Retention basins are among the most frequently implemented storm water management systems. They are used to collect surface runoff and to improve water quality by natural processes such as sedimentation, decomposition, solar disinfection and soil filtration. In comparison to dry ponds (which hold runoff for a limited period of time and then release the stored water at once), retention basins constantly keep standing water allow for the development of an ecosystem. This allows settled particles to be treated biologically (GDSDS 2005). Water from retention ponds can be reused for groundwater recharge, irrigation or any other purpose, after further treatment if required. As a natural system, retention basins do not require energy or high-tech appliances. Primary implementation costs of retention basins are high and constant maintenance is inevitable, as otherwise pollutant export and erosion can occur (UNHSC 2010).