US Geological Survey


Date of this Version



The Cooperative Hydrology Study (COHYST) is a geohydrologic study of surface and groundwater resources in the Platte River Basin of Nebraska upstream from Columbus, Nebraska. Information relating to COHYST and the products produced by it are found at the website . COHYST was started in early 1998 to develop scientifically supportable hydrologic databases, analyses, models, and other information which, when completed, will:

1. Assist Nebraska to meet obligation under a separate three-state Cooperative Agreement (CA). (Governors of Wyoming, Colorado, and Nebraska, and the Secretary of the Interior, 1997)

2. Assist Nebraska's Natural Resources Districts along the Platte River in providing appropriate regulation and management.

3. Provide Nebraskans with a basis to develop policy and procedures related to groundwater and surface water.

4. Help Nebraskans analyze proposed activities of the CA and/or other water management programs in Nebraska.