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Rushford City Council receives levee recertification update


Fri, Jun 12th, 2009
Posted in Government

In a lengthy, occasionally vague presentation, the council heard an initial report by URS Corporation and American Engineering Testing at the Monday, June 8th meeting. The presentation detailed the current analysis of the flood protection system, as well as statistics of Rushford's flood history. The recertification, which is being funded by a grant from the Minnesota DNR, is, as City Administrator Windy Block called it, "An uphill battle."

The intention of the study is to provide documentation to FEMA that the levee system meets current flood protection standards. If this cannot be done prior to August 25th, 2011, the areas behind the levee would be classified as a floodplain.

Preliminary findings indicate that while the system isn't failing, "seepage and uplift at the land side toe generally do not meet FEMA standards." Basically, it does not cover the margin of safety that FEMA now requires. As engineers explained, water against and under the levy create uplift pressure. In highly permeable soils, such as sand, this water creates under-seepage. The makeup of soils behind the levy must have enough weight, or resisting force, to compensate for this uplift pressure. This can become a "hazard to the levee" when the water carries additional soil, forcing greater velocity against the land side soil "blanket." This can lead to a "blowout" or breech of the levee system. While the 2007 flood didn't cause such a breech, there was upward seepage.

In obvious frustration, Mayor Les Ladewig asked, "How can we be expected to fulfill these standards when we met the standards when the levee system was built?"

Engineer Art Kalmes stated the facts bluntly, "We're playing by their rules," noting that FEMA can and has imposed new standards since the levee's construction in 1967.

Continuing on, Ladewig made his feeling clear, "What it represents for this community with these new specifications... it could impose very expensive financial ramifications."

The group laid out a plan of corrective measures needed to improve seepage conditions and to meet FEMA standards. The solution is a trenching system on the land side of the levee, roughly 5-10 feet wide and similar in magnitude for depth, to alleviate some of the uplift pressure. The seepage would have a ponding effect in the trenching areas.

In response to a question of what assurances the Corps of Engineers can give the city, the team assured the council that it had discussed initial analysis and the Corps had concurred that the trenching system would be a reasonable action. Clarifying the solution, the team said, "Seepage is currently finding its own path. Here, we'll tell it where to come up." They further stressed that the goal is to preserve the overall integrity of the levee and that more information is needed.

As the discussion progressed, Public Works Director, Jeff Copley, asked on numerous times, "If you need to build this filter space (trenching), will it affect any houses?"

The question was met with silence on all occasions followed by uneasy responses from team engineers, "We haven't gotten that far down the road yet." "From an aerial point of view, it would seem relatively unintrusive."

There was also a question of where water from the trenching areas would run. While the team replied that the water would be directed into storm sewers, it only prompted more questions. Mayor Ladewig asked with a nervous chuckle, "If the storm sewer fills, where will water from the seepage trenches go?"

The discussion continued, but the overall mood was summarized best by Ladewig who stated, "I think this gives you a good flavor of what we feel. Keep working on it, but we're not going to swallow it tastefully."

While the evaluation will continue, there are two glaring problems. The team pointed out:

First, a roughly 800 foot section of Highway 43 doesn't meet FEMA freeboard requirements. Freeboard is defined as a factor of safety, usually expressed in feet, above a flood level for purposes of floodplain management requirements. This section of roadway is too low and the city will need to work with MNDOT to remedy the problem.

Secondly, the ditch along Highway 16, towards Lanesboro, poses an issue. Nicknamed by the team, the "Ditch to Nowhere," the area, per the original plan, requires sandbagging across the roadway to prevent water from running back into Rushford.

DNR Trail Trestle Bridge

With much anticipation, those present heard that the trestle bridge "did not cause flooding" during the 2007 flood. Per study findings, the water would have overtopped the levee without the bridge in its path. This prompted serious disagreement between scientific findings and those who saw the flood's effects personally. The team reiterated that after computations, the bridge would not "unduly affect flood levels during a 100 year flood." There was some "impact, but not enough to report to the Corps or FEMA."

With several in the room declaring they didn't "care what the findings show," the team further pointed out that the goal wasn't to do an extensive study, but to satisfy the levee standards." They did, however, acknowledge that there are "limitations of computations."

Wrapping up

As part of the presentation conclusion, the team highlighted the next steps for the city, as well as concerns if flood protection system certification is not met. The team plans to continue the evaluation and design of a seepage control system and pursue funding for corrective measures. The concerns of non-certification range from possible wastewater treatment plant flood-proofing, or relocation needs, to a potential hindrance of repair or improvements to other existing structures. Another major concern is flood insurance rates. Current rates are reasonable because Rushford is not currently mapped in a floodplain. If the areas behind the levee are mapped in a floodplain in the coming years, rates would increase substantially. Residents are encouraged to purchase flood insurance as the rates would be grandfathered in if maps change.

Assessment Policy

A significantly shorter segment of the meeting was focused on the ongoing process of developing an assessment policy for utility improvements for the city. City Administrator Block described that what "drives most people's questioning and thinking is the percentages." The developing policy, which was used to generate previous open forum projections and estimates, is being met with some resistance, but also certain acknowledgment of what needs to happen.

Block said there was negativity from some citizens, "just as there had been at the other hearing." He continued, "Nobody wants to pay. They don't cherish the idea, but there is acceptance of a responsibility and a recognition of what happens when you don't do anything."

City Vision

The city was presented with an offer to purchase approximately .55 acres in Lot 7 of the Rush Creek Business Park by brothers Brad and Glenn Woxland, operators of G.S. Woxland Plumbing. Apparently, as a "result of a possible offer to purchase and other long-term community visions, the Woxland's have decided not to build their proposed warehouse on a 1?2 acre site that they own along Industrial Drive (downtown Rushford)." Council member Jim Wolter said bluntly that the purchase "is a good thing they're offering to do," noting that there are "better uses for the area by the depot."

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