Geohydrology and water resources of alluvial basins in south-central Arizona and parts of adjacent states

Abstract

The Regional Aquifer-System Analysis (RASA) Program was started in 1978 following a congressional mandate to develop quantitative appraisals of the major groundwater systems of the United States. The RASA Program represents a systematic effort to study a number of the Nation's most important aquifer systems, which in aggregate underlie much of the country and which represent an important component of the Nation's total water supply. In general, the boundaries of these studies are identified by the hydrologic extent of each system and accordingly transcend the political subdivisions to which investigations have often arbitrarily been limited in the past. The broad objective for each study is to assemble geologic, hydrologic, and geochemical information, to analyze and develop an understanding of the system, and to develop predictive capabilities that will contribute to the effective management of the system. The use of computer simulation is an important element of the RASA studies, both to develop an understanding of the natural, undisturbed hydrologic system and the changes brought about in it by human activities, and to provide a means of predicting the regional effects of future pumping or other stresses. The final interpretive results of the RASA Program are presented in a series of U.S. Geological Survey Professional Papers that describe the geology, hydrology, and geochemistry of each regional aquifer system. Each study within the RASA Program is assigned a single Professional Paper number, and where the volume of interpretive material warrants, separate topical chapters that consider the principal elements of the investigation may be published. The series of RASA interpretive reports begins with Professional Paper 1400 and thereafter will continue in numerical sequence as the interpretive products of subsequent studies become available.

Location and timing of river-aquifer exchanges in six tributaries to the Columbia River in the Pacific Northwest of the United States

“…For example, streamflow losses were measured at the proximal (upstream) end of unconsolidated basin fill along the base of mountains (e.g., Willamette RK 312 to 299, Methow RK 117 to 106). Although these conditions are similar to those promoting ''mountain-front recharge'' in the southwestern US (Anderson et al, 1992), recharge along the Willamette and Methow Rivers was fluvial rather than from overland flow and the aquifer was likely saturated from the point of recharge (i.e., the riverbed) rather than unsaturated in the case of mountain-front recharge. Fluvial recharge by the Methow River was so high that it lost all of its flow between RK 117 and RK 106 during the autumn or winter in 9 out of 13 years from 1991 to 2003, despite a drainage area of 995 km 2 and perennially flowing tributaries.…”

A simple method for estimating basin-scale groundwater discharge by vegetation in the basin and range province of Arizona using remote sensing information and geographic information systems

“…2;PRISM Group, 2008). There are two distinct precipitation seasons in the study area: a summer season of high-intensity, short duration thunderstorms covering small areas and a winter season of low intensity, long duration frontal systems covering large areas (Anderson et al, 1992). Owing to greater precipitation at higher elevations, aquifer recharge in the area is generally mountain-block and mountain-front recharge with some focused stream channel recharge along washes that drain mountainous areas (Stonestrom et al, 2007).…”

“…1). Tectonic activities associated with the Basin and Range disturbance formed these basins, typified by broad, gently sloping valleys separated by sharply rising mountain ranges (Anderson et al, 1992). Basin fill is composed primarily of erosional material from surrounding mountains.…”

How Might Recharge Change Under Projected Climate Change in the Western U.S.?

“…Groundwater is often relied upon to make up for shortfalls in surface water resources during times of drought (Dettinger & Earman, ). Although there are some local studies for individual basins (Ajami et al, ; Anderson et al, ; Crosbie et al, ; Flint & Flint, ; Serrat‐Capdevila et al, ; Vacarro, 1992), the cumulative effect of climate change on recharge over the western U.S. is not well understood. It is unknown whether overall recharge will increase, decrease, or stay the same in the western U.S. (Dettinger & Earman, ).…”