Citation:

Chamberlin, C., M. Ten Brink, K. Munson, A. Le, AND N. Detenbeck. River Basin Export Reduction Optimization Support Tool; a tool to screen options for reducing nutrient loads while minimizing cost. JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION. American Water Resources Association, Middleburg, VA, 59(1):178-196, (2023). https://doi.org/10.1111/1752-1688.13070

Impact/Purpose:

Pollution by excess amounts of nitrogen and phosphorus causes water quality problems such as nuisance algal blooms in many waterbodies around the nation and world. Nitrogen and phosphorus are transported to waterbodies from agricultural areas (e.g. from fertilizer), from urban areas through stormwater runoff, from wastewater treatment plants, and from several other natural and human-caused sources. Numerous treatments and interventions exist that can remove nitrogen and phosphorus from water and soil before it reaches a river, improving water quality. Deciding where and how to treat this pollution is challenging. In this article we discuss a new decision support tool we have built that finds an ‘optimal’ solution (here, the lowest-cost solution) to the problem of choosing what treatments to build, and where. We use this support tool in the Upper Connecticut River basin, which carries nutrients into the Long Island Sound. Various optimal solutions for reducing the amount of nitrogen flowing out of the Upper Connecticut River basin by 10% will cost $19-$37 million each year over 15 years. This new decision support tool can be used anywhere in the northeastern USA, and future work will allow it to be used in other regions of the USA as well.

Description:

Excess loading of nitrogen and phosphorus to river networks causes environmental harm, but reducing loads from large river basins is difficult and expensive. We developed a new tool, the River Basin Export Reduction Optimization Support Tool (RBEROST) to identify the least-cost combinations of management practices that will reduce nutrient loading to target levels in downstream and mid-network waterbodies. We demonstrate the utility of the tool in a case study in the Upper Connecticut River Basin in New England, USA. The total project cost of optimized lowest-cost plans ranged from $18.0 million to $41.0 million per year over 15 years depending on user specifications. Plans include both point source and non-point source management practices, and most costs are associated with urban stormwater practices. Adding a 2% margin of safety to loading targets improved the estimated probability of success from 37.5% to 99%. The large spatial scale of RBEROST, and the consideration of both point and non-point source contributions of nutrients, make it well suited as an initial screening tool in watershed planning.

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