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 depthduration-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.