FLOOD06380

• County: Statewide
• Community: Adams/Arapahoe/Denver/Broomfield/Douglas/Jeffco
• Basin: Statewide
• Title: Urban Storm Drainage, Criteria Manual Volume 2
• Date: 6/1/2001
• Prepared By: Wright Water Engineers, Inc.
• Floodplain - Doc Type: Educational/Technical/Reference Information

e

e

e

DRAINAGE CRITERIA MANUAL (V. 2)

TABLE OF CONTENTS

Storage

1.0 OVERViEW............... ................................................................................................................ SO-1

2.0 APPLICATION OF DIFFERENT TYPES OF STORAGE ..........................................................SO-3

HYDROLOGIC AND HYDRAULIC DESIGN BASIS..................................................................SO-7
3.1 Procedures for the Sizing of Storage Volumes.............................................................SO-7
3.1.1 Use of Simplified On-Site Detention Sizing Procedures ..................................SO-7
3.1.2 Use of Regional (i.e., Hydrograph Routing) Detention Sizing
Procedure... ..... ...... ......... ..... ..... ...... .... .......... ..... ......... ..... ..... ..... ..... ............ ...... SO-7
3.1.3 Water Quality Capture Volume in Sizing Detention Storage ...........................SO-7
3.2 Sizing of On-Site Detention Facilities............................................................................ SO -8
3.2.1 Maximum Allowable Unit Release Rates for On-Site Facilities .......................SO-8
3.2.2 Empirical Equations for the Sizing of On-Site Detention Storage
Volumes ..... ..... '.." ......... ...... ..... ..... .... ........... ...... .....,.. .......... ..... ..... ...... ...... ...... SO-8
3.2.3 Rational Formula-Based Modified FAA Procedure..........................................SO-9
3.2.4 Multi-Level Control........................ ................................ ................................. SO-11
3.3 Design Storms for Sizing Storage Volumes................................................................SO-11
3.3.1 Water Quality Capture Volume ......................................................................SO-11
3.3.2 Drainage and Flood Control...........................................................................SO-12
3.3.3 Spillway Sizing ........................ ................ ..,................................... ................. SO-12
3.3.4 Retention Facilities............. .... .................................................. ...................... SO-12
3.4 Reservoir Routing of Storm Hydrographs for Sizing of Storage Volumes ..................SO-13
3.4.1 Initial Sizing........................ ....................,...............................................'....... SO-16
3.4.2 Initial Shaping............................................................................... .................. SO-17
3.4.3 Outlet Works Design ......................................................................................SO-17
3.4.3.1 Orifices............................ .............................................................. SO-17

3.4.3.2 Weirs.....................,..... .... ........................................................ ...... SO-18
3.4.4 Preliminary Design ........................... ...... .................. ..... ................................ .SO-20
3.4.5 Final Design.... ................................. ........................ ..............................'....... SO-20

4.0 FINAL DESIGN CONSiDERATIONS..... ................ .........,................................. ........... ............ SO-26

4.1 Storage Volume .................................................................................... ...................... SO-26
4.2 Potential for Multiple Uses ..........................................................................................SO-26
4.3 Geometry of Storage Facilities.................. ........................................... ....................... SO-26
4.4 Embankments and Cut Slopes ...................................................................................SO-27
4.5 Linings................................................................. .................................. .... .................. SO-27
4.6 Inlets.............,............................ ................ .......... ............................................ ............ SO-28
4.7 Outlet Works. ............... ............................. .................... ........................ .... .................. SO-28
4.8 Trash Racks.. .... .......................................,.......... .................. ..... .................... ...... ....... SO-28
4.9 Vegetation ..... ............... ............. .......................................................................... ........ SO-28
4.10 Operation and Maintenance........................................................................................SO-28
4.11 Access........................................................................... .............................................. SO-30
4.12 Geotechnical Considerations ......................................................................................SO-31
4.13 Environmental Permitting and Other Considerations..................................................SO-31

3.0

5.0 CRITERIA FOR DISTRICT MAINTENANCE ELIGIBILITY .....................................................SO-34

6.0

DESIGN EXAMPLES................ ...........................................,.................................................. .SO-35
6.1 Example-Allowable Unit Release Rate and Minimum Storage
Requirement... .... ..... ...... .... ......... ..... ..... ......... ................ ......... ..... .... ...... ......... ....... ....., SO-35
6.2 Example-Rational Method Analysis................... ................................ .......... ............ .SO-35
6.3 Example-Hydrograph Procedure Preliminary Sizing .:..............................................SO-37

CHECKLIST.... ...... ...... .... ..... "'" ..... ........ ...... ..... ..... .... ...... .......... ..... ... ..... ..... ..... .......... ..... ...,.. ..SO-39

7.0

6/2001
Urban Drainage and Flood Control District

TOC-v