Cost Effectiveness Assessment

Cost-effectiveness indicates the pollutant load reduction per dollar spent on installing and maintaining BMPs. The project team developed the detailed information about individual BMPs at specific sites in the watershed or for representative farms. Information for individual BMP projects is scaled up to estimate watershed reductions in TP and sediment, and the total and annual costs at the watershed scale. The cost effectiveness of these BMPs in reducing TP and sediment is calculated by dividing the annual watershed cost by the reduction in TP and sediment in the Neshanic River Watershed.

Reductions in TP and sediment for the agricultural BMPs are based on the reduction rates from literature, the SWAT-estimated pollutant loads, and the land suitable for BMP implementation in the watershed. The scale-up for stormwater BMPs including rain gardens, roadside ditch retrofitting, detention basin retrofitting and vegetative buffers in developed lands is based on the information on the assessment unit, reduction rates for TP and sediment, and assessment costs in the stormwater BMP detail sheets on the site specific projects. The cost-effectiveness for those stormwater and agricultural BMPs measures the reduction in TP or sediment per $1,000 spent on the BMP in the watershed. The cost-effectiveness for the management measures to reduce the pathogen loads was measured differently by the program costs of implementing these BMPs for achieving one percent reduction in pathogen loads.

Progress and Status

  • completed by March 2011

Results and Outcomes

The BMPs are prioritized based on the BMP cost-effectiveness assessment results. The top 5 ranked BMPs for reducing TP loads are:

  1. Livestock access control;
  2. Nutrient management;
  3. Conservation buffers on agricultural lands;
  4. Contour farming; and
  5. Prescribed grazing.

The top 5 ranked BMPs for reducing sediment are:

  1. Vegetative buffers in developed lands;
  2. Livestock access control;
  3. Contour farming;
  4. Conservation buffers on agricultural lands; and
  5. Detention basin retrofitting.

The top 5 ranked BMPs for reducing pathogenic loads to the streams are

  1. Livestock access control;
  2. Livestock waste storage and composting structures;
  3. OSDS inspection and maintenance;
  4. Manure application incorporation technology; and
  5. Failed OSDS retrofitting.

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