Default unit cost estimates are provided for each state and the Chesapeake Bay Watershed. The Chesapeake Bay Watershed is an average of all states. Costs are provided as a starting point to use for creating your own cost estimates of various BMP scenarios. Costs are estimated in 2010 dollars. Capital and opportunity costs are amortized over the BMP lifespan and added to annual operations and maintenance (O&M) costs for a total annualized cost.
Costs are annualized average costs per unit of BMP (e.g.: $/acre treated/year). The formula is:
- annual costs = (capital * annualization factor) + O&M costs + (land * annualization rate)
- annualization factor = i/((1+i)^n - 1) + i
- i = annualization rate, which is always 5%
- n = period of annualization (also called lifespan)
BMP Cost Data Sources
BMP costs included in CAST are developed by contractors to the EPA and are in 2010 dollars. The costs are available by logging in to CAST and going to the Cost Profiles. There is a profile for each state. CAST users may edit costs to their liking and determine the cost for any scenario. The original costs were reviewed with the states who provided input. Additional BMPs were approved by the Chesapeake Bay Program Partnership since the original TMDL costs were determined. The data source of the original BMPs and the more recently added BMPs are provided in the downloadable files below.