Don’t Repair the Estabrook Dam
Taking issue with Urban Milwaukee's series. First of two parts.
Removing the Milwaukee River Estabrook Dam is the most cost-effective and environmentally sound dam management alternative. That was the conclusion Milwaukee County’s consultant AECOM came to in a detailed 2015 environmental assessment. AECOM’s comprehensive assessment studied the socio-economic and environmental benefits and costs associated with repairing or removing the dam, and a number of other alternatives that were developed as potential compromises to accommodate the concerns of dam repair and removal proponents. Several public meetings were held over the last few years, and the public weighed in with support for dam removal. In addition, the cities of Milwaukee and Shorewood and the Milwaukee Metropolitan Sewerage District (MMSD) have all passed resolutions in support of dam removal.
It is unfortunate that Supervisor Theodore Lipscomb, Sr., who was present at early meetings for the County’s own expert assessment and had ample opportunity to review the assessment, failed to offer it to the full County Board for review and debate after public hearings in 2014 and after the draft environmental assessment was issued in summer 2015. In fact there has never been a standalone up or down vote at the Milwaukee County Board level based on the independent merits of this issue. This simple act could have avoided the political gamesmanship that followed, where the County’s policy was changed from repair, to removal, and then back to repair with fish passage through several budget cycles in 2014-2016 using questionable methods.
Some of the information cited by David Holmes from the draft September 2014 Environmental Assessment (EA) is outdated (e.g., dam management costs). Unfortunately, even the most recent EA must go through yet another revision because of the County Board’s change in policy to add fish passage to the repair of the dam, and to comply with the DNR’s requirement to establish an Operational Order for operating and maintaining the dam and fishway, and setting water levels that are protective of the public interest and the environment. A Public Hearing is tentatively planned in March 2016. I encourage all interested residents to follow and participate in the process and review the most recent October 2015 environmental assessment.
Milwaukee County’s current policy to repair the Milwaukee River’s Estabrook Dam and to construct an engineered fish passage facility around it should be postponed. The County should appoint an ad hoc committee of scientists and other independent professionals to review the existing information and provide recommendations that benefit the entire stakeholder group. Scientists and engineers from local universities and colleges, and water resource management agencies with expertise in surface water resource studies and management should be asked to participate on the committee. An alternative can be identified that mitigates the severe historical environmental impacts of deepening and widening of the river channel for 1.5 miles and the construction and operation of the Estabrook Dam. Unlike the dam repair with fish passage alternative, there are alternatives that are less costly, more sustainable, approach the historic functions and uses of the Milwaukee River, and do not increase potential flood and drainage damages. As in the past, the findings and recommendations should be presented to the public for review and input. Supervisor Lipscomb, as well as proponents and opponents to repairing the dam, should accept those recommendations as expertly informed and follow them without political maneuvering. What could be more responsible than that? After all is said and done, the ultimate decision on the fate of the Estabrook Dam will affect existing and future generations and will dramatically influence hundreds of square miles within the Milwaukee River and Lake Michigan Basins, an area dwarfing the confines of the 103-acre impoundment. It’s important the County and its residents make that decision based on the best information available.
That said, here is some of my relevant background. I am a former water resources and fisheries biologist with the Wisconsin Department of Natural Resources (DNR) having retired in July 2015 after 38 years with the agency. My experience as it relates to the Estabrook Dam included working with over 15 dam owners and stakeholders to assess dam management alternatives in the Milwaukee River Basin, the pre- and post-monitoring of those projects, as well as assisting with the design of fish passage features including the fishways at the Mequon-Thiensville Dam on the Milwaukee River and several projects along the Menomonee River. I was also the local DNR project manager for the $4.7 million North Avenue Dam removal completed by the City of Milwaukee in 1997, and was also involved with the initial assessment that identified the extent of sediment accumulation and PCB contamination in the Milwaukee River’s Estabrook Dam impoundment. I am a long-time, taxpaying resident of Milwaukee County and deeply care for what is best for the long-term uses and values of the Milwaukee River.
The following is a very brief summary of a longer and more in-depth analysis with exhibits and links regarding the future state of the Estabrook Dam and impoundment, which can be found here. I would appreciate your review of the larger document and offer your comments by way of this article.
What was the Milwaukee River’s historic morphology? Drainage Lake or River?
Mr. Holmes and supporters for repair of the dam argue that keeping the Estabrook Dam restores the “…unique hydrologic feature – a drainage lake that appears to have existed in the area of Lincoln Park since before the end of the Wisconsin glaciation.” Firstly, the historic river morphology that surrounded the area is not unique to the Milwaukee River watershed. There are numerous examples of similar river reaches in Milwaukee, Ozaukee and Washington Counties, some have been altered and others remain in a relatively natural state. Secondly, by many abiotic or biotic measures, the pre-European settlement of the Milwaukee River surrounding the Estabrook Dam and its impoundment was riverine and supported river ecological functions and values. This is borne out by Milwaukee County’s GIS-based 1937 aerial photographs that were taken while half of the river channel modifications downstream of Hampton Ave. were still under construction, and prior to constructing the dam and the river “center-cut” upstream of Hampton Ave., as well as from historic planning documents.
Prior to the 1930’s lowering of the rock outcrop and construction of the 0.4 mile long “center cut” between Hampton Avenue and the upper confluence of the present day “east and west oxbows”, the Milwaukee River was a low-gradient, meandering alluvial river channel dominated by pool and run features. Its immediate corridor and broad floodplain included over 100-acres of floodplain wetlands that supported habitat for a diverse plant and animal community sustained by seasonal flood waters that deposited nutrient-laden sediment. The top of the bank was reported to be only 2-feet from the normal (base-flow) water surface suggesting the entire river valley was inundated during frequent floods. The flood waters likely extended upstream into additional wetlands along “Mud Creek” (present day Lincoln Creek).
All rivers transport water and sediment. The physical, chemical and biological functions of a river’s ecosystem depend on this process. Unlike a “drainage lake”, a river’s flow of water, its sediment and its nutrients is unidirectional and because the water is flowing, the river is undergoing continuous physical change. The retention time of the water, sediment and nutrients at any point along the river during channel forming flow events is on the order of minutes, whereas a drainage lake’s retention time is much longer depending on its in flow and volume. A river’s stable channel plan form (e.g., meanders) and other dimensions (e.g., depth, width), and its floodplain, is dependent on the balance between the supply of water and sediment that is transported during flood events that typically occur every one to two years. Compared to drainage lakes, rivers have a high degree of plant, animal and habitat diversity. Modify its morphology by excavating a deeper and wider channel; flatten its slope, and increase the rate of sediment accumulation by constructing a dam and everything changes for the worse.
Supervisor Lipscomb stated that the dam “…re-establishes the historical water level in the area because it was built to replace a natural rock ledge.” There never was a natural drainage lake in Lincoln and Estabrook Parks. Deepening and widening of the 1.5-mile river reach altered or destroyed those features or buried them in accumulated sediment after constructing the dam and impoundment. Construction of the Estabrook Dam and impoundment did not replace the unique historic features of the Milwaukee River. It did not replace the former narrow and deep meandering river and floodplain wetlands. It did not replace historic fluvial processes that transport water and sediment, build floodplain and maintain historic and sustainable water depths. By all measures, the Estabrook Impoundment is longer by 1-mile, deeper by at least 0.4-feet, larger by 38-acres, and wider between 140-feet and 350-feet than the historic Milwaukee River.