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Windsor Woods Tide Gate
Stop the Tide, Save the Storage
July 31, 2020
Hampton Roads Adaptation Forum
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Presenters
Michael Bumbaco III, PE City of Virginia Beach Stormwater
Nicole Dane, PE Michael Baker International
Curtis HickmanWetland Studies and Solutions Inc.
PROJECT AREA
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AtlanticOcean
Chesapeake Bay
Oceana Naval Base
City ofVirginia
Beach Limits
Lynnhaven River
MountTrashmore
Park
PROJECTAREA
N
TownCenter
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Total Project Area – 2,600 Acres (8,500 Parcels)Windsor Woods – 1,300 Acres (3,700 Parcels)
Princess Anne Plaza – 1,100 Acres (3,800 Parcels)The Lakes – 185 Acres (1,000 Parcels)
Total Assessed Value – $2B
Windsor WoodsPrincess Anne
Plaza
TheLakes
▪ Flooded Homes and Property Damage
▪ Flooded Roads
▪Access Limited for:
o Emergency First Responders
oCity Maintenance Crews
oResidents
▪Areas Isolated until Flooding recedes
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The Problem = Flooding
▪ Infrastructure is ± 50 years old (Built in 1960’s)
▪Area is Fully-Developed
▪ Existing storm drains are inadequate or non-existent
▪ Lack of storage
▪ Elevations in the area are low and flat
▪ Frequency & severity of storms is increasing
▪Area is tidally influenced
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Why the Problem?
PROJECT AREA
Tidal Influence & Natural Drainage
Patterns7
PROJECTAREA
AtlanticOcean
Chesapeake Bay
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City ofVirginia Beach
Limits
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Risk Assessment Map
Sewells Point Tide Gauge Data
24-Hour Precipitation Return PeriodNorfolk Airport Rain Gauge (NOAA/NWS)
Hurricane Matthew
▪ Rainfall from Hurricane Matthew (Oct 2016) resulted in extreme flooding
▪ 800 Residences Reported Damage (Modeling approximates over 1,400)
▪ Many streets were impassable
▪ Flood Insurance Rates have significantly increased
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Flooding from Hurricane Matthew (2016)
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Work Leading to the Tide Gate?
▪ Public Outreach and Involvement
▪ Windsor Woods Stormwater Management System Flood Mitigation Plan -CDM Smith - April 2018
▪ Final Windsor Woods Drainage Improvements PER –Michael Baker – September 2019
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Overall Solutions
▪Gates to Block Incoming Tide
▪ Stormwater Pump Stations
▪Additional Storage
▪ Flood Barriers
▪ Storm Drains
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Overall Preliminary Concept Plan(Recommended Infrastructure)
Lynnhaven P
kw
y
Lake
Windsor
Lake
Trashmore
Northgate Plaza
Ball Fields
POTENTIAL STORMWATER
STORAGE
NEW STORM DRAINS WILL BE
INSTALLED THROUGHOUTTHE PROJECT
AREA
POTENTIAL NORTH PUMP STATION,
TIDE GATE & BARRIER
LOCATION
WINDSOR WOODS PUMP STATION, TIDE GATE &
BARRIER LOCATION
POTENTIAL SOUTH TIDE GATE,
CHANNELS & BARRIER
LOCATION
Windsor Woods Tide Gate Project
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▪ Windsor Woods Tide Gate Selected by City to Move Forward
o Tide Gate (60 feet wide; 4 bays)o Pump Station (750 cfs)o Barriers (100-year)
Gate Blocks Incoming Tide Stormwater Storage
Windsor Woods
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Lake Trashmore
Natural Drainage Patterns
Windsor Woods
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Tidal Impacts
Lake Trashmore
Windsor Woods19
Proposed Pump
Station
Proposed Tide Gate
Lake Trashmore
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Proposed Barrier
Windsor Woods
Lake Trashmore
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Windsor Woods Tide Gate & Pump Station Site
Lake Windsor
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Windsor Woods Tide Gate & Pump Station Rendering
Lake Windsor
Windsor Woods Tide Gate Rendering
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Windsor Woods Tide Gate & Pump Station Rendering
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Windsor Woods Tide Gate & Pump Station Site
Lake Windsor
Lake Windsor
Lake Windsor
Mount TrashmoreSkatepark
Mount TrashmoreSkatepark
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Lake Windsor – Ex. Conditions (Low Tide)
Water Level at Low Tide
Thalia Creek
Lake Windsor
High Tide –
Low Tide –
UPSTREAMDOWNSTREAM
Available Storage Capacity at Low Tide
Natural Flow of Drainage
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Lake Windsor – Ex. Conditions (High Tide)
Water Level at Low Tide
Thalia Creek
Lake Windsor
Water Level at High TideHigh Tide –
Low Tide –
Tide Fills Available Storage
Incoming Tide
UPSTREAMDOWNSTREAM
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Lake Windsor – Ex. Conditions During Storm
Lake WindsorThalia
Creek
UPSTREAMDOWNSTREAM
Storage Capacity Exceeded Quickly and Flooding Occurs
Low Tide –
High Tide –
Water Level at Low Tide
Water Level at High Tide
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Lake Windsor – After Tide Gate Installation(Post-Improvements)
Water Level at Low Tide Lake
Windsor
Water Level at High Tide
Tide Gate in the Open Position
Normal Water LevelHigh Tide –
Low Tide –
UPSTREAMDOWNSTREAM
Thalia Creek
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Lake Windsor – After Tide Gate Installation(Post-Improvements)
Water Level at Low Tide
Lake Windsor
Tide Gate in the Closed Position
High Tide –
Thalia Creek
UPSTREAMDOWNSTREAM
Low Tide –
Storage Now Available Since Tidal Influence Eliminated
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Lake Windsor – After Gate & Pump Installed
Lake Windsor
Tide Gate and Pump Station In
Operation
High Tide –
UPSTREAMDOWNSTREAM
Pumps Used to Maintain Water
Levels Behind Gate
Additional Storage Created
by Pump Drawdown
Low Tide –
Thalia Creek
Regulatory
Pump Station
Storage(Water Quality)
Gates & Barriers
Storm Drain Network
Key Program Components
Regulatory Permitting
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▪ Permitting o Corps and DEQ Individual Permits
o Early Regulatory Coordination and Agency Involvemento Public Outreach and Buy Ino Alternatives Evaluation – Couldn’t Have Found a Better Site
▪ Aquatic Life o Frequency and Duration of Closureo Maintenance of Low Flow o Intake Structures – Entrainment
This is a Great Site for LEDPA!!!
34LEDPA – Least Environmentally Damaging Practicable Alternative
Fish Passage - Frequency and Duration of Closure
▪ Typically open during “Sunny Day” conditions
▪ Closed ~5-8 times a year
▪ ~24 to 48-hour pre-storm pump down
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Maintenance of Low Flow - Aquatic Life
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Intake Structures - Entrainment
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Intake Structures
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All Permits Received
▪ USACE and DEQ Individual Permits Issued
▪ No VMRC Permit Required
▪ A separate permit will be necessary for the larger pump.
▪ And the process starts again!
Future Permits
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Summary/Take-Aways
▪ Tide gate is the first project in this multi-faceted Long-term Program
▪ Permitting is Critical for Large Water Dependent Projects
▪ Regulatory Coordination needs to be Integral in Planning Process
▪ Public Involvement/Buy-In Important
▪ Pre-Storm Planning & Preparation is Critical
▪ Long-Term Operation & Maintenance Required
▪ Construction Anticipated Spring 2021
Thank You!
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