General effects of drought on water resources of the southwest

The effects of drought are most pronounced on soil moisture, because soil is the prime recipient of the water from precipitation, and upon streamflow, because it is the residual water that is not accepted by or that flows out from the soil and groundwater reservoirs. Studies by statistical correlation of records of natural streamflow and of dendrochronology indicate patterns of regional runoff that reflect precipitation trends in the principal meteorologic regions in the Southwest. By contrast, the effects of drought upon ground water vary with the natural characteristics and degree of utilization of individual aquifers.