Harvesting rainwater from storm water drains can be a good way of augmenting groundwater as well as preventing #looding . A reacharge well can be either sunk inside the drain or the water can be diverted from the drain into a reacharge well using a check dam. A precast screen filter and a check dam will reduce silting . The water then can be drained into a reacharge well . Here is an example. This design is quite complicated particularly for large catchments. The run off must be studied from the catchment and recharge wells must start upstream to ensure minimum silting and minimum pressure.