watershed sediment budget: Evidence for a multi-millennial agricultural legacy". Journal of Soil and Water Conservation. 60: 298–310.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  7. 1 2 Walter, Robert C.; Merritts, Dorothy J. (2008-01-18). "Natural Streams and the Legacy of Water-Powered Mills". Science. 319 (5861): 299–304. Bibcode:2008Sci...319..299W. doi:10.1126/science.1151716. ISSN   0036-8075. PMID   18202284. S2CID   206509868.
  8. ↑ Megahan, W.F., Bohn, C.C. (1989). "Progressive, long-term slope failure following road construction and logging on noncohesive, granitic soils of the Idaho Batholith". Headwaters Hydrology, American Water Resources Association: 501–510.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  9. ↑ Douglas, Ian; Spencer, Tom; Greer, Tony; Bidin, Kawi; Sinun, Waidi; Meng, Wong Wai (1992-03-30). "The impact of selective commercial logging on stream hydrology, chemistry and sediment loads in the Ulu Segama rain forest, Sabah, Malaysia". Phil. Trans. R. Soc. Lond. B. 335 (1275): 397–406. doi:10.1098/rstb.1992.0031. ISSN   0962-8436.
  10. ↑ Kasprak, Alan; Magilligan, Francis J.; Nislow, Keith H.; Renshaw, Carl E.; Snyder, Noah P.; Dade, W. Brian (2013). "Differentiating the relative importance of land cover change and geomorphic processes on fine sediment sequestration in a logged watershed". Geomorphology. 185: 67–77. Bibcode:2013Geomo.185...67K. doi:10.1016/j.geomorph.2012.12.005.
  11. ↑ Gilbert, G.K (1917). "Hydraulic mining debris in the Sierra Nevada" (PDF). U.S. Geological Survey Professional Paper. Professional Paper. 105. doi:10.3133/pp105.
  12. ↑ James, A. (1994). "Channel changes wrought by gold mining: northern Sierra Nevada, California. Effects of human-induced changes on hydrologic systems". American Water Resources Association: 629–638.
  13. ↑ Palmer, M. A.; Bernhardt, E. S.; Schlesinger, W. H.; Eshleman, K. N.; Foufoula-Georgiou, E.; Hendryx, M. S.; Lemly, A. D.; Likens, G. E.; Loucks, O. L. (2010-01-08). "Mountaintop Mining Consequences". Science. 327 (5962): 148–149. Bibcode:2010Sci...327..148P. doi:10.1126/science.1180543. ISSN   0036-8075. PMID   20056876. S2CID   206522928.
  14. ↑ Froehlich, W. (1991). "Sediment production from unmetalled road surfaces. Sediment and Stream Water Quality in a Changing Environment: Trends and Explanation". IAHS Publication. 203: 21–29.
  15. ↑ Luce, Charles H.; Black, Thomas A. (1999-08-01). "Sediment production from forest roads in western Oregon". Water Resources Research. 35 (8): 2561–2570. Bibcode:1999WRR....35.2561L. CiteSeerX   10.1.1.364.1533 . doi:10.1029/1999wr900135. ISSN   1944-7973. S2CID   15196685.
  16. ↑ Wemple, Beverley C.; Swanson, Frederick J.; Jones, Julia A. (2001-02-01). "Forest roads and geomorphic process interactions, Cascade Range, Oregon". Earth Surface Processes and Landforms. 26 (2): 191–204. Bibcode:2001ESPL...26..191W. doi:10.1002/1096-9837(200102)26:2<191::aid-esp175>3.0.co;2-u. ISSN   1096-9837.
  17. ↑ Erskine, Wayne D. (2013-03-15). "Soil colour as a tracer of sediment dispersion from erosion of forest roads in Chichester State Forest, NSW, Australia". Hydrological Processes. 27 (6): 933–942. Bibcode:2013HyPr...27..933E. doi:10.1002/hyp.9412. ISSN   1099-1085. S2CID   128936558.
  18. ↑ Wolman, M. Gordon (1967). "A Cycle of Sedimentation and Erosion in Urban River Channels". Geografiska Annaler: Series A, Physical Geography. 49 (2/4): 385–395. doi:10.2307/520904. JSTOR   520904.
  19. ↑ Bledsoe, Brian P.; Watson, Chester C. (2001-04-01). "Effects of Urbanization on Channel Instability1". JAWRA Journal of the American Water Resources Association. 37 (2): 255–270. Bibcode:2001JAWRA..37..255B. doi:10.1111/j.1752-1688.2001.tb00966.x. ISSN   1752-1688. S2CID   129927981.
  20. ↑ Chin, Anne (2006). "Urban transformation of river landscapes in a global context". Geomorphology. 79 (3–4): 460–487. Bibcode:2006Geomo..79..460C. doi:10.1016/j.geomorph.2006.06.033.
  21. ↑ Surian, Nicola (1999-11-01). "Channel changes due to river regulation: the case of the Piave River, Italy". Earth Surface Processes and Landforms. 24 (12): 1135–1151. Bibcode:1999ESPL...24.1135S. doi:10.1002/(sici)1096-9837(199911)24:12<1135::aid-esp40>3.0.co;2-f. ISSN   1096-9837.
  22. 1 2 Nilsson, Christer; Reidy, Catherine A.; Dynesius, Mats; Revenga, Carmen (2005-04-15). "Fragmentation and Flow Regulation of the World's Large River Systems". Science. 308 (5720): 405–408. Bibcode:2005Sci...308..405N. doi:10.1126/science.1107887. ISSN   0036-8075. PMID   15831757. S2CID   34820022.
  23. 1 2 3 4 Syvitski, James P. M.; Vörösmarty, Charles J.; Kettner, Albert J.; Green, Pamela (2005-04-15). "Impact of Humans on the Flux of Terrestrial Sediment to the Global Coastal Ocean". Science. 308 (5720): 376–380. Bibcode:2005Sci...308..376S. doi:10.1126/science.1109454. ISSN   0036-8075. PMID   15831750. S2CID   11382265.
  24. ↑ Lang, Andreas; Bork, Hans-Rudolf; Mäckel, Rüdiger; Preston, Nicholas; Wunderlich, Jürgen; Dikau, Richard (2003-11-01). "Changes in sediment flux and storage within a fluvial system: some examples from the Rhine catchment". Hydrological Processes. 17 (16): 3321–3334. Bibcode:2003HyPr...17.3321L. doi:10.1002/hyp.1389. ISSN   1099-1085. S2CID   128549460.
  25. ↑ Bay, Steven M.; Vidal-Dorsch, Doris E.; Schlenk, Daniel; Kelley, Kevin M.; Maruya, Keith A.; Gully, Joseph R. (2012-12-01). "Integrated coastal effects study: Synthesis of findings". Environmental Toxicology and Chemistry. 31 (12): 2711–2722. doi:10.1002/etc.2007. ISSN   1552-8618. PMID   22987611. S2CID   29470135.
  26. ↑ Gellis, A.C., Hupp, C.R., Pavich, M.J., Landwehr, J.M., Banks, W.S.L., Hubbard, B.E., Langland, M.J., Ritchie, J.C., Reuter, J.M. (2009). "Sources, transport, and storage of sediment at selected sites in the Chesapeake Bay watershed" (PDF). U.S. Geological Survey Scientific Investigations Report. 5186: 95 pp.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  27. ↑ Hupp, Cliff R.; Pierce, Aaron R.; Noe, Gregory B. (2009-06-01). "Floodplain geomorphic processes and environmental impacts of human alteration along Coastal Plain rivers, USA". Wetlands. 29 (2): 413–429. doi:10.1672/08-169.1. ISSN   0277-5212. S2CID   26811741.
  28. 1 2 3 4 5 6 7 Wohl, Ellen (2015). "Legacy effects on sediments in river corridors". Earth-Science Reviews. 147: 30–53. Bibcode:2015ESRv..147...30W. doi:10.1016/j.earscirev.2015.05.001.
  29. ↑ Hartranft, J., Merritts, D., Walter, R. (2006). "Legacy Sediment Definitions".{{cite web}}: CS1 maint: multiple names: authors list (link)
  30. ↑ James, L.A. (2013). "13.4 Impacts of Early Agriculture and Deforestation on Geomorphic Systems". Treatise on Geomorphology. pp. 48–67. doi:10.1016/b978-0-12-374739-6.00342-0. ISBN   9780080885223.
  31. ↑ Griffiths, G.A. (1979). "Recent sedimentation history of the Waimakariri River, New Zealand". Journal of Hydrology (New Zealand). 18: 6–28.
  32. ↑ Knox, J.C. (1972). "Valley alluviation in Southwestern Wisconsin". Annals of the Association of American Geographers. 62 (3): 401–410. doi:10.1111/j.1467-8306.1972.tb00872.x.
  33. ↑ Knox, J.C. (1977). "Human impacts on Wisconsin stream channels". Annals of the Association of American Geographers. 77 (3): 323–342. doi:10.1111/j.1467-8306.1977.tb01145.x.
  34. ↑ James, L.A. (2010). "Secular sediment waves, channel bed waves, and legacy sediment". Geography Compass. 4–6 (6): 576–598. doi:10.1111/j.1749-8198.2010.00324.x.
  35. ↑ "Colluvium".
  36. ↑ "Alluvium".
  37. ↑ Fryirs, Kirstie A.; Brierley, Gary J. (2012). Geomorphic Analysis of River Systems. John Wiley & Sons, Ltd. pp. 297–319. doi:10.1002/9781118305454.ch14. ISBN   9781118305454.
  38. ↑ Fryirs, Kirstie (2013-01-01). "(Dis)Connectivity in catchment sediment cascades: a fresh look at the sediment delivery problem". Earth Surface Processes and Landforms. 38 (1): 30–46. Bibcode:2013ESPL...38...30F. doi:10.1002/esp.3242. ISSN   1096-9837. S2CID   129141855.
  39. ↑ Hooke, R.L. (2000). "On the history of humans as geomorphic agents" (PDF). Geology. 28 (9): 843–846. Bibcode:2000Geo....28..843L. doi:10.1130/0091-7613(2000)28<843:OTHOHA>2.0.CO;2.
  40. ↑ Graf, William L. (2006). "Downstream hydrologic and geomorphic effects of large dams on American rivers". Geomorphology. 79 (3–4): 336–360. Bibcode:2006Geomo..79..336G. doi:10.1016/j.geomorph.2006.06.022.
  41. ↑ Graf, W.L. (2010). "Damage control: restoring the physical integrity of America's rivers". Annals of the Association of American Geographers. 91: 1–27. doi:10.1111/0004-5608.00231. S2CID   129837775.
  42. ↑ Westbrook, Cherie J.; Cooper, David J.; Baker, Bruce W. (2006-06-01). "Beaver dams and overbank floods influence groundwater–surface water interactions of a Rocky Mountain riparian area". Water Resources Research. 42 (6): W06404. Bibcode:2006WRR....42.6404W. doi: 10.1029/2005wr004560 . ISSN   1944-7973. S2CID   55251660.
  43. ↑ Meade, R.H., Moody, J.A. (2010). "Causes for the decline of suspended-sediment discharge in the Mississippi River system, 1940–2007". Hydrological Processes. 24: 35–49.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  44. ↑ Wayne., Trimble, Stanley (2013). Historical agriculture and soil erosion in the upper Mississippi Valley hill country. Boca Raton: Taylor & Francis. ISBN   9781466555747. OCLC   821611714.{{cite book}}: CS1 maint: multiple names: authors list (link)
  45. ↑ McClain, Michael E.; Boyer, Elizabeth W.; Dent, C. Lisa; Gergel, Sarah E.; Grimm, Nancy B.; Groffman, Peter M.; Hart, Stephen C.; Harvey, Judson W.; Johnston, Carol A. (2003-06-01). "Biogeochemical Hot Spots and Hot Moments at the Interface of Terrestrial and Aquatic Ecosystems". Ecosystems. 6 (4): 301–312. doi:10.1007/s10021-003-0161-9. ISSN   1432-9840. S2CID   12370754.
  46. ↑ Nowell, L.H., Capel, P.D., Dileanis, P.D. (2000). "Pesticides in stream sediment and aquatic biota: current understanding of distribution and major influences" (PDF). U.S. Geological Survey Fact Sheet. 092–00.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  47. ↑ Schumm, S.A. (1969). "River metamorphosis". Proceedings of the American Society of Engineers, Journal of the Hydrology Division. 1: 255–273.
  48. ↑ Klimek, K. (1987). "Man's Impact on Fluvial Processes in the Polish Western Carpathians". Geografiska Annaler: Series A, Physical Geography. 69 (1): 221–226. doi:10.1080/04353676.1987.11880209.
  49. ↑ Yaru, B.T., Buckney, R.T. (2000). "Metal interactions in contaminated freshwater sedi- ments from the Fly River floodplain, Papua New Guinea". International Journal of Environmental Studies. 57 (3): 305–331. doi:10.1080/00207230008711276. S2CID   98280627.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  50. ↑ Day, Geoff; Dietrich, William E.; Rowland, Joel C.; Marshall, Andrew (2008-03-01). "The depositional web on the floodplain of the Fly River, Papua New Guinea". Journal of Geophysical Research: Earth Surface. 113 (F1): F01S02. Bibcode:2008JGRF..113.1S02D. CiteSeerX   10.1.1.520.4858 . doi:10.1029/2006jf000622. ISSN   2156-2202.
  51. ↑ James, L.A. (1989). "Sustained storage and transport of hydraulic gold mining sediment in the Bear River, California". Annals of the Association of American Geographers. 79 (4): 570–592. doi:10.1111/j.1467-8306.1989.tb00277.x.
  52. ↑ Lu, X.x.; Zhang, Shurong; Xu, Jianchu (2010-05-01). "Climate change and sediment flux from the Roof of the World". Earth Surface Processes and Landforms. 35 (6): 732–735. doi:10.1002/esp.1924. ISSN   1096-9837. S2CID   129480452.
  53. ↑ Westerling, A. L.; Hidalgo, H. G.; Cayan, D. R.; Swetnam, T. W. (2006-08-18). "Warming and Earlier Spring Increase Western U.S. Forest Wildfire Activity". Science. 313 (5789): 940–943. Bibcode:2006Sci...313..940W. doi: 10.1126/science.1128834 . ISSN   0036-8075. PMID   16825536.
  54. ↑ Oswood, M. W.; Milner, A. M.; Irons, J. G. (1992). Global Climate Change and Freshwater Ecosystems. Springer, New York, NY. pp. 192–210. doi:10.1007/978-1-4612-2814-1_9. ISBN   9781461276814.
  55. ↑ Kondolf, G.M., Rubin, Z.K., Minear, J.T. (2014). "Dams on the Mekong: cumulative sediment starvation". Water Resources Research. 50 (6): 5158. Bibcode:2014WRR....50.5158K. doi:10.1002/2013WR014651. S2CID   128408857.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  56. ↑ Kesel, R.H. (2003). "Human modifications to the sediment regime of the Lower Mississippi River flood plain". Geomorphology. 56 (3–4): 325–334. Bibcode:2003Geomo..56..325K. doi:10.1016/s0169-555x(03)00159-4.
  57. ↑ Brooks, Andrew P; Brierley, Gary J; Millar, Robert G (2003). "The long-term control of vegetation and woody debris on channel and flood-plain evolution: insights from a paired catchment study in southeastern Australia". Geomorphology. 51 (1–3): 7–29. Bibcode:2003Geomo..51....7B. doi:10.1016/s0169-555x(02)00323-9.
  58. ↑ Lucas, C. (2001). "The Baia Mare and Baia Borsa accidents: cases of severe transboundary water pollution". Environmental Policy and Law. 31: 106–111.
  59. ↑ Rodbell, Donald T.; Delman, Erin M.; Abbott, Mark B.; Besonen, Mark T.; Tapia, Pedro M. (2014). "The heavy metal contamination of Lake Junín National Reserve, Peru: An unintended consequence of the juxtaposition of hydroelectricity and mining". GSA Today: 4–10. doi:10.1130/gsatg200a.1.
  60. ↑ Dubrovsky, N.M., Burow, K.R., Clark, G.M., Gronberg, J.M., Hamilton, P.A., Hitt, K.J., Mueller, D.K., Munn, M.D., Nolan, B.T., Puckett, L.J., Rupert, M.G., Short, T.M., Spahr, N.E., Sprague, L.A., Wilber, W.G. (2010). The quality of our nation's water — nutrients in the nation's streams and groundwater, 1992–2004. U.S. Geological Survey Circular 1350, Denver, CO.{{cite book}}: CS1 maint: multiple names: authors list (link)
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.