Hudson Estuary WatershedHudson Estuary Watershed Resiliency Project -Resiliency Project
Dams
Alon Dominitz P EAlon Dominitz, P.E.Chief
Dam Safety SectionDam Safety Section518-402-8185
http://www.dec.ny.gov/lands/4991.html
NYS Department of Environmental Conservation1
What is a dam?
• An artificial barrier that impounds or may impound waters (Part p y p (673)
• “An Owner must at all times operate and maintain said structure and all appurtenant structures in a safe condition” (ECL 15-0507)
NYS Department of Environmental Conservation2
pp ( )• Does not include wastewater (ex: CAFO lagoons)
Types of damsEarth dam
Gravity dam
Buttress Dam
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Arch dam
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Dams Sometimes FailSouth Fork 1889 2,209Teton 1976 11Ka Loko 2006 7Hadlock 2005 0D lhi 2010 0Delhi 2010 0
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Internal Erosion
NYS Department of Environmental Conservation6 3-6Fowler Finch Pond Dam, Delaware County March 2011
Inadequate Spillway Capacity/ Surface Erosion
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Concrete Dam stability
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Undermining of SpillwayUndermining of Spillway Toe
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Dam Hazard ClassificationDam Hazard Classification
Class BIntermediate
Hazard
Cl C
Hazard Potential
Class A Class CHigh
Hazard
Class ALow Hazard Hazard
PotentialPotential
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Hazard Class Can Change
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With Increasing Hazard gClassification A→C
• Dam Owner responsibilities increase• Design standards increase• Regulatory requirements increaseg y q• Time, money and effort increase
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Spillway Capacity RequirementsSpillway Capacity Requirements(DEC Guidelines for Design of Dams)
Hazard Class Spillway Capacity*
A – Low 100-yearB I t di t 150% f 100B – Intermediate 150% of 100-yearC – High ½ Probable Maximum Flood
* Existing dams
Spillway capacity is the ability of the dam’s spillway system to pass inflow after routing through the reservoir. It is therefore affected the watershed, spillway hydraulics, and available storage in the reservoir.
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NYS Dam Safety ProgramR l i i b DEC• Regulatory inspection by DEC engineers
• Technical review• Monitoring of Owner Dam
Safety Programs• Repair or removal of dams by p y
owners• Enforcement • Emergency planning assistanceg y p g• Repair or removal of dams
when the owner fails to follow an Order
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NYS Dam Safety Framework• Owner Responsibility & Safety
ECL 15-0507Part 673
• Construction PermitsConstruction PermitsECL 15-0503/ 15-0511Parts 608/ 621
• Technical Standards/ Guidance“Guidelines for Design of Dams”Guidelines for Design of DamsTOGSOther industry guidelines,
research, etc.Engineering judgmentg ee g judg e
• Report of Safety InspectionsECL 15-0516
Dam Inventory - No “registry”
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Dam Inventory - No registry
Dam Safety Permit Thresholds
HT ‐Feet
15’
PERMIT
REQUIRED
NO
M H HEIGH
6’
REQUIRED
PERMIT
DA
6
REQUIRED
IMPOUNDMENT STORAGE – Million Gallons
1 3
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Code of Hammurabi - Section 53circa 1800 B.C.
If anyone be too lazy to keep his dam in proper condition, and does not so keep it;
if then the dam breaks and allif then the dam breaks and all the fields be flooded,
then shall he in whose dam the break occurred be sold for moneymoney,
and the money shall replace the h h d t b
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corn he has caused to be ruined.
ALL DAMS BY OWNER TYPE(State Dam Inventory)
4178PRIVATE
822
454
LOCALGOVERNMENT
STATE 454
102
STATE
PUBLICUTILITY
44
UTILITY
FEDERAL
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HIGH HAZARD DAMS BY OWNER TYPETYPE
(State Dam Inventory)
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Owner Responsibilities
• Inspection• Maintenance• Repair• Operation• Monitoring• Emergency Action• Regulatory complianceg y p
ECL 15-0507 “An Owner of a dam … shall at all times operate and maintain said structure … in a safe condition … ‘Owner’ means any
l l bli ti h t t t i
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person or local public corporation who owns, erects, reconstructs, repairs, maintains or uses a dam or other structure which impounds waters.”
NYSDEC Regulations:Part 673 “Dam Safety”Part 673 Dam Safety
What do the owners have to do?• Recordkeeping• Property Transfer
• Inspection and Maintenance Plan
Notification• Safety Inspection
• Emergency Action Plan• Annual Certification
• Engineering Assessment
• Report Flow in Auxiliary Spillway
• Financial Securityp y
• Enhanced Safety Program
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Typical Dept.Inspection Reportp p
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Dam Emergency Responsibilities
DAM OWNER GOVERNMENTDAM OWNER GOVERNMENT
• Warning• Detection
Warning
• Evacuation• Notification
• Evacuation
• Recovery• Prevent sudden release of water
• Recovery (impacted area)
NYS Department of Environmental Conservation23Dam Safety program oversees owner, advises governments
Emergency Action PlansEmergency Action Plans• Uniform Planning Process• Decades-old industry standard• Decades-old industry standard
for High Hazard dams• Required for Federal Energy
Regulatory CommissionRegulatory Commission (FERC) dams
• Part of FEMA’s “Model State Dam Safety Program”Dam Safety Program
• Over 60% of High Hazard dams in NY had EAP’s before the new regulations but many werenew regulations, but many were over 10 years old
• Currently over 95% of High Hazard dams have EAP’s but
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Hazard dams have EAP s, but some don’t meet requirements
Emergency Action Plans - Part 673.7
– Class B – Within 24 months - August 19, 2011 (Passed!)Cl C Withi 12 th A t 19 2010 (P d!)– Class C – Within 12 months – August 19, 2010 (Passed!)
– Newly classified dams – Within 12 months of being reclassified
• Class C – full EAP• Engineer inundation map• 1 or more notification flowcharts1 or more notification flowcharts• Other provisions: preparedness, exercising, etc.
• Class B – “EAP lite”• Typically Rougher inundation map• Typically Rougher inundation map• Typically Simple notification flowchart/ list
• Both require coordination with local Emergency Mgrs!
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Dams Provide Important Public Functions and Services
• Scenic and recreation• Water supply• Flood attenuation• Hydroelectric• Some natural resource
fbenefit depending on your perspective (different habitat)habitat)
• But, we must remember - they aren’t “natural” or permanent
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“natural” or permanent
Dams Affect Streams in Many waysFundamental change from natural
waterbody to an artificial pond or lake y p
The presence of a dam can significantly alter both
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upstream and downstream of the dam
Impacts Beyond the ImpoundmentImpacts Beyond the ImpoundmentDisrupts river continuum
– Barrier to upstream (and downstream) movement-not just fishnot just fish
– Alters sediment, nutrient and debris transportp
– Flow (sometimes)– Water quality can be
d d ddegraded• Temp• DO
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Impacts can reach miles downstream
Other “People” Impacts• Danger to
canoeists and k kkayakers
• Upstream and downstream flooding riskflooding risk
Greenhouse gas?NYS Department of Environmental Conservation29
• Greenhouse gas?
How much do dams affect the Hudson River watershed?
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You Be The JudgeOnly DEC inventory shownOnly DEC inventory shown
1900 2000
• “Golden Age of Dam Building” 1950 1970Building” 1950-1970
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Current and Past Efforts: Inventory and remove barriers
•180 sq. miles•651 Culverts•651 Culverts•184 dams(64 DEC inventory)
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Flood Reduction with non-FloodFlood Reduction with non-Flood Control Dams
The development of a coordinated flood control system will likely take years of y y ystudy, analysis, negotiations, funding, design and construction. It will require g qstrong and consistent local leadership. Technical and funding assistance may be g yavailable from NRCS or the USACE.
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Dam Removal / BreachBenefits and Challenges
• Removal/ reduction of flood hazard from dam failure• Removal/ reduction of flood hazard from dam failure• Relief from regulatory and civil liability of dam ownership• Possible reduction of upstream flood hazard• Restoration of natural stream conditions/ fish passage• Beauty/ recreational opportunities/ habitat in stream and on formerly
flooded land
• Construction project – stream disturbance, sediment management, p j , g ,construction stormwater, flood plain development, dam safety, etc.
• Possible increase of downstream flood hazard from loss of flood attenuation
• Loss/ reduction of lake – recreation, water supply, habitat, hydrooss/ educt o o a e ec eat o , ate supp y, ab tat, yd o
Every project has a unique history, setting, concerns, and challenges. Generally, the size and complexity of the breach/ removal project is similar in magnitude to the size of the original dam construction project.
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similar in magnitude to the size of the original dam construction project.
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New Waterville Dam
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CLOMR/ LOMRFl d M R i iFlood Map Revisions
• Physical Change to Floodplain such as Fill or Stream Changes; or
• Changes to Map and/or Study due to Updated Technical DataData
• CLOMR: Conditional Letter of Map Revision for a Proposed Project – need FEMA review of proposed revised map
• LOMR: Letter of Map Revision.• Official Revision of FIRM (and FIS) to show changes in
fl d l i fl d fl d l tifloodplains, floodways, or flood elevations• Up to 12 forms – MT-2• Community Acknowledgment Always Required
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• Community Acknowledgment Always Required
Community ResponsibilityCommunity Responsibility• Must Require LOMR for Physical Changes
Causing an Increase OR Decrease in Base FloodCausing an Increase OR Decrease in Base Flood Elevation.
44 CFR 65 3– 44 CFR 65.3– Six Month Deadline
• May Not Permit Floodway Encroachment unless• May Not Permit Floodway Encroachment unless – No Increase in BFE, Engineering Analysis
Required; orRequired; or– Conditional LOMR Received
• 44 CFR 60 3(d)
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• 44 CFR 60.3(d)
Information and Publications• Fact Sheets for Dam
Owners• Guidelines for Design of Dams
(1989) Owners– Dam Inspections by Owners– Burrowing Animals
(1989)• Owners Guidance Manual for
the Inspection and Maintenance of Dams in New York (1987)
– Trees and Brush Near Dams– Etc.
• Dams Inventory on Google
of Dams in New York (1987)
• Emergency Action Plans –DOW TOGS 3 1 3 Dams Inventory on Google
Earth• DRAFT Guidance for Dam
Ha ard Classification
DOW TOGS 3.1.3• Guidance for Dam Engineering
Assessments –DOW TOGS 3 1 4 Hazard Classification -
DOW TOGS 3.1.5DOW TOGS 3.1.4
http://www.dec.ny.gov/lands/4991.html
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p y g
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