Working Together Works: Regional Collaboration in Central Tennessee

Droughts and competing uses for existing water supplies in recent years have dictated creative approaches to water supply planning. This study addresses the water needs through 2060 of four water systems in Maury County which is located in central Tennessee. Recent droughts highlighted the complicated balance of the competing uses including wasteload assimilation, environmental flow for threatened and endangered species, municipal and industrial water supply, irrigation, and recreation. A recently completed water supply plan for a five-county region that included Maury County recommended implementation of five non-structural and structural solutions including:Development of a regional drought management planDevelopment of a water use efficiency programOptimizing release schedules from reservoirsReservoir capacity improvementsRiver intake and pumpback improvementsThis study focuses on the river intake and pumpback alternative and the collaboration needed to develop a technical and financial strategic plan for water supply for the four water systems located in Maury County. The strategic plan employs a creative near-term strategy that can be implemented quickly and at much less cost and impact on rates as well as a long-term approach.Near-Term Strategy – To meet near-term water demands, at much less financial impact to current customers, the strategic plan recommended that Spring Hill enter into a wholesale water purchase agreement with Columbia Power & Water Systems (CPWS). This agreement would provide a firm allocation of capacity for Spring Hill to supplement its existing supply. Based on water demand projections, CPWS has sufficient water supply and treatment capacity to satisfy its own needs as well as the projected supplemental water supply needs for Spring Hill through 2025.Long-Term Strategy – To meet the water demands for the four water systems in Maury County after 2025 and through 2060, the strategic plan recommended construction of a new regional water supply intake and pumping station approximately 15 miles downstream of Spring Hill and Columbia (i.e., indirect potable reuse). The strategic plan also recommended the expansion of Spring Hill’s water supply infrastructure, including expansion of the existing intake on the Duck River, expansion of the existing water treatment plant, and construction of a new raw water pipeline. Expansion of Spring Hill’s existing Duck River intake is linked to the strategic plan’s proposed return of Spring Hill’s treated effluent directly to the Duck River below the water intake, in order to maintain or enhance current flows in the designated critical reach of the Duck River upstream of Columbia.This work highlights the decision-making process used to reach consensus on the many facets of the regional solution and the benefits for the four water systems in Maury County including:Meeting rapidly increasing water demands and addressing the urgent need for additional supply.Using revenues from water sales to Spring Hill to help finance a project to improve regional drought resiliency (river pumpback alternative).Constructing piping connections to enhance Spring Hill’s ability to draw water from CPWS’s water system in an emergency.Employing an agreement that would be viewed favorably by the regulatory agencies and likely facilitate the extension of the existing water withdrawal permits for both Spring Hill and CPWS.Allowing Spring Hill to expand their revenue base prior to assuming debt for the long-term construction program.