Granby and sable ditch major drainageway plan (MDP)
Located in rapidly developing Aurora, Colorado, the 2700-acre Sable and Granby Ditch Watershed has not been independently studied since the 1990s. Spanning from the downstream end of Buckley Air Force Base to roughly I-225 and E 30th Avenue, this watershed is home to several Aurora Public Schools, the new Citadel Development, several houses of worship, community facilities, commercial and retail facilities, and Aurora residences, as well as housing redevelopment opportunities at several vacant or underutilized parcels.
Focusing on updating the watershed and floodplain, the Granby and Sable Ditch MDP Project will include coordination with sponsors Urban Drainage and Flood Control District and the City of Aurora, as well as stakeholders from Aurora's business owners and citizenry. To hear more about this project as we move forward, please check out the "Meetings" tab below, which will be updated regularly with new information and upcoming meetings.
To mitigate current flooding and prevent future flooding, this study and master plan will provide updated baseline hydrology, a CLOMR/LOMR, hydrographs for watershed and subwatershed, HECRAS and CUHP modeling, alternatives analysis for flood mitigating Capital Improvement Projects (CIPs), hydraulic analysis, conceptual design, and integration into the City’s Digital Stormwater Master Plan.
Define the 100-year floodplain
Update Aurora's floodplain layer and prioritization tool for stomwater planning in Aurora
Update the floodplain for the watershed
Identify and analyze outfalls for Aurora Parks
Update hydrology for the watershed
Update Aurora's Digital Stormwater Master Plan
Identify ways to mitigate flooding in the area
Identify Capital Improvement Projects in the watershed
Provide conceptual design for the preferred alternative for mitigating flood in the area
Databases currently show Granby Ditch ending at Colfax, and this study will extend the boundary
Aurora Public Schools and Buckley Air Force Base may have private or P3 developments that impact the imperviousness in the watershed
Updating the watershed will impact Aurora's CIP list
Current flooding shown upstream of the current "end point" of the watershed (at Colfax)
Updating existing and future conditions in stormwater modeling will impact future stormwater planning to plan for development and densification in the area
Inlets at Colfax are undersized, which results in overtopping of Colfax
Flooding has occured at Hinkley High School, although no structures were impacted
High Line Canal and various ponds are located within the watershed and should be analyzed for flood impacts
Next public meeting
Subject: Granby/Sable Public Meeting
When: October 23, 2019
Time: 6:30 PM - 7:30 PM
Where: Aurora Municipal Center, 15151 East Alameda Parkway, Aurora, CO 80012 - The Aurora Room (Conference Room)
Subject: Granby/ Sable Public Meeting
When: Wednesday, October 23, 2019 6:30 PM-7:30 PM (UTC-07:00) Mountain Time (US & Canada).
Where: Aurora Municipal Center – Aurora Room; 15151 East Alameda Parkway, Aurora, CO 80012
The Draft Granby Sable MDP Alternatives Analysis, dated November 2019, can be downloaded by clicking the following link:
Additional Info & Useful Links
City of Aurora Digital Stormwater Master Plan