There are certain ways of building swales[0] in an urban environment that can help absorb or slow the leeching of nasty chemicals in runoff into groundwater or

There are certain ways of building swales[0] in an urban environment that can help absorb or slow the leeching of nasty chemicals in runoff into groundwater or communities downstream. [0]http://nwrm.eu/measure/swales http://nwrm.eu/measure/swales