Accounting for Water Supply and Uses in the Republican River Basin

The Republican River Basin lies within Nebraska, Colorado, and Kansas. The basin is subject to the 1943 Republican River Compact, an agreement which allocates the annual water supply between the states. The water supply is allocated amongst the Republican River mainstem and its 12 subbasins according to state-specific allocation percentages.  Determining the annual water supply and subsequent allocations relies upon calculating various components of the hydrologic cycle, including stream flows, surface water consumption, and groundwater depletions with the use of a groundwater model developed by the three states. This discussion will focus on the different data components used in this process and how the data are used to quantify the annual water supply and allocation volumes.