Unified Development Ordinance, 4th supplement, September 2017

Part 10A: Unified Development Ordinance City of Raleigh, North Carolina 9 – 35 Effective Date: September 01, 2013 Supp. No. 4 c. The velocity specified according to the following for a discharge point into a vegetated receiving watercourse. Group No. Vegetation Depth of Flow (feet) Maximum Permissible Velocity* (F.P.S.) 1 Bermudagrass t1 4  u1 6  2 Tall fescue t1 3  Reed canarygrass Kentucky bluegrass u1 6  3 Grass and legumes, mixed t1 3  Weeping lovegrass u1 4  4 Lespedeza, sericea t1 2.5  Red fescue, Red top u1 2.5  5 Annuals:** Annual lespedeza (KOBE) t1 2.5  Sundangrass Small grain (rye, oats, barley): Ryegrass u1 2.5  *Do not use on channel slopes steeper than 10%, except for side slopes. **Annuals: use as temporary protection until permanent cover established. 3. General Velocity Standard Any area of a land-disturbing activity or receiving watercourses subject to stormwater runoff velocities in excess of those specified in Sec. 9.4.4.G.2. above from accelerated erosion by provision of an erosion-resistant lining of vegetation in accordance with Sec. 9.4.4.G.2.c. above provided, armored, paved or otherwise nonvegetative watercourse lining shall be provided anywhere the velocity in the receiving watercourse exceeds Sec. 9.4.4.G.2.c. and the prior development velocity by 10%. 4. Critical Soils When the following soils (as defined and described in the soil survey ofWake County North Carolina Soil Conservation Service, United States Department of Agricultural, November, 1970) which are especially vulnerable to erosion from stormwater discharge from land-disturbing activities, occur between a point of stormwater discharge and the next confluence of concentrated stormwater runoff, such areas, on- or off-site shall be protected from accelerated erosion by diverting the stormwater discharge from those soil surfaces. The application of this section may not prevent discharge of stormwater from a land-disturbing activity site. Diversion may include the provision of piped, paved or armored storm drainage facilities: a. Applying sandy loam, 10% to 15% slopes (ApP); b. Cecil sandy loam, 10% to 15% slopes (CeD); c. Cecil sandy loam, 15% to 45% slopes (CeF); d. Creedmore sandy loam, 10% to 20% slopes (CrE); e. Enon fine sandy loam, 10% to 15% slopes (EnD2); f. Georgeville silt loam, 10% to 15% slopes (GeD2); g. Granville sandy loam, 10% to 15% slopes (GrD); h. Helena sandy loam, 10% to 15% slopes (HeD); i. Herndon silt loam, 10% to 25% slopes (HrD2); j. Herndon silt loam, 15% to 25% slopes (HrE); k. Lloyd loam, 10% to 15% slopes (LdD2); l. Louisburg loamy sand, 10% to 15% slopes (LoD); m. Made land, (Ma) greater than 4% slopes under actual field conditions; n. Madison sandy loam, 10% to 15% slopes (MdD2); o. Madison sandy loam, 15% to 25% slopes (MdE2); p. Mayodon sandy loam, 10% to 15% slopes (MfD2); q. Mayodan sandy loam, 15% to 25% slopes (MfE); r. Mayodan silt loam, 10% to 15% slopes (MyD); s. Pinkston sandy loam, 10% to 45% slopes (PkF); t. Wake, 10% to 25% slopes (WkE); u. Wedowee sandy loam, 10% to 15% slopes (WmD2); v. Wedowee sandy loam, 15% to 25% slopes (WmE); w. White Store sandy loam, 10% to 20% slopes (WsE); Article 9.4. Erosion & Sedimentation Control | CHAPTER 9. ​NATURAL RESOURCE PROTECTION Sec. 9.4.5. Maintenance