Since planning for droughts must be done in wet cycles, storing surplus surface water behind dams or in aquifers is essential. Underground storage is enhanced by increasing the infiltration of water into the soil, using in-channel and off-channel spreading systems and basins. In-channel spreading is achieved with low dams or weirs that increase the width and depth of streams, or by constructing T- or L-dikes in the streambed to spread the water over the entire width of the bed. Off-channel systems are mostly specially constructed infiltration basins or old gravel pits. Contrary to what may intuitively be expected, shallow basins tend to give higher infiltration rates than deep basins because there is less compaction of clogging layers that accumulate on the bottom due to suspended solids and biological activity. This is demonstrated with a soils engineering analysis and with field data. Artificial recharge can also be important in temporary storage of water, for example, in connection with seasonal changes in the use of sewage effluent for irrigation or in the demand for drinking water. For the latter, such aquifer storage and recovery generally is much less expensive than building water treatment plants with enough peaking capacity or surface storage. Artificial recharge also can play a role in the reuse of wastewater because it provides treatment benefits, gives seasonal storage, and improves the aesthetics of water reuse by breaking up the pipe-to-pipe connection of direct reuse.