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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
Hodgkins et al., 2002; 2003; Wolfe et al., 2005; Wake and Markham, 2005; Wake et al., 2006
• 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
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
• 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
NH more susceptible to short and medium-term drought than most are aware
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/FloodingWhile 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 ConcernsFlooding
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 SomersworthTwo 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
• 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
Infrastructure Impacts
DroughtWarmer 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
DroughtAdaptation 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 ConcernsHigh 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.