Stormwater Manual - Pima County Flood Control District

More documents

Recommendations

Info

• Calculate the stage-discharge curve for each structure. • Using the 2-foot contour lines and field information, calculate a stage-area-storage relationship for each structure in the model. Include storage below the permanent pools. The stage-area information will allow the model to account for evaporation during continuous simulation. • Combine the stage-discharge curve with the stage-area-storage curve to make one table for input into the model. 3.3.5 Error Analysis When all the data is entered, run the model and check for errors in the run. Look for mass balance problems, model connectivity, correct data input, and proper model execution. 3.3.6 Calibration The model should be calibrated against historic stream flow data if available. STORMWATER MANUAL 3-6 January 1, 2009 LEXINGTON-FAYETTE CO., KY.
3.4 Post-Development Floodplain Analysis 3.4.1 General Once the runoff model is complete, post-development floodplains shall be determined with the United States Army Corps of Engineers’ HEC-RAS computer program. This program will also provide results to indicate roadway and structure flooding. The design storm for floodplain analysis is contained in Chapter 5. This portion of the chapter details how to build the HEC-RAS input file for a watershed study. 3.4.2 Post-Development Floodplain Definition The post-development floodplain shall be determined for streams shown as waters on Fayette County GIS waters coverage. The post-development watershed condition shall be based on future land use. 3.4.3 Cross-Sections HEC-RAS determines floodplains based on cross-section data provided by the user. The following methodology shall be employed when developing cross-sections. • Starting at the most downstream end of the study area, locate a cross-section at least every 200 feet until the upstream end of the study area is reached. • Orient the cross section so that it is perpendicular to the contour lines. • Using a 2’ contour map, determine stations and elevations along each cross-section. • Determine the station along the left side and the station along the right side of each cross-section that corresponds to the top of bank. • Determine the downstream reach length from each cross-section to the preceding cross-section along the left bank, centerline, and right bank. The data outlined above are required for each cross-section. If a cross-section happens to fall where a tributary intersects the channel, then employ one of the following two options. • Delete the tributary-impacted cross-section from the analysis. • Copy the stations and elevations from the downstream cross-section to the tributaryimpacted cross-section, but increase all the elevations along the tributary-impacted cross-section by the difference in elevation of the centerline of the two cross-sections. If tributaries are to be modeled, treat them similarly to the main stream by working from downstream to upstream and spacing cross-sections at 200’ intervals. 3.4.4 Roughness Values and Coefficients Working from downstream to upstream, specify the following roughness values and coefficients: • left bank = Manning’s n from Chapter 8 STORMWATER MANUAL 3-7 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: 3.3 Runoff Models 3.3.1 General The
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 and 268:
12.4 Wet Detention Pond 12.4.1 Desc
Page 269 and 270:
12.5 Constructed Wetlands 12.5.1 De
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

Create successful ePaper yourself

Delete template?

Save as template?