The study design for ground water focuses on assessing the water-quality conditions of major aquifers in each study unit with emphasis on the quality of recently recharged ground water associated with present and recent human activities. In contrast to stream-water quality which is highly variable through time, ground-water quality is determined by chemical characteristics that tend to vary more spatially than temporally. Therefore, the general approach to the ground-water assessment focuses on spatial characterization with an emphasis on the chemical characteristics of ground water (Gilliom and others, 1995, p. 26).
In the ALMN Study Unit, ground-water samples were collected by one of two types of data collection study approaches -- a land-use effects survey (termed a Land-Use Study) or a Study-Unit Survey (i.e., reconnaissance survey). Many constituents were measured at the selected wells. For a complete overview of the ground-water study components review the Study-Unit Design Summary Table. The following ground-water study components were developed and completed as part of the ALMN NAWQA Project: