Flood Recovery: Lessons Learned Along the Way

Flood RecoveryFlood Recovery
Lessons Learned Along theLessons Learned Along the
WayWay
Prepared For:Prepared For:
The Cary InstituteThe Cary Institute
May 4, 2013May 4, 2013
By: Delaware County Department of Public WorksBy: Delaware County Department of Public Works

Requested topicsRequested topics
 How has Delaware County responded toHow has Delaware County responded to
floodsfloods
 Adaptations made to road infrastructureAdaptations made to road infrastructure
 Introduction to practices outside ofIntroduction to practices outside of
culvertsculverts
 Success stories and lessons learnedSuccess stories and lessons learned

OutlineOutline
 HistoryHistory
 EventsEvents
 Lessons LearnedLessons Learned
 Solutions that work for Delaware CountySolutions that work for Delaware County

Quick HistoryQuick History
 Open channel flowOpen channel flow

Trapezoidal channelsTrapezoidal channels

Uniform alignmentsUniform alignments

Lined for scour protectionLined for scour protection

Bermed for flood protectionBermed for flood protection
 January 19, 1996January 19, 1996

All new educationAll new education

FEMA Declared EventsFEMA Declared Events
 11 events in 15 years11 events in 15 years

January 19, 1996January 19, 1996

November 9, 1996November 9, 1996

May 13, 2004May 13, 2004

September 18, 2004September 18, 2004

April 5, 2005April 5, 2005

June 26, 2006June 26, 2006

November 16, 2006November 16, 2006

June 19, 2007June 19, 2007

April 26, 2011April 26, 2011

August 28, 2011August 28, 2011

September 8, 2011September 8, 2011

Numerous Undeclared EventsNumerous Undeclared Events
 June 1996June 1996
 July 1998July 1998
 July 2008 (FHWA Declared)July 2008 (FHWA Declared)
 October 2010 (FHWA Declared)October 2010 (FHWA Declared)

June 2006June 2006
 $14 million in damage$14 million in damage
 14 bridges closed14 bridges closed
 12 roads closed12 roads closed
 Wide spread damageWide spread damage
 Heavy damage on tributaries as opposedHeavy damage on tributaries as opposed
to 1996 which involved the main stems into 1996 which involved the main stems in
the headwatersthe headwaters

June 2007June 2007
 Localized eventLocalized event
 Watershed: 9.6 square milesWatershed: 9.6 square miles
 Extremely destructiveExtremely destructive
 4 lives lost4 lives lost
 1 never recovered1 never recovered
 Homes were lostHomes were lost
 6 to 8 inches of rain in 2 hour period6 to 8 inches of rain in 2 hour period

Some reports of up to 11” in 4 hoursSome reports of up to 11” in 4 hours
 In excess of $12 million in damageIn excess of $12 million in damage

2011 Event2011 Event
 5 Bridges lost5 Bridges lost
 20 damaged due to scour20 damaged due to scour
 Estimated $15 million in damageEstimated $15 million in damage
 Not as bad as Greene and Ulster CountiesNot as bad as Greene and Ulster Counties

Lessons LearnedLessons Learned
 We have to work with nature, we will notWe have to work with nature, we will not
win a battle with itwin a battle with it
 Keep big picture in mindKeep big picture in mind
 Monitor your workMonitor your work
 Flooding resilience is not cheapFlooding resilience is not cheap
 Important elementsImportant elements

AlignmentsAlignments

Hydraulic capacityHydraulic capacity

ScourScour

Structure typesStructure types

Town of HancockTown of Hancock
A Case StudyA Case Study
 Fish CreekFish Creek
 County Bridge on a Town RoadCounty Bridge on a Town Road
 Dead end roadDead end road
 Drainage Area: 11.29 square milesDrainage Area: 11.29 square miles

ColchesterColchester
 Horse BrookHorse Brook

Damaged in 1996Damaged in 1996

Cleaned outCleaned out

TU poster childTU poster child
• National recognitionNational recognition
• DEP sponsored Dave RosgenDEP sponsored Dave Rosgen

DPW/TU CooperativeDPW/TU Cooperative

County Bridge 17-21County Bridge 17-21
 Reconstructed in 1998Reconstructed in 1998
 Stream Design by TUStream Design by TU
 Incorporated floodplain drainageIncorporated floodplain drainage
 Step pool designsStep pool designs
 Special issues due to confluence withSpecial issues due to confluence with
BeaverkillBeaverkill
 Drainage area: 2.58 Square MilesDrainage area: 2.58 Square Miles
 Span: 17.3 feetSpan: 17.3 feet
 Opening: 121.1 square feetOpening: 121.1 square feet

Town of HancockTown of Hancock
Laing RoadLaing Road

Town of ColchesterTown of Colchester
 June, 2007June, 2007
 County Route 7County Route 7
 Watershed: 9.6 square milesWatershed: 9.6 square miles

Watershed AreaWatershed Area
 .44 Square miles.44 Square miles
 281 acres281 acres

Watershed AreaWatershed Area
 6.69 Square miles6.69 Square miles
 Span: 48 feetSpan: 48 feet

Solutions for Delaware CountySolutions for Delaware County
 Adopt hydraulic and hydrology standardsAdopt hydraulic and hydrology standards
 Three sided box culvertsThree sided box culverts
 Floodplain benchesFloodplain benches
 Floodplain drainageFloodplain drainage
 Geomorphology designsGeomorphology designs

Rock vanesRock vanes

Root wadsRoot wads

Natural vegetationNatural vegetation

Adopt StandardsAdopt Standards
 Standards adopted by the BOSStandards adopted by the BOS
 Our standards are sizing a replacementOur standards are sizing a replacement
structure to pass a Q 50 with 2 feet ofstructure to pass a Q 50 with 2 feet of
freeboard or pass Q 100 with gravity flowfreeboard or pass Q 100 with gravity flow
whichever is shorterwhichever is shorter
 Standards require scour protection for theStandards require scour protection for the
design stormdesign storm
 Standard is natural, living bottoms (threeStandard is natural, living bottoms (three
sided boxes or bridges as preferredsided boxes or bridges as preferred
 Strict bridge takeover policyStrict bridge takeover policy

Three Sided BoxesThree Sided Boxes
AdvantagesAdvantages
 More capacityMore capacity
 Square more efficient than roundSquare more efficient than round
 More scour protectionMore scour protection
 Better fish passageBetter fish passage
 Can precast in winterCan precast in winter

Floodplain DrainageFloodplain Drainage

Town of HamdenTown of Hamden
 20112011
 Existing Pipe: 9’ X 5’ elliptical CMPExisting Pipe: 9’ X 5’ elliptical CMP
 Watershed Area: 3.06 square milesWatershed Area: 3.06 square miles
 Q50: 586 cfsQ50: 586 cfs
 Q100: 681 cfsQ100: 681 cfs
 Design bankfull width: 16.7 feetDesign bankfull width: 16.7 feet

Town of StamfordTown of Stamford
 20122012
 Watershed Area: 4.69 square milesWatershed Area: 4.69 square miles
 Original crossing: 6’ diameter pipeOriginal crossing: 6’ diameter pipe
 Existing Capacity: less than Q 1.25Existing Capacity: less than Q 1.25
 Q 50: 1195 cfsQ 50: 1195 cfs
 Q100: 1374 cfsQ100: 1374 cfs
 Construction Cost: $247,000Construction Cost: $247,000

Great PartnersGreat Partners
 Delaware County Soil and WaterDelaware County Soil and Water
Conservation DistrictConservation District
 Delaware County Planning DepartmentDelaware County Planning Department
 Delaware County Watershed AffairsDelaware County Watershed Affairs
 New York City Department ofNew York City Department of
Environmental ProtectionEnvironmental Protection

 Design for good wildlife habitat and thereDesign for good wildlife habitat and there
is a very good chance that you will get ais a very good chance that you will get a
durable infrastructure.durable infrastructure.
 Design for durable infrastructure and thereDesign for durable infrastructure and there
is a very good chance that you will get ais a very good chance that you will get a
durable infrastructure.durable infrastructure.

 Life as we knew it seems to have passedLife as we knew it seems to have passed
 For whatever reason, the climate hasFor whatever reason, the climate has
changedchanged
 We need to really think about the futureWe need to really think about the future
 As an engineer, I am convinced that weAs an engineer, I am convinced that we
need to get homes and businesses out ofneed to get homes and businesses out of
the floodplainsthe floodplains
 We really need to plan for future safetyWe really need to plan for future safety

Flood Recovery: Lessons Learned Along the Way

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