Design and Construction of Urban Stormwater Management Systems - MOP FD-20

Chapter 1 Evolution of Urban Stormwater Management

1.     Introduction

2.     Need for the Manual

3.     Organization of the Manual

4.     The Intended Audience

5.     Themes and Principles that Drive the Design Effort

6.     Glossary

7.     References

Chapter 2     Financial, Legal, and Regulatory Concerns

1     Introduction

2     Financial
A. State and Federal Sources
1. U.S. Army Corps of Engineers (COE)
2. Soil Conservation Service (SCS)
3. Environmental Protection Agency (EPA)
4. Community Development Block Grant Program
5. Federal Emergency Management Agency (FEMA)
6. National Weather Service (NWS)
7. State Funds
B. Local Sources
1. General Tax Revenues
2. Dedicated Ad Valorem Taxes
3. Service Charges or Fees
4. Special Assessments
5. Bonds
6. Stormwater Utilities
7. Development Fees and Developer-Provided Facilities
8. Free-in Lieu of On-Site Detention/Retention
9. Plan Review and Inspection Fees
10. Dedications


3      Legal
A. General Rules of Law
C. Liability Issues
1. Ordinary and Extraordinary Floods
2. Public Liability
3. Other Liability Considerations
4. Limiting Liability


4      Regulatory Concerns
A. Floodplain Regulation
B. Section 404 Permits
D. Erosion Control, Stormwater Detention,
and Subdivision Ordinances and Codes


5     References

Chapter 3     Surveys and Investigations

1     Introduction

2     Definitions

3     Monitoring and Data Collection

4 Information Required for Design
A. Topographic Information
B. Survey and Boundary Data
C. Soils and Geologic Data
D. Hydrologic and Hydraulic Data
E. Regulatory Data

5     Financial Data

6     Data Management

7     References

Chapter 4     Design Concepts and Master Planning

1     Introduction

2     Principles

3     Drainage Systems
A. Natural Channels
B. Effects of Urbanization

4     Basic Conceptual Elements

5 Preventive and Corrective Actions
A. Preventive Actions
B. Delineation of Floodplains
C. Corrective Actions


6     Structural Components of Drainage Systems
A. Major Drainageways
B. Streets
C. Storm Sewers
D. Storm Inlets
E. Intersections
F. Flow Control Devices
G. Trash Racks (Safety Racks)
H. Detention Facilities
I. Water Quality Mitigation Measures (Other than Detention)
J. Other Special Structures


7     Risk Analyses
A. Definitions
B. Methodology


8     Design Economics

9     Drainage Master Planning

10     References

Chapter 5     Hydrology and Introduction to Water Quality

1     Introduction
A. Effect of Urbanization of Streamflows
B. Quality of Urban Runoff


2     Quantity of Stormwater
A. Overview
B. Design Points, Catchments, and Return Periods
C. Methods for Computing Stormwater Flows
D. Design Rainfall
1. Synthetic Design Storms
2. Rainfall Depth
3. Temporal Distribution
4. Spatial Distribution
5. Other Methods for Design Hydrology
E. Rainfall Abstractions
1. Interception
2. Infiltration
3. Green-Ampt Equation
4. Horton Equation
5. Soild Conservation Service Equation
6. Depression Storage
F. Runoff Hydrographs
1. Synthetic Unit Hydrograph
2. Time-Area Curves
3. Kinematic Wave
4. Nonlinear Reservoir
G. Rational Method for Peak Discharge
1. Limitations of the Rational Method
2. Runoff Coefficent
3. Rainfall Intensity
4. Time of Concentration
5. Contributing Area
H. Assessing the Reasonableness of Computed Flows
I. Interpretation of Computer Flows
J Significance of Historic Flood Data
3 Quality of Storm Sewer Discharges
A. Pollutant Sources: Non-Storm Water Sources
1. Illicit or Cross Connections
2. Interactions with Sewage Systems
3. Improper Disposal
4. Spills
5. Malfunctioning Septic Tanks
6. Infiltration of Contaminated Ground Water
B. Pollutant Sources: Runoff Related Sources
1. Runoff from Residential and Commercial Areas
2. Runoff from Construction Sites
3. Runoff from Industrial Lands
4. Runoff from Roads and Highways
5. Estimation of Pollutant Loads
C. Water Quality Impacts of Storm Water Discharges
1. Parameters Associated with Impacts
2. Assessing Impacts

4 References

Chapter 6:     Storm Drainage Hydraulics

1     Introduction

2     Flow Classification
A. Steady vs. Unsteady Flow
B. Uniform vs. Nonuniform Flow
C. Open Channel vs. Closed Conduit Flow
D. Laminar vs. Turbulent Flow
E. Subcritical vs. Supercritical Flow

3     Conservation of Mass

4     Conservation of Momentum

5     Conservation of Energy
A. Hydraulic and Energy Grade Lines
B. Specific Energy
C. Froude Number
D. Critical Depth

6     Normal Depth

7     Water Surface Profiles

8     Hydraulic Jump

9     Friction Losses
A. Hazen-Williams Formula
B. Darcy-Weisbach Equation
C. Manning Equation


10     Minor Losses
A. Transition Losses
B. Entrance Losses
C. Manhole and Junction Losses
D. Bend Losses

11     Calculation of Water Surface Profiles

12     Special Hydraulic Structures
A. Storm Sewer Inlets
B. Culverts
C. Energy Dissipators
D. Drop Structures
E. Outlet Structures


13     Routing
A. Types of Routing Methods
B. Detention Basin Routing by Modified Puls Method
1. Basic Equations
2. General Routing/Design Procedure for
Stormwater Detention Facilities
3. Multi-stage Detention Facilities

14     References

Chapter 7     Computer Modeling

1     Introduction

2     Problem Identification
A. Drainage and Flooding
B. Detention/Retention Storage
C. Sedimentation
D. Water Quality


3     Urban Modeling Objectives and Considerations
A. Planning, Analysis/Design and Operation
B. When Should a Model Be Used?


4     Model Definition 5     Overview of Available Modeling Options
A. Introduction
B. Continuous Versus Single-Event Simulation
C. Modeling Options
1. Constant Concentration or Unit Loads
2. Spreadsheets
3. Statistical Approaches
4. Regression - Rating Curve Approaches
5. Buildup and Washoff
6. Related Mechanisms

6     Computer Requirements

7     Steps in Modeling
A. Data Requirements
B. Basic Input Data
C. Rainfall Unit
D. Sensitivity Analysis
E. Calibration
F. Verification
G. Uncertainty Analysis
H. Production Runs


8     Models
A. Published Reviews
B. Models To Be Reviewed
1. DR3M-QUAL
2. HSPF
3. ILLUDAS
4. Penn State
5. Statistical
6. STORM
7. SWMM
8. TR55
9. HEC-1
10. HEC-2

9     Model Selection

10     Computer Aided Drafting and Design (CADD)

11     Summary

12     References

Chapter 8     Design of Drainage Conveyances

1     Introduction

2     Frequency of Design Runoff

3     Generalized Design Procedures
A. Preliminary Design
1. Define Project Goals and Objecives
2. Define Pertinent Regulations and Criteria
3. Collect Basic Data
4. Determine Limits of Basin and Analyze
Preliminary Data
5. Obtain Site Development Plan and Formulate
Conceptual Alternatives
6. Refine Conceptual Alternatives to
2-3 Preferred Strategies
7. Preliminary Design
8. Review Alternates and Formulate Preferred
Alternative for Final Design
B. Overview of Final Design
1. Review all Preliminary Work
2. Obtain Final Street Grades, Geometry,
Elevations, Etc.
3. Hydraulically Design the Open Channel and
Storm Sewer Systems
4. Complete all Other Aspects of the
Design Effort


4      System Layout
A. Location Requirements
1. Main Location
2. Alignment
3. Crossings
B. Manholes (Cleanout Structures)
C. Grade and Cover


5      Hydraulic Design of Storm Sewers
A. Design of Closed Conduits
1. Range of Applicability
2. Design Procedures
3. Losses at Manholes
B. Pressurized Storm Sewers
1. Basic Design Procedures
2. Allowable Pressures
3. Discharge Point
4. Within the System
5. Friction and Form Losses


6     Storm Sewer Inlets
A. Categories, Definitions, and Applications
B. Curb Opening Inlets
C. Grate Inlets
D. Curb and Grate (Combination) Inlets
E. Special Purpose Inlets
1. Bicycle-Safe Grates
2. Pipe Drop Inlets
3. Slotted Drain Jets
F. Inlet Design Criteria and Practices
G. Inlet Selection


7     Infiltration and Exfiltration
A. Deliberate Infiltration/Exfiltration
B. Inadvertent Infiltration/Exfiltration


8     Street and Intersection Design
A. Classification of Streets
B. Effect of Stormwater Runoff
on Street Traffic Capacity
C. Storm Drainage Design Criteria
for Urban Streets
1. General Guidance
2. Cross Fall
3. Street Capacity for Minor Storms
4. Street Capacity for the
Major System Design Runoff
5. Cross-Street Flow
6. Intersections
7. Special Considerations
D. Storm Drainage Design Criteria
for Rural Streets


9     Major Drainageways (Open Channels)
A. Choice of Channel
B. Hydraulic Analysis
1. Channel Geometry
2. Hydraulic Roughness Values and Loss Coefficients
3. Stage/Discharge Data
4. Data Sensitivity
C. Concrete-Lined Channels
1. Supercritical Flow
2. Subcritical Flow
D. Grass-Lined Artificial Channels
1. Channel Stability/Protection
2. Preliminary Design Criteria
3. Channel Cross-Sections
4. Freeboard
5. Curvature
6. Right-of-way Width
7. Roughness Coefficients
8. Erosion Control
9. Water Surface Profile
E. Natural and Composite Channels
F. Other Channels


10     Culverts and Bridges
A. Culverts
1. Culvert Hydraulics
2. Design Procedure and Example
3. Design Considerations
4. Debris/Safety Racks
B. Bridges
1. Types of Flow Through Bridges
2. Hydraulic Evaluation


11     Application of the Rational Method in Design

12     Economic Considerations
A. Economic Comparison of Alternatives
1. Procedures for Economic Evaluation
2. Capital Costs
3. Operation and Maintenance Costs
4. Replacement Costs
5. Material Service Life
6. Life Cycle Cost Analysis
7. Non-quantifiable Factors
B. Engineer's Estimate of Construction Cost

13     References

Chapter 9     Special Structures and Appurtenances

1     Introduction

2     Erosion and Scour
A. Determination of Scour Potential
1. Maximum Permissible Flow
Velocities - Unlined Channel
2. Retardance and Permissible
Velocities - Grassed Channels
3. Tractive Force
B. Channel Side Slopes
C. Local Scour
D. Structural Measures for Channel Protection


3     Erosion Protection Measures for Channels
A. Definitions, Categories, and Applications
1. Classification of Erosion Protection Measures
2. Flexible and Rigid Erosion Protection
3. Temporary and Permanent Erosion Protection
4. Vegetative Erosion Protection
5. Flow Duration
6. Permissible Shear Stress
B. Channel Bank and Bed Protection
1. Riprap
2. Gabions
3. Man-made Protection Materials
4. Common Channel Protection Measures
Other Than Riprap and Gabions
C. Riprap Protection at Outlets
1. Apron Dimensions
2. Apron Materials
4     Check Dams
A. Categories, Definitions, and Applications
B. Porous Check Dams
C. Impervious Check Dams
D. Check Dam Design Considerations


5     Energy Dissipators
A. Definitions, Applications, and Categories
B. Riprap Basins for Small Culvert Outlets
C. Stilling Basins
1. Design Considerations
2. Control of Jumps
3. Stilling Basin Categories
D. Simple Energy-Dissipating Headwalls
E. Design Criteria and Practices


6     Drop Structures
A. Categories, Definitions, and Applications
B. Open Channel Drops (Drop Spillways)
1. Straight Drop Structure
2. Box Inlet Drop Structure
C. Drop Shaft Structures
1. Completely Flooded Drop Shafts
2. Subatmospheric Drop Shafts
3. Spiral (Vortex) Drop Shafts
4. Design Considerations


7     Siphons
A. Definitions, Categories, and Applications
B. Single-Barrel Siphons
C. Multi-Barrel Siphons
D. Design Criteria and Practices


8 Side-Overflow Weirs
A. Definitions and Applications
B. Design Considerations
C. Design Practices
1. Falling Water Surface
2. Rising Water Surface


9 Flow Splitters, Junctions, Flap Gates, and Manholes
A. Flow Splitters
B. Junctions
C. Flap Gates
D. Manholes
1. Size
2. Frame and cover
3. Steps
4. Manholes on Pipes Flowing Full
5. Deep Manholes


10 Stormwater Pumping
A. Introduction
B. Planning and Site Considerations
C. Design Features
D. Storage
E. Pumps
1. Pump Types
2. Pump Selection


F. Mass Curve Routing

11     References

Chapter 10     Combined Sewer Systems

1     General Description of Combined Sewerage Systems
A. Introduction
B. Flow Regulation Devices
1. Purpose
2. Static Regulators
3. Dynamic Regulators
C. Overflows
1. Gravity Outfalls
2. Submerged Outfalls
D. Interceptors

2     Combined Sewer Overflow Pollution Loads

3     Methodology for Evaluating Combined Sewer Overflows
A. General
B. Data Collection
C. Field Investigations
1. Inspections of Physical Facilities
2. Flow Monitoring and Sampling
3. Receiving Water Sampling
D. Assessment of Existing and Future Land-Based Conditions
1. Population and Dry-weather Flows
2. Land Use and Zoning
E.
Definition of Receiving Water Issues and Goals


4     Combined Sewer Overflow Mitigation Techniques

A. General
B. Identification of Applicable CSO Mitigation Techniques
1. Source Controls
2. Collection System Controls
3. Off-line Storage and Treatment
C. Combined Sewer System Maintenance
1. Records
2. Regulators
D. Nonstructural Techniques
1. Land Use
2. Interceptor Sediment Removal
3. Regulator Mod