By Wendy Powers
Total Maximum Daily Load, or TMDL, is the amount of a pollutant that can enter a water source with that water source still meeting a quality standard. As part of the TMDL development process, nutrient loads are allocated to the sources that contribute the pollutant to the water source. For example, Pollutants for which a TMDL are developed might include nutrients, sediment or bacteria.
The Chesapeake Bay area of the U.S. has received considerable attention over the last decade due to water quality concerns. As a result, the Environmental Protection Agency established a TMDL in the Chesapeake Bay back in 2010 that set limits for nitrogen, phosphorus and sediment with goals of reducing influx of these pollutants into the Bay by 25, 24 and 20 percent respectively, by 2025.
The Bay TMDL is now in the Watershed Implementation Plan (WIPs) phase. Each of 6 states in the region plus the District of Columbia have developed WIPs. At the heart of many of these plans are efforts to control runoff from non-permitted sources such as agricultural lands. This requires practice changes for many farmers in the Chesapeake Bay Watershed. Pollutant controls, practices and actions include barnyard runoff measures, conservation tillage, pasture grazing practices, grass buffers and nutrient management. Environmental organizations, universities, state and federal agencies and farmers are working together in a watershed partnership to implement changes and document impact.
Lamonte Garber from the Chesapeake Bay Foundation is part of that partnership, working with small family farms in Southeastern Pennsylvania to implement agricultural best management practices (BMPs) in association with restoration of forested riparian buffers. This project has demonstrated the potential to achieve multiple conservation objectives with producers who have typically avoided participation in such programs in the past. To hear more from Garber about this program consider attending Michigan State University Extension's Communities and Livestock workshop on April 23, 2013 in East Lansing. Garber will share his experiences and successes as part of the Chesapeake Bay Foundation's involvement in helping agriculture meet TMDL targets for the Bay watershed.
Many states across the U.S. are looking at TMDLs as a way to ensure that waters are fishable and/or swimmable. Adoption of on-farm practices that reduce or eliminate movement of pollutants to waters continues to be a primary focus of programs through Michigan State University Extension and our partners.
For more information, visit their website. To contact an expert in your area, visit online, or call 888-MSUE4MI (888-678-3464).
Powers writes from the Michigan State University Extension Office.