Modeling the Value of Ecosystem Services: Application to Soil Loss in Southeastern Allegheny County

Abstract

Putting a price on environmental services could encourage sustainable development and make conservation more appealing. However, one of the difficulties in conservation is being able to quantify the cost of environmental services. The Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) modeling tool, created by the Natural Capital Project and Stanford University, works as a toolbox in Geographic Information Systems (ArcGIS). The model was used to determine the impact on environmental services, specifically soil erosion in southeastern Allegheny County, Pennsylvania. The Allegheny, Ohio and Monongahela Rivers all receive runoff from the surrounding area and have been negatively impacted by an increase in development. Annual soil loss due to erosion, and the associated economic cost, were estimated using the InVEST model and manual calculations. The maps for soils, slope and watersheds, were provided by Pennsylvania Spatial Data Access (PASDA), the digital elevation maps, and the land use, land cover maps were provided by the EPA. The estimated sediment load for the southeastern area of Allegheny County is 1024 tons/year, all from the Youghiogheny watershed, computed from the InVEST model. The cost of sediment removal is $129,024 per year. When using the Universal Soil Loss Equation for manual calculations, the sediment load ranges from 43,978 tons/year to 146,592 tons/year for the same study area that was used in InVEST.