Rainwater Harvesting in a Common Pool Resource: An Engineering Perspective

Abstract

Water scarcity is a common problem throughout the Southwestern United States. Rainwater Harvesting (RWH), in urban and suburban environments, has potential to conserve existing water resources and reduce flash flooding. Currently, little is understood on how to effectively access this untapped resource. However, participants of a Common Pool Resource (CPR) can achieve resource efficiencies greater than 90 percent. An exhaustive search of published materials was conducted, coupled with communications with the Texas Water Development Board, Edwards Aquifer Authority, San Antonio Water System, and other municipal water utilities. Analysis of CPRs and their design principals reveals that only the Edwards Aquifer Authority and its associated Groundwater Districts constitutes a functioning groundwater CPR in Texas. Of the CPR design principals, only effective monitoring requires engineering. Under the correct circumstances, it would be more appropriate to view RWH as a nested enterprise inside a functioning CPR. This paper explores the possibilities and difficulties of engineering associated with RWH as a nested enterprise in a CPR, specifically RWH in the Edwards Aquifer. A CPR success depends on management rather than engineering. Success of a CPR and its nested enterprises depends on participant behavior. Economic models, based on the mathematics of game theory, help understand how participants of a CPR respond to issues of fairness and communication. A cost effective device can provide effective monitoring of RWH performance. Once monitoring is provided, RWH can be integrated into existing cooperative CPR institutions.