The requirement for sustainable water use is that the city uses only renewable water resources. The city has renewable, surface water rights of 69,000 acre-feet per year. These water rights are titled for consumptive use. Currently, the city returns one half of the supplied water to the river through the wastewater treatment plant. Therefore, the city can divert and use twice the titled water rights for supply, 138,000 acre-feet per year. The city must still rely on ground water for some portion of its water supply. Without a ground water component, the city would need large and more costly treatment facilities to meet seasonal peak demands. However, the amount to be pumped should be limited to the renewable portion of ground water. Renewable ground water is 50,000 acre-feet per year that is replenished by streamflow. To use 88,000 acre-feet of surface water, the city needs water treatment facilities. However, this measure alone can meet the city\u27s increasing demand for only a few decades depending on the growth scenario. The city requires additional measures for long-term supply. The most viable measure is water conservation
