DR9101-CS 900111CAPITAL IMPROVI~ PROJECTS
F.Y. 1989-90
DRAINAGE
PRIORITY 1:
DESIGN ENGINEERING E CONSTRUCTION
a. Hill Drive (garage and house flooding)
Engineering funded and on-going
Construction funds needed $ 40,000
b. Oak Trail estimated
Total Engineering & Construction 50,000
(Yard flooding no outlet)
Sub Total: $ 90,000
PRIORI'I"f 2A:
CITY WIDE MASTER FLOODPLAIN STUDY & MG~. PLAN (ATTACHED)
(Preliminar~ Proposal)
Estimated from $80 K to $120 K
Depending Upon:
1. Full results of completion of
the Anderson Study, and
2. How many of the nine other streams
{branches) we want to study
$120,000
Would study and recoaaaend solutions and estimated costs
for the following known flooding situations:
Loch Lane/Chaddicks Culvert
Joy Matthews Drainway/Rocky Branch
Grapevine Crmek/Bill Johnson, Klans, et al
Others may be identified as we conduct these
studies, investigate further and conduct public
meetings on drainage problems.
PRIORITY 2B:
NLWE 1.
2.
Drainage Study + 11,000
Property Survey & Plan
& Floodplain Map 14,000
25,000
For a detail description of Priority 2, see next page. Note
that if it is desired to do 2A and 2B, the $11,000 would
reduced approximately 20% (+/-).
PRIORITY 3: Drainaqe Problems List (Attached)
This list of drainage problems was originally developed in
December, 1988, for consideration to expend surplus 1984
funds. The list was updated as noted on June 27, 1989, removing
funded projects. This list of Capital Improvement Projects was
developed by the Department of Public Works via a highly
sophisticated rating system as show. Total $795,000
GRAND TOTAL: $1,030,000 (+/-)
CAPITAL IMPROVEMENT PROJECTS
F.Y. 1989-1990
DRAINAGE (Cont.)
DESCRIPTION OF ITEM 2 Natural or earthen creeks end drainweys will
probably always be stabilizing, that is, eroding end changing its channels
and banks. We must either control the flow of water end/or improve the
channels to preclude erosion and the changing channels and banks. This
would be true even if the City of Coppell development designed for the 100
year flood waters at 'ultimate' development from the beginning.
Therefore, we must have engineering done that estimates the flows of each
and every creek and/or drainway we want to manage or stabilize. The Carl
Anderson study that is scheduled to be completed this year will provide us
information for one development scenario, (i.e. maximum reclamation by
lining the three major creeks in Coppell, approximately 22 miles). There
are nine other sizable branches not studied by Carl Anderson. These
branches would include the problem areas for Joy Matthews (Rocky Branch),
Loch Lane (Chaddick's culvert), Grapevine Creek (Meadowcreek residents
such as Klaus, Johnson, et al) and others.
This proposal for floodplain management studies and plans would provide us
solutions with cost estimates for flooding in developed areas and policy
to guide development related to what kind of design end improvements are
needed in the creeks and drainways to accomsodate the 'ultimate 100 year
design floods' in undeveloped areas.
Attached are listed the major priorities for drainage of storm water
management in the City of Coppell. There are other undesirable storm
water flows such as Mr. Mallison of 625 Swan, where his yard is eroded to
a minor extent occasionally, and the Public Works list of needed drainage
improve~aents totalling a cost of $795,000 (Included in this CIP portion of
the Budget). These situations are not as high a priority as the garage
end house flooding, or where massive creek banks are eroding. In addition
to the Pelican/Bethel School Road local drainage improvements identified
last July, 1988, end funded in December, 1988, there ia still to he funded
the Hill Drive and Oak Trail improvements that will relieve the flooding
of garages and houses, and major flooding in backyards without an outlet.
After those fixes, eliminating damage to property ~nd threats to life
safety, there is the priority of getting a handle on a management pellcy
for City wide drainage, so that we can either fund i~provements for the
elimination of existing flooding or provide policy for new private
development in the undeveloped parts of the City of Coppell.
Please note that the Anderson Study only provided the existing floodplain
based on Fl/MA information of the 1970'a, and the proposed floodplain,
based on ultimate development with maximum allowable reclamation of the
floodplain. The Anderson Plan data and infor~mtion has been used by
design engineers for developn~nt in and around the floodplain for the last
few years. The data, information and results bas not been cos~lled and
presented for any policy review and decision making. For example, it muy
be that we are using flows to achieve the passing of the 100 year storm
that requires lining of the creeks. If that required lining is not
desired by the Homeowners, or is Just not lined then higher flood waters
may result. We just don't know until we compile and analyze the Anderson
Report. To attain flows needed, we may have to remove many stands of much
needed hard woods, trees, etc.
What is needed is a Floodplain Management Plan, so we can analyze a
floodplain at ultimate development conditions end then propose
improvements (if necessary) to continue protecting existing public and
private improvements, and non floodplain property. In some places, like
Joy Matthews property, Loch Lane and Bill Johnson's property, we may need
alternatives to arrest possibly increasing flood waters, and/or reduce
them with cost effective improvements.
Additionally, Floodplain management must address 'Valley Storage', that
is, the displacement of water caused by reclamation of floodplains. Carl
Anderson's study did not take valley storage into account, because it
wasn't considered then. Valley storage considerations have Just become
necessary in the last few years.
This write-up was composed in a conservative manner with like examples to
exhibit why we need to have a complete management handle on the City of
Coppell's floodplain.
At this point in time, Staff doesn't feel that it is enough to have the
proper direction toward resolving flooding or decreasing increasing water
levels. We may save millions of dollars of retrofitting improvements
later by proper and better managed development now.
Proposed preliminary scope of work for the City-wide Floodplain Management
Study & Plan Development as presented:
A. Review/revise (R/R) Rydranlics
4 Major Tributaries (22.9 miles)
B. R/R Hydrology
4 Major Tributaries (22.9 miles)
C. R/R Master Plan
4 Major Tributaries (22.9 miles)
D. 9-Streams/5.7 miles
Do Floodplain Management Study & Plan
E. Report A thru D (50% Printing)
MAXIMUM TOTAL:
8,000
11,000
19,000
57,000
20,000
$115,000
Parts A thru C could be reduced in cost dependin~ upon the final results
Of the Anderson Study by Ron Morrison. Also, we may not went to study all
nine major br~nches rlffht now, maybe Just three or four. This will need
to be a concensus after consideration by the CMO and policy makers.
(Studies of this complexity cannot be done alone to be effective and
productive).
D~NG
Location People
3-High
DRAINAGE PROBLEMS
Degree of Affect 1-Low 2-Moderate
Categories Considered
Private Public Estimated
Property Property Health Maint. Flooding Total Coat
1. Bethel School
2. Woodridge Channel
3. Woodridge Channel
Spillway
5. Meadows.
6. Parkwood Channel
7. 721 Bethel Echonl
8. Fieldcrest Loop
9. Parkmeadow
lO.N.MacArthur
il.Moore Rd.
12.517 Arborbrook
13~Sandy Lake/George-
to~n Plaza
1
1
1
1
1
~rGTE i s
1
14.Sandy Lake/Shadydale 1
15.Sandy Lake east of
Napleleaf 1
16.Coppell Raod 1
17.Cottonwood 1
18.Denton Tap/Parkway
2 1 2 2 0 9 $40,00r ~)0
2 0 2 3 0 9 $560,00b
.%0
I 0 2 3 0 8 $20,000.00
2 2 0 0 3 ~ e~ 999.00
1 2 0 1 2 8
2 0 2 2 0 7 $91,000.00
0 ? 0 0 2 5 ~ee Pelican
0 1 1 1 0 4 $25,000.00
1 0 I I 0 4 $25,000.00
0 1 1 1 0 4 development
1 ~ 0 1 2 0 5 $5,000.00
1 1 0 1 0 4 $3,000.00
primarily affected and is trying to remedy
1 1 0 0 0 3 $2,000-00
0 0 1 1 0 3 $4,00~ )0
0 0 1 1 0 3 $1,000.00
0 0 1 I 0 3 $15,000.00
0 I 0 i 0 3 $&,000.00
currently by Denton Tap Project
*being remedied
TOTAL .........
6-27-89-BALANCE OF PROJECTS ............. $795,000.00
The priority ranking of these drainage problems is purely subjective in that the degree of at'fWL%~iT~
based on field experience and Judgement. None of these are being presently considered for authorization
with the exception of Pelican.