By Jamie Vaughan, TU Great Lakes Engagement Coordinator and Bryan Burroughs, Michigan TU Executive Director
Introduction to the Water Use Advisory Council
The Great Lakes–Saint Lawrence River Basin Sustainable Water Resources Agreement of 2005 and Compact of 2008 require states and provinces bordering the Great Lakes to manage water resources responsibly. Michigan addressed this obligation by adopting Part 327 of the Natural Resources and Environmental Protection Act. Part 327 created a water withdrawal assessment program managed by the Department of Environment, Great Lakes, and Energy to prevent adverse resource impacts by water withdrawals on streams and rivers. The program requires registration for large-capacity water withdrawals (with a capacity of more than 100,000 gallons per day), creates an online process to streamline water withdrawal registration and authorization, and requires annual water use reporting and implementation of conservation measures.
Michigan’s Water Use Advisory Council (WUAC) is a statutorily created body of appointees established under Part 328 of the Natural Resources and Environmental Protection Act to study and make recommendations to executive and legislative branches regarding improving the state’s program for managing large-quantity water withdrawals. Trout Unlimited has participated in this body since 2007 with Michigan TU Executive Director as a current member. As Michigan trout streams depend on ample and stable groundwater input, the work of the council has significant implications for coldwater conservation and is paramount to TU’s mission.
Introduction to Report
The council reports its recommendations biennially, addressing needed improvements, changes, and investments in Michigan’s Water Use Program. The council’s 2020 recommendations received funding appropriations in 2022, and implementation of those recommendations is underway. These include many recommendations for new data, new data systems, integrated water management databases within the state, new modeling platforms, data gap analysis, and various water conservation initiatives.
The WUAC’s 2022 report presents high-priority recommendations to ensure sound and evidence-based management of Michigan’s freshwater resources. Among those recommendations are research and modeling of the downstream cumulative effect of water withdrawal throughout a watershed. Currently, the assessment models only predict withdrawal effects to the nearest stream reach, failing to account for the cumulative impact further downstream, leaving a glaring hole in the reliability of the assessments of adverse resource impacts, as required by law.
The report also recommends funding to develop a framework for predicting the negative impacts of withdrawals to inland lakes, another shortcoming of the current assessment tool. Regrettably, none of these recommendations received funding priority by the state in this year’s budget. Funding to support the WUAC 2022 recommendations was again not included in the Governor’s proposed budget for next year. There is a need to raise awareness for these recommendations and seek inclusion in legislative budget formation. The recommendations include the following:
Research Improving Water Withdrawal Assessment Tool Streamflow Depletion Allocations between Water Management Areas
Currently, the Water Withdrawal Assessment Tool (WWAT) uses an algorithm (sometimes referred to as the “half max rule”) to allocate the effects of a water withdrawal among the source Water Management Areas (WMA) and neighboring WMAs. The way the algorithm is currently applied generally only accounts for depletion to neighboring watersheds if the predicted depletion is at least half of the maximum depletion for any one watershed. This was done to help reduce non-sensical allocation from distant watersheds, but it can also leave significant depletions unaccounted for in other watersheds, increasing the chance for adverse impacts in the future. The question is how to more realistically apportion the streamflow depletions in the screening tool and for most site-specific reviews.
A refined method for accounting for factors that more realistically reflect the actual hydrogeologic landscape was developed and implemented. However, as currently implemented, the depletion allocation routine in the WWAT ignores all the calculated depletions that are less than half the maximum, resulting in the underprediction of the total depletion attributable to each proposed withdrawal. Also, the current method is not able to incorporate actual detailed spatial information about depletion amounts or extents. Recent advances in this field have provided better means to address this.
The depletion calculations were examined for 30 actual, registered wells in various hydrogeologic settings across the state. The calculated stream depletions were reviewed for all of the neighboring WMAs. Using the current algorithm (half max rule) in the WWAT, 74% of the total calculated depletions were included in the water accounting system (i.e., 26% of the total depletion amount was not accounted for). The range for individual wells was a high of 99% of the total depletion amount accounted for to a low of only 49% of the total calculated depletion accounted for.
This recommendation seeks to determine the feasibility of using a revised methodology in the WWAT screening tool and determine the results of applying the revised method to the entire database of registered large-quantity withdrawals. Additionally, it recommends the evaluation of any impacts on water availability as well as potential adverse resource impacts and, if so, identifying measures to mitigate the effects on registered users while avoiding adverse resource impacts. When findings are available, the WUAC will prepare recommendations on implementing the revised methodology.
Conduct Downstream Accounting Research + Evaluate Streamflow Depletion Effects Downstream Through a Stream Network
The current Michigan WWAT only estimates the local impact of surface water or groundwater withdrawals on streamflow and only alerts the user to withdrawals that might cause an adverse local impact. Streamflow depletion apparent in upstream parts of a stream network is hard to discern in downstream stream gage records. If upstream depletions propagate downstream without any compensation in the system or dissipation along the network, there is a potential for adverse impacts at downstream locations from accumulated upstream withdrawals that do not have direct local adverse impacts. This necessitates a watershed-scale accounting in the assessment.
Moreover, the water withdrawal assessment process is based on peak depletion rates. For intermittent withdrawals, the streamflow depletion may be attenuated such that the peak rate is reduced while its duration increases. This attenuation conserves the volume of water removed from the stream network and lessens the likelihood of adverse impact.
This recommendation proposes to complete an exhaustive literature review of existing research on observed or modeled downstream propagation of streamflow depletions, examine relationships between long-term changes in index flows and index flow yield (inches of runoff for the catchment divided by inches of precipitation in the catchment for an appropriate period) relative to climatic conditions at gaged streams throughout Michigan, and conduct literature review and empirical analyses to identify and provide underlying support for the proper spatial scale (WMA, entire upstream catchment of the WMA, or a lesser portion of the WMA’s catchment) for totaling cumulative withdrawals that potentially affect the index flow of each WMA.
After the downstream accounting research, the council would then recommend a series of modeling analyses to test mechanisms that would lead to attenuation of the stream depletion rates, identification of key features of the surface-water/groundwater system that help propagate or attenuate upstream depletion response, and identification of stream networks in the state that are more susceptible to upstream withdrawal and those that may be more buffered from upstream withdrawals.
The proposed research and evaluation are imperative to fully understand the cumulative downstream impacts of upstream withdrawals to make the necessary adjustments to WWAT and ensure proper protection of water resources from adverse resource impacts. Without this research and fix, the reliability of the WWAT to prevent adverse resource impacts is in question.
Develop an Inland Lakes ARI Conceptual Framework and Pilot Data Acquisition Assessment
This recommendation also relates to the cumulative downstream accounting problem within WWAT but in relation to its impacts on inland lakes.
The Natural Resources and Environmental Protection Act and Great Lakes Compact are predicated on protecting water-dependent natural resources from adverse impact, and the scope of this charge broadly includes water-dependent natural resources. At the point of creation and adoption of Part 327, a framework was developed for predicting the impact of water withdrawals on water-dependent natural resources, using stream fish communities as the indicator metric, and the science available at the time supported this framework development for rivers and streams. An analogous framework for inland lakes or wetlands was not feasible at that time. Due to this, Part 327 addressed impacts to inland lakes, not through predicted impact pathways to ecological components of those systems, but through general provisions focused on impacts to the human uses of inland lakes, through water withdrawals. In short, assessing adverse resource impacts for inland lakes has long been deficient.
Ever since, previous iterations of the WUAC have discussed obstacles and needs for creating an assessment framework for inland lakes that would function similarly to the stream-based system the water withdrawal assessment process relies upon now and be consistent with the scope and charges of the Great Lakes Compact. In recent years, new tools for efficient data collection regarding lakes have become available (lake-level instrumentation and crowd-sourced data platforms, water penetrating laser imaging, detection, and ranging (LIDAR), and lake source water isotope analysis), and new approaches to classifying lakes based on sensitivity to withdrawals have developed making this effort more feasible. The WUAC also reviewed and heard guest speakers from Wisconsin DNR present the findings of their approach for assessing impacts to inland lakes from water withdrawals. Further investigation on this topic is necessary, and several forms of support are now required to enable meaningful progress.
The WUAC has continuously investigated this issue and, in 2002, recommended a first initial financial investment required for the WUAC to make meaningful progress on this topic. This investment is not expected to produce a final acceptable framework for assessing adverse resource impacts for inland lakes but rather is needed to accomplish meaningful progress in the development of a first iteration conceptual framework and to conduct targeted data collection pilot projects so that meaningful future progress and developments are possible and this issue does not continue as unaddressed.
Conclusion
Michigan has an obligation as a signatory to the Great Lakes Agreement and Compact to manage its water resources responsibly. Unfortunately, current accounting frameworks fall short of the charge in numerous ways, risking missing or underrating adverse resource impacts on rivers, lakes, and streams. The WUAC’s report suggests an urgent need to research future data collection and modeling improvements to improve the Water Use Program’s ability to assess potential impacts of withdrawals more reflective of real-world processes.
The WUAC continues to urge the Legislature to approve financial allocations to support these activities, which will help Michigan fulfill its obligation to protect Great Lakes water resources for current and future generations and the ability of our state’s residents, businesses, anglers, farmers, riparian owners, river users, and utilities to access it sustainably.