Groundwater – Vital to Healthy Communities Steve Gaffield – Montgomery Associates Thomas Hovel...

Groundwater – Vital to Healthy Communities

Steve Gaffield – Montgomery AssociatesThomas Hovel – City of Fitchburg, WI

Madeline Gotkowitz – Wisconsin Geological Survey

Topics

• Groundwater basics & current issues

• Madison’s drinking water issues

• Fitchburg’s groundwater issues & approach

• Project examples from Fitchburg

• Discussion!

Wisconsin DNR

TravelWisconsin.com

The water cycle…

aquifer

recharge

Groundwater discharges to springs, streams and lakes

USGS Circular 1139 (1998)

Stream Baseflow

Lakes are the water table…

Wells intercept groundwater and diminish discharge to streams, springs and lakes

Pumping groundwater reduces discharge to surface water somewhere, always.

Changes to the water table and baseflow can be significant

Little Plover River, Portage County

May 2012

Clear Lake, Milton Wisconsin July 2009

Regional groundwater system: Madison, Fitchburg, Verona, Sun Prairie, Middleton, Monona, McFarland

Well 17

Monona Terrace

Upper aquife

r

Deep aquiferConfining unit

Low dissolved oxygen

High dissolved oxygen

Madison Water Utility Board Policies

Madison’s groundwater use 1960 - 2014

2008 water conservation goal: decrease 20% by 2020:73 gal/person/day → 58 gpd (now at 64 gpd)

63,000 wireless transmitters and water meters to comply with PSC requirements, in order to move to a conservation rate structure, ~ $12 M

Madison became the largest city in Wisconsin to offer a residential conservation rate structure

Cost of 4,000 gallons/month will increase 13% ($17.24 to $19.51)

Groundwater and Healthy Communities Planning Challenges

Planning Challenges

What is Important:

• Quality of life

• Health

• Environment

• Balance competing concerns• Resource-based neighborhood plans• Today, we are concentrating on one aspect important to

our way of life….

…water

Where is Fitchburg?

The Comprehensive Plan sets forth a long-range growth boundary of 50 years. Several Neighborhoods have been established to provide for future growth.

Completed Neighborhood Plans:• North Stoner Prairie (NSP)• McGaw• Northeast (NE)

Each Neighborhood has its own set of challenges arising from its unique natural features

NE—Ephemeral wetland

McGaw—S branch Swan Creek

NSP—Closed depression

Northeast Neighborhood

• Upper and lower aquifer

• Housing to the northeast built on hydric soils

Source: DCI map 9/18/2015

Photo from Ed Minihan

Northeast Neighborhood

Town of Dunn--Meadowview flooding

• Waubesa Wetlands a State Natural Area

• Spring flow• Calcareous fens• Nine Springs and Swan Creeks

Source: madmimi.com

Northeast Neighborhood

McGaw Neighborhood • Maintain stream flow in Swan Creek• Waubesa wetlands• Meet higher density desires & retain sufficient recharge, but be

concerned about higher groundwater levels

North Stoner Prairie Neighborhood

• Closed basin• Emergency pumping overflow• Groundwater mounding• Nine Springs Creek, spring flow

Closed depression flooding in June 2013 following 2” rainSource: MARS

Water recharged at NSPN will flow east-northeast toward Nine Springs Creek

Opportunity to enhance baseflow

Little risk of groundwater flooding to south

• Gradient to Nine Springs Cr is 5x higher than gradient toward Lake Harriett

• Groundwater follows path of least resistance & highest gradient

Source: SAA and MARS

North Stoner Prairie Neighborhood

Groundwater is an important resource

Balance between withdrawal and recharge

Stream base flow

Methods to how that can be accomplished is the next part of the presentation

Well zones of contribution Source: Dane Co Water Quality Plan

Evapotranspiration

Tree Canopy Interception

Surface Runoff

Natural

Urban Water Balance

Stormwater runoff

Developed

Low Impact Development

Stormwater infiltration

NE Neighborhood Plan

Glacial Deposits

Upper Sandstone Aquifer

Lower Sandstone Aquifer Eau Claire Shale

Bedrock surface

Lake Waubesa

City well cased through shale

Northeast Neighborhood

Granite

Urban Groundwater Balance

Groundwater Response

Modified from USGS

?

• Review available data• Install monitoring

wells• Simple analytical

equations• Computer models

(Bouwer, 2002)

(USGS, 2010)

Evaluating Groundwater Response

Northeast Neighborhood: Flooding Concerns

• Groundwater rise predicted if recharge increased.

• Plan designed to maintain existing recharge

• No rise expected

(RJN Environmental Services)

McGaw Neighborhood: Downstream Resources

• Computer model available

• Increase in recharge with stormwater infiltration

• Increased water supply pumping

McGaw

Where Does Groundwater Go?

McGaw

Partial Offset of Pumping Increase

• 2 in/yr recharge increase predicted

• Water demand scenarios: low, mod & high

• Streamflow losses limited to 1-5%

North Stoner Prairie Groundwater Concerns

Closed depression flooding

Basement flooding

Borings and Monitoring Wells

County Water Table Map

• Water table slopes east• Consistent with borings

& wells• Land rises to east• No flooding impacts

expected in adjacent neighborhood

• Recharge will benefit Nine Springs Creek

(WGNHS)

West: groundwater shallow

East: groundwater > 20 ft

“Take Homes”

• Groundwater is an important resource for people and nature.

• Groundwater should be considered in urban water management.

• Managing urban land use and groundwater requires a balancing act.

Why Bother?

• Drinking water quality and quantity

• Quality of life & property values

• Mental & social benefits of natural areas

• Physical & economic benefits

(American Rivers)

http://depts.washington.edu/hhwb/