Construction activities on farms require a written Erosion and Sedimentation (E&S) Control Plan when disturbing more than 5,000 sq. ft., as with any other type of construction (residential, commercial, industrial, etc.). For activities that are less than 5,000 sq. ft., Best Management Practices (BMPs) need to be installed to minimize erosion and sedimentation, as well as to conserve your farm’s natural resources. NPDES Permits are required for planned disturbances of over 1 acre when building structures such as barns, manure storages, houses, silos, bunk silos, etc. Permits are to be issued prior to commencement of earthmoving. Normal plowing and tilling and the installation of BMPs such as waterways, barnyard improvements and animal walkways may not need an NPDES Permit or construction E&S plan as long as those activities are included and addressed in the farms Ag E&S Plan. As with any construction, activities in or around streams and wetlands may require additional approvals.