S. W. West 1955 <p>Ground-water levels in the Whitney terrace area, after many years of rise owing to downward percolation of water from irrigated land, became nearly stabilized by 1935. &nbsp;Strong seasonal water-level fluctuations of 8 to 10 feet, however, are common in the Boise Valley. &nbsp;In recent years, the Whitney terrace has been changing rapidly from a farming to an urban community. &nbsp;The 3,200-acre area now has about 15,000 inhabitants and the land area is about 35-percent occupied by urban developments. &nbsp;Population trends indicate that urban expansion will continue. &nbsp;</p> <p>Coincident with the change from rural to urban conditions on the Whitney terrace, the patterns of water use were drastically altered. &nbsp;The amount of irrigated land has decreased but the amount of ground-water recharge from irrigation and yard water may have increased. &nbsp;Liquid sewage effluent disposed in the ground also has increased the yearly volume of recharge. &nbsp;The estimated average yearly amount of recharge from all sources now is about 2.4 acre-feet per acre. &nbsp;Full urban development of the area may increase recharge from all sources to about 3.3 acre-feet per acre.</p> <p>Ground-water and drainage problems can be relieved by reducing excessive recharge to the ground-water reservoir. &nbsp;Reduction can be accomplished by economical use of water by individuals, establishment of a water-tight public sewage system to transport all sewage to a central plant outside of the area, and by drainage works. &nbsp;These measures would cause a net decline of ground-water levels in the area. &nbsp;They can be undertaken separately or collectively.</p> application/pdf 10.3133/ofr55192 en U.S. Geological Survey Ground-water and drainage problems in the Whitney terrace area, Boise, Idaho reports