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.