Urban stream

An urban stream is a formerly natural waterway that flows through a heavily populated area. Urban streams are often polluted by urban runoff and combined sewer outflows.[1] Water scarcity makes flow management in the rehabilitation of urban streams problematic.[2]

Second River, an urban stream in Orange, New Jersey

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.[3]

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

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.[4][5] Streamflow augmentation to restore habitat and aesthetics is also an option, and recycled water can be used for this purpose.[6][7]

Urban stream syndrome

Urban stream syndrome (USS) is defined as 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. 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.[1][8]

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.[9]

Higher levels of urbanization typically mean a greater presence of Urban Stream Syndrome. [10]

Treatment for urban stream syndrome

Many water managers treat USS by directly addressing the symptoms. This approach has been criticized for being sensitive to physical failure and a lack of success in improving ecological conditions. This common approach is called channel reconfiguration which includes reshaping rock to address altered hydrology and sediment regimes. Although this approach does have ecological objectives, some studies show that it does not lead to ecological stream improvement.[11]

See also

References
  1. 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.
  2. 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. doi:10.1080/02626667.2013.818221. S2CID 129362661.
  3. 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.
  4. California Department of Water Resources. "Urban Streams Restoration Program". Retrieved 2009-07-11.
  5. Revkin, Andrew C. (16 July 2009). "Rolling Back Pavement to Expose Watery Havens". New York Times. Retrieved 19 July 2009.
  6. 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.
  7. 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.
  8. 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.
  9. 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. doi:10.1007/s10933-015-9877-8.
  10. 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.
  11. 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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