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

Urban-Rural Growth, 1950-2000McLean County, Illinois

Year

1940 1950 1960 1970 1980 1990 2000 2010

Po

pu

lati

on

0

20000

40000

60000

80000

100000

120000

Urban (Bloomington/Normal)

Rural (All other Areas)

Source: U.S Census of Population, 1950-2000McLean County Regional Planning Commission

Bloomington, IllinoisWater Rates per 100 Cubic Feet

Cubic Feet Purchased per Month

First 2,300 Next 11,700 Next 486,000 Over 500,000

Wat

erR

ate

(Do

llars

/10

0 cu

bic

Fee

t)

1.80

2.00

2.20

2.40

2.60

2.80

3.00

3.20

RatePer100Ft3 InsideCity

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

Bloomington’s Two Water Supply ReservoirsBloomington’s Two Water Supply Reservoirs

Lake BloomingtonLake Bloomington Evergreen LakeEvergreen Lake

Constructed in 1929Constructed in 1929 Constructed in 1971Constructed in 1971Raised 5 feet in 1954Raised 5 feet in 1954 Raised 5 feet in 1995Raised 5 feet in 1995

635 surface acres635 surface acres 900 surface acres900 surface acres8,760 acre-ft storage8,760 acre-ft storage 15,480 acre-ft storage15,480 acre-ft storage

69.5 sq.mi. drainage area69.5 sq.mi. drainage area 41.1 sq.mi. drainage area41.1 sq.mi. drainage area70:1 drainage to surface area ratio70:1 drainage to surface area ratio 29:1 drainage to surface area ratio 29:1 drainage to surface area ratio

Lake Bloomington and Evergreen Lake Stage-Volume Curves:Hanson Engineers, 1999 data

Cumulative Volume (acre-feet)

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000110001200013000140001500016000

Ele

vatio

n (f

t abo

ve m

sl)*

675

680

685

690

695

700

705

710

715

720

725

Evergreen LakeLake Bloomington

Bloomington, IllinoisHigh Service Pumpage

Year

1980 1985 1990 1995 2000 2005

Hig

h S

ervi

ce P

umpa

ge(m

illio

n ga

llons

per

day

)

0

5

10

15

20

25

Average for Month

Bloomington, IllinoisHigh Service Pumpage

Year

1980 1985 1990 1995 2000 2005

Hig

h S

ervi

ce P

umpa

ge(m

illio

n ga

llons

per

day

)

0

5

10

15

20

25

Average for Month12 Month Running Average

Bloomington, IllinoisHigh Service Pumpage

Year

1980 1985 1990 1995 2000 2005

Hig

h S

ervi

ce P

um

pag

e(m

illio

n g

allo

ns

per

da

y)

0

5

10

15

20

25

Average for Month12 Month Running AverageMaximum Day for Month

Dry Spells to DroughtsDry Spells to Droughts

In In Detecting Drought Conditions in IllinoisDetecting Drought Conditions in Illinois Changnon (1987): Described Changnon (1987): Described Meterological, Agricultural, Hydrological, Meterological, Agricultural, Hydrological, and Economic Drought Conditionsand Economic Drought Conditions

US Drought Monitor (website): Describes US Drought Monitor (website): Describes conditions in terms from abnormally dry to conditions in terms from abnormally dry to exceptional drought, agricultural and/or exceptional drought, agricultural and/or hydrologichydrologic

Dry Spells to DroughtsDry Spells to Droughts

In In Drought Response Plan, City of Bloomington, Drought Response Plan, City of Bloomington, Illinois Water Department, Illinois Water Department, Wittman (2006) Wittman (2006) proposed a practical definition of drought for proposed a practical definition of drought for municipal water systems as:municipal water systems as:

““A reduction in precipitation or aquifer recharge A reduction in precipitation or aquifer recharge that affects the ability of the public water system that affects the ability of the public water system to meet the demands of the customers or to meet the demands of the customers or causes regulatory or aesthetic reductions in causes regulatory or aesthetic reductions in water quality.”water quality.”

Types of Municipal Water Types of Municipal Water ShortagesShortages

Supply Shortages Can be Caused Supply Shortages Can be Caused by:by:

DroughtDrought DemandDemand Quality:Quality:

• Health (Regulatory)Health (Regulatory)• AestheticAesthetic

Types of Municipal Water Types of Municipal Water Shortages (cont’d)Shortages (cont’d)

Treatment Shortages Can be Caused by Treatment Shortages Can be Caused by Inadequate:Inadequate:

Treatment CapacityTreatment Capacity Transmission CapacityTransmission Capacity Storage CapacityStorage Capacity

To Meet DemandsTo Meet Demands

Lake Bloomington Water Levels and Precipitation

Year

89 90 91 92 93 94 95 96 97 98 99 00

Ele

vatio

n (f

t abo

ve m

sl)

700

705

710

715

720

725

Pre

cipi

tatio

n (in

)

01234567891011121314151617181920

400x

Heterocyst

Bluegreen Algal Filament

400x

1988-89 Drought1988-89 Drought

Water ProblemsWater Problems Extremely Low Reservoir LevelsExtremely Low Reservoir Levels

• Concerns about Getting Water to Pump Intakes Concerns about Getting Water to Pump Intakes Extremely High Demands:Extremely High Demands:

• Decreased Treatment EfficiencyDecreased Treatment Efficiency• Plant Operated at Peak CapacityPlant Operated at Peak Capacity

Low Water QualityLow Water Quality• Taste and Odor Episodes Frequent and SevereTaste and Odor Episodes Frequent and Severe

1988-89 Drought1988-89 Drought

Operational ResponsesOperational Responses Water RestrictionsWater Restrictions

• Lawn WateringLawn Watering• Water Served in Restaurants by RequestWater Served in Restaurants by Request

Taste and Odor Taste and Odor • KMnO4KMnO4• CuSO4CuSO4• PACPAC

Purchase Floating PumpsPurchase Floating Pumps

1988-89 Drought1988-89 Drought

Planning/Supply ResponsesPlanning/Supply Responses F&W Long Term Water StudyF&W Long Term Water Study Initiate Watershed Protection ProgramInitiate Watershed Protection Program Raise Evergreen Lake Spillway by 5 FeetRaise Evergreen Lake Spillway by 5 Feet Build and Obtain Permit for Mackinaw River Pumping Build and Obtain Permit for Mackinaw River Pumping

PoolPool Raised Water RatesRaised Water Rates Installed GAC Caps on FiltersInstalled GAC Caps on Filters Begin Planning and Investigation of Groundwater Begin Planning and Investigation of Groundwater

SourceSource

1988-89 Drought1988-89 Drought

Planning/Supply Responses (continued)Planning/Supply Responses (continued) Expand Treatment Plant Capacity at Lake Expand Treatment Plant Capacity at Lake

BloomingtonBloomington Construction of 2 MG Elevated TankConstruction of 2 MG Elevated Tank Construction of Additional Transmission Main Construction of Additional Transmission Main

from Lake Bloomington to Townfrom Lake Bloomington to Town

Bloomington, Illinois Finished Water Nitrate Levels

0

5

10

15

20

25

30

35

01

/14/8

3

01

/14/8

4

01

/14/8

5

01

/14/8

6

01

/14/8

7

01

/14/8

8

01

/14/8

9

01

/14/9

0

01

/14/9

1

01

/14/9

2

01

/14/9

3

01

/14/9

4

01

/14/9

5

01

/14/9

6

01

/14/9

7

01

/14/9

8

NO

3-N

(m

g/L

)

Lake Bloomington and Evergreen Lake Stage-Volume Curves:Hanson Engineers, 1999 data

Cumulative Volume (acre-feet)

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000110001200013000140001500016000

Ele

vatio

n (f

t abo

ve m

sl)*

675

680

685

690

695

700

705

710

715

720

725

Evergreen LakeLake Bloomington

Raising Spillway Elevation of Evergreen Lake Increased Capacity by 36%

Additional Watershed Area Due to Additional Watershed Area Due to Mackinaw River Pumping PoolMackinaw River Pumping Pool

Drought of 2005Drought of 2005

Demand Hit Plant CapacityDemand Hit Plant Capacity Cool Period Limited Duration of Extreme Cool Period Limited Duration of Extreme

DemandDemand Extra Capacity of Evergreen Lake Extra Capacity of Evergreen Lake

Extended Days of Available SupplyExtended Days of Available Supply Higher Reservoir Levels, GAC Caps, and Higher Reservoir Levels, GAC Caps, and

Destratifiers Resulted in Fewer T&O Destratifiers Resulted in Fewer T&O Issues (initially)Issues (initially)

Drought of 2005Drought of 2005

Pumping Pool: From late December 2005 Pumping Pool: From late December 2005 through April 2006: 364 million gallons through April 2006: 364 million gallons pumped (over a month’s supply at average pumped (over a month’s supply at average usage) despite no/minimal runoff to lakes usage) despite no/minimal runoff to lakes from tributariesfrom tributaries

Extra capacity of Evergreen Lake Extra capacity of Evergreen Lake Reservoir resulted in more reserve Reservoir resulted in more reserve capacity at start of droughtcapacity at start of drought

Responses to the Drought of 2005Responses to the Drought of 2005

Contracted with Wittman Hydro Planning Contracted with Wittman Hydro Planning Associates for Drought Response Plan Associates for Drought Response Plan and Draft Drought Ordinanceand Draft Drought Ordinance

Performed Intensive In-House and Performed Intensive In-House and Contracted Studies of Dealing with Taste Contracted Studies of Dealing with Taste and Odor Causing Compoundsand Odor Causing Compounds

Expand Existing Source Water Protection Expand Existing Source Water Protection EffortsEfforts

Responses to the Drought of 2005 Responses to the Drought of 2005 (continued)(continued)

Initiate Phytoplankton Surveillance Initiate Phytoplankton Surveillance Program and Investigate In-Lake Program and Investigate In-Lake Treatment MethodsTreatment Methods

Continue Supplemental Water Supply Continue Supplemental Water Supply ActivitiesActivities

Update Master Plan, including Blending Update Master Plan, including Blending OptionsOptions

Coordinate TMDL Plans with Drought Coordinate TMDL Plans with Drought Strategies and Emergency PlansStrategies and Emergency Plans

Source: Illinois State Water Survey,Center for Groundwater Science

Mahomet Aquifer

AcknowledgementsDave 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