Knowledge of the transit losses and water-wave traveltimes in the Neosho River for varying reservoir-release volumes and durations is necessary for proper management of water supply. Two reaches were studied along the Neosho River in east-central Kansas. The upper reach is from Council Grove Lake to John Redmond Reservoir, a distance of 83.0 river miles. The lower reach is from John Redmond Reservoir to Iola, Kansas, a distance of 56.3 river miles. Channel and aquifer characteristics were estimated from available data and used in a streamflow routing model. These estimated characteristics were verified using the model by comparing simulated reservoir releases to observed reservoir releases. The verified model then was used to simulate transit losses (or gains) and traveltimes for selected reservoir release volumes and durations from Council Grove Lake to Iola. Transit losses and traveltimes were investigated for the selected reservoir releases while under a severe drought antecedent streamflow condition (zero base flow) and a less severe drought antecedent streamflow condition (2% drought base flows). The largest total transit loss from Council Grove Lake to Iola occurred during the severe drought antecedent streamflow condition, small reservoir release rates, and long reservoir release durations. The total transit loss included water that was temporarily lost to bank storage. For a severe drought condition, transit losses ranged from 1,100 acre-ft for a release volume of 1,840 acre-ft for a duration of 50 days to 6 ,280 acre-ft for a release volume of 6,280 acre-ft for a duration of 365 days. For a less severe drought condition, transit losses ranged from 860 acre-ft to 3,234 acre-ft for the same release volumes and durations as for the severe drought condition. (Author 's abstract)
