The Case for Twin Lakes

The Village of Roberts, and the WI DNR, are responsible for the damages to Town of Warren infrastructure, as well as losses and damages to personal property that residents of the Town of Warren have suffered, and continue to suffer as the result of the long-term rising water level trend that has lead to current chronic flooding conditions of Twin Lakes.

The Village of Roberts Public Works department pumps water from the deep Jordan aquifer using two high capacity wells, and supplies it to residents of the Village. It then treats the returned wastewater and discharges the effluent to the surface waters of Twin Lakes.  The Village operates its wells and wastewater treatment plant (WWTP) under permit by the Wisconsin DNR.  The treatment plant began the continuous discharge of wastewater into the lakes in 1962.

Since that time, the continuous flow of wastewater from the treatment plant, when combined with the other natural sources of water that flow into the lakes, has been exceeding the natural capacity of the lakes to dissipate the volume of water entering into them.  The result has been a very slow, but consistent, rising water trend in Twin Lakes that reached a critical damage point in 2015,  and continues to rise.  This trend has been accelerated in recent years by above average rainfall, and largely masked over the long term by the naturally occurring wide annual variations in lake level.  

Utilizing a comprehensive groundwater flow study published by the USGS in 2009, the effects of the WWTP wastewater augmentation to natural lake inflows can be accurately assessed.  The resulting data model presents a clear and startling visualization of the long term impact to the lakes that is directly attributable to the WWTP outfall.  Calculations driven by the data model precisely match the observed lake levels over the 43 year period between 1974 and 2017, and agree with estimates published by the DNR in 1995.

A review of the body of public documents related to the water treatment plant and its discharge of wastewater into the lakes under the WPDES permit issued by the DNR, shows that there has been a significant history of concern related to the impact of the volume of effluent outfall on the lakes.  Aggregation of the information published by the DNR over the years establishes that both the DNR, and the Village of Roberts, have had constructive knowledge of the detrimental effects of the WWTP effluent volume on Twin Lakes, but have adopted a position of willful blindness of the problem rather than acknowledging and dealing with the unpleasant facts.  

Despite that its own documentation indicates a clear history of concern, the DNR maintains that it is not legislatively authorized to regulate water quantity, and therefore has no involvement in lake level issues.  The Village of Roberts maintains that it is forced to comply with the requirements imposed by the DNR, has no other alternatives, and has refused to consider the possibility that long term WWTP effluent has significantly impacted the hydrology of the lakes.  

Both entities are further willfully blinded to the facts due to their strong desire to implement the State’s first installation of the CLEARAS water treatment system.  The DNR sees CLEARAS as a solution for phosphorus treatment all across the State, and has effectively made it the only alternative for the Village or Roberts to meet its quality targets under the requirements of its WPDES permit.  The Village is blinded by its lack of alternative discharge options, and the ramifications of acknowledging that its treatment plant has been the main contributing factor to the long term damage to the lake system, Town of Warren infrastructure, and personal property of residents around the lakes.

Ultimately, it is the residents of Warren / Roberts who will bear the burden.  Warren residents are directly affected by what is essentially a taking of their property as willfully blind government agencies simply allow the wastewater to expand the lakes.  Roberts residents will bear the near-term steep utility rate increases associated with the $2-3 million price of implementing CLEARAS, likely through a 20 year municipal bond, and then the long term costs associated with having to deal with the larger future problem of the impacts of the wastewater volume on the lakes and community.  

The true, long term, sustainable solution to this problem, as well as similar problems that other municipalities in the County have in dealing with their own waste, is to create larger, regional waste treatment infrastructure that allows Village of Roberts to have an alternative to discharging wastewater into Twin Lakes.

In the near term, affected residents will continue to struggle with trying to overcome the willful blindness being demonstrated by both the Village of Roberts, and the State DNR.  


The Timeline


The Water Treatment Plant originally began discharging treated wastewater from the Village of Roberts in 1962.


The DNR published the “Twin Lakes / Roberts WWTP Water Quality Assessment” in November 1995. This document states:

“The Roberts WWTP is estimated to contribute about 4% of the annual surface flow (or about 0.4 feet in lake level) during an average year” – p7

The conclusion reached in this report was that :

The overall hydraulic impact of this continuous source of water is unknown” -p15.  

This report recommends further study, and lists continuous lake water level measurement in both East and West Twin as the first required observation:

“1. Measure water levels in both East and West Twin Lakes using continuous recording equipment” – p19

The final recommendation is that “additional monitoring should be conducted” (-p20), and

Appendix 1 in the same document establishes a recommended measurement protocol, which calls for lake level measurements to be made at a minimum frequency of weekly.


In 2004, an Environmental Assessment (EA) was required by the DNR as part of a new joint facility plan combining the Village of Roberts with the Village of Hammond.  This assessment shows that effluent discharge impact on lake levels was a concern, as evidenced in these excerpts from the document:

“Given the limited value of past efforts to determine the factors influencing water levels in these lakes, and the dynamic nature of their hydrology, predictive modeling of its tendencies is not practical. The DNR proposes to address this issue by requiring, as part of this project, monitoring of wastewater flows, lake levels and wetland vegetation. If increases in water levels attributable to the outfall occur, it would occur gradually allowing time for effects to be assessed and mitigative measure to be taken.” -p13

Due to the extreme, natural water level fluctuation experienced by all local waterbodies, predictive modeling of lake hydrology is not possible without a very long data collection period. In recognition of the unknowns associated with this situation and the inability to do predictive modeling, a data collection effort including both biological and water level information will be incorporated into facility plan approvals and WPDES permits.

The two key points from this statement are: The DNR indicated they had no means to predictively model lake hydrology in 2004; They also stated that a data collection effort including water level information would be included in facility plan approvals and WPDES Permits.  Like the 1995 study, the 2004 Environmental Assessment also calls for monitoring of lake water levels to detect adverse effects over time. The 2004 EA also states:

A Detailed functional assessment of the Twin Lakes wetland systems will be conducted as part of the facility plan for the Town of Roberts.  This data will serve as baseline information should future problems develop regarding water level effects” -p12

This is a clear indication that there was significant concern related to the effects that the WWTP was having on lake level.  The concern was significant enough for the DNR to require a detailed surface water / groundwater interaction study, as part of the WPDES permit, and approved a plan for in August of 2007.  The EA goes on to recognize that the WWTP may raise lake levels, and that the lakes may expand along with the growth of the Village:

“The increased volume of water going into the lakes from the proposed expanded discharge has the potential to raise lake levels above those historically documented” -p13

“The only shorelands that might be affected by this project would be the shores of East and West Twin Lakes.  As stated above, the existing shoreline of the Twin Lakes might expand as the Village of Roberts Grows and the discharge rate increases” -p14


In August of 2007, the DNR approved a plan for the “Twin Lake Groundwater/Surface Water Interaction Study”, which it required as part of the Village of Roberts WPDES Permit.  The study took place during the full year of 2008, and the results published by the contractor in early 2009.  During the 2008 study, the elevation of West Twin Lake was measured and recorded to be 965.08 ft. No other official lake level observations have been recorded / published despite the DNR indicating it would require them as part of plan approvals and WPDES permits.  


In 2009, the USGS published “Simulation of the groundwater-flow system in Pierce, Polk, and St. Croix Counties,Wisconsin” U.S. Geological Survey Scientific Investigations Report.  This report contains a fairly detailed analysis of the hydrology of Twin Lakes, which indicates that the Roberts WWTP contributes 10% of the overall volume of water entering the lakes.  It establishes the predictive modeling tool that the DNR did not have access to in 2004.    The report suggests a focused field investigation be completed to enhance the results from the 2008 Groundwater / Surface Water interaction study:

“Application of the demonstration model of groundwater/lake-water interaction near Twin Lakes near Roberts, WI, could be enhanced through a focused field investigation of local hydraulic gradients and water-budget components for the lake.  Calibrating the model to these new data would decrease uncertainty in simulated results. Calibrated results could be used to (1) evaluate influences from climatic variability (seasonal to decadal) and augmentation on lake-water levels, and (2) estimate individual components of a nutrient budget for the lakes when combined with water-quality data.” -p37

This is another indicator of concern regarding the effects of WWTP water augmentation, the significant effects of which were already being observed by the time the 2008 Study was done.

2014 – 2017

Accelerated by the the above average rainfall the region experienced in 2014, 2015, and 2016 the lake stage reached a damaging level beginning in the spring of 2015, and continued to rapidly rise flooding roads, damaging homes, and causing the Town of Warren to declare a State of Emergency due to the flooding. Roads had to be raised a total of 5 feet in 2016 and 2017 in order to keep them above the water. In summer of 2017, Town of Warren residents affected by the water organized into Friends of Twin Lakes (FOTL), an unincorporated nonprofit association. The mission of Friends of Twin Lakes is to research and identify the cause of the flooding of the lakes, and advocate for solutions.

FOTL used the 2009 USGS simulation study, along with actual recorded rainfall, evaporation, and wastewater effluent data to create a data model and graph the expected behavior of the lakes. It published the findings in  “The Twin Lakes Story” in August of 2017. The resulting calculations precisely match the observed lake elevations made in 1974, 2008, and 2017.  The modeled impact of the WWTP effluent outfall on the lake levels also precisely matches the .4 ft (4.8 in) average rise the DNR attributed to the WWTP in 1995.

To validate the use of the 2009 USGS Study in creating the data model, the results were sent to hydrologist Paul Juckem, the author the study.  His response stated:

“…your use of a water budget model matches the general approach that we frequently use to evaluate historical lake water levels across the country.  … it’s encouraging that your modeled water levels match measured water levels.” – Paul Juckem via email Sept. 2017

This is a good testament that the work is on the right track, and reasonably accurate.


The next challenge for Friends of Twin Lakes will be to locate a qualified legal advocate to provide guidance on a course of action.  Time is of the essence, since we know that we can expect another .4ft of average lake rise in 2018, and every year into the future.  While we may get a reprieve depending on the rainfall, this problem will not be resolved without legal, and / or legislative action.