HomeMy WebLinkAbout8156RESOLUTION NO. 8156
A RESOLUTION ADOPTING AND APPROVING STORM
DRAINAGE DESIGN CRITERIA AND DRAINAGE POLICIES
FOR THE CITY OF PUEBLO DATED JUNE 9, 1997 PREPARED
AND PUBLISHED BY THE CITY OF PUEBLO DEPARTMENT
OF PUBLIC WORKS, 211 EAST "D" STREET, PUEBLO,
COLORADO
BE IT RESOLVED BY THE CITY COUNCIL OF PUEBLO, COLORADO, that:
SECTION 1
Pursuant to and in furtherance of sections 4- 2 -2(8), 12- 4 -2(7), 12 -4 -5, 12- 4- 6(B)(3)(b) and
12- 4- 7(J)(5)(c) of the 1971 Code of Ordinances of the City of Pueblo, as amended, and upon
recommendation by the City Engineer, the Council does hereby adopt and approve as minimum
stormwater drainage standards the Storm Drainage Design Criteria and Drainage Policies for City
of Pueblo, Colorado, published June 9, 1997 by the Department of Public Works, 211 East "D"
Street, Pueblo, Colorado, a true copy of which is attached hereto and made a part hereof by reference
(hereinafter referred to as the "Drainage Criteria "). The Council declares that the design and
construction of storm drainage facilities within the City for all subdivisions (and resubdivisions)
approved by the City Council after date of approval of this Resolution shall be performed and
installed in conformance with said Drainage Criteria and all other provisions of Title 12 of the 1971
Code of Ordinances, as amended.
SECTION 2
Except as modified by this Resolution, all minimum storm drainage design standards
heretofore adopted shall remain in full force and effect and be applicable to all subdivisions
approved prior to the date of approval of this Resolution.
SECTION 3
After adoption of this Resolution, a true copy of the Drainage Criteria shall be maintained
on file in the office of the City Clerk for public inspection. Copies of the Drainage Criteria shall be
made available through the City's Department of Public Works for purchase by the public at a
moderate price.
in
ATTEST:
City Cler
INTRODUCED: June 9 , 1997
John Verna
Councilperson
APPROVED:
President Of the City Council
-2-
STORM DRAINAGE DESIGN CRITERIA
FOR
THE CITY OF PUEBLO, COLORADO
EXECUTIVE SUMMARY
DRAINAGE POLICIES
2.2 The Policy of the City of Pueblo is to pursue an approach to drainage planning and design
which will consider regional drainage issues and promote the orderly growth of the City.
2.3 The Policy of the City of Pueblo is to require that drainage systems be designed with the
dual purpose of:
a) Conveying runoff from the 100 -year design storm while minimizing health and
safety hazards, property damage, and disruption to emergency services.
b) Conveying runoff from the 5 -year design storm (25 -year design storm in the Central
Business District (CBD)) while minimizing inconvenience to people and traffic.
2.4 The Policy of the City of Pueblo is to restrict development from within the 100 -year
floodplain of a natural drainage channel, or from within an approved erosion buffer zone
for channels with high erosion potential, whichever is greater, and to require that all
provisions of Chapter 9, Title XVII of the Code of Ordinances concerning Flood Damage
Prevention, be followed.
2.5 The Policy of the City of Pueblo is to require that adequate measures be implemented to
minimize soil erosion caused by development.
2.6 The Policy of the City of Pueblo is to restrict the rate of stormwater runoff from
developed land to approximately the rate of runoff from the land in its historic or native
condition.
2.7 The Policy of the City of Pueblo is to require that all stormwater impoundment structures
be designed to meet the requirements of Article 87 of Title 37, Colorado Revised Statutes,
and regulations promulgated thereunder when applicable, and to prohibit development
from within hazardous areas created by the impoundment structure.
2.8 The Policy of the City of Pueblo is to restrict the use of irrigation ditches and canals as
outfalls for drainage systems without the written, irrevocable consent of the owner, and
unless such use is shown to be without hazard by an engineering analysis. In the case of
an abandoned ditch or canal, provisions shall be made for ditch perpetuation prior to being
selected for use as an outfall or conveyance for drainage.
2.9 The Policy of the City of Pueblo is to prohibit development from within ponding areas of
roadway or railroad culverts due to the 100 -year design storm.
2.10 The Policy of the City of Pueblo is to require that adequate measures be taken to insure
that development will not exacerbate existing drainage problems.
2.11 The Policy of the City of Pueblo is to require that adequate measures be taken to prevent
uncontrolled cross lot drainage.
2.12 The Policy of the City of Pueblo is to require that drainage facilities be designed to
minimize maintenance costs and that adequate access be provided for maintenance
equipment. Where portions of the drainage system are on private property, adequate
provisions shall be made for the long term maintenance and operation of the facilities.
2.13 The Policy of the City of Pueblo is to prohibit the discharge of any toxic or hazardous
substances into the storm water system which may cause the municipal discharge to
violate any water quality standard.
DESIGN CRITERIA
Design Storm Frequency
The present criteria requires that drainage facilities in residential zones be designed for the 5 -year
storm and those in commercial and industrial zones be designed for the 25 -year storm.
The new criteria requires that drainage facilities in all zones be designed for the 5 -year storm,
except in the Central Business District, and those be designed for the 25 -year storm. The new
criteria also requires that the effects of the 100 -year storm be considered, and that runoff from
this storm be contained within the R.O.W. or dedicated drainage easements.
Streets
The present criteria requires that the depth of flow in the street due to the 5 -year storm be not
greater than the curb height and that a minimum of 12 feet of driving lane be left open for traffic
on residential streets, and 14 feet on collector and arterial streets.
The new criteria has the dame depth requirements, and reduces the minimum open driving lane to
10 feet on both residential and collector streets but increases it to two 10 feet lanes on arterial
streets.
Floodplains and other Areas subject to Inundation
The new criteria requires that the Consulting Engineer identify and delineate on the subdivision
plat, areas that are subject to flooding, including:
a) The floodplain of natural channels;
b) The limits of ponding for culverts; and
c) The limits of ponding for detention ponds and the path of emergency overflows
The present criteria does not adequately address this concern.
Stormwater Detention Facilities
Stormwater detention is a drainage concept that is not covered in the present drainage criteria, but
which is widely used throughout the country to manage increased runoff due to development.
Although this type of drainage facility requires dedicated land, it can significantly reduce the cost
of downstream improvements and right of way acquisition necessary to mitigate the impacts of
new development.
The new criteria provides design guidelines for stormwater detention facilities.
Cross Lot Drainage
The Public Works Department receives numerous complaints each year from residential property
owners over issues concerning uncontrolled cross lot drainage. The present drainage criteria does
not address this issue.
Under the new criteria, the developer will be required to provide grading plans that show
individual lot drainage patterns. These plans will be referred to at the time of building permit, and
the builder will be required to provide site plans that conform to the approved grading plan.
Erosion Control
The present criteria does not adequately address erosion control issues in new development.
The new criteria requires the consulting engineer to provide an erosion control plan with specific
information on erosion control practices to be employed during construction of the development.
Maintenance
The maintenance of drainage facilities is critical to their proper functioning during times of heavy
rainfall. The present criteria does not adequately address maintenance issues.
The new criteria provides the framework for maintenance agreements, some of which may involve
the City, for the perpetual maintenance of drainage facilities. It also provides criteria for adequate
access easements for maintenance equipment. The criteria also provides provisions for more
maintainable drainage facilities, such as the use of concrete trickle channels in detention ponds and
open channels.
Water Quality
The present criteria does not address water quality issues, whereas the new criteria addresses
potential toxic or hazardous discharges into municipal stormwater facilities and establishes the
authority to require compliance with any Federal or State discharge permit requirements that may
be imposed upon the City.
TABLE OF CONTENTS
CITY OF PUEBLO, COLORADO
STORM DRAINAGE DESIGN CRITERIA
AND DRAINAGE POLICIES
CHAPTER 1. GENERAL PROVISIONS
Page
1.1
Jurisdiction 1
1.2
Purpose and Intent 1
1.3
Modifications 1
1.4
Relationship to Other Standards 1
1.5
Permits and Other Requirements 2
1.6
Liability 2
CHAPTER 2. DRAINAGE POLICY
2.1
Introduction 3
2.2
Jurisdictional Boundaries 3
2.3
Dual Drainage Systems 3
2.4
Natural Drainage Channels 3
2.5
Erosion Control 3
2.6
Stormwater Detention 4
2.7
Dams 4
2.8
Irrigation Ditches and Canals 4
2.9
Culverts 4
2.10
Existing Drainage Problems 4
2.11
Cross Lot Drainage 5
2.12
Operation and Maintenance 5
2.13
Water Quality 5
CHAPTER 3. SUBMITTALS
3.1 General 6
3.2 Master Development Plan Drainage Report 6
3.2.1 Maps 6
3.2.2 Inflows from Upstream Basins 7
3.2.3 Downstream Impacts 7
3.2.4 Improvements Within the Master - Planned Area 7
3.2.5 Water Quality Impact 7
3.2.6 References 7
3.3 Subdivision, Resubdivision, Special Area Plan and
PUD Drainage Report 8
3.3.1 General Information 8
3.3.2 Major Drainage Basins and Sub -basins 8
3.3.3 Existing Drainage Studies and Reports 8
i
(Table of Contents Continued)
Page
3.3.4 Upstream Drainage Conditions
8
3.3.5 Onsite Drainage Considerations
8
3.3.6 Downstream Drainage Considerations
9
3.3.7 Erosion Control
9
3.3.8 Required Maps and Drawings
9
3.4 Abbreviated Drainage Report
11
3.5 Construction Plans and Specifications
12
3.5.1 Construction Plans and Specifications
12
3.5.2 Verification of Completion of Drainage Improvcments
12
CHAPTER 4. DRAINAGE DESIGN CRITERIA
4.1 General
13
4.2 Methods for Hydrologic Analysis
13
4.2.1 Rainfall
13
4.2.2 Runoff
13
4.3 Hydraulic Design Criteria
15
4.3.1 Streets
15
4.3.2 Storm Inlets
16
4.3.3 Culverts
17
4.3.4 Storm Sewers
19
4.3.5 Open Channels
22
4.3.6 Stormwater Detention Facilities
26
4.4 Erosion Control Plan
32
4.4.1 General Requirements
32
4.4.2 Required Information
33
4.4.3 Plan Implementation
33
4.5 Easement Requirements
34
4.6 Water Quality
35
LIST OF REFERENCES
36
LIST OF ABBREVIATIONS
37
11
APPENDICES
Time - Intensity- Frequency Curves
A -1
Time - Intensity- Frequency Tabulation
A -2
Incremental Rainfall Depth/Rewm Period
A -3
Time of Overland Sheet Flow
A-4
Travel Velocity of Concentrated Flow
A -5
Recommended Runoff Coefficients and Percent Imperviousness
A -6
Nomograph for Flow in Triangular Gutters
A -7
Reduction Factor for Allowable Gutter Capacity
SF -5
Local and Collector Streets
A -8
Reduction Factor for Allowable Gutter Capacity
When Approaching an Arterial Street
A -9
Adjustment for Gutter Capacity with
Non - Symmetrical Street Section
A -10
Type "S" Inlet Details
A -11
Type "W"' Inlet Details
A -12
Type 13 Grated Inlet Details
A -13
Capacity of Grated Inlet in Sump
A -14
Nomograph for Capacity of Curb Opening Inlets
in Sumps, Depression Depth 2"
A -15
Continuous Grade- Standard Curb Opening Inlet Charts
A -16 a, b, c
Inlet Control conditions for Culverts
A -17
Outlet Control conditions for Culverts
A -18
Inlet Control Nomograph
A -19
Outlet Control Nomograph
A -20
Storm Sewer Energy Loss Coefficient
A -21, 22, 23
Storm Sewer Size and Alignment Criteria
A -24
Standard Manhole Detail
A -25
Maximum Permissible Velocities for Grass Lined Channels
A -26
Trickle Channel
A-27,28
Detention Pond Outlet Configurations
A -29, 30, 31
Weir Flow Coefficients
A -32
Typical Grass Lined Channel Section
A -33
Standard Curb and Gutter Details
A -34
Map of Central Business District (CP -1)
B -1
STANDARD FORMS
Preliminary Drainage Report Checklist
SF -1
Final Drainage Report Checklist
SF -1 a
Inspection Report for Water Quality and
Stormwater Detention Ponds
SF -2
Culvert Rating
SF -3
Time of Concentration
SF-4
Storm Drainage System Design
(Rational Method)
SF -5
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STORM DRAINAGE DESIGN CRITERIA
AND DRAINAGE POLICIES
FOR
THE CITY OF PUEBLO
CHAPTER 1. GENERAL PROVISIONS
1.1 JURISDICTION
All of the policies and design criteria set forth in this manual are adopted pursuant to the authority
of Sections 4- 2 -2(8), 124-2(7), 12 -4 -5, 12- 4- 6(B)(3)(b) and 12- 4- 7(J)(5xc) of the 1971 Code of
Ordinances of the City of Pueblo (City), as amended, and shall apply to all land within the
incorporated areas of the City, and all facilities constructed on City Right- Of-Way (ROW), easements
dedicated for public use, and to all privately owned and maintained drainage facilities, including but
not limited to detention ponds, storm sewers, inlets, manholes, culverts, swales, and channels.
1.2 PURPOSE AND INTENT
It is the purpose and intent of the storm drainage design criteria and drainage policies contained in
this manual to promote the health, safety, convenience, and general welfare of the people of Pueblo,
Colorado. They are not intended, nor should they be construed, to create any new rights, remedies,
or benefits for any person, firm, corporation or entity.
All Master Development Plans, Subdivisions, Resubdivisions, Planned Unit Developments, Special
Area Plans, or other proposed construction submitted for approval under the provisions of Title 12,
Chapter 4 of the 1971 Code of Ordinances shall include adequate storm drainage provisions and shall
comply with the storm drainage design criteria and drainage policies set forth herein. All drainage
designs, analyses, and reports shall be prepared under the supervision of a Professional Engineer
(Engineer), licensed as such in the State of Colorado.
1.3 MODIFICATIONS
Requests for modifications to the design standards and criteria set forth herein shall be submitted in
accordance with Section 12-4 -10 of the 1971 Code of Ordinances.
1.4 RELATIONSHIP TO OTHER STANDARDS
Included in this manual are approved design methods, charts and tables, which when used will enable
the City to perform its review in a more efficient and expeditious manner. If the Engineer prefers to
use other methods, charts or tables, prior approval shall be obtained from the Director of Public
Works before submittal.
1
Design methods, charts and tables contained in the Urban Storm Drainage Criteria Manual
(USDCM) which is available through the Urban Drainage and Flood Control District (UD & FCD),
Suite 156 B, 2480 W. 26th Ave., Denver, Colorado, 80211, will generally be acceptable, except
where superseded by criteria contained herein.
1.5 PERMITS AND OTHER REQUIREMENTS
The developer and \or land owner shall be required to obtain all permits required by Federal, State,
or Local Agencies in conjunction with work covered under this manual, and shall be required to
comply with stonmwater requirements which may be imposed directly by such agencies or which may
be indirectly necessitated in order for the City to comply with any system wide permit which may be
issued to the City.
1.6 LIABILITY
The adoption of this manual shall not create any duty to any person, firm, corporation, or other entity
with regard to the application, enforcement or nonenforcement of this manual. No persons, firm,
corporation, or other entity shall have a private right of action, claim or civil liability remedy against
the City of Pueblo, or its officers, employees or agents, for any damage arising out of or in any way
connected with the adoption, application, enforcement, or nonenforcement of this manual. Nothing
in this manual shall be construed to create any liability under, or to waive any of the immunities,
limitations on liability, or other provisions of, the Governmental Immunity Act, C.R.S. 24 -10 -101 et
seq., or to waive any immunities or limitations on liability otherwise available to the City of Pueblo
or its officers, employees or agents.
Review and approval by the City of drainage improvements proposed in submittals does not relieve
the engineer who designed such improvements from his professional responsibilities for the adequacy
of the design of said improvements.
2
CHAPTER 2. DRAINAGE POLICY
2.1 INTRODUCTION
The policy statements contained in this chapter provide the basis for storm water management within
the City of Pueblo and are to be used in conjunction with the design criteria in this manual as
guidelines for the design and evaluation of all storm drainage facilities. The planning and design of
storm drainage facilities shall also comply with Colorado Law pertaining to drainage and water rights.
2.2 JURISDICTIONAL BOUNDARIES
Since all major drainage ways in the City of Pueblo cross jurisdictional boundaries between the City
of Pueblo and Pueblo County, it is important to recognize that regional cooperation is needed in the
planning and design of drainage systems.
The Policy of the City of Pueblo is to pursue an approach to drainage planning and design
which will consider regional drainage issues and promote the orderly growth of the City.
2.3 DUAL DRAINAGE SYSTEMS
The Policy of the City of Pueblo is to require that drainage systems be designed with the dual
purpose of:
a) Conveying runoff from the 100 -year design storm while minimizing health and
safety hazards, property damage, and disruption to emergency services.
b) Conveying runoff from the 5 -year design storm (25 -year design storm in the Central
Business District (CBD)) while minimizing inconvenience to people and traffic.
2.4 NATURAL DRAINAGE CHANNELS
The Policy of the City of Pueblo is to restrict development from within the 100 -year floodplain
of a natural drainage channel, or from within an approved erosion buffer zone for channels
with high erosion potential, whichever is greater, and to require that all provisions of Chapter
9, Title XVII of the Code of Ordinances concerning Flood Damage Prevention, be followed.
2.5 EROSION CONTROL
The Policy of the City of Pueblo is to require that adequate measures be implemented to
minimize soil erosion caused by development.
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2.6 STORMWATER DETENTION
The Policy of the City of Pueblo is to restrict the rate of stormwater runoff from developed
land to approximately the rate of runoff from the land in its historic or native condition.
On -site or regional stormwater detention facilities, designed in accordance with guidelines presented
in this manual, are acceptable methods of restricting peak flows. Regional detention facilities are
preferred over on -site facilities, and are more readily adaptable to recreational uses.
Exceptions to this Policy may be granted in the following cases:
a) When adequate drainage facilities are provided to convey the increased runoff from the
development to the floodplain of the Arkansas or Fountain River, or to a regional
detention facility which has been designed to accommodate the increased flows from
the development.
b) When it is determined by the city that there will be negligible downstream impacts from
the increased runoff due to the development.
2.7 DAMS
The Policy of the City of Pueblo is to require that all stormwater impoundment structures be
designed to meet the requirements of Article 87 of Title 37, Colorado Revised Statutes, and
regulations promulgated thereunder when applicable, and to prohibit development from
within hazardous areas created by the impoundment structure.
2.8 IRRIGATION DITCHES AND CANALS
The Policy of the City of Pueblo is to restrict the use of irrigation ditches and canals as outfalls
for drainage systems without the written, irrevocable consent of the owner, and unless such
use is shown to be without hazard by an engineering analysis. In the case of an abandoned
ditch or canal, provisions shall be made for ditch perpetuation prior to being selected for use
as an outfall or conveyance for drainage.
2.9 CULVERTS
The Policy of the City of Pueblo is to prohibit development from within ponding areas of
roadway or railroad culverts due to the 100 -year design storm.
2.10 EXISTING DRAINAGE PROBLEMS
The Policy of the City of Pueblo is to require that adequate measures be taken to insure that
development will not exacerbate existing drainage problems.
4
A drainage study was prepared in May of 1995 entitled "City of Pueblo - Master Storm Drainage
Study', which identified some of the major drainage problems in the City. A review of this study, and
discussions with the City staff, should take place in the initial stages of planning for development
within the City.
2.11 CROSS LOT DRAINAGE
The Policy of the City of Pueblo is to require that adequate measures be taken to prevent
uncontrolled cross lot drainage.
2.12 OPERATION AND MAINTENANCE
The Policy of the City of Pueblo is to require that drainage facilities be designed to minimize
maintenance costs and that adequate access be provided for maintenance equipment. Where
portions of the drainage system are on private property, adequate provisions shalt be made for
the tong term maintenance and operation of the facilities.
Whenever possible, city maintained storm sewers shall be located within dedicated city streets to
accommodate city cleaning equipment.
In residential developments the City may accept the maintenance responsibilities for stormwater
detention facilities on property that is dedicated to the City, under the terms and conditions of an
agreement approved by the City Council, which addresses access, revegetation and future
maintenance costs.
2.13 WATER QUALITY
The Policy of the City of Pueblo is to prohibit the discharge of any toxic or hazardous
substances into the storm water system which may cause the municipal discharge to violate
any water quality standard.
5
CHAPTER 3. SUBMITTALS
3.1 GENERAL
Al! drainage reports shall be typed on 8.5 "x11" paper and neatly bound in a folder which clearly
identifies the development. A copy of the general location map, drainage plan and erosion control
plan shall be neatly folded and included in a folder pocket at the back of the report. The report shall
begin with a completed copy of the "Drainage Report Checklist" (SP -1) signed by the Engineer.
The drainage report shall be transmitted with a cover letter prepared by the Professional Engineer
responsible for the preparation of the report, describing the project, noting any special conditions or
problems encountered on the site, certifying that the drainage design and analysis was completed
under his/hw supervision in accordance with the City of Pueblo's storm drainage design criteria, and
drainage policies and that the design is in conformance with City approved master plan for the
drainage basin, if one exists. The cover letter shall identify any modification to the criteria that may
be requested. The final report shall be signed and stamped by the Professional Engineer responsible
for the preparation of the report.
The body of the report shall contain the information described in Sections 3.2, 3.3 or 3.4 given below.
The report shall include an appendix which contains all drainage calculations, pipe strength and design
life calculations (if applicable), and design charts and tables used in the design.
Two copies of the report are required upon submittal, one of which will be returned to the Engineer
with comments or approval. If corrections or changes are required for approval by the City, two
revised copies of the drainage report, with all corrections or changes made, shall be submitted to the
City for approval. Incomplete reports will not be accepted for review.
3.2 MASTER DEVELOPMENT PLAN DRAINAGE REPORT
The drainage report for master development plans shall include, at a minimum, the following:
3.2.1 Maps
A map /maps showing the following information:
A. Township, Range, Section, 1/4 Section and general location
B. The boundary of the masterplanned area
C. Existing and proposed zoning
D. Existing topography with a maximum 10 -foot contour interval
6
E. Identification of all drainage basins tributary to the masterplanned area
F. All 100 -year floodplains within or adjacent to the masterplanned area
G. Proposed street layout within the masterplanned area
H. Adjacent developments, masterplans or subdivisions
I. Drainage paths, with historic and developed flow rates identified at basin and
sub -basin boundaries
J. Natural drainage channels, man made channels, bridges, culverts, storm sewers,
detention ponds, and major erosion control features
3.2.2 Inflows from Upstream Basins
Discussion and analysis of the 100 -year peak flows from all offsite tributary areas entering the
masterplanned area and the manner in which this drainage will be conveyed through the proposed
development.
3.2.3 Downstream Impacts
Discussion and analysis of the I00 -year peak flows leaving the masterplanned area and their impact
on downstream properties and drainage facilities. Include discussion of any proposed detention
facilities. If downstream drainage improvements are required, provide preliminary cost estimates and
a phasing plan.
3.2.4 Improvements within the Masterplanned Area
Discussion of proposed drainage improvements within the masterplanned area and preliminary cost
estimates of those improvements. A discussion of planned phasing of the improvements should be
included.
3.2.5 Water Quality Impact
Discussion of the general concept of stormwater quality management planning and water -quality
objectives proposed in the master plan. Discussion of measures used to facilitate the general concept
for some specific sites if applicable. For details regarding water quality, refer to USDCM Volume 3 .
This discussion will pertain to all residential development of 5 acres or greater in area, and all
commercial and industrial development.
3.2.6 References
Include references to existing drainage studies for any tributary areas, if any.
7
3.3 Subdivision, Resubdivision, Special Area Plan and PUD Drainage Reports
Drainage reports for submittals under this section shall contain, at a minimum, the following
information:
3.3.1 General information
Provide general project description, names of adjacent subdivisions or unsubdivided developments,
area affected by the development in acres, types of soil and ground cover (correlate to SCS types),
description of major drainageways that impact or are impacted by the development, existing utilities
that may impact or may be impacted by proposed drainage facilities, general topography and erosion
characteristics.
3.3.2 Major Drainage Basins and Sub - basins
Discuss major basin and sub -basin drainage characteristics that affect the proposed development.
Include overall area, topography, SCS soil types, ground cover, major drainageways and facilities,
obstructions, and existing adjacent developments.
3.3.3 Existing Drainage Studies and Reports
Reference all existing drainage studies and reports that are related to the drainage of the proposed
development, such as master development plan drainage reports, subdivision drainage reports, flood
hazard delineation reports, flood insurance rate maps, etc..
3.3.4 Upstream Drainage Conditions
Discuss upstream drainage patterns and their impact on the proposed development. Identify locations
and flow rates of drainage entering the site. Provide detailed hydrologic analysis using 100 -year
design storm criteria and fully developed basin conditions unless otherwise approved by the City.
The City's zoning maps shall be used in determining the appropriate runoff characteristics. When
dealing with large basins that lie partially outside of the city limits, confer with city staff prior to
making runoff design assumptions.
The effects of stormwater detention will only be taken into account in the case of existing publicly
controlled regional detention facilities.
3.3.5 Onsite Drainage Considerations
Discuss existing and proposed drainage patterns within the development site, and how upstream
drainage entering the site will be conveyed through the site. Demonstrate through detailed hydrologic
and hydraulic analysis that sufficient right of way or easement is provided to convey all drainage
through or adjacent to the development. Provide detailed engineering calculations and copies of all
design charts, tables and figures used in the design of streets, inlets, culverts, storm sewers, channels,
detention facilities or other drainage facilities to be constructed in the development. Discuss
8
maintenance of drainage facilities and identify which facilities are anticipated to be maintained by the
owner of the property and which are anticipated to be maintained by the City. Discuss right -of -way
and easement requirements for access and maintenance of drainage facilities. If natural drainage
channels lie within or are adjacent to the development, discuss floodplain and channel erosion issues.
Discuss any other drainage issues that are pertinent to the proposed development.
3.3.6 Downstream Drainage Considerations
Identify locations and 100 -year peak flow rates of drainage leaving the site and discuss their impact
on downstream facilities and properties. Discuss any downstream improvements that are to be made
in conjunction with the development. Provide detailed supportive hydrologic and hydraulic analyses.
3.3.7 Erosion Control
Discuss erosion control measures and management practices to be utilized within the subdivision to
reduce soil pollutant loads in stormwater runoff. Address both temporary and permanent facilities and
time frames to be utilized for the construction of all erosion control measures. Discuss the
maintenance of temporary and permanent facilities.
3.3.8 Required Maps and Drawings
A. General Location Map
A map of sufficient detail to identify drainage flow patterns entering and leaving the
development and general drainage patterns within the development. The map shall
be at a scale of 1"= 1000' to I"= 8000' and shall show the path of all drainage from
the upper end of any offsite basins to the defined major drainageways. The map shall
identify any major construction (i.e. development, irrigation ditches, existing detention
facilities, bridges, culverts, storm sewers, etc.) along the entire path of drainage way.
B. Floodplain Information
Include FEMA Floodplain Map if applicable, with the location of the development
identified.
Identify the 100 -year floodplain of all natural drainage channels within or adjacent to
the development.
C. Drainage Plan
A drainage plan(s) at a scale of 1"= 20' to 1"= 200' on a 24 "x 36" format shall be
included. The plan(s) shall include the following information. (Show existing features
in dashed lines and proposed features in solid lines.)
7
Title block which identifies the project, the date, the firm that prepared the
plans, and the name of the preparer.
2. A statement by the Engineer that the plan was prepared under his/her
supervision, Professional Engineer's license number, and Engineer's initials
indicating the plan has been checked for accuracy.
Overall drainage basin boundary and sub -basin boundaries. Show flow
direction with arrows. Identify location and quantity (cfs) of concentrated
flows entering and leaving the development. Show downstream receiving
facilities with all pertinent information.
4. Existing and proposed contours at 2 foot maximum intervals. In terrain where
slopes exceed 10%, the maximum contour interval can be 10 feet. The
contours should extend at least 50 feet from all project boundaries, further if
necessary, to show drainage relationships with adjacent properties.
Property lines and easements with purposes noted, including maintenance
access easements if any. Show directional flow arrows reflecting individual
lot drainage.
6. Streets and right of way lines. Identify type of curbing at the street edge.
Show cross pans and directional flow arrows.
7. Accumulation of flows at drainage design points. Show path(s) chosen for
computation of time of concentration.
Existing and proposed utilities. Identify type and size where applicable.
9. Existing and proposed storm sewers, inlets and manholes. Identify size, slope,
material and design flow (cfs) in storm sewers and inlet runs. Show
directional flow arrows. Identify type and length of inlets, diameter of
manholes and any special manhole features required by the Engineer. (Show
design water surface profiles on construction drawing profile.)
10. Existing and proposed culverts. Identify size, material and design flow (cfs).
Show limits of ponding inundation for 100 -year design storm. Show
headwalls, wingwalls and any erosion control structures.
11. Existing and proposed open channels. Show typical cross sections and water
surface elevation. Identify type of channel lining, design flow rate (cfs) and
velocity. Show erosion control features and trickle channel details if any.
(Show 100 -year water surface profile on construction drawing profile.)
10
12. Existing and proposed detention ponds. Provide grading plan and indicate
storage volume provided for both the 10 -year and 100 -year ponding
elevations. Delineate limits of inundation for the 100 -year ponding level.
Provide details for the outlet structure and emergency spillway. Show the
path of emergency overflow and provide details of any erosion control
measures to be used. Show trickle channel, slope and details.
13. Existing natural channels within 150 feet of the boundary of the project.
Delineate 100 -year flood plain or erosion buffer zone, whichever is greater.
Identify existing or proposed erosion control measures if any. Show 100 -year
water surface profile when required. Show existing or proposed bridges or
culverts.
14. Existing irrigation ditches or canals and all pertinent information.
15. Professional Engineer's seal and signature on record copy.
16. Grading and Erosion Control Plan
A mylar of the drainage plan shall be provided to the City for permanent record.
3.4 ABBREVIATED DRAINAGE REPORT
In the case of a resubdivision, where a complete drainage report has previously been approved by the
City for the original subdivision, and the resubdivision does not significantly alter the concepts of the
original drainage report, or in other cases where an abbreviated drainage report is determined to be
appropriate by the City, the Engineer may submit an abbreviated drainage report which conforms to
the provisions of this Section.
The report shall generally follow the requirements of Section 3. 1, and contain a cover letter by the
Engineer which describes the Project and references the drainage report under which the Project will
be constructed. Any changes to the drainage design of the original subdivision shall be fully described
and documented in accordance with all provisions of the drainage criteria contained in this manual.
If no design changes are to be made, the Engineer shall so state. The City may require drainage
design or analysis in addition to that given in the original drainage report if that report is deemed by
the City to be incomplete. This may include requiring provisions for erosion control and flow arrows
indicating lot drainage which had not been included in the original drainage report. The report shall
include copies of the site map and revised drainage plan if applicable.
3.5 CONSTRUCTION PLANS AND SPECIFICATIONS
3.5.1 Construction Plans and Specifications
Where drainage improvements are to be constructed in accordance with the approved Drainage
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Report, two copies of construction plans (on 24 "x36" sheets) and specifications shall be submitted
to the City for review and approval. A mylar reproducible copy of the approved plans shall be
provided to the City for permanent record keeping. In general, the plans and specifications must
include complete information necessary for construction. The plans shall include the following:
A. Storm sewers (plan and profile), inlets, and outlets, with details (to be included on
street construction plans). Design water surface profile.
B. Culverts, end sections, and inlet/outlet erosion control structures (to be included on
street construction plans).
C. Channels, channel drops, checks, ditches and swales ('include typical cross sections
and profile). 100 -year water surface profile.
D. Detention pond grading plan, trickle channel profile and cross sections, outlet
structure details and revegetation specifications.
E. Site grading plan.
F. Erosion control facilities and details.
G. Maintenance access roads, profile and cross section.
H. Finished floor elevations of buildings adjacent to floodplains or open channels.
I. 100 -year water surface elevations if applicable.
Professional Engineer's Seal and signature on Record Copy.
K. Title block which identifies the Project, the date, the firm that prepared the plans, the
initials of the preparer and the Professional Engineer that is responsible for the design.
3.5.2 Verification of Completion of Drainage Improvements
Upon completion of construction of all drainage improvements which are included in the drainage
plan, but not under the City's jurisdiction; the Registered Professional Engineer responsible for the
design of the drainage facilities shall verify in writing to the City that all such improvements have been
completed in accordance with the approved plans. This is to include all drainage improvements
constructed on private property.
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CHAPTER 4. DRAINAGE DESIGN CRITERIA
4.1 GENERAL
The design criteria presented in this section provides minimum guidelines for the design of drainage
facilities within the City of Pueblo. This criteria should not be construed as preventing the Engineer
from providing more capacity in the drainage system if he/she deems it appropriate.
The criteria should only be used by Engineers who have a through knowledge of hydraulics and
drainage principles.
The Engineer should not assume that the City's review of the drainage report will catch errors in the
design. Depending upon staffing and other demands placed upon the City Engineering Division, the
City may rely totally upon the engineer's certification that the drainage design meets the City's design
criteria and sound engineering design principles. As stated in Section 1.6, the Engineer is completely
responsible for the adequacy of the design.
4.2 METHODS FOR HYDROLOGIC ANALYSIS
4.2.1 Rainfall
Rainfall intensity data for the Pueblo area has been incorporated into the Time - Intensity- Frequency
Curves and Time - Intensity- Frequency Tabulation, shown in Appendix A -1 and Appendix A -2
respectively. Incremental rainfall depths for various recurrence intervals are tabulated in Appendix
A -3. These design curves and tabulated data shall be used where applicable for the basis of runoff
calculations in this manual.
4.2.2 Runoff
The following runoff computational methods are acceptable for determining design storm flows:
BASIN AREA ALLOWABLE METHOD
10 acres or less Rational Method
10 acres to 160 acres Rational Method,
SCS (TR -55),
CUHP
160 acres or greater SCS: Rural Areas - Imperviousness < 25%
CUHP: Urban Areas - Imperviousness > 25%
SCS (TR -55) = Soil Conservation Service Method.
Reference: Procedures for Determining Peak Flows in Colorado SCS,
March, 1984.
13
CUHP = Colorado Urban Hydrograph Procedure.
Reference: USDCM. VOLUME 1 , UD &FCD, March, 1969,
revised May, 1984.
In the Rational Method, the following formula is used to determine runoff at a design point:
Q =CIA
where
Q = maximum rate of runoff (cfs)
A = tributary area (acres)
C = runoff coefficient
I = average rainfall intensity for a duration equal to the time of concentration.
The table in Appendix A-6 provides acceptable runoff coefficients of various ground covers for
different design storm frequencies. The runoff coefficient used in the analysis shall be based on the
developed land use and not on the existing land condition, except for historic flow calculations. In
cases where the tributary area will include a combination of ground cover conditions, a weighted
runoff coefficient shall be used.
The rainfall intensity, I, shall be determined from the chart in Appendix A -1 corresponding to the
calculated tr. at a design point.
The time of concentration is defined as:
t, = t + tt (4.2 -2)
Where t, = time of concentration (minutes)
t = overland sheet flow time (minutes)
t = travel time of concentrated flow in gutter, ditch, channel, storm sewer, etc.
(minutes)
The travel time, t., can be determined from the chart in Appendix A4 and t, can be calculated based
on the velocity found in Appendix A -5. Equation (4.2 -2) can be used for a non - urbanized basin or
an urbanized basin. However, in an urbanized basin, t. at the first design point should not exceed the
t, calculated using following equation:
t ` 180 + 10
where
(4.2 -3)
t, = time of concentration at the first design point in an urban watershed (minutes)
L = watershed flow path length (feet)
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Normally, equation (4.2 -3) will result in a lesser time of concentration at the first design point and
will govern in an urbanized watershed. For the design of a storm drainage system, the minimum time
of concentration at the first design point shall be 10 minutes.
For more details regarding the Rational Method, refer to USDCK Volume 1. Runoff
4.3 HYDRAULIC DESIGN CRITERIA
4.3.1 Streets
A. Maximum allowable street encroachment based upon 5 -year (25 -year in CBD) design
storm:
Street Classification Maximum Encroachment
Minor & Collector No curb overtopping. Flow spread must leave
at least one 10 foot lane free of water.
Arterial No curb overtopping. Flow spread must leave
at least one 10 foot lane in each direction free
of water.
B. Maximum allowable street encroachment based upon the 100 -year design storm:
Street Classification Maximum Encroachment
Minor & Collector The depth of water at gutter flow line shall not
exceed 12 inches. The width of flow shall not
exceed the R.O.W. limits. No buildings shall
be inundated at the ground floor elevation.
Arterial The depth of water shall not exceed. 6 inches at
the street crown, or 12 inches at the gutter
flowline. The width of flow shall not exceed the
R.O.W. limits. No building shall be inundated
at the ground floor elevation.
C. Maximum allowable cross street flow:
5 -year Design Storm
Street Classification (25 -years in CBD) 100 -year Design Storm
Minor 6 inches in depth in 12 inches in depth at
cross pan gutter flowline
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Collector Where cross pans are
allowed, depth of flow
shall not exceed 6 inches
Arterial
None allowed
12 inches in depth at
at gutter flowline.
6 inches over crown
Cross street flows occur when the flow in the gutter spreads across the street crown,
when the capacity of a roadway culvert is exceeded and the flow overtops the street
crown, or when cross pans are used.
D. Allowable Street Capacity
After the allowable street encroachment has been established by the criteria given in
section (A) and (B) above, the allowable street capacity may be determined using the
nomograph shown in Appendix A -7 for the 5 -year (25 -year in CBD) design storm,
or the Manning's Equation (see section 4.3 -5B) for the 100 -year design storm, and
applying a reduction factor as determined by the appropriate graph as shown in
Appendix A -8 or A -9. A roughness factor (n) of 0.017 shall be used for concrete and
asphalt surfaces in the above equation or nomograph. A cross slope of 210 shall be
used in the calculations unless otherwise approved by the City. (See Appendix A -34
for Standard Curb and Gutter details.)
For non symmetrical street sections, adjust the total gutter capacity by reducing the
allowable gutter capacity for the gutter with the higher flowline or for the entire
section when property line slopes are different. See Appendix A -10 for additional
information.
E. Allowable Ponding
The maximum allowable street encroachment due to ponding shall be limited to the
same criteria given in sections (A) and (B) above.
The term ponding shall refer to areas where runoff is restricted to the street surface
by sump inlets, street intersections, low points, intersections with drainage channels,
etc.
4.3.2 Storm Inlets
Storm inlets shall be designed in accordance with the following criteria:
A. Standard Inlets
Storm inlets used within the public right of way shall conform to the City of Pueblo
standard type "S" curb opening inlet for sump conditions and type "W" curb opening
inlet for continuous grade conditions. Where grated inlets are allowed they shall
conform to the City of Pueblo standard type "13" grated inlet.
Details of the City's standard inlets are shown in Appendix A -11, A -12, A -13.
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Other inlet designs may only be used within the public right of way with prior approval
by the Director of Public Works.
B. Required Inlet Locations
Storm inlets shall be installed where sump conditions exist or where the allowable
street capacity is exceeded. Unless cross pans have been approved at an intersection,
inlets shall also be placed at the upstream side of each intersection in such a manner
that the downstream end of the inlet is located not less than ten (10) feet upstream
from the point of tangency of the curb radius.
The length of an inlet shall not exceed twenty (20) feet, and no more than one inlet
shall be allowed to be placed adjacent to any residential lot.
Inlets shall be spaced so as not to interfere with driveway access.
C. Allowable Inlet Capacity
1. Type 13 Grated Inlet
The theoretical inlet capacity of a type 13 grated inlet in sump condition shall
be determined from the chart in Appendix A-14. The allowable capacity shall
be equal to 50% of the theoretical capacity to account for debris clogging.
2. Type "S" Curb Opening Inlet
The theoretical inlet capacity of a type "S" curb opening inlet in sump
condition shall be determined from the chart in Appendix A-15. The allowable
capacity shall be equal to 80% of the theoretical capacity to account for debris
clogging.
3. Type "W" Curb Opening Inlet
The theoretical inlet capacity of a type "W" curb opening inlet on continuous
grade shall be determined from the charts in Appendix A -16. The allowable
capacity shall be equal to 80% of the theoretical capacity to account for debris
clogging.
Generally, inlets on continuous grade should not be designed for interception
rates greater than 75 %.
D. Minimum Inlet Discharge Pipe Size
The minimum inlet discharge pipe size shall be IS" diameter.
4.3.3 Culverts
Culverts shall be designed in accordance with the following criteria:
A. Design Capacity
Culverts installed beneath minor and collector streets shall be designed for runoff from
the 10-year design storm and those installed beneath arterial streets shall be designed
for runoff from the 100 -year design storm.
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Culverts installed beneath State Highways shall be designed in accordance with criteria
established by the Colorado Department of Transportation.
Design aids for culvert design are provided in the Appendix, sheets A -17, 18,19 & 20.
For additional information refer to USDCM.
All culvert designs shall include an analysis that determines whether inlet or outlet
control conditions govern.
Ponding above culvert entrances will not be allowed if such ponding will cause
property or roadway damage. The limits of ponding area for the 100 -year design
storm runoff shall be shown on the drainage plan, and drainage easements shall be
established to restrict development from within this ponding area.
B. Allowable Street Overtopping
The maximum overtopping of a street of any classification shall be the lessor of 6
inches in depth at the street crown or 12 inches in depth at the gutter flowline, when
flows are computed for the 100 -year design storm. There shall be no overtopping of
a street of any classification for flows computed for the 5 -year design storm.
C. Velocity Limitations
The minimum allowable flow velocity within a culvert shall be 3 feet per second, using
estimated flows from the 5 -year design storm.
The maximum allowable flow velocity at the outlet of the culvert is limited to
maximum channel velocities given in Section 4.3.5.
Where discharge velocities exceed this criteria, an approved energy dissipating
structure must be constructed at the outlet.
For aid in designing energy dissipating structures, refer to USDCM, Volume 2,
Structures.
D. Minimum Pipe Size
The minimum culvert pipe size shall be 18 -inch diameter round pipe, 22" x 13" arch
pipe, or 23" x 14" eliptical pipe.
E. Multiple Pipe Culverts
Where multiple -pipe culvert installations have been approved by the City, the spacing
between pipes shall be equal to one - half (' /z) of the outside pipe diameter or three feet,
whichever is less.
F. Inlet and Outlet Sections
Unless otherwise approved, culvert inlet and outlet sections shall include approved
headwalls with wingwalls, or in the case of outlets a flared end section. Both must
be located a sufficient distance from the edge of the shoulder to allow for a maximum
slope of 3 horizontal to 1 vertical to the back of the structure.
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G. Structural Design
The structural design of culverts shall conform to those methods and criteria
recommended by the manufacturer for the culvert type and for the conditions found
at the installation site. Where culverts are exposed to vehicular traffic, they shall meet
the minimum standards set forth in the current American Association of State
Highway and Transporation Officials (AASHTO) Standard Specifications for Highway
Bridges.
For large structures or where groundwater is a problem, the design shall include
necessary provisions to resist hydrostatic uplift forces that could result in failure of
the structure.
Unless otherwise approved, culverts shall be constructed of reinforced concrete pipe
(RCP) made with Type V sulfate resistant cement.
4.3.4 Storm Sewers
A. General Design Requirements
A storm sewer system shall be required whenever the allowable street capacities as
determined in Section 4.3.1 are exceeded. Consideration must be given to both the
5 -year design storm (25 -year in CBD) and the 100 -year design storm criteria for
maximum street encroachment.
Storm sewers shall be designed as non - pressurized conduits, using the Manning's
Equation or approved nomographs to determine pipe capacity and flow velocity.
Conduits shall be checked for critical slope to insure they are operating under normal
flow conditions and not inlet control. The hydraulic design of the storm sewer system
shall take into account the effect of backwater and allow for all energy losses in the
system.
The Engineer shall demonstrate through detailed backwater analysis that the hydraulic
grade line of the storm sewer system does not rise above the crown of the pipe for
the 5 -year design storm (25 -year in CBD). Energy loss coefficients associated with
common storm sewer structures and appurtenances are given in Appendix A -21, A -22,
and A -23.
When checking the combined conveyance system, including the street and storm
sewer, for the 100 -year design storm, segments of the storm sewer system may have
to be enlarged to meet the maximum street encroachment criteria.
Under the following circumstances, pressurized conditions in the storm sewer system
may be allowed with the approval of the Director of Public Works:
1. Where existing storm sewers are utilized to alleviate drainage problems.
In this case the hydraulic grade line shall not be allowed to rise above the
gutter flow line.
2. Where physical constraints such as existing underground utilities require
the crown of the storm sewer to be held below the hydraulic grade line.
3. When checking the combined street and storm sewer conveyance system
for the 100 -year design storm. In this case the hydraulic grade line shall
not rise above the gutter flow line.
19
Acceptable Manning's Roughness Coefficients "n" for various pipe materials are given
below:
Reinforced Concrete Pipe
0.015
High Density Polyethylene:
Smooth Wall
0.010
Corrugated
18" -36"
0.020
15"
0.018
Poly Vinyl Chloride (SDR35)
Smooth Wall
0.010
Ribbed
0.012
B. Allowable Flow Velocity
The minimum flow velocity in any part of the storm sewer system shall be three (3)
feet per second, assuming the conduit is flowing at one half full. The maximum flow
velocity in conduits susceptible to abrasion shall be fifteen (15) feet per second.
C. Storm Sewer Outlets
Storm sewer outlets shall be constructed with either flared end sections or head walls
and wing walls. Scour and erosion protection shall be provided in accordance with
practices described in the Urban Storm Drainage Criteria Manual, Volume 2,
Structures Section.
Storm sewer outlets greater than 30" in diameter, in locations where unauthorized
entry is likely such as near schools, parks and residential areas, shall be provided with
grates meeting the following requirements:
Grating shall be constructed of steel bars with a minimum diameter of 5/8 ".
Reinforcing bars shall not be used.
2. Welded connections shall be 1/4" minimum.
3. Spacing between bars shall be 6 ".
4. All exposed steel shall be galvanized in accordance with AASHTO M 111.
Welded joints shall be protected with a rust preventive paint.
6. Grates shall be secured to the headwall or end section by removable devices
such as bolts or hinges to allow maintenance access, prevent vandalism, and
prohibit entrance by children.
We
D. Horizontal Alignment and Required Clearances
The minimum clearances between storm sewer and water main or sanitary sewer shall
be 10 feet from outside of pipe to outside of pipe unless otherwise approved by the
City for special cases.
In general, storm sewer alignment between manholes shall be straight. However,
storm sewers may be constructed with curvilinear alignment by using pipe bends up
to 45* on pipe 36" diameter or greater, or Radius pipe conforming to the criteria
given in Appendix A -24.
E. Vertical Alignment and Required Clearances
Storm sewers shall be installed on a uniform grade between manholes. Unless
otherwise approved, a minimum cover of 3' -0" shall be provided over the crown of
the pipe. In no case shall the crown of the pipe extend into the street subgrade, nor
have less than 1'-0 of cover.
Final grades and invert elevations shall conform to the hydraulic design of the system,
as documented in the drainage report.
The minimum vertical clearance between storm sewer and water lines or sanitary
sewer lines shall be 12" unless otherwise approved.
F
Manholes
Manholes shall be required whenever there is a change in size, direction, elevation,
grade, or where there is a junction of two or more sewers, except as provided in
paragraph (D) above. The Engineer shall provide details for shaping the interior of
manholes when required to meet hydraulic design assumptions.
The maximum spacing between manholes shall be 400' for sizes 15" to 36" and 500'
for 42" and larger diameter pipes. (See Appendix A -25 for Standard Manhole details.)
The required manhole size shall be as follows:
SEWER DIAMETER
18"
21" to 36"
42" and larger
WX
MANHOLE DIAMETER
4'
5'
Type II Manhole
Minimum Pipe Size
The minimum allowable pipe size diameter for main lines and detention outlets is 18"
and for inlet runs is 15 ".
H. Pipe Materials and Pipe Strength
For allowable storm sewer pipe materials refer to City of Pueblo Standard
Specifications, Article 13.
Storm sewers shall be designed in accordance with manufacturer recommendations
for project site specific loading conditions. Storm sewers which are subject to
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vehicular traffic shall be designed to support all dead loads plus AASHTO HS 20-44
live load.
4.3.5 Open Channels
A Design Flows
Open channels which are used for urban drainage must be capable of conveying runoff
from all tributary lands, using the 100 -year design storm criteria. Runoff from lands
within the city limits shall be based upon existing zoning maps, assuming fully
developed conditions. Runoff from lands outside the city limits shall be based upon
existing development and land use, however sufficient right of way or easement shall
be provided to allow for future channel improvements assuming tributary lands outside
of the city limits are fully developed.
Reductions in peak flow rates will only be allowed for regional detention facilities that
are in place within the tributary area and controlled by public agencies.
B. Man Made Channels
Design Methods
Man made channels may be designed and analyzed using the Manning's
Equation and Froude Number as given below. Unless otherwise approved,
a water surface profile shall be computed for all channels and clearly shown
on the construction plans. Computation of the water surface profile shall
utilize standard backwater analysis methods, taking into account all energy
losses in the channel including bends, drops, culverts, bridge openings, channel
friction, etc. Complete documentation of backwater calculations shall be
included in the drainage report.
a. Manning's Equation:
Q = 1.49 AR S'"
n
V = Q
A
where: Q = Channel discharge rate (cfs)
A = Cross - sectional area of flow (square feet)
V = Velocity of flow (fps)
n = Coefficient of channel roughness
R = Hydraulic radius of channel = AT (feet)
P = Wetted perimeter of channel (feet)
S = Slope of energy gradient (feet/feet)
22
b. Froude Number
F= V
4 5
where F = Froude Number -
F <1.0 : subcritical flow
F=1.0: critical flow
F> 1.0 : supercritical flow
V = flow velocity (fps)
g = acceleration of gravity = 32.2 (ft/sec)
D = hydraulic depth = A/T (feet)
A = cross - sectional area of flow (square feet)
T = top width of flow area (feet)
2. Channel Linings
Unless otherwise approved, man made channels shall be grass lined. Where
existing flooding problems need to be solved, and where right of way is limited,
concrete, rock, or other artificial channel linings may be approved.
a. Design Criteria for Grass Lined Channels
Grass lined channels shall be designed in accordance with the following
criteria:
(1) Side Slopes
Side slopes shall not be steeper than four horizontal to one
vertical (4:1).
(2) Bottom Width
Minimum bottom width shall be 8.0 feet when flows exceed
400 cfs.
(3) Depth
Maximum flow depth shall not exceed 5.0 feet in areas outside
of trickle channel.
(4) Velocity
Maximum average flow velocity for the 100 -year design storm
shall not exceed the values given in Appendix A -26. The
minimum average velocity shall not be less than 2.0 feet per
second when using the 5 -year design storm.
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(5) Manning's Roughness Coefficient "n"
For straight and uniform grass lined channels with no brush or
debris, the following minimum roughness coefficients are to be
used in the Manning's Equation:
Depth of flow < 2.0 feet ......... n = 0.060
Depth of flow> 2.0 feet ......... n = 0.035
(6) Froude Number
The Froude Number shall not exceed 0.8 for grass linings in
erosion resistant soils, or 0.6 for grass linings in easily erodible
soils.
(7) Freeboard
Freeboard shall not be less than that calculated as follows:
HFB = 1.0 + V2 /2g
Where H = freeboard height (feet)
V = average channel velocity (fps)
g = acceleration of gravity = 32.2 ft/sec'
The minimum freeboard shall be 1.0 -feet above the computed
100 -year water surface elevation. Freeboard shall not be
obtained by the construction of levees.
In addition to the freeboard calculated above, additional
freeboard must be provided at bends to account for super -
elevation of the water surface.
An approximation of the superelevation, h (ft), at a channel
bend with velocity V (fps), centerline radius of curvature
r -sub c (ft), and top width of channel, Tw (ft), can be obtained
from the following equation:
h = V /gr,
The freeboard shall be measured above the superelevation water
surface.
(8) Curvature
Centerline curvature of curved channels shall have a radius of
at least twice the top width of the 100 -year design flow, but not
less than 100 feet.
(9) Trickle Channel
Unless otherwise approved, a trickle channel shall be provided
meeting the standards shown on Appendix A -27 or A -28.
24
Trickle channels shall be designed to carry a minimum flow of
1% of the 100 -year design flow.
(10) Structures
Where topographic or other constrainu require checks or other
hydraulic structures to control velocity, refer to USDCM,
Volume 2 "Structures" for design guidelines. When used,
provide complete design documentation in the drainage report.
b. Design Criteria for Concrete and Rock Lined Channels
Concrete and rock lined channels, where approved, shall be designed
in accordance with guidelines presented in USDCK Volume 2, Major
Drainage, Sections 2.2 and 5 respectively.
When used, complete design documentation shall be provided in the
drainage report.
C. Natural Drainage Channels
Flood Plain Delineation
Where a natural drainage channel is adjacent to, or within a proposed
development, the 100 -year flood plain of the channel shall be determined
and delineated on the subdivision plat.
The 100 -year floodplain shall be established by a thorough engineering analysis
which takes into account all physical properties of the channel and energy
losses along the channel. Appropriate allowances for future bridges or culverts
which can raise the water surface profiles and cause the floodplain to be
extended shall be included in the analysis. Design flows shall be in accordance
with Section 4.3.5 A The 100 -year water surface profile shall be determined
and shown on the drainage plan. Complete documentation shall be included
in the drainage report.
2. Erosion Buffer Zone
For channels in highly erodible soils, the 100 -year floodplain may be contained
entirely within the vertical banks of the channel, however, due to bank erosion
the width of the channel may increase with time. In these cases, an erosion
buffer zone must be established and delineated on the subdivision plat. The
methods used to determine the erosion buffer zone must be approved by the
City, and complete documentation included in the drainage report.
Flood plain analysis and channel erosion analysis shall be done by a
professional engineer with specific training and experience in these subjects.
Where these analyses are required, a resume of the Engineer's training and
experience shall be included with the drainage report.
25
3. Froude Number
Natural channel segments which have a Froude Number greater than 0.95 for
the 100 -year peak flow shall be protected from erosion in accordance with
design guidelines presented in USDCM, Volume 2, Major Drainage.
Where required, complete documentation shall be included in the drainage
report.
4. Roughness Factors
Roughness factors (n), which are representative of unmaintained channel
conditions, shall be used for the analysis of water surface profiles.
Roughness factors (n), which are representative of maintained channel
conditions, shall be used to determine velocity limitations.
5. Grade Control Structures
Where necessary, grade control structures as described in USDCM, Volume
2, Structures, shall be constructed at regular intervals to decrease the thalweg
slope and to control erosion. When used, complete documentation shall be
included in the drainage report.
6. Section 404 Permit
Modification of channels within the normal high water fine may require a
US Army Corps of Engineers Section 404 permit. It is the responsibility of
the Engineer to obtain a 404 permit if required.
4.3.6 Stormwater Detention Facilities
Whenever site development increases stormwater runoff, downstream drainage facilities must either
be improved to accommodate the increased flows, or detention facilities must be constructed to
reduce peak flows from the site to the level that existed prior to the development, or to levels that
can be accommodated by existing downstream drainage facilities. Stormwater detention facilities
shall, at a minimum, meet the criteria of this section.
A. Storage Capacity and Release Rates
Stormwater detention facilities shall be designed with adequate storage capacity to
insure that release rates do not exceed either the 10 -year or 100 -year historic flow
rates from the tributary basin. Inflows to the detention facility shall be calculated
assuming fully developed conditions in the tributary basin
Examples of outlet designs are shown in Appendix A -29, A -30, and A -31, and
discussed in section J below.
The following methods may be used to determine storage capacity and release rates:
Emperical Equation Design Method
The Equation Design Method may be used for drainage basins of 20
acres or less, where flows entering the detention facility come from the
26
subject property only and flows are not routed from one detention
facility to another.
The minimum required storage capacities and the allowable release
rates at the ponding depths corresponding to the 10- and 100 -year
volumes shall be determined using the following equations:
Minimum required storage capacity
V = KA
For the 100 -year storm event:
K100 _ ( 1.78P - 0.002P - 3.56)/ 1000
For the 10 -year storm event:
K lo = (0.95P - 1.90)/1000
where V = minimum required storage capacity for the 100- or 10 -year
storm (acre -ft)
P = developed basin imperviousness ( %)
A= tributary area (acres)
Allowable Release Rates:
The allowable release rate shall be equal to the total drainage basin area (acres)
times a factor (cfs/acre) from the table below, based on the soil type:
CONTROL FREQUENCY SCS SOIL GROUP TYPES
A B C&D
10 -year 0.13 0.23 0.30
100 -year 0.50 0.85 1.00
The predominate soil group for the total basin area tributary to the detention
pond shall be used for determining the allowable release rate. Soil
information is available in the publication Soil Survey of the Pueblo Area,
Colorado USDA, SCS, June, 1979.
27
2. Colorado Urban Hydrograph Procedure (CUHP) and Soil Conservation
Service (SCS) Unit Hydrograph Procedure
For basins greater than 20 acres in size or where drainage is routed through
more than one detention facility, the following methods shall be used:
SCS Unit Hydrograph Procedure - for rural areas with impervious area less
than 25%
Colorado Urban Hydrograph Procedure - for urban areas with impervious
area greater than 25 %.
Refer to USDCM, Volume 1 for procedure details.
B. Dams Requiring State Approval
Any dam used to impound more than 100 acre feet of water, or with a surface area
at high water line in excess of 20 acres or if the height of the dam will exceed 10 feet
measured vertically from the elevation of the lowest point of the natural surface of the
ground, where that point occurs along the longitudinal centerline of the dam, up to
the flowline crest of the spillway shall meet the requirements of Section 37 -87 -105
of the Colorado Revised Statutes and be approved for construction by the State
Engineer.
The responsibility for filing plans and specifications with the State Engineer shall rest
with the developer or his engineer. Adequate time shall be allowed for the review
process to take place. City approval of the detention facility is contingent upon
approval by the State Engineer.
Certification that the dam was constructed in accordance with approved plans and
specifications shall be provided to the City by a qualified Geotechnical Engineer upon
completion of construction. The cost of this certification shall be borne by the
developer.
C. Emergency Spillway
Unless otherwise approved, all dams shall be constructed with an emergency spillway,
designed to pass at least the 100 -year design flow without damage to the dam
assuming the outlet is completely plugged.
The Engineer shall analyze the emergency flow path back to the natural drainage way
and delineate on the subdivision plat any drainage easements required.
Complete documentation of spillway design, dam protection and emergency flow path
analysis shall be included in the drainage report.
D. Grading Requirements
Slopes on earthen embankments shall not be steeper than 4 (horizontal) to 1 (vertical).
All earthen slopes shall be covered with a minimum of 6" of native top soil and
revegetated with native grass.
28
Slopes on riprapped earthen embankments shall not be steeper than 2 (horizontal) to
I (vertical).
For natural grassed detention facilities the minimum bottom slope shall be 1.0% and
for bluegrass areas requiring maintenance the minimum bottom slope shall be 2.0%,
each being measured perpendicular to the trickle channel. For parking lot detention,
the maximum bottom slope shall be 4.0
E. Depth Requirements for Parking Lot Detention
The maximum depth for parking lot detention shall be 6" for the 10-year design and
18" for the 100 -year design.
F. Freeboard Requirements
The minimum required freeboard for detention ponds shall be 1.0 feet, except for
parking lot detention which shall be 6" above the computed 100 -year water surface
elevation.
G. Vegetation Requirements
An open space detention ponds shall be revegetated by either irrigated sod or natural
dry-land grasses in accordance with Guidelines for Development and Maintenance
of Natural Vegetation by Donald H. Godi & Associates, Inc., July 23, 1984, available
through the UD &FCD.
H. Trickle Flow Channel
All grassed detention ponds shall include a concrete trickle channel meeting the
requirement of Appendices A -27 and A -28.
I. Roadway Embankment Protection
Whenever a detention pond uses a roadway embankment to contain stormwater, the
embankment shall be protected from catastrophic failure due to overtopping.
Overtopping can occur when the pond outlets become obstructed or when a larger
than 100 -year storm occurs. Failure protection for the embankment may be provided
in the form of a buried heavy riprap layer (Type H) on the entire downstream face of
the embankment or a separate emergency spillway having a minimum capacity of
twice the maximum release rate for the 100 -year storm. Structures shall not be
permitted in the path of the emergency spillway or overflow. The invert of the
emergency spillway should be set equal to or above the 100 -year water surface
elevation.
Outlet Configurations
Presented in Appendices A -29, A -30 and A -31 are four examples of detention pond
outlet designs.
A Type 1 outlet consists of a grated drop inlet, outlet pipe and an overflow weir in the
pond embankment. The control for the 10 -year discharge shall be at the throat of
29
the outlet pipe under the head of water as defined on Appendix A -29. The grate must
be designed to pass the 10- year flow with a minimum 50 percent blockage (i.e., twice
the 10 -year flow). Since the minimum size of the outlet pipe is 18 inches, a control
orifice plate at the entrance of the pipe may be required to control the discharge of
the design flow. The difference between the 100 -year and 10 -year discharge is
released by the overflow weir or spillway. The surcharge on the 10-year outlet pipe
shall be included in the total discharge when sizing the overflow weir or spillway. If
sufficient pond depth is available, the drop inlet and the grate can be replaced by a
depressed inlet with a headwall and trashrack. Depression of the inlet is required to
reduce nuisance backup of flow into the pond during trickle flows. The maximum
trashrack opening dimension shall be at least equal to the minimum opening in the
orifice plate.
A Type 2 outlet consists of a grated drop inlet with an orifice controlled side inlet
covered by a trashrack and an outlet pipe. As shown on Appendix A -29, the control
for the 10 -year discharge occurs at the side orifice opening for the 10 -year headwater,
and the control for the 100 -year discharge occurs at the throat of the outlet pipe for
the 100 -year headwater. The difference between the 100 -year discharge and the 10-
year discharge passes through the top grate. To insure the 100 -year control occurs
at the throat of the outlet pipe, a grate designed to pass twice the flow difference is
recommended. In addition, the outlet pipe must have an adequate slope to insure
throat control in the pipe.
A Type 3 outlet shown on Appendix A -30 is similar to the Type 2 outlet except the
tmshrack covers the entire outlet works and the top grate can be eliminated. The 10-
year and 100 -year discharge control points are the same as the control points for the
Type 2 outlet.
A Type 4 inlet shown on Appendix A -31 is designed for use with parking lot
detention. The inlet consists of a weir curb opening for 10 -year flow control and a
weir overflow section for a 100 -year flow control. The outlet channel shall be
riprapped to prevent erosion of the berms and undermining of the curb and asphalt
parking lot.
Other outlet configurations may be acceptable upon approval by the City.
K. Outlet Design - Weir and Orifice Flow Calculation
1. Horizontal Crested Weirs:
The general form of the equation for horizontal crested weirs is:
Q = CLH"
iii,
where Q = Weir flow discharge (cfs)
C = Weir flow coefficients
L = Length of the weir (feet)
(For circular riser pipes, L is the pipe circumference)
H = Depth of flow over the weir (feet)
See Appendix A -32 for acceptable C values.
2. V- notched Weirs:
The general form of the equation for V- notched weirs is:
Q = 2.5 tan ( R ) H 5n
where Q = Weir flow discharge (cfs)
R = Angle of the notch at apex (degrees)
H = Depth of flow over the weir (feet)
3. Orifice Flow:
The general form of the equation for orifice flow (under submerged
condition) is:
Q = C A 2gh
where Q = Weir flow discharge (cfs)
Cd Orifice coefficient (Use C for sharp edged orifices)
A = Orifice opening area (square feet)
g = Acceleration of gravity = 32.2 (ft/sec)
h = Head above the centerline of the orifice (feet)
L. Maintenance and Inspection
All drainage reports which include detention pond designs must include a maintenance
and inspection report form to be used by the owner in performing annual maintenance
and inspections after storm runoff An inspection check list SF -2 is provided as a
guide for performing inspections and maintenance.
31
M. Water Quality Treatment Ponds
Where required by City Ordinance 124- 7(JXSxc) to provide special measures and
facilities with respect to any stormwater discharge from land associated with industrial
activity or from sites upon which industrial activities with a potential for release for
hazardous substances had been conducted in the past, water quality treatment ponds
and other "best management practices (BMPs)" may be used to reduce pollution in
stormwater runoff to the maximum extent practicable (see 40 CFR 122.26 and
Colorado Water Quality Control Act 25 -8 -101). Water quality treatment ponds shall
be designed in accordance with criteria and procedures contained in USDCM,
Volume 3 . Complete documentation shall be included in the drainage report.
4.4 Erosion Control Plan
4.4.1 General Requirements
The erosion control plan shall consist of acceptable erosion control practices and sediment trapping
facilities in conjunction with an appropriate schedule in order to accomplish adequate control.
Adequate erosion control measures shall be constructed prior to land disturbing activities such that
no adverse affects of site alteration will impact surrounding properties. Particular attention shall be
given to concentrated flows of water, either to prevent their occurrence or to provide appropriate
conveyance devices to prevent erosion. Sediment trapping devices shall be required at all points
where sediment laden water might leave the site. The plan must include permanent structures for
conveying storm runofl� final site stabilization, temporary sediment control features including
sediment basins and stabilization of the sites where temporary features have been removed.
Any erosion control measures to be done outside of the property line of the site will generally not be
approved unless the plan is accompanied by an appropriate legal easement of the area in which such
work is to be done.
Unless otherwise approved, 1 " = 50' or larger scale, shall be used for the erosion control plan. The
contour interval for these plans shall be two feet or closer, unless slopes exceed 10 where 10'
contour intervals are acceptable.
All construction activities disturbing more than 5 acres will require an NPDES permit issued by the
Colorado Department of Health, Water Quality Control Division, Permits and Enforcement Section.
The stormwater management plan must be reviewed by the City of Pueblo, Department of Public
Works.
Methods for determining erosion control measures for construction activities can be found in
USDCM. Volume 3
32
4.4.2 Required Information
The erosion control plan shall provide the following information for the entire tract of land to be
disturbed, whether or not the tract will be developed in stages. The plan shall contain:
A. A brief description of the project location including township, range, section and
quarter- section and the nature and purpose of the land disturbing activities, the total
area of the site and the area of disturbance involved.
B. A brief discussion of the existing site condition, including topography, vegetation, soil
types, drainage pattern and any wetlands on the site.
C. A vicinity map indicating the proposed development in relationship to roadway,
jurisdictional boundaries, and streams.
D. A site plan showing property boundary, features of the proposed development,
existing and proposed contours, existing and proposed water courses, critical erosion
areas, and any adjacent existing and proposed development that might be affected.
E. A discussion of temporary and permanent vegetative and structural practices which
specify the conservation measures to be used during all phases of clearing, grading,
filling, construction and permanent stabilization.
F. Plates and drawings showing details of erosion control measures utilized. Refer to
USDCK Volume 3
G. Calculations for designing control devices such as sediment basins, diversion ditches,
etc.
H. A schedule of anticipated starting and completion dates for each sequence and stage
of land disturbing activities depicting conservation measures anticipated, including
the expected date on which the final stabilization will be completed.
I. A schedule of regular inspections and maintenance on control facilities during
construction, including control structure repair and sediment basin cleaning, etc. per
NPDES permit requirements.
J. Documentation on design criteria used for riprap installations.
Additional information may be required by the City depending upon specific site considerations.
4.4.3 Plan Implementation
No clearing, grading, excavation, filling or other land disturbing activities shall be permitted until the
City approves the erosion control plan. After the plan is approved, proposed conservation measures
MI
must be installed before land disturbing activities are implemented. These conservation measures shall
apply to all on -site features, as well as to the protection of individual lots. During all phases of
construction, it shall be the responsibility of those who initiate such land disturbing activities to
maintain all erosion control features in a functional manner.
4.5 Easement Requirements
A Single Line Storm Sewers
For a single line storm sewer the easement width shall be:
W = B + 2H + 3
where W = Required easement width (feet)
B = outside span of pipe (feet)
H = Depth from top of pipe to final surface elevation (feet)
W shall be rounded to the next five foot increment with a minimum width of 20 feet.
The sewer shall be placed at the center of the easement. Access to easements shall
remain open with no fences, unless otherwise approved.
B. Multiple Line Storm Sewer
The width shall be calculated as a special case approved by the City.
C. Open Channels and Swales
Appendix A -33 shows the minimum easement as required to contain flood flows,
freeboard, and associated facilities plus a 12' wide vehicular access adjacent to the
channel. A 12' wide access easement to the nearest ROW must also be provided.
Lessor easement widths may be allowed for small channels and swales when it can be
shown that adequate maintenance access is provided.
D. Detention Ponds
As required to contain storage, freeboard, and associated facilities plus 12' wide
vehicular access around perimeter and to the nearest public ROW. Easements shall
also be provided for potential emergency spillway discharge, to the receiving drainage
easement or ROW. Acceptable alternatives will be considered if adequate facility
maintenance can be provided.
34
4.6 Water Quality
Special measures and/or facilities shall be provided with respect to storm water discharge from
any land associated with industrial activity or from sites upon which industrial activities or
other activities with a potential for release of hazardous substances had been conducted in the
past. Such special measures and facilities shall be designed to insure the following:
A. That the discharge of any pollutants in stormwater discharge will be reduced to the
maximum extent practicable.
B. That the stormwater discharge will comply with any state, federal or local effluent
limitations applicable to stormwater discharges.
C. That any spill of hazardous substances or toxic material will be contained to avoid
entry into any municipal stormwater facilities.
D. That there will not be a release or threatened release of hazardous substances or
hazardous wastes; and
E. That stormwater will not be discharged into municipal facilities which may cause or
contribute to a violation of a water quality standard.
35
LIST OF REFERENCES
Urban Storm Drainage Criteria Manual {USDCM). Volumes 1. 2 and 3, UD &FCD, March,
1969, revised May, 1984.
2. Procedures for Determining; Peak Flows in Colorado. SCS, March, 1984.
3. Roadwgy Design Manual CDOT, 1990.
4. Hydraulic Design of Highway Culverts, HDS No.5, USDOT, September, 1985.
5. Soil Survey of the Pueblo Area. Colorado, USDA, SCS, June, 1979.
6. Guidelines for Development and Maintenance of Natural Vegetation. Donald H. Godi &
Associates, Inc., July, 1984.
36
LIST OF ABBREVIATIONS
AASHTO :
American Association of State Highway and Transportation Officials
AVC :
Arkansas Valley Conduit
BMPs :
Best Management Practices
CBD :
Central Business District
CDOT :
Colorado Department of Transportation
cfs :
Cubic Feet Per Second
CSP :
Corrugated Steel Pipe
CUHP :
Colorado Urban Hydrograph Procedure
ft/sec':
Feet Per Second Per Second
fps :
Feet Per Second
HDS :
Hydraulic Design Series
NPDES :
National Pollutant Discharge Elimination System
RCP:
Reinforced Concrete Pipe
ROW:
Right- Of-Way
SCS :
Soil Conservation Service
SPP :
Structural Plate Pipe
TR -55 :
Technique Report No. 55
UD &FCD :
Urban Drainage and Flood Control District
USDA:
United States Department of Agriculture
USDOT :
United States Department of Transportation
USGS :
United States Geologic Survey
USDCM :
Urban Storm Drainage Criteria Manual
37
TIME - INTENSITY- FREQUENCY CURVES
:.
7.0
= 6.0
O.
O 5.0
Z
V
C
v
4.0
U)
Z
W 3.0
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J
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I
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STORM DURATION OR TIME OF
CONCENTRATION t (MINUTES)
CITY OF PUEBLO, COLORADO
STORM DRAINAGE DESIGN CRITERIA
a
i
I
100 -YEAR
25 -YEAR
10 -YEAR
5 -YEAR
DATE: 6/97
SHT. NO.: A -1
oll i v il = I 1 101 [WAREA 1 0 1 1 1 1"A
� 1
DURATION
DURATION
FACTORS
5 MIN.
0.29
10 MIN.
0.45
15 MIN.
0.57
30 MIN.
0.79
60 MIN.
1.00
DEPTH
INTEN
DEPTH
INTEN
DEPTH
INTEN
DEPTH
INTEN.
DEPTH
INTEN
FREQUENCY
!N.
IN /HR
IN.
IN /HR
IN.
IN /HR
IN.
IN /HR
IN.
IN /HR
5 YEAR
0.44
5.28
0.68
4.08
0.86
3.44
1.19
2.38
1.50
1.50
10 YEAR
0.50
6.00
0.78
4.68
0.99
3.96
1.37
2.74
1.73
1.73
25 YEAR
0.60
7.20
1.00
6.00
1.20
4.80
1.62
3.24
2.23
2.23
100 YEAR
0.77
9.24
1.20
7.20
1.52
6.08
2.11
4.22
2.67
2.67
NOTE: DEPTH OF EACH DURATION = ONE HOUR RAINFALL DEPTH X RESPECTIVE
DURATION FACTOR.
RAINFALL INTENSITIES FOR RATIONAL FORMULA APPLICATION
CITY OF PUEBLO, COLORADO I DATE: 6/97
STORM DRAINAGE DESIGN CRITERIA ISHT. NO.: A -2
INCREMENTAL RAINFALL DEPTH /RETURN PERIOD
CUHP or TR20 (Urban) Applications
I F COLORADO
STORM DRAINAGE DESIGN CRITERIA I SHT. NO.: A-3
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STORM DRAINAGE DESIGN CRITERIA I SHT. NO.: A-3
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CITY OF PUEBLO. COLORADO i Ur a Nyydvbwtor bd DATE: 6/97
STORM DRAINAGE DESIGN CRITERIA Fla 32 RUNOFF ISHT. NO.: A -5
RECOMMENDED RUNOFF COEFFICIENTS AND
PERCENT IMPERVIOUSNESS
LAND USE OR
PERCENT
FREQUENCY
SURFACE CHARACTERISTICS IMPERVIOUSNESS
2
5
10
100
Business:
Commercial Areas
95
.87
.87
.88
.89
Neighborhood Areas
70
.60
.65
.70
.80
Residential:
Single - Family
45
.40
.45
.50
.60
Multi -Unit (detached)
50
.45
.50
.60
.70
Multi -Unit (attached)
70
.60
.65
.70
.80
1/2 Acre Lot or Larger
30
.35
.35
.40
.60
Apartments
70
.65
.70
.70
.80
Industrial:
Light Areas
80
.71
.72
.76
.82
Heavy Areas
90
.80
.80
.85
.90
Parks, Cemeteries:
7
.10
.18
.25
.45
Playground:
13
.12
.18
.30
.50
Schools:
50
.45
.50
.60
.70
Railroad Yard Areas
20
.20
.25
.35
.45
Undeveloped Areas:
Historic Flow Analysis
2
(See
Lawns)
Greenbelts, Agricultural
Offsite Flow Analysis
45
.43
.47
.55
.65
(when land use not defined)
Streets:
Paved
100
.87
.88
.90
.93
Gravel (Packed)
40
.40
.45
.50
.60
Drive and Walks:
96
.87
.87
.88
.89
Roofs:
90
.80
.85
.90
.90
Lawns, Sandy Soil:
0
.00
.01
.05
.20
Lawns, Clayey Soil:
0
.05
.15
.25
.50
NOTE: These Rational Formula coefficients may not be
valid for
large basins.
CITY OF PUEBLO. COLORADO i MW Im DATE: 6/97
STORM DRAINAGE DESIGN CRITERIA TAKE 3-1 RLI OFF SHT. NO.: A -6'
NOMOGRAPH FOR FLOW IN TRIANGULAR GUTTERS I
1
From BPR st.OPt RATIO t, .No D[PT. j ,.(■
.01
I
CITY OF PUEBLO, COLORADO Us= M DATE: 6/97
STORM DRAINAGE DESIGN CR ITERIA Fla 6-1 STNS I SHT. NO.: A -7
2.0
a ,
1
000
n IS ROWNR[ss COEFFICI[ «T I. Y..«I ■8
.10
foaYYlA APPROPRIATC TO WATa VIAL
I N
� D00
WV
OOTTON Of CNA«■al,
300
a Is acGPaOCAL or CROSS SLOP[
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DOO
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.07
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D00
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70
EXAMPLE jut oaswas u■ast
05
U.
300
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so
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-_
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: _ _
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2
INSTRUCTIONS
DO
I
J
.01
p
oT
W
d
I..COrr[CT a/n RATIO WITH S LOPE ISI
Q
.03
. «o co. ■ECT one ■. +sc lol PIT.
=
O3
.006
M
DO
O[PT. 1,) T.(St TWO LINES MUST
U
_
2
Q
fNTt. U
S[CT AT TRN I +a LIN( FO.
(n
.0
'007
1r/ �
V
• 10
COYPL[TE SO.UTI
Q
.01
/1
.006
W
�./
a.
w
.oe
a. FOR SHALLOW
10
r - S-0to C..NNtI
'
.005
W
.07
D
O
AS s.OW. use .oYOfRAPH
.004
O
YLT : . Y
.06
W
p
C.
.05
D
TO
0
•003
a one .rlrc
m
p
CH "A.[[ 0 IN
N
04
PORTION OF CHANNEL 1
.AVINR 0101. E'
D
OETERNINE O[F J FOR TOTAL DI S CHAR GE
'.
.002
tNTIRE SECTION O THEN VIE NONOG +APH
To
.03
D
O[T[NNINE O 'N S(CTIO. b FOR OE ►TN
i
• TO O[T(.YIN( DISGH•+GE
^J
I« 1
' -•
""
Q.
.02
cor.osnE accT�o. - a
FOLLOW I.ST +uC. 7
1
Q
,o of T.I« 01 C..Rst I. lr.._
'001
HC „ o« o AT As Surto E�IJ -J 1
OtP J ; 08 O FOR
From BPR st.OPt RATIO t, .No D[PT. j ,.(■
.01
I
CITY OF PUEBLO, COLORADO Us= M DATE: 6/97
STORM DRAINAGE DESIGN CR ITERIA Fla 6-1 STNS I SHT. NO.: A -7
REDUCTION
FACTOR FOR
ALLOWABLE GUTTER CAPACITY
LOCAL AND
COLLECTOR STREETS
1.0
.9
s=
6%
F
.8
\
.7
\
INIT AL T ❑R
LL
\
s
"
O
H
U
MAJ R S ❑RM
La .5
0
V 4
0
W
cc
I
I
3
(
S 7
2
I
�
1
0
0 2 4 6 8 10 12 14
SLOPE OF GUTTER (°16), S
APPLY REDUCTION FACTOR FOR APPLICABLE SLOPE TO THE THEORETICAL GUTTER
CAPACITY TO OBTAIN ALLOWABLE GUTTER CAPACITY APPROACHING NON— ARTERIAL STREET
CITY OF PUEBLO, COLORADO
Reference: USDCM Fig 6 -2 Streets
I SHT.
DATE: 697
NO.: A -8
STORM DRAINAGE DESIGN CRITERIA
s=
6%
8
\
\
\
I
I
(
I
�
I
REDUCTION FACTOR FOR ALLOWABLE GUTTER CAPACITY
WHEN APPROACHING ARTERIAL STREET
V
LL. .7
•
0
.6
Z .5
0
O
4
w
cr
.3
V,
a
SLOPE OF GUTTER M
APPLY REDUCTION FACTOR FOR APPLICABLE SLOPE TO THE THEORETICAL GUTTER
CAPACITY TO OBTAIN ALLOWABLE GUTTER CAPACITY APPROACHING ARTERIAL STREET
USDCM Figure 8-2: Streets
CITY OF PUEBLO, COLORADO F&FEFeM Lg= go LDATE: 6/97
STORM DRAINAGE DESIGN CRITERIA FIR 6-2 SIRMI SHT. NO.: A-9
F=0
8
I \j
i
I
I
\
�
I � f
1
t t
S=6.4
F=0.5
M A40R
TOR
B�LOW MIN
A�LO BLE
W
STREE� GRADE
MUM
2 4
6 a 10 12 14
SLOPE OF GUTTER M
APPLY REDUCTION FACTOR FOR APPLICABLE SLOPE TO THE THEORETICAL GUTTER
CAPACITY TO OBTAIN ALLOWABLE GUTTER CAPACITY APPROACHING ARTERIAL STREET
USDCM Figure 8-2: Streets
CITY OF PUEBLO, COLORADO F&FEFeM Lg= go LDATE: 6/97
STORM DRAINAGE DESIGN CRITERIA FIR 6-2 SIRMI SHT. NO.: A-9
STREE R.O.W.
allowable gutter water surfaces at allowable g0 ter
flow depth capacity (symmetrical streetsection)
(symmetrical
street section) V
(a) SYMMETRICAL STREET SECTION
STREET R.O.W.
water urfoce of reduced allowable water surfaces at all
gutter opacity (non - symmetrical capacity (symmetrical
street ection)
reduced
allowable gutter allowable gutter
flow depth (non- flow depth
symmetrical (symmetrical
street section) street section)
gutter
section)
(b) NON- SYMMETRICAL STREET SECTION 1
STREET R.O.W.
Jwater surfaces at allowable gutter
capacity (symmetrical street secti(
r allowable gutter allowable gutter
flow depth (non- flow depth
symmetrical (symmetrical
street section) street section)
i
(c) NON- SYMMETRICAL STREET SECTION II
Note: For non - symmetrical street section, adjust the total gutter capacity by reducing the
allowable gutter capacity for the gutter with the higher flowline or for the entire
section when property line slopes ore different.
CITY OF PUEBLO, COLORADO DATE: 6/97
STORM DRAINAGE DESIGN CRITERIA SHT. NO.: A -10
TYPE "s" INLET DETAILS
6 5 .
rm ;�
: Hag
jo u �o
O 10 W
zo -zoo
r a
zc YEon
n�
Q�
-
9
O
a
�a
,
SC�
xax
� W ��j'1ZQQZ
_9 C
Q
�I
U
6 �
O
4
_sz
1 > Y W
S "
l _
U
Sg �
<
?x<
a =
r x J
x "�
X J J
X
O
O
a
t �
u
c o
o
= e
`I O
o <
i p
O
L
z �G
g SS
N .. W
x vd
i W �
< �J
n
Y
� y
Y
Ofi'O zJ
W C uw
;_
Ol
G <
u �+
x
zoo
�NO
C W W
1 II
Y
Z 2 2
2 O
J O ` Z Z O Z W a O In
< (..� < {� O .4 OJ7 Z
C o
J CC ` J � J <�i �i
<
ZA
Z 7 O< W Z U U� 0 Z � m — <
J Z N r W
OW 00 t- W
�
25
Z mml� V OK 2m N <O �-+ < W O
a O Z m O UK 2. 1� OO � W N� <� w OC O K N K
n ZZ o J�cv+u T S < � xx i3 s �3ac�"� { � y, ?om�il a lo� a C W ZOa
N <� V <�F WJJ OZZ W a W 27F� U� 2~
CZZJ< 0O ;; O <._.1J Z aW tqf� <�- a � W F �
NO�a W =<�`IZ�aJ�O�O`W1'
Ca _
2 N
CITY OF PUEBLO, COLORADO
STORM DRAINAGE DESIGN CRITE
s
.i ag x
�s
x
x<
A
<U
e
< pp C
2•
� c
O m
W q
C W
0 0
0
J
y
�4
U
W
a > z
U�m
W x0
2
=�a
o <Jo
mo o'
4 4
QrG
<pj <
csiW 1
ni \� �i
0
z
z z
5
II
i 553.^ = s .9•.0 ..9
DATE: 6/y f
SHT. NO.: A — II
r
TYPE "w" INLET DETAILS
1
► ' Y m 4s
0
1 ►• � 4► � � � �' 4 4� v
L
►
4 -
i�
i 5 'Fj
lit
i
T+� 11,1 ��► R <
N
l► y� W d' U
Z? ci z W
dc�Sao
z
JJJJJ - _
. I JJJJJ L � , •.
sip m o er F • r � = O �
uj
` I ( 'JJ_ (I+ I _ J J Vi m• D �r `` O W X x� V� v J
X1 1 �� : O � 0 1 W O W W Cj c 00
V 7 O
N Q = m g! r-
° i • 1 = U Z� C
+ F BF • � a - RT m J
CITY OF PUEBLO, COLORADO DATE: 6/97 _
STORM DRAINAGE DESIGN CRITERIA SHT. NO.: A -12
B
4' -3 1 /4'
GUTTER PAN ---- }� — 3'- 10
I 1 3' -3 s/a'
M ��1�
WEIM�
I
0 + •�\
w
115" MI . • GROUTED SLOPE °
TO PIPE
OUTLET
•
8 "
SECTION A- A (�
4' GUTTER PAN SCALE: 1" = 2' -0"
2 9 .�4 "
22 Y8 "�
A f I
z
0
a
o � �
N
3/4 "x1' -0" ® 12" SMOOTH
DOWELS W /APPROVED METAL
EXPANSION CAPS AS SHOWN
EXPANSION JOINT
•
SEE DETAIL
COLD JOINT
# 4 REBAR
10" O.C. E.W. (TYP.)
DETAIL
COLD ;CIN- SCALE: 1'' = ''-0
DEPARTMENT OF PUBLIC WOR -3
x REBAR Q CITY OF ENGINEERING DIVISION
).C. E.W. (TYP.) �p 211 East •D• St. 61008
TED SLOPE COLORADO 1719) 349 - 2660
IPE FAX 642 -6244
GRATED INLET
TYPE 13 (SINGLE)
Drawn By' A.C.M. DateiDEC - 1996 SNEET A -U
fiLEk -NE s019 Checked Byi N. W I Approved BysR. P.M
SECTION B- B
SCALE: 1 " = 2' -0"
15" MIN.
OU LET
�� C
�
COO CO CO�
N0. 13 GR & FRA
NEENAH R-3382
B
4 ' - 3 ' /i'
INLET
OPEN AREA EQUAL TO 233 SO. FT
SCALE: 1 " = 2' -0"
4' -3 1 /4'
GUTTER PAN ---- }� — 3'- 10
I 1 3' -3 s/a'
M ��1�
WEIM�
I
0 + •�\
w
115" MI . • GROUTED SLOPE °
TO PIPE
OUTLET
•
8 "
SECTION A- A (�
4' GUTTER PAN SCALE: 1" = 2' -0"
2 9 .�4 "
22 Y8 "�
A f I
z
0
a
o � �
N
3/4 "x1' -0" ® 12" SMOOTH
DOWELS W /APPROVED METAL
EXPANSION CAPS AS SHOWN
EXPANSION JOINT
•
SEE DETAIL
COLD JOINT
# 4 REBAR
10" O.C. E.W. (TYP.)
DETAIL
COLD ;CIN- SCALE: 1'' = ''-0
DEPARTMENT OF PUBLIC WOR -3
x REBAR Q CITY OF ENGINEERING DIVISION
).C. E.W. (TYP.) �p 211 East •D• St. 61008
TED SLOPE COLORADO 1719) 349 - 2660
IPE FAX 642 -6244
GRATED INLET
TYPE 13 (SINGLE)
Drawn By' A.C.M. DateiDEC - 1996 SNEET A -U
fiLEk -NE s019 Checked Byi N. W I Approved BysR. P.M
SECTION B- B
SCALE: 1 " = 2' -0"
CAPACITY OF GRATED INLET IN SUMP
t
w 0.6
w
0.5
cr
Li
> 0.4
0
0.7
EXAMPLE
a 0.3
w
0
0
? 0.2
0
z
0
•
•
FLOW INTO INLET PER SO. FT. OF OPEN AREA (CFS/FT
NOTE: Design Copocity = 50% Theoreticol Copocity
5
CITY OF PUEBLO, COLORADO FEFEFENCE I pip DATE: 6/97
STORM DRAINAGE DESIGN CRITERIA fld 4.1 STORM NETS SHT. NO.: A -14
NOMOGRAPH FOR CAPACITY OF CURB OPENING INLETS
IN SUMP. DEPRESSION DEPTH 2"
1.0 12 5
.9 11 1 8 4
3
10 6
.8 F- ►_
w
9 0 4 2
.7 3
�
8
2 �
.6 b
7 � p\e pot�- � .^
z 0 1.0
.5 g -- Exomple�Port o_ J I ' 0 z g
—.8- _. _ w
5.5 v -- -- _ a .8
f „ cn .6 O
U.
w 5 = z o 7
Z .4 F'
uu- .4 z
z 4.5 z a. 3 6
w
c w =
4 O .2 0 .5
0 = ►-
z z +-
c� o
w ' 3.5 w w �' 4
o a J 1
o w
w w LL 08 08 F.
.
25 3 ~o .06 .3
2 c� ° z_
= w a .04 m 25
2.5 w w
2 °- .03 Q
} 3
c 02 0 .2
CL
2 a z
� F-
a
.15 .01 15
L LL.
0
0
- -- - - - -- y0 c
1.5 <
a_2
.10
h
NOTE: Design Capacity = 80% Theoretical Capacity
CITY OF PUEBLO, COLORADO i tk9m DATE: 6/97
STORM DRAINAGE DESIGN CRITERIA F111 5 STOW KErS SHT. NO.: A -15 .
3.1
2.0
1.0
o.e
0.8
0.4
0.20
a
E 0.10
0 0.08
U
C�
0.06
0.04
0.02
0.01
E I LE N'
---- - - - - --
w a I ke k1k E
----- ---- --
==w==
mmmmwffi
MEN,
0 1 2
3
4
5 6 7 8 9
Cross
Slope,
Sx
(Percent)
REFERENCE:
Izzard, Carl. f., Report presented at the Annual Meeting of the National
Transportation Board, January 1977; Simplified Method For Design of Curb - opening Inlets
CITY OF PUEBLO, COLORADO DATE: 6/97
STORM DRAINAGE DESIGN CRITERIA I SHT. NO.: A -16b
Use of Fig. A- 16a & A- 16b
1. Enter with d at top. d is the depth of flow in the street section at a point
w ft. from the curb face.
d = S (T -2)
where S = street cross slope in feet per feet
T = flow spread in feet
2. Follow down to line for n. roughness coefficient. Use n = 0.017
3. Move (left or right) across to gutter slope, S.
4. Follow down to flow spread, T; this establishes a horizontal line.
5. If Qi and Q have been calculated and Li is to be determined:
multiply Qi by 1.25 to account for clogging, enter 1.25 Qi /Q (upper right)
and follow across to Limit line A, or line for S whichever is intersected first.
6. Move down to lower margin (Qi /Q = 0.1) and then diagonally to intersection
with line from Step 4.
7. Follow down to length of inlet, Li .
8. The horizontal line can be extended to line L for 100% interception,
then down to Li .
9. If length of inlet is given, enter with that length, move up to horizontal line
established in Step 4, diagonally to Qi /Q = 0.1, then vertically to S
(or line A) and across to Qi /Q. Reduce Qi by 80% to allow for clogging.
10. To obtain the increment of additional flow into the inlet due to the steepened
gutter cross slope, knowing S T and Q, go to figure A -16b and determine
p Qi /Q. Multiply this figure by Q to obtain the theoretical increment of
additional flow into the inlet. Reduce this figure by 80% to allow for clogging,
and odd to the inlet capacity, Qi .
CITY OF PUEBLO, COLORADO DATE: 6/97
STORM DRAINAGE DESIGN CRITERIA ISHT. NO.: A -16c
INLET CONTROL- CONDITIONS FOR CULVER
A
HW
ATER S URFACE
OUTLET UNSUBMERGED
B
WATER SURFACE
IiW - --- - - - -- -
OUTLET SUBM
INLET UNSUBM ERGED
C
WATER SURFACE
HW _
INLET SUBMERGED
MEDIAN DRAIN
Iq
WATER SURFACE
OUTLET SUBMERGED
� COLORADO
CITY OF PUEBLO,
' STORM DRAINAGE DESIGN CRITERIA
DATE 6/97
OUTLET CONTROL CONDITIONS FOR CULVERTS
WATER
SURFACE
HW
B
HW
A
HW
E
HW
\ I L - A. - S.
W.S.
H
-------------- - - --_- H W.S.
�-+► - ._.
CITY OF PUEBLO, COLORADO DATE: 6/9T
STORM DRAINAGE DESIGN CRITERIA SHT. NO.: A -18
INLET CONTROL NOMOGRAPH
HEADWATER DEPTH FOR CONCRETE PIPE CULVERTS
12
r
CITY OF PUEBLO, COLORADO USDC DF0OG Rnr *Z,08 DATE: 6/9T
STORM DRAINAGE DESIGN CRITERIA RQ 4-2 NETS d► CU.VBiT� I SHT. NO.: A -19
180
10,000
168
8,000 EXAMPLE
I (2)
( 3)
6.
156
6,000 0 -42 Inches (3.5 feat)
6.
5.000 0.120 cf a
5.
144
4,000 11 iv NM
6.
5.
132
D feet
4.
3,000 (1) 2.5 !.0
5'
4.
120
(2) 2.1 T.4
2,000 (3) 2.2 T.T
4 •
3
108
• 0 is feet
3 '
— 96
1.000
3 '
800
_
84
600
2
500
T2
400
2.
/
300
N
1.5
1.5
Z
to
50 v
200
1.5
Z
z
w
°
54
Q
f-
0:
W
G
100
J
48 /
Z
80
Q
=
v
=
/ r,
60 d
1.0
1.0
U.
2
o
w
SO HW ENTRANCE °
SCALE
40 p TYPE W
I.0
cc
ui
36
t
9
9
t—
w
30 (1) Sauero edge with
;
33
headwall
°
9
.�
a
20 (z) Groove end with w
G
30
headwall 2
•
.6
(3) Groove end
•�
2T
projecting
10
6
T
7-
24
T
6 To wee scale (2) or (3) Project
21
S horisentellf to $cote (1)
4 wee stralghllnclined line through
D end 0 scale$ or reverse es
itlwstreted,
3
6
. 6
.6
i8
2
IS
1 1.0
.S
. s
.s
12
r
CITY OF PUEBLO, COLORADO USDC DF0OG Rnr *Z,08 DATE: 6/9T
STORM DRAINAGE DESIGN CRITERIA RQ 4-2 NETS d► CU.VBiT� I SHT. NO.: A -19
OUTLET CONTROL NOMOGRAPH
HEADWATER DEPTH FOR CONCRETE PIPE CULVERTS
FLOWING FULL
r 2000
-
W Slope SC_. cs7l1
z SU6MERGEO OUTLET CULVERT FLOWIwG FULL
J
For outtll cm.a not wbmolget, Compute 14W by
mNlwh a.aaie.e w ttw f.sign pocoW.e
•
r�
O
i z
I to ti 0 0 i
W
z
� ° O a
5 f
t •,
•, 0
0 .a
.t.$
-.4
-.S
-.6
-.8
-1.0
-2
-3
-4
-S
-6
-8
-10
-20
CITY OF PUEBLO. COLORADO f Rift* Chwts for ft Oder W DATE: 6/97
STORM DRAINAGE DESIGN CRITERIA of H**.ay 0jvlfta m SHT. NO.: A -20
0
x
1000
z
5
f
800
120
600
108
S00
96
400
84
300
72
66
200
60
N
54
v
z
N
o•�e
48=
=
°
100
W
/Z
42
80%0
C
i
r
36
v
H
60
W
33
C'
—50
►-
W
30
40
Q
C
27
30
24
21
20
IB
10
IS
8
6
12
S
4
-
W Slope SC_. cs7l1
z SU6MERGEO OUTLET CULVERT FLOWIwG FULL
J
For outtll cm.a not wbmolget, Compute 14W by
mNlwh a.aaie.e w ttw f.sign pocoW.e
•
r�
O
i z
I to ti 0 0 i
W
z
� ° O a
5 f
t •,
•, 0
0 .a
.t.$
-.4
-.S
-.6
-.8
-1.0
-2
-3
-4
-S
-6
-8
-10
-20
CITY OF PUEBLO. COLORADO f Rift* Chwts for ft Oder W DATE: 6/97
STORM DRAINAGE DESIGN CRITERIA of H**.ay 0jvlfta m SHT. NO.: A -20
STORM SEWER ENERGY LOSS COEFFICIENT
(EXPANSION, CONTRACTION)
(a) Expansion (K e )
Q *
10
20
45
60
90
120
180
D
.3
D
0.11
0.40
0.86
1.02
1.06
1.04
1.00
12
D
0.11
0.40
1.06
1.21
1.14
1.01
1.00
a,
3
0
*The angle O is the
angle in degrees between
the sides of the
tapering section.
(c) Contractions (K c )
Z
O
0.1
0.4
0.6
0.8
1.0
K
0.5
0.4
0.3
0.1
0
Oj
EQUATIONS: 2
2 A
H = Ke 2'9 I — (Aj
2
A
2
N� = K� ( 2
2 1— ?
2q ( A, )]
(b) Pipe Entrance from Reservoir
Bell -mouth H - 0.04 V
29
Square -edge H = 0.5 V
29
Groove and U/S
For Concrete
Pipe H = 0.2 V
. 2'g
F - 1
CITY OF PUEBLO, COLORADO Reference: Linsley & Franzini, "Water DATE: 6/97
STORM DRAINAGE DESIGN CRITERIA Resources Engineering` SHT. NO.: A--21
McGraw -Hill, 1964
STORM SEWER ENERGY LOSS COEFFICIENT
(BENDS)
H 2 /1g)
CASE I
CONDUIT 6 90 CURVES*
NOTE: Head loss applied at F.C. for
length
RADIUS K
I X D 0.50
(2 to 8) X D 0.25
(8 to 20) X D 0.04
>20 X D 0
* When curves other than 90 are used,
apply the following factors to 90 curves
60 curve 85%
45 curve 70%
22 -1/2 curve 40%
CASE
BENDS WHEWFUDIUS IS
EQUAL TO DIAMETER OF PIPE
VOTE: Head loss applied at begining of
bend
6°BEND K�
90
0.50
60
0.43
45
0.35
22 -1/2
0.20
of
o
CITY OF PUEBLO, COLORADO Reference: APWA Special Report DATE: 6/97
STORM DRAINAGE DESIGN CRITERIA No. 49, 1981 I SHT. NO.: A -22
MANHOLE AND JUNCTION LOSSES
__ - -- __ 04L
O/
0 �
4.�
SECTION
CA_ SE 1
INLET ON MAIN LINE
a,ti
. SECTION
ASE M
,MANHi LE ON MAIN Lt_NE
WrrX 4S' BRANCH LATERAL
EQUATION:
V2 V
H = 2g — KI 2Q
V / ftAlt
y� 1 t1
0 ►,
SECTION
CASE II
INLET ON MAIN LINE
WITH BRANCH LATERAL
H .= 0 8. 11
PL AN
J�
SE CT K)4
CASE =
INLET OR MANHOLE AT
BEGINNING OF LINE
No Lateral 0.50
CITY OF PUEBLO, COLORADO Reference: APWA Special Report DATE: 6/97
STORM DRAINAGE DESIGN CRITE No . 49, 1981 1 SHT. NO.: A -23 '
NOT[ for A7 TIM
•1 W01.
CASE III
CASE N0. K�
8°
K�
I 0.50
22 -1/2
0.75
II 0.25
0
0.50
IV 1.25
60
0.35
90
0.25
No Lateral 0.50
CITY OF PUEBLO, COLORADO Reference: APWA Special Report DATE: 6/97
STORM DRAINAGE DESIGN CRITE No . 49, 1981 1 SHT. NO.: A -23 '
NOT[ for A7 TIM
•1 W01.
Minimum Pipe Diameter
Type
Main Trunk
Lateral from Inlet
18
15
1.77
1.23
eF Minimum size of lateral shall also be based upon a water surface inside the inlet or
minimum distance of I foot below the grate or throat.
Maximum Horizontal Distance
Vertical Dimension Maximum Allowable Distance
of Pipe Between Manholes and /or Cieanouts
(inches) (feet)
7
r,
Y7
a
m
.r
15 to 36 400
42 and Larger 500
Minimum Radius for Radius Pipe
Diameter of P
(inches)
Minimum Equivalent
Pie Diameter
(inches)
24 to 54
60 to 72
78 to 108
Minimum
Cross-Sectional Area
square f eel)
28.50
32.00
38.00
Short radius bends shall not be used on sewers 21 inch or less in
diameter.
CITY OF PUEBLO, COLORADO ROBENIX Canasta Pip DoWpn DATE: 6/97
STORM DRAINAGE DESIGN CRITERIA Mend, 1070 SHT. NO.: A -24
Radius of Curvature
(feet)
Cl
4 �
1
Z
Ui
O �
Z
w
w a: w H
U) C)
d-
w to
O U)
LL C Q
'z w
w
3 r
O
CCNCR` - _ CO_LA�
AS RZ.n
S =L T�' a STD V +
OR OWER ABOVE
4 3 COURSES Or BR CSC `-'IS E_E VAT 'ON
MINIMUM OR PRECAST 5' 4 0 5
SPACER RINGS \`
e 12" MIN cf)
P"PE AT M H SHALL BE CF THE
r
SAME CLASS AS PIPE IN LINE
SEE DETAIL
CONNECTION IF INFLOW PIPES 1 4AA0 a SPRiN
SHALL BE MADE WITH MINIMUM 6 ��Q LINE
Obix PROJECT iON INTO M H 'S
_ X
EPDXY GROUT -
(TYP ALL M H 'S)
zv_lz� PRECAST OR CAST - IN - PLACE
CONCRETE WALLS
�e
8'' MIN
6' -4" 48" STD.
TYP 7' -4" 60" STD.
8' - 4" 72" STD.
CLASS "B" BEDDING —�
SOLID CONCRETE TYPE II MANHOLE
BASE TO THIS ELEV.
IF CONTRACTOR
ELECTS TO MAKE
BASE IN ONE POUR
— UNDISTURBED EARTH FOR
CAST -IN -PLACE BASE OR
6" FLOWABLE FILL MATERIAL
FOR PRE -CAST BASE
TYPE 1A 48" STANDARD MANHOLE
B" THRU 15''
TYPE 1B 60" STANDARD MANHOLE
18'' THRU 36''
TYPE 1C 72" STANDARD MANHOLE
42'' THRU 48"
NO SCALE
DEPARTMENT OF PUBLIC WOR
CITY Of
ENGINEERING DIVISION
Rom 211 East 'D• $t. 81003
(719) 543 -2860
COLORADO FAX 542 -6244
RCP
3 SHALL
OUS CR
WITH 12'' LAP.
CONNECTION DETAIL
SCALE 1'' z2'0''
NOTES:
DESIGN CRITERIA
CONCRETE -4,000 P.S.I. COMPRESSIVE STRENGTH AT
28 DAYS (TYPE II -V CEMENT).
2 FOR PIPE INVERT ELEV.'S SEE PLAN & PROFILE SHEETS.
3 LADDER RUNGS REQUIRED IN ALL M.H.'S
4 IF ALTERNATE CSP DESIGN IS USED, TYPE II M.H. SHALL
BE MODIFIED & CONSTRUCTED FROM CORRUGATED PIPE,
5 IF PRE -CAST MANHOLE BASES ARE USED, THE CONCRETE
BENCH /TROUGH SHALL BE CAST -IN- PLACE.
FtsQ,W- SM
STANDARD FOR RCP
( SEE NOTE 4 )
NO SCALE
STORM MANHOLES
Drawn By'A C M. Oat* 'NOV -1995
SHEET A -25
Chocked By' N W . Approved ByiR.P M
MAXIMUM PERMISSIBLE VELOCITIES
FOR GRASS LINED CHANNELS
8
.J
7
J
O
s
a
i
ao
0
M
N
4
tp
r
U
Maximum Permissible Velocities For Earth Channels With Varied Grass Lining and Slopes
* For highly erodible soils, decrease permissible velocities by 25%.
Gross lined channels ore dependent upon assurances of continuous growth and
maintenance of gross.
CITY OF PUEBLO, COLORADO PreparW by: DATE: 6 /9T
STORM DRAINAGE DESIGN CRITERIA WRC Engineering, hr-, 1985 ISHT. NO.: A-2
V
Permissible
Channel Slope
Lining
Mean Flow Velocity*
(fps)
0 - 5%
Sodded Gross
7.0
Bermudogross
6.0
Reed Conarygross
5.0
Tall Fescue
5.0
Kentucky Bluegrass
5.0
Grass - Legume Mixture
4.0
Red Fescue
2.5
Redtop
2.5
Sericea Lespedezo
2.5
Annual Lespedezo
2.5
Small Groins (Temporary)
2.5
5 - 10%
Sodded Grass
6.0
Bermudogross
5.0
Reed Conorygross
4.0
Tali Fescue
4.0
Kentucky Bluegrass
4.0
Grass- Legume Mixture
3.0
> 10%
Sodded Grass
5.0
Bermudogross
4.0
Reed Conorygross
3.0
Tall Fescue
3.0
Kentucky Bluegrass
3.0
* For highly erodible soils, decrease permissible velocities by 25%.
Gross lined channels ore dependent upon assurances of continuous growth and
maintenance of gross.
CITY OF PUEBLO, COLORADO PreparW by: DATE: 6 /9T
STORM DRAINAGE DESIGN CRITERIA WRC Engineering, hr-, 1985 ISHT. NO.: A-2
V
J
T
TRICKLE CHANNEL DETAILS
RECTANGULAR CHANNEL SECTION
e -0' min.
1' 0' m il.
4 2 4'
For d > 6� .�' 6:6WWF W10iMo d s 6 min.
Opllonol cons }. ' • • •'..;•
Joint. t•
6' lorsr bid .
cowls moll. ' '
la
TRAPEZOIDAL CHANNEL SECTION
S top 6 1 6 WWF W 10 : W 10
la'min.
rr /dtpIh.
CITY OF PUEBLO, COLORADO
STORM DRAINAGE DESIGN CRITERIA
-0
1
I
i
2
s cool
18�
1
DATE: 6/97
SHT. NO.: A -27
TRICKLE CHANNEL DETAILS
COMBINATION CHANNEL SECTION
4'• 0 Tee.
K l� l
slam 9
rout roidt between rocks. — �oncrtto Rock
1
L A 4
�•
t 2�Ttn.
6 provol filter.
' CITY OF PUEBLO, COLORADO I DATE: 6/97
STORM DRAINAGE DESIGN CRITERIA I SHT. NO.: A -28
DETENTION POND OUTLET CONFIGURATION
Headwater for I foot Min. freeboard
weir flow
X7100 year water surface
Pond invert -,
(trickle channel)
Headwater fc
10 year flow
Grated inlet capacity -
greater than twice 10
year discharge
Overf low
spillway
Drop inlet
10 year control at throat of
outlet pipe, orifice plate may
be required
TYPE I OUTLET
No Scale
Headwater for foot Min fre
weir flow
q00 year water surface
ear water surface
Pond invert Orifice
(trickle channel) opening
Outlet 10 year capacity I
(18" o min.)
Grated inlet capacity
greater than twice 10
year discharge Top of Berm
Outlet pipe 100 year
— — — — — capacity (18" o min.)
Headwater for
!00 year flow
Slope
Headwater for-A LTrashrock"— 100 year control of throat of
10 year flow outlet pipe, orifice plate may
be required
TYPE 2 OUTLET
No Scale
Top of berm
!00 year overflow crest
Erosion protection
of D/S slope
Provide adequte pipe slope
to insure throat control
CITY OF PUEBLO, COLORADO Prepared by- DATE: 6/97
STORM DRAINAGE DESIGN CRITERIA WRC Wmeering. Inc.. 1986 SHT. NO.: A -29
DETENTION POND OUTLET CONFIGURATION
SECTION A -A
TOP OF BERM
! foot mli FREEBOARD
M04 YR W-
IV 1 A
TRASHRACK- --.�.. 100—YR CONTROL ORIFICE
10 TR K . S. ,.
T �
i !
10 -YR CONTROL WEIR (� A
OUTLET PIPE
100 year CAPACITY
O V )f min)
TYPE 3 OUTLET
NO SCALE
CITY OF PUEBLO, COLORADO pr,vu w DATE: 6/97
STORM DRAINAGE DESIGN CRITERIA WRC Engi weld , kr—, 1986 SHT. NO.: A -30
DETENTION POND OUTLET CONFIGURATION
f
j
. I
OVERFLOW CHANNEL
I
PARKING AREA��
PLAN
RIPRAP AND
0.5 foal m1a FRFLE9DARD • FILTER MATERIAL I
t�N
.ASPHALT
PARKING AR
I
CONCRETE C1lRB
*0 dCALIE -• . .
TYPE 4 OUTLET
CITY OF PUEBLO, COLORADO pwar b DATE: 6/97
STORM DRAINAGE DESIGN CRITERIA WRC Winwir9• kr- 1986 SHT. NO.: A -31
WEIR FLOW COEFFICIENT C
J
to
09
0.8
Q7
Q6
Q a5
0.4
Q3
Q2
Q1
0
SHAPE
`
'o
COEFFICIENT
COMMENT
A
�o�0 70
Sharp Crested With
N
n c
Ratio H 1 /P = 0.4
3.4
H
<
1.0
Ratio H 1/P = 2.0
4.0
H
>
1.0
Brood Crested With
w
Curves are based on fesls reporled
by Villemonle and ,Mavis
Sharp Upstream Comer
2.6
Minimum Value
Rounded Upstream Comer
3.1
Critical
Depth
Tr'"e Section
A) Vertical Upstream Slope With
�
1:1 Downstream
Slope
3.8
H
>
0.7
4:1 Downstreom
Slope
3.2
H
>
0.7
10:1 Downstream
Slope
2.9
H
>
0.7
B) 1:1 Upstream Slope
With
I:I Downstream
Slope
3.8
H
>
0.5
3:1 Downstream
Slope
3.5
H
>
0.5
Trapezoidal Section
1:1 Upstream Slope, 2:1
Downstream Slope
3.4
H
>
1.0
2:1 Upstream Slope, 2:1
Downstream Slope
3.4
H
>
1.0
Rood Crossings
Gravel
3.0
H
>
1.0
Paved
3.1
H
>
1.0
N � --- - --L
.
Submerged Weir
t
�i
0 at 0.2 0.3 Q4 as Q6 Q7 08 a9 to
H and
CITY OF PUEBLO, COLORADO F KNO 3 MATTE KANDWM DATE: 6/97
OF HYDF4LOGM
STORM DRAINAGE DESIGN CRITERIA "aw M Boot Cm iM ISHT. NO.: A -32
`
'o
A
�o�0 70
N
n c
O
Q- Discharge fa submerged �� N
condition in Cfs
Q- free discharge (H,, 0) in cfs ,
a
n - fxponen {in the free dschorge 1
e quation,
Q� • CH
w
Curves are based on fesls reporled
by Villemonle and ,Mavis
�
I
0 at 0.2 0.3 Q4 as Q6 Q7 08 a9 to
H and
CITY OF PUEBLO, COLORADO F KNO 3 MATTE KANDWM DATE: 6/97
OF HYDF4LOGM
STORM DRAINAGE DESIGN CRITERIA "aw M Boot Cm iM ISHT. NO.: A -32
TYPICAL GRASS LINED CHANNEL SECTION
Minimum Easement /R.O.W. Width
Maint.
Access Rd. 4
Notes:
Freeboard
Normal depth
4'
2% in. 2`.6
Channel side slope
Trickle Channel
1. Bottom Width: Consistent with maximum allowable depth and velocity
requirements, shall not be less than trickle channel width.
2. Trickle Channel: Minimum capacity to be 1% to 3% of 100 —year flow
but not less than 1 cfs. See Appendices A -27 and A -28 for
specifications.
3. Normal Depth: For grass lined channels, normal depth at 100 —year flow
shall not exceed 5 feet. Maximum 100 —year flow velocity at normal
depth shall meet velocity requirements specified in Appendix a -26.
4. Freeboard: Freeboard shall be provided in accordance with criteria in
Section 4.3.5.
5. Maintenance Access Road: Minimum width shall be 12 feet. All or
part of the road may be required to be surfaced.
6. Easement /Right of Way Width: Minimum width to contain flow,
freeboard and maintenance access road.
7. Channel Side Slope: Maximum side slope for grassed channel shall be
4:1.
CITY OF PUEBLO, COLORADO
STORM DRAINAGE DESIGN CRITERIA
DATE: 6/97
SHT. NO.: A -33
6x6 -W'. dxh' UtS'H
PLACED., AS S - OWN F 0W L.NE
2 Can 2 C R
e
� e
N
c�
I
DIP DETAIL
SCALE: 1'' = 2-0"
T CKtiScc _ i E
4 5° 4 �°
�J L2
TEMPLATE
SCALE 1'' = 2-0"
6" 24
1'' R 1/2'' R
�'
c D
N
'— • c0
f_
6x6— W1.4xW1.4 WIRE MESH
PLACED AS SHOWN
2'' CLR.
1
N
c�
0"
TO 2"R
/ 5 2
STANDARD CURB & GUTTER
SCALE: 1'' = 2' -0"
16" 14"
1/2" R� 12 .,
1/2'' R
N
• • .
30" _
RAMP CURB & GUTTER
SCALE: 1" = 2-0"
/ -ROUND -OFF SHARP CORNERS 6,.
5 ..
L
1/3h = C ?B
THICKNESS = 3/16''
HEAD HEiv�1'
• 2„ L
• 4 5°
2' -6" c� 45°
N
�.
ROLLED CURB & GUTTER TEMPLATE 6" CURB HEAD
SCALE = 2-0" SCALE: 1'' = 2' -0'' SCALE 1'' = 2-0"
d
V
FLOW LINE
CPTICNAL
S'LC°-'
1/2 ' /FT
NOTE:
S" THICK CONCRETE WITH POLYPROPYLEN
FIBER REINFORCING MAY BE SUBSTITUTE1
FOR 7'' REINF. CONCRETE.
° e
a
SLOPE 1/2'' PER FOOT
CURB & GUTTER TYPE 2
SECT 1-B
SCALE: 1'' = 1'-0"
FILENAME. 502
-0"
3' -0" OR 4' -0"
AS SHOWN ON PLAN
DOUBLE GUTTER
SCALE: 1'' = 2' -0"
DEPARTMENT OF PUBLIC WOR
CITY OF ENGINEERING DIVISION
p � 211 East •D• St. 81003
O
(710) 543 -2860
COLORADO FAX 542-6244
CONCRETE CURB & GUTTEF
DOUBLE GUTTER & DIP
Drawn ey' A , C . M . Dats' N OV -19 9 5 I 8N A-
EETi
Chocked By, N. W. I Apprond ey.R P, M
v
v
v
l <
17TH
Z; 0
14TH
13TH
SCALE: 1"=1000-
FRA I � - - I + � ' r
CISCO
LN
v
V OTH 1 I ST
'
v ST —
NI
6T)4 ST
V--
C;!
>
ST 3-L-
MInT Vk 3RD 3R ST
ST v T
1S ST 1ST i ST
�-Rp got ST
-
CENTRAL BUSINESS DISTRICT (CP-1)
I CITY OF PUEBLO,
COLORADO
DATE:
7/95
STORM DRAINAGE
T
DESIGN CRITERIA
S
SH T. NO.:
B -I.
Date of Submittal
CITY OF PUEBLO - PRELIMINARY DRAINAGE REPORT CHECKLIST
SUBDIVISION NAME:
--------------------------------------
Developer Name: Engineer's Name:
Address: Address:
Telephone: Telephone:
1. Drainage Report emplete N/A
a) Drainage report checklist signed by Engineer
b) Cover letter and certification by Engineer
c) Discussion of the following as they pertain to or are affected by the
proposed development :
- Major drainage basins and subbasins.
- Existing drainage studies and reports, master drainage plan.
- Upstream drainage considerations.
- Downstream drainage considerations.
- Onsite drainage considerations -flow arrows for lot drainage.
- Erosion control and water quality treatment.
- Existing floodplain information.
- Maintenance responsibilities of drainage facilities - maint. checklist.
2. Location Map
3. Drainage Plan (In folder pocket at the end of Drainage Report)
a) Title block.
b) Engineer's statement.
c) Overall drainage basin boundary and sub basin boundaries.
d) Existing and proposed contour at 2 ft. maximum intervals. In terrain
where slope exceeds 1(%, maximum interval is 10 ft.
e) Property lines and easements with purposes noted.
f) Streets and R.O.W. lines. Type of curbing, flow arrows.
g) Drainage patterns using flow.
h) Existing and proposed utilities.
I) Existing and proposed storm sewers.
j) Existing and proposed culverts.
k) Existing and proposed open channels.
1) Existing and proposed detention ponds. Delineate 100 -year ponding
inundation limits.
SF -1
m) Existing natural channels within 150 feet of project. Delineate 100 -year
floodplain (or erosion buffer zone if applicable. Show bridges, culverts
and erosion control features if any.
n) Irrigation ditches and canals.
4. Preliminary Erosion Control Plan
I hereby certify that the Preliminary drainage report contained herein was prepared under my direct
supervision and checked by me and that the above checklist accurately depicts the contents of this submittal.
Professional Engineer Date
P.E. Number
CITY STAFF REVIEWER:
DATE REVIEWED:
COMMENT
SF -1
Date of Submittal
CITY OF PUEBLO - FINAL DRAINAGE REPORT CHECKLIST
SUBDIVISION NAME:
--------------------------------------
Developer Name: Engineer's Name:
Address: Address:
Telephone: Telephone:
1. Drainage Report Complete N/A
a) Drainage report checklist signed by Engineer
b) Cover letter and certification by Engineer
c) Discussion of the following as they pertain to or are affected by the
proposed development:
- Major drainage basins and subbasins.
- Existing drainage studies and reports, master drainage plan.
- Upstream drainage considerations.
- Downstream drainage considerations.
- Onsite drainage considerations -flow arrows for lot drainage.
- Erosion control and water quality treatment.
- Existing floodplain information.
- Maintenance responsibilities of drainage facilities - maint. checklist.
2. Location Map
3. Drainage Plan (In folder pocket at the end of Drainage Report)
a) Title block.
b) Engineer's statement.
c) Overall drainage basin boundary and sub basin boundaries.
d) Existing and proposed contour at 2 ft. maximum intervals. In terrain
where slope exceeds 10 0 /6, maximum interval is 10 R.
e) Property lines and easements with purposes noted.
f) Streets and R.O.W. lines. Type of curbing, flow arrows.
g) Accumulation of flows (cfs) at design points. Show paths chosen for
computation of time of concentration.
h) Existing and proposed utilities, type and size.
i) Existing and proposed storm sewers, inlets and manholes. For storm
sewers show size, slope, material, flow rate and flow arrows. For inlet
show type and length. Show diameter of manholes.
J) Existing and proposed culverts. Show size, material and flow rate. Show
headwalls, wingwalls and erosion control details. Delineate 100 -year
ponding limits.
SF -la
k) Existing and proposed open channels. Show typical cross sections with
water surface elevations. Identify channel lining, slope, flow rate and
velocity, and details of erosion control features and trickle channel.
1) Existing and proposed detention ponds. Show grading plan, storage
volumes for 10- and 100 -year ponding elevations. Delineate 100 -year
ponding inundation limits. Show outlet structure, spillway, and trickle
channel details.
m) Existing natural channels with 150 feet of project. Delineate 100 -year
floodplain (or erosion buffer zone if applicable. Show bridges, culverts
and erosion control features if any.
n) Irrigation ditches and canals.
o) Professional Engineer's seal and signature on record copy.
4. Calculations verifying that the following drainage facilities are designed in
accordance with the City of Pueblo's storm drainage design criteria.
a) Streets
b) Storm inlets
c)
Culverts
d)
Storm Sewers
e)
Open Channels
f)
RIP RAP and Erosion Control Structures
g)
Stormwater Detention Facilities
h)
Water Quality Treatment Pond
5. Grading and Erosion Control Plan
I hereby certify that the final drainage report contained herein was prepared under my direct supervision and
checked by me and that the above checklist accurately depicts the contents of this submittal.
Professional Engineer Date
P.E. Number
CITY STAFF REVIEWER:
REVIEWED:
COMMENTS:
SF -la
INSPECTION REPORT FOR
RATER QUALITY AND STORMWATER DETENTION PONDS
Inspector: Date:
Date of Last Inspection: Date of Last Sediment Clean Out: _
Inspection Type: Scheduled Post -flood
If Post -flood inspection, was Emergency Spillway overtopped Yes No
SF -2
Pond Feature
Checked
Maintenance
Required
Comments/Action
Required
Olt }[ DR,4I 5 Otl LET PROT z ' .' "• , r .
T „1'+�.T�O:T•. r,�, .•wk,� '•i'.:,4`"'. r ae�,`' !'GF�'�r. 2✓ .. •;�� ^i,�.••v� oa
a) Pipe
b) Chancel
.,.,�•; •yrKt ,ear••• • +., .a ` ' •. ✓M' *',,a;aY`r. f �,,•�,,. ;,� ' , .•�'k =' ° a�" �:`� '` .: '., ' w.��
'UPPER STAGE { < + ��. • �'�w,�" ��x'��';,a Ra„�.,��` + � w . ' '�,,a., .;' c�s � � • ,g��y��� ; �'• ' �� <� •;.�` *;,';..�w,,; M1 ,.„raA
a) Low now Channel
WNVER STACEY
a) sediment bevel (1 foot maximum)
(1) Whit Volume of Sodimed Was Removed
b) Standing Water?
c) Sed'unent Level Delineator
OL'TIXT SMUCTME :a
a) Perforated Riser Pipe
b) Gravel Filter
C) Wet - (1) scwement
(2) Grate Condition
(3) Debris
d) Principal Spillway
e) Outlet Apron
E.NORdENCY SPILLWAY: .
a) Condition
DA.NI E;S BAN KMFtiT ..
a) Sewement
b) Erosion
C) Seepage
d) Seepage ® Principal Spillway
I1M)SCAP; N GF kTCRP4
a) Vegetation Condition (frees, Shrubs, Grasses)
b) Sprinkles System
c) Erasion
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CITY OF PUEBLO, COLORADO
DATE: 6/97
MINIMUM STORM DRAINAGE DESIGN CRITERIA I SF
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CITY OF PUEBLO, COLORADO
DATE: 6/97
MINIMUM STORM DRAINAGE DESIGN CRITERIA I SF
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MINIMUM STORM DRAINAGE DESIGN CRITERIA SF - 4
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CITY OF PUEBLO, COLORADO I DATE: 6/97
MINIMUM STORM DRAINAGE DESIGN CRITERIA I SF -11