The Consequences of Wetland Drainage

In the 1660’s there was over 220 million acres of wetlands in the United States. Since then, over half have been destroyed. Wetlands act as a natural flood control and water filter, not to mention the biological diversity they contain; therefore, destroying them is like destroying part of our country. Civil Engineers have the ability and responsibility to stop the wetland destruction and reverse the effects.

Source: http://www.soil.ncsu.edu/publications/

The U.S. Environmental Protection Agency defines wetlands as “those areas that are inundated or saturated by surface or groundwater at a frequency and duration sufficient to support, and that under normal circumstances do support, prevalence of vegetation typically adapted for life in saturated soil conditions.” Wetlands include swamps, bogs, fens and marshes; all of which have biologically diverse ecosystems. As I mentioned earlier, wetlands provide a wide variety of useful functions. First, they operate as a water purification system. Wetlands allow water to filter out impurities so only clean water is added to the groundwater. Second, they provide a habitat for fish, wildlife and a variety of plants. Third, wetlands control flood waters and snow-melt  which they slowly release there-after. This provides a level of stability along coastal regions. So, as you can see, wetlands are a very valuable part of nature that needs to be preserved.

Source: http://mhsapeses4th.wikispaces.com/

Despite the benefits that wetlands provide, they are being drained and destroyed at an alarming rate. The top cause for their disappearance is wetland drainage. Wetland drainage is the act of removing the water from low-lying areas to convert the land for use in agriculture or housing. This kind of action is having and will have worsening consequences. Due to the removal of the water, groundwater isn't being replenished as efficiently and will start to undergo something known as groundwater mining. Groundwater is important because it is the source of drinking water for over 50% of the people in the U.S. Additionally, toxic compounds (such as urban and rural runoff) won’t get filtered out as well as if there were wetlands. This has the possibility of contaminating groundwater and making it unusable. Furthermore, wetlands are an effective way of controlling snow-melt and flooding. Without the wetlands, communities will be subject to repeated floods. Finally, wetland drainage has caused many species to become endangered (like the ­­­­­­black-faced spoonbill) or to even go extinct (like the pink-headed duck). This means wetland drainage is extinguishing the possibility of large-scale diversity.

Source: http://cooperativeconservation.org/

The U.S. government is doing research to try and reverse the effects of wetland drainage. Civil Engineers can help by participating in projects, like wetland restoration, which are taking place all across the U.S. Wetland restoration is done by initially flooding the land and over time the wetland vegetation will reestablish itself. However, bringing back lost wetland is not always that simple. Much of the area that used to be wetland was converted to agriculture which causes the soil to lose a lot of it nutrients, while also being changed by the application of fertilizers and pesticides. Therefore, as Write states, "the proper management of hydrologic conditions and vegetation are critical for reestablishment of wetlands." This is the perfect job for geotechnical and environmental civil engineers. 

So, as you can see, wetlands are a vital part of nature. They help us in countless ways and are essential to our society. Though the loss of wetlands has slowed over the year, the number of acres is still decreasing. It's up to civil engineers to stop wetland drainage and reverse the negative effects.

Source: http://www.fws.gov/kulmwetlands/wetlands.html