Estimating Spring Discharge to the Snake River, Milner Dam to King Hill, Southern Idaho

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Study Problem

In 1995, the USGS published regression models to quantify discharge from Snake River springs between Milner Dam and King Hill. The models provide estimates of average annual discharge at unmeasurable springs to sum with discharge at measurable springs for an estimate of total annual mean spring discharge to the Snake River between Milner Dam and King Hill. However, changes in land use, water management, and data collection raise questions about whether the regression relationships remain valid. Therefore, it is necessary to update these regression relationships to include data collected in the interim. 

Study Objectives

• Identify all available datasets.
• Collect quarterly synoptic spring discharge measurements.
• Assess the uncertainty associated with using measured stream and spring discharge data to estimate reach losses and gains with a water balance approach.
• Assess the uncertainty associated with statistical approaches.
• Compare the uncertainty between the water balance and statistical approaches and report the findings to IDWR with a recommendation for which approach will be most useful for estimating spring discharge into the future.
• Implement an automated method to estimate spring discharge and integrate new data as they are collected.
• Publish methods, data, and software; present details of uncertainty comparisons between water balance and statistical methods and document the methods and accuracy of the approach used to estimate spring discharge to the Snake River.