Based on the 1∶50000 regional hydrogeological survey conducted in Dawen River Basin, hydrogeological conditions in the downstream area of Dawen River have been discussed, and water rich characteristics of different types of water bearing rock formations have been summarized. It will provide a hydrogeological basis for the protection of groundwater resources. It is indicated that three types of aquifer groups have been identified in this area, they are porous aquifer group in loosely consolidated clastic rocks, fissurekarst aquifer group in carbonate rocks, and fissure aquifer group in magmatic and metamorphic rocks. The enrichment pattern of groundwater is significantly influenced by rivers. The pore water rich areas are distributed near the upstream interception areas of Pipashan overflow dam and Daicunba, and have long been supplied by lateral seepage of river water. It is the main reason for the formation of rich water areas. Karst water rich areas are distributed in the area between two dams. It is controlled by geological and fault structures, with river water leakage as the main source of recharge. The excavation of sand in the river channel damages the Quaternary water bearing rock formations, and results in changes in regional hydrogeological conditions. The water rich properties of pore water in the areas between the river dams weaken, while the water rich properties of karst water increase. The direct recharge of karst water by river water has led to a significant change in hydrochemical type of the karst water. Hydrochemical type has changed from being predominantly bicarbonatesulfate to predominantly chloride and sulfate.