New Hampshire Silver Jackets: Spring Report of State Hydrology and Watershed Conditions 2021
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New Hampshire Silver Jackets:
Spring Report of State Hydrology and Watershed Conditions
2021
NEW HAMPSHIRE SILVER JACKETS
A team of federal and state agencies
that focus on New Hampshire's flood
risk management priorities and
provide technical expertise and
resources in the development of
solutions and projects.
https://silverjackets.nfrmp.us/State-Teams/
New-Hampshire.cfm
From Bristol, NH Hazard Mitigation Plan
Current as of
February 26, 2021
Will be revised as conditions change
New Hampshire Silver Jackets:
Annual Spring Report of State Hydrology and Watershed Conditions
2021
Agenda
I. Welcome and Introductions
II. Current State of Watershed Conditions and Flood Potential
Streamflow
Groundwater
Snowpack
Weather Forecast Summary
Water Levels of Lakes
Ice Jams
Flood Potential and Conclusions for 2021
National Flood Insurance Program Update
Hazard Mitigation Program Update
III. Current State of Drought and Future Thoughts for 2021
IV. Discussion and Q & A on Sections II and III
V. Silver Jackets Information for Communities
New Hampshire Silver Jackets:
Annual Spring Report of State Hydrology and Watershed Conditions
2021
Logistics
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and then will open it up for attendees to raise their hands and ask a
question.
New Hampshire Silver Jackets:
Annual Spring Report of State Hydrology and Watershed Conditions
2021
• New Hampshire Silver Jackets has jointly compiled this information on status of
New Hampshire Hydrology, Watershed, Lake and River conditions in preparation
for spring snowmelt and runoff season of 2020.
• Individual agency team members have reviewed snowpack, existing river ice
conditions, streamflow, long-range weather and flood outlooks, and lake water
levels.
• Every spring, flood risks can be increased when rain is accompanied by
snowmelt. Such a situation can be made worse if rivers remain ice covered
when such events occur.
• It is important to note, however, that flooding does not always occur from
snowmelt alone, and are often driven by a precipitation event.
New Hampshire Silver Jackets:
Annual Spring Report of State Hydrology and Watershed Conditions
2021
Today’s Speakers
Streamflow Rick Kiah, USGS
Groundwater Shane Csiki, NHGS at NHDES
Snowpack Steve Doyon, NHDES Dam Bureau
Weather Forecast Summary Margaret Curtis, NWS – Gray
Water Levels of Lakes Steve Doyon, NHDES Dam Bureau
Ice Jams Steve Doyon, NHDES Dam Bureau
NFIP Update Samara Ebinger, NH OSI
Hazard Mitigation Update Meghan Wells, NH HSEM
Drought Thomas O’Donovan, Director,
NHDES Water Division
Spring 2021 Conditions and Flood Hazard Assessment
Streamflows
7-DAY AVERAGE RUNOFF FOR NEW HAMPSHIRE
• Record low 7-day
average runoff in
September 2020
• Minor flooding events in
December elevated
streamflow’s.
• Downward trend
through February is
lower than same period
last year.
More information: https://waterwatch.usgs.gov/index.php?id=ww
Spring 2021 Conditions and Flood Hazard Assessment
Streamflows
7-DAY AVERAGE CUMULATIVE RUNOFF BY WATER YEAR
• Evaluating by Water Year
(Oct to Sept) allows for
annual accounting of
precipitation and runoff.
• Record low cumulative
runoff in October 2020.
Observed cumulative runoff (2021)
• Water Year 2021 normal
but trending lower than
2020.
More information: https://waterwatch.usgs.gov/index.php?id=ww
Spring 2021 Conditions and Flood Hazard Assessment
Streamflows
CURRENT STREAMFLOW CONDITIONS FOR NEW HAMPSHIRE
13%
• Current (Feb 24) streamflow
39%
conditions are generally normal.
47% 9%
37%
• Connecticut River Basin is below
normal (regulated). Mainstem
Connecticut River is dominating
28% this classification.
29%
17% 23%
27%
24% 28% • Unregulated streams trending
27% 24% towards below normal conditions.
34%
16% 46% 30% https://waterdata.usgs.gov/nh/nwis/current/?type=flow
25% https://dashboard.waterdata.usgs.gov
35%
42%
47% 40%
42% 28%
Spring 2021 Conditions and Flood Hazard Assessment
Groundwater Levels
Summary
• NHGS monitors 31 groundwater wells
• January 2021: Many wells are near
normal levels for this time of year
• Majority of wells in southeast New
Hampshire and Merrimack Valley are
normal to above normal
• Connecticut River Valley is low
• Wells in Deerfield, Franklin,
Greenfield and Ossipee are below
normal
• The wells in Lancaster, Lisbon and
Newport remain low
• Precipitation and subsequent
snowmelt in December had raised
groundwater levels in much of the
state
Links to Groundwater Level reports on NHGS’ site:
https://www.des.nh.gov/sites/g/files/ehbemt341/files/doc
uments/nhgs-gwlevels-jan2021.pdf
Spring 2021 Conditions and Flood Hazard Assessment SOUTHEAST/
Groundwater Levels MERRIMACK
VALLEY
• Conditions have generally improved since
the summer drought.Spring 2021 Conditions and Flood Hazard Assessment SOUTHEAST/
Groundwater Levels MERRIMACK
VALLEY
• As the example from New London shows,
water levels were higher in wells in
December than in January, though many
remain at normal or above normal levels.Spring 2021 Conditions and Flood Hazard Assessment CONNECTICUT
Groundwater Levels RIVER VALLEY
• Levels in the Connecticut River Valley
remain low.Spring 2021 Conditions and Flood Hazard Assessment Snowpack Current Conditions - Depths
Spring 2021 Conditions and Flood Hazard Assessment Snowpack Current Conditions – Water Content
Spring 2021 Conditions and Flood Hazard Assessment Snowpack Current Conditions – Depth and Water Content – 2/17 NHDES Sample
Spring 2021 Conditions and Flood Hazard Assessment
Weather Forecast Summary
[Next week’s forecast.]
The next chance of precipitation is Saturday.
Additional precipitation possible next Thursday-Friday.
Expect mixed precipitation events with rain mixing south.
North will see additional snowpack.
Whitefield
ManchesterSpring 2021 Conditions and Flood Hazard Assessment Weather Forecast Summary [6-10 day outlook]
Spring 2021 Conditions and Flood Hazard Assessment
Weather Forecast Summary
[Temperature/precipitation forecast.]
The 6-10 day outlook is for ABOVE normal temperatures
and ABOVE normal precipitation.
Cold air remains in the west with an active storm track in
the east over the next few weeks.
Expect mixed precipitation events with rain mixing south.
North will see additional snowpack.Spring 2021 Conditions and Flood Hazard Assessment Weather Forecast Summary [8-14 day outlook]
Spring 2021 Conditions and Flood Hazard Assessment
Weather Forecast Summary
[Temperature/precipitation forecast.]
The 8-14 day outlook is for ABOVE normal temperatures
and Near NORMAL normal precipitation.
Normal temperatures rise above freezing across the south
with some snow melt expected.Spring 2021 Conditions and Flood Hazard Assessment Water Levels of Lakes Central NH
Spring 2021 Conditions and Flood Hazard Assessment Water Levels of Lakes Northern VT
Spring 2021 Conditions and Flood Hazard Assessment
Water Levels of Lakes
• “Big” lakes, which tend to be slower to respond to climactic
conditions, are near normal or within reasonable limits for this
time of year
• Recent snowfall across NH appears to be keeping the snowpack
near normal parameters
• NHDES water managers do not presently have concerns about a
higher risk of in-lake flooding, or of refilling lakes and ponds to
their summer levels
• Rainfall totals between March and May tend to set the tone for
sustaining normal levels throughout the summer
• River and Lake Levels:
https://www4.des.state.nh.us/Rti_home/ - NHDES
https://waterdata.usgs.gov/nh/nwis/current/?type=flow - USGSSpring 2021 Conditions and Flood Hazard Assessment
Ice Jams
Ice Jam Ingredients
• Potential exists for ice jams each
winter/spring
• What might cause a jam to form?
-extreme/prolonged cold
-low streamflows (increases
contact area between ice sheet
and streambed)
-obstructions and changes in
direction/slope
• What might fuel a jam?
-temperature (water and air)
-snowpack
-precipitation
-above-normal streamflowSpring 2021 Conditions and Flood Hazard Assessment
Ice Jams
Thermal Versus Mechanical Ice Out Scenarios
Thermal Melt Out Mechanical Breakup
• Ice melts in place • Rapid increase in streamflow from rapid
warmup and/or heavy rain; fractures
• Long, gradual warming period with no ice
significant rain
• Ice cover connection with streambanks
• Ice cover thins, weakens and melts in is fractured
place or is carried downstream in such
size and/or quantity as to present no • Stream channel ice begins to move and
dangers fracture into smaller and smaller pieces
• Can lead to breakup ice jams
- Changes in channel slope
- Sharp bends
These mechanical
- Constrictions
breakup scenarios are
- Obstructions (i.e., bridge piers)
what we have to
watch for and
continue to monitorSpring 2021 Conditions and Flood Hazard Assessment Ice Jams Managing and Addressing Ice Jams • Know where the ice jam potential is in your town/city • Have a system in place to monitor ice jams and track current and forecasted weather conditions • Conduct outreach to nearby residents as needed • Be prepared to close roads and bridges; and to evacuate potentially impacted structures • If ice jam removal is considered, reach out to ice jam experts for help with assessment/ideas - SAFETY FIRST
Spring 2021 Conditions and Flood Hazard Assessment
Flood Potential and Conclusions for 2021
• Normal flood potential exists for 2021 runoff season
• No indication of rapid warming with heavy rain during the next 2 weeks
• No known specific ice jams at this time, with no occurrences currently
reported. However, the usual locations known to experience jams should
be monitored. If you observe a jam, please contact your local NH HSEM
Field Representative.
• Most flooding is the result of heavy and persistent rain. Antecedent
conditions like soil saturation and snowpack may contribute to flooding.
• Groundwater levels are normal to above normal in south-
central/southeast New Hampshire, except for select wells under local
conditions; remain below normal in Connecticut River Valley
• Snow water equivalent is generally below normal except Upper Valley
and Coos County, which are near to above normalSpring 2021 Conditions and Flood Hazard Assessment
Flood Mapping - National Flood Insurance Program
(NFIP) Update
• Partnership between local communities and
the Federal government. 219 communities in
NH choose to participate in the program.
• NFIP communities adopt and enforce
floodplain management regulations to manage
development in Special Flood Hazard Areas on
FEMA flood maps.
• All residents and business owners in NFIP
communities can purchase NFIP flood
insurance regardless of whether or not they
are in a Special Flood Hazard Area.
• Visit www.nh.gov/osi/planning/programs/fmp
to learn more about the NFIP and floodplain
management in the state.Status of FEMA Flood Mapping Projects in NH Rockingham County Coastal Study – Updated flood maps for 15 communities became effective 1/29/2021. Merrimack/Nashua River Watersheds - Preliminary flood maps are expected to be issued in 2021. Contoocook/Pemigewasset River Watersheds – Development of new flood maps is in progress. Meetings with community officials to review draft work maps to be held in 2021. Middle Connecticut, Millers, and Winnipesaukee River Watersheds – Development of new flood maps is currently in progress. Waits River-Connecticut River, Ammonoosuc River-Connecticut River, Headwaters Connecticut River, and Upper Androscoggin River Watersheds– Discovery projects to determine scopes of work for new flood mapping projects are underway.
Hazard Mitigation Assistance (HMA) Programs
Hazard Mitigation grants are available to provide funding for eligible mitigation planning and
projects that reduces disaster losses and protect life and property from future disaster
damages.
Annually
*BRIC replaced FEMA’s
Pre-Disaster Mitigation (PDM)
Grant
Annually
Post Disaster
AnnuallyHazard Mitigation Assistance (HMA) Programs
BRIC
Eligible
ActivitiesHazard Mitigation Assistance (HMA) Programs
Rehabilitation
of High Hazard
Potential
Dams (HHPD)
Grant ProgramHazard Mitigation Assistance (HMA) Programs
Additional Questions?
Meghan Wells
NH State Hazard Mitigation Officer
Meghan.K.Wells@dos.nh.gov
Work: 603.223.4395 | Cell: 603.406.1292
Hazard Mitigation Planning
HazardMitigationPlanning@dos.nh.gov
HSEM Field Representative
603-223-3663Additional Presentations of Interest, Resources, Upcoming Trainings River Ice Webinar National Weather Service – Gray and Cold Regions Research and Engineering Laboratory Tuesday, March 9 – 3 to 4 PM https://attendee.gotowebinar.com/register/3272211888323974160 Ice Jam Observer Training Silver Jackets Projects (2017) https://www.des.nh.gov/sites/g/files/ehbemt341/files/documents/2020-01/ice-jam-presentation.pdf
Additional Presentations of Interest, Resources,
Upcoming Trainings
Floodplain Management Basics: Making Substantial
Improvement and Substantial Damage Determinations
March 31st and April 14th from 10am to 11:30am
A two-part webinar series for community officials about
making Substantial Improvement and Substantial Damage
determinations – a requirement for all NFIP communities.
For more information, including how to register, visit
www.nh.gov/osi/planning/programs/fmp
The NH Flood Hazards Handbook for Municipal Officials
• Developed by the NH Silver Jackets Team
• Includes guidance, best practices, and other information in situation-specific sections:
Before the Flood, During the Flood, and After the Flood (Short Term Recovery and Long
Term Recovery Considerations).
• Available for download at https://silverjackets.nfrmp.us/State-Teams/New-Hampshire.Speaker Contact Information Shane Csiki Shane.Csiki@des.nh.gov Margaret Curtis margaret.curtis@noaa.gov Steve Doyon Steve.N.Doyon@des.nh.gov Samara Ebinger Samara.M.Ebinger@osi.nh.gov Rick Kiah rkiah@usgs.gov Meghan Wells Meghan.K.Wells@dos.nh.gov Thomas O’Donovan Thomas.E.Odonovan@des.nh.gov
New Hampshire Silver Jackets Team
History of New Hampshire’s
Interagency Team
• 2011 – 2014
• Originally known as the
Post-Irene River Response
Team, which formed following
Tropical Storm Irene
• Federal and state agencies
responded to a multitude of
flood hazards & unprecedented
amount of post-storm recovery
& repair work
• Agencies involved agreed to
collaborate on administration of
post-Irene river related
activities
38National Silver Jackets Program
• State-led interagency teams
that bring together multiple
state and federal partners to
work collaboratively on flood
risk management issues.
• No single agency has all the
answers, but often multiple
programs can be leveraged to
provide a cohesive solution
• Federal participation includes
the U.S. Army Corps of
Engineers and FEMA.
• Technical assistance provided;
not a funding program.
39NH Silver Jackets Team
Overview
• 2015 – NH Silver Jackets Team
officially created with an
interagency agreement.
• Includes individuals from federal
and state agencies focused on
the state’s flood risk
management priorities.
• Provides technical expertise and
resources in the development of
solutions to manage flood risk in
the state.
• Serves as implementer of NH Silver Jackets team members assess the Gale
River at Route 3 for vulnerability to ice jams, 2017.
Recovery Support Function #6
(damage assessment) in the
State Disaster Recovery Plan.
40NH Silver Jackets Team
Agency Members
41NH Silver Jackets Team
Mission Statement
• Maintain and integrate comprehensive relationships with
federal, state and local agencies and programs to increase
awareness and reduce flood risk
• Facilitate partnerships related to mitigating and
recovering from flooding events in New Hampshire
• Establish an interagency approach to sharing and
combining resources, including funding, programs and
technical expertise as appropriate
• Recommend and facilitate the collaborative
implementation of strategic measures to proactively
reduce the risks of flooding in New Hampshire
• Provide coordinated assistance to communities and
individuals after a flooding event
42NH Silver Jackets Team
Goals
• Build a strong team of agencies with specific skills and
knowledge related to flood risk identification and
mitigation.
• Advise and assist NH communities in their efforts to
become more resilient and less vulnerable to flood
hazards.
• Increase public awareness and understanding of flood
risk and mitigation through the sharing and delivery of
resources to NH communities.
• Foster partnerships and facilitate cooperation in
achieving flood risk reduction.
• Assist with the prioritization of risk management tasks
during individual flood events.
43NH Silver Jackets Team
Projects
Year Project
2015 - 2016 Hinsdale Flood and River Vulnerability Assessment and Risk
Communication Project
• Provided town with necessary data and information to move
forward with addressing the identified flood risks
2016 - 2018 New Hampshire Ice Jam Assessment and Outreach Project
• Focused on Gale River at Franconia and Sugar Hill
• Developed ice observer training and ice jam outreach package
for all NH communities
2018 - 2019 New Hampshire Flood Hazards Handbook for Municipal Officials
• Resource guide to help communities prepare for, respond to,
recover from, and mitigate floods.
2019-2020 New Hampshire Flood Hazards Geodatabase
• Resource for communities to collect and document data, which
can be used for hazard mitigation planning and grants.NH Silver Jackets Team
Leadership
Chair:
Shane Csiki
State Flood Hazards Program Administrator
NH Geological Survey, Department of Environmental Services
Shane.J.Csiki@des.nh.gov
Co-Vice-Chairs:
Jennifer Gilbert
State National Flood Insurance Program Coordinator
NH Office of Strategic Initiatives
Jennifer.R.Gilbert@osi.nh.gov
Meghan Wells
State Hazard Mitigation Officer
NH Homeland Security & Emergency Management, Department of Safety
Meghan.K.Wells@dos.nh.gov
Team Website:
https://silverjackets.nfrmp.us/State-Teams/New-Hampshire
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