Olsson was retained by Mile High Flood District (MHFD) and the City and County of Denver to provide design of storm drain system improvements in the Marston Lake North Drainageway. The main objectives of the project are to separate stormwater flows from the Bowles Lateral, improve drainage and alleviate high ground water near the properties adjacent to the Bowles Lateral at Saratoga Place, and improve the overall drainage and reduce street flow through the project area.
The general design concept is to install new storm drain infrastructure to collect and convey 100-year flows from West Wagon Trail and South Field Way to the existing storm drain system downstream of the Glenbrook Pond. Storm flows will be separated from the Bowles Lateral with the improvements. The project will be completed in two phases.
Phase I consists of constructing improvements from the Glenbrook Pond outfall to upstream of the Bowles Lateral. Phase I includes installing 42- and 48-inch storm drain trunk line with laterals and inlets in West Garrison Street and South Garland Street, then crossing the Bowles Lateral to West Saratoga Place. As a part of the Phase I improvements, sanitary sewer and water lines will be adjusted as well as the Bowles Lateral. In South Garland Street, the sanitary sewer main will be lowered and water line will be relocated to accommodate the new storm drain. The Bowles Lateral will be piped via 60-inch pipe, upstream of the existing 72-inch culvert under West Saratoga Place. A headwall and wingwalls will be constructed at the culvert entrance. An 8-inch French drain will be installed along the new Bowles Lateral pipe in the vicinity of the ditch to collect groundwater. Curb Ramps will be replaced the intersections of South Garrison Street and South Holland Way, South Garland Street and West Garrison Street, and West Saratoga Place and where Wagon Creek Trail crosses West Saratoga Place. On West Garland Street, curb, gutter, and sidewalk will be replaced.
Construction for Phase I is planned to begin the second quarter of 2022 and will last approximately 6 months.
Phase II includes installing improvements upstream of the Bowles Lateral, and at Hoyt Street and West Saratoga Place. Phase II includes installing 36- and 42-inch storm drain trunk line with laterals and inlets along West Saratoga Place, West Wagon Trail Drive, and South Field Way. The existing storm drain system in South Field Way will be connected to the new system at the intersection of South Field Way and West Wagon Trail Drive. Construction will also include curb ramps, curb, gutter, and sidewalk replacement. Additionally, inlets, laterals, and storm drain trunk line will be installed, conveying storm flows to the existing system in Hoyt Street, ultimately conveying flows to the Glenbrook Pond.
Construction for Phase II is planned to begin in 2023, pending funding, and will last approximately 5 months.
Bowles Ditch Project Map