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ST9301A-SY 940630 Request For Conditional Letter of Map Revision The Elm Fork of the Trinity Rivcr - Sandy Lake Road Bridge Hydraulic Study In the Cities~ of Carrollton, Coppell and Dallas, Texas Prepared for: Dallas County, Texas By: Halff Associates, Inc. 8616 Northwest Plaza Drive Dallas, Texas 75225 This documem is for permitting purposes only and is not intended for Bidding or Construction. ~' /^VO 12687 June 1994 I I June, 1994 Federal Emergency Management Agency 1725 I. Street N. I Washington, DC 20472 i Attn: Mr. Alan Johnson Re: Request for Conditional Letter of Map Revision on the Elm Fork of the i Trinity River in the Cities of Carrollton, Coppell and Dallas, Texas Sandy Lake Road Bridge Hydraulic Study I Dear Mr. Johnson: Enclosed you will fred a technical report on proposed improvements to Sandy Lake Road on the I Elm Fork - Trinity River. This report, prepared by Halff Associates, Inc. for Dallas County Public Works Department, contains the technical data required for issuance of a Conditional Letter of Map Revision. An analysis of fully developed watershed conditions is also included I as required by the City of Coppell's Flood Plain Ordinance No. 87390, City of Carrollton's Flood Plain Ordinance No. 1964, and City of Dallas Flood Plain Ordinance No. 19686. Hard copies of the required HEC-2 hydraulic models, a diskette containing input data fries, and flood plain I and floodway mapping can be found in Appendices A through J. Application/Certification Forms are included in Section II. I The base hydraulic models utilized for this study are as approved by FEMA for the City of Carrollton preliminary FIS update maps published May 27, 1993. The preliminary FIS model was obtained through the FEMA Project Library and verified through Dewberry and Davis I Consulting Engineers for this FIS update. This flood control project is sponsored by Dallas County and the Cities of Dallas, Carrollton, and Coppell for the public benefit, therefore no review fee is included as specified in Section 72.5 of the FEMA regulations. If you have any technical questions on this please contact Dallas County's technical consultant, Ms. Jean report, Hansen, Halff Associates, Inc. (214-739-0094). Administrative questions should be directed to Mr. Ben Cemosek, P.E. at the City of Dallas (214-948-4688). Thank you for your consideration of this request. Yours very truly, I CITY OF DALLAS I Mrs. Jill Jordan, P.E Interim Director of Public Works I Enclosure cc: Mr. Jack Quarles, FEMA Region VI I Ms. Jean I-Iansen, Halff Associates, Inc. Mr. Bill Jessup, Dallas County Public Works I Table 1 Elm Fork - Trinity River Discharge Comparison @ Sandy Lake Road Model/Frequency EF-CDC Reconn Feasibility Study 100-Year 55000 cfs 55200 cfs SPF 100000 cfs 93200 cfs Table 2 Elm Fork - Trinity River Water Surface Elevation Comparison EF-CDC~ Eeasibility Study Halff AssociatesProposed Sandy ' 19942 Revised Base3 Lake4 · lOO_Yr I SPF lO0-Yr I' SPF 1-00-Yr I SPF 100-Yr [ SPF @ Carrollt0n 445.6 450.5 446.0 449.7 446.3 ~ 451.0 445.5 450.6 Dam u/s Sandy Lake 445.9 450.6 447.0 449.8 446.9 451.6 445.9 451.2 Road The Fort Worth District Corps of Engineers Reconnaissance Study hydraulic model - utilized as the base model for the Sandy Lake Road hydraulic study. The preliminary (May 1994) COE Feasibility Study hydraulic model utilizing 1991 topographic data. Halff Associates revised base hydraulic model utilizing EF-CDC as a base model with cross sections from the 1991 Feasibility Study topographic mapping. Halff Associates revised base model with proposed Sandy Lake Road. Halff Associates, Inc. November, 1994 Sandy Lake Rd~Elm Fork Hydraulic Study I HALFF ASSOCIATES, INC. ENGINEERS · SCIENTISTS · SURVEYORS I)AI.I.AS · FORTWOt~T}[ · ARLINGTON · CItlCAGO 8616 NORTHWEST PLAZA DRIVE · DALLAS, TEXAS 75225 214/739 -0094 · FAX 214/739-0095 November 1, 1994 AVO 12687 City of Dallas Public Works and Transportation 320 E. Jefferson, Room 321 Dallas, Texas 75203 Attn: Sophia Iliadou, P.E. Re: Sandy Lake Road/Elm Fork Hydraulic Study Dear Sophia: ~ As discussed in our October 27th meeting, the 100-year discharges and water surface elevations computed by the COE for the Upper Trinity Feasibility Study are within 0.5 feet of those computed in the above referenced study for improvements to Sandy Lake Road. The computed water surface elevations for the Standard Project Flood are higher in the Sandy Lake Road study primarily because of the higher Reconnaissance Study discharges (ie, the Sandy Lake Road study is more conservative). These comparisons, including the computed water surface elevations for proposed Sandy Lake Road are shown in the attached tables. Please do not hesitate to call if we can provide any additional data. Thank you for your help to expedite the FEMA CLOMR and COE CDC submittals for this project. Sincerely, HALFF ASSOCIATES, INC. an Hansen, P.E. c: Charles Gojer, P.E., Gojer and Associates, Inc. Bill Jessup, P.E., Dallas County Public Works Attachment TRANSPORTATION · WATER RESOURCES LAND DEVELOPMENT · MUNICIPAL · ENVIRONMENTAL · STRUCTURAL SURVEYING GLOBAL POSITIONING SYSTEM (G PS )· REMOTE SENSING AND MAPPING LANDSCAPE ARCHITECTURE · PLANNING SANDY LAKE ROAD HYDRAULIC STUDY TABLE OF CONTENTS Page # I. Introduction I- 1 II. Application/Certification Forms with Attachments Form 1 - Revision Requestor and Community Official Form II-1 Attachment lA - Proposed Encroachments II-6 Form 2 - Certification by Registered Professional Engineer II-7 Form 4 - Riverine Hydraulic Analysis Form II-8 Attachment 4A - Summary of Hydraulic Models II-13 Attachment 4B - Analysis of 'n' values II-18 Photographs II-20 Form 5 - Riverine/Coastal Mapping Form II-28 Attachment 5A - Revised flood plain and floodway boundaries II-31 Form 6 - Channelization Form II-32 -- Form 7 - Bridge/Culvert Form II-35 -- APPENDICES _ Appendix A. Figures Appendix B. Revision Request Acknowledgemcms City of Carrollton City of Coppell _ Appendix C. Geotechnical Report Appendix D. FIS Exist. Conditions (multi-profile) Hee-2 Model (Replication - SHELREV2) Appendix E. FIS Exist. Conditions Floodway Hec-2 Model (Replication - SHFDWY-2) -- Appendix F. Corrected Exist. Conditions (multi-profile) Hec-2 Model (REVBASE) Appendix G. Corrected Exist. Conditions Floodway Hec-2 Model (RVEXFDW2) Appendix H. Proposed Conditions (multi-profile) Hec-2 Model (SI-IEI~PRO) -- Appendix I. Proposed Conditions Floodway Hec-2 Model (PROPFDWY) Appendix J. HEC-2 Input Data Files LIST OF TABLES Table 4A-1 High Water Data - 1989 & 1990 Floods I1-14 - Table 4A-2 Comp .arison of Recorded vs. Computed Water Surface Elevations 11-15 Table 4A-3 Flow Distribution - 100 -year Flood 11-16 Table 4A-4 Manning's 'n' Value Comparison 11-18 - Table 4A-5 FEMA Form 4 - Water Surface Elevation (WSFJ~) Check 11-22 Table 4A-6 Duplicate vs. Corrected Effective Water Surface Elevations 11-24 Table 4A-7 Comparison of WSEL's and Velocities - Existing Landuse Discharges 11-25 -- Table 4A-8 Comparison of 100-year WSEL's - Fully Developed Landuse Discharges 11-26 Table 4A-9 Comparison of SPF WSEL's - Fully Developed Land use 11-27 LIST OF FIGURES IN APPENDIX A Figure 1 Location Map Figure 2 1994 Revised Base vs. 1991 FIS Cross Sections 2A Section 88160 (88150) 2G Section 93710 (93670) _ 2B Section 89230 (89050) 2H Section 93750 (93730) 2C Section 90210 (90000) 2I Section 93840 (93810) 2D Section 91050 (90880) 2J Section 97710 (97570) _ 2E Section 92050 (92090) 2K Section 98460 (98450) 2F Section 93660 (93620) 2L Section 99420 (99280) _ Figure 3 Flood Plain Information - Revised Base (Corrected Effective) Figure 4 Proposed Flood Plain and Floodway Figure 5 Revised Base vs. Proposed Condition Cross Sections - Figure 6 Proposed Condition Prof'fle Figure 7 FEMA FIRM Maps - 7A City of Carrollton FIRM (preliminary) dated 4-92 7B City of Carrollton FIRM (preliminary) dated 5-93 7C City of Coppell FIRM dated 4-94 - 7D City of Dallas FIRM dated 7-91 Figure 8 Plan View and Cross Section of Proposed Sandy Lake Road Bridge - I. Introduction REQUEST FOR CONDITIONAL LETTER OF MAP REVISION ELM FORK - TRINITY RIVER SANDY LAKE ROAD BRIDGE HYDRAULIC STUDY - I. Introduction This study was undertaken to provide the necessary technical data for issuance of a FEIMA - Conditional Letter of Map Revision (CLOMR) for proposed improvements to Sandy Lake Road from IH 35E to MacArthur Boulevard in the cities of Carrollton, Coppell and Dallas, Texas. This roadway is a major thoroughfare from IH 35 into the City of Coppell. The existing street is two lane blacktop - and frequently closed due to flooding. The proposed improvements were approved as part of the 1992 Dallas County Bond Program. Halff Associates, Inc., has been retained by Dallas County for hydraulic design of the proposed bridge structure including any downstream compensating excavation. The Elm Fork of the Trinity River flows in a southerly direction from its headwaters north of Lewisville, Texas to its confluence with the West Fork at the Trinity River floodway at the Irving/Dallas city limits. The proposed improvements are located in the reach from north of Belt Line Road through Sandy Lake Road, approximately 16 river miles upstream. In this reach the Elm Fork forms the corporate boundary between the cities of Carrollton and Coppell. In addition, the area at the Sandy Lake Road crossing of the Elm Fork from the Carrollton Dam upstream approximately 1500 feet (see Figure 1) is owned by and within the City limits of Dallas. Dallas Water Utilities diverts raw water in this area _ to the Elm Fork Treatment Plant for public water supply. The Carrollton Dam is owned and operated by the City of Dallas. _ Approximately 5000 feet of the existing Sandy Lake Road embankment would be inundated by the 100 year frequency event. Several sections of roadway are also overtopped for lower frequency events such as the 10-year flood. The proposed improvements will remove Sandy Lake Road from the _ 100-year flood plain with minimum of one (1) foot of freeboard to the top of curb in the overbank areas. The proposed 1040 foot long bridge will span the main channel and mediate left overbank area with two (2) foot of freeboard to the minimum low beam elevation. Downstream of the bridge structure _ a swale/pond is proposed to mitigate the effects of raising the overbank embankment. The pond and downstream excavation is in the grassland areas of Mclnnish Park which is owned and operated by the City of Carrollton Parks Deparmaent. No modifications are proposed for the Elm Fork channel. The proposed improvements will alleviate street flooding on this major thoroughfare in both the cities of Carrollton and Coppell. Potential increases in water surface elevation and loss of valley of -. storage due to the road embankment are compensated for with downstream excavation within an existing park. The majority of the downstream improvements (swale/pond) are within the City of Carrollton. However, the bridge itself is in the City of Dallas. Therefore, Dallas is sponsoring the project as Flood - Plain Administrator. Letters are provided from the cities of Coppell and Carrollton indicating their support of the project (see Appendix B). Public notification will be submitted upon completion of construction and submittal for a Final Letter of Map Revision. -- I-1 During the late 1970's and early 1980's numerous reclamation projects were consu'ucted - in the Trinity River flood plain including several projects along the Elm Fork. Hydraulic modelling was prepared for each individual project, however, an analysis of the cumulative effects of the many reclamation projects was needed throughout the watershed. In 1984 the Fort -- Worth District, U.S. Army Corps .of Engineers (COE) began preparation of a Regional Environmental Impact Statement (REIS) to address the cumulative impacts of development within the Trinity River flood plains in the Dallas - Fort Worth metroplex. This study utilized existing - hydraulic models, looking at existing fills/encroachments and future development scenarios within the watershed. One of the conclusions was that intense flood plain development upslxeam could imperil the Dallas levees. Recognizing the need for a comprehensive plan the Senate Committee - on Environment and Public Works authorized an 18-month Reconnaissance Study on the Upper Trinity River corridor. This study has been completed and the COE has now preceded to the Feasibility Study phase which includes the preparation of new hydrologic and hydraulic - modelling based on updated topography for the entire Trinity River corridor within the Dallas - Ft. Worth metroplex. Aerial Mapping for this effort was performed in February 1991. The new aerial mapping is utilized in this "Sandy Lake Road Bridge Hydraulic Study". One of the results of the Trinity River REIS was the joint adoption of a common permit process and criteria known as the Corridor Development Certificate (CDC). This project will require a Corridor Development Certificate (CDC) permit. This is a cooperative flood plain management program developed as a response to the Corps of Engineers (COE), Fort Worth District, Final Regional Environmental Impact Statement (REIS) for the Trinity River. The CDC permit process has been adopted by most of the communities along the Trinity corridor including the cities of Can'ollton, Coppell and Dallas. The proposed improvements comply with the CDC Common Permit Criteria and are being submitted to the COE and adjacent municipalities for review in conjunction with this submittal for a Conditional Letter of Map Revision. _ The required forms for this "Request for Conditional Letter of Map Revision" are included in Section II of this report. The November 1992 forms are utilized for this submittal, as approved by the FEMA review consultant, Michael Baker, Jr., Consulting Engineers. Additional _ information is provided on Attachments to these forms. - I-2 _ II. Application/Certification Forms with Attachments ~ ~ FEMA USE ONLY -- FORM 1 REVISION REQUESTOR AND COMMUNITY OFFICIAL FORM 1. The basis for this revision request is (are): (check all that apply) [] Physical change [] Existing - [] Proposed r2 Improved methodology [] Improved data -- [] Hoodway revision [] Other _ Explain 2. Flooding Source: Elm Fork of the Trinity River 3. Project Name/Identifien Sandy Lake Road at Elm Fork, Trinity River 4. FEMA zone designations affected: Zones AE and X (example: A,AI-I,AO,A1-A30~9,AE,V,V 1-V30,VE,B,C,D,X) 5. The NFIP map panel(s) affected for all impacted communities is (are): Community Community Map Panel Effective - No. Name County State No. No. Date 480167 Carrollton,City Dallas TX 480167 0010E 04/17/92' 480167 Carrollton,City Dalla~ TX 480167 0015E 05/'27/93* -- 480171 Dallas, City Dallas TX 480171 0020D 07/02/91 480170 Col~vell, City Dallas TX 480170 0010E 04115/94 * Preliminary 6. The submitted request encompasses the following types of flooding, slructures, and associated disciplines: (check all that apply) Types of Flooding Structures Disciplines' [] Riverine [] Channelization [] Water Resources [] Coastal [] LeveedFloodwall [] Hydrology [] Alluvial Fan [] Bridge/Culvert [] Hydraulics [] Shallow Flooding [] Dam [] Sediment Transport [] Lakes [] Coastal [] Interior Drainage Affected by [] Fill (Embankment) [] Structural wind/wave action [] Pump Station [] Geotechnical _ [] Yes [] None [] Land Surveying [] No [] Other (describe) [] Other (describe) [] Other (describe) Compensating Excavation * Attach completed "Certification by Registered Professional and/or Land Surveyor" Form for each discipline checked. (Form 2) October 1992 Page 1 of 5 - II-1 APPt,ICATION/CERTIFICATION ~ FOR. CONDmONAL I.J~l-l'{:!l~ OF MAP ~ISION. LIt'ri'ER OF MAP RI~/i$1ON ,AN]) P'rTYSICAL MAP REVISION REVISION REQUESTOR AND COMMUNITY OFFICIAL FORM Floodway Information · Does the affected flooding source have a floodway designated on the effective FIRM or FBFM? ~ Yes [] No · Does the revised floodway delineation differ from that_ shown on the effective FIRM or FBFM? [] Yes [] No If yes, give reason: Revised data and £fll for proposed road; proposed floodway set at effective flow limits downstream of Sandy Lake Road. Attach request to revise the floodway from community CEO or designated official Conditional CLOMR Attach copy of either a public notice distributed by the community stating the community's intent to revise the floodway or a statement by the community that it has notified all affected property owners and affected adjacent jurisdictions. N/A Conditional LOMR Requested Does the State have jurisdiction over the floodway or it's 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. Proposed Encroachments With floodways: IA. Does the revision request involve fill, new construction, substantial improvement, or other development in the floodway? [] Yes [] No lB. If yes, does the development cause the 100-year water surface elevation increase at any location by more than 0.000 feet? Max increase 0.03 feet [] Yes [] No (See Attachment IA and Table 4A-7) Without floodways: (not applicable) 2A. Does the revision request involve fill, new construction, substantial improvement, or other development in the 100-year flood plain? [] Yes [] No 2B. If yes, does the cumulative effect of all development that has eccunexl since the effective SFHA was originally identified cause the 100-year water surface elevation increase at any location by more than one foot (or other surcharge limit ff community or state has adopted more sUingent criteria)? [] Yes [] No If answer to either Items lB or 2B is yes, please provide documentation that all requirements of Section 65.12 of the NFIP reg. lations have been met. Revision Requestor Acknowledgement · Having read NFIP Regulations, 44 CFR Ch. I, parts 59, 60, 61, 65, and 72, I believe that the proposed revision [] is [] is not in compliance with the requirements of the aforementioned NFIP Reg~jl_afions. Community Official Acknowledgement · Was the revision request reviewed by the community for compliance with the community's adopted flood plain management ordinances? [] Yes [] No · Does this revision request have the endorsement of the community? [] Yes [] No If no to either of the above questions, please explain: Please note that community acknowledgement and/or notification is required for all requests as outlined in Section 65A (b) of the NFIP Regulations. November 1992 Page 2 of 5 II-2 APPLICATION/CI~.T~ICATION FORMS FOR CONDITIONAL LIa-i'i-KR OF ~ REVISION, Lk~l-l'kiR OF }dA~ REVISION AND PHYSICAL MAP REVISION - REVISION REQUESTOR AND COMMUNITY OFFICIAL FORM Operation and Maintenance · Does the physical change involve a flood control structure (e.g., levees, floodwolig, channelization, basins, dams)? [] Yes [] No Relief swale/compensating excavation. No channel work, no modification to existing structures - except for construction of a new bridge. If yes, please provide the following infonnation for each of the new flood control structures: _ Swale within the City of Carrollton 'Mclnnish Park' A. Inspection of the flood conlxol project will be conducted periodically by City of Carrollton (~naty) -- Parks Department with a maximum interval of 12 months between inspections. B. Based on the results of scheduled periodic inspections, appropriate maintenance of the flood control facilities will be conducted by the City of Carrollton Parks Department -to ensure the integrity and degree of flood protection of the s_tmctum. -- C. A formal plan of operation, including documentation of the flood warning system, specific actions and assignments of responsibility by individual name or rifle, and provisions for testing the plan at intervals not less than one year, [] has [] has not been prepared for the flood control structure. Conditional Letter of Map Revision D. The community is willing to assume responsibility for [] performing [] overseeing compliance with the maintenance and operation plans of the City of Can'ollton Parks -- Department 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. Attach operation and maintenance plans NIA Requested Response from FEMA . · After examining the pertinent NFIP regulations and reviewing the document entitled "Appeals, _ Revisions, and Amendments to Flood Insurance Maps: A Guide for Community Officials," dated January 1990, this request is for a: X a. CLOMR A letter from FEMA commenting on whether a proposed project, if built as - proposed, would justify a map revision (LOMR or PMR), or proposed hydrology changes (see 44 CFR Chi., Parts 60,' 65 and 72). - .~b. LOMR A letter from FEMA officially revising the current NFIP map to show changes to flood plains, floodways, or flood elevations. LOMR's typically depict decreased flood baTards. (See 44 CFR Ch. I, Parts 60 and 65). __c. PMR A reprinted NFIP map incorporating changes to flood plains, floodways, or flood elevations. Because of the time and cost involved to change, reprint, and redistribute an NFIP map, a PMR is usually processed when a revision reflects - increased flood baTarcls or large-scope changes. (See 44 CFR Ch. I, Parts 60 and 65). -- ~d. Other: Describe - October 1992 Page 3 of 5 11-3 APPLICATION/CERTI~CATION FORMS FOR CONDITIONAL LI~i'i~R OF i~ REVISION, I..~l-I'kl~ O~' ~ REVISION AND PHYSICAL MAP REVISION ? REVISION REQUESTOR AND COMMUNITY OFFICIAL FORM Forms Included Form 2 entitled "Certification By Registered Professional Engineer And/Or Land Surveyor~ must be submitted. The following forms should be included with this request if (check the included f~ns): · Hydrologic analysis for riverine flooding differs from that [] Hydrologic Analysis Form used to develop FIRM (Form 3) · Hydraulic analysis for riverine flooding differs from that [] Riverine Hydraulic Analysis used to develop FIRM (Form 4) · This request is based solely on ulxlated topographic [] Riverine/Coastal Mapping information (Form 5) · The request involves any type of channel modification [] Channelization (Form 6) · The request involves new bridge or culvert or revised [] BridgedCulvert Form analysis of an existing bridge or culvert (Form 7) · The request involves a new or revised levee/floodwall [] LeveedFloodwall System system Analysis (Form 8) · The request involves analysis of coaslal flooding [] Coastal Analysis Form (Form 9) · The request involves coastal structures credited as providing [] Coastal Structures Form protection from the 100-year flood (Form 10) · The request involves an existing, proposed, or [] Dam Form (Fc~'m 11) modified dam · This request involves structures credited as providing [] Alluvial Fan Flooding Form protection from the 100-year flood on an alluvial fan (Form 12) Initial Review Fee · The minimum initial review fee for the appropriate request category has been included. [] Yes [] No If yes, the amount submitted is $ · This request is for a project that is for public benefit and is intended to reduce the flood hazard to existing development in identified flood bnTa_rd areas as opposed to planned flood plain development. [] Yes [] No November 1992 Page 4 of 5 11-4 APPLICATION/CI~RT~I~TION FORM~ FOR CONDmONAL Lgrr~ oF ~ mtvmoN, Lm-r~m OF MAP RltVI~ION AND ivrIYSlCAL MAP RBVISION REVISION REQUESTOR AND COMMUNITY OFFICIAL FORM Note: I understand that my signature indicates Note: Signature indicates that the community -- that all information submitted in support of understands, from the revision requestor, the impacts this request is correct, to the best of of the revision on flooding conditions in the community. my knowledge and belief. Signature of Revision Requestor Signature of Community Official Mr. Allen Bud Beene, P.E., Director of Public Works Mrs. Jill Jordan, P.E., Interim Director ofpublic Works Printed Name and Title of Revision Requestor Printed Name and Title of Community Official D~_.ila.q County~ Texas City of Dalla~ Texas * _ Company Name Community Name Date: Date: * Request for Conditional LOMR. Letters from the cities of Coppell and Carrollton, Texas are included in Appendix B. Additional notifications will be handled through the Corridor Development Certificate Process (see Section I) and provided as part of the post- construction sUbmittal for a Final LOMR. Attach letters from all affected jurisdictions acknowledging revision request and approving changes to floodway, if applicable. _ Note: Although a photograph of physical changes is not required, it may be helpful for FEMA's review. See Attachment 4B for photographs of existing conditions. October 1992 Page 5 of 5 -- 11-5 AI~PLICAT1ON/CERTINICATION FORMS FOR CONDITIONAL Ll~-i-il:il~ OF ~ REVISION. L~-~t OF MAP REVISION AND PHYSICAL MAP RBVISION FORM 1 - REVISION REQUESTOR AND COMMUNITY OffICIAL ATTACHMENT lA - PROPOSED ENCROACHMENTS The proposed improvements to Sandy Lake Road will provide significant benefits to the citizens of the cities of Carrollton and Coppell by relieving flooding of this major thoroughfare from 1I-I 35. Flood plain management ordinances for both cities require that all projects receive conditional approval from FEMA prior to construction and show proof by hydraulic analysis that the project will cause no -- increase in the 100-year water surface elevation for a fully developed watershed. The proposed Sandy Lake Road embankment and downstream excavation causes a 0.03 foot rise -- in 100-year computed water surface elevation at Cross Section 88450 approximately 300 feet upstream of the Belt Line Road crossing. This rise is caused by non-effective flow in the left overbank due to the proposed Sandy Lake Road embankment. Immediately upstream (Section 89230) the water surface -- elevation decreases by 0.11 feet. No additional flooding is caused by this minor rise (<0.05 feet). Both Cities have reviewed and accepted this modelling and support this revision request (see Appendix B). Attachment to Form 1 II-6 June 1994 ~MA USE ONLY -- FORM 2 CERTIFICATION BY REGISTERED PROFESSIONAL ENGINEER AND/OR LAND SURVEYOR · 1. This'certification is in accordance with 44 CFR Ch. I, Section 65.2. 2. I am licensed with an expertise in Civil Engineering -- [example: water resources (hydrology, hydraulics, sediment transtxa't, interior drainage)* structural, geotechnical, land surveying.] -- 3. I have 9 years experience in the expertise listed above. 4. I have [] prepared il reviewed the _a_~l~hed supporting data and analyses related to my expertise. -- 5. I [] have I~ have not visited and physically viewed the project. Proposed Project CLOMR. 6. In my opinion, the following analyses and/or design, were performed in accordance with sound -- engineering practices: Hydraulic Analysis for proposed Sandy Lake Road with downstream overbank compensating excavation. N/A7. Based upon the following review, the modifications in place have been consmacted in general accordance with plans and specifications. -- Basis for above statement: (check all that apply) a. [] Viewed all phases of actual construction. b. tn Compared plans and specifications with as-built survey information. -- c. [] Examined plans and specifications and compared with completed projects. d. [] Other 8. Ail information submitted in support of this request is correct to the best of my knowledge. I -- understand that any false s~atement may be punishable by fine or imprisonment under Title 18 of the United States Code, Section 1001. -- Name: C. Jean Hansen, P.E. (please print or type) Title: Project Manager (please prim or type) -- Registration No. 69365 Expiration Date:Annual renewal 12/94 State Texas Type of License Professional Engineer - / Seal * Specify Subdiscipline Note: Insert not applicable (N/A) when statement does not apply. October 1992 Page 1 of 1 1I-7 APPLICATION/C~RTIPICATION FORMS FOR CONDmONAL LUl 1 ~ OF MAP REVISION, Llal { t~R OF MAP REVISION AND PHYSICAL MAP REVISION - ~ FEMA USE ONLY FORM 4 RIVERINE HYDRAULIC ANALYSIS FORM Community Name: City of Carrollton, Texas Flooding Source: Ehn Fork of Trinity River Project Name/Identifier. Sandy Lake Road at Elm Fork, Trinity River Reach to be Revised Downstream limit Section 88160 Upstream limit Section 99420 Effective FIS [] Not studied [] Studied by approximate methods Downstream limit of study Upstream limit of study [] Studied by detailed me[hods Dowustream limit of study Section 3270 (Irving, Texas) -- Upstream limit of study Section 135000 (Lewisville, Texas) [] Floodway delineated _ Downstream limit of floodway Section 3270 (Irving, Texas) UpsUeam limit of floodway Section 135000 (Lewisville, Texas) Hydraulic Analysis Why is the hydraulic analysis different from that used to develop [he FIRM. (Check all that apply) [] Not studied in FIS [] Improved hydrologic dot_~!analysis. Explain: - ~ Improved hydraulic analysis. Explain: Updated cross sections based on COE "Feasibility Study" more detailed topographic information (flown February, 1991), from cross section 88160 to cross section 99420. [] Flood control su'uctore. Explain: [] Oihez. Explain: Proposed proiect: fill as necessary to raise Sandy Lake Road above the 100-yr flood plain. Compensating excavation included in [he form of a relief swale in [he left overbank. November 1992 Page 1 of 5 _ II-8 APPLICATION/C~RTIFICATION FORMS FOR CONDITIONAL L~i I~ OF MAP RBVISION, L~I-I-I~R OF MAP Pi{VISION A.ND PHYSICAL MAP l~VlSION RIVERINE HYDRAULIC ANALYSIS FORM Models Submitted Full input and output listings along with files on diskette (ff available) for each of the models listed below and a summary of the source of input parameters used in the models must be provided. The summary must include a complete description of any changes made from model to model (e.g. duplicate effective model to corrected effective model). Only the Duplicate Effective and the Revised or Post-Project Conditions models must be submitted. See instructions for directions on when other models may be required. Only the 100-year flood profile is required for SFHAs with a Zone A designation. See Attachment 4A. [] Duplicate Effective Model - From City of Coppell FIS update 4-94 and City Natural . Floodway of Carrollton update Preliminary 4-92 and 5-93. [] [] Copies of the hydraulic analysis used in the effective FIS, referred to as the effective models (10-, 50-, 100-, and 500-year multi-profile runs and the floodway run) must be obtained and then reproduced on the requestor's equipment to produce the duplicate effective model. This is required to assure that the effective model input nato has been transferred ctm~cfly to the requestor's equipment and to assure that the revised data will be integrated into the effective data to provide a continuous Iris model upstream and downstream of the revised reach. Natural Floodway [] Corrected Effective Model [] [] The corrected effective model is the model that ettrects 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 corrected effective model must not reflect any man-made physical changes since the date of the effective model. '~ error could be a technical error in the modeling procedures, or any construction in the flood plain that occurred prior to the date of the effective model but was not incorporated into the effective model. Natural Floodway [] Existing or Pre-Project Conditions Model [] [] The duplicate effective or corrected effective model is modified to produce the existing or pre-project conditions model to reflect any modifications that have occurred within the flood plain 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 or duplicate effective model. Natural Floodway [] Revised or Post-Project Conditions Model [] [] The existing or pre-project conditions model (or duplicate effective or corrected effective model, as appropriate) is revised to reflect revised or post-project conditions. This model must incorporate any physical changes to the flood plain since the effective model was produced as well as the affects of the project. Natural Floodway m Other: Please aUach a sheet describing all other models submitted. See Attachment 4A - Summary of Hydraulic Models for Additional Information. Hard copies of HEC-2 models are included in Appendices D through I. Appendix J contains a diskette with the input data f'des for these models. October 1992 Page 2 of 5 II-9 APPLICATION/CBRT~qCATION FORMS NOR CONDrrlONAL LI~i-t~R OF MAP RI~/ISION. l~r~ OF MAP REVISION AND PHYSICAL MAP RBVISlON - RIVERINE HYDRAULIC ANALYSIS FORM Model Parameters (from model used ~o revise 100-year water surface elevalions) 1. Discharges: Ups~eam Limit Downstream Limit 10-year 24400 24400 50-year 39900 39900 100-year 48600 48600 -- 500-year 91200 91200 ($PF as shown in hydraulic model provided by the FEMA Project Library) Allach diagram showing changes in 100-year discharge -- No change in lO0-year discharge. 2. Explain how ~he starting water surface elevations were determined Slm'dng WSEL's are identical to WSEL's at cross section 85000 in FIS duplicate effective HEC-2 Model. Starting Water Surface Elevation · _* Duplicate model only. 10-year 435.81 Revised in subsequent models. 50-year 438.17 -- See Attactunent 4A 100-year 439.25* (439.28) Floodway 439.28 500-year ~.~.50 3. Give range of friction loss coefficients overbank 0.035 to 0.13 chan 0.03 to 0.075 If friction loss coefficients are different anywhere along the revised reach from those used to develop -- the FIRM, give location, value used in the effective FIS, and revised values and an explanation as to how the revised values were determined. * Cl~nnel 'n' values assigned in thefield -- Location - channel* FIS Revised (Proposed) 88450 thru 90210 0.075 0.0~0 + 0.0~5 _ (cleared channel banks) 93660 thru 93815 0.060 0.030 to 0.055 (concrete dam; clear channel) -- Explain: Base 'n' values from SHRI.REV2 u~lb,~d for starling conditions. Modifications rustic during calibration (see Attachment 4A). Attachment 4B describes the corrected Effective and Proposed Condition 'n' values. 4. Describe how the cross section geometry d_sts were determined (e.g., field survey, topographic map, taken from previous study) and list cross sections that were added. Corrected Effective Cross section geometry supplied by COE from topography flown in Feb. 1991. Cross sections obtained by photogrammetic methods as discussed in _ Attachment 4A. Sandy Lake Road existing bridge at cross sections 93750 and 93780 from ELMREV2 model (effective FIS mod~l) with overbank modifications from 1991 topo. FIS - Model cross section 88150-99280 replaced by cross sections 88160-99420, except at Sandy Lake Rd. November 1992 Page 3 of 5 II-10 APPLICATION/C]~RTIFICATION FORMS FOR CONDITIONAL LI~I-I'I~R OF bdAP REVISION, L~l'l'lfl( OF I~[AP R[~'ISION AND PHYSICAL MAP P,B, VISION RIVERINE HYDRAULIC ANALYSIS HDRM Model Parameters (Cont'd) Explain how reach lengths for channel and overbanks were determin~ The photogrammetric cross section locations were prodded by the C.O.E; reach lengths and revised stationing is from this aerial topography, flown February 1991 (See Attachment 4A and Figure 3t Appendix A). Results (from model used to revise lO0-year water surface elevations) 1. Do thc results indicate: a. Water surface elevations higher fl~an end points of cross sections? [] Yes [] No Sections allowed to extend in non-effective flow areas for duplicate, corrected effective and proposed conditions (See Figure 2 and 5, Appendix A). b. Supererifical depth? [] Yes [] No c. Critical depth? [] Yes [] No d. Other unique situations? [] Yes [] No ff yes to any of the above, attach an expiation that discusses the situation and how it is presented on the profiles, tables and maps. 2. What is the maximum head loss between cross-sections? l~ =l.00ft WSEL~l.37 ft Proposed condition - revised reach (88160-99420) 3. What is the distance between the cross-sections in 2 above? 3820 ft 4. What is the maximum distance between cross-sections? 3820 ft Proposed condition - project reach 5. Floodway determination a. What is the maximum surcharge allowed by the community or State? 1.0 foot b. What is the maximum surcharge for the revised conditions? 0.0 foot within project reach; upstream a 028 foot rise occurs c. What is the maximum velocity?. Average channel velocity 8.8 fps d. What type of erosion protection is provided? Explain: Maximum velocity occurs in natural cross section at the downstream limit of the project. No improvements are proposed in this area. At Sandy Lake Road, concrete side slopes are proposed at the bridge abutments (Average chart, velocities 5.2 to 7.2 fps). Ril>-mp is proposed in the swale area under the new bridge structure (overbank velocities 5.7 to 6.3 fps). Soils are generally clay (see Appendix C). October 1992 Page 4 of 5 TT-11 APPLICATION/CI/R'f~ICATION FORM,~ FOR CONDITIONAL Li/TI'BR OF MAP RI/VISION, L~¥1'Ktt OF MAP RI~rISION AND PHYSICAL MAP RBVlSION - RIVERINE HYD~ULIC ANALYSIS FORM -- Results (Cont'd) 6. Is the discharge value used to determine the floodway anywhere different from that used to -- determine the natural 100-year flood elevations? [] Yes [] No If yes, explain: -- Attach a Floodway Data Table showing data for each cross section listed in the published floodway · data table in the FlS report. See Table 4A-5. -- 7. Do 100-year water surface elevations increase at any location? [] Yes [] No max increase 0.03 foot at Section 88450 _ If yes, please auach a list of the locations where the increases occur, slate whether or not the increases are located on the requestor's property, and provide an explanation of the reason for the increases. -- See Form 1 Attachment lA and Tables 4A-5, 4A-6 and 4A-7. Please attach a completed comparison table entitled: Water Surface Elevation Check- Table 4A-5. Also see Tables 4A-6 and 4A-7. Revised FIRM/FBFM and Flood Prof'fles _ A. The r~vised water surface elevations tie into those computed by the effective FIS Model (10-, 50-, 100-, and 500-year), downslxeam of the project at cross-section 88050 within 110 feet and upstream of the project at cross section 110580 within 11,000 feet. * - B. The revised floodway elevations tie into those computed by the effective FIS model, downstream of the project at cross section 88050 within 110 feet and upstream of the project at cross section 110580 * within 11,000 feet. * This is the last cross section in the current effective FIS models. - Upstream, the City of Lewisville has not been updated. Computed WSEL's are within 0.50 foot at this upstream Study limit for all models. See Tables 4A-5, 4A-6 and 4A-7. C. Attach profiles, at the same vertical and horizontal scale as the profiles in the effective FIS report, showing stream bed and prof'des of all floods studied (without encroachment). Also, label all cross sections, road crossings (including low chord and top-of-road data), culverts, tributaries, corporate limits, and study limits. - See Figure 6, Appendix A _ Proceed to Riverine/Coastal Mappiug Form. November 1992 Page 5 of 5 - II-12 AI~L1C.~TION/f~RT~ICATION FORMS ~ CONDmONAL l.~rrua OF MAP RBVISION, LIfl'iI~R OF MAP RI{VISION ,4~,{D PHYSICAL MAP RI~VISION FORM 4 - RIVERINE HYDRAULIC ANALYSIS ATTACHMENT 4A - SUMMARY OF HYDRAULIC MODELS Duplicate Effective Models (Appendix D and Appendix E): The digital file for the Elm Fork hydraulic model was obtained from Ron Morrison, P.E., the consulting engineer who prepared the City of Copper FIS update. This is the model utilized to update - Coppell's FIRM dated April 15, 1994. Computed water surface elevations (WSEL's) match the FIS update currently in process for the city of Carrollton as provided by the FEMA Project Library. This update is being handled by the FEMA review consultant, Dewberry and Davis, Inc. and was confirmed - by their office. The duplicate floodway model was recreated utilizing the hard copy output provided by the FEMA Project Library. The FIS update floodway model (hard copy) provided by the FEMA Project Library begins at Cross Section 64820 with a starting WSEL's of 433.88 for the natural condition nm and 434.05 for the floodway encroachment run. The multi-profile run (also provided by the Project Library) computes a WSEL of 434.04 at Cross Section 64820. This error is incorporated into the duplicate effective models utilized as a base for the Sandy Lake Road Hydraulic Study. The duplicate effective models were _ shortened to begin at Cross Section 85000, primarily because a digital file was not available for the floodway model. The starting water surface elevation error is reflected in the effective and duplicate effective floodway models as shown on Table 4A-5, Water Surface Elevation Check. The natural (multi- _ prof'fle) condition run does not include this error as shown on Table 4A-6 under Base model. The correct (mulfi-prof'fle) computed water surface elevation is utilized in the Corrected Effective floodway model as discussed below. Corrected Effective Models (Appendix F and Appendix G): _ The corrected effective model incorporates new aerial topography from Cross Section 88160 through Section 99420. This topography was flown in February 1991 for the Upper Trinity River Feasibility Study. The Upper Trinity River Feasibility Study is a projected five-year study and updated - hydrologic and hydraulic modelling for the Elm Fork will not be completed by the COE until late 1994. Since the Feasibility Study is ongoing and the new topography is available, Halff Associates prepared an updated existing condition model in the Sandy Lake Road area. This new hydraulic model is based -- on the best currently available data (1991 aerial topography). Digital Photogrametric cross section data was provided by the Corps of Engineers (COE), Ft. Worth District, along with the "in-house" COE computer program "FINTER", which reduces the number of ground points in each cross section to 100 - or less. The digital cross-section data provided by the COE was reduced in steps by cross section to -- develop hydraulic model cross sections with less than 100 ground points as required by HEC-2. Sandy Lake Road bridge sections and existing "n" values were inserted from the base model (effective) for the Elm Fork. Reach lengths and bank stations were input utilizing the digital files containing section - locations as provided by the COE. The revised base hydraulic model was then calibrated to high water marks from the 1989 and 1990 floods. Other engineering studies were also reviewed for applicable modelling notes or corrections. Attachment to Form 4 II-13 June 1994 The Elm Fork flood plain is partially urbanized through this reach restricting flows through four main passages: two routes within the east overbank, the main channel and the west overbank. -- Noneffective flow areas were modelled by establishing encroachment limits in a revised base model based on a delineation of the 100-year water surface elevation and the standard practice of 4:1 expansion downstream and 1:1 contraction upstream of an obstruction. The "ET" option was utilized to model - different encroachments for high and low flows. "GR" points were modified, where necessary, to model encroachments and non-effective flow areas within the flood plain. These non-effective flow limits are shown on the Figure 2 Comparison Cross Sections and on Figure 3. As can be seen from these cross - sections, the duplicate effective model showed flow in some areas beyond the current effective flow limits. -- In addition, the revised base hydraulic model was calibrated to recent floods. Severe flooding occurred in the Dallas/Ft. Worth area in the spring of 1989 and 1990. High water marks at the existing USGS Gage No. 08055500, immediately downstream of Sandy Lake Road and along Sandy Lake Road in the City of Carrollton were utilized as a comparison for calibration to the revised base hydraulic model. Table 4A-1 shows a list of the high water elevations and recorded discharges for these floods. TABLE 4A-1 HIGH WATER DATA _ 1989 AND 1990 FLOODS ELM FORK OF THE TRINITY RIVER -- DATE AGENCY ELEVATION DISCHARGE NOTES (MSL) (CFS) 05-17-89 USGS - gage 441.13 8,720 05-05-90 USGS - gage 444.88 27,600 Discharge measured at Belt Line Rd: 2605 cfs right bridge, 18916 cfs main _ bridge, 4097 cfs left bridge. 05-08-90 COE - City 444.82 Road sign on Sandy Lake Rd. west of of IH 35, east of Nursery; 2.6' from -- Carrollton bouom of sign. - Water surface elevations and flow distributions were also compared to: · C.O.E. model EF-CDC and the FEMA duplicate effective model SHELREV2; - · "Alignment Study of Belt Line Road from Coppell City Limits to IH-35E Project No. 490-402" prepared for the County of Dallas, January 1986; and · "Proposed Sandy Lake Road Improvements at Elm Fork Trinity River" prepared for the -'- City of Carrollton, March 1993. The fully developed watershed discharges developed by the Corps of Engineers for the - Reconnaissance Study were utilized for the Calibration model. The recorded discharge at Belt Line Road, May 1990 (Q=27600 cfs, Table 4A-2) is within one percent of the 10-year discharge used in the COE I-IEC 2 model, therefore the 10-year prof'fle was utilized for calibration to this high water mark. - A low flow of 8720 cfs was inserted into the model for calibration to the May 1989 high water mark. Attachment to Form 4 11-14 June 1994 Mannings 'n' values (roughness coefficients) and effective flow areas were utilized to calibrate to the high water marks and balance the flows through the obstructed flood plain areas. It was -- determined that the two recorded floods (1989 and 1990) were not large enough to cause the entire overbank area downstream of Sandy Lake Road to be effective. In fact, for the low flow (1989, Q=8720 cfs) conveyance is confined to the main channel throughout the model. The effective flow limits utilized -- for calibration to the 1990 flood are shown on Figure 3. Table 4A-2 shows a comparison of the high water marks and the computed water surface elevations at Sandy Lake Road. TABLE 4A-2 _ COMPARISON OF RECORDED VS COMPUTED WATER SURFACE ELEVATIONS ELM FORK OF THE TmNrry RJVER DISCHARGE RECORDED EFEXIST RECORDED RECORDED COMPUTED DATE WSEL Sandy Lake Road 8,720 441.13 441.70 05-89 Sandy Lake Road 27,600 ~.~.~..88 444.12 05-90 Sandy Lake Road (93750)~ 24,400~ 443.78~ See Note 1 Sandy Lake Road (93750)2 24,4002 442.452 See Note 2 x FEMA 10-year discharge from revised base model REVBASE. 2 FEMA 10-year discharge - Duplicate effective model SHELREV2. In addition to the calibration, flows in the two left overbank paths are balanced utilizing - the results of the split flow analysis prepared for Dallas County in January 1986 for the Belt Line Road Improvements. A 100 year flood discharge of 55,800 cfs based on a fully developed watershed was utilized for that study with a flow of 9500 cfs through the east (left) Belt Line Road Relief Bridge. Flows for the 100-year FIS discharge of 48600 cfs are balanced within 10% through existing Sandy Lake Road as shown in Table 4A-3. Attachment to Form 4 II-15 June 1994 TABLE 4A-3 FLOW DISTRIBUTZON - 100 YEAR FLOOD ELM FORK - TRINITY RIVER BELT L~NE THROUGH SANDY LAKE ROADS SECTION LEFT OVER BANK MAIN CHANNEL NOTES & ROB (CFS) 88160 7421 41,179 u/s, Belt Line Rd 88450 7893 40,707 89230 8274 40,326 90210 8611 39,989 91050 8338 40,262 92050 7193 41,407 92880 7825 40,775 93660 7973 40,627 93710 8699 39,901 93750 8724 39,876 Sandy Lake Road 93780 8933 39,667 Sandy Lake Road 93840 8895 39,705 93890 8928 39,672 Average 8285 40,314 _ Adjustments to Manning's "n" values, along with varying effective flow areas are utilized to balance these flows. Generally a 0.20 "n" value is utilized in the left bank flat area with a 0.18 in the small channel bordering the east City of Dallas property line. Flows are allowed to cross the levee along _ this channel downstream of Section 92880. The 'n' values transition to 0.10 in the left overbank downstream of Sandy Lake Road. Low areas such as the Dallas Water Utilities (DWU) sludge lagoons are modified with GR points to reflect non-effective flow below the top of the levees. GR points are _ also modified within the cross sections for non-effective flow areas such as the City of Carrollton Landfill area. - The existing dam and Sandy Lake Road cross sections are from the FIS duplication model. The overbank areas are modified using the new topography. Sandy Lake Road sections are also modified to reflect the top of the mad shown on the new maps. As with previous models, the culverts under - Sandy Lake Road at the DWU channel (east + 6000') are assumed to be non-effective for the 100-year flow. Comparison sections (Figure 2) are attached to this report which show the differences between SHELREV2 and the updated hydraulic model REVBASE. A diskette containing the revised existing - condition HEC-2 file is enclosed at the back of the report. Table 4A-6 shows a comparison of the 100- year water surface elevations for the duplicate and revised base hydraulic models. Attachment to Form 4 II-16 June 1994 In general, the revised existing conditions model reflects higher computed water surface elevations for the 100 year flood. This appears to be primarily the result of the more detailed modelling - with all fills and encroachments included in the topography. The revised modelling was submitted to the Fort Worth District Corps of Engineers (COE) in the report entitled "Sandy Lake Road Design Study, Hydraulic Analysis - Existing Conditions", August 1993. The COE has reviewed the HEC-2 model, but - has made no comments. The updated modelling is.utilized as the base hydraulic conditions for the proposed Sandy Lake Road improvements discussed in the following section. -- Proposed Condition Models (Appendix H and Appendix I): The Corrected Effective Hydraulic model with proposed Sandy Lake Road and downstream compensating excavation. The proposed flood plain and floodway is shown on Figure 4. Comparison cross sections are shown on Figure 5. Attachment to Form 4 II-17 June 1994 FORM 4 - RIVERINE HYDRAULIC ANALYSIS ATTACHMENT 4B - ANALYSIS OF 'N' VALUES Corrected Effective Models: Mannings 'n' values are modelled with NH cards in the corrected effective and proposed condition HEC-2 models to provide more detail in the extensive overbank areas (left overbank approximately 7000 feet wide downstream of Sandy Lake Road). Table 4A-4 shows a comparison of the IriS duplication model 'n' values and the channel and average overbank 'n' values from the revised base model. Mannings 'n' values are also shown on the Figure 2 comparison cross sections. TABLE 4A-4 ]~aANNING$ 'N' VALUE COMPARISON ELM FORK - TRINITY RIVER BELT LINE THROUGH SANDY L~,~:E ROADS FIS Duplication Revised Base Section Left Channel Right Section Left Channel Right Overbank Overbank Overbank Overbank 88150 0.!50 0.070 0.120 88160 0.130 0.070 0.130 88450 0.170 0.065 0.090 89050 0.080 0.075 0.060 89230 0.076 0.060 0.035 90000 0.080 0.075 0.060 90210 0.075 0.060 0.130 90880 0.080 0.075 0.060 91050 0.088 0.075 0.140 92090 0.080 0.075 0.060 92050 0.068 0.075 0.100 92300 0.080 0.075 0.060 92880 0.062 0.075 0.100 93620 0.070 0.060 0.060 93660 0.064 0.060 0.045 93670 0.070 0.060 0.100 93710 0.075 0.033 0.045 93730 0.070 0.060 0.100 93750 0.081 0.060 0.060 93760 0.070 0.060 0.100 93780 0.079 0.060 0.060 93810 0.070 0.060 0.070 93840 0.068 0.060 0.045 93890 0.067 0.060 0.045 97570 0.070 0.060 0.090 97710 0.054 0.060 0.045 98450 0.070 0.060 0.090 98460 0.070 0.060 0.090 98650 0.070 0.060 0.090 99280 0.070 0.060 0.090 99420 0.070 0.060 0.090 Attachment to Form 4 II-18 June 1994 In general, the averaged left overbank (LOB) 'n' values are similar to the composite values (NC card) utilized in the FIS duplication model. The channel 'n' values are also similar except in two areas. These areas are: · Sections 88450 through 90210 - the right channel banks have been cleared in this area by the Riverchase Development along the west bank of the Elm F. ork; and · Section 93710 - 'n' value lowered to 0.033. This is the existing concrete dam downstream of Sandy Lake Road. The right overbank 'n' values are significantly different in the revised base. Manning's 'n' values were lowered in this area due to the Riverchase Development which included clearing the area for a golf course and the construction of three lakes. However, the ground around these lakes is high causing obstructions, thereby limiting the conveyance capacity of the lake areas. In the reach including the - Carrollton Dam and Sandy Lake Road 'n' values are lower because in this reach the right overbank is cleared immediately adjacent to the channel. In addition, Manning 'n' values were used as part of the calibration process to balance the overbank flows as discussed in Attachment 4A. Representative photographs are attached to show the current Elm Fork channel and flood plain. _ Manning's 'n' values were generally kept the same for the revised base and proposed conditions except in the excavated areas and the reach containing the new bridge. However, since the proposed Sandy Lake Road embankment is above the 100-year water surface elevation flow in the far left overbank becomes non-effective, ie, the immediate left overbank becomes more effective. Since all flow is blocked east of the Carrollton Landfill, average 'n' values on the left bank are lower than those computed for the revised base hydraulic model. The 'n' values for propsoed conditions are shown on _ the Figure 5 cross sections. Attachment to Form 4 11-19 June 1994 Form 4 - Attachment 4B (con't) Photographs Existing Sandy Lake Road and Carrollton Dam Elm Fork Main Channel Near Belt Line Road Riverchase Golf Course Attachment to Form 4 I1-20 June 1994 iI I Fom~ 4 - Attachment 4B (con't) Photographs I I Near left (East) overbank. Proposed swale area. Carrollton Landfill in background. ! I Far left (East) overbank. Local Drainage Channel - I Dallas Water Utilities ~- : ! Attachment to Form 4 II-21 June 1994 Community Name: Cities of Carrollton, Coppell, Dallas TABLE 4A-5 WATER SURFACE ELEVATION CHECK Flooding Source: Elm Fork of the Trinity River Project Name/Identifier: Sandy Lake Road Effective * Duplicate Effective Corrected Effective Existing/Pre-Project Revised/Project SECNOs NCWSEL~ FCWSELa SURC.~ NCWSEL FCWSEL SURC. NC~VSEL FCWSEL SURC. NC'WSEL lmL-'WSEL SURC. NCWSEL FCWSEL SURC. 85000 439.25 439.28 0,03 439.25 439.28 0.03 439.28 439.28 0.00 439.28 439.28 0.03 86560 439.47 439.49 0.02 439.47 439.49 0.02 439.49 439.49 0.00 439.49 439.49 0.00 87530 439.52 439.54 0.02 439.52 439.54 0.02 439.54 439.54 0.03 439.54 439.54 0.03 87800 439.62 439.64 0.02 439.62 439.64 0.02 439.64 439.64 0.00 439.64 439.64 0.00 87869 439.72 439.74 0.02 439.72 439.74 0.02 439.74 439.74 0.00 439.74 439.74 0.03 87870 439.72 439.74 0.02 439.72 439.74 0.02 439.74 439.74 0.00 439.74 439,74 0.00 87960 440.24 440.26 0.02 440.24 440.26 0.02 440.26 440.26 0.00 440.26 440,26 0.00 87961 440.25 440.26 0.01 440.24 440.26 0.02 440.26 440.26 0.00 440.26 440.26 0,03 88000 440.34 440.35 0.01 440.33 440.35 0.02 440.35 440.35 0.03 440.35 440.35 0.00 88030 440.47 440.48 0.01 440.47 440.49 0.02 440.49 440.49 0.03 440.49 440.49 0.00 88050 440.55 440.56 0.01 440.54 440.56 0.02 440.56 440.56 0.03 440.56 440.56 0.00 88150/88160 441.09 441.10 0.01 441.09 441.10 0.01 440.82 440.79 -0.03 440.82 440.82 0.00 188450 441.44~ 441.45~ 0.01 441.455 441.45~ 0.01 442.23 442.32 0.09 442.26 442.26 0.00 890~0/89230 442.37 442.39 0.02 442.37 442.39 0.02 443.28 443.41 0.13 443.16 443.16 0.03 90000/90210 442.83 442.86 0.03 442.83 442.86 0.03 443.62 443.78 0.16 443.61 443.61 0.00 90880/91050 443.67 443.68 0.01 443.67 443.68 0.01 443.98 444.17 0.19 443.90 443.90 0.00 92090/9'2050 444.14 444.15 0.01 444.14 444.15 0.01 444.65 444.86 0.21 444.30 a44.30 0.03 Comments: * Effective model as provided by FEIv',.A P~j~ct Library - Carmllton FIS Update, Dec~nb~' 18, 1991. ' 100-y~ax (natu~) Watex Surfa~ Elevati~ 2 F, nc~ach.n~t (floodway) Waist Suffa~ Elevation ~ Stuc, haxge Valu~ 4 Effectiw / Rm, iaed ae~tion nan,, ~ueclive, ly ~ Inttalmlated Elmeati~m Note: Effective and Duplicate Effective WSEL's from Elm Fork Trinity River floodway model as provided by FEMA Project Library. This model includes an incorrect shafting WSEL at Section 64820 (see Attachment 4A). II-22 Community Name: Cities of Carrollton, Coppell, Dallas TABLE 4A-5 (cont.) WATER SURFACE ELEVATION CHECK Flooding Source: Elm Fork of the Trinity River Project Name/Identifier: Sandy Lake Road Effective * Duplicate Effective Corrected Effective Existing/Pre-Project Revised/Project SECNO~ NCWSEL~ FCWSELm SURC.) NCWSEL FC%VSEL SURC. NCWSEL FCWSEL SURC. NL'~SEL FCWSEL SURC. NCWSEL FCWSEL SURC. 92300/ 444.22 444.22 0.00 444.21 444.22 0.01 /92880 445.02 445.24 0.22 444.43 444.43 0.00 93620/93660 445.02 445.51 0.49 445.02 445.51 0.49 445.62 445.87 0.25 444.75 444.75 0.00 93670/93710 445.14 445.70 0.56 445.14 445.70 0.56 445.60 445.82 0.22 444.72 444.72 0.00 93730/93750 445.22 445.87 0.65 445.22 445.87 0.65 446.00 446.56 0.56 445.01 445.01 0.00 93760/93780 445.36 446.01 0.65 445.36 446.01 0.65 446.29 446. 80 0.51 445.12 445.12 0.00 93810/93840 445.51 446.08 0.57 445.51 446.08 0.57 446.68 447.22 0.54 445.25 445.25 0.00 /93890 445.52~ 446.09~ 0.57 445.52~ 446.09~ 0.57 446.71 447.25 0.54 445.29 445.29 0.00 97570/97710 446.31 446.95 0.64 446.31 446.95 0.64 447.34 447.86 0.52 446.66 446.66 0.00 98450/98460 446.50 447.09 0.59 446.50 447.09 0.59 447.53 ' 448.02 0.49 447.01 447.01 0.00 98650/ 446.56 447.14 0.58 446.56 447.14 0.58 99280/99420 446.74 447.30 0.56 446.74 447.30 0.56 447.89 448.33 0.44 447.54 447.54 0.00 100040 447.01 447.56 0.55 447.01 447.56 0.55 448.04 449.49 0.45 447.73 447.77 0.04 104600 448.11 448.42 0.31 448.11 448.42 0.31 448.70 449.21 0.51 448.50 448.78 0.28 105530 448.69 448.94 0.25 448.69 448.94 0.25 449.13 449.56 0.43 448.97 449.22 0.25 106080 449.08 449.29 0.21 449.08 449.29 0.21 449.45 449.84 0.39 449.32 449.5:3 0.21 110580 450.74 450.85 0.11 450.74 450.85 0.11 450.88 451.16 0.28 450.83 451.03 0.20 Comments: · Effective model as pmvid~ by FEMA Project Library ~ 100-year (mm.nd) Wafer Surface Elevation a Enmmachmont (floodway) Wa~' Surface Elevation ~ Sumhsxg¢ Value a Effe~'dve / Revis~ section names, ~vely ~ Inte~ct~d Elevation 11-23 ~, TABLE 4A-6 COMPARISON OF COMPUTED BASE FLOOD ELEVATIONS -- FEMA (EXISTING LANDUSE) DISCHARGES SANDY LAKE ROAD BRIDGE -- BASE MODEL REVISED BASE MODEL SHELREV2 [note 11 REVBASE [note 2] _ !!'.':':~,'..'!~?!!?!~! 439.28 ::iii!i!!i~!!~!i::!ii!i~i::i 439.28 0.00 ;: ~.: :;:; :~'::~ :~:.::: ~: :~::: ~ ~::'":'"":'"":'":':'"::i: :: :.:.:~,~.~:::,:;.:8.~:439.64 !~i~i~i!ii~!!ii~iii 439.64 0.00 -- :.,'.~..'.::~:.::~:i.8. :'~.:~" ::?:~ ~.:~---- - r - - -.:.- '.'- '.-.: 439,74; ~::~.-'..~:~:~?~78~~':~:~:*::~:'": :~::~.~:?::-' '.r--'--.-'-'-'.~:~ 439.74 0.00 BELT LINE ROAD i:~i!~}~¢iiiii!ili~..'~i 439.74 ! ~iii~iiiii/!!i!i~i!i~-'7:..Oi!i 439.74 0.00 ~::.-'::~i~:::-i~i~i~i~i!i!ii::i:; ....................... i 440.35 :!:~:~:~i.-:.:~..-i:i~!:~!~ ....................... ~:~ 440.35 0.00 RAILROAD ::i;i::{:iii:i;i:i::i:i:i::;;::i~i 440.49 i?~ii!i;;!~;i:~:~ii?~ii:~i;~;~:~:~ ~I~:~ 440.49 0.00 :.:.,,:.:.:-:.:.:.r.:.:...:.:.:?;.;?;.F.:.:.:.:.H.:. ::.::::::::::,~:::::::::::::::::::::::::::::::::: ...... '~ '!'!'!.14!!!i!i!i!i!i!i!!i!!i!!!i!i!i!~!!i '!'!4.65 0.51 :i:!: :~:::~ ~,:~ ~.::~ ~.:: ..................... : ~.~:~.-'{'~'..~?.~..':i:.~:"":""~'""'":: '-'.~:~:+:~. .................. i'~ ~¢i'~:..:.i~ { ~' ~.:i .................. i:'"'"':!' 60" WATER LINE AERIAL !:~-:.:'.,.-'~i=...'*..'..'~i~i 445.52 :;:;:.:::.,. .............. ~::: 446.68 1.16 :::i::::i::.:i::..:::.:-: ?:.:?~..:-:?:,.:?:,::~-?::~0,.' ::::::::::::::::::::::::::::::::::::::::::: 44671 -- ~: ~ ~;'"~'"~ ~ ~ .............. ::~: 446.31 447.34 1.03 i;::::':':i;'::':~;::':::;~::;::i;ili~i;i 446.50 iiiiii!iiii!iiiiiiiiliiiiii!iii~;i 447.53 1.03 Note: [1] Shortened version of HEC-2 model provided by FEMA PROJECT LIBRARY - _ CARROLLTON FIS update 12-18-91. This model is also the effective model for the City of Coppell FIRM dated 4-15-1994. Note: [2] Revised base model with X-sections 88160 through 99420 from 1991 Feasibility Study topographic mapping. 06/29/94 17:30 29 11-24 TABLE 4A-7 COMPARISON OF COMPUTED BASE FLOOD ELEVATIONS AND CHANNEL VELOCITIES FEMA (EXISTING LANDUSE) DISCHARGES SANDY LAKE ROAD BRIDGE BASE MODEL REVISED BASE MODEL PROPOSED MODEL SI' --LREV2 [not, 1! REVB/ SE [note 2] SHELPF ~) [note 31 DESCRIPTION iiiii!i!~i::?:il WSEL VEL ::i::iiiiiii~ ~i!iii:: WSEL VEL ::!iiiiili~T..:iiiii:: WSEL VEL dWSEL ::!i!iiiiiii!i!iiiii~:: 439,49 1.58 ::::::::::::::::::::::::::::::: 439.49 1.58 ::!::iiiiiii::iiiiiiiii~:: 439.49 1.58~ 0.00 ::i!::iiiiiiiiiiiiii!::~.'~:: 439.54 5.73 ::::i!::::::ii!::!i!i!i!::!i!~ 439.54 5.73 ::::::::::::::::::::::::::::::::: 439.54 5.73! 000 BELT LINE I::IOAD ::iii!i!~!::ii!i!ii~:: 439.74 7.82 iiiiiiiiii::iii::i~ii~ 439.74 7.82 ;ililililiiii::i::::ii::iii~:: 439.74 7.82 0.00 RI=I T LIN[;: ROAD ::i::i!i~iiii~ii~!~:: 440.26 7.41 ii!iii!iii!iiiii~ 440.26 7.41 iii!iii::?:i!i::?:?:?:i~i 440.26 7_41 000 [ii![iiiiiiiiiii[;"~-'"~f::i 440.~ 7,40 I::i!i[iii!i~i~ii~i~.~[i 440.26 7.40 ?:::::::::::?:::::::::::::::::: 440.~ 7.40 0.00 ::?:ii!::i~ili!ii::i~i 441.10 6.55 ::i!i!i!i!iiiiiii~ii~"~ 440.82 8.85 ::ili::ilili::i::i::iiiii~!i 440.82 8.85 0.00 ::[i[i!iiii!i!~[~ 44,3,{7 2_73 ?:~i~i~i.~ ~,~443.98 -~ 3.86 ::ii::i::[~!iiiiii::[[~i~::i 443.~ 3.33 -O.08 :::::::::::::::::::::::::::::::: aa~02 4_~4 ii!i::::~/~ d,~LRRP ROd. iiiii[ililili~!i!~! 4447~ 4~ -0_87 CARROLLTON DAM ifiii!ii~i!i~i!ii~i 445.14 3.71 ::!iii!iiii!iiii~i ~?..;~ 445.60 8.44 ':ii!i!ii!ii::ii!iiii::~:: 444.72 7.19 -0.88 60" WATER UNE AERIAL i:::~iiii!:~iiiii:~ii!:~i~i 445,~:g 3.54 ::!::iii::fiiiii::i::i~i 446.68 3,22: ::::::::::::::::::::::::::::::::: 445.25 4.74 -1.43 ::::!::ii::iliiii!ii iii~ ~! 446.50 2.41 ::!::ii[ii::iiii!~'~ili~ 447.53 ::::::::::::::::::::::::::::::::::::: 447.01 3.59 -0.52 ::?:ii?:ii!::i::::iiiii!~:: 446.74 236 i::i::iiiiiiii:.}iii::~ 447.89 2.2o :::::?:::::::?::::?::::::: 447.54 2.46 .0 35 ::::::::::::::::::::::::::::: 44869 3.94 ::!i!::iiiiiiiiiii::~ 449.13 3.62 ::::::::::::::::::::::::::::: 448_97 3_72 -0.16 Note: [1] Shortened version of HEC-2 model provided by FEMA PROJECT UBRARY- CARROII TON FIS update 12-18-91. 17:31:42 Note: [2] Revised base model with X-se~ons 88160 through 99420 from 1991 Feasibility Study topographic mapping. 06/29/94 Note: [3] dWSEL comparison to revised base model REVBASE 11-25 TABLE 4A-8 COMPARISON OF COMPUTED 100-YEAR FLOOD WATER SURFACE ELEVATIONS FULLY DEVELOPED LANDUSE DISCHARGES SANDY LAKE ROAD BRIDGE BASE MODEL REVISED BASE MOl)EL PROPOSED MOOEL DESCI:IIPTION EF-CDC [note 11 EFEXRV6 [note 21 EFPROP17 WSEL [i.-';:~i~!~i~i~::I WSEL I dWSEL ~::[i~i~)~J~.~;:~i~i~ii WSEL I dWSEL [COL 1] lCOL 2i ICOL 31 :: ~:;~:i:i:~.=:: ...................... l~i~!iii!~ii!iii!!!i!~: 444.82'...... :: .................. ........................... ==================================================.~i!~.~:i~iii.<i:i:!:i:i:i:i:!:i:i:i:i:i ?:i::ii::?:?:iii::iiiii::?:i::~i 445.71 4 ~ ~/ i::i::iiiii[iiiiiiiiiiii!ii~i 445.19 -0.,52 i!!iiiiiitii::i::iiii!ii::~ 445.~ iii?:i::iii::?:i::!::?:ii{::i~i 44s.~0 4-~,.o; 0.7o !iiiii~iliiiiiiiiii::i~i 44.5.52 -0.7e ::::::::::::::::::::::::: ~52.e~ :::::::::::::::::::::::::::: 452.~ 0.00 ::i:!::i~ii!i~::ili!i!?:i~::~i~ 452.81 0.00 ii::!::i::ff:!::!ii!::::~:-~i~ 452.84 :::::::::::::::::::::::::::::: 452.83 -0.01 iii!i::i::iiiiii::i!!ili?:ii~ 452.83 0.00 ii?:iii~i~iii::iiiii::ii?:~::~ 4,52 ~ ii?:i~iiiiii?:iii!!iiii~::~:: 452_84 43.01 ::iii::i::iii::i::iii::i~iiii~i~ 4,~2 ~ 0 oo ............ 06/2g/g4 17:33:20 [note 1]: SHORTENED VERSION OF COE TRINITY RIVER RECONN STUDY MODEL, EF-CDC. [note 2]: REVISED BASE MODEL WITH X-SECTIONS 88160 THROUGH 99420 FROM 1991 FEASIBILITY STUDY TOPOGRAPHIC MAPPING. dWSEL ~ARISON TO BASE MODEL EF-CDC. 11-26 TABLE 4A-9 COMPARISON OF COMPUTED SPF WATER SURFACE ELEVATIONS FULLY DEVELOPED LANDUSE DISCHARGES SANDY LAKE ROAD BRIDGE SPF FLOWS BASE MODEL REVISED BASE MODEL P~ MODEL DESCRIPTION EF-CDC EFEXRV6 [note 11 EFPFIOP17 [( 1lcoL 1 [COL. 2! ICOL 31 ::iiiii::i::iiiiiii::iii::!::iii~ 449.34 i::i::i::iiiii::iiiiiii::i::iiiii~ 45o. 19 0.85 iiiiiii::i::iii}::iiiii::iii~il 4,50_o9 -0.10 U/S PROPOSED SANDY LAKE RD !::i!iii::!!i!i::!!i!!!i::iiiii~ 450.55 i!::i::!ii::!::iiii!::iiiii::i!ii~ 451 58 1.133 ::i!!!!!!!i!!!i!ili!i!i[ii~il 451.15 -0.43 60' WATER LINE :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: ::::::::::::::::::::::::::::::::::::::::::: 451,66 [i!ii!i[i!i::i::iii::i[i[i[i~! 451 _48 43.18 DENTONCREEKCONFLUENCE ii[iii[i!i::i::?:i!i::iiii!ii[~ 4,50,94 i!i::!::!ii!ii!i?:i!!::i::i!i::i~ 451,~ 1.01 i::i::!::iii::i::iiii![iii::iii::!~i=, 452.01 0.06 ::::::::::::::::::::::::::::::::::::::::::::::::: 451.0~::?:!i!::i::ii?:ii?:iii::?:i::~ 452.05 1.01 ::iiiii::i::!ii::iii::iii::i::iii::~::! 452.12 0.05 :::::::::::::::::::::::::::::::::::: 451.$5:::::::::::::::::::::::::::::::::::: 45~.~ 1,05:::::::::::::::::::::::::::::::::::: ,~..45 0.05 ::!ii~i::i::i::i::i~i::i~i::i::~i 452.0e :::::::::::::::::::::::::::::::::: 4,5;~,~1 0.83!~i::i::i::i::i::i~!::i::iii::i::~i 452.9~ 0.05 ::::::::::::::::::::::::::::::::::::: 453.67 ::!i!i!i!i!!!::!::ii!::!::!::!~ 454,07 0.4oii::i::i!i::ili::!::i::i!i::!!~i 454.~0 0.03 i::![iiiiiii::iiiii::::i::i::::~::~:: 455.09 ::::::::::::::::::::::::::::::::::::::: 455.31 0.22::i[i!!::!i!i!::!ili!::ii~!~:: 455.33 0.02 i::::iiiii::iiiiiiiii?:!~::.:'i~i~i 455.24 :::::::::::::::::::::::::::::::::::::::::: 455.56 0.32 ::[ii::i::i::iii::iii::i::i::i~::~i~i 455.56 0.02 MKTRAILROAD :::::::::::::::::::::::::::::::::::::::: 456.09 ::::::::::::::::::::::::::::::::::::::::::: ,~,~,:~0 0.21 iii[ii[i[iliiii[iiii~i.~i 456.321 0.02 HEBRON PARKWAYLEVEE ii[ii::i[::!iii::i::::i::::i::::~i~=: 457.12 :::::::::::::::::::::::::::::::::::::::::: 457.26 0.14 !!iiiiiii::!ii[i!!::!!~::~:: 457.27 0.01 ('rOPOFLEVEE=454.45) !ii[i[iii::i[i::i::i::i::iii~" 458.05 ::iiiiiii::iii[::i[iii::ii~i 458.16 0.11 ::i[iii::i::!::iii::i[i[iii~i 458.16 0.00 ....... ' .72 . .......... ::::::::::::::::::::::::::::::::::::::::::::::::: .:.:,:.:,:.:.:.:.:.:.:.:,:.:.:,:.:.:.:.:,:.:,:.:.: :::::::::::::::::::::::::::::::::::::::::::::::: :.:.:.:,:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:,:.:.:. :i:i:~:i:i:i:i:i:i:i:i:i:i:i:i:i:i:i:i~i:'::i:i:i:i .:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.;.:.:.:.:.:.:.: :::::::::::::::::::::::::::::::::::::::::::::::::: [note 1]: REVISED BASE MODEL WITH X-SECTIONS 88160 THROUGH 99420 FROM 1991 FEASIBILITY STUDY TOPOGRAPHIC MAPPING. 17:35:16 11-27  FEMA USE ONLY FORM 5 RIVERINE/COASTAL MAPPING FORM Community Name: City of Carrollton, Texas Flooding Source: Elm Fork of Trinity River Project Name/Identifier. Sandy Lake Road at Elm Fork, Trinity River 1. A topographic work map of suitable scale, contour interval, and planimetric definition must be submitted showing (insert N/A when not applicable): Included A. Revised 100-year flood plain boundaries (Zone A) Figures 4 & 7 ~ Yes [] No [] N/A B. Revised 100- and 500-year flood plain boundaries Figures 4 & 7 [] Yes [] No [] N/A C. Revised 100-year floodway boundaries Figures 4 & 7 [] Yes [] No [] N/A D. Location and alignment of all cross sections used in the revised hydran!ic model with stationing conU'ol indicated Figure 3 & 4 [] Yes [] No m N/A -- E. Stream alignments, road and do_m alignments Figure 4 [] Yes [] No [] N/A F. Current community boundaries Figure 1 [] Yes [] No m N/A G. Effective 100- and 500-year flood plain and 100-year floodway _ boundaries from the FIRIVI/FB~ reduced or enlarged to the scale of the topographic work map Figure 7 [] Yes [] No [] N/A H. Tie-ins between the effective and revised 100- and 500-year flood plains and 100-year floodway boundaries Figure 7 ~ Yes m No [] N/A -- I. The requestor's prolxn'ty boundaries and community easements Fig.1 [] Yes [] No [] N/A J. The signed certification of a registered professional engineer Form 1 ~ Yes rm No I3 N/A K. Location and description of reference marks Figure 3 [] Yes [] No [] N/A -- L. Vertical Datum (example: NGVD 1929, NAVD 1988, etc.) Figure 3 [] Yes [] No [] N/A M. Coastal zone designations fie into adjacent areas not being revised [] Yes [] No [] N/A N. Location and alignment of all coastal transects used to revise the coastal analyses [] Yes [] No [] N/A If any of the items above are marked no or N/A, please explain: Not in Coastal Zone 2. What is the source and date of the updated topographic information (example: orthophoto maps, July 1985; field survey, May 1979, beach profiles, June 1987, etc.)?Aerial topography flown February 1991 3. What is the scale and contour interval of the following workmaps? -- a. Effective FIS 1"=1000' scale ..... Contour interval b. Revision Request 1"--400' scale 2 ft Contour interval -- Note: Revised topographic information must be of equal or greater detail. November 1992 II-28 Page 1 of 3 AlaPLICATION/~BRTIFICATION FORM~ FOR CONDITIONAL L~rll~R OF MAP REVISION, L~II'I:~ OF MAP REVISION A.ND PHYSICAL MAP RBVI~ION R1VF_ltlNE~O~T~ MAPPING FORM Mapping Changes (Cont'd) 4. Attach an annotated FIRM and FBFM at the scale of the effective FIRM and FBFM showing the revised 100-year and SOO-year flood plains and the 100-year floodway boundaries and how they tie into those shown on the effective FIRM and FBFM downstream and upstream of the revision, or adjacent to the area of revision for coastal studies. Figures 7A thru 7D Atto_ch additional pages if needed. 5. Flood Boundaries and 100-year water surface elevations: Has the 100-year flood plain been shifted or increased or the 100-year water surface elevation increased at any location on property other than the requestor's or community's? maximum increase 0.03 feet [] Yes [] No If yes, please give the location of shift or increase and an explanation for the increase. WSEL increase of 0.03 feet at Section 88450 due to non-effective flow caused by Sandy Lake Road embankment. a. Have the affected property owners been notified of this shift or increase and the effect it will have on their property? [] Yes [] No ff yes, please aUach letters from these property owners stating they have no objections to the revised flood boundaries. Conditional LOMR requested. Adjacent property owners will be notified prior to construction. Adjacent community notifications are included in Appendix B. b. What is the number of insurable structures that will be impacted by this shift or increase? 0 6. Have the floodway boundaries ~ or increased at any location compared to those shown on the effective FBFM or FIRM?. [] Yes [] No If yes, explain: Proposed floodway (left overhank) set at effective flow limits due to Sandy l.ak¢ Road embankment. 7. ff a V-zone has been designated, has it been delineated to extend landward to the heel of the primary frontal dune? NIA [] Yes [] No ff no, explain: 8. Manual or digital map submission: [] Digi~ Digital map submissions may be used to update digital FIRMs (DFIRMs). For updating DFIRMs, these submissions must be coordinated with FEMA Headquarters as far in advance of submission as possible. November 1992 Il- 29 Page 2 of 3 AP~LICATION/CltRT~ICATION FORMS FOR CONDIIIONAL L~ri~R OF MAP RIiVISION, L~A-IltR OF }~AP RBVISION AND PHYSICAL MAP RItVISION RIVERINE/COASTAL MAPPING FORM Earth Fill Placement 1. Has fdl been placed in the regulatory floodway? [] Yes [] No Sandy Lake Road Embankment If yes, please auach completed Riverine Hydraulic Form. 2. Has fill been placed in floodway fringe (area between the floodway and 100-year flood plain boundaries)? [] Yes [] No Sandy Lake Road Embankment If yes, then complete A, B, C, and D below. A. Are fill slopes for granular materials steeper than one vertical on one-and-one-half horizontal? [] Yes [] No ff yes, justify steeper slopes B. Is adequate erosion protection provided for fill 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 ra No If no, describe erosion protection provided Concrete side slopes at bridge abutments and -- rip-rap erosion protection under bridge. C. Has all fill placed in revised 100-year flood plain been compacted to 95 percent of the maximum -- density obtainable with the Standard Proctor Test Method or acceptable equivalent method? N/A, CLOMR. Compaction tests will be provided with Final LOMR submittal. [] Yes [] No D. Can structures conceivably be constructed on the fill at any time in the future? Fill for road embankment only. [] Yes [] No - ff yes, provide certification of fill compaction (item C. above) by the community's NFIP permit official, a registered professional engineer, or an accredited soils engineer. _ 3. Has fill been placed in a V-zone? NIA [] Yes [] No If yes, is the fill protected from erosion by a flood control structure such as a revetment or seawall? ~n Yes [] No If yes, attach the coastal structures form. November 1992 II-30 Page 3 of 3 API:LICATION/CERTIFICATION FORMS FOR CONDITIONAL LETTER OF MAP REVISION, LiiTrER OF MAP REVISION AND PHYSICAL MAP REVISION Form 5 - Riverine/Coastal Mapping Attachment 5A - Mapping Changes Revised Flood Plain and Floodway Boundaries The change in the 100-year water surface elevation within the project reach is less than one (1) foot. At the scale of the FIS maps (1"=1000 feet) this change in. water surface elevation is not mappable. However, there are numerous small islands (high areas) within the Elm Fork flood plain which are not shown on the current FIRM. These areas are shown in detail on Figure 4, Appendix A. The revised floodway within this reach is set at the effective flow limits in the left (east) overbank. This effective flow limit is determined by the proposed bridge opening since the Sandy Lake Road embankment will be above the 100-year water surface elevation. All flow in the far east overbank (east of the Carrollton Landfill) will be non-effective because of the proposed road embankment. The proposed Floodway is shown on Figures 7A, 7B, 7C, and 7D. Attachment to Form 5 11-31 June 1994 FEMA USE oNLY FORM 6 CHANNELIZATION FORM Commtmity Name: City of Carroll~on, Texas Flooding Source: Elm Fork of Trinity River Project Name/Identifier. S0ndy I rake Ro_ad~ at F~lm Fork~ Trinity River Extent of Channelization - Overbank only Downstream limit Section 88160 (excavation only) Proposed swale starts at Section 90210. Upstream limit Section 93890 Channel Description 1. Describe the inlet to the channel Compensating excavation in left overbank. Inlet is an existinE ditch, approximately 5 ft deep and 15 ft wide, along City of Carmllton Athletic field at Section 93890. 2. Briefly describe the shape of the channel (both cross sectional and planimelric configuration) and its lining (channel bottom and sides) Grass-lined linear swale 0~ottom elevation 430.0, effective side slope 4:1) from Section 90210 to ~640 ft downstream of section 93660; grass-lined -- lon~ated swale (bottom slope 0.5% side slope 4:1) from i-640 ft downstream of Section 93660 to 200 ft upstream of Section 93890; grass-lined excavation along east edge of swale 00ollom elevatinn 437.0, side slope 4:1) from +400 ft downstream of SectiOn 93660 to Section 93840. _ (see Figx~re 5 Cross Sections) 3. Describe the outlet from the channel Overflow draining into Elm Fork of Trinity River at Section 92880. 4. The channelization includes: _ [] Levees [] Drop structures [] Superelevated sections O Transitions in cross sectional geometry o Debris basin/detention basin [] Energy dissipater [] Other Swale/Pond compen~fin~ excavation. 5. Attach the following: _ a. Certified engineering drawings showing channel alignment and locations of inlet, outlet, and items checked in Item 4. Figure 4 b. Typical cross sections and profiles of channel banks and invert. Figures 5 & 6 c. Certified engineering drawings of items checked in Item 4. Figure 4 October 1992 Page 1 of 3 _ II-32 ~CATION/t:~I~TIPI~ATION PORMS POR CONDITIONAL L~l-i t:~. OF MAP RI~'VISION, L~YI't~ OP MAP REVISION AND PHYSICAL MAP REVISION CHANNELIZATION FORM Hydraulic Considerations 1. What is the 100-year discharge? 48600 cfs 2. Do the cross sections in the hydr'aulic model match the typical cross sections in the plans? [] Yes [] No 3. Are the channel banks higher than the 100-year flood elevations everywhere? no change to main channel, compensating ra Yes [] No excavation only 4. Are the channel banks higher than the 100-year · flood energy grade lines everywhere? [] Yes [] No 5. Is the land on both sides of the channel above the adjacent 100-year flood elevation at all points along the channel? [] Yes [] No 6. What is the range of freeboard? compensating swale only 0 feet 7. What is the range of the 100-year flood velocities? 3.8 - 7.6 fl/sec 8. What is the lining type? (both bottOm and sides) l~rass, rock rip-rap as needed Explain how the channel lining prevents erosion and maintains channel stability (attach documentation) Recommended rock rip-rap at all locations where velocities exceed 5 fl/sec (max V--5.7 fps in swale under bridge) 9. What is the design elevation in the channel based on?: [] Subcritical flow [] Critical flow [] Supercritical flow [] Energy grade line Is the 100-year flood profile based on the above type of flow? [] Yes [] No If no, explain: 10. Is there the potential for a hydraulic jump at the following locations? Inlet to channel ra Yes [] No Outlet of channel [] Yes [] No At Drop Structures [] Yes [] No At Transitions [] Yes [] No Other locatior~ Explain: If th~ answer to any of the above is yes, please explain how the hydraulic jump is controlled and the effects of the hydraulic jump on the stability of the channel. Explain: October 1992 Page 2 of 3 11-33 AI~LICATIOI~T~ICATION PORMS FOR CONDmONAL L~i-l~x OF MAP REVISION, I2/Fl'lta O~ MAP REVISION AND ~IY~ICAL MAP REVISION CHANNELIZATION FORM Sediment Transport Considerations 1. A. Is there any indication from historical records that sediment transport (including scour and deposition) can affect the lO0-year water-surface elevations and/or the capacity of the channel? [] Yes [] No B. Based on the conditions of the watershed and stream bed, is there a potential for sediment transport (including scour and deposition) to affect the lO0-year water-surface elevations and/or - the capacity of thc channel? [] Yes [] No 2. ff the answer to either lA or lB is yes: A. What is the estimated sediment Coed) load? ~ cfs (attach gradation curve) Explain method used to estimate load B. Is the 100-year flood velocity anywhere within the -- channel less than the 100-year flood velocity of the inlet? [] Yes [] No C. Will sediment accumulate anywhere within the channel? [] Yes r~ No D. Will deposition or scour occur at or near the inlet? [] Yes [] No E. Will deposition or scour occur at or near the outlet? [2 Yes r2 No October 1992 ii_3/4 Page 3 of 3 APPLIG4,TION,/CERTIFI~.TION PORM~ FOR CONDITIONAL L~[rl't~R OF MAP RKglSION, LgYrlffi OF MAP RI~I~iON AND PHYSICAL MAP R~VISION FORM 7 BRIDGE/CULVERT FORM* Community Name:City of Carrollton~ Texas FlOOding Source: F. im Fork of Trinity River Project Name/Identifier. Sandy Lake Road at Elm Fork, Trinity River Identifier 1. Name of roadway, raikoad, etc.:. _ Sandy Lake Road - 2. Location of bridge/culvert along flooding source (in terms of stream distance or cross-section identifier): proposed bridge replaces existing bridge currently located at section 93730-93760 in FIS Model. 3. This revision (check one of the following): [] New bridge/culvert not modeled in the FIS [] Modified bridge/culvert previously modeled in the FIS -- [] New bridge/culvert previously modeled in the FIS (Explain why new analysis was performed.) New bridge with low be_om 2' above 100-yr WSEL as part of improvements to raise _ Sandy I,ge Road out of 100-yr floodplain. -- Background Provide the following information about the stmctare: 1. Dimension, material, and shape (e.g. two 10 x 15 feet reinforced concrete box culvert; three 30-foot span bridge with 2 rows of two 3-foot diameter cimul_ar piers; 40-foot wide ogee shape spillway) - Two 120-ft span and ten 80-ft span bridge with 3-ft diameter circular piers 2. Enuance geomeu'y of culvert/type of bridge opening (e.g. 30° - 75° wing wails with square top edge, sloping embankments and vertical abutments) Bridge with circular piers aligned with flow. 3. Hydraulic model used to analyze the smacture (e.g., HEC-2 with special bridge routine, - WSPRO,I-IY8) HEC-2 with normal bridge murine If different than hydraulic analysis for the flooding source, justify why the hydraulic analysis used - for the flooding source could not analyze the slmcture(s). (Attach explanation) Note: If any items do not apply to submitted hydraulic analysis, indicate by N/A. _ * One form per new/revised bridge/culvert October 1992 11-35 Page 1 of 6 APPLICATION/E~RTIFICA'rXON FORMS FOR CONDITIONAL L~rr~R OF MAP REVISION. L.~l-ll~R OF MAP REVISION AND PHYSICAL MAP RBVI~ION BRIDGE/CULVERT FORM Analysis Sketch the downstream face of the structure together with the road profile. Show, at a minimum, the maximum low chord elevation, invert elevation, and minimum top of road elevation. See Figure 8 - Plan View and Cross Section of Proposed Sandy Lake Road Bridge. Sketch the upstream face of the structure together with the road profile. Show, at a minimum, the maximum low chord elevation, invert elevation, and minimum top of road elevation. See Figure 8 - Plan View and Cross Section of Proposed Sandy Lake Road Bridge. Note: Downstream and Upstream face are identical. October 1992 Page 2 of 6 11-36 APIaLICATION/Ut~TIFICATION FOR3,fS FOR ~ONDIT'IONAL ~ OF MAP RBVISION, ~ OF MAP RI~'ISION AND PHYSICAL MAP RBVISION BRIDGE/CULVERT FORM Analysis (Cont'd) Sketch the plan view of the strucUu~s). Show, at a minimum, the skew angle, cross-section locations, _ distances betw~n cross sections, and length of structure(s). NOTE: Pi-E..R~ ALt, CaNE-.-D k,,,/tTH FLOX.d. <--- flOW ',';. 4 ~; " -- 0 ~l ~ Attach plans of the slructure(s) c~rtifi~l by a r~gist~r~d Professional Engineer. NIA Condirionat LOMR Preliminar~ layout sfio~n on Figure 8, Appendiz A~ Culvert length or bridge width (ft.) 80 ft* Calculated culvert/bridge area (ft:) by the hydraulic model, ff applicable (@ lO0-year WSEL) Area=9241.57 ft: d/s, 9343.21 ft: u/s Total culvert/bridge area (lC) 12r211. - * Bridge length 1040 feet. See Figure 8. October 1992 11-37 Page 3 of 6 APPLICATIONfl~I~RTIFICATION PORMS FOR CONDITIONAL Lia-Fl~lle.. OF MAP REVISION. LI~i-iI~R OF MAP REVISION AND PHYSICAL MAP REVISION BRIDGF./CULVERT FORM Analysis (Cont'd) Elevations Above Which Flow is Effective for Overbanks Left Ov~rbank Right Overbank Upstream face. 433.5 448.0/452.0 Downstream face 433.5 448.0/452.0 Minimum Top of Road Elevation Left Overbank Right Overbank Upsl~am face 447.0 (far left) - 452.0 (top of road) Downstream face 447.0 (far left) 452.0 (top of road) 100-Year Elevations Water-Surface Energy Gradient Elevations Elevations Upstream face 445.12 445.54 Downstream face 445.01 445.44 Discharge Low Flow Pressure Flow Weir Flow Total Flow Amount of flow through/over the structure(s) (cfs) 48600 N/A N/A 48600 The maximum depth of flow over the roadway/ raitroad (f~} N/A Weir len~h (ft.} N/A Top Widths Floodplain Floodway Upstream face 1013 ft 1013 ft Downstream face 1013 ft 1013 ft Topwidth at Low Chord elevation = 1040 feet with 2 feet of freeboard. Top Widths Effective and Effective Flow Ineffective Flow Upstream face 980 ft 1013 ft' Downstream face 980 ft 1013 ft' ° includes bridge piers October 1992 Page 4 of 6 11-38 /kPPLIC. A'rK}N/CI~RTB~ICATIOI, i' ~ ~ CONDITIONAL Liii-l]:~l~ ~ MAP REVISION. Ltk~-I]~,t OF ~ RI{VISIO~I/th']) I:~-IYSICAL ~ RI~/ISION B~E/CLR.VERT FOI~VI Analysis (¢ont'd) Loss Coefficients Entrance loss coefficient N/A Manning's "n" value assigned to the structure(s) .040 dry swale/.035 deep swale/ .050 channel Friction loss coefficient through structure(s) N/A Other loss coefficients (e.g., bend, manhole, etc.) N/A Total loss coefficient Weir coefficient N/A Pier coefficient N/A Contraction loss coefficient .5 Expansion loss coefficient .7 Sediment Transport Considerations 1. A. Is there any indication from historical rex:or& that sediment transport (including scour and deposition) can affect the lO0-year water-surface elevations* [] Yes [] No B. Based on the conditions (such as geomorPhology, vegetative cover and development of the watershed and stream bed, and bank conditions), is there a potential for debris and sediment transport (including scour and deposition) to affect the 100-yeur water-surface elevations and/or conveyance capacity through the bridge/culvert? [] Yes [] No 2. If the answer to either lA or lB is yes: A. What is the estimated sediment ~ material) load? -- cfs (att_ach gradation curve) Explain method used to estimate the sediment transport and the depth of scour and/or deposition B. Will sediment accumulate anywhere through the bridge/culvert? [] Yes [] No If yes, explain what is the impact on the conveyance capacity through the bridge/culvert? October 1992 Page 5 of 6 11-39 AI~LICATION/Cl!RTI~ICATION FORblS FOR CONDITIONAL L~l-l~ OF MAP REVISION, Ligl-ll~t OF MAP REVISION AND PHYSICAL MAP I~VISION BRIDGE/CULVERT FORM Floodway Analysis Explain method of bridge encroachment (floodway run)Bridge encroachment defined by cross section geometry. Comments (explain any unusual situations): Attach Analysis October 1992 Page 6 of 6 ti-40 APPLICAT ION~R'I~IC-.A. TION PORMS I~OR CONDITIONAL L~-rl:l~ ON MAP RE'VISION. ~ 0~' MAP l~VISiON AND PHYSICAL MAP REVISION Appendix A - Appendix A _ Figures · .4?" '" / ':~ "~ ' "~'-- % ~ // ~ m Fork Filtratio- Plant "' -":: )[ ,~. ~ CITY OF' ~ ['~ .":: '~m CARROLLTON ' ::-'" Trail( SITE LOCATION --'.'-:?-',', :DALLAS COPPELL cn ," , 450 I BELT ',, LINE SCALE 1:24000 :-- 0 I ~!fLE __ 1000 C '.000 2000 3000 4000 5000 6000 7000 FEET I 5 0 !KILOMETER CONTOUR INTERVAL 10 FEET -- DOTTED LINES REPRESENT 5 FOOT CONTOURS NATIONAL GEODETIC VERTICAL DATUM OF 1929 ROAD CLASSIFICATION CARROLLTON, TEX. Heavy-duty .............. Light-duty NW/4 CARROLLTON 15' OUADI~ANGLE Medium-duty Unimproved dirt ......... -- ].959 O Interstate Route ~ U.S. Route 0 State Route DMA 6649 IV HW-SERIES V882 - FIGURE 1 LOCATION MAP · 15.07 · 12 DUPLICATE MODEL N-VALUES 47O I I I I I I I I I I I I I I I I I i I I I I I I I I I -- . 1 3 3 . 07( . 1 313 480 ~ , I -- - RE'/BASE ENCF iOACHMENT z~5o - I _ _ - I 1 ....... , I F- _ - I I:- I ~ t I ~ I - E UPLICATE FI S SECTION DUPLICATE FI~ _ ~ ENCROACHM[~NT _ -438.~8 LEFT ~ 437.09 RIGHT _ _410.00 ELMIN - 0 ~000 4000 8000 8000 ~ 0000 ~ ~000 ~ 4000 ~ 8000 5-z4-~9~4 SECT I ON 88 1 80 F~GURE 2A (~8~50) REVBASE. OAT .08 .075.06 DUPLICATE MODEL N-VALUES 460 I I I I I I I I I I I I I I I - .200 035 .035 - - .0§0 REVBASE - - I ~NT - - ;HMENT I - 45O 440 <~ 4DO LU N )N-EFFECTI~/E ' - AREA - LEI _ 420 4].0 - [~UPLICATE FIS SECTION_ _ )UPLICATE F,S _ _ ,NCROACHMENT - 400 409. go ELMIN ~)§0 I I I I I I I I I I I I I I I I I I I I I I I I 1 0 2000 4000 6000 8000 10000 12000 14000 16000 1800 ~ 5-2:3-1994 SECT I ON 89230 FIGURE 2B (89050) REVBASE. DAT · 08 .075 .06 DUPLICATE MODEL N-VALUES 47O O0 . lO .2 . 1 0 .045 REVB,q~SE ;HMENT - 480 REVB ;E _ 450 z ~ 440 NON-EFF FLO~V AREA 42O DLIPLICATE FIS SECTION DIlPLICATE. FIS - EI~ICROACHMEIqT _ 4].0 433.40 LEFT 441.00 RIGHT 410.67 ELMIN 400 I I I I I I I I ] I I I I I I I I I I I I I I I I I 0 2000 4000 6000 8000 1 oooo i 2ooo i 4000 i eooo i ~ 5-23-1994 SECT ION 90210 FIGURE 2C (90000) '=' REVBASE. BAT .08 .075 ,06 DUPLICATE MODEL N-VALUES 47O - .200 . 180 .;~ (;0~ .045 . 140 .045 - - REVBA~E ~ I .075 - -ENCROACl- MENT II I - 450 ~ . - I - 430 _ NON-EFFE(:TIVE FLOW AREA 42O - -- DU )LICATE FISSECTION - DL PLICATE FIS EN ~ROACHMEt IT 4~0 - 437. O0 LEFT 442.10 RIGHT _41~,60 ELMIN - 0 ~000 4000 6000 8000 ~O00D l~0OD 140OD 16ODD 1SOO( · 08 .075 .06 DUPLICATE MODEL N-VALUES 470 - . ~.0() . 100 20 i .045 . 100 075 - REVBASE I I ' - . ENCROAC:HMENT I I - 480 I ~ -- ~ -- __ REVBASf! ENCROAC~IMENT _ 440 \ -~- ~ !1 ~ NON.EFFECTIVE :LOW AREA / 420 "- -- DL 3LICATE FIS SECTION __ , DL PLICATE FIS - Ek CROACHMEI IT _ 4~0 -441.~0 LEFT i~,~ 443.00 RIGHT _ _410,19 ELNIN - o 2ooo 4000 6000 8000 z oooo z 2ooo 14000 5-23-1994 SECT I ON 92050 FIGURE 2E (9209.0) REVBASE. OAT 470 .07 .06 .06 DUPLICATE MODEL N-VALUES -~ .~120 . 035 .045 - _ - 200 .050 . 1201 ! 040 060 - - REVBA,~ ,E ' ' - __ --NCROACHI~ lENT t t REVI ~ASE ENCR(~ ACHMENT _ / - I I /× _ 450 43~ 42~ --- DU ~LICATE FIS SECTION DU 3LICATE FIS EN~ ;ROACHME~ 4~0 - 439. 00 LEFT ,~ - 441.70 RIGHT _414.50 ELMIN _ 400 I I I I I I I I I I I I II I I I I I I I I I I I I I D 20DO 4000 6000 8000 iD00D 120OD 140DO 16000 18DO[ 5-23-~gg4 REVBASE. DAT SECT I 0N 9~0 FIGURE 2F (93620) .07 .06 .10 DUPLICATE MODEL N-VALUES I I I I I I I I I ' I I II= _1 I I I I I I I I I I I I I I - .200.0!50 · 120 · 150 .040.'0:~3.045 - TOP OF.~§~ROLL'I'ON DAM 0 434 480 - REVB ~,SE ENCRO,~,CHMENT - 470 ~ /'~~ .... DUPLICATE FIS ~iECTION _ - NON_EFFECTIVE FLOW ~REA~ DUF'LICATE FIS _ .... ENC;ROAOHMEN' r _ 430 - 439. O0 LEFT 439.00 RIGHT _ _434.00 ELMIN - O 2DOD 4DOD 6000 8DOD 5-~3-~gg4 5E~T I ON 937 ~ 0 FIGURE 2G (93670) REVBASE. DAT · 07 .06 .10 DUPLICATE MODEL N-VALUES 470 I I I I I I I I I I I I I I I I I I I I I I I I I I I - .200 .200 . ogo . !50 . 040 . 060 - SANOY _AKE ROA[ BRIOGE . 045 460 REN'BASE ENCR 3ACHMENT Z C) ~ -- ~ _ 49O 42O - DI IPLICATE FI~ SECTION - DIJPLICATE FE - -- Et~CROACHME ~T 4ZO - 447, 49 LEFT /~ 447,85 RZGHT ~ _4Z4,50 ELN~N - ~ 0 ~000 4000 6000 8000 10000 1~000 14000 1~000 18uO[ 5-29- i 9~4 SECT I ON 93750 F~GURE 2H (9~7~0) REVBASE. OAT .07 .06 .07 DUPLICATE MODEL N-VALUES 470 I I I I I I I I I I I I I I I I I I I I I I I I I I I - so' LZNE 'C OSSZN' - RE~ BASE ENCR DACHMENT - 440 NO[ I-EFFECTIVE FLOW ARE.~ 420 - .___ DUP!_iCATE FIS ~ECTION - - ~ DUP _ICATE FIS - ENC ROACHMEN'~ 410 - 439. 60 LEFT , 438. 80 RIGHT _ 416.4;:) ELMIN _ 400 I I I I I I I I I I I I I I I I I I I I I I II I I 0 2000 4000 8000 8000 10000 12000 14000 16000 1800C 5-Z3-Z994 SECT I ON 93840 FIGURE 21 (93810) REVBASE. BAT .07 .06 .09 DUPLICATE MODEL N-VALUES 48O I I I I I I I I I I I I I I I I I I I I I I I I I I I -- . ! ! 0 . 07 ) . 040 . 045 - OENTON CREEK C(~NFLUENCE . OliO 470 4~0 · 450 440 ' ~,' _ _ _- 430 -/ _ NON-EF :ECTIVE FL(~W AREA DUPLICATE FIS SECTION - DUPLICATE FIS _ EN(~ROACHMEN T - 420 -444.90 LEFT ~ ~ _ 442.20 RIGHT _ _423.50 ELMIN - -2000 0 2000 4000 BO00 8000 10000 12000 14000 1BuO[ 5-2a-~gg4 SECT I ON g7710 RGU~E REVBASE. DAT .07 .06 .09 DUPLICATE MODEL N-VALUES 48O _ I I I I I I I I I I. 07010611t]0g01 I I ' i I I I I I I I I I I I _ 470 - REVBASE !NCROACH~'ENT 460 ~'~ ~, 450 -- ~ ~ - - I~ - _ - 430 t _ - t D JPLICATE FI~ SECTION - - DiIPLICATE FI~ - 420 EiiCROACHME 4T - 443, 05 LEFT 445,00 RIGHT _ _ 426, 00 ELHZN - 4~0 I I I I I I I I I I ~ ~ ~ ~ ~ I I I I I I I I I I I I -2000 0 2000 4000 6000 8000 ~0000 ~2000 14O00 5-23-t994 SECT ~ 0N 98460 FIGURE 2K (98450) REVBASE. OAT .07 .06.09 'DUPLICATE MODEL N-VALUES 48O I I I I I I I I I I I I I I I I I I I I I I I I I I I - . ( 700600g0 470 - REVE &SE ENCRO ~CHMENT - 460 > _ ~ I ~ _ Ld ! _ 4:B0 NON-EF :ECTIVE FL( lW Al:lEA - ~" DUF'LICATE FIS ~ECTION ~, __ DUF'LICATE FIS _ - ~ EN~.~ROACHMEN T - 4;'0 -444,.10 LEFT v~ 443.10 RIGHT _ _428.30 ELMIN - C -4000 -2000 o 2000 4000 6000 eooo ioooo i2ooo i 4uoc 5-23-1994 SECT I ON 99420 FIGURE 2L (99280) REVBASE. BAT 480 J~a3 .' ~, ; . 480 ~ w ~ w 0 0 ~ 0 0w ~ _.~__. ~ --- ~ 450 ........................ 450 0 - ~ 440 44o - 10-YEAR 43o- 50-YEAR , 430 420 ELM FORK - TRINITY ~VER SANDY L~E ROAD ~OPOSED CONDITION MODEL EXISTING ~N~SE J~E 29, 1994 400 400 88000 89000 90000 91~ 92000 930~ 94000 95000 96000 97~ 98000 99000 100~0 C~ WA~ ~A~ ~ DISTANCE IN FEET FIGURE 6 HALFF ~SSOCIATES / _ C/~RROLL ION'~:~ / APPROXIMATE SCALE ',,, 1000 0 1000 FEET \ LEGEND FLOOD INSURANCE RATE MAP CITY OF TEX~S DALLAS, DENTON ...... co~c,~m~o~os~ ~coor~w^¥ A~D ¢OLLII~ COUNTIES COMMUHITY-PANEL NUMBER 480167 0010 E REVISED FLOODPLAIN AND FLOODWAY FIGURE 7A Ii I HALFF ASSOCTATES FIRM -- ~ ~.,~ FLOOD INSURANCE RATE MAP : _~ ~ -~'" _ . s CITY OF : _ ~ _..? CARROLLTON, -~ '~'-" ' ~ : TEXAS o - -'-' 5 ~ '";' '~ x ~ "::~! ' !- © DALLAS, DENTON :_- - -'"' -' ,._ 5 AND COLLIN COUNTIES :. .'~ LLJ '~- ...... -/ -L~"~--/-'"'-----'~ /' ,,, " o< COMMUNITY-PAHEL NUMBER ' z LEGEND i' ' /1 ~ ~ . .- '~-' " - I ~ ~ : ~.' . N ~'--'--' '... ,,-- :~ . ~., .' . '....,. _- =-.'"' _ ZONEAE Basefl~i;levadomdelerm,ned- / ~ _ _ O.-~,,~._ ' "'--<' ' _ . '*'~ J~:- -~%" ;':.' ;'- 'i ~ FLOODWAY AREAS IN ZONE AE : ' X OTHER FLOOD AREAS ' ~ ~ ZONE X Areas of ~-year tlo~: areas of l~-vear flood with average depths of less than 1 f~t or I ~jl . .,:; '" ~': O with drainage areas less than 1 square m,le; "':'~ -'' -~;' · N and areas protected by levis from l~-year ~ '" N , _'--:'~ - flood. OTHER AREAS I ZONE X · &mas determined to be outs,de 5~ ~ear fh)(,d- plain I ' X - ~ ~-.~ ~ %., %. ·. -.. :':' ~ '-. . ~' ' -- CORRECTED / PROPOSED FLOODWAY -", '~. Z- .- ~ X w Z I .. .//..: . -~ ~ ( -',',,'', REVISED FLOODPLAIN -: ~ ~ -. ,.,,, _. }'~.~-..' ~--.;.~ , AND FLOODWAY I FIGURE 7B I [] "' I HALFF ~ssoc~T~s FIRM -- ..... ~CiTyFLOODoFINSURANCE RATE MAI) i ~ COPPELL, TEXAS ~, .. DALLAS AND DENTON COUNTIES o ~ ~1 COMMUNITY.pANEL NUMBER ~ x , ~ 480170 0010 E : -- ~ u ~:~ ~ . .,,,~;~":: ~ ~ MAP REVISED: ~PR~ 15, 1994 }q II l? ~ S[E(JI,M tLO()D HAZARD ,XRE,X5 [Nt ND&TED ~ RS l~t-~r*NR FLOOD  FLOOD~A~ AREASIN ZONE x[ ~ ~/- ~//' ~ ~//$ ~ ~' ~ ~.z ~ ~ , I I I I I , - , , ,, ,,,, ..... ,,,, ~' , ~, .... , ..... i ~~'~ , , I FIGURE 7C SSOOT T S FIRM FLOOD IItSURANCE RATE MAP CITY OF DALLAS, TEXAS DALLAS, DENTON, COLLIN, ROCKWALL AND KAUFMAN COUNTIES ,, COMMUNITY-PANEL NUMBER 480171 0020 D KEY TO MAP 500-~'ear F~ood Bour~darv - ZONE B lO0-1-ear Flood Boundary, - - ~ ,I (I/~/L ,~/ 1/x'/%/[ ? /,:'/1 / 1,' Ztn~' [)e,,ifznaht)n,* ZONE B % *EXPLANATION OF ZONE DESIGNATIONS EXPLANA FION ~ Om A'~ -A30 Areas of 100-¥.ear flood: bas,., flood ele,.,at~uns and tiood ha/ard  /./..¢~?.. fa{ lc, rs determined  ~ CORRECTION TO 100 - YEAR FLOODPLAIN  CORRECTED / PROPOSED FLOODWAY ~ REVISED FLOODPLAIN ^...o×,~^~ ~c^~ AND FLOODWAY 1000 0 1000 FEET (----tI f t t FIGURE 7D Z.i. ":~ '..."~! : ~/~;"' .... . .............. ' -- ,I ..................................... :.:>SCALE IN FEET ................. ?.? ......... ~ ......... ~,, ~ AREA TO +437.0 -'" 'C> 4:'?' ~ ....... 2. ~ P~P.~ED BY, m~EEWS- ,UWEYORI- saEms'm :3075 BR~C~I,4~IOGE BLVO. SUITE 415 PHOTOGRAPHY OBTAINED ON MAP COMRA~ WITH NATIQ4AL MAP ACCURACY STOS. AS DI~IGN ~ OILY. FELD COND(TK)NS MAY DICTATE CHANGES TO THE INOICATED FIGURE 8 SANDY LAKE ROAD SECTI SANDY LAKE RD. BRIDGE HYDRAULIC STUDY FORICHARLES GOdER & AssoaA'r~S, AND DALLAS COUNTY, TEXAS PROPOSED STATIONS FROM HYDRAULIC MODEL Appendix B - Appendix B - Revision Request Acknowledgements _ City of Carrollton City of Coppell DRAFT June , 1994 Federal Emergency Management Agency -- 1725 I. Street N. Washington, D.C. 20472 Attn: Mr. Alan Johnson Re: Request for Conditional Letter of Map Revision on the Elm Fork of the Trinity River - Sandy Lake Road Bridge Hydraulic Study Dear Mr. Johnson: _ We have reviewed the request for a Conditional Letter of Map Revision (CLOMR) dated June 1994, as prepared by Halff Associates, Inc. for Dallas County and the City of Dallas, Texas. The City of Coppell supports this request for modification of the 100 year flood plain and floodway _ for proposed improvements to Sandy Lake Road with downstream flood plain excavation within the Cities of Dallas and Carrollton. _ Yours very truly, City of Carrollton - Tim Tumulty, P.E. City Engineer - DRAFF June , 1994 -- Federal Emergency Management Agency 1725 I. Street N. Washington, D.C. 20472 Attn: Mr. Alan Johnson -- Re: Request for Conditional Letter of Map Revision on the Ell Fork of the Trinity River - Sandy Lake Road Bridge Hydraulic Study Dear Mr. Johnson: We have reviewed the request for a Conditional Letter of Map Revision (CLOMR) dated June 1994, as prepared by Halff Associates, Inc. for Dallas County and the City of Dallas, Texas. The _ City of Coppell supports this request for modification of the 100 year flood plain and floodway for proposed improvements to Sandy Lake Road with downstream flood plain excavation within the Cities of Dallas and Carrollton. Yours very truly, _ City of Coppell Ken Griffin, P.E. City Engineer Appendix C - Appendix C - Geotechnical Report GEOTECHNICAL INVESTIGATION SANDY LAKE ROAD BRIDGES OVER ELM FORK TRIBUTARY - DALI_AS, TEXAS REPORT NO. DE92-058 cHARLES GOJER & ASSOCIATES, INC. TERRA-MAR, INC. _ DALI.AS/I~ORT WORTH/HOUSTON JANUARY 1993 Consulting Engineers · Geotechnlcal · Environmental · Construction Materials Testing DALLAS · FORT V./ORTH a HOUSTON ~ January 28, 1993 Report No. DE92-058" Charles Gojer & Associates, Inc. 11615 Forest Central Drive Suite 204 Dallas, Texas 75243 ATTN: Mr. Charles Gojer _ GEOTECHNICAL INVESTIGATION SANDY LAKE ROAD BRIDGES OVER ELM FORK TRIBUTARY Gentlemen: - Transmitted herewith are the results of the geotechnical investigation performed at the referenced bridge sites. This report briefly describes the field and laboratory investigations together with recommended parameters for the design and construction of the bridges. _ This investigation was authorized by Mr. Charles Oojer on November 12, 1992. FIELD INVESTIGATION Subsurface conditions at the proposed bridge locations were evaluated by four sample borings. The locations of the test borings are shown on the Plan of Borings, Figure 1. The elevations and station reference numbers indicated on the boring logs were provided by - Albert H. Halff Associates, Inc. Cohesive soils were generally sampled using a thin-walled Shelby tube sampler, while -- _granular soils_were sampled with the split-barrel sampler in conjunction with the Standard Penetration Test (SPT). _ Borings B-1 and B-3 extended about 20 feet into the unweathered shale formation, while Borings B-2 and B4 penetrated the unweathered shale formation about 2 feet. Texas Department of Transportation (TxDOT) Standard Cone Penetrometer tests were performed at five foot intervals. These results are reported on the Boring Logs. - Additionally,. . the borings, were continuously cored, between the. TxDOT. cone penetrometer ~ntervals us,ng an NX-stze core barrel. Th,s allowed exam~nauon of the shale core for evaluation of the formation's uniformity and consistency. The recovery and rock quality _ designation (RQD) from each core run ~s reported on the Boring Logs. Sample depth, soil and rock description and soil classification (based on the Unified Soil Classification System) are shown on the Logs of Borings, Figures 2 through 8. A key to the - descriptive terms and symbols used on the logs is presented on Figure 9. 2679 Lombardy. Dallas, Texas 75220 Phone: 214-352-8352 SUBSURFACE CONDITIONS Geolo~v The seological formation exposed at the surface at the bridge sites is a Quarternary Alluwal (flood plain) deposit associated with the Trinity River. These depos~i~ gen. erally. consist of variably stratified clays, silts, sands and gravels. The particle sizes ot me m~uvim soils generally increase with depth. Underlying the alluvium is the Eagle Ford Shale Formation of Cretaceous age. The shale is darkgray in color and contains hard limestone stringers. The shale weathers to form rather deep clay deposits. However, at this site,, the weathered zQ. ne has generally b~.en ~ eroded away by the action of the river currents. An excemption to this was encounterecl at Boring B-3, where the highly active weathered shale stratum is pr~sent at a depth of about eight feet below existing grade. Site Subsurface Strati~aphy The detailed subsurface stratigraphy at each boring location is shown in detail on the attached Logs of Borings. Subsurface soils generally consist of alluvial soils, both fill and natural, underlain by the Eagle-Ford Shale formation. Fill soils were encountered to depths ranging from about 1.5 to 13 feet below existing grade. The fill material at the site consists of clay, sandy to very sandy clay and sand layers with varying amounts of silt, gravel, rock and asphalt. The clay fill soils are stiff to hard in consistency with hand penetrometer readings ranging from 1.2.5 tons per square foot (tsf) to in excess of 4.5 tsL The granular fill soils are generally medium dense. The natural soils are alluvial deposits consisting of very soft to very stiff clay to very sandy day soils and medium dense to loose sands with varying amounts of day, silt and gravel. The dark gray unweathered Eagle Ford Shale Formation was-encountered at depths ranging from 13 to 39 feet below existing grade, E1 404 to El 431. Oroundwater Level Observations Short term and long term ground water observations were made at each boring location as reported on the Boring Logs. The groundwater levels at the time of this investigation ranged from about E1 429 to El 436. It should be recognized that groundwater conditions will fluctuate with seasonal precipitation, surficial runoff and water levels within the existing Elm Fork Tributary. LABORATORY INVESTIGATION The laboratory testing program was directed primarily toward evaluation of physical and engineering clmracteristics of the underlying soil and shale strata. Identification tests consisted of liquid and plastic limits, natural moisture contents, sieve analyses and unit dry weights. These test results are tabulated at the appropriate sample depth on the Boring LOgs. Results of sieve analyses are presented on Figure 10. Shear strengths of the clay soils, evaluated by hand penetrometer tests and confirmed by laboratory unconfined compression tests, are also shown on the Boring Logs. Strength of the underlying shale was evaluated by means of TxDOT cone penetration tests, and (J:\DEREPORT~ DE92058.DOC) 2 confirmed with unconfined compression tests. Test results are shown at the appropriate depths on the Boring Logs. Absorption pressure swell tests were run on a sample of the near surface overburden clay soils and the deeper severely weathered shale stratum to determine their swell potential - characteristics when exposed to additional moisture. In this test, the sample is placed in a one dimensional consolidometer, and restrained under existing overburden pressure...The samPle is then inundated, and the restraining pressure is i.ncreased to Prevent swe!h.ng. - The maximum swelling pressure generated by the samp!e.~s record..ed: Toh.e. restraLn.~ng pressure is then reducedto the overburden pressure and the .magmtuae o~ me r~ult~n.g vertical swell is measured. These test results are presented ~n the form of logarithmic _ pressure-swell graphs on Figure 11. RF~OMMENDATIONS -- Design Requirements It is our understanding that the final alignments have not been established to date. - However, it is proposed that the interior bents and abutments will be supported on drilled straight shaft piers, penetrating the underlying unweathered, moderately hard shale stratum. It is understood that foundation loads for the main bridge will be on the order of about 250 to 300 tons while lOads for the relief opening bridge will be on the order of about - 150 to 200 tons. The bridge spans are anticipated to range from about 80 to 120 feet. Pier Foundations It is recommended that the bridge structures be supported by means of straight shaft pie~ founded in the moderately hard dark gray unweathered shale stratum. Elevations anci _ depths below existinggrade to the unweathered shale bearing stratum encountered in Borings B-! through B-4 are presented below: Boring Depth to Elevation at - No. Top of UW* Shale Top of UW* Shale B-1 23' 424 B-2 39' 404 B-3 19' 423 B-4 13' 431 - * Unweathered _ Note: Depth in feet measured from existing grade. Actual pier depths during construction will depend upon depth of fill required for roadway embankement construction and design penetrations into bearing stratum. - It should be recognized that scour within the creek bed may have deepened the top of the shale stratum between Borings B-1 and B-2. The axial capacity of the piers supporting the abutments and bents was based on unconfined compression tests, TxDOT Standard Cone - Penetrometer tests and methods outlined in the Texas State Department of Highways and (J:\DEREPORT~DE92058.DOC) 3- ~ Public Transportation Bridge Division Manual entitled Foundation Analysis, Exploration and Design Manual. Foundation Design Parameters Depth to Bearing Stratum: 13 to 39 feet below existing grade at the boring .locations, El 404 to El 431. Description of Bearing Stratum: Moderately hard dark gray unweathered shale. Allowable End Bearing: Fifteen (15) tons per square foot (tsf) for minimum seven (7) foot pier penetrations into bearing stratum. Allowable Skin Friction - Compression Loads: Two (2.0) tsf for pier penetrations into bearing stratum in excess of three (3) feet. Pier penetrations in excess of seven (7) feet may be designed for a skin friction value of two and 0ne-half (2.5) tsf. Allowable Skin Friction - Tension Loads: One and one-half (1.5) tsf for pier penetrations into bearing stratum in excess of three (3) feet. Allowable Lateral Loads: See Appendix A. Minimum Pier Penetration Into Bearing Stratum: Pier penetrations into bearing stratum should be minimum of seven (7) feet. During pier design, the upper three (3) feet of penetration into bearing stratum should not be counted on for skin friction load transfer. All pier penetrations into unweathered shale bearing stratum should be measured from the bottom of the casing. Casing Requirements: All pier installations will require the use of temporary caSing to seal out ground water and caving soils during concrete placement. All casings should be seated below the surface of the unweathered shale bearing stratum. All pier penetrations should be measured from the bottom of the easing. That portion 'of the shale, through which the casing is set, should not be counted on for the required pier penetration during field installations. General Foundation Design and Construction Criteria 1. All pier foundations should be provided with sufficient tensile steel reinforcement to resist uplift forces generated by the swellinig clay soils. It should be assumed that the upper 10 feet of each pier shaft supporting the interior bents is subjected to an average uplift force of 1,500 psL It should be assumed that the upper t5feet of each pier shaft supporting the abutments is subjected to an average uplift force of 1,500 psL 2. Recommendations regarding embankment construction and slope stability were not within the scope of this investigation. However, in order to minimize uplift forces on the pier shafts and in order to reduce differential movement between the bridge (J:\DEREPORT~DE92058.DOC) 4 structure and the approach sla_bs, all clay fill soils shoul.d be compacted in maximum - eight inch lifts at optimum to tour percentage points above optimum moisture to a compaction level ranging from.95% to 100°~ Standard Proctor density. All sand fill soils should be compacted at plus to minus three percent ot optimum moisture to a - minimum of 95% Standard Proctor density. 3. For cluster piers, where the Clear spacing between piers will be less than 3 pier diameters (3D), a reduction factor should be applied to the allowable skin friction - for the determination of required pier penetrations. · For piers touching (clear spacing is zero), a reduction factor of 50% should be used. For a clear sPacing of 3D, where D is the diameter of the largest adjacent pier, no reduction is necessary. - A straight line interpolated reduction should be used where the clear spacing is between zero and 3D. _ 4. A minimum 8 inch void space should be provided beneath any pier supported grade beams, strap beams, wing walls or abutments. 5. All piers should be concreted within 8 hours of penetrating the unweathered shale - bearing strata. All concrete for the pier foundations should be placed using a tremie in order to limit the free fall of the concrete to about 5 feet; The installation of these piers should be inspected to verify that proper procedures are used. 6. All.piers will require the use of temporary casin, g to seal out ground water and caving soils during concrete placement. All casings should be seated below the _ surface of the dark gray shale bearing stratum. All piers should be inspected to assure that proper easing procedures are used, that a sufficient head of fluid c.oncrete is maintained within the easing at all times during extraction, and that all pier holes are properly cleaned and reasonably dry prior to concrete placement. 7. Due to the need for temporary casings at the bridge site, and in order to achieve' positive adhesion between the pier shafts and the shale bearing stratum, fluid - concrete having a slump of five to six inches should be used. A concrete mix design should be used that will provide the designed concrete strength using a seven inch slump (to provide a reasonable tolerance during construction). - Active Soil Pressure Lateral Soil Pressure Against Bridge Beams and Wing Walls Backfill material placed adjacent to bridge beams, abutments and wing walls should consist of clayey sand or sandy clay having a plasticity index (PI) between 4 to 12 in order to limit _ the at-rest lateral soil pressure against the beams to 60 per (equivalent fluid pressure assumes fully drained conditions). Select backfill should be placed in a wedge extending from the base of the structure to the ground surface along a 1 to 1 slope. Backfill should be [~laeed in maximum 8 inch lifts and compacted to between 95% and 100% Standard - t'roctor density. Compaction within 5 feet of the structures should be achieved using hand compaction equipment. Measures should be taken to allow for drainage of the backfill. One method would be to place a minimum of 12 inches of free draining sand or gravel _ behind the wall. A perforated pipe, wrapped with a suitable filter fabric, could then be placed near the base of the wall to provide continuous drainage of the backfill. If measures are not taken to allow for drainage of the backfill, an at-rest lateral pressure of 90 I~cf should be used (equivalent fluid pressure assumes undrained conditions and a full - hydrostatic head). Traffic live loads and surcharge loads should also be included in the design of any below grade wall. (J:\ DEREPOR'I~DE92058.DOC) 5 LIMITATIONS The recommendations presented in this report are based on a discrete number of soil test boring. Although our field personnel visually survey the site for surface features indicative of variable soil conditions, subsurface conditions may be encountered that differ from these data. In this case, our office should be notified immediately so that the effects of these conditions on design and construction can be addressed. This study was conducted for the exclusive use of Charles Gojer and Associates, Inc. The reproduction of this report or any part thereof, in plans or other documents supplied to persons-other than the owner, should bear language indicating that the intormation contained therein is for general design purposes. All contractors referring to this geotechnical report should draw their own conclusions for bidding purposes. We appreciate the opportunity to assist on this project and trust that our recommendations will lead to cOSt effective construction. Please call us if we can be of further assistance. Sincerely, TERRA-MAR, INC. Nasir H. Syed Mark J. Farrow, P.E. Staff Engineer Vice President Copies submitted: (3) (J:\DEREPORT~DE92058.DOC) 6' - ,~ , i FIGURE LOG OF BORING BORING B-1 Borzng: B-! Date: ~-~2-93 Pro,ecL No: DE92-058 Project' Sandy Lake Road Bridge over E]B Fork Tributary - Pal]as. Texas E]ev: 447.1 Location: N 48373.5~992. E 14461.8878~ (See Figure Depth to water at completion of boring: &&.4' Depth to water ~hen checked: ¢ 24 Hours ~as: &0.8' Depth to caving ~hen checked: ~ 24 Hours ~as: ~5.3' ELEV SOIL SYM~LS MC LL ~ PI -200 D.D. P. PEN. U~ON. SAMPLERSYMBOLS DESCRIPTION ~PTH S FIELD TEST DATA 450-I ~ _ · ~ - ~e'd~u'm"de~se'b'~'h"~"gFay's~'~' ~.5 · 'O_ ~.~... ';~ GRAVEL ~ -brown sandy s~Zty c~ay 445- ;~. 5/6 -8/6 -yellowish brown clay ~,5'-4.5" t/6 [FILL) (SP-GP) 0.75  trace gravel ~ sandy clay layers -to ~ -becomSng dark gray below lO' 2.5 4a5- i I (FILL) '(CL-CH) - some f&ne to med&um gravel -ts l~a/e - some sandy gravel layers 430 - I~ ; -  (SC-GP) -20 ~e/e - ve'r~ ~ tO/6 ~6/6 sand seams ~ pockets 425- (CL-CH) ~_~ - ~0de. r.ate, iy..har.d.d.ar~..gray .... ~--~ unweathered SHALE ---- -w/ fractured tan weathered 50/2.5 bands to 26' ~8 ~6 ~3.ee Core Run #~: 25.0'-30,0' 4~o-- / Recovery: 30%~ Boring RQD: 30%~ Continues Water Checked @ ~4 Hours Comp]etlon Depth: 45.0' ~ Core Loss Due to Mechanical Breakage / Blockage ~th~n Core Barrel FZGURE NO: 2 TERRA-MAR, INC. LOG OF BORING BORING B-i Borzng: B-1 Date: ~-~2-93 Pro)ect No: DE92-058 Pro~ect: Sandy Lake Road Bridge over E]m Fork Tributary - Dallas, Texas Elev' 447.1 Location: N 48373.5~992, E 14461.8878~ (See Figure Depth to water a~ completion of boring' ii.4' Depth to water when checked: ~ 24 Hours was' i0.8' Depth to.caving when checked: ~ 24 Hours was: 15.3' ELEV SOIL SYMBOLS MC LL PL PI -200 D.D. P. PEN. UNCON. SAHPLER SYMBOLS DESCRIPTION DEPTH ~ FIELD TEST DA3A % % % % Pcf tsf tsf 420- /~ -- ~ --~o ~ 5oz~.~- ~40'0~r'at'e'iy'"h~'d"0'a~"~'r'a9 ........... -------- 507t O0 ~7 ti7 ~5.53 ---- unweathered SHALE, ~_~ calcareous w/ thin limestone -- 4~5- - __~,-: str ~ngers ---- Core Run #2: 30.0'-35.0' ~,-~ Recovery: 93% -- , 50/0.75 __ . 15 11~1 37.~1 4~o-- ~,.~ Core Run #3: 35.0'-40 0' -- __--_- Recovery: 93% ~ ~_.___ RQD: 93% -- -- 50/0.~5 --40 --__--_ 50/O.L:~ ~4 tt7 69.3g ~,~ Core Run #3: 40.0'-45.0' RQD: ~g%~ Comp]e~ion Oeptn' 45.0' ~ Core Loss Due ~o Hechan~ca~ Breakage / B}ockage w~th~n Core Barre~ -- FIGURE NO: TERRA-MAR. INC. LOG OF BORING BORING B-2 Borzng: B-2 Date: ~-12-93 Pro)act No: DE92-058 Project: Sandy Lake RoaO Brsdge over Elm Fork TrSbu~ary - Dal2as, Texas E2ev: 442.6 Location: N 48449.95485, E 14950.03958 (See Figure Depth to water at completion of boring: 15.6' Depth to water when checked: © 24 Hours was: 13.8' Depth to caving when checked' @ 24 Hours was: 24.7' ELEV SOIL SYNaOLS HC LL ~ P! -aO0; O.O !P. PEN. U~ON. SANPLERSYNBOLS DESCRIPTION ~PTH ~ FIELD TEST DATA 445 -- -° ~ ~ - ve.r~..S~i.~...~6..S~iy~..~F6~n..~L.A¥ .... ~.~ L : ~ w/ sandy c~ay inc]usions. ~race  ~ f~ne SOHO. roc~ fragments, 44o- ~ gravel ~ asphalt fragments, a.0  ~ ~.7~ 2.75 -5 ~ -3" gravelly san~ layer ~ / -organics ~ 5.5' a.5++ 435- / (FILL) (CL-CH) -lo ~ ~ stains ~ sandy clay layers / 430 - ? I -becoming soft below 14' 3~ 54 20 34 0.5 (~2 ~1 ~.o 4~5 -- (CL-CH) ~/~1.:: -~Of~'~'bFO'W~"V~F~' s'a~d~"CE~Y"W? ...... -20 -- sand seams 0.5 42o - ~i= (CL) -~5 ~/!i 0.75 4~5- Bor~ng Continues Water C~ecked @ 24 Hours Comp]e(~on Bept~' ~.0' FIGURE NO: 4 TERRA-MAR, INC. LOG OF BORING BORING B-2 Bor~ng'B-2 Date' ~-~2-93 Pro)ect No: DE92-058 Pro~ect: Sandy Lake Road 8ridge over Elm Fork Tributary - Dallas, Texas Elev: 442.6 Location: N 48449.95485, E ~4950.03958 (See Figure Depth to water at completion of bDt&rig' 15.6' Depth to water when. checked: ~ 24 Hours was: 13.8' Depth to cay&rig when checked: ~ 24 Hours was' 24.7' ELEV I SOIL SYM~L$ MC LL ~ PI -200 O.D.P. PEN. U~ON. SAMPLERSYMBOLS DESCRIPTION ~ ~ ~ ~ ~c~ ~PTH I S FZELD TEST DAIA -- -3o i medium SAND w/ c)ay pkts. (SP-SC) 2Y6 4/6 Iorgan~¢ layers, sand seams ¢ _ 4~0- //- sandy clay layers i~1// (CL-CH) 14/6 -- 15/6 CLAY ~ fine SAND w/ weathered , shale fragments 405- (CL-CH) ----~45/6 unweathered SHALE, slightly -40 ~_~5o/4 calcareous w/ thin limestone -- --~'-~994~-~ str~ngers -fractured tan weathered seams to 4~' -- Comp]e(ion Dept~: 42.0' FIGURE NO: 5 TERRA-MAR, INC. LOG OF BORING BORTNG B-3 Borzng: B-3 Date: ~-~2-93 Pro]act No: DE92-058 Project: Sandy Lake Road Bridge over Elm Fork Tr~bu(ary - Dallas, Texas Elev' 442.1 Location: N 48350.73261, E 15443.94220 (See Figure Depth to water at completion of boring: g.8' (Backfill. ed) Depth to water when checked: N/A was' N/A Depth to caving when checked' N/A was: N/A !ELEV SOIL SYMBOLS SAMPLER SYMBOLS DESCRIPTION MC LL PL PI -200 D.D. P. PEN. UNCON. DEPTH C FIELD TEST DATA % ~ ~ X pcf tsf tsf 445- ! 440 - - 6/6  li/s (FILL) (SC) w/ shell ~ gr. frags. (FILL] (CH] !:: ::i,:::: SAND w/ trace gravel 435-- :: :: :: --W/ light brown clayey sand · ~.~.~ ~ 5'-6' (FILL) (SH-SC) ~: weathered SHALE w/ si]t ~; sand -1o (~);~--~-~- pockets, severely fractured w/ Z--/~-[ ~ron stained seams 3.5 .~-~: -w/ shell fragments ~0'-12' 24 67 25 42 t00 4.5 I -2o ---- ~50/2.00 ca]careous w/ thin ]imestone ~8 lid ~4.~2 -- =~ 50/2.5o unweathered SHALE, slightly ~.~ str~ngers 420-- ~.~ -fractured tan weathered seams '~-~ to 2~' --~-~ Core Run #~: 20.0'-25,0' ~.--_ Recovery: 95% - -~5 ----_/5o/0.~8 RQD: 95% 50/0.50 ~B its J5.69 4~5-- / Core Run #2: P5 0'-30 O' Boring ' ' Continues Recovery: 98% RQD: 98% Complet &on Depth' 40.0' ~ Core Loss Due to Mechanical Breakage / 81ockage ~thin Core Barrel FIGURE NO: 6 TERRA-MAR. INC. LOG OF BORING BORING B-3 Boring: B-3 Date: ~-~2-93 Project No: DE92-058 Project: Sandy Lake Road Bridge over Elm Fork Tr~bu(ary - Dallas, Texas Elev: 442.1 Location' N 48350.73~61, E 15443.94220 (See Figure ~) Depth to water at completion of boning: 9.B' (Backfii]ed) Depth to water when checked' N/A was: N/A Depth to caving when checked' N/A was: N/A ELEV SOIL SYMBOLS MC LL PL PI -200 D.D. !P. PEN. UNCON. SAMPLER SYMBOLS DESCRZPTION ~ % X ~ )cf tsf tsf DEPTH & FIELD TEST DATA 4 ~5 -"~ / "-----"____.~__~.____~ ' - - 30 -- -- ~ 5oz0. r~ ~-~ 5070.50 ~7 ~.~.7 :~5.4 ! -- 4~o-- ~=~ Core Run #3: 30.0'-35.0' __~-~ Recovery: 94% ~-_- ROD: 93% -- - -~§ ~.~ 5o/o.5o ~.-~ 50/0.50 ~7 ~8 ~5.o9 --__--_ CoPe Run #4: 35.0''40.0' -- -- Recovery: 87%~ 405- - -- -- ~-~ RQD: 87% -- ~ i ~"~- 50/0.50 - ,40 -- --- 5070.50 Comp]et &on Depth: 40.0' ~ Core Loss Due to Mechanical Breakage / Blockage w~th~n Core Barrel FIGURE NO: 7 TERRA-MAR. INC. LOG OF BORING BORING B-4 Boring: B-4 Date: ~-~2-93 Pro]act No: DE92-058 Project: Sandy Lake Road Bridge over Elm Fork Tributary - Dallas. Texas Elev' 444.1 Location' N 48317.39093, E 16028.37242 (See Figure Depth to water at completion o¢ boning: Dry Depth to water when checked: ~ 24 Hours was' Caved ~ ~' Depth to caving when checked: ~ 24 Hours was: ii.O' ELEV SOIL SYM~LS MC LC ~ PI -200 D.D. P PEN. U~ON. SAMPLER SYMBOLS DESCRIPTION ' ~PTH & FIELD TEST OA~A ~ [ X ~ Dcf tsf tsf 445 -- --o gravel ~ rock frags.(FlLL) (CL) 8.5 - Lo.o§e..Fe.d~i.s~..bFo.~.~.a~e.y..~.~e.. SAND w/ trace gravel ~ orgs. (SC) 3.75 ......... - UO.o~e..~.d~i.S~..(~..~.~H~...S~Nb; ........ ~.~ 440 -- ' ......... 4/6 slightZy clayey --s 4/6 -decrease in clay content ::::::::: be low 4' ::: ::: ::: (SP) 435 -- ' ......... ~ - ~e'd~Jm"~'~s'e"~'a~"f¥~"~"c~a'r~e'- - - tO ......... ]g/6 7 ~i4/S SAND w/ some f~ne gravel ~ trace ~ ~ia/s coarse gravel ~ clay ::: ..... : ~j~o/~.oo-~O-d~Fa~e-i~..h~-d.-d.~h.~.-g-r~y ............. _ 50/8.00 unweathered SHALE, slightly 430 - --'~ 5o/o.~ calcareous w/ thin limestone - 15 -- --- 50/0.~5 stringers Completion Depth: ~5.0' FIGURE NO: 8 TERRA-MAR, INC. Legend: Symbol: Oescription: Symbol: Oescription'  SAND ~ GRAVEL ~ CLAY  Clayey SAND ~ SHALE _ ~ Sandy CLAY ~ SAND  Silty SAND ~ Severely Weathered SHALE  --~7/6 Standard penetration ~ Rock Core Sample. 5/6 test. N blows for -- 12 inches.  --~ Undisturbed thin ~--~ Bulk sample taken _ wall Shelby tube from auger flights.  --~ THO Cone Pone- F-~ Nater measured at _ trometer. 100 blows 'II time indicated for N.inches. ------ .[-----q Depth at which -- ~L completion of boring boring caved NOteS: i.Exploratory borings were drilled on dates indicated using truck mounted drilling equipment -- 2. Water level observations are noted on boring logs. 3.Results of tests conducted on samples recovered are reported on the boring logs. Abbreviations used are' -- OD = Natural Dry Density (pcf) LL = Liquid Limit (%) NC = Natural Woisture Content (%) PL = Plastic Limit (%) Uncon.= Unconfined Compression (tsf) PI = Plasticity Index P. Pen.= Pocket Penetrometer (tsf) -200 = Percent Passing ~200 4. Rock Cores Recovery = sum of core sample recovered divided by length of run. expressed as percentage. RQD = (Rock Quality Designation) sum of core -- sample recovery 4" or greater in length divided by the run. expressed as percentage. -- Project No. DE92-058 FIGURE NO: 9 TERRA-MAR, INC. .~.? GRAIN SIZE DISTRIBUTION TEST REPORT ~ ~- ~ ~ ~'~ ~"' o o o o 100 ~ ~ ~'- ~ ~-~ ~ ~ ~ ~00 ~00 ~0.0 ~.0 O. 5 0.0 . o~+ ~.o ~.o  LL PI DB5 D60 DSO 030 015 JJ 9.23 0.94 0.5~ 0.299 0.2~30. ~834 0.51 5. I MATERZAL OESCRZPTZON USCS AASHTO · Ten f&ne to coamse SAND ~/ some f&ne gr8veZ SP Project: Sandy Lake Rd. Bridge L. · Locab&on: Bor~ng 8-4, ~0'-~1.5' Date: 1-26-93 GRAIN SIZE OTSTRTBUTION TEST REPORT TERRA-MAR. INC. ~'ig~,~ No. ~0 Absorption Pressure Swell Test Test No ..................... 1((5)) 2(Fl ) Boring No ................... B-3 B-3 Depth (ft) ................... 3-5 11-12 Unit Dry Weight (pcf) .......... 99.2 100.7 Initial Moisture Content (%) ........ 23.2 24.4 Final Moisture Content (%) ........ 29.3 27.1 Maximum Swell Pressure (ksf) ...... 10.0 6.0 Vertical Swell (%) .............. 6.89 2.62 Final Swell Pressure (Overburden)(ksf) . 0.50 1.38 Liquid Limit (%) ............... 65 67 Plasticity Index (PI) ....... - ...... 40 42 Initial Penetrometer Reading (tsf) .... 4.5+ 4.5 Final Penetrometer Reading (tsf) ...... 2.0 2.5 12.0 10.0 _ v 8.0 o 6.0 _ '~ 4.0 2.0 o.o [ i ! 0.1 1.0 10.0 Restraining Swell Pressure (ksf) I| V ~* FIGURE 11 APPENDIX A LATERAL EARTH PRESSURE DESIGN CRITERIA Lateral forces on the pier shafts may be resisted by the upper soil layers and the underlying shale formation using the parameters outlined below. interior .B. ents: Neglect passive resistance (lateral pier support) to depth of six feet below o.west, adjacent final grade (6 feet below anticipated scour .depth) due to anticipated loss of ateral support caused by seasonal desiccation and ground shrinkage. Abutments: Neglect passive resistance to depth of seven feet below top of adjacent embankment slope or to depth of three feet below top. of pier shaft, whichever is deeper. Passive resistance may be counted on in the deeper soft la~ers provided these lateral forces are considered in the computation of driving forces dunng slope stability studies. This would not be necessary if passive resistance is not counted on within the zone of the sloped embankment. Allowable Passive Resistance: 100 psf per foot of depth for that portion of the pier shaft in direct contact with upper soil layers. A maximum value of 1,500 psf should not be exceeded in the soil layers (clay and sand). Passive resistance should be neglected along upper portion of the pier shafts as indicated above. Pier penetrations in excess of l~SD into the moderately hard dark gray unweathered shale stratum (where D is the pier diameter) may utilize .a constant uniform passive resistance of 20,000 psf for that portion of the pier shaft in direct contact with the dark gray shale. Only that portion of the pier penetration into the dark gray shale in excess of 1.5D may utilize this higher lateral resistance value. Due to the requirement that the pier shafts be socketed several feet into shale for axial support, the bottom of the pier shafts will be fixed and will not be free to deflect laterally. It should therefore be assumed that the point of contraflexure is 2 feet below the surface of the unweathered shale stratum. If calculations indicate that the lateral forces on the pier shafts are resisted entirely by the clay and sand strata (above the unweathered shale bearing stratum), the point of contraflexure can be assumed to be located at the depth in which all lateral forces are resisted. Recommendations regarding embankment construction and slope stability were not within the scope of this investigation. However, proper compaction of the embankment soils is essential in order to develop passive resistance (lateral pier support) within the embankment. Appendix D - Appendix D - FIS Exist. Conditions (multi-profile) - HEC-2 Model (Replication- SHELREV2) ********************************************* * U.S. A,V. MY COI~.PS OF ENGENEERS * * HEC-2 WATER SURFACE PROFILES * * HYDROLOGIC ENGINEERING CENTER * * 609 SECOND ST~EET~ SUITE D * * Version 4.6.2; May 1991 * * DAVISw CALIFORNIA 95616-4687 * * * * (916) 756-1104 * * RUN DATE 23JUN94 TIME 16=39:37 * ************************************* X X XXXXXXX XXXXX XXXXX X X X X X X X X X X X X XXXXXXX XXXX X XXXXX XXXXX X X X X X X X X X X X X X XXXXXXX XXXXX XXXXXXX 1 PAGE 1 23JUN94 16: 39:37 THIS RUN EXECUTED 23JUN94 16=39=37 ************************************* MEC-2 WATER SURFACE PROFILES Version 4.6.2; May 1991 ************************************* T1 U.S. ARMY CORPS OF ENGINEERS - FORT WORTH DISTRICT T2 UPPER TRINITY ~ECON STUDY *ELM FORK TRINITY P~VER* EXISTING CONDITIONS T3 ** 10 YEA~****** DISCHARGES: 2-YR 5-Y~ 10-YR25-YR 50-Y~ 100-Y~SPF T4 AHHA 2/94 FILE En~LREV2 ~ SHORT VER~ION STARTS ~ XSECT 85000 J1 ICHECK INQ NINV IDIR STRT METRIC HVINS Q WS~L FQ -1 4 0.00000 435.81 J2 NPROF IPLOT PRFVS XSECV XSECH FN ~T~.r~ IEW CHNIM ITEACE i -1 NC 0.070 0.070 0.040 0.1 0.3 QT 7 7300 15900 22400 29600 36500 44200. 84300 NH 8 .05 1320 .05 2260 .10 2325 .075 2625 .10 NH 2900 .05 3000 .08 4762 .035 5199 X1 85000 32 2325 2625 350 200 250 G~ 438 880 438 1080 426.5 1200 436 1320 436 2125 GR 438 2260 439 2325 430 2350 412 2390 412 2450 GR 421 -2470 430 2540 432 2555 434 2575 436 2590 GR 438 '2610 439 2625 438 2900 437.4 3000 436.5 3500 G!~ 436 3650 436 4000 435.6 4200 436 4500 436 4762 GR 425.7 4803 424.3 4944 424.3 4956 425.7 5109 433.8 5145 GR 435 5168 446.6 5199 NH 7. 0.050 4430. 0.10 4740. 0.06 4997. 0.10 5042. 0.08 NE 5782. 0.05 6071. 0.035 7513. X1 86560 62 4740. 4997. 1200. 900. 1560. X3 2000. 7100. GR 442.3 1000. 442.3 1998. 438.2 2023. 438. 2080. 436. 2100. GR 434. 2110. 432. 2130. 432. 2160. 430. 2170. 428. 2185. GR 427. 2210. 428. 2233. 430. 2245. 432. 2260. 434. 2270. GR 434 2300 430 2316 430 2776 436 2800 460 2821 GR 460. 4430. 438. 4440. 436. 4740. 434. 4765. 432. 4780. GR 430. 4790. 428. 4800. 410. 4875. 410. 4905. 428. 4980. GR 430. 4990. 438. 4997. 439. 5042. 437.8 5235. 438. 5280. GR 436. 5286. 436. 5292. 436. 5311. 436. 5317. 438. 5345. GR 438. 5354. 438. 5386. 436. 5400. 438. 5447. 439.1 5509. GR 438. 5564. 436. 5584. 436. 5603. 435.3 5696. 435.5 5782. GR 435.2 6071. 425.9 6108. 424.5 6250. 424.5 6262. 426. 6402. GR 428. 6580. 429. 7285. 430. 7304. 435. 7322. 436. 7352. GR 442. 7373. 442.1 7513. I PAGE 2 23JUN94 16:39:37 -- NH 5. 0.05 4895. 0.10 4953. 0.06 5110. 0.10 5200. 0.05 NH 7712. QT 7 7500 17300 24400 32500 39900 48600 91200 X1 87530 61 4953. 5110. 600. 1035. 970. X3 0 0 0 2000 0 7620 _ Appendix E _ FIS Exist. Conditions Floodway _ HEC-2 Model (Replication- SHFDWY-2) _ Appendix F _ Corrected Exist. Conditions (multi-profile) HEC-2 Model (REVBASE) - Appendix G - Corrected Exist. Conditions Floodway - HEC-2 Model (RVEXFDW2) _ Appendix H _ Proposed Conditions (multi-profile) HEC-2 Model (SHELPRO) - Appendix I _ Proposed Conditions Floodway _ HEC-2 Model (PROPFDWY)