Refinement and Revision of Chesapeake Bay Program Best Management Practice (BMP) Efficiency Estimates

Funding: About $210,000 for 2006-2008 (two year project). The P.I. is Dr. Tom Simpson. Estimated water quality impacts of practice implementation and evaluation of different strategies for nutrient reductions are done using the Chesapeake Bay Watershed Model. Effectiveness estimates (formerly called efficiencies) are used for each BMP reported to the Chesapeake Bay Program. Original efficiencies were developed in 1993 and underwent minor revisions until 2003 when several BMP efficiencies were revised based on new data and implementation experience. It became evident that efficiencies were optimistic and actual water quality improvements were much less than estimated using the model and BMP efficiencies. This led to much public and media controversy and a series of reviews of the Chesapeake Bay Program by Congress, GAO and EPA and USDA Offices of Inspectors General. Dr. Tom Simpson was the senior author of the Scientific and Technical Advisory Committee white paper that identified the causes of the optimistic efficiency estimates and recommended a review and revision of BMP efficiencies.

Revision of effectiveness estimates for all BMPs reported to the Bay program prior to 2003 have been completed and we are beginning to develop standard definitions and literature based effectiveness estimates for all new and innovative BMPs proposed in the 2004 Tributary Strategies. Revising the existing efficiencies was a very high profile and contentious effort since state management and budgetary decisions are usually made based on the relative effectiveness of different practices. The use of the effectiveness estimates in nutrient credit trading and Total Maximum Daily Load regulatory programs added further attention and concern to the revision process. Although extremely difficult and contentious, we were able to gain consensus from the scientific and management communities on new, more realistic effectiveness estimates for all existing BMPs.

This project has illustrated the difficulty of applying adaptive scientific management when that science is directly used in policy, management and setting prices in the market.

For more information, contact Dr. Tom Simpson

Last updated: 02/7/2008