Drinking Water and the Lake There are 40+ plants utilizing Lake Michigan Water Illinois, Wisconsin, Michigan, Indiana Sizes of 1 MGD to 1 BGD Designed for 100 year Lake lows and highs

Numerous Treatment Processes Filtration –Sand, anthracite, granular activated carbon, membranes Disinfectantion –Chlorine gas, bleach, chloramines, ozone, investigating ultra-violet disinfection

Excellent Water Source Regulated substances include: –Arsenic is 50 times lower than standard –Barium is 10 times lower than standard –Nitrate is 20 times lower than standard –Bacteria routinely exceed standards Over 360 other compounds are monitored and not detected.

Climatic Change Factors Source water –Water level –Water quality –Water temperature Water demand –Precipitation –Temperature

Lake Level Impacts High Water Levels –Some shore facilities may require flood protection –Ability to supply water to plant may improve Low Water Levels –Improved protection of shore facilities –Some intake may require extension

Typically 1000 – 5000’ out into the Lake Typically 25 – 40’

Primary Water Quality Impacts Algal mass –Impacts how often filters require cleaning –Taste and odors in the Lake Turbidity –Impacts treatment chemical usage –Sludge removal operations –Filter runs

Water Temperature Water Production –Ice formation on intakes slows flow Water Treatment –Coagulation and flocculation –Disinfection

Water Demand Water production can double in the Summer Sustained hot dry weather increases demand Water plants sized and expanded to meet maximum flow day

Global Warming Impacts Water Treatment –Providers are confident that potential challenges are surmountable Water Production –Some intakes may require extension to deeper water –Most providers cautiously optimistic about impact of a one meter drop in Lake level

West Shore Water Producers Association