Agricultural non-point source pollution in Vermont and the use of constructed wetlands as a mitigative measure

Holland, Elise C.
Michael Simpson, MS
Department of Environmental Studies
Non-point source pollution has been identified by the Environmental Protection Agency (EPA) as a major contributor to water pollution concerns in Vermont and across this country. Three main sources of this type of pollution have been identified as: failed septic systems, urban stormwater runoff and agricultural wastewater and runoff. Non-point source pollution presents many problems as far as mitigation, treatment, and remediation are concerned. Vermont’s state government and governments across the country are beginning to realize that a lack of control over this type of pollution has serious deleterious effects on water quality. Of the three main contributors agriculture is the most detrimental and possibly the most difficult to remedy. The EPA has joined forces with Vermont state agencies in an effort to work to mitigate the proliferation of these contributing factors and likewise decrease the detrimental effects they have on surface and groundwater systems. Historically, agriculture has been exempt from regulations of many kinds in a conscious effort, on the part of the government, to support the agrarian economy. But things may be changing as the environmental effects of agricultural practices are recognized and their impacts measured. Intensive ro-cropping and heavily concentrated animal husbandry practices often result in soil erosion and nutrient-loaded runoff which impacts adjacent groundwater and surface water systems. Many farmers are forced, out of necessity, to farm land that is not in prime condition and apply fertilizers and pesticides in an effort to boost production or to clear woody and riparian vegetation in an effort to increase grazing area. This practice tends to exacerbate the problem of impacting aquatic systems by eliminating buffer-strip filtering areas which protect streams and other waterways from direct pollutant load. A means of prevention, mitigation and treatment is needed. Best Management Practices (BMPs) have been developed by agricultural agencies not only to educate farmers in the methods of sound agriculture but as part of a proactive effort to help preserve natural resources for future use. Constructed wetlands is an evolving technology, that dovetails with these other developments, all of which attempt to mitigate water pollution problems associated with agriculture. This new and innovative technology employs vegetation and natural processes in the removal of excess nutrients, pollutants and sediment from agricultural runoff and wastewater. These wetland systems can be designed to be site and pollutant specific and can be established at relatively low cost and with minimal site work. Research and investment into this alternative approach to wastewater treatment is growing and more is being learned from the results of similar applications in residential and municipal situations. There are many variables to consider when planning to implement BMPs and constructed wetlands but with careful consideration, planning, and monitoring they will be successful. Through the implementation of these mitigative and preventative measures land and water resources will be enhanced and preserved for future agricultural use.

Read Full Text