sustainable agriculture groundwater replenishment recharge pits constructed catchments ideal applications groundwater rivers dry periods filtration units reservoirs filtration agricultural land sedimentation tanks storing rainwater rainwater harvesting water purchase dry seasons reservoirs water treatment water irrigation livestock large tanks irrigation stored rainwater direct field irrigation rooftops open fields storage tanks ponds trenches collect rainwater livestock care plantations large farms greenhouses promotes responsible water reliable water supply planting seasons usage allegiance water management remove debris silt