Bloomingtons Water Supply:System Overview and Planning by: Rick Twait, Superintendent of Water PurificationCity of BloomingtonMahomet Aquifer ConsortiumMeeting No. 56 October 22, 2007

Source: Illinois State Water SurveyIllinois Water Budget (Billion Gallons/ Day)

Bloomington, Illinois Water Utility77,000+ Customers75,000 City Residents2,200+ Customers from Villages and Public Water Districts11,400,000 Gallons Average Daily PumpageApproximately 80% Residential ConsumptionBNWRD Discharges ~20 mgd

Bloomingtons Two Water Supply Reservoirs

Lake BloomingtonEvergreen Lake

Constructed in 1929Constructed in 1971Raised 5 feet in 1954Raised 5 feet in 1995635 surface acres900 surface acres8,760 acre-ft storage15,480 acre-ft storage69.5 sq.mi. drainage area41.1 sq.mi. drainage area70:1 drainage to surface area ratio 29:1 drainage to surface area ratio

Dry Spells to DroughtsIn Detecting Drought Conditions in Illinois Changnon (1987): Described Meterological, Agricultural, Hydrological, and Economic Drought ConditionsUS Drought Monitor (website): Describes conditions in terms from abnormally dry to exceptional drought, agricultural and/or hydrologic

Dry Spells to DroughtsIn Drought Response Plan, City of Bloomington, Illinois Water Department, Wittman (2006) proposed a practical definition of drought for municipal water systems as:A reduction in precipitation or aquifer recharge that affects the ability of the public water system to meet the demands of the customers or causes regulatory or aesthetic reductions in water quality.

Types of Municipal Water ShortagesSupply Shortages Can be Caused by:DroughtDemandQuality:Health (Regulatory)Aesthetic

Types of Municipal Water Shortages (contd)Treatment Shortages Can be Caused by Inadequate:

Treatment CapacityTransmission CapacityStorage Capacity

To Meet Demands

400xHeterocystBluegreen Algal Filament

400x

1988-89 DroughtWater ProblemsExtremely Low Reservoir LevelsConcerns about Getting Water to Pump Intakes Extremely High Demands:Decreased Treatment EfficiencyPlant Operated at Peak CapacityLow Water QualityTaste and Odor Episodes Frequent and Severe

1988-89 DroughtOperational ResponsesWater RestrictionsLawn WateringWater Served in Restaurants by RequestTaste and Odor KMnO4CuSO4PACPurchase Floating Pumps

1988-89 DroughtPlanning/Supply ResponsesF&W Long Term Water StudyInitiate Watershed Protection ProgramRaise Evergreen Lake Spillway by 5 FeetBuild and Obtain Permit for Mackinaw River Pumping PoolRaised Water RatesInstalled GAC Caps on FiltersBegin Planning and Investigation of Groundwater Source

1988-89 DroughtPlanning/Supply Responses (continued)Expand Treatment Plant Capacity at Lake BloomingtonConstruction of 2 MG Elevated TankConstruction of Additional Transmission Main from Lake Bloomington to Town

Bloomington, Illinois Finished Water Nitrate Levels

Raising Spillway Elevation of Evergreen Lake Increased Capacity by 36%

Additional Watershed Area Due to Mackinaw River Pumping Pool

Drought of 2005Demand Hit Plant CapacityCool Period Limited Duration of Extreme DemandExtra Capacity of Evergreen Lake Extended Days of Available SupplyHigher Reservoir Levels, GAC Caps, and Destratifiers Resulted in Fewer T&O Issues (initially)

Drought of 2005Pumping Pool: From late December 2005 through April 2006: 364 million gallons pumped (over a months supply at average usage) despite no/minimal runoff to lakes from tributariesExtra capacity of Evergreen Lake Reservoir resulted in more reserve capacity at start of drought

Responses to the Drought of 2005Contracted with Wittman Hydro Planning Associates for Drought Response Plan and Draft Drought OrdinancePerformed Intensive In-House and Contracted Studies of Dealing with Taste and Odor Causing CompoundsExpand Existing Source Water Protection Efforts

Responses to the Drought of 2005 (continued)Initiate Phytoplankton Surveillance Program and Investigate In-Lake Treatment MethodsContinue Supplemental Water Supply ActivitiesUpdate Master Plan, including Blending OptionsCoordinate TMDL Plans with Drought Strategies and Emergency Plans

Source: Illinois State Water Survey,Center for Groundwater ScienceMahomet Aquifer

AcknowledgementsDave Stockton, Mayor, City of BloomingtonBloomington City Council, Tom Hamilton, City ManagerBrian Brakebill, Deputy City ManagerCraig Cummings, Director of WaterJill Mayes, Bloomington Water Treatment PlantDr. John OConnor, H2OC EngineeringDr. Jack Wittman, Wittman Hydro Planning AssociatesThe Staff of the Bloomington Water Treatment Plant and Water DepartmentOur Water Customers