PA9702-CS 99010601/06/99 16:54 FAX 214 739 0~1~
""" Ba]ff Assoeiates, Inc.
ENGINEERS ARCHITECTS SCIENTISTS PLANNERS SURVEYORS
8616 Northwest Plaza Drive
Dailas, Texas 752254292
(2t4) 3466200
Fax (214) 739-0'i08
TO:
FAX #:
FROM:
FAX TRANSMITTAL
~b'. Ken Grillin, P.E., DATE: January 8, 1999
CiI~ Engineer, A~ismnt L""it7 Meaager, Director of Public Works
255 Parkway Boulevard
City of Coppall Engineering Dept.
Coppall, TX 75019
972-304-3570
Sabine Borgnet-Harris
Ema~?; sharris@halff. com
AVO: 16521
PROJECT: t)~
Andrew Brown Jr Park (East)
Fill Permit - Phas;~ I
# OF PAGES 5 (including cover sheet)
5~3 URGENT
[] PLEASE REPLY
[] FOR REVIEW
COPY TO FOLLOW BY MAIL:
[] YES {~} NO
ITEMS SENT:
COMMENTS:
1 - one 8.5 x 11 map (plan) showing the proposed mitigation at the Aquatic and Recreation Center.
2 - one cross-section plot at the mitigation area (HEC-RA.S cross-section 29831 )
Dear Mr. Griffin:
The attached plan shows the mitigation necessary to ofTset the effect of constructing the Aquatic and Recreation
Center at Andrew Brown Jr. Park (East). This scheme results in an insignificant rise in water surface elevation of
only 0.03 if, which we hope is acceptable as it is confined to one cross-section within the park itself. Please take
the time to review this design. If it is satisfactory, please let us know at your earliest convenience, This mitigation
plan was previously sent to Mr. Brad Reid, who approved it. If you have any question, please call me at 214-346-
6226. Thank you,
SIGNED: Sabine BOrgnet-Harris
NOTE: The ~omments on and attachment to this cover sheet are intended o~Jy for the use of the individual 0¢ entity to which It I~
addressed. and may contain InformatJo,1 bat is priviIegscl. csn'~clanlial. and exempt from discJosure under appllcal)le law. If the reader
or this rne_~ai;e is not the intended rodpicnic, or the employee or agent resp~sibhe for delivering the message to the intended recrp~ent,
you are hereby notlf~ed that any dissemina~jon, distribution. or copying of this communIGatio~q is stocUy prohibited. If yOU have received
Table t - Andrew Brown Jr. Park East
Flood Plain development Permit
Comparison Table of 100-year Water Surface E|evations [ft.] & Valley Storage [ac.ft._]
100-Year Flood Ultimate Landuse Watershed
L~cation
IO0-YR
Section WSEL
:~ 452.43
~?~: ¢ 462,~7
~'1~; 452,57
Revised E~jsting Conditions Reposed Condi~lions 1- Architects' Design
based on 1998 Aerlar topography Recreation Center with no mitigation
HEC-RAS FIEC-RAS
Plan P02 Geo~rrtetnJ G02 Flow F61 Ran P03 Geometry GO3 Row F01
Vii Iey 160-YR Valley
Rise~ Storage WSEL Risea Storage
~_~3~~= 452.73
%~_~ 453.46
~ 453.90
~I~ 454.05
~ ~.~.~.~'~ 454..,=?
..... :~E;' 4:~,:'~.'
..... ~E~e; = · ~ .:~
........ :.7~Y4~:".;r/z ::::
.; 2 ~;'~':' ~ ~' ' ......
0.00
220,22
437,83
693.72
785,63
91667
98505
1048.80
1112,60
· 3' '.' ' '!
.., ,,
15:~.,~?
Increasea Section
~_,8:~E]_~;_~' 452,43
452.57
452.57
452.73
~_~_ ~ 452.95
~ 453.45
~_4~;~ 453.94
1~'26~''. .-. :.r~r~ '.l~
.. _;~r...; .... . .....
- '21~55-~ .;~ :..,. .... .
. __ _~, ....
._ ,L~,~T~4~i',: .
:;~745 ' .:~( ' '
'7" E"~F~' ~: ....
, .. '~...: .- .
Increasea
QO0
22622
43783
693.72
785.63
91667
985.05
1648.80
"?" 95
'~77 9,
i.~,a ,.~
142 % ' b
Proposed Conditions 2 - Halff Design
Mitigation Plan
I-[EC-RAS
Ran P04 Ge~fnetry G04 Flay
I(30-YR Valley
Section
2,i~1::
.-.~-.,:~;~-7.
WSEL Rise 4 Storage increase*
452.43
452.57 226,22
452.57 437.83
452.73 693.72
452.95 285.63
453.46 916.67
453.94 985.05
453.90 1048.80
494.05 1112 60
454.53 1131.95
455.36 1252,02
455.42 1277.97
4~;5,91 1319.17
· ~55.00 1378.00
,;96.11 1439.38
4~.23 1506.43
"' F:fa'~:,i:, ;-~ ~:~' "" ,- 4 :.z
.:'~,.':'.:;~r..P,nj.~;~" ~',t,~,.(": '-;~:.:..'.2 ....;',:' ~
:.<,;,.;!::l;,,=c,?,'.!r ~;2.~5~':...I.~.:..~,;.:.-.. 'i-i.273"
;: ,"~;:._%c:I~,!::C:~'::~!'2;'6;!1 -:T;.' ::," 022 '~,;
...... 2.':.~;~.'.,'T,~57 ~': : .'4
~. I ' ..~:.bl,4~6 ' 5
........ }'.i.~.~a~ .,,.r- :.;,~""
e" i"'::15"< =,!;'' .....;" ,~1[(: , 45'26' '
::;'u., :.,;, I?j .....:'~:."' 4!,~ .~ .....
,! ': "'.L. "::!~-'~'::' ~;,~.~.
:.;~'e.:.' la:~ .,.c:': ~)~ .~',,~
..... ;'il" '~;"" ;','c~:~ ~,~:
· -' "' - '-' I:
. ...........
1560.27
1641.35
1714.32
175148
1795,29
1866.96 (1.771
0.03 1890.42
1924.71 (0.38}
1963,03 (0.36}
1989.15 (0.34:
2640,15 (0.33;
2101.78 (0.31]
2120.33 (0.30]
2122.91 (O,3C
2125.06 (0.31]
2127.45 (0.30]
2179.73 (030]
2242.67 (030]
Page 1 of 2
Table 1 - Andrew Brown Jr. Park gast
Flood Plain development Permit
Comparison Table of 100-year Water Surface Elevations [fL1 & Valley Storage [ac.~t.l_
tOO-Year Flood Ultimate Landuse Watershed
Location
Revised Existing Conditions Proposed Conditloe~s ~- Architects' Design
based on ~98 Aerial topography Recreation Center with no mitigation
HEC-RAS HEC-RAS
Rain P02 Geomelry G02 Flow F(~I Plan P03 Geometry G03 Flow F01
IO0-YR Valley 1OO-YR Valley
Section WSEL Rise2 Storage Increase~ Section WSEL RIse~ Storage Increase3
~ 463.81 (0.02) 2285.87 (28.54)~=._3S4.~Cr9;~ 463.81 2285.47 (0.40)~--~ 483.81
~_;~;~ 464.20 (0.02) 2385.64 (28.85)~r~eQ~ 464.20 2385.22 (0.42)~3~r,~.~ 464.20
~ 464.47 (0.02) 2451.12 (2907)~, 464.46 (0,01) 2450.69 (0.43)~ 464.~7
~ 4c>4.98 (0.ol) 2484.28 (29.13) ~ 464,98 246385 (0.43) ~,~ 484.98
~ 468,66 2760.49 (29 93) ~_~_'~ 466.66 276004 (0.45)~'~-~;_' 466.6S
~'~ tO.C,11 2939.63 (30.03) ~'(E0~-~ 467.37 2939.17 (0.46) L~:]~8~.~. 467.3,?'
~, 467.37
~_gL~_~ 46T.65 (0.01) 3t45.80 (30.11)~9F~_~, 467.85 3145.34 (0,46)~_ 467.65
~ 467.43 3174.93 (30.11)::-~;~ 467.43 3174,46 (0.47)~'_'~,~,~ 467.43
Compared to Existing Conditions, HEC-2 model (not shown)
Compared to Existing Conditions, HEC-RAS model (not shown)
Compared to Revised Existing Conditions, HEC-RAS model
Compared to Revised Existing Conditions, HEC-RAS model
1/4~99 'f 3:47
File: i:~avo~,16521~hec?%FDmedef~FD-wselxts
Rise
Rise
Rise
Rise
Proposed Conditions 2 - Halff Design
Mitigation Plan
HEC-RAS
plan P04 Geonnelry ~ Flow FOl
t00-YR Valley
Section WSEL Rise4 Storage
2285.57 {0.30:
2385.33 {0.3f
2450.81 (0.31
2463.97 (0.31
27C~0.18 (0.31
293931 (0,32
3145.48 (0.32):
3t74.61 (0.32)
Pa~e 2 of 2
ABPE - FP Development Permit Proposed lake enlargement 1/4/99 12:10:41 PM
RS = 29831
.07 ~l~ - .045 >k ,035 >(~)~c .04
............... : ~ : / Z ,::....:,.
::Ex~vatien eSigne :
................ ~ .L..,:
......... : "~ --~ ~ · .
454
~ ............................. . ,.
~ ................. . A~itiOnal mffig~[on for
"~ .....:"~"":: "'~ ~'~
1600 1800 2000 2200
SGiOa (if)
1 in Horiz. = tO0
WS PF#4
Gfourmd
Ineff
Bank
EX
TREE LINE
FOR MITiGATiON
LAKE
FOR MI1 IGATION
!,,