Stormwater Manual - Pima County Flood Control District

More documents

Recommendations

Info

Specific corrective maintenance activities include: • Pond dewatering and removal of accumulated sediments. The frequency will depend on a variety of factors including use of pretreatment BMPs or forebays, contributing drainage area, land use, sediment loading, etc. A good rule of thumb is to remove sediment when 10 to 20 % of the system’s storage volume has been lost. • Structural repairs to inlets, outlets, or discharge structure, including the emergency spillway. • Repairs to the dam, embankment, or slopes to prevent erosion or piping. • Repairs to fences, if applicable. Inspection Inspections are necessary monthly and after large storms to assure proper discharge, monitor accumulations of trash and debris, monitor sediment accumulations in forebays or inlets, determine mowing or vegetation removal needs, and determine health of littoral zone vegetation. Inspections should include the following: • Obstructions of the inlet or outlet devices by trash and debris • Excessive erosion or sedimentation • Cracking or settling of the dam • Low spots in the bottom of an extended detention facility • Deterioration of pipes • Condition of the emergency spillway • Stability of the side-slopes • Up and downstream channel conditions • Signs of vandalism Monitor pond sediment accumulations annually. This can be done by coring, installation of a permanent measuring device such as a “yardstick,” or even by mapping the pond bathymetry in larger ponds. 12.4.4 Responsibility of Lexington-Fayette Urban <strong>County</strong> Government (LFUCG) • Inspect the facility once each year and schedule any appropriate maintenance activities in accordance with the items listed above. • Conduct all maintenance activities except those of commercial property owner listed below. Removal of deposited sediment is envisioned approximately once every five years. 12.4.5 Responsibility of Commercial Property Owner • Conduct all required maintenance. STORMWATER MANUAL 12-8 January 1, 2009 LEXINGTON-FAYETTE CO., KY
12.5 Constructed Wetlands 12.5.1 Description A runoff storage and treatment area constructed in uplands that is vegetated with aquatic macrophyte plants native to the area. These systems attempt to incorporate properties of natural wetlands such as shallow, sheet flow through dense, diverse assemblage of wetland plants that also serve as habitat for microorganisms. 12.5.2 Pollutant Removal Mechanisms • Settling or sedimentation • Adsorption to sediments, vegetation, or detritus • Filtration by plants • Microbial uptake and/or transformations • Uptake by wetland plants or algae • Extended detention • Removal of stormwater pollutants primarily occurs during the relatively long quiescent period between storms 12.5.3 Operation, Maintenance, and Inspection Operation Successful operation depends on good design, construction, and maintenance, especially of the sediment forebays, wetland vegetation, and the discharge structure. Maintenance Activities necessary to maintain the long term functioning of a constructed wetland system include the following: • Grass mowing and removal from side slopes and the embankment • Removal of trees, brush, and animal burrows from the embankment • Vegetative cover stabilization to prevent erosion of side slopes and the embankment • Removal and disposal of trash and debris, especially from inlet or outlet structures • Monitoring and periodic removal of nuisance plant and animal species • Thinning and transplanting of thriving wetland plants as needed to maintain good growth throughout the constructed wetland • Monitoring for mosquitoes • Monitoring and removal of sediment accumulations in forebays or within the constructed wetland Inspection • Inspect quarterly and after large storms to assure proper discharge, monitor accumulations of trash and debris, monitor sediment accumulations in forebays or STORMWATER MANUAL 12-9 January 1, 2009 LEXINGTON-FAYETTE CO., KY
Page 1 and 2:
Stormwater Manual Lexington-Fayette
Page 3 and 4:
1.1 Introduction Chapter 1 gives th
Page 5 and 6:
1.3 Definitions 1.3.1 Public Draina
Page 7 and 8:
• the Division of Engineering det
Page 9 and 10:
• Masterson Station Watershed hyd
Page 11 and 12:
• only one corporation or busines
Page 13 and 14:
1.5 Water Quantity Criteria for New
Page 15 and 16:
TABLE 1- 1 OPTIONS FOR STORMWATER M
Page 17 and 18:
TABLE 1- 2 FLOW CRITERIA FOR STORMW
Page 19 and 20:
contained in Chapter 10. The water
Page 21 and 22:
1.7.4 Water Quality Criteria for Re
Page 23 and 24:
• new development commercial site
Page 27 and 28:
CHAPTER 2 PERMITS
Page 29 and 30:
2.1 Land Disturbance Permit 2.1.1 P
Page 31 and 32:
If the analysis described in the de
Page 33 and 34:
2.3 Kentucky Division of Water KPDE
Page 35 and 36:
2.5 401 and 404 Permits - Kentucky
Page 37 and 38:
3.1 Introduction Watershed studies
Page 39 and 40:
• detailed description of any nat
Page 41 and 42:
3.3 Runoff Models 3.3.1 General The
Page 43 and 44:
3.4 Post-Development Floodplain Ana
Page 45 and 46:
APPENDIX 3-A - SOURCES OF DATA
Page 47 and 48:
National Oceanography and Atmospher
Page 49 and 50:
Pond/Culvert Inventory Data Sheet P
Page 51 and 52:
4.1 Overview 4.1.1 Introduction An
Page 53 and 54:
4.3 Improvement Plans 4.3.1 50 Perc
Page 55 and 56:
• culvert outlet appurtenances an
Page 57 and 58:
4.4 Record Drawings A record drawin
Page 59 and 60:
5.1 Introduction 5.1.1 Purpose The
Page 61 and 62:
5.3 Design Rainfall Event 5.3.1 Sin
Page 63 and 64:
TABLE 5- 2 GREEN-AMPT INFILTRATION
Page 65 and 66:
5.5 Stormwater Management Model (SW
Page 67 and 68:
TABLE 5- 4 MANNINGS N FOR OVERLAND
Page 69 and 70:
APPENDIX 5 A DESIGN STORM DISTRIBUT
Page 71 and 72:
6-HOUR RAINFALL DISTRIBUTIONS Cumul
Page 73 and 74:
100-YEAR - 24-HOUR RAINFALL DISTRIB
Page 75 and 76:
CHAPTER 6 INLETS / STORM SEWERS / M
Page 77 and 78:
6.1.4 Storm Sewers Storm sewers sha
Page 79 and 80:
For d ≥ 1.0’, use the orifice f
Page 81 and 82:
6.4 Construction Specifications All
Page 83 and 84:
7.1 Introduction As used in this ma
Page 85 and 86:
7.2.6 Culvert Skew A culvert shall
Page 87 and 88:
Barrel Area and Shape Barrel area i
Page 89 and 90:
7.5 Bridge Design Procedures Use HE
Page 91 and 92:
CHAPTER 8 CONSTRUCTED CHANNELS
Page 93 and 94:
8.2 Permanent Constructed Channels
Page 95 and 96:
The earth fill materials used to co
Page 97:
8.3 Paved Channels A paved channel
Page 100 and 101:
9.1 Introduction The streams of Fay
Page 102 and 103:
9.2.3 Material Specifications Veget
Page 104 and 105:
TABLE 9- 1 SUGGESTED RIPARIAN SPECI
Page 106 and 107:
9.3 Riparian Buffer Zones 9.3.1 Gen
Page 108 and 109:
9.4 Bioengineering Techniques Bioen
Page 110 and 111:
9.4.3 Root Wad Revetment Root wad r
Page 112 and 113:
Dead stout stakes shall be installe
Page 114 and 115:
Willow tree species are the best fo
Page 116:
9.5.3 Maintenance All structures sh
Page 129 and 130:
10.1 Introduction Non-point source
Page 131 and 132:
TABLE 10- 1 WATER QUALITY DEPTH VER
Page 133 and 134:
Grade the top of the planting soil
Page 135 and 136:
10.4 Infiltration Systems Infiltrat
Page 137 and 138:
Design Criteria To be considered a
Page 139 and 140:
If desired, large infiltration basi
Page 141 and 142:
When the contributing area draining
Page 143 and 144:
Provide sufficient access to the de
Page 145 and 146:
Select underdrain gravel to meet AA
Page 147 and 148:
Compute the total surface area of b
Page 149 and 150:
10.6 Prefabricated Treatment Device
Page 151 and 152:
landscaping plan for the pond and t
Page 153 and 154:
When necessary, compact subgrade su
Page 155 and 156:
After the embankment has been built
Page 157 and 158:
Embankment heights shall not exceed
Page 159 and 160:
10.9 Wet Ponds In this manual, wet
Page 161 and 162:
Q = A (2gH) 0.5 /(1 + K e +K b + K
Page 163 and 164:
Provide a drain with a valve at the
Page 180 and 181:
CHAPTER 11 EROSION AND SEDIMENT CON
Page 182 and 183:
11.1 Purpose This chapter describes
Page 184 and 185:
1. The limitations on coverage set
Page 186 and 187:
11.2.2 Non-Structural Practices Thi
Page 188 and 189:
Figure 11-1. “Seed mats” may be
Page 190 and 191:
peak discharges during construction
Page 192 and 193:
Locations of proposed controls, uti
Page 194 and 195:
11.4 Structural Soil Stabilization
Page 196 and 197:
When using a mulch net, it shall be
Page 198 and 199:
Material Specifications Seed shall
Page 200 and 201:
Material Specifications Soil materi
Page 202 and 203:
11.4.5 Road/Parking Stabilization R
Page 204 and 205:
To reduce maintenance and loss of a
Page 206 and 207:
Effective netting and matting requi
Page 208 and 209:
Maintenance Outlets shall be inspec
Page 210 and 211:
Temporary or permanent seeding and
Page 212 and 213:
A standard flared end section or a
Page 214 and 215:
11.5 Structural Sediment Control BM
Page 216 and 217:
The amount of sediment entering a t
Page 218 and 219: Detention storage shall be provided
Page 220 and 221: The emergency spillway shall have a
Page 222 and 223: PHYSICAL PROPERTY Filtering Efficie
Page 224 and 225: Fasten fabric securely to the stake
Page 226 and 227: SEEDING MIXTURE AND SITE SUITABILIT
Page 228 and 229: Upon removal of the structure, the
Page 230 and 231: 11.5.10 Concrete Washout Pits Concr
Page 232: Inspection of Sediment Controls The
Page 261 and 262: 12.1 Introduction As Fayette County
Page 263 and 264: 12.2 Dry Detention Pond 12.2.1 Desc
Page 265 and 266: 12.3 Dry Extended Detention Pond 12
Page 267: 12.4 Wet Detention Pond 12.4.1 Desc
Page 271 and 272: 12.6 Biofiltration Practices 12.6.1
Page 273 and 274: 12.7 Infiltration Practices 12.7.1
Page 275 and 276: 12.8 Modular Pavement 12.8.1 Descri
Page 277 and 278: 12.10 Prefabricated Treatment Devic
Page 279 and 280: 1Lexington-Fayette Urban County Gov
Page 281 and 282: 2Infiltration Basin Maintenance Ins
Page 283 and 284: 3Infiltration Swale Maintenance Ins
Page 285 and 286: Action to be taken: If any of the a
Page 287 and 288: 6Filtration Facility Maintenance In
Page 289 and 290: Summary of Changes to the LFUCG Sto
Page 291: 11.5.5 Storm Drain Inlet Protection
show all

Stormwater Manual - Pima County Flood Control District

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

Delete template?

Save as template?