Publication Summary

This is a study of groundwater inflow and outflow on the Naches and Tieton rivers for a Total Maximum Daily Load (water cleanup plan) temperature analysis. Methods used included seepage runs, a thermal infrared survey, vertical hydraulic gradient measurements, and hyporheic temperature measurements.

Four of six aggregated reaches on the Naches River showed flow gains; one reach showed a flow loss. The total flow gain estimate for the Naches was 200 cfs, and flow loss was 59 cfs. Results for two reaches on the Tieton River indicated flow gains, while one showed a flow loss. The total flow gain estimated on the Tieton River was 42 cfs, and flow loss was 31 cfs.

This revised 2007 version differs from the 2006 version because (1) more information became available for irrigation withdrawals and inputs for the seepage run analysis, (2) one of the flow measurements for the Naches River seepage run was revised, and (3) the number of reaches for the Naches River seepage analysis was reduced from 16 to 6.

This study provides information on groundwater inflow and outflow on the Naches and Tieton rivers for a temperature model needed to complete a Total Maximum Daily Load (water cleanup plan) analysis. Methods used included seepage runs, vertical hydraulic gradient measurements, a thermal infrared survey, and hyporheic temperature measurements. Monitoring activities were conducted in the summer and fall of 2004.

The seepage runs consisted of a one-day flow analysis of the lower 43 miles of the Naches River and six miles of the Tieton River. Each river was divided into stretches of 0.6-12 miles, and flow measurements were taken at the top and bottom of each reach. The Naches River flow reaches were then aggregated into six large reaches based on morphologic characteristics. Four aggregated reaches on the Naches showed flow gains. One of the aggregated reaches showed flow losses. Two reaches on the Tieton River indicated flow gains, while two indicated flow losses. The total flow gain estimated on the Naches River during the seepage run was 200 cfs, and flow loss was 59 cfs. The total flow gain estimated on the Tieton River was 42 cfs, and flow loss was 31 cfs.

Gain/loss results from the more localized methods were generally in agreement with the seepage run results.

The temperature of inflowing groundwater measured by instream piezometers and hyporheic temperature loggers was 9.8-17.7°C in the Naches River and 12.7-13.9°C in the Tieton River. August groundwater/hyporheic temperatures were 1-6°C warmer than October groundwater/ hyporheic temperatures.

Link to EIM data for User Study ID STEB0001