2017-081 PEC-4 Downtown Floodplain ReclamationDate: November 3, 2017 Report No. 2017-081
INFORMAL STAFF REPORT
TO MAYOR AND CITY COUNCIL
SUBJECT:
PEC-4 Phases 1-4: Downtown Floodplain Reclamation
EXECUTIVE SUMMARY:
The PEC-4 Drainage Improvements project consists of the design and construction of new
drainage infrastructure along Tributary PEC-4 in the downtown area between Wainwright Street
at the downstream end and Bernard Street at the upstream end. The project is being designed and
constructed in phases. After all phases of the project are complete, the floodplain associated with
Tributary PEC-4 in the downtown area will be contained inside the proposed box culverts
underground. All buildings and property currently located in the floodplain of PEC-4 will be
removed from the floodplain allowing redevelopment and new construction to occur without
restrictions associated with floodplain issues.
BACKGROUND:
The overall goal of the PEC-4 Drainage Improvements project is to contain the flows from a
100-year storm event inside a new culvert system underground. This is needed because the
existing open channels along the tributary do not have sufficient water carrying capacity and are
in various stages of deterioration. Also, this will allow the City of Denton to process a Letter of
Map Revision through FEMA to remove the PEC-4 floodplain from the downtown area.
Phases 1 and 2 of the PEC-4 Drainage Improvements project were funded as part of the sale and
delivery of $7,065,000 in certificates of obligation (COs) on October 2, 2007 for the construction
of drainage improvements throughout Denton. This occurred in response to the big flood in April
of 2007 that affected the City of Denton and the downtown area. The FY2007–FY2008 budget
included a one cent tax increase per $100 of property valuation to support issuance of the COs.
A preliminary design of all phases of the PEC-4 project from Wainwright Street to Bernard
Street was completed in August of 2008. Also, a Conditional Letter of Map Revision (CLOMR)
for all phases of the project was processed through FEMA and was approved in September of
2009. The approved CLOMR from FEMA provides assurance that the PEC-4 floodplain will be
removed from the official FEMA Flood Insurance Rate Map if the proposed drainage
improvements are constructed as described in the CLOMR document.
Phases 1 and 2 of the PEC-4 Drainage Improvements project extend from Wainwright Street to
Prairie Street. The City of Denton hired Freese and Nichols, Inc. in June of 2009 to move forward
with final design of phases 1 and 2. Completion of design of the project has been delayed by
multiple reasons including bundling of the project with adjacent utility projects and TxDOT
permitting issues associated with Locust Street and Elm Street. Design of the utility projects is
now almost complete, and the TxDOT permits have been approved. Final plans and specifications
for phases 1 and 2 of the PEC-4 project are anticipated to be completed by January of 2018, and
construction is expected to begin in April of 2018
Date: November 3, 2017 Report No. 2017-081
Phases 3 and 4 of the PEC-4 Drainage Improvements project extend from Prairie Street to Bernard
Street. Design of phases 3 and 4 is expected to commence at the end of this year in December of
2017 as soon as funding has been identified.
DISCUSSION:
There are approximately 140 structures located in the floodplain of Tributary PEC-4 upstream of
Bell Avenue. 45 of these structures are associated with phases 1 and 2 of the project, and 95 are
associated with phases 3 and 4. The limits of the existing floodplain are shown on Attachment 1.
The floodplain upstream of Bell Avenue covers approximately 60 acres of land. Right now,
redevelopment and remodeling of existing structures in the PEC-4 floodplain area is severely
restricted because of flood protection requirements specified in our Flood Prevention and
Protection Ordinance and Development Code. Also, expansion of existing structures and
construction of new structures in the floodplain area is not allowed. Construction of all phases of
the PEC-4 Drainage Improvement project and processing of a Letter of Map Revision through
FEMA after construction will remove these 140 structures from the floodplain and will allow
redevelopment and new construction to occur without restrictions associated with floodplain
issues. Attachment 2 shows the approximate alignment of all phases of the PEC-4 Drainage
Improvement project. The floodplain after construction of all phases will be contained inside the
box culverts underground represented by the green, blue, yellow and red lines on Attachment 2.
CONCLUSION:
Finalize the design and complete construction of phases 1 and 2 of the PEC-4 Drainage
Improvements project. Identify funding and proceed with design of phases 3 and 4.
ATTACHMENT(S):
1. PEC-4: Limits of Existing Floodplain
2. PEC-4 Workmap
STAFF CONTACT:
Chad Allen, P.E., C.F.M., Deputy City Engineer
940.349.7713
chad.allen@cityofdenton.com
PEC-4: Limi ts o f Existin g Fl oo dpl ain
Str eam s
Ne w FEMA S LOM R 20 16
Pr e 20 11 N ot Inc orpor ate d
Pr e 20 11 N o t Inc or por ated
No ve mbe r 3, 20 17 0 0.09 5 0.190.047 5 mi
0 0.15 0.30.075 km
1:5,60 0