Innovative Solutions in the West
Most of the western United States is arid, and the region has faced limited water supplies since settlement. But continued population growth (Colorado's population could exceed 8 million by 2050) is challenging a system already struggling to meet water demands for human consumption, irrigation, industry, and outdoor recreation such as hunting and fishing.
recently suffered catastrophic flooding, the state averages only seven to 16 inches of precipitation annually, and water diversions cause some of its rivers to run dry at times. The South Platte River, for example, a tributary of Nebraska
's legendary Platte River, goes dry in several locations every year. Looking ahead, the Colorado Water Conservation Board (CWCB) has projected that population growth in the South Platte Basin (including Denver) would result in an annual shortage of 29 to 55 billion gallons of water. Faced with this stark reality, the CWCB is exploring and pursuing measures to more efficiently allocate the region's limited water supplies.
One option is to simply transfer water from agriculture to municipal and industrial users. While the agricultural community owns nearly 85 percent of all water rights in Colorado, it contributes only about 1 percent of the state's gross domestic product, and urban users have long coveted that water. According to CWCB projections, agricultural water transfers to municipal users would result in a loss of 22 to 32 percent (180,000 to 267,000 acres) of the state's irrigated agricultural land by 2050.
Transfers of agricultural water to cities could also detrimentally affect waterfowl, fish, and other wildlife. Although water diversions for irrigation during the growing season reduces peak flows in the summer months, flows of many western rivers are enhanced during waterfowl migration and wintering periods by "return flows" from irrigation. This surplus irrigation water returns either directly through runoff or by seeping into groundwater, which feeds many floodplain wetlands and warm-water sloughs, providing important wintering habitat for ducks and other water birds.
In collaboration with many partners, DU has devised an innovative "river augmentation approach" to improve the management of irrigation water for a variety of interests, including waterfowl conservation
This approach involves diverting water owned by water conservancy districts (which represent municipal, industrial, or agricultural partners) to wetland complexes that DU has restored or created. The water in these "recharge wetlands" gradually filters into the underlying aquifer, where the groundwater flows back to the river and is once again available for other uses. Landowners receive valuable "water credits" based on the quantity of water that is returned to the river through this process.
DU's flagship recharge wetland project, on the South Platte River Ranch
, demonstrates how diverse interests can all win through collaboration. The ranch's owner sought to improve his farming and ranching operation, while also enhancing wildlife habitat. DU staff developed a plan that entailed pumping water over 1.5 miles from the South Platte River through a series of moist-soil wetlands. The Lower South Platte Water Conservancy District (LSPWCD), which is responsible for supplying irrigation water in this area, was recruited as a key partner along with the South Platte Water Related Activities Program (SPWRAP), CWCB, and the North American Wetlands Conservation Act
The LSPWCD receives all of the project's marketable water credits to help support its members' irrigation needs. In return for investing capital and paying long-term operation and maintenance costs, the SPWRAP receives water credits from the LSPWCD to address its members' endangered species recovery responsibilities. And finally, DU fulfills its mission
by working with the landowner to provide important migration and wintering habitat for waterfowl.
One of the greatest rewards of this project was saving a family farm. During construction, DU was alerted that eight irrigation wells on a nearby farm were shut down for lack of an approved river augmentation plan. DU was able to work with the LSPWCD to incorporate the farm into the South Platte River Ranch Project and rescue their operation. This system allows the farmer to use the water when it's available and then return it to the river when it's needed by others. The success of DU and its partners along the South Platte River can serve as a model for conservation interests in other regions where water supplies are limited.