THE Developing Stormwater GOLDILOCKS Master Plans that are Just - - PowerPoint PPT Presentation

Developing Stormwater Master Plans that are “Just Right” for your Community

THE “GOLDILOCKS” APPROACH

SEPTEMBER 11, 2014 KY ASSOCIATION OF MITIGATION MANAGERS LAKE BARKLEY, KY

GOLDILOCKS AND STORMWATER

 “The Story of the Three Bears”

• Wanders into the home of Papa Bear,

Mama Bear, and Baby Bear

• Tries their soup… one is too hot,

another too cold, one is just right

• Tries out a chair, and one is just right
• At some point, decides she needs

some rest, and finds a bed that is just right… only to be discovered, asleep when the bears come home

 So… how does this relate to stormwater master planning?

EVERY COMMUNITY IS DIFFERENT

Political Economic Physiographic

• Topography
• Stormwater System
• Severity of flooding

What does a stormwater plan look like that is “just right” for my community?

 Project Background

• Study Purpose
• Study Area

 Project Approach/Methods

• Scoping
• Data Collection
• Baseline Modeling
• Goals Assessment
• Alternatives Analysis

 Lessons Learned/Conclusions

OVERVIEW

Purpose and Study Area

PROJECT BACKGROUND

STUDY AREA

Owensboro

HISTORIC FLOODING

STUDY STREAMS

Our Study and the Methods We Used

PROJECT APPROACH

What question(s) do we want to answer? What is the appropriate level of detail? What methods will this require?

DEFINING THE SCOPE

Local officials: Manage your consultant!

• Express your concerns
• Be satisfied with the project goals – if not, let

it be known

Stakeholders

• Local Partner – Jim Riney, HRG PLLC
• County Officials
• Drainage Advisory Committee
• Public Meeting

THE LOCAL ADVANTAGE

Find the low- hanging fruit

• Studies done locally
• State GIS data
• LiDAR
• KYTC Record Drawings
• Data from Federal

Agencies

• FEMA studies
• USGS gages

DATA COLLECTION

Steady-State

• 9 of the 12 study

streams

Unsteady-State

• Panther Creek

system (Panther, NF, SF)

• Understand

combination of backwater and headwater effects

BASELINE STUDIES

Begin with the end in mind

• Models can be built upon if more detailed studies

are needed in the future

• Models can be leveraged in future FEMA

floodplain mapping efforts

Modeling of historic flood events

• Calibration/verification (NEXRAD, USGS, HWM)
• Communicates in terms of a flood locals know
• Can be used for “what if” scenarios

BASELINE STUDIES

STUDY AREA

Owensboro

ANIMATION

Pilot study to test initial project goals

• 2 streams
• 2 Events (2 yr, 100 yr)
• Roadway serviceability
• All roads?
• Or just major roads?
• Floodplain Reduction
• 0%
• 25%
• 50%

GOALS ASSESSMENT

Alternatives

• Roadway

serviceability

• Raising of roadway

profile

• Bridge replacement
• Floodplain

Reduction

• Detention
• Levees

Model & spreadsheet calculations to

• btain quantities
• Amount of detention
• Miles of roadway

raised, average height

• # of Bridge

Replacements

Performed cost estimates Selected final goals

GOALS ASSESSMENT

0% 10% 20% 30% 40% 50% 60% Cost Percent ntage age of Floodplain ain Reduc uction

• n

Coun unty ty-wide ide Cost st Estimat mate e using ing Det etentio ion

100-yr 2-yr

Roadway Modifications

• Modeled WSEL
• LiDAR bridge/roadway

elevations

• KYTC Bridge Plans
• KYTC Functional

Classification System

KYTC Functional Classes Description Functional Class Rural Interstate 1 Urban Interstate 1 Rural Principal Arterial 2 Urban Freeways & Expressways 2 Urban Principal Arterial 3 Rural Minor Arterial 4 Urban Minor Arterial Street 4 Rural Major Collector 5 Urban Collector Street 5 Rural Minor Collector 6 Rural Local Road 7 Urban Local Road 7

ROADWAY MODIFICATIONS

ROADWAY MODIFICATIONS

Apply goals to all study streams

• 12 streams
• 5 Events (2, 10, 25,

50, 100 yr)

• Roadway serviceability
• Major roads only (based
• n KYTC functional

classification)

• Floodplain Reduction
• 30% reduction goal

ALTERNATIVES ANALYSIS

Alternatives

• Roadway

serviceability

• Raising of roadway

profile

• Bridge replacement
• Floodplain

Reduction

• Detention
• Levees
• Channelization
• Straightening

ALTERNATIVES ANALYSIS

2 yr 10 yr 25 yr 50 yr 100 yr 20 40 60 80 100 120 Constructio truction n Cost, in in Doll llars Recurre urrence nce In Interval al of Flo lood d Eve vent nt, in in Year ars

Cost vs Flood d Event nt (All l St Streams) ams)

What are the key lessons?

CONCLUSIONS

• Overall
• Establish a level of detail that is appropriate to the question being

asked

• Manage the consultant – be happy with the result of the scoping process
• Find methods that are appropriate to the scale of the problem at hand
• Stakeholder involvement
• Technical
• Finding low hanging fruit: Leveraging existing data
• LiDAR, KYTC Bridge Plans, FEMA studies, Previous Studies
• Begin with the end in mind: Create models that can be used later
• Can be built upon if more detailed studies are needed
• Can be leveraged for more FEMA floodplain mapping
• Model historic events: A number of benefits
• Model calibration, public outreach, “what-if” scenarios

CONCLUSIONS

THANKS!

 Thanks to Mark Brasher, County Judge Executive Al Mattingly, Commissioners George Wathen, Charlie Castlen, and Jim Lambert, and the Daviess County Drainage Advisory Committee!  Thanks to Jim Riney, HRG