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Windsor Estates-SY020301REQUEST FOR A LETTER OF MAP REVISION On DENTON CREEK In the City of Coppell Dallas County, Texas WINDSOR ESTATES AND DEFOREST COURT Prepared for: COPPELL OPTIMUM ASSETS, L.L.C. By: Halff Associates, Inc. 8616 Northwest Plaza Drive Dal~25 This document is ~r ~tting purposes only and is not intended for Bidding or Construction. AVO 17669 March 1, 2002 Halff Associates ENGINEERS · ARCHITECTS · SCIENTISTS PLANNERS · SURVEYORS 8616 NORTHWEST PLAZA DRIVE DALLAS, TEXAS 75225 (214) 346-6200 FAX (214) 739-0095 Federal Emergency Management Agency C/O PBS&J, Inc. 12101 Indian Creek Court Beltsville, Maryland 20705 March 1, 2002 AVO 17669 Attn: Mr. Joe Martinenza Acting Study Manager, FEMA Region VI Request for a Letter of Map Revision on Denton Creek in the Windsor Estates/Deforest Court of the City of Coppell, Dallas County, Texas Dear Mr. Martinenza: Enclosed you will find a technical report that evaluates floodplain fill in the right overbank along Denton Creek in the Windsor Estates/Deforest Court Site, Dallas County, Texas. These features were constructed in 2001. The report contains the technical data required for issuance of a Letter of Map Revision to reflect the corrections to the effective Flood Insurance Study analysis. Hard copies of the required HEC-2 hydraulic models, a disk containing input data files, and floodplain and floodway mapping can be found in appendices A through H. Application and Certification forms are included in Section III. The effective base FIS model was performed by Halff Associates, Inc. on September 28, 1999 and approved by FEMA on March 15, 2000 (CLOMR Case No. 00-06-276R). The map revision was based on the "As-built" surveys conducted by Magnum Survey Inc. on February 22, 2002. The revised (post-project) model indicates that no additional flooding will occur in either downstream or upstream areas due to constructed project. If you have any technical questions on this report, please contact Allen Xu or Walter Skipwith of Halff Associates, Inc. at 214-346-6200. Administrative questions should be directed to Mr. Kenneth M. Griffin, P.E., Director of Engineer and Public Works, for the City of Coppell at 972- 304-3679. Thank you for your consideration of this request. Yours very truly, HALFF ASSOCIATES, INC. Walter E. Skip 'itl~, P.E. Vice-President Enclosures cc: Mr. Jack Quarles, FEMA Region VI, Denton, Texas. Mr. Kenneth M. Griffin, P.E., Director of Engineer and Public Works Mt. Kelly Jordan, Coppell Optimum Assets, LLC File: l:\ 17000s\ 17669\lomrck669LOM R_rpt.doc DALLAS · FORT WORTH · HOUSTON · McALLEN TRANSPORTATION · WATER RESOURCES o LAND DEVELOPMENT · MUNICIPAL · ENVIRONMENTAL o STRUCTURAL -- MECHANICAL · ELECTRICAL · SURVEYING · GEOGRAPHIC INFORMATION SYSTEMS ARCHITECTURE · LANDSCAPE ARCHITECTURE ' PLANNING FEMA LOMR STUDY OF DENTON CREEK ON THE WINDSOR ESTATES/DEFOREST COURT TABLE OF CONTENTS INTRODUC~ON A. General B. Objectives of the Study Scope of the Study D. Hydrology E. Hydraulics 1. Effective Models Duplications 2. Corrected Effective Models 3. Revised (Post-project) Models F. Conclusions Page # 1 2 2 2 2 3 4 7 8 FIGURES AND IVIAPS ]]][. APPLICATION AND CERTIIqCATION FORMS MT-2 FORM 1 REVISION REQUESTER AND COMMUNITY OFFICIAL MT-2 FORM 4 RIVER HYDRAULIC ANALYSIS MT-2 FORM 5 R1VERINE/COASTAL MAPPING IV. PHOTOGRAPHS Vo FEMA LOMR STUDY OF DENTON CREEK ON THE WINDSOR ESTATES/DEFOREST COURT TABLE OF CONTENTS~ CONTINUED APPENDICES Appendix A Appendix B Appendix C Appendix D Appendix E Appendix F Appendix G Appendix H Revised Existing Cross-Sections FIS Duplicate Effective Multi-Profile HEC-2 Model: forest.dat ]TIS Duplicate Effective Floodway HEC-2 Model: 4rstfwy.dat Corrected Effective Multi-Profile HEC-2 Model: rvexd4st.dat Corrected Effective Floodway HEC-2 Model: rvxfdwy.dat Revised (Post-project) Multi-Profile HEC-2 Model: 7669remk.dat Revised (Post-project) Floodway HEC-2 Model: 7669fwyk.dat Digital HEC-2 Input Data Files on Disk FEMA LOMR STUDY OF DENTON CREEK ON THE WINDSOR ESTATES/DEFOREST COURT LIST OF FIGURES AND MAPS IN APPENDIX A Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Location Map Effective and Revised FIRM Floodplain Map "As-built" Survey Map for DeForest Court "As-built" Survey Map for Windsor Estates Revised Swale Grading Plan for Windsor Estates Multiple Flood Profile FEMA LOMR STUDY OF DENTON CREEK ON THE WINDSOR ESTATES/DEFOREST COURT Table 1 Table 2 LIST OF TABLES Comparison of Water Surface Elevations - 100-Year Discharges Comparison Table of Manning's "n" Values Page I-8 I-9 FEMA LOMR STUDY OF DENTON CREEK ON THE WINDSOR ESTATES/DEFOREST COURT I. Introduction A. General Windsor Estates and Deforest Court are single-family residential developments along the right bank of Denton Creek in Coppell, Texas. Windsor Estates is located at the end of DeForest Road on 15.8 acres of land, and approximately 3.10 miles upstream from the confluence of Denton Creek with the Elm Fork of the Trinity River. DeForest Court is located on the north side of DeForest Road on 8.4 acres of land, and just upstream (approximately 300 feet) from Windsor Estates (see Fig 1). Denton Creek is one of the major streams in the North Central Texas Area. It and its tributaries drain 719 square miles with 695 square miles of drainage area being controlled by the flood control dam at Lake Grapevine. Below the dam, Denton Creek flows in an easterly direction through the Cities of Grapevine, Lewisville, Carrollton, and Coppell before joining the Elm Fork of the Trinity river just upstream of Sandy Lake Road. Denton Creek in the project area is approximately 110 feet wide (bank to bank) at the downstream end (Windsor Estates), and approximately 540 feet (including the enlarged channel constructed by the Denton County Levee Improvement District No. 1 (DCLID #1) in 1985) at the upstream end (DeForest Court). Due to the size of the basin and the projects proximity to the Elm Fork of the Trinity River, the floodplain is relatively flat. For example, ground elevations nearest the creek are higher than the surrounding floodplain due to the natural levee building process the creek experienced especially before Lake Grapevine was built. Site visits reveal that the creek has eroding stream banks especially downstream of the large constructed channel, as well as a mature stand of trees along the banks. Water quality is relatively good. Photographs on pages IV-1 through IV-3 illustrate existing conditions for each site. B. Objectives of the Study The objective of this study is to update floodplain information for Denton Creek through the Windsor Estates/Deforest Court Site based on existing (2002) conditions and update the current FIRM with a Letter of Map Revision. C. Scope of the Study This study covers the Denton Creek floodplain between Section 0 (approximate 5000 ft downstream from Windsor Estates) and Section 223+70 (approximate 2500 ft upstream from Deforest Court). Topographic maps were provided by City of Coppell. The floodplain information presented in this report is based upon the effective FIS discharge and revised geometric data for the existing creek. D. Hvdrolo~Tv Effective FIS study discharges were based on for this study. The 10-, 50-,100-, and 500-year flood peak discharge at the effective section 18440 (downstream boundary) in the hydraulic model are 12800 cfs, 18200 cfs, 20600 cfs, and 36200 cfs. Through left bank flood diversion, the actual discharges in Denton Creek channel are 8340.4 cfs, 9670 cfs, 10277.1 cfs and 14161.4 cfs respectively. This is discussed in more detail under next section, E. Hydraulics. 1~. Hydraulics Analyses of the floodplain and hydraulic characteristics of study area were performed using the USACE's HEC-2 program. The original model was based on the 1999 HEC-2 model prepared by Halff Associates, Inc. for the CLOMR application on the same site. In this study, the "As-built" survey data is used to update effective cross sections in the model. The downstream model boundary condition was established based on the existing 1999 model. Locations of selected cross sections used in the hydraulic analyses are shown on the floodplain map (see Figure 3). Channel cross-sections are shown on Appendix A. Reference Mark 472.06 (NAVD) is located at southwest corner of Cicero Longs Lot and North side of Deforest Road. 1. Effective Model Duplications (Appendices B and C). In April 1999, the request for current effective models for the reach of Denton Creek adjacent to these projects was made to Mr. Anthony Appleby with the FEMA Project Library. In May 1999, through Mr. Venkataiah Venkatraj with the FEMA Project Library, hard copies of the effective floodplain (also known as natural or multi-profile) model and the floodway model were obtained. Upon investigation, it was determined that the current effective floodplain model received did not match the model used in LOMR for Cambridge Manor (by Dowdey, Anderson & Associates, Inc., 3/29/95, Case #: 95-06-019P) or the LOMR for DeForest Road (by Halff Associates, Inc., July 23, 1997, Case #: 97-06-503P). Therefore, it was determined that the floodplain model received from the FEMA Project Library was not the current effective model, and that the model used for the previous mentioned LOMR's should be the effective model used for this study. A duplicate effective model, FOREST. DAT, was created from the hard copy model, 920630PR. DAT, by entering the model data into the U.S. Army Corps of Engineers HEC-2 hydraulics package. The current effective floodway model, 92063ENC. DAT, was obtained from FEMA. Investigations of this model revealed that it had minor differences compared to the current effective floodplain model. At section 18440, GR points differ between the models from Station 5850 to the end of the cross-section on the right overbank. For section 19330, GR points differ between the models from Station 6435 to the end of the cross-section on the right overbank. At these sections, the GR data of the floodway model was replaced with the GR data from the effective floodplain model to create the duplicate effective floodway model: 4RSTFDWY. DAT. Execution of duplicate effective floodplain and floodway models resulted in minor differences when compared to the current effective models. Due to computational differences between the current effective and duplicate effective floodplain models, a 0.01 decrease in the 500-year water surface elevation resulted at cross- section 30570. For the comparison of the floodway models, a maximum rise of 0.02 occurred between cross-section 19930 and 22370 of the duplicate effective floodway model. This is most probable due to the changes to the GR points mentioned above at cross-sections 18440 and 19300. The duplicated effective multi-profile HEC-2 model results are shown in Appendix B and the effective floodway model results are shown in Appendix C. 2. Corrected Effective Model (Appendices D & E) Corrected effective models were developed by Halff Associates. In the current effective model, there were no FIS cross-sections downstream of section 18400. Because of the project (Windsor Estates) location along Denton Creek and the large distance (3.5 miles) to the Elm Fork of the Trinity River, the effective model was extended downstream by adding 10 cross-sections. Other cross-section changes to the model included the removal of FIS cross-sections 18440 and 19330, and the addition of new sections in the area where these FIS sections were and in upstream areas. Apparently, these new sections were based on best available topography at the time and channel (bank to bank) information provided by the U.S. Army Corps of Engineers. Another important change to the current effective model, was the addition of a split flow by weir analysis in the left overbank area. The weir is actually a private road used by a local gun club. Elevations of the road range from 458.1 at the top of the levee to 450.3 at section 1.1. Flood events overtop this embankment providing an area for flood waters to pass directly from the Denton Creek floodplain into the Elm Fork of the Trinity River floodplain. The following additional changes were made: · On December 30, 1998, Halff received new City of Coppell topography. Right overbanks of all cross-sections that were added to the effective model were adjusted per this new topography. · Cross-sections in the area of the roadway weir were cut off at the weir instead of extended to the north to end at an existing levee. · On cross-sections 12 through 14, the left overbank was blocked for ineffective flow and conveyance reasons. · Initially, the model was started with a cross-section and a known water surface elevation from the Elm Fork of the Trinity River model. Using the slope between the water surface elevations of the Elm Fork of the Trinity River and the first section of Denton Creek, the corrected effective and revised (post-project) conditions models were started by the slope-area method at the first section on Denton Creek. The addition of the DeForest Court project resulted in the following changes: · Cross-sections 19647 was copied from cross-section 14 and the non- effective flow limit (X3) was adjusted on right overbank. · Adjusted the channel reach length and overbank lengths on FIS cross- section 19930. · Cross-sections 19770 and 20025 was copied from FIS cross-section 19930 and the non-effective flow limits (X3's) were adjusted on right overbank · Adjusted the channel reach length and overbank lengths on FIS cross- section 20980. WINBSOIa ESTATES/!~}~{FO~S~! ?;T C~C ~Ji;IT' In general, the corrected effective (existing) conditions model resulted in a rise over the duplicate effective model (see Table 1) for the 100-year flood. These rises are due to the additional detail incorporated into the model to accurately reflect the constructed development. This updated model was the basis for the hydraulic modeling of the post project development discussed in the following section. The duplicate effective floodway model was also revised to match the corrected effective floodplain model. For the floodway model, the split flow 100-year discharge calculated in the corrected effective model at each cross-section between 0 and 12 was used. Section 13 was the last cross-section in which the full FIS discharge of 20600 cfs is conveyed across the section before the split flow over the Gun Club Road. A map of the corrected floodplain and floodway (see Fig 2) has been included in this report. The map was created from the Dallas County, Texas and Incorporated Areas, FIRM 48113C0155 J, August 23, 2001. In our review of this new FIRM, we note some discrepancies in the way the floo0way for Denton Creek is drawn compared to previous FIRM's. The previous floodway followed the levee on the north overbank (sections 20025 through section 13) of Denton Creek and joined the Elm Fork of the Trinity River Floodway at the road/weir location shown. By placing the floodway where it shown on the current map, the road acting as a weir would be blocked off causing all 20600 cfs to flow down Denton Creek. lhis floodway alignment will cause downstream rises greater than 1 foot along Denton Creek. Finally, the corrected effective multi-profile model results are shown in Appendix D and the corrected effective floodway model results are shown in Appendix E. 3. Revised (Post-proiect) Models (Appendices F & G). Constructed improvements to the sites are reflected in the corrected effective model to create a post project model. The geometric data in revised models are based on the construction plans and "As-built" survey data (see Fig 4 for DeForest Court and Fig 5 for Windsor Estates). Modifications to the corrected effective model consist of the following: 1). Approximately 8-acres of land from the 100-year floodplain has been reclaimed by fill for Windsor Estates. Excavation of a pond and a swale are also part of this site. Fill and excavation at this site occur at cross-sections 6 through 14. Furthermore, a 120'x60' Tennis Court is proposed between Section 9 and 10 with slab elevation 452.5. A retaining wall along with creek side of the tennis court is proposed to make space for swale and valley storage (see Fig 6). 2). An approximately 5.9-acres of land from the lO0-year floodplain has been reclaimed by fill for DeForest Court. Excavation of a storage pond is also required here for valley storage preservation. Fill and excavation at this site extend from cross-section 19647 through 20025. 3). Manning's "n" values have been lowered on right overbank reflect the constructed swale (see Table 2). 4). Ineffective flow areas have been adjusted on the right overbank. The corrected effective floodway model was upgraded to match the revised (post- project) floodplain model. At those locations in which the lO0-year floodplain was narrower than the floodway, floodway stations were adjusted to be coincident with the lO0-year floodplain limits. As a result, the revised (post-project) multi-profile model results are shown in Appendix F and the revised floodway model results are shown in Appendix G. '- HA~F/kSSOC~A'F15S~ INC 7 W!NDSOR ESi'A/ES/DEFOREST COURT LOMR F. Conclusions This LOMR application reflects swale, detention pond and floodplain alterations to Denton Creek on City of Coppell property. The changes were constructed in 2000- 2002. The final results of the revised (post-project) multi-profile and floodway models are listed in Table 1. The comparison between the effective model and the revised existing model is also shown. The lO0-year flood delineations are shown on Figure 3. The revised (post-project) multiple flood profiles are shown in Fig. 7. The final result indicates the constructed site improvements will cause no additional flooding in either downstream or upstream of the study area. The computation results should be incorporated into the currently effective FIRM by approval of this Letter of Map Revision. W~N$OB ~ESTATE$/B~FO~ZST OOU~T LOMR II. Figures and Maps -- ItALFF A,~50C] VI'ES, ]NC 9 Figure 1: Location Map SCALI: IN MILES SCALE IN FE~' DETENTION POND AREA aox PAD 2 1X PAD I~ 16 ~x50~2× 18 ,xxsof0x1 igx DEFOREST ROAD 5050 N: 5051 N: 5052 N: 5055 N: 5054 N: 5055 N: 5056 N: 5057 N: 5058 N: 5059 N: 5060 N: 5061 N: 5062 N: 5063 N: 5064 N: 5065 N: BM SURVEYOR'S CERTIFICATE NOW, THEREFORE KNOW ALL MEN BY THESE PRESENTS: I, Joseph C. Menges, do hereby certify thot ~ prepored this plot from on octuol ground survey performed under my personol supervision, Joseph C, Menges 1" = 100' 5736.955 E: 4678.436 El: 455.221 D: PAD 11 5810.505 E: 4578510 El: 455.013 D: PAD 10 5764,159 E: 4444.283 El: 454.546 D: PAD 9 5652.765 E: 4436,255 El: 454,997 D: PAD 8 5554.489 E: 4449,110 El; 454878 D: PAD 7 5462.011 E: 4448.864 El: 454.815 D: PAD 6 5369.544 E: 4449,094 Et: 455,414 D: PAD 5 5276,921 E: 4449,096 El: 454,507 D: PAD 4 5184.492 E: 4449089 El: 455.025 D: PAD 3 5091.924 E: 4449,172 El: 454.600 D: PAD 2 5092,296 E: 4668,056 El: 455.451 D: PAD 18 5169085 E: 4671,096 El: 454,132 D: PAD 17 5276.721 E: 4668.422 El: 454.855 D: PAD 16 5369,222 E: 4668,478 El: 454.848 D: PAD 15 5462.004 E: 4668.458 El: 455,213 D: PAD 14 5554584 E: 4668.555 El: 455545 D: PAD 15 DEFOREST COURT A RE-PLAT OF LOT i & LOT B NETTIE LONG ADDITION IN THE W,A, TRIHBLE SURVEY ABSTRACT No, 1~68 CITY OF COPPELL, DALLAS COUNTY, TEXAS FROM CITY APPROVED PLA MAGNUM SURVEY ELEVATION SHOTS @ EXISTINC 6002 ~5~25 5051 WINDSOR ESTATES CITY OF COPPELL, TEXAS BM USED FROM CITY APPROVED PLANS SURVEYORIS CERTIFICATE NC~W, THEREFORE KNOW ALL MEN BY THESE PRE~ENT~: L Joseph C. Menges, do hereby certify that I prepared this plot from on actuo~ ground survey performed under my personal supervision, Joseph C, Menges Registered Professional Land Surveyor Texas Registration No. 4753 MAGNUM SURVEYINO 79t2 TULANE DRIVE ROW~ETT, TEXAS 75088 PHONE/FAX 972-472-7019 GRADE ELEVATIONS ON BLD, PADS ARE @ OR NEAI CENTER OF PAD @ AN AVERAGE EXISTING GRADE ELEVATIONS ON TOP OF CONCRETE PAVING ARE A SAW CUT @ OR NEAR CENTER OF PAVING h,,/1 A O N L.J k/1 SURVEY RANDOM ELEVATION SHOTS ALONG CENTER CONCRETE ROADWAY &: P-I F\/ATl('hh.I QIM(~TQ ¢hh, I RI Iii I~IKI~ PAnG ELEVATION ,0 IN FEET (NGVD) m III. Application and Certification Forms FEDERAL EMERGENCY MANAGEMENT AGENCY ~ O.M.B No. 3067-0148 REVISION REQUESTER AND COMMUNITY OFFICIAL ~ Expires April 30, 2001 Public reporting burden for this form is estimated to average 2.13 hours per response. The burden estimate includes the time for reviewing instructions, searching existing data sources, gathering and maintaining the needed data, and completing and reviewing the form. Send comments regarding the accuracy of the burden estimate and any suggestions for reducing this burden to: Information Collections Management, Federal Emergency Management Agency, 500 C Street, S.W., Washington DC 20472; and to the Office of Management and Budget, Paperwork Reduction Project (3067-0148), Washington, DC 20503. You are not required to respond to this collection of information unless a valid OMB Control Number is displayed in the upper right corner of this form. 1. REQUESTED RESPONSE FROM FEMA J This request is for a: [] CLOMR A letter from FEMA commenting on whether a proposed project, if built as proposed, would justify a map revision, or proposed hydrology changes (See 44 CFR Ch. 1, Parts 60,65 & 72). [] LOMR A letter from FEMA officially revising the current NFIP map to show the changes to floodplains, floodway or flood elevations. LOMRs typically decrease flood hazards. (See 44 CFR Ch. 1 Parts 60 & 65.) [] Other Describe: __ 2. OVERVIEW 1. The basis for this revision request is (are): (check all that apply) [] Physical Change [] Improved Methodology/Data [] Floodway Revision [] Other Describe: Note: A photograph is not required, but is very helpful during review. 2. Flooding Source: Denton Creek 3. Project Name/Identifier: Windsor Estates and DeForest Court 4. FEMA zone designations affected: A._~E (example: A, AH, AC, Al-A30, A99, AE, V, VI-V30, VE, B, C, D, X) 5. The NFIP map panel(s) affected for all impacted communities is (are): Community No. I Community Name State Map No. Panel No. Effective Date Ex: 480301 Katy, City TX 480301 0005D 02/08/83 480287 Harris County TX 482010 0220G 09/28/90 480170 Dallas County, Texas and Incorporated Areas TX 48113C 0155J 07130/99 6. The area of revision encompasses the following types of flooding and structures. Check all that apply. Types of Floodinq Structures [] Riverine [] Channelization [] Coastal [] Levee/Floodwall [] Alluvial fan [] Bridge/Culvert [] Shallow Flooding (e.g. Zones AC and AH) [] Dam [] Lakes [] Fill [] Other/describet [] Other/describe/Excavation for Storable Reguirements. FEMA Form 81-89 Revision Requester and Community Official Form MT-2 Form I Page 1 of 2 I 4. ENCROACHMENT INFORMATION 1. Does the State have jurisdiction over the floodway or its adoption by communities participating in the NFIP? [] Yes [] No If Yes, attach a copy of a letter notifying the appropriate State agency of the floodway revision and documentation of the approval of the revised floodway by the appropriate State agency. 2. Does the development in the floodway cause the 1% annual chance (base) elevation to increase at any location by more than 0.000 feet? [] Yes [] No [] N/A 3. Does the cumulative effect of all development that has occurred since the effective SFHA was originally identified cause the base flood elevation to increase at any location by more than one foot (or other increase limit if community or state has adopted more stringent criteria - even if a floodway has not been delineated by FEMA)? [] Yes X No If the answer to either items is Yes, please attach documentation that all requirements of Section 65.12 of the NFIP regulations have been met, regarding evaluation of alternatives, notice to individual legal property owners, concurrence of CEO, and certification that no insurable structures are impacted. 5. MAINTENANCE RESPONSIBILITY _ The community is willing to assume responsibility for [] performing [] overseeing compliance with the maintenance and operetion prans of the Windsor Estate & DeForest Court (Name) flood control structure. If not performed promptly by an owner other than the community, the community will provide the necessary services without cost to the Federal government. Operation and maintenance plans are attached. [] Yes [] No [] N/A 6. REVIEW FEE The review fee for the appropriate request category has been included. X Yes Fee amount: $3,100.00 OR This request is based on a federally sponsored flood-contrel project where 50 percent or more of the project's cost is federally sponsored, or the request is based on detailed hydrologic and hydraulic studies conducted by Federal, State, or local agencies to replace approximate studies conducted by FEMA and shown on the effective FIRM; thus the project is fee exempt. [] Yes Please see Instructions Note: I understand that m submitted correct uester Printed Name and Title of Revision Requester Coppell Optimum Assets, I_.L.C. Company Name No.: 357-0505 Date: 03/01/02 CERTIFICATION BY REGISTERED PROFESSIONAL ENGINEER AND/OR LAND SURVEYOR is in accordan~l with 44 CFR Ch. 1, Sect 65.2 ¢- .... - S~nature Walter E. Skipwith, P.E, Vice-President Printed Name and Title of Revision Requester Registr No. 48752 Expires (Date)12/31/02 State TX Type of License/Expertise: Professional Enqlneer 7. SIGNATURE Note: Signature indicates that the community understands, from the revision requester, the impacts of the revision on flooding conditions in the comm~ity. Signature of Community Official Kenneth M. Griffin~ P.E., Director of Public Works Printed Name and Title of Community Official City of Coppelll Texas Community Name 304-3679 Date: 03/01/02 Check which forms have been included with this request Form Name and (Number) Required if ...... [] Hydrologic (3) new or revised discharges [] Hydraulic (4) new or revised water-surface elevations [] Mapping (5) floodplain/floodway changes [] Channelization (6) channelis modified [] Bridge/Culvert (7) addition/revision of bridge/culvert [] Levee/Floodwall (8) addition/revision of ]evee/floodwall [] Coastal (9) new or revised coastal elevations [] Coastal Structures (10)addition/revision of coastal structure [] Dam (11) addition/revision of dam [] Alluvial Fan (12) structures proposed on alluvial fan -- FEMA Form 81-89 Revision Requester and Community Official Form MT-2 Form I Page 2 of 2 I I --~ Flooding Source: Denton Creek I Project Name/Identifier: Windsor Estates and DeForest Court _ 1. REACH TO BE REVISED I Describe the limits of the revision OR submit a copy of the FIRM with the revision area clearly highlighted. Copy of FIRM(s) attached depicting area of the revision (highlighted, or circled)? [] Yes -- Downstream Limit: Section 0 - approximately 11,300 feet upstream of the Confluence with the Elm Fork of the Trinity River Upstream Limit: Section 21260 2, MODELS SUBMITTED FEDERAL EMERGENCY MANAGEMENT AGENCY ] O.M.B No. 3067-0148 RIVERINE HYDRAULIC ANALYSIS ~ Expires April 30, 2001 PUBLIC BURDEN DISCLOSURE NOTICE Public reporting burden for this form is estimated to average 2.25 hours per response. The burden estimate includes the time for reviewing instructions, searching existing data sources, gathering and maintaining the needed data, and completing and reviewing the form. Send comments regarding the accuracy of the burden estimate and any suggestions for reducing this burden to: Information Collections Management, Federal Emergency Management Agency, 500 C Street, S.W., Washington DC 20472; and to the Office of Management and Budget, Paperwork Reduction Proiect I3067-0148t, Washington, DC 20503. You are not required to respond to this collection of information unless a valid OMB Control Number is displayed in the upper right corner of this form. Note: Fill out one form for each floodin~l source studied Community Name: City of Coppell, Texas Requirements: for areas which have detailed floodinq: for areas which do not have detailed Full input and output listings along with files on diskette for each of the models flooding: listed below (items 1-4) and a summary of the soume of input parameters used in Only the 100-year (Base) flood profile is the models must be provided. The summary must include a description of any required. A hydraulic model is not required for changes made from model to model (e.g., Duplicate Effective model to Corrected areas which do not have detailed flooding; Effective model). At a minimum, the Duplicate Effective (item 1) and the Revised or however, BFEs may not be added to the Post-Project Conditions (item 4) models must be submitted. See instructions for revised FIRM. ]fa hydraulic model is developed directions on when other models may be required, for the area, items 3 and 4 described below must be submitted. If hydraulic models are not developed, hydraulic analyses (including all calculations) for existing or pre-project conditions and revised or post-project conditions must be submitted. 1. Duplicate Effective Model [] Natural File Name forest [] Floodway File Name 4rstwy Copies of the hydraulic analysis used in the effective FIS, referred to as the effective models (10-, 50-, 100-, and 500-year multi-preflle runs and the floodway run) must be obtained and then reproduced on the requester's equipment to produce the Duplicate Effective model. This is required to assure that the effective models input data has been transferred correctly to the requester's equipment and to assure that the revised data will be integrated into the effective data to provide a continuous FIS model upstream and downstream of the revised reach. 2. Corrected Effective Model [] Natural File Name rvexd4st [] Floodway File Name rvxfdwy The Corrected Effective model is the model that corrects any errors that occur in the Duplicate Effective model, adds any additional cross sections to the Duplicate Effective model, or incorporates more detailed topographic information than that used in the currently effective model. The Correctly Effective model must not reflect any man-made physical changes since the date of the effective model. An error could be a technical error in the modeling procedures, or any construction in the floodplain that occurred prior to the date of the effective model but was not incorporated into the effective model. 3. Existinq or Pre-Proiect Conditions Model [] Natural File Name__ [] Floodway File Name__ The Duplicate Effective model or Corrective Effective model is modified to produce the Existing or Pre-Project Conditions model to reflect any modifications that have occurred within the floodplain since the date of the Effective model but prior to the construction of the project for which the revision is being requested. If no modification has occurred since the date of the effective model, then this model would be identical to the Corrected Effective model or Duplicate Effective model. 4. Revised or Post-Proiect Conditions Model [] Natural File Name 7669remk [] Floodway File Name 7669wyk The Existing or Pre-Project Conditions model (or Duplicate Effective model or Corrected Effective model, as appropriate) is revised to reflect revised or post-project conditions. This model must incorporate any physical changes to the floodplain since the effective model was produced as well as the effects of the project. When the request is for the proposed project this model must reflect proposed conditions. 5. Other- Please attach a sheet describing all other models submitted along with the file names. [] Natural [] Floodway PLEASE REFER TO THE INSTRUCTIONS FOR THE APPROPRIATE MAILING ADDRESS _ FEMA Form 81-89C Riverine Hydraulic Analysis Form MTn2 Form 4 Page 1 of 2 -I Explain how they were determined. 3. STARTING WATER-SURFACE ELEVATIONS Explanation Attached? [] Yes [] No NOTE: If the effective study is an approximate study, the slope/area method is recommended. For detailed anal~/sis studies, usin~l a known water-surface elevation is recommended. 4. RESULTS tfrom the model used to revise the 100-year water surface elevations) If the results indicate any of the following, attach an explanation - to this form, or to the hydraulic model printout- as to the reasonableness of the situation. [] Supemritical depth [] Critical Depth [] Drawdowns [] Negative Floodway Sumharges [] Floodway Sumharges Greater Than Maximum Allowed by Community/State [] Water surface elevations higher than the end points of cross sections. [] Floodway discharge is different than the Natural 100-year (base) flood discharge. [] Project causes 100-year floodplain or floodway elevations to increase (state if increases are located off the requester's property) Explanation attached with Form [] Explanation provided on attached printout [] If Hydraulic model used is HEC-2, has it been checked with FEMA'S CHECK-2 computer program? [] Yes Isee instructions for information on how to obtain CHECK-21 5. REVISED FiRM/FBFM AND FLOOD PROFILES 1. Profile Transition [] No a. 100-Year Water-Surface Elevations - indicate the difference in water surface elevations where the project 100-year elevations tie into the existing 100-year water sur[ace elevations at each end of the project. Downstream End N/A within N/A (feet) Cross-Section # Upstream End 21260 within 0.0 (feet) Cross-Section # b. Floodway Elevations - indicate the difference in water surface elevations where the project floodway elevations tie into the existing floodway water surface elevations at each end of the project. Downstream End N/A within N/A (feet) Cross-Section # Upstream End 21260 within 0.0. (feet) Cross-Section # c. Floodway widths - indicate the difference in floodway widths where the project floodway widths tie into the existing width at each end of the project. Downstream End N/A within N/A (feet) Upstream End 21260 within 0.0 (feet) Cross-Section # Cross-Section # 2. Profile Checklist (check box if information has been provided on profile) The following information (unless in parentheses) must be included at the same scale as the existing profiles for this project: [] Stream Name [] Community Name [] Confluences labeled [] Channel Stationing [] HorizontalNertical Scales indicated [] Road Crossings [] Labeled [] Corporate Limits labeled [] Streambed profiled [] 100-year elevs profiled* [] Low Chord Elevations [] Study limits labeled [] Cross Sections labeled *All recurrence intervals in the effective study must also be profiled. [] Top of Road Elevations Floodway Data Table Attach a Floodway Data Table for each cross section listed in the published Floodway Data table in the FIS report. Floodway Data Table Attached [] Yes [] Not Required FEMA Form 81-89C Riverine Hydraulic Analysis Form MT-2 Form 4 Page 2 of 2 FEDERAL EMERGENCY MANAGEMENT AGENCY O.M.B No. 3067-0148 RIVERINE ! COASTAL MAPPING Expires April 30, 2001 PUBLIC BURDEN DISCLOSURE NOTICE Public reporting burden for this form is estimated to average 1.5 hours per response. The burden estimate includes the time for reviewing instructions, searching existing data sources, gathering and maintaining the needed data, and completing and reviewing the form. Send comments regarding the accuracy of the burden estimate and any suggestions for reducing this burden to: Information Collections Management, Federal Emergency Management Agency, 500 C Street, S.W., Washington DC 20472; and to the Office of Management and Budget, Paperwork Reduction Project (3067-0148), Washin¢ DC 20503. You are not required to respond to this collection of information unless a valid OMB Control Number is displayed in the upper right corner of this form. Note: Fill out one form for each floodin{7 source studied Community Name: City of Coppell, Texas Flooding Source: Denton Creek Project Name/Identifier: Windsor Estates and DeForest Court Thisisa [] Manual [] Digital submission. Digital map submissions may be used to update digital FIRMs (DFIRMs). For updating DFIRMs, these submissions must be coordinated with FEMA Headquarters as latin advance as possible. 1. MAPPING CHANGES 1. A topographic workmap must be submitted showing the following information (check N/A when not applicable): a. Revised approximate 100-year floodplain boundaries (Zone A) ............................................................... [] Yes [] No [] N/A b. Revised detailed t00- and 500-year floodplain boundaries ..................................................................... [] Yes [] No [] N/A c. Revised floodway boundaries ................................................................................................................... [] Yea [] No [] N/A d. Location and alignment of all cross sections with stationing control indicated ........................................ [] Yes [] No [] N/A e. Stream alignments, road alignments and dam alignments ...................................................................... [] Yes [] No [] N/A f. Current community boundaries ................................................................................................................ [] Yes [] No [] N/A Effective 100- year floodplain and floodway boundaries from F]RM/FBFM reduced or enlarged to the scale of the topographic workmap ................................................................................... [] Yes [] No [] N/A h. Tie-ins between the effective and revised 100-, 500-year and floodway boundaries ................................ [] Yes [] No [] N/A i. The requester's properly boundaries and community easements ............................................................ [] Yes [] No [] N/A j. The signed cedification of a registered professional engineer .................................................................. [] Yes [] No [] N/A k. Location and description of reference marks ............................................................................................ [] Yes [] No [] N/A I. Vertical datum (example: NGVD, NAVD) ................................................................................................. [] Yes [] No [] N/A m. Coastal zone designations tie into adjacent areas not being revised ....................................................... [] Yes [] No [] N/A n. Location and alignment of all coastal transects used to revise the coastal analyze ................................. [] Yes [] No [] N/A o. V-zone has been delineated to extend landward to the heel of the primary frontal dune ......................... [] Yes [] No [] N/A If any items are marked No or N/A please attach an explanation. 2. What is the source and date of the updated topographic information (example: orthophoto maps, July 1985; filed survey, May 1979, beach profile, June 1987 etc.)? March 1998 City of Coppell Topqraphic Maps and Feb. 1991 Trinity River Topoqraphic Maps 3. What is the scale and contour interval of the following workmaps? Effective FIS Scale 1"=1000 ft Contour Interval 10 ft Revision Request Scale 1"=200 ft Contour Interval 2 ft NOTE: Revised topographic information must be of equal or greatar detail than effective. 4. Attach an annotated FIRM/FBFM at the scale of the effective FIRM/FBFM showing the revised 100- and 500-year floodplain and the floodway boundaries and how they tie into those shown on the effective FIRM/FBFM downstream and upstream of the revisions or adjacent to the area of revision for coastal studies. FIRM/FBFM attached? [] Yes [] No PLEASE REFER TO THE INSTRUCTIONS FOR THE APPROPRIATE MAILING ADDRESS FEMA Fon'n 81-89D Riverine/Coastal Mapping Form MT-2 Form 5 Page 1 of 2 2. EARTH FILL PLACEMENT The fill is: [] Existing [] Proposed Has fill been/will be placed in the regulatory floodway? If Yes, please attach completed Riverine Hydraulic Analysis Form (Form 4). Has fill been/will be placed in floodway fringe (area between the floodway and 100-year floodplain boundaries)? If Yes, then complete A, B, C, and D below. [] Yes [] No [] Yes [] No Are fill slopes for granular materials steeper than one vertical on one-and-one-hail horizonlal? [] Yes [] No If Yes, justify steeper slopes __ Is adequate erosion protection provided for till slopes exposed to moving flood waters? (Slopes exposed to flows with velocities of up to 5 feet per second (fps) during the 100-year flood must, at a minimum, be protected by a cover of grass, vines, weeds, or similar vegetation; slopes exposed to flows with velocities greater than 5 fps during the 100-year flood must, at a minimum, be protected by stone or rock riprap.) [] Yes [] No If No, describe erosion protection provided __ Has all fill placed in revised 100-year floodplain been compacted to 95 percent of the maximum density obtainable with the Standard Proctor Test Method or acceptable equivalent method? [] Yes [] No Can structures conceivably be constructed on the fill at any time in the future? [] Yes [] No If Yes, attach certification of fill compaction (item 3c. above) by the community's NFIP permit official, a registered professional engineer, or an accredited soils engineer in accordance with Subparagraph 65.5(a)(6) of the NFIP regulations. Fill certification attached [] Yes [] No Has fill been/will be placed in a V zone? [] Yes [] No If Yes, is the fill protected from erosion by a flood control structure such as a revetment or seawall? [] Yes [] No If Yes, attach the Coastal Structures Form (Form 10). FEMA Form 81-89D Riverine/Coastal Mapping Form MT-2 Form 5 Page 2 of 2 03/15/00 15:44 FAX 214 739 0095 HALFF ASSOCIATES [~010/_013_ Federal Emergency Management Agency Washington, D.C. 20t72 HAR 1 5 2 00. CERTII~IED MAIL RETURN REC~irl' REQuESTED IN [~EPLY REFER TO: Case No.: 00-06-276R The Honorable Bobby J. Mitchell Mayor, City of L~vtsville PD. Box 299002 Lu--wisville, TX 75029-9002 Communivy: City of Lcwisvillc, Texas Communky No.: 480195 Dear Mayor Mitchell: This responds to a ~luest that the Federal Eln~a'g~ncy Managcm, rg Agency OrEMA) co_mmcnt on the cffcclz~ that a proposed project would have on lira effective Flood Insurance Ra~ Map (FIKM) and Flc<xi Insurance Study OHS) report for Denton County, Texes, alld Imcerporated Areas (the effective FIRI~ arid FI$ report for your commuzfity), in aocordance with Part 65 of the National Flood Insurance Program (NFIP) regulations. In a letter dated September 24, 1999, Mr. Waiter E. Skipwith. P.E.. Vico President, Halff Associates, Inc., requ~,sl~d that FEMA ~wluate the dfec~s ~ proposed placement of fill mid proposed excavation Of a pond and swala along Denton Creek would have on the flood hazard information shown on the ~ve I-II</VI and ElS report, Thc proposed sitg improvements arc ss$oclatcd with the Windsor Estates and DeForeSt Court subdivisions, This request also included more d~tailed topographic information to reflect ead~ing watershed conditionS along Denton Creek from approximately 4,600 feet downstream o£ DePore~ Road (ex,elided) to approximately 1,620 f~et downstream of the convergence of Old Denton Creek. All data ~luimd to complem our review of this t~lUe.st for a Conditional L~e~r of Map Revision (CLOMR) were submitted with letters r,~.'.l Mr. Kermeth M. Griffin, P.E., DirecXor of Public Wcrrks, City of Coppcll; l~.r.T.S. Kumar, P.E., Assistant City l'~ngineer, City of LewisviHe; Ms, Nancy $. Cline, piE., Assistant Director of Public Works, Cily of Carrollton; Mr_ Russell P. Ersklne, Hydrologist, Halff Associates, Inc_; and Mr. Sidpwith_ Because this r~vision rexlucst also affec~ the Cities of Coppell and Cairollton, separate CLOM:Rs for those communities were issued on the same date as this CLOMR. We reviewed the submitb:xi data and the data nsexl to prepare the ~ive F~ ~ dem~in~ that the pm~ ~O~ m~ ~e m~im~ fl~pl~ m~cnt erisa of ~ ~. '~c submit~ ~ ~dve ~C-2 hyd~lic com~r model, dared S~t~ 12, l~, h~ on u~ted to~phic ~ien. ~s W ~e h~ic m~eli~ for ~nWn ~ ~d ~e a~iti~ ora spl~flow ~alysis at Dall~ ~ Club Roa~ wm ~ m ~e ~ go~ifions m~l M o~ re~ of the proposal condi6ons m~el for ~is CLO~ r~est, We beli~e ~ · ~e pr0po~ project is ~ns~cted ~ sho~ on the mhmi~ ~aphlc wo~ m~ ~gtl~ "Revis~ (Pro~d) Condi6ons Site PI~, Windsor ~t~ / ~o~ C~" pmp~ed by ~Ass~iaes, ~c., ~d S~r 1999, ~d &e ~ listed ~low ~ ~iv~ a rev~ion to ~e F~ would ~ ~t~. As a result of the updated topographic information, corrections to the hydreldic modeling for Denton Creek, and addition ora split-flow analysis a~ Dallas Gun Club Road, the elevationS of the flood havhlg a 1-per,eat chazzcc of bcfiag equaled or excem:lcd in any given yom' (base flood) increasccl and decreased colnpared to 03/15/00 15:45 FAX 214 739 0095 HALFF ASSOCIATES {~011/013 the egF~iv~ basra flood el~vaiions (BFEs) for D~nton Creek from approximately 4,600 feet downstream of DeForest Road (extended) to approximately 5,800 fmet upslr~am of the conver~nce of'Old Denton Creek. The maximum inereas~ in BFE, 0,9 foot, occorred approximately $$0 feet downstream of thc convergence of Old Denton Creek. The maximum decrease in BFE. 2.4 feet. occurred approximately 4,600 feet downstream of DeForest Road (extended). The BFEs will dacrease compared to the correcl~t effective BFEs as a result ofihe proposed placement of fill and excavation ora pond and swale along Denton Cr~k. The maximum decrease in BFE, 0.1 loot, will occur approximately 1,140 feet upstream of DeForest Road (extended). As a result o£the updated topographic information, corrections to the cffeciive model, and proposed project, thc BFEs will increase and decrease compared to the eff~tive BFEs for th~ revised roach of Denton Creek. The maximum increase in BFE, 0.9 foot, will occur appmximai¢ly gg0 feet downslream of the convergence of Old Denton Creek. The widths of the Spin:iai Flood Hazard Area (SFHA), thc area thai would be inundated by the base flood, and file regulatory floodway will increase in some a~as and decrease in other areas compared to the effegtive St~.A and floodway widths, Upon completion of the project, your community may submit the data liste~l below and request that we make a final determination on ~vising the effective FIRM and ~lS reporC ,Effective March 1, 1999, FEMA revised the fe~ schedule for reviewing and processing requests for conditional a~d ~A1 modificaiions to published flood information and maps. In accordance with fl~i~ s~hed~de, file fee for your map revision r~quest will be.$3,400 and must be received before we eau begin peoeessing your request. Payment of this fee shall be made in the form of a check or money order, made payable in U,$, funds to the _National Flood Insurance Program, or by credit card. The payment must be forwarded to the following adch~ss: Federal Em c~-ge~,cy Managemea~ Agency Fee-Collection System AdminL~b~tor P.O. Box ~ 173 Marrifield, VA ~211~-3173 · As-built pla~s, certified by a registered professional engineer, of all proposed project elements · Community acknowledgment of the map revision request Certification that all fill placed in the currently effective base floodplain and below the proposed BFE is compacted to 95 pereent of the maximum deesky obtainable with the Standard PrOcwr Test method issued by the American Society for Testing and Materials (ASTM Standard D-698) or an acceptable equivalent method for all areas to be removed from the base floodplain A copy o~.r the public notice dis~buted by your community stating its intent to revise file regulatory floodway, or a smte,~ent by your community that it has notified all affected property owners and affeeted adjacent jurisdictions · A lcucr stating that your community will adopt and enforce the modified regulatory floodway __ 03/15/00 15:45 FAX 214 739 0095 HALFF ASSOCIATES ~012/~13 -- 3 Hydraulic analyses, for a~-Imilt conditions, of the base flood; the floods having a 10-, 2-, and 0.2-1~rennt chance of being equaled or ex~e~ded in any given ~ and regulatory floodway if tho)' differ from th~ proposed conditions models Our review mvealod ~ tl~ revised BFEa and ~1~ fl~ will tic into ~e effective BF~ ~d fl~way wi~in 0.5 ~ at C~ S~ion 2/1870 in ~e sub~d h~nlic m~el for ~nten C~ T~ ~vc-m~nc~ m~hic work ~p includzs only cross ~ons- up w ~d ~clu~g Cross S~ion 22370. PI~ ex.ed ~e fl~pinin ~d fl~w~ ~ &lindens sh~ ~ ~ ~hic ~ ~ ~ ~cl~ ~e ~o~ ~ions ~¢~ C~ss S~6ons ~370 ~d 28870 to ~o~m how ~e ~i~ fl~plain ~d fl~y ~ del~tio~ ~e into ~e a~ve fl~p~n ~d ~w~ ~ do~Oo~ ~ ~e ~ ~d of ~ ~od r~ch along ~nt~ Cr~L Our review of the submitted proposed floodway model r~eal~l that the model ends at Cross ,~ctlon22370. Please ex'mad the vi-0posed floodway model to include effective Cross Sections 23800 tire,ugh 28870, go that the floodway mod~[ is consistent with the multiple profile model and so that the revised BFEs tie into the ,~ffggtivc BFF~ within 0.5 foot, Please ensure that thc floodway ~nalysis produces maxinurm surcharges of no more than 1.0 foot throughout the revised roach. A~er receiving aplnopzlam documentation to show that the project has ~ completed, FEMA will initiate a reviaion to the FIRM and FIS tegofl, Becaus~ the BFEs would ohange ss a resuk of~e project, a 90-day appeal period would be initiated, during which community officials a~d in~t~sted persons may appeal thc revised BlUEs based on scientific or lechnical data. The basis of this CLOMB. is, in whole or in part, a chann=l-modificafiun proj~:t. NFIP regulations, a~ cited in Paragraph 60.3(bXT), rgqulm that communities assure that the..floo?c, artying capacity within the al~rt-d or relocated poniun of any waterco~se is maintained. This pmv~aco Is incorporated into your community's existing floodplain management regulations. Consequently, the ultimate responsibility for mair~enance of ;he modified channel rests with your community. This CLOMR is based on minimUm floodplain management crit~a established under the NFIP. Your community is r~sponsibl¢ for approving all floodplain developm~m and for ensuring all necessary l~tmits required by Federal or St_~r~. law have b~n r~ceiv=d. Stal~, county, and community officials, based on knowledg= of local conditions and in the im~tust of safety, may s~t higher standards for cousU-u~tion in the SFHA. Lf abe $ia~, county, or community has edoptngl more r~sWictive or comprehensive floodplain management crlt~ria, these criteria ~ake precedence over the minimum lqFIP cri~ria. If you have any questions regarding floodplain management regulations for your community or the NFIP in general, please con~t ~he Consultation Coordination Officer (CCO) for your community, Inf0mlation 03/15/00 18:46 FAX 214 739 0095 HALFF ASSOCIATES ~]013/013 4 on the CCO for your eo,~unhy may be obta/ned by contacting the Din~Wr, Mitigation Division of FI/MA in Demvn, Texas, at (940) 89g-5127. If you hay= any q-ucstions~gardlng this CLOMR, plea.~ contact thc FF, MA Map Assistance Cenl*r, toll flee, at I-$77-FI/MA MAP (1-S'77-336-2627). Hazards Study Mitigation Dire~orate Enelosur~ cc: ~e H~bi~ Milb-~ ~vl~ Mayor, Ci~ of ~llwn ~e Hono~ble Ma~, Ci~ of ~11 ~. T- S- ~m~, P-E Ci~ of ~wisville H~ff Ass~, ~. R~I P. H~ ~, Inc. MaY. hew B. Miller, P.E., Chief Hazards Study ~ranch Mitigation Directorate ,~,,,.~©~ ;~TA a.:S/u FOre,F-SS CO.JRT LOMR IV. Photographs Photographs on pages IV-1 through IV-3 illustrate existing conditions at the Windsor Estates/Deforest Court site. Itc, fr' fy ~•wr x, J ' Jew VP, ' i V 1l 1 ; 5� .sue. i 1 �r'sr r .y �P � 1h 6 pAT s , !„ --,,, I� r i [ -.r rr "" fit is +``k c:�s,. r+r.! 1a` ' .:i+m. r 4 - , to f, W - �-., ' it; hake i' ` Al ti ti Lookin: downstream alon' the swale at Section 12, Windsor Estates F r sip' • Looking upstream along the swale at Section 12,Win dso r Estates V. Appendices -- tlALI 1: ASSO( L¥1'I;;S, INC 12 Appendix A Cross-Sections (Corrected Existing Condition) (~) uoge^el~ (~) uo!le^el~ (~) uo!~e^~13 o o o (lJ) UO!leAgl3 (1~) uo!l~^Ol~ ~oe~ (~) uo!:le^al3 (~) uo!le^at'n (~) uo!1~^~13 (~) uo!le^al=~ Appendix A Cross-Sections (Post-Project Condition) (g) UO!l~^OI3 (~t) uo!.le^el'~ ~z ~ (~) uo~eAe13 oO a-o · _- ' ' ' ~ ' ' ' A .... ~6 .... ~ ' ' J~ .... (Ii) UO!l~^Ol3 Appendix B FIS Duplicate Effective Multi-Profile HEC-2 Model: forest.dat 3030,§ 3160.0 3850 Appendix C FIS Duplicate Effective Floodway HEC-2 Model: 4rstfwy.dat Appendix D Corrected Effective Multi-Profile HEC-2 Model: rvexd4st.dat .O55 Appendix E Corrected Effective Floodway HEC-2 Model: rvxfdwy.dat 21545.000 20600+00 455.2B .00 .o0 ~oo 32o.51 Appendix F Revised (Post-Project) Multi-Profile HEC-2 Model: 7669remk.dat 15200.0 1055.4 16582.4 562.2 1302.1 7~43.6 711.0 Appendix G Revised (Post-Project) Floodway HEC-2 Model: 7669fwyk.dat .04 Appendix H Digital HEC-2 Input Data Files on Disk