| The San Pedro Riparian National Conservation Area was designated by Congress in 1988 to preserve and enhance riparian resources of the perennial reach of the San Pedro River. The perennial flow is due to geological restrictions forcing groundwater to discharge to the stream. The Sierra Vista area lies above this perennial reach and fully depends on groundwater for its water needs. Consequent excessive pumping has resulted in a regional cone of depression and capture of streamflow water by groundwater wells. As a result, the streamflow has diminished by 50 to 66 percent, compared to pre-development conditions. In addition, the groundwater table within the floodplain alluvium has declined below the root zones of native species and is affecting the health of the riparian ecosystem. Studies have confirmed that continued groundwater overdraft in the area constitutes a long-term threat to the maintenance of the perennial flow and its riparian ecosystem. The effects now being felt by the river are the consequences of pumping years ago, because transit times in the regional aquifer are slow, averaging 23 feet per year.;This study uses an institutional analysis and design framework to identify water and natural resources problems in the area, analyze the existing institutions and attribute problems to institutional deficiencies, and design three institutional alternatives to resolve these problems. The four problems identified in the area are depletion, externality, underinvestment, and maldistribution. The first alternative, which requires the least institutional change, is modeled after a newly-proposed Watershed Management Initiative and includes designating the area as Irrigation Non-expansion Area. The second alternative is a regulatory approach based upon establishing an Active Management Area similar to the Santa Cruz AMA. The third is a market approach based on sweeping statutory changes to recognize the hydraulic connection between ground and surface water to and enable the adoption of a conjunctive management strategy to protect the perennial flow and the sustained groundwater yield in the area. Only the conjunctive management strategy offers a long term solution to the area's problems. It is consistent with protecting public values in water and produces the maximum net benefits to all concerned. |
