DAM – CITY COUNCIL MEETING PRESENTATION 9-18-2007
Mr. Mayor and members of the Council --
WHERE WE ARE TODAY:
A small problem ignored over weeks if not months this past winter and spring has now turned into the big gap in the riverbank. Some are using this situation in order to transform the pond into their version of an ideal river by destroying the pond wetland environment.
The DNR has allowed the city to stabilize the riverbank itself from further erosion but they have also told the city not to stabilize the dam while this issue plays out. There is a potential that this could cause the dam to get undermined and severely damaged. That this dam also happens to be City taxpayer owned property seems to be irrelevant.
The State Dam Safety Engineer in a letter to me wrote: “The City of Windom owns the dam and will ultimately decide its future.” In an e-mail to me the same Department also stated “All decisions are ultimately in the hands of the City Council.” Do they mean this or don’t they?
The State is willing to fund repairs at other dams as a review of past and proposed dam safety budgets show. However it appears they intend to prevent funding of dam repairs for the Windom dam, because instead their action is to already ask for $150,000 in fiscal year 2008 for the specific purpose of dam removal due to alleged safety concerns, according to their budget request listed on a state website.
This is despite a claim in published documentation provided to the City that “The agency’s goal is to reach a consensus on which action – repair or removal – is the most appropriate not only for the river ecosystem, but also for the surrounding community. The Minnesota DNR feels it is important to have local buy-in and support before removing a structure from the river.”
(Source: “Dam Removal Success Stories – Removal of the Welch Dam in Minnesota”
As a consequence of allowing the river bank to be compromised, a large wetlands environment has been damaged where geese, ducks, pelicans, seagulls, herons, egrets, eagles, songbirds and muskrats as well as turtles and fish once flourished as many of us can personally attest to. We have pictures of families of geese with their young that used to come and graze in our backyard come Mother’s day every year. Until this year. We even have a picture from our living room window of an eagle feeding on carp. Now this same area is infested with weeds. Now dead clams and dead snapping turtles on a dried up river bottom are the consequence.
This wetlands destruction has all been done without apology to the adjoining residents for doing so, or involving river residents and landowners in any ongoing process of developing options to resolve the current situation. If a private party had done this scale of damage to state owned land I have every reason to believe they would have been prosecuted.
The damage to the view of the river is very real and tangible, including for those of us along the river who had planned for these to be the last homes we will ever buy. However, even all this is a side issue for reasons I will explain.
THE UNINTENDED CONSEQUENCES OF A DAM REMOVAL IN WINDOM:
The stated goal by some is to place about 7 riprap riffles in a re-graded meandering stream channel so that sturgeon, mussels and canoeists could benefit. To support this and related work, landowners would be expected to donate land in some form. Given the harm that has already been done, we do not expect permission will be gladly given to do what many may perceive as further damage to the situation. We note 4-wheelers have already been seen and heard in the dry river bed at nite at least once so far this summer. Will more be coming?
Another unintended potential consequence of permanent dam removal in Windom is the potential of slope instabilities in the Rolling Green neighborhood. Without the dam, the groundwater table in Rolling Green will permanently be undergoing greater fluctuations in the hillside and river basin than it ever has with a dam in place. This action has the potential to cause slumping, cracking and sliding of portions of the Rolling Green hillside and river banks over time as it has in other situations with sloping ground. Historically, a dam was here first, then the Rolling Green neighborhood was developed. This risk needs to be assessed by qualified professionals and any additional long-term risks need to be disclosed to the affected residents.
The potential for erosion of the in-place sediment, with subsequent downcutting and erosion of the riverbank slopes will also be a distinct potential consequence of removing the dam and restoring a meandering river. The Des Moines River absolutely is a meandering river if it is not controlled. Either gradually over years or during a major flood the increased risk is there.
It is not just me as a licensed engineer saying these potentially serious concerns have to be considered and addressed. It is also the opinion of a major outside engineering firm I reviewed this situation with that has significant experience in these matters. A letter from Barr Engineering Company in Minneapolis to me states in part the following:
“Making a decision without adequate information may result in surprises or unforeseen conditions that could increase project costs or result in outcomes that are different than were expected. Engineering issues that should be addressed in assessing alternatives for the Des Moines River include the following:
- Public safety, including minimizing or eliminating spillway hydraulics that cause a “drowning machine” effect
- Impact on utilities and infrastructure, including scour or erosion at utility crossings, bridge piers, and bridge abutments, as well as impact on water supply from river sources
- Impact on adjacent structures and embankments, including bank, embankment, and foundation instability that may be caused by changes in surface water and groundwater levels, and could affect buildings, roads, or utilities in proximity to the river
- Impact on flood levels and flood damage, including inundation from flood waters or erosion from flood flows
- Impact on river channel, and understanding of local and regional river mechanics, including expected erosion, stream meander, bank stability, shoreline vegetation, and how these might impact the landscape and infrastructure near the current river alignment
- Impact on recreational opportunities, including fishing, canoeing, snowmobiling, biking and hiking
- Impact on aesthetics, including views of the river water surface and shorelines from public and private vantage points”
Also, I note the following article from North Dakota State University regarding the benefits of low head dams such as ours:
“We suspect that the dams are affecting the rates of slope instability in two ways:
1) in the pool area, a constant water level serves to induce continuous hydraulic pressure against the channel walls, slowing clay flow toward the channel, and
2) the velocity profile of the river is "evened-out" across the channel because of the presence of the dam. Because water spills over the lip of the dam at a uniform rate, erosion is no longer concentrated at the cutbank positions of meanders within the pool region.”
EXHIBIT -- FARGO DAM PHOTO
“Upstream of this dam near 12th Avenue North, the rates of slope instability are markedly reduced. Dams can be effective engineering structures to remediate problems with mass wasting along the Red River.
As one example of the slope stability risk in Windom, the Riverview apartment building has about 10 feet of flat ground between it and the riverbank – not a big safety margin during a major flood event if a meandering and flooding free flowing river starts undercutting the river bank. The state proposed the installation of slope protection using “soft” measures such as willow shoots and native grasses along the river.
The potential of scour erosion at the Highway 62 Bridge has also not been evaluated before embarking on the agenda of dam removal. This risk is being reviewed within MnDOT. The point is that no one to my knowledge assessed this risk before refusing to allow the City to at least stabilize the existing dam.
Another unintended consequence of dam removal that was mentioned is that the weeds will freeze, die, and dry up. How well will the Fire Department be able to fight a grass fire down on the river bed on a dry windy fall or early spring day without a dam? A fire might burn off stabilizing vegetation on riverbanks. Who will then stabilize the bare riverbanks if there is a spring flood? Again, a pond would do much to reduce this risk.
None of these potential unintended consequences has been recognized prior to the push for dam removal on behalf of mussels, sturgeon and canoeists, which have all been cited on multiple occasions as reasons to remove the dam. Where do the citizen’s and landowners risks, concerns and wishes fit in? Much as some may prefer to, they cannot always put all the toothpaste back in the tube and pretend mankind, or the dam, was never here. This river must be considered in the larger context of its surroundings, not just in the narrow terms of the river itself.
THE POTENTIAL OF WHERE WE COULD GO INSTEAD, IN 2 PHASES:
If the city allows the dam to be destroyed, it will be gone forever. It could be such a great resource (again) for the city and help reconnect people with the natural world and the river environment.
PHASE 1, THE DAM, NOW: key stakeholders with the most at risk as previously described should have major input in this dam/no dam decision. Having been informed of the risks, consequences, costs and benefits, the overwhelming consensus appears to be to keep the dam.
The state has expressed concerns about dam safety. This dam does have a potential to cause drowning in major flow events. We understand there has been one drowning downstream of the dam itself. Concerns have also been expressed about fish traversing the dam, and canoeists having to pass around the dam.
The DNR has performed “low head dam retrofits” in the Red River Valley. They leave the dam as is but add large rip rap boulder slopes, with a 5% grade, to the downstream side of the dam. Water is directed towards the center of the channel to create a flume effect with small pools for fish.
A 1999 “Fish and Wildlife Today” article states the following about a Fargo ND dam rehab:
“Ingenious engineering is helping fish populations and saving human lives on the Red River.
Luther Aadland, a research scientist with the DNR Ecological Resources Section at Fergus Falls, recently designed a modification of the Fargo Midtown Dam to eliminate the powerful flow of water that once plunged over the structure. That rushing water created a deadly hydraulic swirl below the low-head dam, Aadland explains. It had trapped and drowned at least 19 people since it was built in 1960.
The fast water also impeded fish migration. The Fargo Midtown Dam is one of eight dams on the main stem of the Red River blocking fish from reaching spawning tributaries farther upstream.
Rather than remove the 10-foot-tall concrete barrier, the DNR hired contractors to place rock fill and boulders below the dam for roughly 170 feet down river. This eliminated the dangerous waterfall and created riffles and eddies through which fish can swim upstream. The center of the river is now a rapids passable by canoeists and kayakers.
Assisting with funding were the cities of Fargo and Moorhead as well as eight agencies besides the DNR.“
To better illustrate this concept we have a video to show how this works:
PLAY DAM RETROFIT VIDEO CLIP EXCERPT
The State might well be expected to reimburse some project costs up to $150,000, what they are now intending to pay to destroy the dam as per their Fiscal Year 2008 budget request to the legislature. The City may be expected to pay part of the costs for the riprap type retrofit on the downstream face for safety, fish, and the occasional kayak. It appears this will also vastly improve the aesthetics of this area, and revitalize Island Park for the benefit of all Windom citizens. It will also build needed support for a potential larger, follow on project upstream of the dam.
River stakeholders and city residents would have no guarantee of any follow up work under Phase 1, the situation would only be restored to the former status quo of a nice wetlands environment that was a bona fide resource enjoyed by a tremendous variety of wildlife. The people along the river did not think this was half bad, we thought it was downright reasonable. In addition, the downstream risks are eliminated under Phase 1 to address safety and fish passage concerns.
This eliminates the crisis aspect of this situation. It also eliminates the long-term potential geotechnical risks to homeowners imposed by a dam removal, and gives time for all parties to fully consider and develop Phase 2.
We also note that the dam and pond is a public asset that has been under-appreciated. Neglecting the dam, not budgeting for inspections, maintenance or performing timely repairs is not the dam’s fault. We need to raise the level of expectations so all of our city assets are better constructed, better maintained, and preserved for future generations. The DNR has stated maintenance costs are a dam problem that warrants their removal but this is contradicted by their own “2006 Capital Budget” request, which states in part the following regarding buildings and facilities under their control…
“Deferred maintenance results when the upkeep of buildings is postponed due to funding shortfalls. Problems are compounded when minor repair work develops into more serious conditions.”
“In the long run, deferred maintenance can lead to…shortened building life and the erosion of asset value.”
“Maintaining facilities in optimum condition enhances user satisfaction…reduces operating costs, and safeguards the state’s long-term investment in buildings.”
“Projects completed now will mitigate more costly repairs in the future.”
Yes, the dam will take taxpayer money, as does every other capitol investment from streets and bridges to telecom projects and fish hatcheries. The City does have the means to make this happen if it chooses to. Preserving the dam environment is justifiable, warranted, and desired by stakeholders who just also happen to be Windom residents.
PHASE 2, THE RESERVOIR:
A concern of Windom citizens that needs to be considered is – why spend money on something some may not easily appreciate? The pond could be a bona-fide fishing, canoeing, scenic and tranquil setting yet again for everyone, for decades to come, as it has been in the past. The City history is rich with residents enjoying the pond environment in a diversity of ways. The City does not have that many scenic areas to spare. If the public uses it, then they will also have incentive to provide stewardship of the resource.
Sedimentation is a concern often raised when objecting to the notion of a Des Moines River pond environment. The state has calculated sediment-loading data that implied the sedimentation rate is increasing dramatically; therefore it is not practical to keep a dam in place. Two points to consider:
1) The samples are in the form of “Total Suspended Solids”. A United States Geological Survey research paper notes that this method, which was originally designed for analysis of wastewater samples, “…is shown to be fundamentally unreliable for the analysis of natural water samples.” These numbers include everything from actual sediment to non-sediment items such as algae and fertilizer.
2) Practices such as farm drain tiling in fact reduce sediment runoff and therefore are helpful to the situation. The local county environmental office is also working to improve the situation by for example promoting best management practices in farming. A contact at the Cottonwood County Environmental Office noted the sediment-loading situation is improving, not getting progressively worse.
The river basin needs to be properly surveyed to get reliable information in regard to the in place sediment. Before consideration can be done in any detail with the sediment issue itself, the problem needs to be defined in terms of what is actually there.
One idea we discussed as an example is to leave a long island in the river, with pedestrian bridging at each end to establish a seasonal “Riverwalk” nature and walking trail for summer use. This approach may also benefit in part from grant funds used for bike paths, nature trails, and the like.
For Phase 2 our group suggests the City commission an engineering study using water resource professionals and make use of consensus building techniques to perhaps develop a “Windom Riverwalk – Connecting our Community” concept which will likely involve dredging as other cities have done, with reshaping and revitalizing of the river area. This would create ownership and stewardship of the river by Windom residents reconnecting with the river. We expect this may well require City funds in part, as well as funds from other sources. An island “nature walk” would be unique and likely found nowhere else in the state.
For all these reasons we will continue to build public awareness of these issues and we ask for the City to support these efforts, which include proceeding now with Phase 1 of this project.
We thank you for your time and consideration, and will try and answer any questions you may have.