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Development of a runoff trading system to meet watershed-level stormwater management goals with parcel-level green infrastructure - San Diego
Citation:
Fu, X., M. Hopton, X. Wang, H. Goddard, AND H. Liu. Development of a runoff trading system to meet watershed-level stormwater management goals with parcel-level green infrastructure - San Diego. ESRI User Conference, San Diego, CA, July 08 - 12, 2019.
Impact/Purpose:
Economic incentives and market-based mechanisms may encourage public participation in a decentralized approach to managing stormwater by installing GI on private parcels. This manuscript proposes a scenario-based planning support system to provide a platform for stormwater trading, and includes a tradable credits calculator that calculates and allocates runoff abatement credits. Such market-based mechanisms can help communities, states, and regions manage stormwater.
Description:
Green infrastructure (GI) has been recommended and adopted widely to reduce runoff from the built environment. Reliance on public land for GI implementation causes a heavy financial burden on local governments as they manage stormwater. Economic incentives and market-based mechanisms may encourage public participation in a decentralized approach to managing stormwater by installing GI on private parcels. However, a runoff trading market has not fully developed in practice. To establish a market, in part, requires a watershed-based planning framework, and fully informed parcel owners for tradable credits, costs, and benefits. We propose a scenario-based Stormwater Management Planning Support System for Trading Runoff Abatement Credits (SMPSS-TRAC) to facilitate the calculation and allocation of stormwater runoff abatement credits, assist with the decision-making of GI investment, and manage and update the credit pool. We apply SMPSS-TRAC to a sub-watershed located in Hamilton County, Ohio, USA and develop five extreme scenarios representing increasing use of GI. We test the scenarios under a 5-year rainfall intensity and set the cap at the non-development level of stormwater runoff. Under such conditions, SMPSS-TRAC indicates the watershed authority should encourage all parcel owners to install suitable GI (rain barrels, rain gardens, and porous pavements), or purchase credits from the market. In addition, the watershed authority would need to build detention basins on vacant lots and share costs and detention capacity with all parcels within the same sub-catchment to meet stated goals. By installing these four types of GI in the last scenario, the watershed reaches market equilibrium and generates 15,358 m3 credit surplus. SMPSS-TRAC has the potential for including multiple stakeholders’ preferences and concerns in searching for preferable scenarios.