Study: DL Water Not Big Threat
Water from Devils Lake does not pose a big threat for catastrophic flooding in Valley City. The public learned this during a public forum Thursday sponsored by the U.S. Army Corps of Engineers, St. Paul, Minn. District, and the City of Valley City, where they informed audience the results of the first phase of their feasibility study. The study also showed that some of the alternatives for flood risk management considered were not found to be cost effective and would not be justified for implementation as a federal project.
The forum, held at the Hi-Liner Activity Center, was the second one held that addresses the estimated $1.5 million Valley City Sheyenne River Flood Risk Management Feasibility study, funded jointly by the Crops and Valley City in partnership with the State Water Commission, that evaluates alternatives for flood risk management in the area. The last public forum was held in July.
“We recognize that the risks associated with Devils Lake overtopping could have high consequences, but that there’s a low probability of that event occuring,” Sierra Schroeder, project planner, said during the presentation. “The risk in the short term of the lake reaching that elevation is higher; in the long term that risk is substantially decreasing. This is again because of the state-operated pump outlets that are expected to be successful and effective at reducing the lake levels.”
During July’s public forum, the Corps told audience that they were not ruling out any alternatives and retention proposals, but on Thursday, Schroeder, said they found many of those alternatives to be inefficient cost-wise.
Corps officials said that after analyzing data they found that the cost-to-benefit ratio does not meet the federal government’s guidelines for the Corps to become heavily-involved in building flood control structures.
Schroeder told the audience that cost effective alternatives will be carried forward and further developed in the next phase of the study.
The array of alternatives found included no action or continuing emergency flood fight measures, non structural measures such as raising buildings or relocation, structural measures such as levees and floodwalls, and modifications to the operations at Baldhill Dam and Lake Ashtabula.
The Corps has suggested increasing the pool drawdown at Lake Ashtabula by two feet.
“This alternative entails monitoring snowpack during winter and under certain conditions when it looks to be high levels of snowpack and we anticipate large scale of spring runoff and spring flooding to draw the resivor down below the currently authorized elevation,” Schroeder said, adding that an environmental assessment would be required to carry out this alternative, which the Corps is currently working on.
The Corps also suggested modifications to Baldhill Dam to accommodate wind wave action, which Schroeder said could be combined with increasing the pool down at Lake Ashtabula.
“At this time, this alternative has been analyzed in a rough level of detail and would have to be refined and optimized as we continue the next phase of the study,” Schroeder said.
The study was broken into three phases, and the first phase of the study has been completed. Tasks completed in this first phase include initial data collection, updating the hydrologic and hydraulic models, economic analysis of average flood damages and the development, evaluation and screening of the full array of flood risk management alternatives.
The next two phases of the study are scheduled to be carried out in 2013 and 2014. Phase 2 will focus on identifying the tentatively selected plan and Phase 3 will include development of the tentatively selected plan.
City officials and area residents in attendance gave their concerns during an hour-long question and answer period following the slide show presentation.
The Corps’ study found that Devils Lake water is not a big threat to the city, and that with the new pumps, there is only a 4 percent chance of Devils Lake water causing a catastrophic flood along the Sheyenne River and in Valley City.
But some residents disagree.
City Commissioner Madeline Luke acknowledged that while the study’s results came from data analyzed over the past 50 years, it cannot look into the future.
“I think that climate change, drainage, outlets, these are all things that are new and have not been in the historical record, so we’re looking at a new world here,” she said. “And I know science is a good way to start, but there’s just so much uncertainty.”
City Commissioner Matt Pedersen said that the study does not look at the economical impact on a local level.
“It’s important to note that their analysis doesn’t take into consideration local impacts in terms of, if we lost the university due to flooding, or we had major flooding downtown and lost our downtown business district, so it doesn’t take into account the economic impacts of those kinds of events,” he said.
“We’ve so far been very successful, thanks to friends at the State Water Commission to partner with us and get us in a very good stop to start to get some money over the next three bienniums,”Pedersen added. “So we’re going to move forward.”
City Commissioner Mary Lee Nielson and other city officials have requested $11.6 million for the next biennium in state funds that would be used in flood protection and property buyouts. The amount is in the governor’s budget but has yet to be approved by legislature.