STORM WATER CONVEYANCE
Large diameter storm sewer was installed to bring runoff to the pump station.
In addition to storm sewer installation, the 6th Street roadway was reconstructed.
Modifications were made to the intersection alignment at 6th Street and Western Avenue to improve safety.
Work on busy Burdick Expressway required closely coordinated traffic control.
Sections of watermain had to be relocated to accommodate roadway and storm sewer modifications.
PUMP STATION DEPTH
The wet well of the storm water pump station is more than 30 feet below grade. Sheet piling was installed to facilitate construction.
PUMP STATION EXCAVATION
Excavation was performed within the confines of the sheet piling and the concrete pump station substructure was then cast in place.
The exteriors of the pump station were selected to complement the neighboring Minot Public Library and City Hall.
The 975 horsepower triplex pump system can pump 40,000 gallons of storm water per minute.
OPEN TO TRAFFIC
Improvements of the completed project at the intersection of 6th Street and Western Avenue.
Overhead clearance was improved at the underpass by lowering the roadway. The increased clearance will accommodate passage of local fire trucks, improving response time.
Decorative railing and enhanced lighting create a pedestrian friendly sidewalk.
6th street UNDERPASS AND PUMP STATION project
Beginning in 2006, Ackerman-Estvold worked closely with the City of Minot to develop a project that would address recurrent flooding at the 6th Street Underpass, adjacent to the Minot Public Library and City Hall. Existing systems designed to convey the runoff from the approximately 160-acre urban watershed were grossly undersized. During the detailed analysis of existing conditions, it was also determined that adjacent storm sewer systems along 3rd Street Southeast (east of the project site) and Burdick Expressway (west of the project site) were undersized as well, contributing to the problem.
Ackerman-Estvold engineers designed a storm water management system that addressed all three concerns. By extending storm sewers into the uplands of the watershed, the developed areas contributing to the 3rd Street Southeast and Burdick Expressway storm sewers were effectively reduced, thereby reducing the peak flows within those systems and allowing the existing systems to operate as intended. Additionally, by capturing runoff within the uplands of the watershed, the system was designed to allow the upland runoff to be directly conveyed under pressure to the Mouse River, thereby eliminating the need to pump this runoff and significantly reducing the required size of the pump station. The reduced size pump station is a 975 horsepower triplex pump system with capacity to pump 40,000 gallons of storm water per minute.
Over the next handful of years following the initial analysis, the project remained idle due to both funding constraints and the historic 2011 Mouse River Flood. The project began to move forward again in 2012 with some re-evaluation of previous work and design of the project plans and specifications.
In addition to the extensive storm water upgrades, the 6th Street Underpass project included the reconstruction of approximately four blocks of concrete pavement, intersection alignment improvements, modifications to adjacent roadways including Burdick Expressway, water and sewer modifications, traffic signals, sidewalks, and lighting.
Our team was responsible for the design of this monumental project for the City of Minot and performed the construction engineering on the project in accordance with NDDOT practices. The $4.8 million roadway and storm sewer portions of the project were completed in 2014. The storm water pump station was completed in 2016 at a cost of $4.4 million. The construction of the project was completed in a closely coordinated effort between multiple independent contractors, the City of Minot, the NDDOT, Ackerman-Estvold and several residents and businesses in the project area.
Following our work on this project, our team remained interested in improving the area for the public. In 2016 Ackerman-Estvold volunteers stained and sealed the stamped concrete adjacent to the sidewalks as a part of a beautification project for the Magic Day of Giving.