26
STANLEY N. DAVIS
Fig. 13. Groundwater circulation in fractured carbonate rocks of eastern and
southern Nevada.
underlay most of the valleys. The carbonate rock was found to be relatively
permeable when compared to much of the pyroclastic material in the valley. Furthermore, the hydraulic heads in the valley fill were larger than
the heads in the underlying carbonate rock. These facts suggested that the
carbonate rocks formed an underdrain for the entire region. Extensive
springs in Ash Meadows to the west of the Nevada Test Site were found
to represent the natural discharge area of the underdrain system (Winograd, 1962).
Eakin (1966) has described a much larger area in eastern Nevada. Although not as thoroughly studied as the Nevada Test Site system, Eakin
has assembled hydrologie geochemical and geologic data which suggest
very strongly that a similar, but more complex, underdrainage system operates in a large region from southern Elko County southward to near the
Arizona border. This is a total north-south distance of roughly 400 km.
The groundwater system of eastern Nevada is in a region of thirteen distinct valleys of which seven are topographically closed and six are within
the integrated drainage system of the "White River Wash."
Both the southern Nevada Test Site system and the eastern Nevada system are in areas of minor groundwater pumpage. The problems and eco-
STANLEY N. DAVIS
Fig. 13. Groundwater circulation in fractured carbonate rocks of eastern and
southern Nevada.
underlay most of the valleys. The carbonate rock was found to be relatively
permeable when compared to much of the pyroclastic material in the valley. Furthermore, the hydraulic heads in the valley fill were larger than
the heads in the underlying carbonate rock. These facts suggested that the
carbonate rocks formed an underdrain for the entire region. Extensive
springs in Ash Meadows to the west of the Nevada Test Site were found
to represent the natural discharge area of the underdrain system (Winograd, 1962).
Eakin (1966) has described a much larger area in eastern Nevada. Although not as thoroughly studied as the Nevada Test Site system, Eakin
has assembled hydrologie geochemical and geologic data which suggest
very strongly that a similar, but more complex, underdrainage system operates in a large region from southern Elko County southward to near the
Arizona border. This is a total north-south distance of roughly 400 km.
The groundwater system of eastern Nevada is in a region of thirteen distinct valleys of which seven are topographically closed and six are within
the integrated drainage system of the "White River Wash."
Both the southern Nevada Test Site system and the eastern Nevada system are in areas of minor groundwater pumpage. The problems and eco-