Wikipedia

Urban stream

An urban stream is a formerly natural waterway that flows through a heavily populated area. Often times, urban streams are low-lying points in the landscape that characterize catchment urbanization.[1] Urban streams are often polluted by urban runoff and combined sewer outflows.[2] Water scarcity makes flow management in the rehabilitation of urban streams problematic.[3]

Second River, an urban stream in Orange, New Jersey

Description

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Some urban streams, such as the Hobart Rivulet in Tasmania, run underground for substantial distances

Governments may alter the flow or course of an urban stream to prevent localized flooding by river engineering: lining stream beds with concrete or other hardscape materials, diverting the stream into culverts and storm sewers, or other means. Some urban streams, such as the subterranean rivers of London, run completely underground. These modifications have often reduced habitat for fish and other species, caused downstream flooding due to alterations of flood plains, and worsened water quality.[4]

Stressors

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Toxicants, ionic concentrations, available nutrients, temperature (and light), and dissolved oxygen are key stressors to urban streams.[5]

Restoration efforts

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Some communities have begun stream restoration projects in an attempt to correct the problems caused by alteration, using techniques such as daylighting and fixing stream bank erosion caused by heavy stormwater runoff.[6][7] Streamflow augmentation to restore habitat and aesthetics is also an option, and recycled water can be used for this purpose.[8][9]

Urban stream syndrome

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Urban stream syndrome (USS) is a consistent observed ecological degradation of streams caused by urbanization. This kind of stream degradation is commonly found in areas near or in urban areas. USS also considers hydrogeomorphology changes which are characterized by a deeper, wider catchment, reduced living space for biota, and altered sediment transport rates. Keep in mind the status of water quality is difficult to assess in urban areas because of the complexity of the pollutions sources.[10] This could be from mining and deforestation, but the main cause can be attributed to urban and suburban development. This is because such land use has a domino effect that can be felt tens of kilometers away. Consistent decrease to ecological health of streams can be from many things, but most can be directly or indirectly attributed to human infrastructure and action. Urban streams tend to be "flashier" meaning they have more frequent and larger high flow events.[2][11]

Urban streams also suffer from chemical alterations due to pollutants and waste being uncleanly dumped back into rivers and lakes. An example of this is Onondaga Lake. Historically one of the most polluted freshwater lakes in the world, its salinity and toxic constituents like mercury rose to unsafe levels as large corporations begun to set up shop around the lake. High levels of salinity would be disastrous for any native freshwater marine life and pollutants like mercury are dangerous to most organisms.[12]

Higher levels of urbanization typically mean a greater presence of urban stream syndrome.[13]

Hydrology plays a key role in urban stream syndrome. As urbanization of these streams continue, there is in turn a decrease in the perviousness of the catchment to precipitation, which leads to a decrease in the infiltration and an increase in the surface runoff. This can cause problems during flood discharges. For example, flood discharges in urban catchments were at least 250% higher in urban catchments than in forested catchments in New York and Texas during similar storms.[14]

Treatment

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Many water managers treat USS by directly addressing the symptoms, most commonly through channel reconfiguration that includes reshaping rock to address altered hydrology and sediment regimes. In spite of having ecological objectives, this approach has been criticized for addressing physical failures in the system without improving ecological conditions.[15]

See also

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References

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  1. ^ Violin, Christy R. (September 2011). "Effects of urbanization and urban stream restoration on the physical and biological structure of stream ecosystems". Ecological Applications. 21 (6): 1932–1949. Bibcode:2011EcoAp..21.1932V. doi:10.1890/10-1551.1. JSTOR 41416629. PMID 21939035.
  2. ^ a b Walsh, Christopher J.; Roy, Allison H.; Feminella, Jack W.; Cottingham, Peter D.; Groffman, Peter M.; Morgan, Raymond P. (2005). "The urban stream syndrome: current knowledge and the search for a cure". Journal of the North American Benthological Society. 24 (3): 706–723. doi:10.1899/04-028.1. S2CID 30667397.
  3. ^ Lawrence, Justin E.; Pavia, Christopher P. W.; Kaing, Sereyvicheth; Bischel, Heather N.; Luthy, Richard G.; Resh, Vincent H. (2014). "Recycled water for augmenting urban streams in mediterranean-climate regions: a potential approach for riparian ecosystem enhancement". Hydrological Sciences Journal. 59 (3–4): 488–501. Bibcode:2014HydSJ..59..488L. doi:10.1080/02626667.2013.818221. S2CID 129362661.
  4. ^ National Management Measures to Control Nonpoint Source Pollution from Hydromodification (Report). Washington, DC: U.S. Environmental Protection Agency (EPA). July 2007. EPA 841-B-07-002.
  5. ^ Wenger, Seth J.; Roy, Allison H.; Jackson, C. Rhett; Bernhardt, Emily S.; Carter, Timothy L.; Filoso, Solange; Gibson, Catherine A.; Hession, W. Cully; Kaushal, Sujay S.; Martí, Eugenia; Meyer, Judy L.; Palmer, Margaret A.; Paul, Michael J.; Purcell, Alison H.; Ramírez, Alonso; Rosemond, Amy D.; Schofield, Kate A.; Sudduth, Elizabeth B.; Walsh, Christopher J. (December 2009). "Twenty-six key research questions in urban stream ecology: an assessment of the state of the science". Journal of the North American Benthological Society. 28 (4): 1080–1098. doi:10.1899/08-186.1. hdl:10919/80380. S2CID 23296920.
  6. ^ California Department of Water Resources. "Urban Streams Restoration Program". Retrieved 2009-07-11.
  7. ^ Revkin, Andrew C. (16 July 2009). "Rolling Back Pavement to Expose Watery Havens". New York Times. Retrieved 19 July 2009.
  8. ^ Bischel, Heather N.; Lawrence, Justin E.; Halaburka, Brian J.; Plumlee, Megan H.; Bawazir, A. Salim; King, J. Phillip; McCray, John E.; Resh, Vincent H.; Luthy, Richard G. (2013). "Renewing Urban Streams with Recycled Water for Streamflow Augmentation: Hydrologic, Water Quality, and Ecosystem Services Management". Environmental Engineering Science. 30 (8): 455–479. doi:10.1089/ees.2012.0201.
  9. ^ Halaburka, Brian J.; Lawrence, Justin E.; Bischel, Heather N.; Hsiao, Janet; Plumlee, Megan H.; Resh, Vincent H.; Luthy, Richard G. (2013). "Economic and Ecological Costs and Benefits of Streamflow Augmentation Using Recycled Water in a California Coastal Stream". Environmental Science & Technology. 47 (19): 10735–10743. Bibcode:2013EnST...4710735H. doi:10.1021/es305011z. PMID 23688175.
  10. ^ Duda, Alfred M. (July 1982). "Water Quality in Urban Streams: What We Can Expect". Water Pollution Control Federation. 54 (7): 1139–1147. JSTOR 25041633.
  11. ^ Vietz, Geoff J.; Walsh, Christopher J.; Fletcher, Tim D. (2016). "Urban hydrogeomorphology and the urban stream syndrome: Treating the symptoms and causes of geomorphic change". Progress in Physical Geography: Earth and Environment. 40 (3): 480–492. doi:10.1177/0309133315605048. S2CID 131397867.
  12. ^ Rowell, H. Chandler; Enache, Mihaela D.; Quinlan, Roberto; Smith, Alison J.; Bloomfield, Jay A.; Charles, Donald F.; Effler, Steven W. (2016). "Quantitative paleolimnological inference models applied to a high-resolution biostratigraphic study of lake degradation and recovery, Onondaga Lake, New York (USA)". Journal of Paleolimnology. 55 (3): 241–258. Bibcode:2016JPall..55..241R. doi:10.1007/s10933-015-9877-8. S2CID 130414481.
  13. ^ Brown, Larry R.; Cuffney, Thomas F.; Coles, James F.; Fitzpatrick, Faith; McMahon, Gerard; Steuer, Jeffrey; Bell, Amanda H.; May, Jason T. (2009). "Urban streams across the USA: lessons learned from studies in 9 metropolitan areas". Journal of the North American Benthological Society. 28 (4): 1051–1069. doi:10.1899/08-153.1. S2CID 85861111.
  14. ^ Paul, Michael J (2001). "Streams in the Urban Landscape". Annual Review of Ecology and Systematics. 32: 335. doi:10.1146/annurev.ecolsys.32.081501.114040. JSTOR 2678644.
  15. ^ Laub, Brian G.; Baker, Daniel W.; Bledsoe, Brian P.; Palmer, Margaret A. (2012). "Range of variability of channel complexity in urban, restored and forested reference streams: Channel complexity and stream restoration". Freshwater Biology. 57 (5): 1076–1095. doi:10.1111/j.1365-2427.2012.02763.x.

Bibliography

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