Arlington-Pascal
Stormwater Improvements
a subwatershed (Como-7) approach to a capital improvement project involving flood prevention and water quality improvement
The overall project goal was to meet the Como Lake Strategic Management Plans (CLSMP) objective of improving water quality by reducing phosphorus inputs to Como Lake while at the same time eliminating residential flooding problems. In designing a solution, EOR completed a detailed study of the watershed’s sub-watersheds through a series of sophisticated engineering models that included both an extensive hydrologic and hydraulic evaluation and modeling of existing and proposed conditions using XP-SWMM, as well as the use of P8 in the modeling of water quality.
Accomplished goals through a 4 yr. implementation plan that included:
- 8 Rain Gardens - to address volume control and water quality.
- 8 Infiltration Trenches - to address stormwater rate and volume control.
Totaling 3220 feet in length, at 15 feet wide x 5.5 feet deep these represent the first time that such a design was constructed directly under the roadbed rather than on the side of the road. - A Large Underground Infiltration/Storage Facility - to address flooding volume control and improve water quality. At 651,600 gallons, this facility represented the largest constructed in Minnesota at the time.
- A Regional Stormwater Pond/Infiltration Basin - to address stormwater rate and volume control. Located in the Como Park Golf Course, this pond incorporated a 30” diversion pipe to eliminate unnecessary costs that would have been incurred with the initially proposed 60” pipe expansion project. This change represented a savings to the City of St. Paul of approximately $1.5 million.
- Municipal Stormdrain Improvements - to address stormwater rate and volume control. Stormsewer size was optimized and the number of catch basins was increased at key locations as part of the City of St. Paul's street reconstruction project.
Upon completion of this project:
Water quality improved through the reduction of stormwater volumes and phosphorus into Como Lake, community flooding events were reduced through increased infiltration capacities, and the creative cost-saving measures implemented by EOR reduced the overall budget by 2.5 million dollars for this Capital Improvement Project.
This series of projects has received the 2010 Environmental Initiative Award for
Natural Resource Protection & Restoration, 2010 ACEC-MN Grand Award for Water Resources Engineering, 2008 MAWD Project of the Year Award, & the 2007 Sustainable St. Paul Award. These awards have increased public exposure to EOR’s stormwater management solutions & the benefits they bring to local communities.