Attachment 02.04.03-08E TVA letter dated February 8, 2010 RAI Response
ASSOCIATED ATTACHMENTS/ENCLOSURES:
Attachment 02.04.03-8E: Melton Hill Dam Local Watershed (Subbasins 27) Unit Hydrograph Validation. CDQ000020080068
(41 Pages including Cover Sheet) Attachment 02.04.03-08E TVA letter dated February 8, 2010 RAI Response
ASSOCIATED ATTACHMENTS/ENCLOSURES:
Attachment 02.04.03-8E: Melton Hill Dam Local Watershed (Subbasins 27) Unit Hydrograph Validation..
(41 Pages including Cover Sheet) NPG CALCULATION COVERSHEET/CCRIS UPDATE Page 1
REV 0 EDMS/RIMS NO. EDMS TYPE: EDMS ACCESSION NO (N/A for REV. 0) L58090511003 calculations(nuclear) I 5 8 0 9 1 2 3 0 04 41
Calc Title: Melton Hill Dam Local Watershed (Subbasin 27) Unit Hydrograph Validation
CALC ID TYPE ORG PLANT BRANCH NUMBER CUR REV NEW REV REVISION APPLICABILITY ~Entire calc (@ CURRENT CN NUC GEN CEB CDQ000020080068 1 2 Selecled pages [0
NEW No CCRIS Changes [I ACTION NEW El DELETE El SUPERSEDE El CCRIS UPDATE ONLY C (For calc revision, CCRIS REVISION R0 RENAME C DUPLICATE E] I (Venflier Approval Signatures Not been reviewed and no Required) CCRIS changes required)
UNITS SYSTEMS UNIDS N/A N/A N/A DCN.EDC.N/A APPLICABLE DESIGN DOCUMENT(S) CLASSIFICATION See - Below N/A 'E' QUALITY SAFETY RELATED? UNVERIFIED SPECIAL REQUIREMENTS DESIGN OUTPUT SAR/TS and/or ISFS1 RELATED? (If yes, QR = yes) ASSUMPTION AND/OR LIMITING CONDITIONS? ATTACHMENT? SAR/CoC AFFECTED Yes[] No 0 Yes 0 No 0 Yes[l No R YesEl No[] Yes[C No[@ Yes[l No 0 PREPARER ID PREPARER PHONE NO PREPARING ORG (BRANCH) VERIFICATION METHOD NEW METHOD OF ANALYSIS HSSawyer (615) 252-4362 CEB See Page 7 [E Yes 0 No
PREPARIER SIGNATL)RE DATE KER SIGJ TURE DATE
Heather Smith Sawyer _Bill Hamilton VERIFIER SIGNATURE DATE APPROVAL SIGNATURE DATE
Bill_____ ,K~. 9'ct6~ ______1 STATEMENT OF PROBLEM/ABSTRACT ff\A1111 Validate the existing unit hydrograph for the subbasin of the Melton Hill dam watershed (subbasin 27) using the 1973 and 2003 floods of record.
**EDCN-22404A (SQN), EDCN- 5401 BA(WBN), EDCN-Later (BFN)
This calculation contains electronic attachments and must be stored in EDMS as an Adobe .pdf file to maintain the ability to retrieve the electronic attachments.
MICROFICHE/EFICHE Yes El No 09 FICHE NUMBER(S) El LOAD INTO EDMS AND DESTROY 0 LOAD INTO EDMS AND RETURN CALCULATION TO CALCULATION LIBRARY. ADDRESS: LP4D-C o LOAD INTO EDMS AND RETURN CALCULATION TO: TVA 40532110-20081 Page 1 of 2 NEDP-2-1 [10-20-20081 NPG CALCULATION COVERSHEETICCRIS UPDATE Page la
REV 0 EDSWRWS NO. EDMS TYPE: EDMS ACCESSION NO (NIA for REV. 0) IWA 00 .cacuatons(nuclesr) 1 58 0) 0 5 11 Cl-Title: talculation of Initial Flood Flows from Subbasin 27 (Melton Hill Local) for Use in the SOCH Model Calibration and Subsequent Unit Hydrograph Validation NUM1ER C NEwRm REVISION CALC ID TYPE R PLNT R .... APPLICABILI.TY CURRENT CN NUC Entire calc I Selected pages 0 NEW 6N NUC GEN CEB CDQ000020080068 N/A 0
No CCRIS Changes C] ACTION NEW [ DELETE [1 SUPERSEDE [0 CCRIS UPDATE ONLY 0 (Fio cNc revision, CCRIS REVISION 0 RENAME 0 DUPLICATE 0 (Verifier Approval Signatures Not been reviewed and no I Required) CCRIS changes required) UNrs NIDS WA NWA N/A DCN.ED .N/A APPUCABLE DESIGN DOCUMENT(S) CLASSIFICATION NIA WA "E . SAFETY UNVERIFEDI SPECIAL REQUIREMENTS DESIGN OUTPUT SARTMS and/or ISFSI BEL RE (If yes, .ASSMPTION ANOR LHMENT? SAR/CoC AFFECTED OR=yes) Yes[I No Yesr No Yes U No 0 Yes 0 No 0 YesI NoQ PREPARER ID PREPARER PHONE NO PREPARING ORG (BRANCHi VERIFICATioNMETHOD NEW METHODaOF ANALYSIS THJACKSO (301) 228-8323 Bechtel (CEB) Design Review U Yes 0 No PREPARER SIGMA DATE CHECKER SIGNATUR DATE Thomas H.Jac~o 5__S_09 MatWtiaC. Gamey go VERIFIER SI'GN•ATURE / . , DATE .aPRVLSGTR At/.. DATE
STTMENT OF PROBIL14ASR B I)' ' J •; L'
Generate initial local inflow hydrographs for Subbasin 27 (Melton Hill Local) for the March 1973 and May 2003 floods for use In SOCH model calibration and subsequent unit hydrograph validation.
This calculationcontains electronic attachments and must be stored In EDMS as an Adobe .pdf file to maintain the abilltv to retrieve the electronic attachments. MICROFICHE(EFICHE Yes Q No E FICHE NUMBER(S) O LOAD INTO EDMS AND DESTROY [ LOAD INTO EDMS AND RETURN CALCULATION TO CALCULATION MBRARY. ADDRESS: LP4D-C O LOAD INTO EDMS AND RETURN CALCULATION TO. NPG CALCULATION COVERSHEET/CCRIS UPDATE Page lb
REV 0 EDMS/RIMS NO, EDMS TYPE: EDMS ACCESSION NO (NI/A for REV. 0) L58090511003 calculations(nuclear) L 5 8 0 9 0 7 1 0 0 0 1
Cale Title: Melton Hill Darn Local Watershed (Subbasin 27) Unit Hydrograph Validation
CALC ID TYPE ORG PLANT BRANCH NUMBER CUR REV NEW REV REVISION APPLICABILITY 1 Entire calc R CN NUC GEN CEB CDQ000020080068 0 CURRENT Selected pages El
NEW CN NUC SI No CCRIS Changes El ACTION NEW El DELETE El SUPERSEUE 0 CCRIS UPDATE ONLY El (For calc revision, CCRIS REVISION (0 RENAME 0 DUPLICATE El (Verifier Approval Signatures Not been reviewed and no Required) CCRIS changes required)
UNITS SYSTEMS UNIDS N/A N/A N/A DCNEDC,N/A APPLICABLE DESIGN DOCUMENT(S) CLASSIFICATION See - Below N/A "E" QUALITY SAFETY RELATED? UNVERIFIED SPECIAL REQUIREMENTS DESIGN OUTPUT SA-R/TS anidlor ISFS1 RELAT ED? (If yes, OR = yes) ASSUMPTION AND/OR LIMITING CONDITIONS? ATTACHMENT? SAR/CoC AFFECTED Yes 0 NoEl Yes[] No l Yesm No l Yes 0 No Z YesEl No[) Yes 0 No[E PREPARER ID PREPARER PHONE NO PREPARING ORG (BRANCH) VERIFICATION METHOD NEW METHOD OF ANALYSIS HSSa'yer (615) 252-4362 BWSC (CEB) Design Review E1Yes ED No
RER SIGNATURE DATE CHECKER SIGNATURE DATE
Healr Smh Saawyer Bi VERIFIER SIGN TURE DATE APPRO AL SIGNATURE DATE
Bill 4Hamllon '" ri/-£'/ x• :l/•t
STATEMENT OF PROBLEMIABSTRACT
Validate the existing unit hydrograph for the subbasir of the Melton Hill dam watershed (subbasin 27) using the 1973 and 2003 floods of record.
**EDCN-22404 (SQN), EDCN- 54018(WBN), EDCN-Later (BFN)
This calculation contains electronic attachments and must be stored in EDMS as an Adobe .pdf file to maintain the ability to retrieve the electronic attachments.
MICROFICHE/EFICHE Yes El No 0 FICHE NUMBER(S) El LOAD INTO EDMS AND DESTROY 0 LOAD INTO EDMS AND RETURN CALCULATION TO CALCULATION LIBRARY. ADDRESS: LP4D-C El LOAD INTO EDMS AND RETURN CALCULATION TO: NPG CALCULATION COVERSHEET/CCRIS UPDATE Page 2 CALC ID I TYPE IORG I PLANT I BRANCH I NUMBER I REV i CEB CDQ000020080068 21 CN NUC GEN ALTERNATE CALCULATION IDENTIFICATION
BLDG ROOM ELEV COORD/AZIM FIRM Print Report Yes [ I BWSC
CATEGORIES NA KEY NOUNS (A-add, D-delete)
ACTION KEY NOUN A/D KEY NOUN
(A/D _
CROSS-REFERENCES (A-add, C-change, D-delete) ACTION XREF XREF XREF XREF XREF XREF (A/C/D) CODE TYPE PLANT BRANCH NUMBER REV A P CO GEN CEB FLDHYDRO Version 1.0
CCRIS ONLY UPDATES: Following are required only when making keyword/cross reference CCRIS updates and page 1 of form NEDP-2-1 is not included: Heather Smith Sawyer Bill Hamilton PREPARER SIGNATURE DATE CHECKER SIGNATURE DATE
PREPARER PHONE NO. EDMS ACCESSION NO.
TVA 40532[10-20081 Page 2 of 2 NEDP-2-1 [10-20-20081 Page 3 NPG CALCULATION RECORD OF REVISION CALCULATION IDENTIFIER CDQ000020080068 Title Melton Hill Dam Local Watershed (Subbasin 27) Unit Hydrograph, Revision 2
Revision DESCRIPTION OF REVISION No. 0 Initial issue 30 pages This calculation was revised to validate the existing unit hydrograph for the subbasin of the Melton Hill Dam Local Watershed (Subbasin 27) using the 1973 and 2003 floods of record. As a result of this revision, the calculation title has been changed to reflect final validation of the local unit hydrograph. Significant changes to text are marked with a right-hand margin revision bar.
Changes and Additions:
Content on pages I - 11 on RO was modified as indicated on pages 1 - 12 of R1 (additional page added due to page content roll-over to following page) Content on pages 12 - 29 on RO was modified due only to content carry-over and is now equivalent to pages 12 - 30 of RI
Content on page 30 of RO (the final page of RO) was replaced and new pages 31 - 36 were added.
Calculation header was revised (Melton Hill Dam Local Watershed (Subbasin 27) Unit Hydrograph, Revision 1) on all pages revised. Added new electronic Attachments 4-1, 4-2 and 4-3.
Total hardcopy pages Revision 1: 38 This calculation was revised to address the following: 2 " PER 203951-The verification of the original calculation was completed by personnel who had not completed the required NEDP-7 Job Performance Record (JPR). A verification JPR is now in place for all personnel engaged in verification tasks. Checking included only changes made in this revision as the checking of the calculation was not impacted by PER 203951. The verification is inclusive of work completed prior to this revision.
* PER 203872- replace NEDP-2 forms on Pages 2 through 6 with the forms from the NEDP-2 Revision in effect at the time of calculations issuance.
Significant changes in Revision 2 are noted with a right margin revision bar. Administrative changes and typos are excluded.
The unverified assumption associated with the approval of the Nickajack SOCH.Calibration calculation, CDQ000020080040, has been removed. Final calibration has been completed and the calculation has been approved.
Changes and additions: Content on pages 1-7, 9-10, and 31 - 35 RI has been modified as indicated on pages 1-7, 9-10, and 31-35, R2.
Pages lb and 7b were added.
I Total hardcopy pages Revision 2: 40
TVA 40709 [10-2008] Page 1of 1 NEDP-2-2 [10-20-2008] Page 4
NPG CALCULATION TABLE OF CONTENTS Calculation Identifier: CDQ000020080068 Revision: 2
TABLE OF CONTENTS SECTION TITLE PAGE Coversheet and CCRIS Update Sheet 1 Record of Revision 3 Table of Contents 4 Computer Input File Storage/Information Sheet 6 Calculation Verification Form 7 1 P u r p o se ...... 8 2 Refere nces ...... 9 3 A ss um ptions ...... 10 3.1 G ene ral A ssum ptions ...... 10 3.2 U nve rifled A ssum ptions ...... 10 4 Backgr ound ...... 10 5 M ethodol ogy ...... 10 6 D esign Input D ata ...... 13 6.1 Subbasin and Reservoir A reas ...... 13 6.2 U nit H ydrograph O rdinates ...... 15 6.3 Obse rved Stream Flow ...... 16 6.4 Observed D am O utflow s and H eadw ater Elevations ...... 17 6.5 Stage- V olum e Relationship ...... 17 6.6 Obse rved Rainfall ...... 17 7 Corn putations and Analysis ...... 18 7.1 Calculation of D irect Runoff V olum e ...... 18 7.2 Calculation of Effective Precipitation Series ...... 23 7.3 Calculation of A dditional Runoff on M elton H ill Reservoir ...... 26 7.4 H EC- HM S Sim ulations of Flood Events ...... 27 7.5 SO CH M odel Input ...... 31 7.6 SO CH M odel O utput and U nit H ydrograph V alidation ...... 31 8 Concl usions ...... 36 8.1 Unit H ydrograph V alidation ...... 36
Attachment 1-1 N/A Attachment 1-2 N/A Attachment 1-3 N/A Attachment 1-4 N/A Attachment 1-5 N/A Attachment 1-6 N/A Attachment 2-1 N/A Attachment 2-2 N/A Attachment 2-3 N/A Attachment 2-4 N/A Attachment 2-5 N/A Attachment 2-6 N/A Attachment 2-7 N/A Attachment 2-8 N/A Attachment 3-1 N/A Attachment 4-1 N/A Attachment 4-2 N/A Attachment 4-3 N/A Note: N/A indicates document electronically attached.
TVA 40710 [10-2008] Page I of 1 NEDP-2-3 [10-20-2008] Page 5
NPG CALCULATION TABLE OF CONTENTS
Calculation Identifier: CDQ000020080068 Revision: 2
TABLE OF CONTENTS
SECTION TITLE PAGE
List of Tables:
Table 1: Stage-area Relations for M elton Hill Reservoir ...... 14 Table 2: Six-hour Unit Hydrograph Ordinates for the Melton Hill Local Subbasin ...... 16 Table 3: Daily Mass Balance for Subbasin 27 for the March 1973 Flood ...... 19 Table 4: Calculation of Direct Local Runoff Volume for Subbasin 27 for March 1973 Flood ...... 20 Table 5: Daily Mass Balance for Subbasin 27 for the May 2003 Flood ...... 21 Table 6: Calculation of Direct Local Runoff Volume for Subbasin 27 for May 2003 Flood ...... 22 Table 7: Validated 6-hour Unit Hydrograph Ordinates for Subbasin 27 ...... 36
List of Figures:
Figure 1: Location of Melton Hill Dam Subbasin (No. 27) within the Tennessee River Watershed ...... 8 Figure 2: Melton Hill Local Inflow Subbasin (shown in yellow) ...... 13 Figure 3: Six-hour Unit Hydrograph for Subbasin 27 (Melton Hill Dam) ...... 15 Figure 4: Daily Flow Series for Subbasin 27 for the March 1973 Flood ...... 19 Figure 5: Base Flow Separation for M arch 1973 Flood ...... 20 Figure 6: Daily Flow Series for Subbasin 27 for the May 2003 Flood ...... 21 Figure 7: Base Flow Separation for the M ay 2003 Flood ...... 22 Figure 8: API Regions for Application of TVA FLDHYDRO Program ...... 24 Figure 9: Cumulative Precipitation and Runoff Series for March 1973 Event in Subbasin 27 ...... 25 Figure 10: Cumulative Precipitation and Runoff Series for May 2003 Event in Subbasin 27 ...... 26 Figure 11: HEC-HMS Schematic Watershed Model for the Melton Hill 1973 and Melton Hill 2003 S im u latio n s ...... 2 7 Figure 12: HEC-HMS Output for Total Inflow Node for Simulation of March 1973 Flood ...... 29 Figure 13: HEC-HMS Output for Total Inflow Node for Simulation of May 2003 Flood ...... 29 Figure 14: Development of Subbasin 27 Total Local Inflow Hydrograph for March 1973 Flood ...... 30 Figure 15: Development of Subbasin 27 Total Local Inflow Hydrograph for May 2003 Flood ...... 30 Figure 16: Observed and Simulated Stage Hydrographs for the Tennessee River between Norris and M elton H ill D am s, M arch 1973 ...... 32 Figure 17:, Observed and Simulated Discharge Hydrographs at Melton Hill Dam, March 1973 ...... 33 Figure 18: Observed and Simulated Stage Hydrographs between Norris and Melton Hill Dams, M ay 2 0 0 3 ...... 3 4 Figure 19: Observed and Simulated Discharge Hydrographs at Melton Hill Dam, May 2003 ...... 35
TVA 40710 [10-2008] Page I of I NEDP-2-3 [10-20-2008] Page 6
NPG COMPUTER INPUT FILE STORAGE INFORMATION SHEET
Document CDQ000020080068 IRev. 2 1Plant: GEN Subject: Melton Hill Dam Local Watershed (Subbasin 27) Unit Hydrograph Validation Revision 2
[] Electronic storage of the input files for this calculation is not required. Comments:
Z Input files for this calculation have been stored electronically and sufficient identifying information is provided below for each input file. (Any retrieved file requires re-verification of its contents before use.) Electronic Attachment File Name File Location Attachment 1-1 Norris rev0.xls Attached to PDF Attachment 1-2 Meltonhill revO.xls Attached to PDF Attachment 1-3 GriddedPrecipitationDataAllSubbas Attached to PDF ins2003.xls Attachment 1-4 Basin 27 Effective PPT.xls Attached to PDF Attachment 1-5 Basin 27 Runoff Volume Calc.xls Attached to PDF Attachment 1-6 Total Local Hydrograph Attached to PDF Development.xls Attached to PDF Attachment 2-1 UGBasin27.dat Attached to PDF Attachment 2-2 UGBasin27.prn Attached to PDF Attachment 2-3 Basin 27-1973.dat Attached to PDF Attachment 2-4 Basin 27-1973.out Attached to PDF Attachment 2-5 MHReservoir1973.dat Attached to PDF Attachment 2-6 MHReservoirl973.out Attached to PDF Attachment 2-7 Basin27-2003.dat Attached to PDF Attachment 2-8 Basin27-2003.out Attached to PDF
Attachment 3-1 Subbasin27.zip (HEC-HMS project Filekeeper No 312000 file)
Attachment 4-1 Att 4-1 Observed vs. SOCH Mar Attached to PDF 1973 Hydrographs.xls Attachment 4-2 Att_4-2_Observed vs. SOCH May Attached to PDF 2003 Hydrographs.xls Attachment 4-3 Att 4- Attached to PDF 3 Melton Hill Validated_6HRUH. Axs -I Microfiche/eFiche
TVA 40535 [10-2008] Page 1 of I NEDP-2-6 [10-20-2008] Page 7 NPG CALCULATION VERIFICATION FORM
Calculation Identifier CDQ000020080068 Revision 2 Method of verification used: 1. Design Review 2. Alternate Calculation 0D Verifier 'W 4..6-•,,.•lýate iLIo/)/
3. Qualification Test ED Bill Hamilton Comments:
This calculation entitled, "Melton Hill Dam Local Watershed (Subbasin 27) Unit Hydrograph Validation" was verified by independent design review. The process involved a critical review of the calculation to ensure that it is correct and complete, uses. appropriate methodologies, and achieves its intended purpose. The inputs were reviewed and determined to be appropriate inputs for this calculation. The results of the calculation were reviewed and were found to be reasonable and consistent with the inputs provided. Backup files and documents were consulted as necessary to verify data and analysis details found in the calculation.
Detailed comments and editorial suggestions for the changes made in this revision were transmitted to the author and reviewer by email along with a marked up copy of the calculation.
(Note: The design verification of this calculation revision is for the total calculation, not just the changes made in the revision. This complete re-verification is performed to disposition PER 203951 as described in the Calculation Revision Log on Page 3).
TVA 40533 [10-2008] Pag el1oflI N .EDP-2-4 [10-20-20081 Page 7a
NPG CALCULATION VERIFICATION FORM
Calculation Identifier CDQ000020080068 Revision 0 Method of verification used: 1. Design Review 2. Alternate Calculation El Verifier Bob Swain Date 4/29/2009 3. Qualification Test D--_ Comments:
The calculation entitled, "Calculation of Initial Flood Flows from Subbasin 27 (Melton Hill Local) for Use in the SOCH Model Calibration and Subsequent Unit Hydrograph Validation" was verified by an independent design review. The process involved a critical review of the calculation to ensure that it is correct and complete, uses appropriate methodologies, and achieves its intended purpose. Backup files and documents were consulted as necessary to verify data and analysis details found in the calculation. Detailed comments and editorial suggestions were transmitted to the author and reviewer by email along with a marked up copy of the calculation. Several issues were discussed and resolved during the verification process. Almost all of the editorial suggestions were adopted in the final document.
The calculation presents the development of initial simulated flows from Subbasin 27 for floods that occurred in March 1973 and May 2003. The initial simulated flows are for use in the calibration of the SOCH model for Subbasin 27. Subsequent calculations with the SOCH model will be used for Subbasin 27 local inflow unit hydrograph validation. Page 7b
NPG CALCULATION VERIFICATION FORM
Calculation Identifier CDQ000020080068 Revision 1
Method of verification used: 1. Design Review 2. Alternate Calculation Il Verifier Bill Hamilton Date 7/2/2009 3. Qualification Test __ Comments:
The calculation entitled, "Melton Hill Local Watershed (Subbasin 27) Unit Hydrograph Validation" was verified by an independent design review. The process involved a critical review of the calculation to ensure that it is correct and complete, uses appropriate methodologies, and achieves its intended purpose. Backup files and documents were consulted as necessary to verify data and analysis details found in the calculation. Detailed comments and editorial suggestions were transmitted to the author and reviewer by email along with a marked up copy of the calculation.
The calculation presents the development of initial simulated flows from Subbasin 27 for floods that occurred in March 1973 and May 2003, which were used in the calibration of the SOCH model and to validate the unit hydrograph for Subbasin 27. The comparison between the observed and simulated flows and water surface elevation at several locations supports the conclusion that the unit hydrograph developed for Subbasin 27 has been indirectly validated against floods that occurred in March 1973 and May 2003. TVA Calculation No. CDQ000020080068 Rev: 1 Plant: GEN Page: 8 Melton Hill Local Watershed (Subbasin 27) Unit Hydrograph Validation Prepared HLSS Checked BH
1 Purpose
The Tennessee Valley Authority's (TVA) Water Management Group has adapted computer codes and data sets developed from flood studies carried out over the past 40 years (Reference 8) to develop a dynamic hydrologic model of the Tennessee River upstream of the Guntersville Dam for use in the Probable Maximum Flood (PMF) and dam break analysis for the Sequoyah, Watts Bar, and planned Bellefonte Nuclear Plant sites (note that this calculation will also be used in a similar future PMF and dam break analysis for the Browns Ferry Nuclear Power Plant).
Inputs to the dynamic model include hydrographs for 47 subbasins developed from design rainfall inputs convoluted with unit hydrographs (UH) developed specifically for each subbasin. The unit hydrographs were developed by the TVA in previous studies, mostly in the 1960s, 1970s, and early 1980s, utilizing observed rainfall and stream flow and reservoir headwater and discharge data, and are being validated by checking their performance in reproducing recent floods.
This calculation presents the preparation of initial simulated local inflow hydrograph from Subbasin 27, which is located on the Clinch River, 23.1 miles upstream of its confluence with the Tennessee River, as well as the validation of the unit hydrograph for the subbasin, for floods that occurred in March 1973 and May 2003. Local inflows will be simulated for the floods that occurred in March 1973 and May 2003 to be used for the calibration of the TVA's Simulated Open Channel Hydraulic (SOCH) computer model and to validate the unit hydrograph for Subbasin 27. Subbasin 27 is located in the Tennessee River watershed as shown in Figure 1.
Figure 1: Location of Melton Hill Dam Subbasin (No. 27) within the Tennessee River Watershed TVA Calculation No. CDQ000020080068 Rev: 2 Plant: GEN Page: 9 Melton Hill Local Watershed (Subbasin 27) Unit Hydrograph Validation Prepared HLSS Checked BH
2 References
1. Chow, V.T., D.R. Maidment, and L.W. Mays, Applied Hydrology, McGraw-Hill Book Company, 1988. 2. Linsley, R.K., Kohler, M.A., and J.L. Paulhus, Hydrologyfor Engineers, McGraw-Hill Book Company 1982. 3. Kohler, M.A., and R.K. Linsley, Predicting the Runoff from Storm Rainfall, Research PaperNo. 34, U.S. Department of Commerce, September 1951. (EDMS No. L5 8 080910 001) 4. Newton, D.R., and J.W. Vinyard, Computer-Determined Unit Hydrograph from Floods, Journalof the Hydraulics Division, ASCE, Vol. 93, No. HY5, September, 1967. 5. Tennessee Valley Authority, UNITGRPH-FLDHYDRO-TRBROUTE-CHANROUT User Documentation, Version 1.0, March 2009 (EDMS L58 090325 001) 6. Tennessee Valley Authority, Unit Area 27, Melton Hill Dam, File Book Reference. (EDMS No. L58 090123 801) 7. Tennessee Valley Authority, Calculation No. CDQ000020080055, Processingand Validation of National Weather Service's NEXRAD Stage III Hourly PrecipitationData for Hydrologic Analysis of TVA Subbasins, Revision 3 8. Tennessee Valley Authority, Bellefonte Nuclear Plant - White Paper,Hydrologic Analysis, Revision 1, July 25, 2008. (EDMS No. L58 080725 006) FOR INFORMATION ONLY 9. Tennessee Valley Authority, Office of Environment & Research, Geographic Information & Engineering, Drainage Areas above Guntersville, June 18, 2008 Drawing #6GIE 301 E 200801 ROD 10. Tennessee Valley Authority, Rainfall data for the March 1973 storm - subbasin 27, Response to Bechtel Request for Information RFI 25447-000-GRI-GEX-00039, Rev. 0, 9/25/2008. (EDMS No. L58 081030 004) 11. Tennessee Valley Authority, Rainfall data for the March 1973 storm - subbasin 27, Response to Bechtel Request for Information RFl 25447-000-GRI-GEX-00039, Rev. 1, 12/17/2008. (EDMS No. L58 081217 800) 12. U.S. Army Corps of Engineers, Hydrologic Modeling System HEC-HMS User's Manual, Version 3.2, April 2008. 13. U.S. Army Corps of Engineers, Hydrologic Modeling System HEC-HMS Technical Reference Manual, March 2000. 14. Viessman, W., J.W. Knapp, G.L. Lewis, and T.E. Harbaugh, Introduction to Hydrology, Second Edition, Harper & Row, Publishers, 1977. 15. Tennessee Valley Authority, Data request for developing inflows to the SOCH model for the 1973 flood, for stage-storage tables, and for all reservoir and stream flow data for years 1997 to 2007, Response to Bechtel Request for Information RFI 25447-000-GRI-GEX-00053, Rev. 0, 11/12/2008. (EDMS No. L58 081126 800) 16. Tennessee Valley Authority, TVA Water Control Projects and Other Major Hydro Developments in the Tennessee and Cumberland Valleys, Technical Monograph No. 55, Volume 1, Knoxville, TN, March 1980. 17. Tennessee Valley Authority, Calculation CDQ00020080038, SOCH Model Calibration, Melton Hill, Rev 0, (not approved). 18. American Nuclear Society, American National Standardfor DeterminingDesign Basis Flooding at Power Reactor Sites, ANSI/ANS-2.8-1992, 1992. 19. US Nuclear Regulatory Commission, Standard Review Plan 2.4.3, ProbableMaximum Flood (PMF) on Streams and Rivers, NUREG-0800, Revision 4, March 2007. TVA Calculation No. CDQ000020080068 Rev: 2 Plant: GEN Page: 10 Melton Hill Local Watershed (Subbasin 27) Unit Hydrograph Validation Prepared HLSS Checked RH
3 Assumptions 3.1 GeneralAssumptions None
3.2 Unverified Assumptions None 4 Background
The unit hydrograph is used to predict the runoff response at the outlet of a watershed, or subbasin, to the input of one inch of excess rainfall applied over a given duration of time. Runoff from other depths of excess rainfall can be obtained by scaling (References 1, 2, and 14).
The direct runoff hydrograph (i.e. stream flow minus base flow) can be calculated from a series of M excess rainfall inputs of any depth and the K ordinates of the unit hydrograph using the process of "convolution." The N = K + M -1 ordinates of the direct runoff hydrograph are given by the discrete convolution equation, which states that the direct runoff Qn at a given time n is obtained from the excess runoff Pm and the unit hydrograph ordinate U,-,+ 1 (where Ui = 0 for all i = n - m + 1 > K) as follows (Reference 1):
n The reverse process, called deconvolution, can be used to derive the ordinates of the unit hydrograph (U), from excess rainfall (P) and direct runoff (Q) derived from observed data. Unit hydrograph theory is applicable under the following conditions (References 1 and 2): 1. Excess rainfall has a constant intensity within the effective duration. 2. Excess rainfall is uniformly distributed over the entire subbasin. 3. The duration of direct runoff resulting from a unit of excess rainfall is constant. 4. The ordinates of the unit hydrograph are directly proportional to the total amount of direct runoff (linear response). 5. The surface runoff hydrograph reflects all the unique physical characteristics and runoff processes in the drainage basin in a given "epoch." TVA Calculation No. CDQ000020080068 Rev: 1 Plant: GEN Page: 11 Melton Hill Local Watershed (Subbasin 27) Unit Hydrograph Validation Prepared HLSS Checked BH 5 Methodology Direct runoff originating within several subbasins of the Tennessee Valley watershed, which empty directly into the Tennessee River, cannot be accurately calculated because the observed flood hydrograph at the subbasin outlet is not available. For these subbasins, the TVA will employ SOCH model results to validate the unit hydrograph. The SOCH model requires estimated local inflow flood hydrographs for these subbasins as inputs during the model calibration process, and outputs the stage and discharge hydrographs at selected locations for each run. The local inflow hydrographs are developed using the TVA unit hydrographs and effective rainfall inputs, estimated with the TVA's FLDHYDRO program. The runoff volumes used in adjusting the effective rainfall depths in FLDHYDRO are based on daily water budgets for the appropriate reach of the river. This calculation provides the first iteration local hydrographs for input to the SOCH model which will be used for calibration. The inputs for the simulation of the March 1973 and May 2003 events include runoff from rainfall directly over the reservoir area, and estimated initial local inflow flood hydrographs for the subbasin. The methodology used for unit hydrograph validation follows that described in ANSI/ANS-2.8-1992 (Reference 18). This document is included as a reference in the NRC's Standard Review Plan 2.4.3, ProbableMaximum Flood on Streams and Rivers (Reference 19). ANSI/ANS-2.8-1992 states that "deterministic simulation models including unit hydrographs should be verified or calibrated by comparing results of the simulation with the highest two or more floods for which suitable precipitation data are available." The following methodology was used for the preparation of this data. 1. Develop and perform daily water budget calculations for the March 1973 and May 2003 floods to estimate the daily local runoff volumes for Subbasin 27. 2. Separate base flow from the total local flow to obtain the direct runoff volume from the subbasin and convert to a depth, in inches, for use as the CHKVOL parameter in FLDHYDRO (Reference 5). 3. Obtain observed rainfall data for the March 1973 and May 2003 floods and calculate the basin- average rainfall for each subbasin and also for the reservoir area. 4. Convert the observed rainfall series to an excess precipitation series using the TVA's Antecedent Precipitation Index (API)/Runoff Index (RI) method as implemented in FLDHYDRO. Develop the abstracted rainfall series by subtracting the effective precipitation from the total precipitation series. TVA Calculation No. CDQ000020080068 Rev: 1 Plant: GEN Page: 12 Melton Hill Local Watershed (Subbasin 27) Unit Hydrograph Validation Prepared HLSS Checked BH 5. Use the effective rainfall series and the TVA unit hydrograph as inputs for Subbasin 27 and the abstracted rainfall series for the reservoir in a HEC-HMS (References 12 and 13) model of the watershed to obtain the total direct runoff hydrograph for the two validation storms. 6. Develop a base flow series by linear interpolation of daily basin average values and add it to the total direct runoff to get the total local inflow hydrograph for the two validation floods. 7. Compare the SOCH model simulated and the observed discharge and stage hydrographs for appropriate stations along the Clinch River to indirectly validate the performance of the TVA unit hydrographs in simulating local runoff along the study reach of the Clinch River. Detailed discussions of these procedures are provided in following sections of this calculation. TVA Calculation No. CDQ000020080068 Rev: 0 Plant: GEN Page: 13 Melton Hill Local Watershed (Subbasin 27) Unit Hydrograph Validation Prepared T.H.J Checked M.C.C 6 Design Input Data The input data necessary to simulate the initial flood hydrograph for the Melton Hill Dam, Subbasin 27, are summarized below. * Subbasin drainage area and surface area of Melton Hill Reservoir * Unit hydrograph ordinates and duration * Observed outflows from Norris and Melton Hill Dams and corresponding headwater elevations " The stage-volume relationship for Melton Hill Reservoir * Observed rainfall data associated with the March 1973 and May 2003 floods Each of these inputs is described in more detail in the following subsections. 6.1 Subbasin and Reservoir Areas The drainage area of the Melton Hill Dam subbasin, shown in Figure 2, is given in the TVA File Book Reference as 431 mi2 (Reference 6) and was calculated in GIS as 431.9 mi2 (Reference 9). The GIS area is used in this calculation. Figure 2: Melton Hill Local Inflow Subbasin (shown in yellow) TVA Calculation No. CDQ000020080068 Melton Hill Local Watershed (Subbasin 27) Unit Hydrograph Validation The Melton Hill Reservoir is located entirely within Subbasin 27. In previous calculations, the TVA has utilized a surface area for the reservoir of 8.74 mi2 (Reference 10). Based on the linear interpolation of stage-area relationships developed for the reservoir in 1963 (Reference 16) using the Goal Seek function in EXCEL, that area coincides with an elevation of 794.57 ft MSL, as shown in Table 1. This value is consistent with the daily average water surface elevations provided by the TVA for the Melton Hill reservoir during the periods of study. Table 1: Stage-area Relations for Melton Hill Reservoir 1963 1963 Elev. Area Area dA/dE (feet) (acres)* (sq. mi.) * 730 30 0.05 0.0531 740 370 0.58 0.0563 750 730 1.14 0.0641 760 1,140 1.78 0.1250 770 1,940 3.03 0.1906 780 3,160 4.94 0.2203 790 4,570 7.14 0.3500 795 5,690 8.89 0.3125 796 5,890 9.20 0.3359 800 6,750 10.55 •7wr:'_"7•1 I 8.74 * Stage-area data from Reference 17 ** Interpolation from table using Area(y) = Ao + dA/dE*AA TVA Calculation No. CDQ000020080068 Rev: 0 Plant: GEN Page: 15 Melton Hill Local Watershed (Subbasin 27) Unit Hydrograph Validation Prepared T.H.J Checked M.C.C 6.2 Unit Hydrograph Ordinates The unit hydrograph for this subbasin is described in the TVA File Book Reference (Reference 6) and was developed using the methodology proposed by Newton and Vinyard (Reference 4). Stream flow and precipitation records for the following historical floods were used in the unit hydrograph development: * March 6-10, 1967 * December 30, 1969 - January 3, 1970 * March 15-20, 1973 The flood hydrographs used to develop the local runoff unit hydrograph for Subbasin 27 were determined from lag-routing and hydrograph separation according to the following relationship: IMH = OMH + ASMH - ON where IMH is the local inflow to Melton Hill Reservoir, OMH is the observed outflow from Melton Hill Dam, ASMH is the change in storage within Melton Hill Reservoir, and ON is the outflow from Norris Dam, lagged by six hours. A unit hydrograph was obtained from the rainfall and runoff for each of the three floods using the process of deconvolution, and a composite unit hydrograph was developed in UNITGRPH (Reference 5). The unit hydrograph was regenerated using the revised UNITGRPH program; input and output files are provided as Attachments 2-1 and 2-2, respectively. The resulting composite six-hour unit hydrograph is plotted in Figure 3. The time base and ordinates for the derived unit hydrograph are provided in Table 2 along with a volume check demonstrating that volume of runoff is equivalent to one inch of excess rainfall over the entire basin. 14,000 12,000 • . 10,000 8,000 6000 •~ 6,00.... - __ - 4,000 _" . 2,000 .. __ 0 6 12 18 24 30 36 42 48 54 60 66 72 78 84 90 Time, hours Figure 3: Six-hour Unit Hydrograph for Subbasin 27 (Melton Hill Dam) TVA Calculation No. CDQ000020080068 Melton Hill Local Watershed (Subbasin 27) Unit Hydrograph Validation Table 2: Six-hour Unit Hydrograph Ordinates for the Melton Hill Local Subbasin Hour Q, cfs Q ave, cfs (1) Volume, acft (2) 0 0 6,265 3,107 6 12,530 11,348 5,627 12 10,165 9,008 4,467 18 7,850 6,624 3,284 24 5,397 4,171 2,068 30 2,945 2,655 1,316 36 2,364 2,073 1,028 42 1,782 1,492 740 48 1,201 910 451 54 619 569 282 60 519 469 232 66 418 368 182 72 318 268 133 78 218 168 83 84 117 59 29 90 0 0 0 Total Volume 23,030 acft 2 Basin area 431.9 mi 1.000 inches Notes: 1) Qwe = 0.5(Q, + Q,1 ) * lacft 2) Volume = Qave 3 * 3600 ' * 6hr 3 eCC hr 43560fi 3) Volume.acft mi 2 12.inch Area.mi2 640.acre f! 6.3 Observed Stream Flow No observed stream flow data are used for this calculation. TVA Calculation No. CDQ000020080068 Rev: 0 Plant: GEN Page: 17 Melton Hill Local Watershed (Subbasin 27) Unit Hydrograph Validation Prepared T.H.J Checked M.C.C 6.4 Observed Dam Outflows and Headwater Elevations The daily total discharge from Norris Dam is used as the upstream input for the local inflow water budget. Daily discharge values were obtained from the TVA in the spreadsheet "norrisrev0.xls," provided with this calculation as Attachment 1-1 (Reference 15). Inflows to Melton Hill Reservoir from Subbasin 27 are obtained by a solution of the daily water budget for the reservoir, as presented in Section 7.1. The daily starting stages and daily total outflows (including spills and turbine discharges) from Melton Hill Dam used for the calculation were obtained from the TVA in the spreadsheet "meltonhillrev0.xls," which is provided as Attachment 1-2 to this calculation (Reference 15). 6.5 Stage-Volume Relationship It was not necessary to use the stage-volume relationship for the Melton Hill Reservoir in this calculation. The storage volume measured for the starting stage for each day was provided by the TVA directly in the spreadsheet "meltonhillrev0.xls," as discussed above. 6.6 Observed Rainfall Basin average hourly rainfall depths for the 1973 flood were obtained from the TVA in FLDHYDRO input files (References 10, 11) for the total watershed and for the area of the reservoir. Basin average hourly rainfall depths for the 2003 flood were developed from National Weather Service (NWS) gridded precipitation data sets. NWS NEXRAD Stage III hourly precipitation data were obtained from the Lower Mississippi River Forecast Center (LMRFC) from January 1997 to April 2008 for unit hydrograph validation. A Microsoft.Net utility was developed to generate radar-based Mean Areal Precipitation (MAPX) time series for each of the subbasins (Reference 7). The utility reads the raw hourly precipitation depth data for each 4-km square grid cell, performs necessary coordinate system and projection calculations, and then calculates the average precipitation depth within each subbasin, grouping output into a matrix of MAPX elements arrayed by subbasin and time (Greenwich Mean Time, GMT). Each column of this matrix is equivalent to an annual hyetograph for each subbasin in the TVA model. The hourly precipitation series developed from NWS gridded data for use in the calculation are provided in the spreadsheets "GriddedPrecipitationDataAllSubbasins2003.xls" (Attachment 1-3). The conversion of the time base of the precipitation time series to Central Time for the May 2003 event, and unit conversion and reformatting required for input to FLDHYDRO (see Section 7.2) are carried out in the spreadsheet "Basin 27 Effective PPT.xls," provided as Attachment 1-4. TVA Calculation No. CDQ000020080068 Rev: 0 Plant: GEN Page: 18 Melton Hill Local Watershed (Subbasin 27) Unit Hydrograph Validation Prepared T.H.J Checked M.C.C 7 Computations and Analysis Computations required for the development of the initial local inflow hydrographs for input to the SOCH model and for validation of the TVA unit hydrographs are presented in the following sections. 7.1 Calculationof Direct Runoff Volume A daily water budget is used to estimate the total volume of direct runoff arising locally within Subbasin 27. The volume of local inflow is determined from a mass balance developed for the study reach (i.e. the Clinch River between the Norris and Melton Hill Dams). The mass balance for the reach can be written as: Flow to Melton Hill Reservoir = Norris Dam outflow + Local inflow The flow to Melton Hill Reservoir is obtained from a mass balance on the reservoir at the downstream end of the study reach as: Daily Inflow = Total measured outflow for the period + change in storage over the period, i.e. Y Qin = E Qout + A Storage. Daily inflows and reservoir storage volumes were provided by the TVA for the 1973 and 2003 floods in the spreadsheet "meltonhillrev0.xls" (Attachment 1-2), as discussed in Sections 6.4 and 6.5. The daily Norris Dam outflow was obtained from the TVA in the spreadsheet "norris rev0.xls," provided with this calculation as Attachment 1-1. Local inflow is taken as the difference between the flow to the reservoir and the flow from Norris Dam. For the purposes of calculating effective rainfall or direct runoff volumes, base flow is estimated and subtracted from the local flow to obtain the direct runoff volume, which, when converted to inches, can be used as the CHKVOL parameter in FLDHYDRO. The water balance is shown in Table 3 and Figure 4 for the March 1973 flood (see calculations presented in the spreadsheet "Basin 27 Runoff Volume Calc.xls," presented as Attachment 1-5 to this calculation). The runoff originating in Subbasin 27 from the March 1973 flood is shown in red-in Figure 4. The local runoff increases, peaks, and recedes before inflow from Norris Dam (shown in light blue) has an impact. After the local runoff has passed below Melton Hill Dam, releases from Norris Dam ramp up to an approximately constant rate of about 16,800 cfs for several days. Subtracting the inflow from Norris Dam from the inflow hydrograph to Melton Hill (shown in yellow), which is determined from the mass balance, gives the local inflow, which from March 19 th forward is essentially base flow. Based on these flows, a reasonable duration for the local hydrograph is March 14 to 19, and base flow can be taken as linearly rising from 533 to 2,204 cfs. The separation of base flow from total inflow is shown graphically in Figure 5 and is summarized in Table 4. TVA Calculation No. CDQ000020080068 Melton Hill Local Watershed (Subbasin 27) Unit Hydrograph Validation Table 3: Daily Mass Balance for Subbasin 27 for the March 1973 Flood Melton H II Melton Hill Norris Dam Total local Direct local Vol Qout, cfs- Avolume, cfs- Inflow = AS + inflow, cfs- inflow, cfs- Base flow, cfs runoff, cfs- HW, ft kcfs-days days days Qout days days days days 12-Mar 793.59 56.50 1,948 400 2,348 0 2,348 2,348 0 13-Mar 794.00 57.63 0 1,130 1,130 0 1,130 1,130 0 14-Mar 793.88 57.30 918 -330 588 55 533 533 0 15-Mar 794.73 59.71 3,468 2,410 5,878 0 5,878 867 5,011 16-Mar 795.58 62.24 26,884 2,530 29,414 0 29,414 1,201 28,213 17-Mar 794.25 58.33 24,025 -3,910 20,115 0 20,115 1,536 18,579 18-Mar 793.15 55.32 9,455 -3,010 6,445 0 6,445 1,870 4,575 19-Mar 793.13 55.26 3,901 -60 3,841 1,637 2,204 2,204 0 20-Mar 793.94 57.46 9,814 2,200 12,014 8,769 3,245 3,245 0 21-Mar 793.23 55.53 17,403 -1,930 15,473 12,904 2,569 2,569 0 22-Mar 794.21 58.22 18,450 2,690 21,140 16,851 4,289 4,289 0 23-Mar 794.15 58.05 20,900 -170 20,730 16,857 3,873 3,873 0 24-Mar 793.40 55.99 22,291 -2,060 20,231 16,810 3,421 3,421 0 25-Mar 793.00 54.92 21,354 -1,070 20,284 16,807 3,477 3,477 0 26-Mar 793.27 55.64 19,407 720 20,127 16,732 3,395 3,395 0 27-Mar 793.50 56.26 19,042 620 19,662 16,705 2,957 2,957 0 35,000 30,000 25,000 .• 20,000 15,000 10,000 5,000 0 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 Time in Days, starting March 12,1973 --- Melton Hill Qout, cfs-days Melton Hill Inflow = AS + Qout --x-- Norris Dam inflow, cfs-days ---- Total local inflow, cfs-days Figure 4: Daily Flow Series for Subbasin 27 for the March 1973 Flood TVA Calculation No. CDQ000020080068 Rev: 0 Plant: GEN Page: 20 Melton Hill Local Watershed (Subbasin 27) Unit Hydrograph Validation Prepared T.H.J Checked M.C.C 35,000 30,000 25,000 6 20,000 15,000 10,000 5,000 0 3/14/1973 3/15/1973 3/16/1973 3/17/1973 3/18/1973 3/19/1973 Time, days - Total local inflow, cfs-days -a- Base flow, cfs-days --- Direct local runoff, cfs-days Figure 5: Base Flow Separation for March 1973 Flood Table 4: Calculation of Direct Local Runoff Volume for Subbasin 27 for March 1973 Flood Total local inflow, Base flow, cfs- Direct local runoff, cfs-davs davs cfs-d a ys 3/14/1973 533 533 0 3/15/1973 5,878 867 5,011 3/16/1973 29,414 1,201 28,213 3/17/1973 20,115 1,536 18,579 3/18/1973 6,445 1,870 4,575 3/19/1973 2,204 2,204 0 7 of DLRO = 56,378 cfs-days 3 86,400 sec/day x cfs-days = 4,871,059,200 ft 2 Subbasin area = 431.9 mi 2 12 "/ft x Vol, ft3 ÷ (sq. mi. x [5280 ft/mi] )= 4.85 inches The mass balance developed to estimate the volume of local direct runoff for the May 2003 flood is shown in Table 5 and Figure 6 (see calculations presented in the spreadsheet "Basin 27 Runoff Volume Calc.xls," presented as Attachment 1-5 to this calculation). TVA Calculation No. CDQ000020080068 Melton Hill Local Watershed (Subbasin 27) Unit Hydrograph Validation Table 5: Daily Mass Balance for Subbasin 27 for the May 2003 Flood Melton Hill Vol Cout, cfs- Avolume, cfs-days Melton Hill Inflow Norris Dam Total local inflow, Base flow, cfs- Direct local runoff, Day HW, ft kcfs-days days AS + Qout inflow, cfs-days cfs-days days cfs-days Day ~~~~~~days ______29-Apr 793.70 56.79 8,000 -1,171 6,829 6,251 578 578 0 30-Apr 793.56 56.40 6,715 -385 6,330 5,202 1,128 1,128 0 1-May 793.48 56.18 5,666 -218 5,448 4,769 679 679 0 2-May 793.56 56.40 4,628 218 4,846 4,761 85 85 0 3-May 793.38 55.91 5,905 -490 5,415 4,751 664 664 0 4-May 793.99 57.59 3,664 1,681 5,345 4,757 588 588 0 5-May 793.81 57.09 7,295 -502 6,793 4,708 2,085 798 1,287 6-May 794.16 58.07 7,849 980 8,829 1,712 7,117 1,009 6,108 7-May 792.86 54.52 8,973 -3,551 5,422 211 5,211 1,219 3,992 8-May 794.28 58.41 549 3,891 4,440 714 3,726 1,429 2,297 9-May 793.87 57.26 3,628 -1,153 2,475 684 1,791 1,639 152 10-May 793.84 57.17 2,819 -84 2,735 675 2,060 2,060 0 11 -May 794.06 57.79 2,136 615 2,751 678 2,073 2,073 0 12-May 793.27 55.61 6,979 -2,175 4,804 5,774 -970 -970 0 13-May 793.31 55.72 10,985 108 11,093 9,376 1,717 1,717 0 14-May 793.84 57.17 8,842 1,452 10,294 8,720 1,574 1,574 0 15-May 794.73 59.71 7,340 2,532 9,872 6,906 2,966 2,966 0 16-May 794.09 57.87 8,100 -1,832 6,268 4,633 1,635 1,635 0 12,000 10,000 8,000 MLM 6,000 O 4,000 CE 0I 2,000 0 -2,000 Time in Days, starting 29 April 2003 -- *- Melton Hill Qout, cfs-days Melton Hill Inflow = AS + Qout -x- Norris Dam inflow, cfs-days - Total local inflow, cfs-days Figure 6: Daily Flow Series for Subbasin 27 for the May 2003 Flood TVA Calculation No. CDQ000020080068 Rev: 0 Plant: GEN Page: 22 Melton Hill Local Watershed (Subbasin 27) Unit Hydrograph Validation Prepared T.H.J Checked M.C.C The total local inflow for Subbasin 27 is shown in red in Figure 6. The separation of base flow from total inflow is shown graphically in Figure 7 and is summarized in Table 6. 8,000 7,000 6,000 ,•5,000 4,000 'A=3,000 2,000 1,000 0 5/4/2003 5/6/2003 5/8/2003 Time, days - Total local inflow, cfs-days - Base flow, cfs-days Direct local runoff, cfs-days Figure 7: Base Flow Separation for the May 2003 Flood Table 6: Calculation of Direct Local Runoff Volume for Subbasin 27 for May 2003 Flood -r *1' - Toted local inflow, Direct local runoff, cfs- cfs-days Base flow, cfs-days days 5/4/2003 588 588 0 5/5/2003 2,085 829 1,256 5/6/2003 7,117 1,069 6,048 5/7/2003 5,211 1,310 3,901 5/8/2003 3,726 1,550 2,176 5/9/2003 1,791 1,791 0 I of DLRO = 13,381 cfs-days 3 86,400 sec/day x cfs-days = 1,156,118,400 ft .2 Subbasin area = 431.90 ml 3 2 12 "ft x Vol, ft - (sq. mi. x [5280 ft/mi] )= 1.15 inches TVA Calculation No. CDQ000020080068 Rev: 0 Plant: GEN Page: 23 Melton Hill Local Watershed (Subbasin 27) Unit Hydrograph Validation Prepared T.H.J Checked M.C.C 7.2 Calculationof Effective PrecipitationSeries The effective (or excess) rainfall hyetograph is the series that is convoluted with the unit hydrograph to provide the direct runoff for each subbasin. This is developed from the observed rainfall hyetograph by the application of a loss rate function which accounts for the hydrologic abstractions of evaporation and transpiration, interception, depression storage, and infiltration (Reference 14). Effective rainfall is obtained from observed rainfall data with the FLDHYDRO program (Reference 5). The FLDHYDRO program was developed by the TVA to implement the Antecedent Precipitation Index (API)/Runoff Index (RI) methodology developed by the United States Weather Bureau, as described in Reference 3. In brief, the method uses the API for a given day, which is calculated on the basis of a recession constant normally reported to range from 0.85 to 0.98 (Reference 2, page 101). A recession constant of 0.9 is assumed for this calculation. The API is used to obtain a Runoff Index (RI) that has been determined for the Tennessee River Valley region as a function of precipitation, location, and season. The RI is then used to obtain precipitation losses for each increment of rainfall. The use of the loss function is discussed in the TVA White Paper (Reference 8), and the methodology is described in detail in the Kohler and Linsley United States Weather Bureau publication (References 2 and 3). Input to FLDHYDRO is via a column delimited batch file. Input includes: * Hourly and daily precipitation gage readings for the gridded precipitation data sets; daily precipitation depths were calculated by summing hourly rainfall depths. * Indices to relate each non-recording gage record to a recording gage record for interpolation * Thiessen coefficients to weight gage records for the calculation of basin average precipitation depths (not used for gridded precipitation data) " Depth of runoff for the period of rainfall For this calculation, input for each run included the following data and "flags": " NARFE = 1 to obtain a printout of flood hydrographs only " NRI = 1 for the number of Rainfall Runoff Indices to be used per basin * NCPTS = 1 for the number of sites for surface runoff volume check (set to zero if a runoff check volume is not supplied) * NSUBW = 1 for number of sub-watershed (Subbasin 27) * NREC = 2 for the number of recorders (using only one time series per basin as one "recorder") * NSTNS = 2 for total number of stations (i.e. no non-recording stations used) " STAB = 2 when API areas vary with watershed " ITDGR = 0 for the hour at which each gage is read * NAMSTA = The name of each recording gage (name of subbasin for this application) * BEGDR = The starting date (entered in MMDDYY format) " BEGTR = Time at which the first hour of rainfall has been recorded (between 01 to 24) * NHR = The number of hourly readings for the storm " SHRAIN = The time series of hourly rainfall readings (in 10F8.0 format) obtained from processing of NWS gridded rainfall TVA Calculation No. CDQ000020080068 Rev: 0 Plant: GEN Page: 24 Melton Hill Local Watershed (Subbasin 27) Unit Hydrograph Validation Prepared T.H.J Checked M.C.C " NDRAPI = The number of days of antecedent rainfall listed before the storm * API = The initial API at the beginning of the antecedent daily rainfall series (setting this value to 1.0 is sufficient when a month of data is used because the initial condition has negligible impact on the final API for a sufficiently long series) * APRAIN = The time series of daily rainfall readings (in 10F8.0 format) obtained from the sum of hourly rainfall data for approximately one month prior to the start of the hourly rainfall * BAREA = The subbasin area in square miles * APITYPE = The API zone with SE = 1, E = 2, NE = 3, N = 4, W = 5, and S = 6. Subbasin 27 is assumed to be in the N zone (see Figure 8). * NSPW = 1 for number of rainfall stations for each sub-watershed (for gridded data there are no Thiessen weighting factors) * NUM VOL = Number of watersheds above surface runoff volume check point " CHKVOL = The volume of surface runoff in inches (calculated from outflow hydrographs after base flow separation) Figure 8: API Regions for Application of TVA FLDHYDRO Program TVA Calculation No. CDQ000020080068 Rev: 0 Plant: GEN Page: 25 Melton Hill Local Watershed (Subbasin 27) Unit Hydrograph Validation Prepared T.H.J Checked M.C.C Input and output files from the FLDHYDRO runs are provided for the March 1973 and May 2003 floods as the following attachments: * Basin27-1973.dat, included as Attachment 2-3 " Basin27-1973.out, included as Attachment 2-4 * MHReservorl 973.dat, included as Attachment 2-5 * MHReservoir1973.out, included as Attachment 2-6 " Basin27-2003.dat, included as Attachment 2-7 * Basin27-2003.out, included as Attachment 2-8 As noted in Section 6.6, two separate rainfall data sets were provided. Separate FLDHYDRO runs were provided by the TVA for the 1973 event for the subbasin area and the reservoir area. A total runoff volume of 4.85 inches was used as input for both of these runs, but the rainfall inputs utilized different Theissen weighting factors because of the difference in areal coverage. For the May 2003 event, grid-based precipitation data were used with a total runoff volume of 1.15 inches. A single basin-wide average precipitation depth was used for the simulation of the reservoir and total subbasin area, without differentiation. The cumulative precipitation and excessive rainfall (runoff) depths calculated in FLDHYDRO for the March 1973 storm for the total basin and for the reservoir area are plotted in Figure 9, from which it can be seen that there is not a significant difference in the depths. The cumulative precipitation and runoff depths for the May 2003 event are plotted in Figure 10. Calculations are provided in the spreadsheet "Basin 27 Effective PPT.xls," provided as Attachment 1-4. 8 7 -- 0) (U44 0 0 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 Time, in hours -s Rainfall from subbasin = Runoff on Subbasin A Rainfall over reservoir --- "Runoff from Reservoir Figure 9: Cumulative Precipitation and Runoff Series for March 1973 Event in Subbasin 27 TVA Calculation No. CDQ000020080068 Rev: 0 Plant: GEN Page: 26 Melton Hill Local Watershed (Subbasin 27) Unit Hydrograph Validation Prepared T.H.J Checked M.C.C 4 3 0 2 E10 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58 61 64 67 70 Time, hours --- rainfall - runoff Figure 10: Cumulative Precipitation and Runoff Series for May 2003 Event in Subbasin 27 7.3 Calculation of Additional Runoff on Melton Hill Reservoir The SOCH model requires as input the runoff resulting from the total rainfall over the reservoir area, measured as 8.74 square miles (Reference 10). The local runoff hydrograph accounts for only the effective rainfall over the entire subbasin, including the reservoir area. Therefore, the additional volume generated by rain falling on the reservoir surface, over and above that convoluted with the unit hydrograph, must be added. This volume is obtained by taking the depth of observed rainfall on the reservoir area minus the depth of direct runoff calculated in FLDHYDRO, and multiplying it by the reservoir surface area. The surface area of Melton Hill Reservoir varies with time, in response to changing volumes in storage. Using the stage-area data shown in Figure 1, it was determined that the maximum change in reservoir surface area during the period of rainfall for the March1973 period was about 10 percent, and about 6 percent for the May 2003 flood. Considering the small variation in the reservoir area in relation to the total subbasin area, the reservoir surface area was taken as a constant 8.74 square miles for the calculation of runoff from rainfall over the reservoir to be consistent with the TVA's calculations. The flow series obtained from the abstracted rainfall over the reservoir area was calculated in HEC- HMS, as described in next section. TVA Calculation No. CDQ000020080068 Melton Hill Local Watershed (Subbasin 27) Unit Hydrograph Validation 7.4 HEC-HMS Simulations of Flood Events A HEC-HMS project file was developed to generate local inflow hydrographs for Subbasin 27 using the unit hydrograph for the Melton Hill Dam subwatershed to provide inputs for the SOCH model of the Tennessee River for the March 1973 and May 2003 floods, as described below. This project file has been compressed into a zip file to preserve the folder structure and has been stored in FILEKEEPER (Attachment 3-1 ). The HEC-HMS model schematic for the 1973 and 2003 simulations is shown in Figure 11. Subbasin27 Reservoir Total Inflow Figure 11: HEC-HMS Schematic Watershed Model for the Melton Hill 1973 and Melton Hill 2003 Simulations The following input files were developed for the project and input to HEC-HMS (References 12 and 13) via the Time Series Data Manager (For this calculation, all time series are adjusted to Central Time): 0 Precipitation Gage "March73EffectivePPT" with hourly data incremental depths 0 Precipitation Gage "March73RainOnReservoir" with hourly data incremental depths 0 Discharge Gage "May2003EffectivePPT" with hourly data incremental depths 0 Discharge Gage "May2003RainOnReservoir" with hourly data incremental depths Note that instead of inputting observed basin average precipitation and utilizing a loss function for the subbasin, the effective basin average rainfall (or runoff) output from FLDHYDRO was utilized as "precipitation data." The rain-on-reservoir files were developed from the abstracted rainfall series, developed by subtracting the effective rainfall calculated in FLDHYDRO from the total rainfall on the reservoir area. TVA Calculation No. CDQ000020080068 Rev: 0 Plant: GEN Page: 28 Melton Hill Local Watershed (Subbasin 27) Unit Hydrograph Validation Prepared T.H.J Checked M.C.C The unit hydrograph for the Melton Hill Dam subbasin was input to HEC-HMS with the Paired Data Manager (Reference 12) as UH27. Local runoff from Subbasin 27 for the land mass and reservoir area is calculated in the model by convolution of the effective rainfall time series with the unit hydrograph developed for the subbasin at the node labeled "Subbasin27" (see Figure 11). The runoff for the additional rainfall over the reservoir is calculated in the model by multiplying the abstracted rainfall series by the reservoir area at the node labeled "Reservoir" (see Figure 11). The direct inflow is obtained by adding the hydrographs developed at nodes Subbasin 27 and Reservoir at the node labeled "Total Inflow" in Figure.1 1. Model results for direct runoff for the 1973 and 2003 floods, respectively, are shown graphically for the Total Inflow node in Figures 12 and 13. By adding base flow to the time series developed for the total inflow node, the total inflow series was developed in the spreadsheet "Total Local Hydrograph Development.xls," provided as Attachment 1-6 and in Figures 14 and 15 for the March 1973 and May 2003 floods, respectively. Tabulated values of the total runoff time series output from HEC-HMS are provided in Attachment 1-6. TVA Calculation No. CDQ000020080068 Rev: 0 Plant: GEN Page: 29 Melton Hill Local Watershed (Subbasin 27) Unit Hydrograph Validation Prepared T.H.J Checked M.C.C Junction "Total Inflow" Results for Run "March1973" 20,000- E 15,000" 10,000- 5,000- -5,00014 15 16 1'7 1,8 19 20 2'1 22 2 3 Marl1973 Legend (Compte T*-e0 Z3Apx2009, 10:30:04) Run:MARCH973 Bemerm:TOTALINFLOW Reuft:Outfiow - - - Run:o mh1O73Bemer4:Resereoir Result:Oztflow RunAMemhI73--- Bee,.nt:Subbasin27 Result:Oufiom Figure 12: HEC-HMS Output for Total Inflow Node for Simulation of March 1973 Flood Junction 'Total Inflow" Results for Run "May2003" 8,000 7,000- 6,000- 5.000- u- o4.000- u-A 5 6 7 8 9 10 May2C Legend (CoepoAe Thee: 23Apr2009, 09:01:21) - Run:Iy2003 8-ement:TOTA INFLOWRennAt:OutfWoI - - - R.n:Iay2003 Bemenn:Reservoir RNsuit:Otfl-o ....- Ro:y2OO3 BemntM:0obb.5in2? R.stt:Ootfl-o Figure 13: HEC-HMS Output for Total Inflow Node for Simulation of May 2003 Flood TVA Calculation No. CDQ000020080068 Rev: 0 Plant: GEN Page: 30 Melton Hill Local Watershed (Subbasin 27) Unit Hydrograph Validation Prepared T.H.J Checked M.C.C 50,000 45,000 40,000 35,000 30,000 25,000 U 20,000 (A 15,000 10,000 5,000 0 0 24 48 72 96 120 144 168 192 216 240 Time in hours from March 14, 1973 0:00 hrs CST - Reservoir Inflow, cfs Subbasin 27 Inflow, cfs Total Direct Runoff, cfs ----- Base Flow, cfs -. Total Runoff, cfs Figure 14: Development of Subbasin 27 Total Local Inflow Hydrograph for March 1973 Flood 9,000 8,000 7,000 6,000 a" 5,000 ." 4,000 a 3,000 2,000 1,000 0 0 24 48 72 96 120 144 Time in hours from May 5, 2003 0:00 hrs CDT Reservoir Inflow, cfs ---- Subbasin 27 Inflow, cfs Total Direct Runoff, cfs -- *-- Base Flow, cfs --- Total Runoff, cfs Figure 15: Development of Subbasin 27 Total Local Inflow Hydrograph for May 2003 Flood TVA Calculation No. CDQ000020080068 Rev: 2 Plant: GEN Page: 31 Melton Hill Dam Local Watershed (Subbasin 27) Unit Hydrograph Prepared HLSS Checked BH 7.5 SOCH Model Input Two time series were provided for use in the SOCH models for the March 1973 and the May 2003 validation runs. These inputs are as follows: * Total direct runoff for Subbasin 27, * Losses and runoff for.Subbasin 27. The time series were developed in spreadsheets in Attachments 1-1 and 1-2. Plots of the component time series are provided as Figures 4 through 7 in Section 7.1. 7.6 SOCH Model Output and Unit Hydrograph Validation The component time series presented in Sections 7.4 of this calculation were used as inputs to a SOCH model of the reach of the Clinch River between Norris and Melton Hill Dams. For the March 1973 event, simulated and observed water surface elevations were compared at two gage locations, Clinch River Miles 79.8 and 58.8. For the May 2003 event, simulated and observed water surface elevations were compared at gage location Clinch River Mile 79.8. Simulated and observed discharges were compared at Clinch River Mile 23.1 for both historic floods. As described in Calculation CDQ000020080038 Rev 0 (Reference 17), local inflows to Melton Hill Reservoir from Subbasin 27 were combined with the observed data (Norris observed discharge and tailwater elevation, and Melton Hill observed discharge and headwater elevation) for the March 1973 and May 2003 events and conservatively reproduced the observed peak elevations at gage locations along the reservoir for historic floods. Additionally, the SOCH model accurately replicated the observed discharges for the two large historic flood events within a reasonable margin. These comparisons are shown in Figures 16 through 19. As a result, the unit hydrograph developed for Subbasin 27 was validated and deemed adequate for use in developing flood inflows for other events, including PMF. Data and simulation results for the aforementioned figures are provided in Attachments 4-1 and 4-2. TVA Calculation No. CDQ000020080068 Rev: 2 Plant: GEN Page: 32 Melton Hill Dam Local Watershed (Subbasin 27) Unit Hydrograph Prepared HLSS Checked BH 830 -- Observed Clinch River at Norris TW CRM 79.8 825 r -- Observed Clinch 820 :1 River at Clinton, TN CRM 58.8 815 ,-J ComputedC Clinch River at Norris TW )810 CRM 79.8 0 805 14. CComputed Clinch LL River at Clinton, C TN CRM 58.8 r8 00 Observed Clinch River at Melton Hill W 795 -~~-: Headwater (Downstream Boundary) CRM 23.1 790 ...... 3/14/73 3/15/73 3/16/73 3/17/73 3/18/73 3/19/73 3/20/73 3/21/73 3/22/73 Date Figure 16: Observed and Simulated Stage Hydrographs for the Clinch River between Norris and Melton Hill Dams, March 1973 TVA Calculation No. CDQ000020080068 Rev: 2 Plant: GEN Page: 33 Melton Hill Dam Local Watershed (Subbasin 27) Unit Hydrograph Prepared HLSS Checked BH 70 60 50 40 V) 0U. 0 0 0 30 °C 0 20 10 0 +- 3/14/73 3/15/73 3/16/73 3/17/73 3/18/73 3/19/73 3/20/73 3/21/73 3/22/73 Date Figure 17: Observed and Simulated Discharge Hydrographs at Melton Hill Dam, March 1973 TVA Calculation No. CDQ000020080068 Rev: 2 Plant: GEN Page: 34 Melton Hill Dam Local Watershed (Subbasin 27) Unit Hydrograph Prepared HLSS Checked BH 830 825 -- Observed Clinch 820 River at Norris TW CRM 79.8 815 -J =E 0 810 Observed .02 Clinch River at Melton Hill 805 HW CRM 23.1 II-0 0 800 u.2 Computed Clinch 795 River at Norris TW CRM 79.8 790 5/3/ 03 5/5/03 5/7/03 5/9/03 5/11/03 5/13/03 5/15/03 5/17/03 Date Figure 18: Observed and Simulated Stage Hydrographs for the Clinch River between Norris and Melton Hill Dams, May 2003 TVA Calculation No. CDQ000020080068 Rev: 2 Plant: GEN Page: 35 Melton Hill Dam Local Watershed (Subbasin 27) Unit Hydrograph Prepared HLSS Checked BH 40 35 30 25 en IL 0 •S- 15 0 15. 10 5 0 4- 5/3/03 5/5/03 5/7/03 5/9/03 5/11/03 5/13/03 5/15/03 5/17/03 Date Figure 19: Observed and Simulated Discharge Hydrographs at Melton Hill Dam, May 2003 TVA Calculation No. CDQ000020080068 Rev: 1 Plant: GEN Page: 36 Melton Hill Dam Local Watershed (Subbasin 27) Unit Hydrograph Prepared HLSS Checked BH 8 Conclusions The unit hydrograph for Subbasin 27 for the simulation of local inflow to the Tennessee River between Norris and Melton Hill Dams was developed by TVA previously. In compliance with NRC requirements, the unit hydrograph was indirectly validated in this calculation for two events: the floods of March 1973 and May 2003. The usual procedure for validating local unit hydrographs is to use them to develop flow series for observed rainfall inputs and compare them with check series developed from reverse reservoir routing and hydrograph separation, as required. The original unit hydrograph was developed by this method. To validate the unit hydrograph local runoff hydrographs were developed from observed rainfall series for the 1973 and 2003 floods for use as input to the SOCH model simulation of the reach of the Clinch River between Norris and Melton Hill Dams for SOCH calibration and unit hydrograph validation. 8.1 Unit Hydrograph Validation The original unit hydrograph in 6.2 for Subbasin 27 was indirectly validated for the March 1973 and May 2003 floods in this calculation and are provided in Table 7 (Attachment 4-3). Since the stage and discharge hydrograph simulated in the SOCH model runs utilizing local inputs developed with the unit hydrograph conservatively predicts observed data, it is concluded that the original unit hydrograph adequately describes the response of the local catchment area between the reservoirs and is valid for use in hydrologic studies to determine PMF. Table 7: Validated 6-hour Unit Hydrograph Ordinates for Subbasin 27 Hour Q, cfs Q, avg cfs Volume, Ac-ft 0 0 6256 3107 6 12530 11348 5627 12 10165 9008 4467 18 7850 6624 3284 24 5397 4171 2068 30 2945 2655 1316 36 2364 2073 1028 42 1782 1492 740 48 1201 910 451 54 619 569 282 60 519 469 232 66 418 368 182 72 318 268 133 78 218 168 83 84 117 59 29 90 0 0 0