Agenda - 06-04-1981 - Laserfiche WebLink

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r2 ..,,, hazard potential. The floodway is that area within the stream bunks and adjacent to it required in order to discharge the 100-year flood , - without raising the water surface elevation more than one foot above : be flood level at any point. It is cruc3a1 that the floodway be kept free of obstacles so that this fUnction will not be disrupted. The floodway fringe is the area bordering the floodway which will be inundated during a flood and which serves to hold the floodwaters until it can be carried away in the floodway channel. In addition to the 100-year flood prone area, consideration is also given to the 500-year flood prone area, the area of land susceptible to inundation duzaIng a storm which would occur on the average once every 500 years. The relative probability of these two storm events suggests fewer constraints and, therefore, minimal land use regu- lations in the 500-year flood prone area as opposed to the 100-year flood prone area. The U.S. Army Corps of Engineers prepared maps at a scale of 1" = 1000' for Orange County showing the floodway, the 100-year floodway fringe and the 500-year floodway fringe for all streams draining more than one square mile of watershed. Orange County applied and was admitted to the Flood Insurance Program, and has consequently adopted a Flood Prevention Ordinance. This ordinance constitutes a major regulatory tool affect- ing the use of lands constrained by flood hazards. Soil Conditions ... The interaction of different rock types, local topography, temperature 1 changes, rain, flora and fauna has produced soils which reflect the geological and dramatic Conditions of Orange County. Soils on the County range from well drained, gently sloping uplands to steeply sloped, shallow to bedrock soils, to flat soils subject to flooding along , ' streams. Perhaps no other natural environmental factor has as much influence on land use and land development as soil conditions. Regardless of the particular land use, soils are the most important factor determining the suitability of the land for that use. Soil characteristics such as depth to bedrock, permeability, shrink-swell potential, erodibility and drainage are important factors influencing land use soils present constraints to development ranging from slight limitations to severe limitations. In general, the costs of site preparation and construction will increase as the severity of soil limitations in an area increases. The Soil Conservation Service (SCS) completed a soil survey of Orange County in 1976. Each soil type in Orange County has been described in terms of these characteristics and their potential use and management requirements. The Orange County Planning Department in conjunction with Mr. Robert Kirby, an SCS scientist, combined the 38 soil types identi- fied in the soil survey into ten suitability categories based on simi- lar characteristics as described in the report, A Pl- : Guide to the Orange County, North Carolina This allows the general public to 'mow- in a broad manner what types of development are suitable for certain uses, including septic tanks, foun- dations, roads and prime agricultural land. The soil suitability classi- fication system identifies the constraints posed by the various categories: