Channel Infiltration in Solitario Canyon, Yucca Mountain, Nevada

It has been hypothesized that the Solitario Canyon watershed, just west of Yucca Mountain, Nev., could provide a zone of focused ground-water recharge through its ephemeral-stream channels that might be an important factor in the performance of the potential repository for high-level radioactive waste. To examine this possibility, the KINEROS2 rainfall-runoff model was used to estimate the infiltration from surface runoff in each of 79 channel elements using a 100-year simulated rainfall sequence and two sets of saturated hydraulic conductivity KS values. The annual average estimated infiltration ranged from 0.18 to 0.57 mm/year (expressed as depth over the entire 10.7 km 2 watershed). Evaporation and transpiration by vegetation near the channels were neglected, therefore these quantities of channel infiltration are not assumed to be ground-water recharge. The simulated rainfall intensities compared favorably with depth-duration-frequency curves for nearby stations. The simulated 100-year peak discharge rates for Solitario Canyon and for four subwatersheds exceeded the regionally estimated 100-year rates for the lowest values of KS and were slightly below those rates for the higher values of KS , suggesting the true value of peak discharge (and channel infiltration from surface runoff) is bounded by those obtained for the 100-year simulations.