The Gila River drainage from Texas Hill to Dome and the western Mexican drainage areas include about 4,700 square miles in southwestern Arizona. The main water-bearing unit is the alluvium along the Gila River and its tributaries and in the valleys that separate the mountains. Most of the ground-water development has taken place in the Wellton-Mohawk area in the northern part of the Gila River drainage from Texas Hill to Dome area. The use of imported Colorado River water for irrigation caused the water levels to rise, and in the early 1970 's the water levels were within 6 feet of the land surface in most of the area. Since 1961, a network of about 70 wells has been pumping about 200,000 acre-feet of ground water annually for drainage of the waterlogged land in the area. The ground water in the Wellton-Mohawk area is of unsuitable chemical quality for most uses. Information shown on the maps includes depth to water , well depth, altitude of the water level, irrigated area, and specific conductance and Fluoride concentration in the water, A table of historical pumpage also is included. Scale 1:125.000. (Kosco-USGS)