Streamflow gain/loss in the Republican River Basin, Nebraska, October 1998

Tributaries were followed upstream until the first road crossing where zero flow was encountered. Measurements also included estimates of average wastewater discharge during the period when the flow measurements were made, based upon data obtained from towns having measurable wastewater discharge. For selected streams, points of zero flow upstream of the first zero flow site also were checked.

Stream flow gain or loss for each stream reach was calculated by subtracting the stream flow values measured at the upstream end of the reach and values for contributing tributaries from the downstream value. The data obtained reflected base-flow conditions suitable for estimating stream flow gains and losses for stream reaches between sites. However, due to fluctuations in stream flow on the main stem of the Republican River above Swanson Reservoir during the measurement period, flow measurements on the main stem could not be used for calculating reach gains and losses.

Flows measured on tributaries to the Republican River above Swanson Reservoir were of suitable quality to use for stream flow gain/loss calculations. Flows on Sappa Creek did not reflect base-flow conditions and thus were not suitable for investigating ground-water/surface-water interaction. This digital data set was created by manually splitting the lines from a 1:250,000 hydrography data set (Soenksen and others, 1999) at every stream flow-measurement site.

Each set of stream segments between measurement sites was assigned a unique reach number. This digital data set was created by manually plotting locations of stream flow measurements. These points were used to designate steam-reach segments to calculate gain/loss per river mile.

Reach segments were created by manually splitting the lines from a 1:250,000 hydrography data set (Soenksen and others, 1999) at every location where the streams were measured. Each stream-reach segment between stream flow measurement sites was assigned a unique reach number. All other lines in the hydrography data set without reach numbers were omitted.