Table 2-1. Regional-Scale Saturated Zone Flow Models Encompassing Yucca Mountain
| Area | Dimension/Model Type/Author (year) | Assumptions | Weaknesses/Effects Not Considered | Strengths/Effects Considered |
| Regional NTS | 2-D Finite Element Waddell (1982) |
Steady-state. Confined aquifer. Isotropic transmissivity. 19 transmissivity zones. 12 fluxes. |
Inaccurate heads at eastern Pahute Mesa | Calibration to minimize head residuals. Good fit to head data. Fluxes computed. Extensive sensitivity analysis on flux, transmissivity, and head. |
| Regional | 2-D Finite Difference Rice (1984) |
Steady-state. Confined aquifer. Potential evapotranspiration and actual evapotranspiration estimates. |
Confined model. Not calibrated. Few transmissivity zones. |
Recharge data included. Recharge sensitivity analysis. |
| Regional and sub-regional | 2-D Finite Difference Ahola and Sagar (1992) |
Initial steady-state. Free surface. Transient climatic changes. Conductivity changes due to volcanic or tectonic activity. Regional hydraulic conductivities and zones modified from Rice (1984). |
Regional model not calibrated (data from previous calibrated models). Scenario recharge not based on detailed climate analysis. |
First transient analysis. Unconfined aquifer (free surface). |
| Great-Basin Regional |
Pseudo 3-D 2-layer Prudic et al. (1993) |
Steady-state. Confined aquifer. 97 km2 (37.5 mi2) grid. Carbonate aquifer only. No over-pumpage. Only large features (lakes, large rivers) modeled. |
Large scale of limited use in Yucca Mountain SZ modeling. | May be used to examine boundary conditions in smaller scale models. |
| Regional | Pseudo-3D 2-layer with middle vertical leakage layer Finite Difference Sinton (1987) |
Steady state. Confined aquifer. Recharge and discharge estimates taken from Waddell (1982) and Czarnecki and Waddell (1984). |
External boundary considered no-flow. Inflow modeled as recharge at external nodes. Calibration does not consider transmissivity, or recharge residuals |
Most residuals less that 15 m (49 ft). |
| Regional | 3-D Finite Difference D’Agnese et al. (1997) |
Steady state. Confined aquifer. Calibration to head and spring flow. 3 transmissivity layers. |
Temporal pump test data not used in inversion. Few transmissivity and recharge zones. No spatial transmissivity geostatistics. |
Use of extensive database (geology, hydrology, recharge, discharge, climate). Calibration to heads and stream flow. Compare conductivity to measured data. |
| Regional | 3-D Finite Difference D’Agnese et al. (1999) |
As above, but future (global-warming) and past (full-glacial) effects considered. | As above. | As above. |