Thursday, October 25, 2018

Moving the Goal in the Chesapeake Bay Cleanup

The entire Chesapeake Bay watershed is under a federal mandate to reduce sediment and fertilizer runoff into the bay in order to improve water quality. Excess nitrogen, phosphorus and sediment from waste water treatment plants, agriculture, urban and suburban runoff, septic systems, air pollution and other sources have impaired the Chesapeake Bay and its tidal waters. These pollutants cause algae blooms that consume oxygen and create dead zones where fish and shellfish cannot survive, block sunlight that is needed for underwater grasses, and smother aquatic life on the bottom.

The EPA set a limit for release of nutrients into the Chesapeake Bay watershed. This limit is called a TMDL and under the recently revised model is of 201,413,934 pounds of nitrogen, 14,174,003 pounds of phosphorus and 6.45 billion pounds of sediment per year which was about 25% reduction in nitrogen, 24% reduction in phosphorus and 20 % reduction in sediment from the 2011 levels. The pollution limits were then partitioned to the various states and river basins based on the Chesapeake Bay computer modeling tools and monitoring data.

To keep efforts on track, the EPA also required states to develop detailed plans and set interim two-year cleanup goals, which are evaluated by EPA. The plans were supposed it ensure that by 2017, the halfway point, 60% of the needed cleanup actions would be accomplished. In 2017 the EPA completed the midpoint assessment of the Chesapeake Bay. At the mid-point assessment the EPA’s Chesapeake Bay Program found that overall “Virginia has made progress in wastewater and agriculture, but needs to improve stormwater cost-share programs, account for growth in poultry farming, and strengthen MS4 requirements.”

Right now Virginia and all the other Bay states have begun work on the third and final iteration of their clean-up plans. These plans will describe actions to take, between now and 2025. The EPA has just completed the 6th revision to the Chesapeake Bay Model and issued revised cleanup goals, or “planning targets,” as the regulators like to call them. The revised model uses improved land cover data, new information about soil types and better information about nutrient movement through rivers as well as updated data about fertilizer sales, animal populations and the implementation and effectiveness of “best management practices” to reduce pollution.

The updates to the model shows less nitrogen reductions achieved from non-point sources than we previously thought. Now the model recognizes the importance of where nutrients are generated. Nutrient reductions from the Potomac River basin have greater impact on Bay health in the latest version of the model. Below are the revised goals. Note that West Virginia and Washington DC have already achieved their goals.


Virginia has made substantial progress towards addressing pollution to satisfy the Chesapeake Bay  goals, we have already met the phosphorus target, but still have work to do in nitrogen. Most of our progress comes from upgrades to wastewater treatment plants but also in agriculture. There has also been progress reducing polluted runoff from urban and suburban areas, although any progress has been overshadowed by increased land conversion from agricultural to suburban and residential and an increase in releases from septic systems. Virginia exceeded its 2017 goals largely because of the money spent on upgrade to its wastewater treatment plants. However, now the hard work of addressing all non-point pollution sources needs to be done. To succeed it is necessary for all to practice conservation and good land management. We all need to start in our own yards. 

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