The sand and gravel layers of these ancient channels provide good paths of infiltration and ideal storage space for groundwater. We should make thorough use of this large capacity. Most of this capacity is in alluvial fans, where the paths of infiltration are also best. The river channel belts have the next best conditions. Under present circumstances, the underground storage capacity of the deltas is without practical significance for storing water.
Capacity is less in East Route irrigation districts and infiltration conditions are more deficient.
Wei Yongchun and Wu Jun. 1979, The Artificial Groundwarer Recharge and Underground Reservoirs. Water Conservancy and Electric Power Press.