The City of Hilliard Sustainability Plan

Hilliard Sustainability Planparticular months of high usage is unavailable but should be incorporatedin future calculations. A good goal would be to reduce residential water usageby 5 to 10%. This will account for a yearly reduction of 38,780.08 to 77,560.16 CCF of water. See EWR Appendix Calculation Sheet 3.Percent pervious surfaceBackgroundImpervious surfaces are simply ground covers that water cannot penetrate.36 According to Geographical Information Systems (GIS) data provided» City of Hilliard (2012). GIS DATA; Impervious Surface.City of Hilliard Ohioby the City, there are approximately2,666 total acres of impervioussurfaces present within Hilliard. 37This accounts for 31% of the 8,545» City of Hilliard (2012). GIS DATA; Impervious Surface.City of Hilliard Ohioacres that makes up the city. 38 This classification includes most asphalt,most types of concrete, building rooftops, and highly compacted soils.Impervious surfaces have been shown to increase the amount of surfacerunoff generated in an area. This runoff causes excessive amounts of waterto discharge into streams, reduces available groundwater resources, andincreases rates of erosion. 39 The amount of impervious surfaces hasalso been shown to have a correlation to non-point source pollutionin a watershed. 40 This relationship means that high levels of waterpollutants such as sediments, salt, heavy metals, pesticides, acids,and nutrients wash off yards, parking lots, and other imperviousareas and enter the watershed. 41 The following chart and map showthe amount of pervious and impervious land cover in Hilliard.MeasureOne measure of the amount of impervious surfaces in an area is avariation of what is known as a coefficient method. It involves determininga set percentage of impervious area by specific variables. Forexample, the rational runoff coefficient method sets basic parametersper standardized land use. 42 This measure is permitted for usein assessing stormwater values in the City of Columbus, 43 but it hasbeen criticized for its inaccuracy. The standard coefficient methodfor calculating the impervious surfaces in an area may fail to measureroadways. 44However, using GIS software to make more accurate measurementsof the percentage of impervious surfaces in an area may provide asuitable alternative. 45 This has been done in part by the city of Hilliard,but the data did not incorporate roadways, driveways, heavilycompacted soils, and many parking lots. 46 Roadways alone accountfor approximately 1,220 acres of land in Hilliard. 47 This figure wascreated using ESRI Arc GIS spatial data processing and, though itgives a picture of the amount of impervious surfaces, is in no waya completely accurate figure. Roadways as well as parking lots anddriveways will need to be made into polygons and incorporatedinto the current dataset that has been created.ECON. EXECUTIVEENERGY DEV. &SOCIAL SUMMARY WASTE EQ.REDUCTION15