A $12.6 million project that would alleviate flooding near Dakota Square Mall could move to the top of the City of Minot's storm sewer construction list.
City engineer Lance Meyer presented a work schedule to the Minot City Council's storm sewer ad hoc committee Monday that recommended constructing the 16th Street Southwest project in 2016. Design and planning would take place next year.
The proposed storm sewer priority list goes to the city council for approval without a recommendation from the committee, which lacked a quorum.
Last year, rain water flowing through Puppy Dog Coulee flooded a community park in the southwest Minot development of Green Acres, shown June 5, 2013. The City of Minot is considering a project to improve the storm sewer system in the area.
The Puppy Dog storm sewer improvements would be a boon for residents in Green Acres who have experienced flash flooding from heavy rain or snowmelt in recent years.
"That would be wonderful," Green Acres resident Jacque Rutten said after learning of the potential project. Rutten's home is one of two houses that have gotten the worst of the flooding.
Since she moved to Green Acres in 1976, Rutten said, water has come into her yard on occasion, but in 2010 for the first time, runoff flooded her house. In 2013, the house flooded in April and June.
"This year it came pretty close," she said of the water.
Puppy Dog Coulee drains hundreds of acres before gushing into Minot, passing through the housing development located just west of Dakota Square Mall. It's been particularly problematic for the homeowners in lower lying areas.
Homeowners have met in the past with the Ward County Water Resource Board about upstream water retention and have asked the city to enlarge or add to the culverts under 16th Street, which flooded in April 2013 due to ice blocking the culverts.
Meyer said the existing storm sewer was designed for a 100-year flood event. Improved technology for assessing the land contours and hydrology since has redefined that 100-year event. Based on the new modeling, the city has determined that its existing storm sewer isn't at an adequate capacity.
The engineering department's proposal is to install larger culverts and replace pipeline through the Dakota Square Mall area. In addition to the need to enlarge the system, the city has discovered that pipeline has been deteriorating and requires replacement.
"It's significant," Meyer said of the project. "It will be the largest one that we have ever done. ... A project of this size and magnitude doesn't come cheap."
The $12.6 million cost would be split between the city's storm sewer development fund, which all water users pay into, and special assessments on property owners in the large drainage area within the city. The estimated area extends from the southwest edge of the city nearly to Broadway on the east. It has portions extending south of 37th Avenue Southwest on the west side of 16th Street and north of the U.S. 2 & 52 Bypass on the east side of 16th Street.
The area around the mall where excavation will need to take place also presents challenges.
"It's going to be a difficult one to build, but one that's becoming more and more necessary every day," Meyer said.
Rutten said it also will be important to slow the water running into the city from the large rural drainage area. The water resource board has looked at a retention project but reported last year that it lacked the funds to construct any project.
Upstream retention in the rural area is being considered as the city drafts a stormwater master plan, Meyer said. There are a couple of options that look feasible, he said.
"However, based on the modeling, as the city continues to develop in the southwest, most of the water that's going to flow into the culverts is going to be from the developed portion of the city," he said.
The Puppy Dog storm sewer was not on the city's 10-year capital improvements plan previously. Meyer said the deteriorating condition of the pipe is making the project a greater priority.
The Puppy Dog bumped down to second place a $1.7 million storm sewer project along 18th Avenue Southwest, which includes drainage from the Edison Elementary School neighborhoods.
The schedule for future years, by priority ranking, includes:
- a $3.3 million project to improve drainage in the area of 10th Street and 31st Avenue Southwest.
- a $2.4 million project at 16th Street Southwest and Southwest Knolls, which would also address flooding of the 16th Street and Burdick Expressway intersection and underpass.
- a $468,000 project in the Polaris Park watershed, which would address flooding at North Broadway caused by an under-sized culvert.
- a $2.28 million project on 11th Avenue Southwest near Scandinavian Heritage Park.
- a $316,374 project at Main Street and 37th Avenue Southeast.
- a $1.14 million project at Fourth Avenue Northwest and Eighth Street near Riverside Park.
- a $183,831 project affecting 38th Street Southeast and Keyes Addition.