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Groundwater Monitoring

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Our understanding of impacts groundwater quantity and quality are informed by ongoing monitoring efforts.  Portage County is involved in a number of different monitoring strategies that address different aspects of groundwater quality and quantity.  To learn more about each strategy please scroll down.  For recent groundwater level monitoring results please click on monitoring sites located on the map below.  To view monitoring sites on a mobile device, please click here. If you wish to become a citizen volunteer and assist with County monitoring efforts, please scroll to the bottom of the screen.



Groundwater Quantity Monitoring

U.S.G.S. Hydrograph Wells

Located within the and adjacent to Portage County are nine long-term groundwater level monitoring wells, referred to as "hydrograph well".  Portage County monitors three of these wells, as seen on the map above.

Tracking groundwater elevation over many years provides a way to understand the relative status of the water table across the County and provides a place to begin to understand the impacts of different types of development on groundwater resources over time.

Stream and Lake Level Monitoring 

In 2015, the Portage County Planning and Zoning Department in collaboration with Wisconsin Department of Natural Resources (WDNR), worked to establish a citizen water level monitoring program that monthly monitors stream baseflow and lake levels at sites chosen by UW- Stevens Point, WDNR, and Portage County.

The purpose of the monitoring project is to increase the number of monitored water bodies and monitoring frequency through a low-cost effort by engaging the resources of trained volunteers.  This data will help to show the current status of groundwater and surface water levels throughout the County in areas not previously monitored.  This program has not only been implemented in Portage County but in five other counties in the central sands region including Waushara, Wood, Waupaca, Marquette, and Adams.  All other counties have been collecting stream and lake levels since 2013 in the same exact manner as Portage County.  This program is implemented in two ways:

Lake Level Monitoring

Water can enter lakes from a variety of sources including groundwater, runoff from the watershed, surface waters (like streams and rivers) flowing into the lake, and direct precipitation into the lake. Water leaves lakes through groundwater or surface water flow and evaporation (Wisconsin lakes).

Lakes are classified based on how water enters and exits the lake. For some lakes, all or most of their water enters the lake through one source (such as groundwater), other lakes may receive water through several sources. Seepage lakes do not have an inlet or an outlet. As landlocked water bodies, the principal source of water is precipitation or runoff, supplemented by groundwater from the immediate drainage area. Due to their dependence on groundwater, water levels in these lakes may fluctuate seasonally and often reflect groundwater levels and precipitation patterns. Seepage lakes in Portage County are being instrumented with shallow driven point wells to monitor lake levels as a supplemental data source to local groundwater levels.

By monitoring local lake levels, we can contribute valuable baseline data to professionals to help better understand variation in groundwater levels and impacts on local lake due to groundwater use.

Lakes are instrumented with a shallow drive point monitoring well that will be installed by County staff close to the lake shoreline, above the ordinary high water mark, and on public property wherever possible, out of the way of lake users.  Volunteers conduct the monitoring and are guided by County staff to determine when measurements need to be taken (usually on a monthly basis).  Lake level monitors are to be trained by County staff.  Lake measurements are reported from the volunteers to the Portage County Water Resource Specialist, which will then be uploaded to the WDNR Surface Water Integrated Monitoring System (SWIMS) database, posted to the Portage County website and shared with the Town Boards and Portage county Groundwater Citizen Advisory Committee.  To improve accuracy of the volunteer efforts, lake levels will be audited by County staff.  Lakes currently monitored by citizens for lake levels in Portage County include Adams Lake, Bear Lake, Lake Emily, Lime Lake, Onland Lake, Rhinehart Lake, Thomas Lake, Sunset Lake, and Wolf Lake.  To view current results simple click on the sites on the map above.

Stream Base flow Monitoring

Water in a stream comes from three different sources.  A small amount comes from rainfall directly.  Larger amounts either come from runoff from rain events, or from groundwater flowing into the stream called baseflow.  Baseflow is defined as the sustained low flow of a stream due to groundwater inflow to the stream channel.  Groundwater flows into streams when the water table (top of groundwater saturation) rises above the streambed.  Perennial streams flow because groundwater remains above the streambed throughout the year.

Stream flow, or discharge, is the volume of water moving down a stream or river per unit of time and is commonly expressed in cubic feet per second (cfs).  Stream flow can be affected by humans.  In watersheds with high human impacts, base flow may be depleted by withdrawals for irrigation, domestic, or industrial purposes.  Groundwater is drawn away from the stream creating a decline in the amount of water that would otherwise flow to the stream.  The depletion of baseflow to the stream reduces flows overall, but reduced flows are more noticeable during dry periods and may leave little water for fish and other aquatic life.

The question of how big the human impacts are on central Wisconsin rivers and streams remain unanswered.  By meeting the goals of this project, baseflow monitoring can help professionals throughout the state answer this question.

Stream monitors are trained in small groups to gauge streams using velocity cross section methods.  Velocities are measured using Marsh-McBirney flow meters that were purchased for each County by WDNR.  Training on using the flow meter was provided by UWSP staff.  Volunteers conduct the monitoring and are guided by County staff to determine when measurements need to be taken (usually on a monthly basis).  Stream measurements are reported from volunteers to the Portage County Water Resource Specialist, which will then be uploaded to the SWIMS database, posted to the Portage County website and shared with the Town boards and Portage County Citizen Groundwater Advisory Committee.  To improve the accuracy of the volunteer efforts, stream flows will be audited by UWSP, contingent upon funding.  Streams/rivers currently monitored by citizens for stream base flow in Portage County include Allen Creek, Bear Creek, Bradley Creek, Buena Vista Creek, Ditch #4, Flume Creek, Plover River, Poncho Creek, South Branch of Ten Mile Creek, Stoltenburg Creek, and the Tomorrow River.

Groundwater Quality Monitoring

In the summer of 2017 Portage County began its first County-wide well water quality sampling project.  Portage County has partnered with the University of Wisconsin-Stevens Point o sample 229 wells throughout the County for basic water quality parameters including nitrate-nitrogen, pH, alkalinity, hardness, chloride, and conductivity.

To learn more about the project you can visit:

Citizen Volunteers

Monitoring efforts in Portage County would not be possible without the assistance of our many citizen volunteers!  Our volunteers measure both lake levels and stream base flows at sites throughout the County on a monthly basis.  Each volunteer is provided with training and the materials that they need.  If you are interested in becoming a volunteer to help with these efforts, please contact the Portage County Water Resource Specialist at the information below:

Jen McNelly, Portage County Water Resource Specialist