Questions from Minnesota State Agencies (Dept. of Natural Resources, Dept. of Health and Pollution Control Agency) on the Waukesha Diversion Proposal

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1 Questions from Minnesota State Agencies (Dept. of Natural Resources, Dept. of Health and Pollution Control Agency) on the Waukesha Diversion Proposal Questions and comments from Minnesota are in black. WDNR Responses are in blue. The following questions about the relate to these Compact and Agreement parts: Compact Section e and Agreement Article e This Exception should not be authorized unless it can be shown that it will not endanger the integrity of the Basin Ecosystem Compact Section and Agreement Article ensure that the proposal will result in no significant individual or cumulative adverse impacts to the quantity or quality of the Waters 1) According to the information in Table 22 on page 91 of the Technical Review, the Root is impaired for phosphorus along the majority of its length, and at low flows the effect of the new discharge may be substantial. Currently there is no established phosphorus TMDL for the Root, however it is on the WIDNR s draft 2016 Impaired Waters List. How will the new wastewater discharge impact the TMDL once the Root Impaired Waters Study is implemented and approved? There is no scheduled TMDL for the Root. When a TMDL is developed, the Applicant would be included in the process, and a wasteload allocation would be given to the existing discharge under an approved TMDL. Also, Wisconsin has a phosphorus implementation rule (NR 217, Wis. Admin. Code) that allows for a new discharge to an impaired water under certain conditions: a) it is part of a wasteload allocation or reserve capacity of an approved TMDL; b) the discharger can participate in water quality trading; or c) show an improvement to water quality. To ensure an improvement in water quality, the department drafted water quality based effluent limits for phosphorus, as low as to 0.06 mg/l, well below the water quality standard for the Root (0.075 mg/l). The median background concentration for phosphorus is approximately 0.1 mg/l in the Root upstream of the discharge location. In lieu of a TMDL, discharging at concentrations well below the water quality standard builds in a margin of safety and ensures an improvement in water quality concentrations for total phosphorus. 2) It is apparent that the Root has poor water quality and is heavily impacted by point and nonpoint sources of pollution upstream and downstream of the new discharge. How will the new discharge impact the 's biota? High phosphorus concentrations are associated impaired or impacted biological communities and, at low flow rates, additional water added to a stream are not always beneficial to the biota. Have flow / ecology relationships been explored in the Root or analogous Lake Michigan Tributary streams?

2 The Root is classified as a warm water sport fishery, and as noted in the response to question 1 and elsewhere, is listed as impaired for phosphorus and total suspended solids. Both positive and negative possible impacts to the flora and fauna of the Root are outlined in Wisconsin s preliminary final EIS (Section ). The treated wastewater from the Applicant s WWTP would be required to meet all WPDES requirements. This would result in higher quality water being discharged than the receiving water. An increased flow rate to the Root will provide for an increase in water depth and wetted perimeter, improving stream habitat during low flow conditions. An increase in flow will also improve fish spawning conditions. 3) The Technical Review document focuses on the impact of the new wastewater discharge on conventional pollutants such as phosphorus, sediment, and temperature. Other pollutants are also of concern, such as heavy metals, pharmaceuticals, and chemicals from personal care products. Are there plans for adapting the wastewater treatment protocol to address additional pollutants as they emerge? As part of the Wisconsin Pollutant Discharge Elimination System (WPDES) program permit application process, municipal wastewater treatment plants (WWTPs) must complete a priority pollutant scan every 5 years to comply Clean Water Act requirements ( which include heavy metals. The Environmental Protection Agency (EPA) is studying pharmaceuticals and personal care products, but there are no federal water quality standards for these substances. Therefore, neither Wisconsin nor any other state has water quality standards for pharmaceuticals and chemicals from personal care products. If EPA were to issue guidance or develop standards for these pollutants, WDNR would adapt them into state water quality standards, and update WPDES permits as necessary to comply Clean Water Act requirements. 4) What is the nature of the change to the Root s hydrograph from the additional water? To summarize flow impacts at 10.1 MGD, the Applicant updated Volume 4 of its application, Appendix K, Tables 3 (proposed discharge location) and 4 (Root Steelhead Facility). The Applicant used HEC-RAS model simulation results to create the tables, based on statistics from Milwaukee Metropolitan Sewerage District (MMSD) and USGS. The following table reflects an updated Table 3 which represents the Root at the return flow location (at downstream locations the impacts would be less): Root Scenario % in (%) in water depth (ft) % water depth (%) Avg Velocity (fps) Avg Velocity (fps) Low % % Year % % Year % %

3 10 Year % % Year % % Year % % Year % % Additional stream cross sections are in the City s Application Volume 4, Appendix K, Attachment A. Any flow up to 10.1 MGD to the Root would be less than the rise reflected in these cross sections, as the Applicant developed these cross sections for flows greater than the current return flow proposal. 5) Is the Root channel likely to be significantly altered from its natural state in terms of width/depth, sinuosity, slope, water conveyance capacity, or stream bank stability? For example, a change greater than 20% of bankfull flow could be considered significant. The department reviewed the Applicant s analysis that considered impacts to the Root channel from the additional flow. The Milwaukee Metropolitan Sewerage District completed a sediment transport study of the Root upstream of the outfall location in This study concluded that the river stability is relatively insensitive to changes in flows because of the erosion resistance of the channel boundary materials, the relatively low gradient, and the presence of a functional floodplain (see City of Waukesha Application, Volume 4, page 23). Channel changes listed in the question (width/depth, sinuosity, slope, etc.) would occur at higher flows. Based on hydraulic modeling results at the proposed discharge location, the 2-year flow would experience a 1.5% increase e due to the maximum ~15.6 cfs (or 10.1 MGD) return flow rate at the discharge location (about 0.5 inch increase in water depth). During a 100-year flow, the percentage of flow increase is 0.3% (0.2 inch increase in water depth). For any location downstream of the proposed discharge, flow would have even less of an impact. As the model results show very small percentages of flow increase, the department does not expect return flow to have significant negative impacts to the Root geomorphology. 6) How will the addition of water to the Root impact ice formation and is this an important factor for hydrological or biological connectivity? Ice formation may be impacted in the immediate vicinity of the proposed wastewater outfall location and downstream dependent generally on the temperature of the effluent, design of the outfall, channel width, water velocities, receiving water temperature, etc. The interplay of these factors is complex, but in general, they can be simplified here to the observation that the Root in the project area is a low-gradient run, given to the formation of surface ice starting approximately in December. Ice in flowing streams generally takes three forms frazil ice, anchor ice, and surface ice. Frazil ice refers to tiny ice particles and resulting conglomerates (clusters) that develop in the water column, and are produced by super-cooling. At slower flow velocities (below 0.9 m/s), frazil ice may accumulate at the surface as floes and contribute to the development of surface ice. Frazil ice has

4 been shown to abrade fish gills, and where velocities are high, contribute to anchor ice formation. Anchor ice is the formation of ice on the river bottom, created under super-cooling conditions either from frazil ice conglomerates collecting on the river bottom or from in-situ ice development. Anchor ice typically forms in turbulent waters such as in riffles or in high gradient areas. In some cases, anchor ice can alter river bed elevations and thus water elevations, and can freeze aquatic macroinvertebrates in their gravel beds. Additionally, anchor ice can increase bed erosion, as releasing anchor ice during thaw events may take bottom substrate it. Finally, surface ice is ice that forms on the water surface due to atmospheric heat loss and generally forms in low-velocity areas (below 0.6 m/s). Surface ice acts as insulation to its underlying water, keeping mean water temperatures above freezing and preventing the creation of frazil and anchor ice. Surface ice is the only ice that has been documented by department staff in the Root. The addition of treated wastewater to the Root may impact surface ice. At the proposed outfall and proceeding downstream, warmer water temperatures may create an open water situation until the river is sufficiently cooled as to contribute to the development of surface ice. The majority of the Root downstream of the proposed outfall downstream to County Line Road is a shallow to medium-deep run. The general lack of riffles and shallow river gradient in this area should promote surface ice formation, as river velocities here are typically below 0.6 m/s and presents a smooth thermal transition and constant area for river cooling to take place. The proposed return flow to the Root may increase surface water elevations to a marginal degree downstream of the outfall, and correspondingly, the average height of surface ice may be higher when compared to historical conditions. d open water in a diminishing area proceeding downstream of the outfall, as well as increased water temperatures in this area, may attract aquatic biota and act as a refuge during extreme freeze events. Biological connectivity downstream of the outfall will likely not be impacted directly by ice creation, as the conditions favoring the two types of ice that would have the most impact on aquatic biota (frazil and anchor ice) will not be favorable and have not been observed on the Root. The following questions about the Alternatives Analysis relate to this Compact Section d. and Agreement Article d. There is no reasonable water supply alternative 1) Could there be other combinations of alternatives that have not been evaluated that could provide reasonable and feasible water supplies to Waukesha? The City of Waukesha and department s review of water supply alternatives was thorough. The department spent considerable time reviewing the City of Waukesha s reports, asking additional questions and evaluating the broad range of water supply alternatives and the more detailed review of the alternatives presented in Technical Review Section S2. The department believes that the analysis provided for the six water supply alternatives identified that there is no reasonable water supply alternative based on projected environmental impacts to the Mississippi basin. 2) The alternatives evaluated are dismissed due to various modeled impacts to surface waters. Was actual field collected data used to run the models? Were any of the modeled results field-checked? The department used an existing USGS model that was built using field data specifically to understand the feasibility of river bank inducement wells as a water supply alternative along the Fox in southeastern Wisconsin. The details of the model construction and calibration are in the report titled Development and Application of a Groundwater/Surface-Water Model using

5 MODFLOW-NWT for the Upper Fox Basin, Southeastern Wisconsin USGS Scientific Investigations Report The USGS calibrated the model results using measured water levels and stream flows. The department did not collect any additional data prior to running the model, as the model was fully developed, calibrated, and is representative of current conditions. The department s model scenarios are for hypothetical future groundwater drawals and cannot be field checked unless the modeled pumping actually occurs. 3) (provided by through Secretariat) What would the groundwater model results for stream flow depletion be if the return flow from the wastewater treatment plant was included (EIS pg 235)? The department provided an analysis of the Fox flows for the different water supply alternatives taking into account the return of wastewater to the Fox in the preliminary final EIS, Appendix A: Impacts to the Fox under different alternatives, starting on page 223. This analysis describes the assumptions used to determine the estimated baseflow reduction for each alternative. Please see table 7-1 in Appendix A, EIS page 224, for the percent change from the current baseflow for each of the alternatives discussed in the EIS.