Benefits to downstream flood attenuation and water quality as a result of constructed wetlands in agricultural landscapes

The evolution of agricultural practices in America has a direct correlation with improvements in the mechanization of farm equipment and the development of transportation routes. As artificially constructed systems evolved, they were rigorously imposed on the natural landscape with little thought to their effect on the hydrologic system. Soggy fields and drowned crops were viewed as problems needing remediation. Flat, forested, fertile, bottomland was assumed to be unproductive and needed to “pay its way.” Deforestation, stream channelization, levees, field terracing, and drainage systems (drain tiles) have become testaments to our corrective actions. The cumulative effect of these corrective measures has been to significantly reduce the ability of most watersheds to absorb water, detain sediments, and remove nutrients. Our command and control approach to watershed management cannot necessarily be viewed as a success as evidenced by the flood of 1993 and 1995 in the Midwest and the fact that today, 30 percent of assessed U.S. surface waters do not “fully support” their designated uses (USEPA 1988). Because of our inadequate watershed management, the Federal Emergency Management Agency (FEMA) and other agencies have hinted that America's flood and water quality policies must change. The purchase …