Climate Change Threat Reduced Snowpack 1

Potential Impacts Related to Reduced Snowpack How might our community be impacted by reduced snowpack? 2

Reduced Snowpack Impacts: Changes in Seasonal Runoff 3

Extreme Event Example: Sierra Nevada Mountain Snowpack, California Climate projections suggest that there will be significant changes in rainfall and runoff patterns as average temperatures increase Projections indicate that the Sierra Nevada snowpack, the major storage reservoir of CA’s water, could diminish by 80% by the end of this century 4

Extreme Event Example: Continuous Drought Conditions, Washington Multiple droughts since 1971 caused dry stream beds, withered and abandoned crops, dead fish, record low river levels and declining aquifer storage Between 2000 and 2005, Washington State experienced two drought emergencies Washington has experienced exceptionally dry periods almost every year since

Adaptation Options for Changes in Seasonal Runoff Monitor precipitation, snowmelt and river discharges Develop water quality models and incorporate predictions of snowpack and runoff changes Update drought contingency plans to identify triggers that would result in demand management activities Diversify water supplies through use of recycled water, desalination, stormwater capture and conjunctive use (use of both surface water and groundwater) Increase storage capacity in reservoirs 6

Adapting to Changes in Seasonal Runoff Example: Portland, OR Portland Water Bureau relies on precipitation during the winter months to supply increasing demand in the summer months The utility analyzed four different climate model projections and regional population growth projections Models consistently project increased winter precipitation, earlier snowmelt (spring runoff could increase by 15%; late spring runoff decrease by 30%) and drier summers 7

Adapting to Changes in Seasonal Runoff (cont‘d) Example: Portland, OR Reduced summer precipitation combined with increased seasonal demand may lead to decreased reliability of the supply Portland Water Bureau is considering the following: Expanding groundwater supply Surface water storage Conjunctive use strategies to coordinate optimal use of surface/groundwater supplies Aquifer storage and recovery 8

Reduced Snowpack Impacts: Volume Changes and Lower Lake and Reservoir Levels 9

Adaptation Options for Volume Changes and Lower Lake and Reservoir Levels Develop alternative water supplies or increase storage Build systems to recycle water for energy, industrial, agricultural or household use Retrofit intakes Establish regional interconnections Update your drought contingency plan to include triggers for when the utility will implement water demand management strategies Work with the agricultural industry to reduce water demand Increase monitoring activities 10

Adapting to Volume Changes Example: Metropolitan Water District of Southern California (Metro) Metro is a wholesale water supplier for southern California. Over the past decade, water supplies have been supplemented and storage capacity has increased tenfold through: Aggressive conservation programs Local water recycling Groundwater supplies Enhanced water storage Water transfers Metro developed more than 75 water recycling and groundwater recovery programs with local agencies Metro increased storage capacity tenfold (Diamond Valley Lake; new groundwater storage and acquiring storage in state reservoirs) Leader in voluntary water transfers with agricultural districts 11

Adapting to Lower Lake and Reservoir Levels Example: Las Vegas, Nevada Southern Nevada Water Authority (SNWA) receives 90% of its water from one reservoir Lake Mead elevations have declined more than 100 ft. in the last decade (4 trillion gallon loss) Concerns include further reductions resulting from climate change Demand management practices implemented to reduce consumption (down 32% since 2000) Instituted new management actions: Infrastructure enhancements (including completion of second intake, ongoing construction of third deeper intake and additional water treatment capacity using ozone) 12

Reduced Snowpack Impacts: Altered Water Quality 13

Adaptation Options for Altered Water Quality Monitor water quality in receiving waters Finance and facilitate systems to recycle water to decrease pollutant discharge to receiving waters Work with regulatory agencies to discuss options for compliance Increase treatment capabilities 14

Adapting to Altered Water Quality Example: Spartanburg Water, South Carolina The utility is comprised of the Spartanburg Water System (SWS) and Spartanburg Sanitary Sewer District (SSSD) Wastewater discharges constitute up to 80% of streamflow Future droughts of increased frequency and severity may affect wastewater system operations 15

Adapting to Altered Water Quality (cont’d) Example: Spartanburg Water, South Carolina Spartanburg Water is taking a holistic, integrated approach and is considering water supply in conjunction with wastewater treatment SSSD’s largest wastewater treatment plant is located just downstream from their second largest water supply source Coordination of reservoir releases with the wastewater system can help to lessen water quality issues associated with wastewater discharges 16

Community and Economic Impacts Service disruptions can cause customers to lose confidence in their utility’s ability to provide clean and safe water to customers Local businesses suffer and may lose revenue if they lack reliable access to water or sewer services What can be done? Collaborate with other community partners to develop more sustainable community and regional plans Discuss adaptation options with local businesses Work with local governments to communicate adaptation activities and plans to customers 17