Increased urbanization prevents natural infiltration of precipitation into the groundwater and increases the amount of surface runoff into the streams and rivers, resulting in less groundwater recharge and more river flooding. However, urbanization does not have to be as impermeable as we usually design it. There are simple techniques that can be implemented, from city scale to house scale. Such practices include rain gardens, rain barrels, green roofs, swales, permeable pavement, etc. The goal of each of these is to create a disconnect between the increased surface runoff and the river, and thus promote infiltration or evaporation.