Volume 2-05, Chapter 3 - City of Wichita

More documents

Recommendations

Info

Section 3.2.5 - Enhanced Swale 3.2.5.1 General Description Enhanced swales (also referred to as water quality swales) are conveyance channels engineered to capture and treat all or a portion of the WQ v for a drainage area. They differ from a normal drainage channel or swale through the incorporation of specific features that enhance stormwater pollutant removal effectiveness. Enhanced swales are designed with limited longitudinal slopes to force the flow to be slow and shallow, thus allowing for particulates to settle and prevent erosion. Berms and/or check dams installed perpendicular to the flow path promote settling and infiltration. The enhanced swale is designed to include a filter bed of prepared soil that overlays an underdrain system. The swales are sized to allow the WQ v to be filtered or infiltrated through the bottom of the swale. They are dry most of the time and are often a preferred option in residential settings. Figure 3-22 Enhanced Swale Example Enhanced swales are not to be confused with a filter strip or grass channel. Ordinary grass channels are not engineered to provide the same treatment capability as a well-designed enhanced swale with filter media. Filter strips are designed to accommodate overland flow rather than channelized flow. Both of these practices may be used for pretreatment or included in a “treatment train” approach where redundant treatment is provided. 3.2.5.2 Stormwater Management Suitability Enhanced swale systems are designed primarily for stormwater quality and have only a limited ability to provide channel protection or peak flow reduction. Water Quality Enhanced swale systems rely primarily on filtration through an engineered media to provide removal of stormwater contaminants. Page 3 - 70 Volume 2, Technical Guidance
Section 3.2.5 - Enhanced Swale Channel Protection Generally, only the WQ v is treated by an enhanced swale, and another structural control must be used to provide CP v extended detention. However, for some smaller sites, a swale may be designed to capture and detain the full CP v . On-Site Flood Control Enhanced swales must provide flow diversion and/or be designed to safely pass on-site flood flows. Another structural control must be used in conjunction with an enhanced swale system to reduce the post-development peak flow. 3.2.5.3 Pollutant Removal Capabilities The enhanced swale is presumed to be able to remove 90% of the total suspended solids load in typical urban post-development runoff when sized, designed, constructed, and maintained in accordance with the recommended specifications. Undersized or poorly designed swales can reduce TSS removal performance. The following design pollutant removal rates are average pollutant reduction percentages for design purposes derived from sampling data, modeling, and professional judgment. In a situation where a removal rate is not deemed sufficient, additional controls may be put in place at the given site in a series or “treatment train” approach. • Total Suspended Solids – 90% • Total Phosphorus – 50% • Total Nitrogen – 50% • Heavy Metals – 40% • Fecal Coliform – insufficient data For additional information and data on pollutant removal capabilities for enhanced swales, see the National Pollutant Removal Performance Database (2nd Edition) available at www.cwp.org and the National Stormwater Best Management Practices (BMP) Database at www.bmpdatabase.org. 3.2.5.4 Application and Feasibility Criteria Enhanced swales can be used in a variety of development types; however, they are primarily applicable to residential and institutional areas of low to moderate density where the impervious cover in the contributing drainage area is relatively small and along roads and highways. Because of their relatively large land requirement, enhanced swales are generally not used in higher density areas. Volume 2, Technical Guidance Page 3 - 71
Page 1 and 2:
CHAPTER 3 STORMWATER CONTROLS TABLE
Page 3 and 4:
Chapter 3 - Table of Contents 3.2.8
Page 5 and 6:
Chapter 3 - Table of Contents LIST
Page 7 and 8:
Section 3.1 - Stormwater Management
Page 9 and 10:
Page 11 and 12:
Page 13 and 14:
Page 15 and 16:
Page 17 and 18:
Page 19 and 20:
Page 21 and 22:
Page 23 and 24:
Page 25 and 26: Section 3.1 - Stormwater Management
Page 31 and 32: Section 3.2.1 - Stormwater Pond 3.2
Page 33 and 34: Section 3.2.1 - Stormwater Pond Fig
Page 35 and 36: Section 3.2.1 - Stormwater Pond For
Page 37 and 38: Section 3.2.1 - Stormwater Pond •
Page 39 and 40: Section 3.2.1 - Stormwater Pond 1'
Page 45 and 46: Section 3.2.1 - Stormwater Pond 3.2
Page 47 and 48: Section 3.2.1 - Stormwater Pond Ste
Page 53 and 54: Section 3.2.2 - Extended Dry Detent
Page 59 and 60: Section 3.2.3 - Vegetative Filter S
Page 67 and 68: Section 3.2.4 - Grassed Channel 3.2
Page 73 and 74: Section 3.2.4 - Grassed Channel max
Page 75: Section 3.2.5 - Enhanced Swale 3.2.
Page 79 and 80: Section 3.2.5 - Enhanced Swale B. G
Page 81 and 82: Section 3.2.5 - Enhanced Swale High
Page 83 and 84: Section 3.2.5 - Enhanced Swale Side
Page 85 and 86: Section 3.2.5 - Enhanced Swale 3.2.
Page 87 and 88: Section 3.2.6 - Infiltration Trench
Page 99 and 100: Section 3.2.7 - Soakage Trench 3.2.
Page 101 and 102: Section 3.2.7 - Soakage Trench •
Page 103 and 104: Section 3.2.8 - Surface Sand Filter
Page 117 and 118: Section 3.2.9 - Bioretention Areas
Page 127 and 128:
Section 3.2.9 - Bioretention Areas
Page 129 and 130:
Page 131 and 132:
Page 133 and 134:
Section 3.2.10 - Stormwater Wetland
Page 135 and 136:
Page 137 and 138:
Page 139 and 140:
Page 141 and 142:
Page 143 and 144:
Page 145 and 146:
Page 147 and 148:
Page 149 and 150:
Page 151 and 152:
Section 3.3 - Secondary TSS Treatme
Page 153 and 154:
Section 3.3.1 - Proprietary Treatme
Page 155 and 156:
Section 3.3.1 - Proprietary Treatme
Page 157 and 158:
Section 3.3.2 - Gravity (Oil-Water)
Page 159 and 160:
Page 161 and 162:
Page 163 and 164:
Section 3.3.3 - Alum Treatment 3.3.
Page 165 and 166:
Section 3.3.3 - Alum Treatment •
Page 167 and 168:
Section 3.3.4 - Underground Sand Fi
Page 169 and 170:
Page 171 and 172:
Page 173 and 174:
Page 175 and 176:
Page 177 and 178:
Page 179 and 180:
Page 181 and 182:
Section 3.3.5 - Organic Filter 3.3.
Page 183 and 184:
Section 3.3.5 - Organic Filter •
Page 185 and 186:
Section 3.4 - Other Stormwater Mana
Page 187 and 188:
Section 3.4.1 - Conventional Dry De
Page 189 and 190:
Page 191 and 192:
Page 193 and 194:
Section 3.4.2 - Underground Dry Det
Page 195 and 196:
Page 197 and 198:
Page 199 and 200:
Section 3.4.3 - Porous Pavement 3.4
Page 201 and 202:
Section 3.4.3 - Porous Pavement The
Page 203 and 204:
Section 3.4.3 - Porous Pavement com
Page 205 and 206:
Section 3.4.3 - Porous Pavement Fig
Page 207 and 208:
Section 3.4.4 - Modular Porous Pave
Page 209 and 210:
Page 211 and 212:
Page 213 and 214:
Section 3.4.5 - Green Roof 3.4.5 Gr
Page 215 and 216:
Section 3.4.5 - Green Roof Signific
Page 217 and 218:
Section 3.4.5 - Green Roof 3.4.5.3
show all

Volume 2-05, Chapter 3 - City of Wichita

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?