Larimer-Weld Canal Crossing Structure (LWCCS)

The third of three regional improvement projects identified in the Master Plan of 2006, The Middle Basin Improvements, has gone through a metamorphosis. Originally identified in the Master Plan were two storm drainage channels used to convey local storm flows from the east side of I-25 back to Boxelder Creek and a siphon structure at the crossing of Boxelder Creek and the Larimer and Weld Canal (Canal) as an increased conveyance within Boxelder Creek between CR 54 and CR 52. The improvements were reduced in scope and refined in design. Most of this change of scope for improvements had to do with the eventual size and location of the East Side Detention Facility (ESDF), which greatly reduces the Boxelder 100-year flows where they cross the Larimer and Weld Canal. As a result, these improvements were reduced to a single side-flow spillway structure known as the Larimer-Weld Canal Crossing Structure (LWCCS) at the crossing of Boxelder Creek and the Canal. This structure allows the flood flows from Boxelder Creek to flow across the Canal and minimize the backwater in the Canal that historically spilled into the Cooper Slough Basin on the west side of I-25. The improvements insure that the south bank of the existing Larimer and Weld Canal will not fail when Boxelder Creek floods and overtops the canal.  This construction was completed in March 2016.