DFHADprototype071409.. - Urban Drainage and Flood Control District

DFHAD Prototype
720 S. Colorado Boulevard, Suite 410 S
Denver, Colorado 80246
phone (303) 757-3655
fax (303) 300-1635
PROGRESS MEETING FOR
HOFFMAN DRAINAGEWAY PLANNING & FHAD STUDY
MEETING MINUTES
Date: October 16, 2006
Location: Urban Drainage and Flood Control District Board Room
Distributions: Subwatershed Boundaries, Imperviousness Map, Soils Map, EPA SWMM
Routing, Preliminary FHAD Map
Attendees:
Name Organization Email
Ben Urbonas UDFCD burbonas@udfcd.org
Ken MacKenzie UDFCD kam@udfcd.org
Pete Brezall City of Thornton pete.brezall@cityofthornton.net
Besharah Najjar Adams County bnajjar@co.adams.co.us
Jessica Stevens Adams County Jstevens@co.adams.co.us
Rick Moser Moser & Associates moser@moser-eng.com
Teresa Patterson Moser & Associates patterson@moser-eng.com
David Delagarza Moser & Associates delagarza@moser-eng.com
I. Purpose
The purpose of the meeting was to present an update of the project progress. The meeting
included discussions about the expanded watershed boundary due to the flood flow splits,
land-use for these areas, and how the modeling should account for the additional
contributing flows. The preliminary 100-year floodplain delineation upstream of Rainbow
Avenue was also discussed.
IV.
delineation, a number of houses have been added around 88 th Avenue and Hoffman Way as
well as at the intersection with Rainbow Drive.
Alternatives
Teresa discussed the flooding issues along Hoffman Way and at Rainbow Avenue and
strategies to address capacity concerns. She also presented that the detention upstream of
Devonshire would need to be approximately 50 ac-ft to accommodate existing channel
capacities downstream of Devonshire Blvd.
V. Other Items
Ed Jennings, the engineer for the developer of the property south of HydroConduit property,
met with Teresa concerning changes to the topography on his client’s property. The
development of the lot changed the topography and will most likely affect the floodplain
delineation that we are doing. It was agreed that if updated mapping is supplied to Moser
within 1 month that the topography for the FHAD will be updated to reflect this change.
VI.
VII.
Schedule
An extension of the schedule was requested to offer more time to develop the FHAD and
the Alternatives. The draft FHAD and Alternatives Reports deadline has been moved to
December 1.
Upcoming Meetings
The next progress meeting has been scheduled for Tuesday, November 14th at 1:30 pm
at UDFCD.
The next public meeting will be held in late January to early February during the sponsor’s
Alternatives Report review period to take the public’s comments into consideration for the
Selected Plan. Pete will check on available dates at the Thornton City Hall.
II.
Expanded Watershed Hydrology
Teresa presented the additional subbasins that were modeled to define the split flow
conditions from Hoffman Drainageway. Ben stated that the flow spilt at the railroad should
be modeled in a manner that the floodplain west of the railroad will account for the split flow
and the floodplain east of the railroad will assume that all of the water overtops the railroad
instead of splitting.
The future land use of the area between Devonshire and the railroad was questioned. The
distributed exhibit shows 80% impervious. Jessica is going to check with the County’s
planning department to see what it’s future plans were and inquire if the trailer home area
south of 86 th Avenue will remain zoned as designated.
III.
FHAD
David presented the preliminary flood hazard area delineation results for the area above
Rainbow Drive. While some houses appear to have been removed from the FIRM
Hoffman Drainageway Planning & FHAD
Progress Meeting Minutes 10/16/06
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Hoffman Drainageway Planning & FHAD
Progress Meeting Minutes 10/16/06
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