Enhancing Groundwater Recharge g gfor Water Supply

H. Allen Wehrmann, P.E., P.H.(GW), D.WRE

Center for Groundwater ScienceCenter for Groundwater Science

Illinois State Water Survey

Northeast Illinois Regional Water Supply Planning GroupChicago, IL

November 25 2008November 25, 2008

Acknowledgments

Illi i St t G l i l S• Illinois State Geological Survey

• George Roadcap, Illinois State Water Survey

• Southeastern Wisconsin Regional Planning Commission (SEWRPC)

Key ConceptsKey Concepts

• Infiltration

• Groundwater RechargeGroundwater Recharge– Groundwater Recharge

– Aquifer Recharge

G d t Di h• Groundwater Discharge

• Recharge Zones

• Discharge Zones

• Local and Regional Flow SystemsLocal and Regional Flow Systems

DefinitionsDefinitions

• Infiltration – entry and associated downward flow ofInfiltration entry and associated downward flow of water from the ground surface into the unsaturated zone

• Recharge – advance of water into the saturated zone, associated with flow away from the water table and within the saturated zone

• Recharge to an aquifer – when water enters a h d h d f d fhydrostratigraphic unit defined as an aquifer as opposed to simply passing the water table

Groundwater, R.A. Freeze and J.A. Cherry, 1979. Prentice‐Hall, Englewood Cliffs, NJ.Natural Recharge of Groundwater in Illinois, Bruce Hensel, 1992.  Illinois State Geological Survey, EG142.

The Hydrologic CycleThe Hydrologic Cycle

Groundwater Rechargeg

Three Basic Elements of a Recharge System

WATER SOURCE

Surface Soil 

TransmissionDeep Vadose Transmissionand DeliverySystem

Deep VadoseZone

Recharge

Aquiferq f

Source: Daniel Stevens, Presentation to the Groundwater Resource Association of California, San Joes and SEWRPC. See also:SEWRPC Technical Report No. 43, http://www.sewrpc.org/watersupplystudy/documents.shtm

Factors Affecting f l d hInfiltration and Recharge

• Rainfall intensity and duration• Texture and permeability of soil/geologic materials• Soil moisture/depth to water table• Slope and landscape position• Land coverLand cover

– Vegetation (row crop, grasses, trees, etc.)– Impervious surface (building footprint, streets, driveways, sidewalks, 

parking lots, etc.)– Retention/detention basins

• Presence and type of water sources or sinks (e.g., leaky water supply pipes, storm sewers)

Natural Recharge of Groundwater in Illinois, Bruce Hensel, 1992.  Illinois State Geological Survey, EG142.

E l f S f I fil i T h l iExamples of Surface Infiltration Technologies

Source: Colorado Geological Survey, Department of Natural Resources and SEWRPC. See also: SEWRPC Technical Report No. 43, http://www.sewrpc.org/watersupplystudy/documents.shtm

Common Clogging Problems of a Recharge Basin

Source: Daniel Stevens, Presentation to the Groundwater Resource Association of California, San Joes and SEWRPC. See also:SEWRPC Technical Report No. 43, http://www.sewrpc.org/watersupplystudy/documents.shtm

Surface Recharge System with Permeable Vadose Zone

Source: Daniel Stevens, Presentation to the Groundwater Resource Association of California, San Joes and SEWRPC. See also:SEWRPC Technical Report No. 43, http://www.sewrpc.org/watersupplystudy/documents.shtm

Unsaturated zone

Water table

Unconfined AquiferUnconfined Aquifer

Increase aquifer saturated thickness/R d i t f d dReduce impacts of drawdown

Unsaturated zone

Water table

Unconfined Aquifer

Effect on confined aquifers?Effect on confined aquifers?

Unsaturated zone

Water table

Unconfined AquiferUnconfined Aquifer

Confining Layer

Confined Aquifer

Geologic Mapping Approachg pp g ppto Potential for Recharge

• Originally developed to predict likelihood of uppermost aquifers to contamination from surface or near‐surface sources

• Surrogate for estimate of aquifer recharge g q gpotential

• Screening tool for prioritizing resources andScreening tool for prioritizing resources and guiding planning (e.g., IEPA, Winnebago County Health Dept., McHenry County)County Health Dept., McHenry County)

Aquifer Sensitivity Map for Kane County

Source: Illinois State Geological Survey

Major jQuaternaryAquifersqin Kane County

Source: Illinois State Geological Survey

Kane County ModelKane County ModelGroundwater Recharge Zonation

2.2”/year2.2 /year

3.5”/year

11”/year

17.5”/year

Local/Regional Groundwater Flow Systemsg y

Layer16

Layer16

Layer16

Layer16

Layer16

Layer16

Layer16

Layer16

Layer16

Layer16

Layer16

Layer14

Layer14

Layer14

Layer14

Layer14

Layer14

Layer14

0Years

1Year

2Years

3Years

4Years

5Years

6Years

7Years

8Years

9Years

10Years

10Years

15Years

20Years

25Years

30Years

35Years40

YearsYearsYearYearsYearsYearsYearsYearsYearsYearsYearsYearsYearsYearsYearsYearsYearsYearsYears

Source: Illinois State Geological Survey

Water Quality Changes in Shallow Kane C P bli W S W llCounty Public Water System Wells140

C

100

120Carpentersville 5 Carpentersville 6 East Dundee 2 Patterson MHP 1 Sbdv Water Trust 1 3

(mg/

L) 80

South Elgin 4 South Elgin 5 Sugar Grove 2 Utl Inc Lake Marian Water Corp 3

Cl

40

60

0

20

1950 1960 1970 1980 1990 2000

SEWRPC Enhanced Recharge ProposalSEWRPC Enhanced Recharge Proposal

• Shallow aquifer recharge enhancement• Shallow aquifer recharge enhancement– Rainfall infiltration systems on environmental corridors ag land or other open landscorridors, ag land, or other open lands

– Groundwater recharge area protection/purchase

– Treated wastewater infiltration systems– Treated wastewater infiltration systems 

• Deep aquifer recharge enhancementI j ti f t t d L k Mi hi d i ki t– Injection of treated Lake Michigan drinking water 

Source: SEWRPC Planning Report No. 52, http://www.sewrpc.org/watersupplystudy/chapters.asp

SEWRPC AlternativeGroundwaterRecharge

RainfallInfiltration

~4 mgdg

Proposal EffluentInfiltration

11 mgd

Deep AquiferInjectionInjection9 mgd

Source: SEWRPC Planning Report No. 52, http://www.sewrpc.org/watersupplystudy/chapters.asp

Happy Thanksgiving!Happy Thanksgiving!

See you next month…