PRIORITIZING STORMWATER CAPITAL IMPROVEMENT PROGRAM (CIP) PROJECTS - - PowerPoint PPT Presentation

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PRIORITIZING STORMWATER CAPITAL IMPROVEMENT PROGRAM (CIP) PROJECTS

APWA Fall Joint Conference| Kearney, NE | November 6th , 2013

Presented by Lalit Jha, PE, D.WRE, CFM Miles Simmons, EIT, M.S.

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Agenda

• Urban Drainage Issues
• CIP Prioritization
• Study Methodology
• Project Benefits
• Conclusion

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Urban Drainage Issues

• Flooding Problems
• Structural Condition of the System
• System Upgrades and Master Planning
• Operation and Maintenance
• Stormwater Program Financing

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63rd and Fletcher Ave. 50th and R St.

Localized Flooding

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27th and Highway 2 33rd and Highway 2

Stormwater System Deficiencies

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14th and Holdrege St. 11th and Oak St.

Structural Condition

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Urban Drainage Issues

“How can drainage problems be identified?” “Which problems should be addressed first?” “What are the financing needs?”

“Most bang for the buck”

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Background – Lincoln, Nebraska

• State Capital, second largest City in NE
• Population 260,000
• 82 square miles within City limits
• 500 miles of public storm drain system
• 230 miles of open channel system
• 31,000 ancillary items

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Background – CIP Prioritization

• Previous methodology developed in 1966
• Based on out‐dated standards
• Reactive approach

“Squeaky wheel gets the grease”

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Project Objective

• Develop an updated prioritization

methodology and a proactive CIP

• Identify stormwater CIP projects
• Enhance the City’s stormwater database

“Reduce Flooding and Drainage Issues”

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Prioritization Approach

• Written Scoring
• Written Policy
• Engineering

Judgment / Committee Review

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Prioritization Methodology

• Prioritization Categories
• Structural Flooding
• Non‐Structural Flooding
• Existing Infrastructure Condition
• Miscellaneous Factors
• health and safety
• critical locations
• downstream impacts
• community development
• links to other utility projects

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Prioritization Methodology Example Prioritization Worksheet

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Previous Study Process

• Data Preparation / Data Collection
• Identify Deficiencies

– MicroStation GeoPak Drainage – 1‐D, Rational Method, steady flow

• Propose Drainage Improvements
• Prioritize Projects
• GIS Coverage and Database

– Imported from MicroStation

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Application

• Studied 10,000 acres of watershed
• 135 miles of pipe, 20,000 LF of open channel,

5,000 ancillary items

• Identified 150 CIP stormwater projects

– Dozens of projects proceeded to design/construction through funding from 2005‐2012 Stormwater bonds

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Current Urban Drainage Study

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Current Study Process

• Phase 1‐ Screening Level Analysis

– 1‐D, Rational Method, steady flow – Identify Storm System Deficiencies

• Pipe Capacity, Inlet Ponding Depths, Ponding Limits, Structural

Flooding

– Update GIS Database

• Phase 2‐ Detailed Analysis and CIP Development

– Optional 2‐D, unsteady flow – Develop CIP stormwater projects

• Evaluate conceptual alternatives

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Hydrology and Hydraulics

Screenshot of DGN map

ArcGIS XP SWMM

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Drainage system deficiencies based on design storm as defined in City design criteria manual. Pipes

(Discharge Relative to Capacity)

Inlets

(Ponded Depth at Inlet)

Ponding Areas

(Structural Flood Frequency)

Street Flooding

Stormwater System Deficiencies

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1-D/2-D Analysis

1-D Pipes/Open Channels 2-D Overland Flow/Flooding

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Flooding Animations

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CIP Project Development

• Structural Flooding
• Location
• City Design Standards
• Cost-Effectiveness

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CIP Project Development

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CIP Project Prioritization

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GIS Database Management

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GIS Database Management

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Model Validation

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Conclusion

• Cost‐effective approach to prepare a proactive

stormwater CIP

• Ensures taxpayers’ dollars spent on most

needed projects

• Helpful in justifying stormwater program

financing needs to elected officials and public

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Thank You! Questions?