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FIRM-931206ti��Y MAN Federal Emergency Management Agency w` ®f Washington, D.C. 20472 Mr. Kenneth M. Griffin, P.E. City Engineer City of Coppell P.O. Box 478 Coppell, Texas 75019 Dear Mr. Griffin: December 6, 1993 IN REPLY REFER TO: Case No.: 94- 06 -050R Community: City of Coppell, Texas Community No.: 480170 316 -ACK This is in response to your request, dated November 22, 1993, for a Conditional Letter of Map Revision (CLOMR) to the Flood Insurance Rate Map (FIRM) and /or Flood Boundary and Floodway Map (FBFM) for the above- referenced community. Pertinent information about the request is listed below. Identifier: Flooding Source: FIRM Panel Affected: FBFM Panel(s) Affected: Cambridge Manor Estates Denton Creek 480170 0010 D N/A On October 1, 1992, the Federal Emergency Management Agency (FEMA) implemented the use of forms for requesting revisions or amendments to National Flood Insurance Program (NFIP) maps for two reasons. First, because the forms provide a step -by -step process for requesters to follow and are comprehensive, requesters are assured of providing all of the necessary information to support their requests without having to go through an iterative process of providing additional information in a piecemeal fashion. Experience has shown this to be a time - consuming and cost - intensive process. Second, because use of the forms assures that the requesters' submissions are complete and more logically structured, FEMA can complete its review in a shorter timeframe and at a lesser cost to the requester. While completion of the forms may appear to, be burdensome, we believe it is prudent to do so because of the advantages that result for the requester. Please note that the NFIP is non - taxpayer funded and its expenses are paid for by policyholders. Therefore, to minimize the financial burden on the policyholders while maintaining the NFIP as self- sustaining, FEMA has implemented a procedure: to recover costs associated with reviewing and processing requests for conditional modifications to published flood information and maps. The initial fee of $640 is the minimum charge associated with our review of a request of this type. You will be notified of the estimated costs if we anticipate that, due to the extent of the review required, the total costs will exceed $3,500. In that situation, our review 2 would be suspended pending our receipt of written authorization from you to proceed. Using the previously referenced certification forms, we have completed an inventory of the items that you submitted. The items identified below are required before we can begin a detailed review of the request. ITEM 1. We have received all of the data and the initial fee we require to begin a detailed technical review of your request. If additional data are required, we will inform you within days of the date of this letter. However, if application /certification form information is requested in Items 4 or 5 below„ that information must be provided before we can issue our final determination. X 2. We must receive the initial fee balance, $80, before we will begin our review. Payment shall be made in the form of a check or money order made payable in U.S. funds to the National Flood Insurance Program, or by credit card payment. For identification purposes, the case number referenced above must be included on the check or money order. Please forward this payment to: Federal Emergency Management Agency Revisions Fee - Collection System Administrator P.O. Bog 3173 Merrifield, Virginia 22116 3. Based on our initial review of your request, we have determined that the total processing costs will exceed [$3,500/6,500]. Please provide written authorization for us to proceed with our review to a limit of $ 4. All applicable forms from the enclosed Application /Certification Forms" package and the necessary supporting data, as described in the package instructions, must be submitted. X 5. The following forms, which were omitted from your previous submittal, must be provided: a. Form 1, entitled "Revision Requester and Community Official Form" b. Form 2, entitled "Certification by Registered Professional Engineer and /or Land Surveyor" C. Form 3, entitled "Hydrologic Analysis Form" d. Form 4, entitled "Riverine Hydraulic Analysis Form" X e. Form 5, entitled "Riverine Mapping Form" X f. Form 6, entitled "Channelization Form" g. Form 7, entitled "Bridge /Culvert Form" (one form per new /revised bridge /culvert) h. Form 8, entitled "Levee /Floodwall System Analysis Form" i. Form 9, entitled "Coastal Analysis Form" 3 j. Form 10, entitled "Coastal Structures Form" k. Form 11, entitled "Dam Form" 1. Form 12, entitled "Alluvial Fan Flooding Form" X 6. With this letter, we are returning the original package indicating those forms that have not been completed in their entirety or on which data were requested. The item(s) that must be completed and /or statement(s) requesting data have /has been marked with an asterisk M. Please revise and resubmit the form package. 7. Other: Please note that if all of the required items are not submitted within 90 days of the date of this letter, any subsequent request will be treated as an original submittal and will be subject to all submittal /payment procedures, including the initial fees. For a flood - control project to be exempt from fees and processing costs, it must be sponsored by a Federal, State, or local government, intended for public benefit, and primarily intended for flood -loss reduction to insurable structures in identified flood hazard areas that were in existence prior to commencement of construction of the flood - control project. All required data (except the initial fee) and questions concerning your request are to be directed to our Technical Evaluation Contractor at the following address: Michael Baker Jr., Inc. 3601 Eisenhower Avenue Suite 600 Alexandria, Virginia 22304 (703) 960 -8800 Attention: Mr. David P. Preusch, P.E. When you write us about your request, please include the case number referenced above in your letter. 4 If you have any questions concerning FEMA policy, or the NFIP in general, please contact Mr. John Magnotti of our staff in Washington, DC, at (202) 646 -3932, or by facsimile at (202) 646 -3445. Sincerely, La la-,.- Q- William R. Locke Chief, Risk Studies Division Federal Insurance Administration Enclosures cc: Mr. William A. Anderson, P.E. Dowdey, Anderson and Associates, Inc. FEMA USE ONLY o e FORM 1 REVISION REQUESTOR AND COMMUNITY OFFICIAL FORM 1. The basis for this revision request is (are): (check all that apply) ❑ Physical change 0 Existing ® Proposed ❑ Improved methodology ® Improved data ❑ Floodway revision ❑ Other Explain 2. Flooding Source: 3. Project Name/Identifier-. A1H10,U Z098/J TD 5-,'IM/Z/ d 4. FEMA zone designations affected: A F (example: A, AH, AO, Al -.A30, A90& V, VI-V30, VE, B, C, D, X) 5. The NFIP map panel(s) affected for all impacted communities is (are): Community Community Riverine Map Panel Effective No. Name County State No. No. Date _ EX: 480301 Katy, City Harris, Fort Bend TX 480301 0005D 02/08/83 480287 Harris County Harris TX 48201C 0220G 09/28/90 49t9l7e2 C4OGPELL MIM,5- ARID DE,( 170 0010 D 6. The submitted request encompasses the following types of flooding, structures, and associated disciplines: (check all that apply) Structures ❑ Channelization ❑ Levee/Floodwall ❑ Bridge/Culvert ❑ :Dam ❑ Coastal Fill ❑ Pump Station ❑ :none ❑ Other (describe) Disciylines' ,® Tomes of Floodine Riverine ❑ Coastal ❑ Alluvial Fan (Z Shallow Flooding ❑ Lakes ❑ Affected by ❑ wind/wave action ❑ ❑ Yes ® No ❑ Other (describe) Structures ❑ Channelization ❑ Levee/Floodwall ❑ Bridge/Culvert ❑ :Dam ❑ Coastal Fill ❑ Pump Station ❑ :none ❑ Other (describe) Disciylines' ,® Water Resources ® Hydrology [� Hydraulics ® Sediment Transport Interior Drainage ❑ Structural ❑ Geotechnical ❑ Land Surveying ❑ Other (describe) Attach completed "Certification by Registered Professional Form for each discipline checked. (Form 2) October 1992 APPLICATIONICERTITICATION FORKS FOR CONDMONAL LETTER OF YAP U'VIsiON. LITTER OF IMP o '�� :AL YAP REVISION Kt; V l,lUIN K> +1�U t.� TUK Eil`i L LrvMMU 1`111 I yr r a%,Lz%j r vr%— Fioodway 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? MYes [RNo to CX4ti a., of � kN. Q,(L . If yes, give reason: -be aor as+ U" Attach request to revise the floodway from community CEO or designated official. 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. Does the State have jurisdiction over the floodway or it's adoption by communities participating in the NFIP? 0Yes ❑ 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. �/,4 prnnnlud Encroachments With floodways: 1A. Does the revision request involve fill, new construction, substantial improve ent, or other in the floodway? ❑ Yes WNo see- development Vi, , � ,��ocrv�wfia, 1B. If yes, does the development cause the 100 -year water surface elevation increase at any ioo o�- location by more than 0.000 feet? ❑ Yes ❑ No o��`G:Qek- Without floodways: }0 �c 2A. Does the revision request involve fill, new construction, substantial improvement, or other development in the 100 -year floodplain? M Yes No 2B. If yes, does the cumulative effect of all development that has occurred 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 if community or state has adopted more stringent criteria)? ❑ Yes Er No If answer to either Items 111 or 2B is yes, please provide documentation that all requirements of Section 65.12 of the NFIP regulations have been met. Kevision Having read NFIP Re lations, 44 CFR Ch. 1, parts 59, 60, 61, 65, and 72, I believe that the proposed revision Re ❑ is not in compliance with the requirements of the aforementioned NFIP Regulations. n__........;�„ riMw:ol Aeknnwledwement e Was this revision request reviewed by the community for compliance with the mnity's adopted floodplain management ordinances? Yes No • Does this revision request have the endorsement of the community? [�s ❑ 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 65.4 (b) of the NFIP Regulations. n _rr November 1992 raise WA v APPLICATIONICERTIFICATION FORKS FOR CONDMONAL LETTER of HAT REVISION. LETTER of HAP REVISION AND PHYSICAL HAT REVIMON 1w •guava. ♦wgvr..da v —CXIIL Vv..aa•.v•.aa a va a a va•... Operation and Maintenance • Does the physical change involve a. flood control structure (e.g., levees, floodwalls, channelization, basins, dams)? ❑ Yes 0 No if yes, please provide the following information for each of the new flood control structures: A. Inspection of the flood control project will be conducted periodically by (entity) with a maximum interval of months between inspections. B. Based on the results of scheduled periodic inspections, appropriate maintenance of the flood control facilities will be conducted by (entity) to ensure the integrity and degree of flood protection of the structure. C. A formal plan of operation, including documentation of the flood warning system, specific actions and assignments of responsibility by individual name or title, and provisions for testing the plan at intervals not less than one year, ❑ has ❑ has not been prepared for the flood control structure. D. The community is willing to assume responsibility for ❑ performing ❑ overseeing compliance with the maintenance and operation plans of the (Name) flood control structure. If not performed promptly by an owner other than the community, the community will provide the necessary services without cost to the Federal government. Attach operation and maintenance plans 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: � yC. d a th . t if built as •i l C. J CLOMR. A letter from FEMA commenting on w er a propose pro�ec , - -- proposed, would justify a map revision (LOMR or PMR), or proposed hydrology changes (see 44 CFR Ch. 1, Parts 60, 65, and 72). LOMR A letter from FEMA officially revising the current NFIP map to show changes to floodplains, floodways, or flood elevations. LOMRs typically depict decreased flood hazards. (See 44 CFR Ch. 1, Parts 60 and 65.) PMR A reprinted NFIP map incorporating changes to floodplains, 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 hazards or large -scope changes. (See 44 CFR Ch. I, Parts 60 and 65.) d. Other: Describe N October 1992 APPLICAnONICZ=nCATION FORKS FOR CONDMONAL LErm of YAP REvwoN, Lrrrn OF MAP RLV m� PRMCAL IMP UTWON Forms Included Form 2 entitled "Certification By Registered Professional Engineer And/Or Land Surveyor" must be 1 submitted. The following forms should be included with this request if (check the included forms): • Hydrologic analysis for riveriine flooding differs from that ❑ Hydrologic Analysis Form (Form 3) M/A used to develop FIRM • Hydraulic analysis for riverine flooding differs from that Riverine Hydraulic Analysis used to develop FIRM (Form 4) 7 • The request is based sow, on updated topographic ❑ Riverine/Coastal Mapping information (Form 5) • The request involves any type of channel modification ❑ Channelization (Form 6) VA • The request involves new bridge or culvert or revised ❑ Bridge/Culvert Form M/A analysis of an existing bridge or culvert (Form 7) • The request involves a new or revised levee/floodwall system ❑ Levee/Floodwall System l IA Analysis (Form 8) • The request involves analysis of coastal flooding ❑ Coastal Analysis Form KI /A (Form 9) • The request involves coastal structures credited as providing ❑ Coastal Structures Form NIA protection from the 100 -year flood (Form 10) • The request involves an existing, proposed, or modified dam ❑ Dam Form (Form 11) NIA} • This request involves structures credited as providing ❑ Alluvial Fan Flooding Form f protection from the 100 -year flood on an alluvial fan (Form 12) initial !review r ee • The minimum initial review fee for the appropriate request category has been included. Yes ❑ No If yes, the amount submitted is $ S60-12- or • This request is for a protect that is for public benefit and is intended to reduce the flood hazard to existing development in identified flood hazard areas as opposed to planned floodplain development. ❑ Yes ❑ No November 1992 Page 4 of 5 APPUCAT1oN/CEM ICA77ON FORKS FOR CONDMONat LET Ea or jw jc=oeq. LLT = or fur uvLvoN axe FR=Cat. nat at=ON Note: I understand that my signature indicates that all information submitted in support of this request is correct. Note: Signature indicates that the community understands, from the revision requestor, the impacts of the revision on flooding conditions in the community. Signature of Revision Requestor 9719tuie of CotttlOfficial 1541j�,C2so�y 111�r Kevwhe \ M.C��FF►u P.E_ . Clty icy ;H�ttz Printed Name and Title of Revision Requestor Printed Name and Title of.Commumty Official /%/D!/r/wy, / AtioF,�SO�c/ /fSsoc ., �.�� 1&,7 /�.9G1.9s �SZB i 0� C,o nee 11 Company Name Community Name Date / Date \1 - M • 213 Attach letters from all affected jurisdictions acknowledging revision request and approving changes to floodway, if applicable. Note: Although a photograph of physical changes' pot required, it maybe helpful for FEMA's review. /5�zi- October 1992 G• 7\, ? �Ip `% P• APPLICATIONiCERTIFICAMON FORKS FOR CONDMONAL LETTER OF HAP MISION. LETTER OF KA� I� PHTIOCALKAP IZCVISION MW �yv 'A 4t�er o-q rut, t V I 411-tIll A�l will. !'%W dui 4 GA7ZW7fM#m;,,'--`-- FEMA USE ON" CERTIFICATION BY REGISTERED PROFESSIONAL ENGINEER AND/OR LAND SURVEYOR FORM 2 1. This certification is in accordance with 44 CFR Ch. I, Section 65.2. 2. I am licensed with an expertise in k4) 2-f �/' /d /C ��ij�E�iZ) (example: water resources (hydcalagy, hydraull , sediment transport, intenor drainage)• structural, geotechnical, land surveying.] 3. I have years experience in the expertise listed above. 4. I have 1231prepared ❑ reviewed the attached supporting data and analyses related to my expertise. 5. I dhave ❑ have not visited and physically viewed the project. 6. In my opinion, the following analyses and/or design, were performed in accordance with sound engineering pra i s: 7. Based upon the following review, the modifications in place have been constructed in general accordance with plans and specifications. Basis for above statement: (check all that apply) a. ❑ Viewed all phases of actual construction. b. ❑ Compared plans and specifications with as -built survey information. c. ❑ Examined plans and specifications and compared with completed projects. d. [Other 13lO"< -,YY) 1;2V 624'I✓ 8. All information submitted in support of this request is correct to the best of my knowledge. I understand that any false statement may be punishable by fine or imprisonment under Title /1/8 /of/ the United States Code, Section 1001. Name: (p ease print or type) Title: (please print or type) Registration No. Expiration Date: I State Type of License bianiature Date NO *Specify Subdiscipline (Optional) Note: Insert not applicable (N /A) when statement does not apply. October 1992 GRIP„ �1A APPLICATIONICERTIFICATION FORKS FOR CONDITIONAL LETTER OF K" REVISION. LETTER OF KAP W1P RVLSION r� mn FE'MA USE ONLY o e FORM 3 HYDROLOGIC ANALYSIS FORM NIA Community Name: Flooding Source: Project Name/Identifier. Hydrologic Analysis in FIS ❑ Approximate study stream (Zone A) ❑ Detailed study stream (briefly explain methodology) Reason for New Hydrologic Analysis ❑ No existing analysis ❑ Improved data (see data revision on page 3) ❑ Changed physical conditions of watershed (explain) ❑ Alternative methodology (justify why the revised model is better than model used in the effective FIS) ❑ Evaluation of proposed conditions (CLOMRs only) (explain) ❑ Other If a computer program/model was used in revising the hydrologic analysis, please provide a diskette with the input files for the 10 -, 50 -,100- and 500 -year recurrence intervals. Only the 100 -year recurrence interval need be included for SFHAs designated as Zone A. Approval of Analysis ❑ Approval of the hydrologic analysis, including the resulting peak discharge value (s) has been provided by the appropriate local, state, or Federal Agency. (i.e., Attach evidence of approval. ❑ Approval of the hydrologic analysis is not required by any local, state or Federal Agency. October 1992 FED BAK` ` Page 1 of 7 A"UCATION.'CERTIFICAnON FORMS FOR CONDMON,AL LETTER OF WIT VMON. LTt NA�OTrMA"P CAL WIT REVISION �� FX Stream Review of Results Comparison of 100 -year Discharges Location: FIS: Revised: cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs Note: When revised discharges are not significantly different than FIS discharges, FEMA may require a confidence limits analysis on attachment D at a later date to complete the review. As is often the case with revision requests, only a portion of a stream may actually be revised or be affected by a revision. Therefore, transition to the unrevised portion is important to maintain the continuity of the study. NFIP regulations stipulate that such a transition must be assured. What is the transition from the proposed discharges to the effective discharges? Please explain how the transition was made (attach separate sheet if necessary). Attach a completed Review of Results page for each flooding source. Is the new hydrologic analysis being developed solely to revise the flow values presented in the FIS (i.e. no changed hydraulic conditions)? ❑ Yes ❑ No If yes, does the 100 -year water - surface elevation change by 1.0 foot or more? ❑ Yes ❑ No FEMA does not normally revise NFIP maps solely due to insignificant flow changes where changes in 100 -year water - surface elevation are less than 1.0 foot. October 1992 Page 2 of 7 APPLICATIONICE=FICATION FORMS rox CONDMONAL LETTER OF HAP 1EMON. LCrrVR OF M" REVISION AND PHTWCAL M" 8EVM014 0 r. orical noodmg information Is historical data available for the flooding source? ❑ yes ❑ No If yes, provide the following: Location along flooding source: Maximum peak discharge: Second highest peak discharge: Source of information: Record Information cfs cfs Location of nearest gage to project site (along flooding source or similar watershed; specify) Gaging Station: Drainage area at gage: _ mi2 Number of years of data: hats Rovisinn Please use the following table to list all the data and/or parameters affected by this request and identify them as new data (New) or as revising existing data (Revised). (If necessary, attach a separate sheet.) Data Parameter New Revised Data Source ❑ ❑ ❑ ❑ ❑ ❑ ❑ ❑ ❑ ❑ • Data source can be from a Federal, State, or local government agency, or from a private source. Some state and local governments may have less strict data requirements than Federal agencies, in which case the data may not be accepted by FEMA unless it is demonstrated that the data give a better estimate of the flood discharge. • Attach documentation corroborating each data source (i.e., certified statement, report, bibliographical reference to a published document). In the case of a published document or a government report, providing copies of the cover and pertinent pages may be helpful. for New ❑ Statistical Analysis of Gage Records (use Attachment A) ❑ Regional Regression Equations (use Attachment 8) ❑ Precipitation/Runoff Model (use Attachment C) ❑ Other (specify; attach backup computations and supporting data) G• October 1992 V�RG Page 3 of 7 N /D¢ A""CATIONrCER=CATION FORKS FOR CON=WNAL LMn OF HAP RL ON L _ , 11 L` �1Yi�P ON AND PHYSICAL 11AP ItLVISION Attachment A: Statistical Analysis of Gage Reco...s Gaging Station: Gage Location (latitude and longitude): 1. Number of vears of data Systematic Historical 2. Homogeneous data 3. Data adjustments 4. Number of high outliers Low outliers Zero events 5. Generalized skew 6. Station skew 7. Adopted skew 8. Probability distribution used (justify if log- Pearson III was not used) 9. Transfer equations to ungaged sites If yes, specify method FIS: ❑ Yes ❑ No ❑ Yes ❑ No Revised: ❑ Yes ❑ No ❑ Yes ❑ No ❑ Yes ❑ No 10. Expected probability' ❑ Yes ❑ No 11. Comparison of results with other analyses ❑ Yes ❑ No If yes, describe comparison FEMA does not accept expected probability analyses for the purpose of reflecting flood hazard information in a FIS. If any data is not available, indicate by N /A. Attach analysis including plot of flood frequency curve. October 1992 Page 4 of 7 ArrucAnox ccar ncwnox rows rot coic=NAL Lmn or MAT arvmw Lmn or aw a nrmoN AND Fm=cAL um mr-MON Attacnment n: 1. Bibliographical Reference: (Attach a copy of title page, table of contents, and pertinent pages including equations.) 2. Gaged or ungaged stream: 3. Hydrologic region(s): _ Attach backup map. 4. Provide parameters, valuers, and source of data used to define parameters. 5. Urbanized conditions calculations 6. Percent of watershed urbanization 7. Is the watershed controlled? FIS: Revised. ❑ Yes ❑ No ❑ Yes ❑ No ❑ Yes ❑ No ❑ Yes ❑ No 8. Comparison with other analyses ❑ Yes ❑ No ❑ Yes ❑ No If the answer to 5, 7, or 8 is yes, explain methodology in Comments. If data is not available, indicate by N /A. Comments Attach computations and supporting maps. October 1992 Page 5 of 7 A"UCATIONCE nMCATION FORMS FOR CON0ITIONAL LETTER OF MAP REVISION. LErm 0 PHYSICAL MAP REVISION Attachment C: 1. Method or model used: Version: Date: 2. Source of rainfall depth: 3. Source of rainfall distribution: 4. Rainfall duration: 5. Areal adjustment to precipitation W: 6. Hydrograph development method: 7. Loss rate method: Source of soils information: Source of land use information: 8. Channel routing method 9. Reservoir routing: 10. Baseflow considerations: If yes, explain how baseflow was determined: )ff Model FIS: ❑ Yes ❑ No ❑ Yes ❑ No Revised: ❑ Yes ❑ No ❑ Yes ❑ No 11. Snowmelt considerations: ❑ Yes ❑ No ❑ Yes ❑ No 12. Model calibration: ❑ Yes ❑ No ❑ Yes ❑ No If yes, explain how calibration was performed. 13. Future land use conditions: ❑ Yes ❑ No If yes, explain why. Note: FEMA policy is to base flooding on existing conditions. If data is not available, indicate by N /A. Attach precipitation/runoff model, hydrologic model schematic, and supporting maps. October 1992 Page 6 of 7 A"UCAnON==nCATION FORMS rOR CON XTWAL LCrrn OF YAA !Lti*Mofi. Ltrrn OF HAP UTMON AND TRYMCAL U" U-MON Attacnment iu: Stream: Select one location for Confidence: Limits Evaluation (describe location): Discharges for selected location: I Exceedance Probability FIS Revised 10% (10 -yeas) cfs cfs 2% (50 -yeas) cfs cfs 1% (100 -year) cis Cfs 0.2% (500 -year) cfs cis 1% (100 -year) Flood Confidence Intervals 9096 Confidence Interval: 5% limit cfs 95% limit cfs 5096 Confidence Interval: 25% limit cfs 75% limit cfs If the value of the 100 -year frequency flood in the FIS is beyond the 50% confidence interval but within the 90% confidence interval, does the 100 -year water - surface elevation change by 1.0 foot or more? ❑ Yes ❑ No An example of confidence limits analysis can be found in Appendix 9 of Bulletin 17B. Attach Confidence Limits Analysis. _L �nK�• gyp,,, INC• rZD 1993 October 1992 P� �dinC Pap 7of7 A'Lti 'I APPLICATION.'CLRMCATION FORKS FOR cONDrrI0NA1. Lrrm OF K" MMON. Lrr= OF Ka Rr=oN AND PH 11 CAL KAP REVMON FEMA USE ONLY M ° FORM 4 RIVERINE HYDRAULIC ANALYSIS FORM Community Name: Flooding Source: Project Name/Identifier. �AT(l Z; —zxz L�lleg8,t'i DFi.� `!lq�r0,� �s>',y�CT Reach to be Revised ... . Downstream limit Z,!:5;1 9X4 Upstream limit Effective FIS ❑ Not studied ❑ Studied by approximate methods Downstream limit of study Upstream limit of study _ l� ,2rStudied by detailed methods Downstream limit of study Upstream limit of study _ Floodway delineated ❑ Downstream limit of floodway Upstream limit of Foodway Z Z 3 742 Hydraulic Analysis Why is the hydraulic analysis different from that used to develop the FIRM. (Check all that apply) Not studied in FIS (561 e029 -?) ❑� Improved hydrologic data/analysis. Explain: ❑ Improved hydraulic analysis. Explain: ❑ Flood control structure. Explain: Other. Explain: October 1992 M10� REC��V age 1 of 5 NOV 3 0 1993 �Q A APPUCAn0N/C=nCAn0N FORMS FOR CONDMONAL. L rrrM OF M" UTM UT= OF �OlJ1�b Irmo -�YrV 3 Models Submitted Full input and output listings along with files on diskette (if 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 e5ective 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 SFHA s with a Zone A designation. rqui LICJ Duplicate Effective Model Natural Foodway 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 data has been transferred correctly to the requestor's equipment and to assure that the revised data will be integrated into the effective data to provide a continuous FIS model upstream and downstream of the revised reach. Corrected Effective Model Natural Fkwdway The corrected effective model is the model that corrects any errors that occur in the duplicate effective model, adds any additional cross sections to the duplicate effective model, or incorporates more detailed topographic information than that used in the currently effective model. The corrected effective model must not reflect any man -made physical changes since the date of the effective model. An error could be a technical error in the modeling procedures, or any construction in the floodplain that occurred prior to the date of the effective model but was not incorporated into the effective model. ❑ Existing or Pre - Project Conditions Model Natu al FlO ay 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 floodplain since the date of the effective model but prior to the construction of the project for which the revision is being requested. If no modification has occurred since the date of the effective model, then this model would be identical to the corrected effective or duplicate effective model. (Z Revised or Post - Project Conditions Model Natural FoWway The existing or pre- proiect 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 floodplain since the effective model was produced as well as the effects of the project. ❑ Other: Please attach a sheet describing all other models Natural Floodway submitted. 0 M October 1992 Page 2 of 5 APPLICATIONICMMFICAnON FORKS FOR CONDITIONAL LrMXR OF YAP UNWON. LZT= OP YAP REMMON AND PRMCALYAP RIrVMON Model Parameters (from model used to revise 100 -vear water surface elevations) Discharges: upstream Limit Downstream Limit 10 -year 12 F00 / Z go o 50 -year Ire o o Igo o 0 100 -year 7 0/ o Zo / o y 500 -year ?/ zoo /- z o 0 Attach diagram showing changes in 100 -year discharge 2. Explain how the starting water surface elevations were determined 5�rc: >io,v 1S440 10 -year 50 -year 100 -year Floodway 500 -year Give range of friction loss coefficients Starting Water Surface Elevation O So- o 4sz. i� 4S7_ / 7 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. (",v —11;:, ) Location Explain: FIS Revised 4. Describe how the cross section geometry data were determined (e.g., field survey, topographic map, taken from, previous study) and list cross sections that were added. /A/ 7i1,e" f/d�/l DV J�fC /SON ry A?1 //-/ 199z O f1 /� Ji ?C2 11993 -0 . „ INC ' October 1992 re,4A CHEaev fozz 6e--YA 4L t i9�CCct�ocY� OcGIZ /�i�2 NOV 3 0 1993 ' A"L'CAT10N=7 Mc&TION rams roz cODtD2 noNAL ,LET n OF NAT UvMON. U""n OF NAT 1�vI M AN SICAL NAT iRCVL u INI H AI.EXAN0FIIA, VIA`" Model Parameters (Cont'd) 5. Explain how reach lengths for channel and overbanks were determined: Results urom mooei uses to revise Luu -year water surface elevations) 1. Do the results indicate: a. Water surface elevations higher than end points of cross sections?❑ Yes ;D-No b. Supercritical depth? ❑ Yes M No c. Critical depth? ❑ Yes No d. Other unique situations? ❑ Yes No If yes to any of the above, attach an explanation 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? ` 7 / 3. What is the distance: between the cross - sections in 2 above? 75' � 4. What is the maximum distance between cross - sections? 7 5. Floodway determination a. What is the maximum surcharge allowed by the community or State? (? d foot b. What is the maximum surcharge for the revised conditions? O foot c. What is the maximum velocity? Q 3 fps d. What type of erosion protection is provided? October 1992 Explain: Z Page 4 of 5 A"UCATION==MCATION FORM FOR CONDSTIONAL LErMR OF U" REV WON. LETTER OF NAP MWON A" P"SICAL YAA RECISION RIVERINE HYDRAULIC ANALYSIS FORM RpQ„ h *Q fr^.,+1.1% 6. Is the discharge value used to determine the floodway anywhere different from that used to determine the natural 100 -year flood elevations? ❑ Yes M No If yes, explain: Attach a Floodway Data Table showing data for each cross sectio listed in the published floodway data table in the FIS report. 7. Do 100 -year water surface elevations increase at any location? ❑ Yes ❑ No If yes, please attach a list of the locations where the increases occur, state whether or not the increases are located on the requestor's property, and provide an explanation of the reason for the increases. A/y/� HD "- Pc AGlS-, Or Pi70P0 L'i - Please attach a completed comparison table entitled: Water Surface Elevation Check. Revised FIRMIFBFM and Flood Profiles A. The revised water surface elevations tie into those computed by the effective FIS Model (10-, 50- ,100 -, and 500 - year), downstream of the project at cross - section 7,0 within feet and upstream of the project at cross section Z2 37 o within 0.07 feet. B. The revised floodway elevations tae into those computed by the effective FIS model, down- stream of the project at cross section ZD9 ,60 within -— _.__.t2:SZ feet and upstream of the project at cross section 72 3' 70 wig 0.00 feet. CAttach profiles, at the same vertical and horizontal scale as the profiles in the effective FIS ? report, showing stream bed and profiles 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. ,}R., INC. KE MICHAEL CvED Proceed to RiverinelCoastal Mapping Form. R - November 1992 P A �AK�DPK=C�AL:Mn"R�r=ON XA APPL1CAr.ONCEnCjLTION FORMS roe COPMMONAL Lrrrm or HAzzvwoN. Lrrm or HA U 7 -- w rI/ 101 I I v L m L: C 00 = E o o ° � d O ri `L V o � r• a4 Y r � U v L ift on m ti o cc Z e wc V V V�f� A �j � m � `\ C o a OU W U V m � a•• Z Q � i � � C O 4! 6 ar'EMA USE ONLY O O FO/R� /M RIVERINE/COASTAL MAPPING FORM / v 4 Community Name: Flooding Source; Project Name/Identifier: Mapping Changes 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 floodplain boundaries (Zone A) Q Yes ❑ No Q N/A B. Revised 100 - and 500 -year floodplain boundaries Q Yes ❑ No ❑ N/A C. Revised 100 -year floodway boundaries Q Yes ❑ No ❑ N/A D. Location and alignment of all cross sections used in the revised hydraulic model with stationing control indicated Q Yes ❑ No ❑ N/A E. Stream alignments, road and dam alignments ❑ Yes ❑ No ❑ N/A F. Current community boundaries Q Yes [] No Q N/A G. Effective 100 - and 500 -year floodplain and 100 -year floodway boundaries from the FIRM/FBFM reduced or enlarged to the scale of the topographic work map Q Yes ❑ No ❑ N/A H. Tie-ins between the effective and revised 100 - and 500 -year floodplains and 100 -year floDdway boundaries Q Yes Q No ❑ N/A I. The requestor's property boundaries and community easements M Yes Q No ❑ N/A J. The signed certification of a registered professional engineer Q Yes ❑ No ❑ N/A K. Location and description of reference marks Q Yes 0 No N/A L. Vertical datum (example: NGVD 1929, NAVD 1988, etc.) Q Yes ❑ No ❑ N/A M. Coastal zone designations tie into adjacent areas not being revised Q Yes Q No ❑ N/A N. Location and alignment of all coastal transects used to revise the coastal analyses Q Yes Q No Q N/A If any of the items above are marked no or N /A, please explain: 2• What is the source and date of the updated topographic information (example: orthophoto maps, July 1985; field survey, May 1979, beach June profiles, 1987, etc.)? 3. What is the scale and contour interval of the following workmaps? a. Effective FIS scale Contour interval b. Revision Request scale Contour interval Note: Revised topographic information must be of equal or Brea G IN gAK�F1 '1 November 1992 v 3 19 Page 1 of 3 i N�/y /� IRGIN +A APPLICATION: CERTIFICATION FORMS FOR COKDti TONAL I.ETfER OF KAP REyLy y� V 7WOO PHTSICALK"REW91ON 0 7µ KI V E KIN E/COASTAL MAPPING FORM Changes (Continued) 4. Attach an annotated FIRM and FBFM at the scale of the effective FIRM and FBFM showinj the revised 100 -year and 500 -year floodplains and the 100 -year floodway boundaries and how they tie into thou shown on the effective FIRM and FBFM downstream and upstream of the revision, or adjaeeat to the area of revision for coastal studies. Attach additional Pages if needed. 5. Flood Boundaries spd 100 -year water surface elevations: Has the 100 -year floodplain been shifted or increased or the 100 -year water surface elevation increased at any location on property other than the requestoes or community's? ❑ Yes ❑ No If yes, please give the location of shift or increase and an explanation for the increase. a. Have the affected property owners been notified of this shift or increase and the effect it will have on their property? ❑ Yes ❑ No If yes, please attach letters from these property owners stating they have no objections to the revised flood boundaries. b. What is the number of insurable structures that will be impacted by this shift or increase? 6. Have the floodway boundaries shifted or increased at any location compared to those shown on the effective FBFM or FIRM? ❑ Yes ❑ No If yes, explain: 7. ire V -zone has been designated, has it been delineated to extend landward to the heel of the primary frontal dune? ❑ Yes ❑ No If no, explain: Manual or digital map submission: ❑ Manual ❑ Digital Digital map submissions may The 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 Page 2 of 3 ACYI.ICATIIIN.CCRTI rICATION TOWS FW WNDITIIONAI. LLTrU Or YAP SCMGN. LM= Or YAP SLVUWN AND PHYSICAL YAP SCVISION IS .0 . QA41VCdr ,%JtLQ L rsL hJj%rrL1N It r U Un Earth Fill Placement 1. Has fill been placed in the regulatory floodway? ❑ Yes ❑ No If yes, please attach completed Riverine Hydraulic Form. 2. Has fill been placed in floodway fringe (area between the floodway and 100 -year floodplain boundaries)? ❑ Yes ❑ No If yes, then complete A, B, C, and 1) below. A. Are fill slopes for granular materials steeper than one vertical on one - and - one -half horizontal? ❑ Yes ❑ No If 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 ❑ No If no, describe erosion protection provided C. Has all fill placed in revised 100 -year floodplain been compacted to 95 percent of the maximum density obtainable with the Standard Proctor Test Method or acceptable equivalent method? ❑ Yes ❑ No D. Can structures conceivably be constructed on the fill at any time in the future? ❑ Yes ❑ No If 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? ❑ Yes ❑ No If yes, is the fill protected from erosion by a flood control structure such as a revetment or seawall? ❑ Yes ❑ No If yes, attach the coastal structures form. November 1992 Awrucar1oN.c=nF1cwr1oN roaxs roa coNomoNAL i.Lrm or AW MICHAEL BAKER. JR., INC. R.ECLIVED A +04A �uv . —., ��nR1A, VIRGINIA Page 3 of 3 + 1 /� sE WON AM rxr$c, L U" RLVWON M FORM 6 CH;ANNELIZATION FORM Community Name: Flooding source: Project Name/Identifier: Downstream limit: Upstream limit: Extent of Channelization Channel Description 1. Describe the inlet to the channel 2. Briefly describe the shape of the channel (both cross sectional and planimetric configuration) and its lining (channel bottom and sides) 3. Describe the outlet from the channel 4. The channelization includes: ❑ Levees ❑ Drop structures ❑ Supereievated sections ❑ Transitions in cross sectional geometry ❑ Debris basin/detention basin ❑ Energy dissipater ❑ Other 5. Attach the following: a. Certified engineering drawings showing channel alignment and locations of inlet, outlet, and items checked in Item 4 b. Typical cross sections and profiles of channel G October 1992 Arrucnn0"CEMMnnoN FORMS roR CONDMONAL t.crrra or K" 1 of 3 ANDF -111 CALF "si WON 1. _ Hydraulic Considerations What is the l0U -year discharge? 2. Do the cross sections in the hydraulic model match cfs 9. What is the design elevation in the channel based on ?: ❑ Subcritical flow ❑ Critical flow ❑ Supercritical flow ❑ Energy grade line Is 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 Outlet of channel At Drop Structures At Transitions Other location. Explain: Q Yes the typical cross sections in the plans? ❑ Yes ❑ No 3. Are the channel banks higher than the 100 -year ❑ Yes ❑ No flood elevations everywhere? ❑ Yes ❑ No 4. Are the channel banks higher than the 100 -year flood energy grade lanes 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? - feet 7. What is the range of the 100 -year flood velocities? - ft/sec 8. What is the lining type? (both bottom and sides) Explain how the channel lining prevents erosion and maintains channel stability (attach documentation) 9. What is the design elevation in the channel based on ?: ❑ Subcritical flow ❑ Critical flow ❑ Supercritical flow ❑ Energy grade line Is 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 Outlet of channel At Drop Structures At Transitions Other location. Explain: Q Yes Q No ❑ Yes Q No ❑ Yes ❑ No ❑ Yes ❑ No If the 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 Pap 2 of 3 AFFWCAnON'CERMCA77ON FORMS FOR CONDMONAL LErrn OF MAT W#WON, LrrrR OT MAT WVMON AND PKMCAL MAT REVMON v�s.u•. "�ai�[711 V1. • V14Tj aeaiment't'ransport Considerations A- Is there any indication from historical records that sediment transport (including scour and deposition) can affect the 100 -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 100 -year water - surface elevations and/or the capacity of the channel? ❑ Yes ❑ No 2• If the answer to either lA or 1B is yes: A. What is the estimated sediment (bed) 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 ❑ 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? ❑ Yes ❑ No October 1992 t,,P 3 of 3 A"LICATIONiCMrMcATiON rona rob CONDITIONAL LZ,7M or &Q It "VMoN. 'XT'= oV AOlt MMM AND PHYSICAL AW n-MON �/A