FIGURE 2-1 The five major technical components of MUS systems and some major design criteria.

water is required for all systems, but selection of the source is tied to the end use (particularly with respect to whether that end use is to be potable or not), as are the treatment and management during recharge, storage, and recovery. Major factors that impact the selection of recharge methods include aquifer type, land availability, and proximity to the water source.

These and other factors are described in the sections that follow.

A variety of source waters may be used for underground storage, such as surface water, groundwater, stormwater, treated effluent, and (rarely) produced water. Waters from difference sources may have very different water quality characteristics. The water source used for recharge depends on availability, quality, duration, and reliability, as well as regulatory constraints.

When considering the end use of the water, a suitable water quality source must be selected. However, variations in source water quality and quantity may be mitigated during storage provided adequate storage time and capacity are available. Water quality improvements may occur during pretreatment prior to recharge, during storage, and during posttreatment prior to use. Ideally, the selection of source waters will minimize pre- and posttreatment requirements since these increase overall system cost. Pretreatment may be required to maintain infiltration rates, prevent negative interactions with aquifer materials, and prevent degradation of existing groundwater quality. Pretreatment requirements for recharge basins may be as simple as a stilling basin to remove heavy loads of solids prior to application. Stormwaters and surface waters are typically applied to recharge basins without pretreatment.

High quality source waters such as treated drinking water may suffer from