...
(6) Soils and root systems filter nutrients and pollutants from runoff (especially from agriculture and residential areas) before they reach reach surface areas from groundwater waters (Haberstock, 2000). !DCP00013.JPG!The vegetation on the sides of this waterway is an example of a riparian buffer. Source: USGS
...
The width of the buffer depends on many factors, especially the slope of the land (steeper slopes require wider buffers, since steeper slopes allow water to flow faster and water's ability to carry sediments increases exponentially with volume (Chapman, 1996)), the permeability of the soil (less permeable soils require wider buffers because water takes longer to infiltrate), and the presence of overland water sources--like intermittent streams or gullies-which can render small buffers ineffective (Haberstock, 2000). The type of vegetation-such as wooded or ground level vegetation--as well as factors such as duff height can influence buffer efficacy (Haberstock, 2000). Buffer width is measured from the floodplain edge (Haberstock, 2000). Haberstock also notes that wetlands in these areas should be preserved, because they serve to fix nitrogen and retain contaminants and sediments; the issue of wetlands preservation is detailed on another page (LINK TO WETLANDS PAGE?). Ideally, a consult should be taken to determine the ideal width for an area.
However, if it is not economically feasible to establish a buffer of the recommended width, it is still beneficial to establish a riparian buffer of a smaller width. Studies have found that buffers of 20 feet of native grasses can remove up to 90% of nutrients and 80% of sediments in agricultural areas (Lutz). Furthermore, a riparian buffer does not mean that no human activity or industry can take place in these zones; for example, selective logging can take place if best-management practices are followed (for example, see http://mdc4.mdc.mo.gov/documents/441.pdfpages 5-21) and some agricultural activities such as growing nut trees can easily serve as a buffer and a source of income.
...
Special attention should be given to wetlands that are unique, host rare species, or perform important functions. An example of this type of prioritization can be seen in the Ramsar Convention's Wetlands of International Importance list (http://www.ramsar.org/about/info2007-05-e.pdffor criteria).To protect fish, the destruction of wetlands should be stopped and ecologically necessary wetlands should be restored. While the lack of them is common across the globe, the need for specific ones and often the destruction of them due to natural disasters or human interference varies with location. Thus an important compilation of both local task forces, primarily lead by wetlands international (a compilation of regional offices and groups) assisted by and encouraged by laws and regulations is the best solution. Organizations like Wetlands International play a particularly important role in this setup because they both organize the needed local tasks forces and catalyze the political action process. Wetlands International's mission statement serves to clarify its duality in its proposal that it "works in local areas to help create restoration programs combined with stricter enforcement," (Finlayson, 2006).
A similar tactic should be employed for coral reef protection, especially with regards to regulation of destructive practices. Coral reefs should be given top priority in terms of aquatic resource protection. Educational efforts should also be expended to encourage public support for coral reef protection; education in this sector should be effective considering the immense beauty and intrinsic value of these areas. Other unique and critical habitats should be afforded specific legislative protection as well.
...
For dams that have not yet been built there are many steps that can be taken to minimize the impacts. First, efforts should be made to increase energy and water efficiency as much as possible; in the past, increases in technological efficiency, recycling, enforcement of environmental legislation, and reduction of industrial water use allowed water consumption to grow much slower than population (WCD). However, if a dam is definitely needed, research should be conducted to determine its environmental impacts. The World Commission on Dams reports that many of the negative impacts are not foreseen; it predicts that use of environmental impact assessments could significantly reduce these effects (WCD). Furthermore, proper placement of dams (such as on tributaries rather than on a main branch) and the use of minimal numbers of dams on a given river (because multiple dams can have cumulative effects, such as the dams leading to the Aral sea, which decreased water flow to such an extent that an increase in salinity and pollutants caused the entire fishery to collapse at a cost of approximately $1.25-2.5 billion per year) should be required by governments as such restrictions can minimize the large-scale negative impacts of large dams (WCD). Once these data are collected, the dam planning may begin; in this way, the dam design can take into account such features as gates that allow managed flood releases on a scale that can mitigate effects to the ecosystem; the permit for dam construction can require these provisions. The use of such managed floods in Kenya has been economically favorable by maintaining sectors of the economy that relied upon flows that would have been blocked entirely by damming (WCD). These floods help to release nutrients and sediments and help lessen the impact of the dam overall (WCD). These managed floods should be tailored to a specific river, as flood cycles are highly unique. It is important, however, that all such planning occurs before dam construction, as post-construction mitigation techniques have not been shown to be effective; the WCD reports rates of 20% effectiveness. It is possible that the IFIM (Instream Flow Incremental Methodology), as described earlier in (LINK TO WATER QUALITY ASSESSMENT AND LEGISLATION) could be used to help predict the effects of a dam and the effects of controlled flooding. !damphoto.gif!Source: USGS
...