Bloomington’s Water Supply: System Overview and Planning

1. Bloomington’s Water Supply: System Overview and Planning by: Rick Twait, Superintendent of Water Purification City of Bloomington Mahomet Aquifer Consortium Meeting No. 56 October 22, 2007

7. Bloomington, IllinoisWater Utility • 77,000+ Customers • 75,000 City Residents • 2,200+ Customers from Villages and Public Water Districts • 11,400,000 Gallons Average Daily Pumpage • Approximately 80% Residential Consumption • BNWRD Discharges ~20 mgd

8. Bloomington’s Two Water Supply ReservoirsLake BloomingtonEvergreen LakeConstructed in 1929 Constructed in 1971Raised 5 feet in 1954 Raised 5 feet in 1995635 surface acres 900 surface acres8,760 acre-ft storage 15,480 acre-ft storage69.5 sq.mi. drainage area 41.1 sq.mi. drainage area70:1 drainage to surface area ratio 29:1 drainage to surface area ratio

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

15. Dry Spells to Droughts • In 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.”

16. Types of Municipal Water Shortages Supply Shortages Can be Caused by: • Drought • Demand • Quality: • Health (Regulatory) • Aesthetic

17. Types of Municipal Water Shortages (cont’d) Treatment Shortages Can be Caused by Inadequate: • Treatment Capacity • Transmission Capacity • Storage Capacity To Meet Demands

27. Bluegreen Algal Filament Heterocyst 400x

28. 400x

29. 1988-89 Drought • Water Problems • Extremely Low Reservoir Levels • Concerns about Getting Water to Pump Intakes • Extremely High Demands: • Decreased Treatment Efficiency • Plant Operated at Peak Capacity • Low Water Quality • Taste and Odor Episodes Frequent and Severe

30. 1988-89 Drought • Operational Responses • Water Restrictions • Lawn Watering • Water Served in Restaurants by Request • Taste and Odor • KMnO4 • CuSO4 • PAC • Purchase Floating Pumps

31. 1988-89 Drought • Planning/Supply Responses • F&W Long Term Water Study • Initiate Watershed Protection Program • Raise Evergreen Lake Spillway by 5 Feet • Build and Obtain Permit for Mackinaw River Pumping Pool • Raised Water Rates • Installed GAC Caps on Filters • Begin Planning and Investigation of Groundwater Source

32. 1988-89 Drought • Planning/Supply Responses (continued) • Expand Treatment Plant Capacity at Lake Bloomington • Construction of 2 MG Elevated Tank • Construction of Additional Transmission Main from Lake Bloomington to Town

33. Bloomington, Illinois Finished Water Nitrate Levels

34. Raising Spillway Elevation of Evergreen Lake Increased Capacity by 36%

36. Additional Watershed Area Due to Mackinaw River Pumping Pool

37. Drought of 2005 • Demand Hit Plant Capacity • Cool Period Limited Duration of Extreme Demand • Extra Capacity of Evergreen Lake Extended Days of Available Supply • Higher Reservoir Levels, GAC Caps, and Destratifiers Resulted in Fewer T&O Issues (initially)

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

39. Responses to the Drought of 2005 • Contracted with Wittman Hydro Planning Associates for Drought Response Plan and Draft Drought Ordinance • Performed Intensive In-House and Contracted Studies of Dealing with Taste and Odor Causing Compounds • Expand Existing Source Water Protection Efforts

40. Responses to the Drought of 2005 (continued) • Initiate Phytoplankton Surveillance Program and Investigate In-Lake Treatment Methods • Continue Supplemental Water Supply Activities • Update Master Plan, including Blending Options • Coordinate TMDL Plans with Drought Strategies and Emergency Plans

41. Mahomet Aquifer Source: Illinois State Water Survey, Center for Groundwater Science

45. Acknowledgements Dave Stockton, Mayor, City of Bloomington Bloomington City Council, Tom Hamilton, City Manager Brian Brakebill, Deputy City Manager Craig Cummings, Director of Water Jill Mayes, Bloomington Water Treatment Plant Dr. John O’Connor, H2O’C Engineering Dr. Jack Wittman, Wittman Hydro Planning Associates The Staff of the Bloomington Water Treatment Plant and Water Department Our Water Customers