Rosemount’s wide-open farms, fields and natural ponds serve as a stormwater overflow system for floodwaters. As its population grows, the city questions whether there is a need for an underground overflow system.
Rosemount is asking the Vermillion River Watershed Joint Powers Organization to evaluate an idea to build pipelines moving water south through Empire Township into the Vermillion River, “because cost implementation would now be through multiple communities, not just through Rosemount,” said Andrew Brotzler, Rosemount’s director of public works and city engineer. “And then, would it be feasible with the restrictions that are in place on the Vermilion River given its trout stream designation?” The city’s previous plan was to have water flow east into the Mississippi River.
Why go south?
Since most of the city’s population lies to the west, going to the Mississippi on the city’s eastern border would involve building 9 miles of pipeline. “We would be piping water away from an area in which [stormwater] naturally flows south,” Rosemount Mayor Bill Droste said. The city also questions whether it can build pipelines through undeveloped land, Brotzler said. The Mississippi plan would cost $25 million to $30 million, Droste said. “In many ways, it would be very cost-prohibitive,” he said. “I don’t think that it’s the best plan.”
Type of flooding
The most likely cause of flood is snow melting in the spring, “where a lot of snow on the ground froze and it has to be retained in catch basins. If the catch basins are full, we don’t have a piping structure and lift station structure all the way to the Mississippi River,” Droste said. One advantage the city has: It sits on sandy soil, allowing for water to percolate into the ground.
About one-third of Rosemount’s land is developed, and its population has grown by more than 50 percent since 2000. “Long range, what we would need to do is build some lift stations and install some pipes in case we have a hundred-year flood,” Droste said.
Liala Helal • 952-746-3286