Cost Effectiveness of BMPs
Knowing the BMPs that are most effective and have the lowest cost makes it possible to develop an effective plan.
Identify Cost-Effective BMPs for Improving Water Quality and Maximizing Co-Benefits
This presentation discusses an approach to help you identify some of the most cost-effective practices for meeting permit requirements and TMDL reductions. Learn which BMPs are least expensive and provide high nutrient reductions, while addressing co-benefits like bacteria reduction.
BMP Pounds Reduced and Costs
The typical pounds of nitrogen, phosphorus, and sediment reduced for every BMP are provided in the two spreadsheets below at the county and state scales. These data are presented in terms of an acre of BMP, or the appropriate unit for the BMP like animal units, feet or acres treated. We also provide the cost of each BMP, and the cost per pound reduced. These data differ by geographical area since there are variable landscape characteristics. To determine the most cost effective BMP, simply filter the table for your geographic area, then sort the table on the cost per pounds reduced for the targeted pollutant.
BMP Pounds Reduced and Costs by County
The chart provided below offers a quick look at the average nitrogen or phosphorus load reduced per sector and the average cost per pound reduced per sector.
This information is provided to show the relative impact of each BMP. BMPs have a non-linear cascading effect. As a result, your scenario will not show identical load reductions as the table. The actual load reductions depend on the specific BMPs in your scenario, the base conditions for land use, and year. The data do show the relative effectiveness difference among the BMPs.
Cost per Pound Reduced per Extra Unit
The chart provided below shows the marginal load reduction and associated cost per pound reduced with 10 units of the BMP, 100 units, 1,000 units, and 10,000 units. You can view the data by sector, BMP name, and county. Phosphorus data coming soon.
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 2018 dollars. Costs are those incurred by both public and private entities. Technical assistance is not included in costs. Costs are for all BMPs in a scenario, both those currently implemented and those planned.
There are two cost formulas. For Total Annualized Cost, capital and opportunity costs are amortized over the BMP lifespan and added to annual operations and maintenance (O&M) cost. The interest rate for capital and opportunity costs is 5%. Costs represent a single year of cost rather than the cost over the entire lifespan of the practice. Total Annualized Costs are annualized average costs per unit of BMP (e.g.: $/acre treated/year). These costs are for a single year, and are not accumulated over time. The reason is two-fold. First, once the Bay TMDL deadline of 2025 is met, BMPs will need to remain in place to control loads and new BMPs will need to be implemented to offset new growth. Second, it is difficult to predict when a BMP is going to be implemented. Using this cost formula makes evaluations of costs among scenarios more comparable. The Total Annualized Cost 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)
For Total Implementation Cost, the entire capital cost and one year of opportunity cost are summed. Total Implementation Cost does not consider life cycle costs. The formula is capital + land. You may specify this formula in Cost Profiles once logging in. The Total Annualized Cost is provided below.
Edit Cost Profiles
You can log into CAST and edit the costs by creating your own Cost Profile. CAST provides costs associated with each scenario using the cost profile you select. The data available in the Cost Profiles is summarized to include the capital, operations and maintenance, and opportunity costs, depending on which cost formula you select.
BMP costs included in CAST are developed by contractors to the EPA and are in 2018 dollars.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 all BMPs are provided in the downloadable files below by sector.