Sensitivity Analysis of Hydrological Parameters in Modeling Flow and Transport in the Unsaturated Zone of Yucca Mountain

Zhang, K. ; Wu, Y.S. ; Houseworth, J.E.

United States. Department of Energy. Yucca Mountain Project Office.

关键词: Fractures;    Permeability;    Sensitivity Analysis;    Sensitivity;    Simulation;   

DOI  :  10.2172/893922
RP-ID  :  NA
RP-ID  :  NA
RP-ID  :  893922

美国|英语

来源: UNT Digital Library

【 摘 要 】

The unsaturated fractured volcanic deposits at Yucca Mountain have been intensively investigated as a possible repository site for storing high-level radioactive waste. Field studies at the site have revealed that there exist large variabilities in hydrological parameters over the spatial domain of the mountain. This paper reports on a systematic analysis of hydrological parameters using the site-scale 3-D unsaturated zone (UZ) flow model. The objectives of the sensitivity analyses are to evaluate the effects of uncertainties in hydrologic parameters on modeled UZ flow and contaminant transport results. Sensitivity analyses are carried out relative to fracture and matrix permeability and capillary strength (van Genuchten a), through variation of these parameter values by one standard deviation from the base-case values. The parameter variation results in eight parameter sets. Modeling results for the eight UZ flow sensitivity cases have been compared with field observed data and simulation results from the base-case model. The effects of parameter uncertainties on the flow fields are discussed and evaluated through comparison of results for flow and transport. In general, this study shows that uncertainties in matrix parameters cause larger uncertainty in simulated moisture flux than corresponding uncertainties in fracture properties for unsaturated flow through heterogeneous fractured rock.