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Environmental Modeling Community of Practice

WMOST ScenCompare Documents

Impact Purpose

EPA's Watershed Management Optimization Support Tool (WMOST) facilitates the application of integrated water management to solve water quantity and water quality problems at least cost. The new Benefits Module will allow users to monetize additional water-quality related benefits (ecosystem service benefits, reduced drinking water treatment costs) and cobenefits (non-water quality endpoints) of management actions to meet water quality goals such as loading targets. Management actions to reduce pollutant loads can have ancillary benefits and co-benefits that stakeholders may wish to consider in the decision-making process. The benefits module allows users to monetize these and cobenefits for comparison with capital and operation and maintenance costs of management actions already incorporated into WMOST. WMOST can be used to calculate the cost-savings associated with integrated management, e.g., flood risk reduction, or reduced infrastructure costs associated with combined sewer overflow treatment as stormwater runoff is reduced. However, management actions to meet water quantity and water quality goals can have additional benefits as well, such as improved residential property values associated with increased green space, ecosystem services provided by surface water that are valued by humans (including water-based recreation, aquatic biodiversity, wildlife support, aesthetics, and non-use values, reduced exposure to air pollutants leading to human health benefits, avoided costs for drinking water treatment, and reduced energy usage for heating and cooling related to reduced costs and reduced emissions of air pollutants (and associated health benefits).


An updated version of the Scenario Comparison Tool (ScenCompare) has been developed that incorporates a Benefits Module for EPA’s Watershed Management Optimization Support Tool (WMOST). WMOST was developed by the United States Environmental Protection Agency (US EPA) to facilitate integrated water resources management. ScenCompare allows comparison and evaluation of any set of WMOST results to understand the effects of varying climate, land use, and other model inputs on the set of management actions selected by WMOST to meet the specified management goal at the lowest cost. The new Benefits Module for WMOST embedded within ScenCompare v. 2 enables stakeholders to calculate the value of additional water quality benefits associated with water resource management as well as additional co-benefits. Water quality benefits (or costs) include both changes in costs of drinking water treatment and total nonmarket benefits (i.e., use and nonuse) of water quality changes. Co-benefits valued include (1) change in housing property value due to improved aesthetic quality of the landscape from increases in green space, (2) air pollution removal and energy savings benefits related to canopy cover, and (3) air pollution removal and energy savings benefits related to green roofs.

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