6.2.2.e Drainage Patterns Discussion

Surprise lies largely within the West Salt River Valley sub-basin and in a small portion of the Hassayampa basin. The basins in Arizona are mostly made of unconsolidated basin-filled deposits and consolidated sedimentary. These deposits are sands, silts and gravel which are very permeable. The aquifers here can range in depth from 20 feet near the mountains to 150 feet in the center of the basins. Typically the aquifers in Central Arizona yield considerable groundwater. In the West Salt River Valley sub-basin, groundwater enters as underflow from the Lake Pleasant sub-basin, the northern part of the Hassayampa sub-basin and the Maricopa-Stanfield sub-basin in Pinal County.

Figure 6.2D

Depth to bedrock (in feet) draped over topography. The bulls-eyes are deep basins. Oppenheimer and Sumner (1980)