Land Use, Erosion, and Sedimentation in Aquatic Ecosystems: Laws and Science in the Cross-hairs

Baillie Bank Erosion

Controversy/Problem?

Erosion in Maine

Examples and Situations

1. In Arctic communties, the water levels are greatly decreasing along with the availability of fresh water. The fresh water is becoming very limited due to the algae/vegetation growth and sedimentation. Also, the high levels of precipitation have increased the occurence of landslides/mudslides. The melting of permafrost has been linked to erosion threatening buildings, transportation, waste disposal structures, and water supplies. Lastly, some of the water now contains heavy metals and other chemicals naturally bleached from the land. (Inuit Tapiriit Kanatami, 2007)

2. In Florida Bay, the water once consisted of seagrasses in clear water. Now, the murky waters are dominated with algae and stirred-up sediments. Also, there are no longer large grazers (sea turtles and manatees) swimming along these waters. The recruitment and settlement of fucoid plants are hindered due to the sedimentation caused by excessive phytoplankton production. Moreover, the overtake of algae in the water have increased nutrient and sediment runoff from land. Regime shifts have also occurred because of erosion by echinoids and overgrazing by fod-limited sea urchins. (Folke & Carpenter & Walker, 2004)

Runoff from Chesapeake Bay

3. In Bangladesh, disasterous floods are wiping out 10,117 hectares of land each year. Similarly, the Jamuna River erodes vast tracks along its course. (Roy, 2004)

4. The Conasauga River Watershed, between northern Georgia and southern Tennessee, is currently considered to be of the few wild and scenic rivers. Some large cities even use it as a source of drinking water. However, the river is experiencing a great amount of sedimentation from the erosion of agricultural lands, streambanks, development, and gravel and forest roads. (Riedal & Vose, n.d.)

5. Through naturally occurring proccesses, mercury can be converted to methylmercury, a potent nerotoxin in aquatic ecosystems. This could cause further complication in human and wildlife health. (USGS, 1994)

Methods/Initiatives To Help

1. Buffer strips between roads and streams tend to reduce the amount of sediments reaching the streams. However, this method would not help much in the case of a landslide. It would mostly be effective for culverts and roadside ditches. Good road location, and good ecological design of roadsides with regards to slope, soil, and hydrology would prove more effective. (Forman & Alexander, 1998)

2. Instead of constructing expensive detention ponds and drainage structures, creative grassland designs by roads may provide both sponge and biodiversity benefits. Certain grassland designs will be more resistant than aquatic organisms to road impacts. Moreover, this technique would show to be much less expensive. (Forman & Alexander, 1998)

3. To moniter bank-line changes based on annual river trends, CEGIS use satellite images to observe geomorphological developments and bank erosion along the Jamuna River. If the shifts of the river could be predicted, then embarkments could be set up in order to protect the surrounding areas. (Roy, 2004)

4. The Sediment Tool, an erosion model, aids in making decisions with repect to the restoration of forest roads. This model was developed by the EPA in order to generate estimates of soil erosion, sediment routing, and sediment yield. The Sediment Tool currently uses the universal soil loss equation to estimate soil erosion as well as sediment yield equations to transport sediment. To improve this model, an adaptation of the process-based Water Erosion Prediction Project model will reveal a finer DEM resolution and will show a more accurate representation of the road surfaces. (Riedal & Vose, n.d.)

5. Recycled material, such as compost, is used to prevent erosion. This method provides environmental, economic, and performance benefits. The EPA has awarded the largest Clean Water Act grant in respect to this idea. Using compost, has proved to filter water runoff while still retaining sediment. (Cogburn & Barrie & McCoy, 2003)

Pictures/Images