The Republican River Basin is located in the northeast corner of the state of Colorado, and extends into the Southwest corner of Nebraska and the Northwest corner of Kansas. This basin consists either entirely or partially of Logan, Sedgwick, Phillips, Washington, Yuma, Kit Carson, and Lincoln counties in Colorado. The surface water sources in the basin are the North and South forks of the Republican River, the Arikaree River, and Beaver Creek. Groundwater in the basin is located mainly in the Ogallala Aquifer. With few large towns and an economy that is predominantly agricultural, irrigation is an important facet in the basin.

It is important to note that only 31 percent of the Republican River Basin is actually located in Colorado, this is about 7,760 square miles. The rest of the basin extends into Nebraska and Kansas. Because of this, an interstate agreement exists to manage the waters of the different streams in the basin between the three states. This agreement is known as the Republican River Compact, which was passed in 1942, and divides the surface waters of the Republican River between the three states. Each state receives a certain allocation of water for each stream, which is dependent upon the amount available in a given year. Colorado was allocated 54,100 acre feet per year, which was divided by each stream. The North Fork of the Republican River was allocated 10,000 acre feet, the South Fork of the Republican River was allocated 25,400, the Arikaree River was allocated 15,400, and Beaver Creek was allocated 3,300 acre feet. The rest of the water was distributed between Nebraska and Kansas.

Irrigation in the basin is done in a number of ways, but the primary method of irrigation is through sprinkler systems, usually center pivot systems. There are around 550,000 irrigated acres in the basin. Much of the water used for irrigation is groundwater, with roughly 4,000 high-capacity wells in use. The primary crops that these irrigation resources are used for in the basin are corn, hay (alfalfa, oat, and grass), sugarbeets, wheat, and sunflowers, among others. Groundwater in the basin is considered Designated Ground Water and is under the jurisdiction of the Ground Water Commission. Surface water in the Republican Basin is not used as much for irrigation, and is overseen by the Division Engineer of Water Division One in the Colorado Division of Water Resources.

Looking to the future, water users in the Republican River Basin are working to use more surface water and less groundwater in order to preserve the Ogallala Aquifer. The Republican River Water Conservation District (RRWCD) is making great efforts to protect the health of the rivers and aquifer within the Republican River Basin. One of the many solutions they are working on is the obtaining of federal funding in order to offer financial incentives for some water users to voluntarily retire irrigation water rights. This will help to reduce consumptive use effects on streamflow. They are also purchasing surface water rights to enhance virgin water supplies to the streams in the basin, and are working on getting water users to purchase and use surface water rights and retire high capacity wells in order to preserve the Ogallala Aquifer. With all this, the RRWCD and water users in the Republican River Basin hope to preserve the important resources in their basin along with the important agriculture related economy and culture that is central to the basin.

Written by Peyton Valentine