Climate Change Impacts in the Mountain West

Warmer and shorter winter seasons

• Increased glacial melting
• Decreased seasonal snowpacks
• More rain, more rain-on-snow, and earlier spring snowmelt

• Altered recharge of groundwater aquifers
• Earlier runoff into surface waters

• Lower summer and fall base flows in surface waters
• Lower summer and fall reservoir levels

Warmer and potentially drier summer seasons

• Changes in vegetation of watershed and aquifer recharge areas

• Altered recharge of groundwater aquifers
• Changes in quantity and quality (e.g. toxicity, alkalinity) of runoff into surface waters

• Increased water temperature

• Increased evaporation and eutrophication in surface sources
• Water treatment and distribution challenges (disinfection, byproducts, regrowth)

• Increased water demand

• Increased irrigation demand in longer growing seasons
• Increased urban demand with more heat waves and dry spells
• Increased drawdown of local groundwater resources to meet the above consumption

More frequent and intense rainfall events

• Increased turbidity and sedimentation

• Loss of reservoir storage

• Shallower, warmer water; increased evaporation and eutrophication
• Potential conflicts with flood control objectives

• Water filtration or filtration/avoidance treatment challenges

• Increased risk of direct flood damage to water utility facilities

From: Implications of Climate Change for Urban Water Utilities." Association of Metropolitan Water Agencies. Washington D.C: Stratus Consulting Inc., 2007.