Transcript New Hampshire`s Public Water Systems Climate Change

New Hampshire’s Public
Water Systems
Climate Change Challenges
2014 Annual Meeting
Robert Scott, Commissioner, New Hampshire Public Utilities Commission
Indicators of Climate Change
in the Northeast
• More precipitation
• More frequent extreme
precipitation
• Winter warming
• Decreased snowfall
• Fewer days with snow on
ground
• Lake ice out dates earlier
• Earlier spring runoff
• Extended growing season
• Sea-level rise
Hodgkins et al., 2002; 2003; Wolfe et al., 2005;
Wake and Markham, 2005; Wake et al., 2006
Projections of Climate Change
in New Hampshire
• Increasing Temperatures
• By mid-century, 40 days over 90 degrees.
• By end of century, 65 days over 90
degrees.
• More water consumption
• Agriculture, lawn irrigation, cooling.
• Summer Precipitation
• Expected to stay the same or increase
slightly
This all adds up to water supply challenges
NH more susceptible to short and mediumterm drought than most are aware
• Only 14% of state covered
by stratified-drift deposits
• Most of NH has shallow
depth to bedrock
• Extreme rain events will
not recharge groundwater
at the same rate as our
historically more moderate
rainfalls
A Growing State
• We’ll likely have significant increases in demand
for drinking water as our economy and population
grows
• With growth there may be more competing
interests/users of our water resources
Storms/Flooding
While we will get more rain
on average, the storms will
be larger rather than more
frequent
We’ll see more runoff
rather than just more
infiltration and
groundwater recharge
Water Quality Concerns
Flooding
Risk of contaminants
entering wells
~bacteria, turbidity,
nitrates, and other
chemicals
An additional concern for
surface water sources is
increased turbidity (and
increased treatment cost)
City of Somersworth
Two events
•2006 – 100 Year Flood
•2007 – Flood approached
500-year event
• Fuel tank became buoyant
• Released 4000 gallons of
fuel oil
• Cost to clean up $170,000
Storms/Flooding
Infrastructure Impacts
• Power restoration – generators to meet power losses
• We are encouraging them to at least have transfer switches
installed so that they can readily accept a generator if they
need to bring on one in.
• Surface water impoundments in some smaller reservoirs
filling with silt and needing dredging
• Damage to facilities due to flooding and streambank erosion
Drought
Warmer summer temperatures - Likely lead to an increase in
drought (through increased evaporation, heat waves, and more
frequent and extreme convective precipitation events)
• Many systems developed to serve seasonal use, meaning
summer time peak usage
• Wells, surface water access and tank storage generally
designed and sized for historical conditions
• Systems with fire protection systems have additional burden
• Many older community water systems have leaky pipes
Water quality impacts - With surface waters, there would
be longer residence times for contaminants. And
contamination levels will likely be higher to begin with due
to higher temperatures
Drought
Adaptation Strategies
• Need for additional water storage
• Additional wells and capacity
• Availability of water to be trucked in
Drought
Water Conservation
• Water conservation needed so that wells are not drained
down before a drought sets in
• Water restrictions
• In 2010, 94 community water systems (CWS) had water
use restrictions
• In 2011, 45 CWS had water use restrictions.
• Although these weren’t technically drought periods,
there were low lake and groundwater levels affecting
water supplies. Usually the restrictions were in the form
of an outdoor water ban.
Water Quality Concerns
High Temperatures
Small Water Systems
• Majority of PWS in NH (655 out of 695) are small systems
serving 3,300 or less.
• Infrastructure enhancements that are rarely needed are a
costly burden for a small system
• Access to capital and/or disaster relief funds for small
investor owned utilities
• NH Public Works Mutual Aid program whereby private and
public water systems can pay a small annual fee and then
have access to equipment, supplies and other assistance,
from other PWS, during an emergency.