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Development of a runoff trading system to meet watershed-level stormwater management goals with parcel-level green infrastructure
Citation:
Fu, X., M. Hopton, X. Wang, AND H. Goddard. Development of a runoff trading system to meet watershed-level stormwater management goals with parcel-level green infrastructure. AAG Annual Meeting, Washington, DC, April 03 - 07, 2019.
Impact/Purpose:
The research addresses issues related to the Clean Water Act and proposes a mechanism to facilitate the calculation and allocation of stormwater runoff allowances, assist with the decision-making of GI investment, and manage and update the allowance pool. The system is applicable to local, state, regional, tribal, and federal partners responsible for managing 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 government 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 requires, in part, a watershed-based planning framework, and fully informed parcel owners for tradable allowances, costs, and benefits. We propose a scenario-based Stormwater Management Planning Support System for Runoff Allowance Trading (SMPSS-RAT) to facilitate the calculation and allocation of stormwater runoff allowances, assist with the decision-making of GI investment, and manage and update the allowance pool. We apply the SMPSS-RAT to a sub-watershed located in Hamilton County, Ohio, USA and develop five scenarios representing increased use of GI. We test the scenarios under a 5-year rainfall intensity and set the cap at non-development level. SMPSS-RAT indicates the watershed authority should encourage all parcel owners to install suitable GI (rain barrels, rain gardens, and porous pavements), or purchase allowances 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 starts to reach the market equilibrium and generates 15,358 m3 allowance surplus.