Agenda - 05-23-1983 - Laserfiche WebLink

Browse Search

, 1 , , 093Memo May 17, 1983 Page 2 Blaha emphasized that the key objectives are to preserve undisturbed land and minimize impervious surfaces. I b) Blaha noted that detention basins received much support during the 1970s, but have since been recognized as causing significant problems, particularly with stream bank erosion, maintenance, and safety and health problems. c) Impoundments are similar to detention basins, but are built to a significantly larger scale and provide longer detention periods. d) Denlpity controls generally refer to larger lot size minimums to prdyide for a smaller proportion of impervious surface on the lot. 1 Blaha described stormwater management programs in Maryland, Florida and Farifax, Vironia. The staff of Maryland passed legislation in June, 1982 requiring local jurisdictions to adopt stormwater management ordinances with the following guidelines that post-development equal to or be lower than the volume ofipre-development runoff generated in a 10-year storm, and that the preferred approaches , in order, are infiltration,flow attenuation, reten- tion and detention. Florida requires a permit for all stormwater discharges directly into a stream and requires the first inch of rain to be infiltrated on the site. Fairfax; Virginia has been a pioneer in stormwater management for water quality purposes. Though the initial preferred approach was detention basins, 1 as a result of problems associated with the basina, the County has rezoned I approximately one-half of their watersheds to five acre lots to achieve the de- sired objectives. Blaha ndted that the location of Orange County, the predominant soil types, , the presence of headwaters, the size of the watersheds and the relatively un- developed ch4racter of the County indicate that stormwater management options are open for the County. In response to a concern regarding ground water contamination[due to infiltration techniques, Blaha noted that given the resi- dential pattern of development,expected pollutants and soil types, this would „ not be a serious problem except in reference to industrial development. Blaha distributed the TICOG Watershed Management -Technica.I'Bulletin #2 . -- and summarize its comments. 1 - 1 Steve Gurley from Wake County reviewed the County's General Development Plan and described the water supply watershed plan category. Three water supply watersheds, including the Falls of the Neuse, Little River and Swift Creek,have this plan designation. The preferred land use is residential development on 40,000 square foot lots. Complimentary neighborhood type commer- cial uses witN no greater than 5000 square feet of floor area located - thoroughfares low density recreational uses and institutional uses are also permitted. I Wake County utilizes a Consolidated Open Space Development Technique which allows 30% of M piece of property to be developed intensely with open space and . - utilities in the remaining 70Z, Other stormwater management techniques being discussed are impervious surface limitations, vegetational buffers and mimimum _ = 1 EMBIMINNEMIllso■•••-- --