Lower South Platte Water Management and Storage Site Study

GEI was retained by the Colorado Water Conservation Board (CWCB) for the completion of a reconnaissance-level study to identify and evaluate surface water storage and management options in the Lower South Platte River Basin.

Identifying potential structural and non-structural water management alternatives along the South Platte River in northeastern Colorado was important to the CWCB so they could address the augmentation needs of junior water users, maintain stream flows to improve waterfowl and riparian habitat, and improve water rights administration through increased flexibility for storing and releasing augmentation water. These objectives would need to be met while maintaining current levels of agricultural production in the Lower Basin.

Significant volumes of water are available to be developed under a junior water right based on a monthly water availability analysis, and the storage alternatives all assume using existing water conveyance canals and ditches to fill the storage.

The study included identifying new surface water storage sites, an analysis of existing surface water storage sites that could be modified or expanded, an evaluation of options for conveyance of water to and from each site, a review of operating plans for existing storage reservoirs and recommendations that could increase water yield associated with these existing reservoirs.

The GEI study team evaluated 22 storage sites through a systematic screening process. Five conventional dam/reservoir projects, the enlargement of Julesburg Reservoir, and the Ovid ring-dike project were found to be the strongest storage options based on cost, permitting, institutional, and other weighted factors considered in the screening process.

The results of this study will help decision makers to evaluate the most effective means of developing additional water management facilities for protecting existing and future water uses in Colorado while meeting water management objectives in the Platte River system.