Dams, weirs, barrages, and check dams are common hydraulic structures used to store or divert water. Dams are constructed across rivers to impound water and form reservoirs. The main types of dams include gravity dams, earth dams, rockfill dams, arch dams, and buttress dams. Weirs are barriers that alter river flows and can be used to divert water into canals. Barrages are low-head dams that consist of gates to control water levels for irrigation. Check dams are small temporary or permanent dams built across drainage ditches to settle sediments, pollutants, and recharge groundwater.