Lower Byersville Creek Flood-Risk Mapping Update - City of ...

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GOLFVIEW RDWEBBER AVRALPHSON CRWENTWORTH ST1+025 - 190.71ARTHUR AVGOODFELLOW RDWIGHTMAN AVROBERT RD0+725 - 190.41WESTERN AVFORD STERSKINE AV0+543 - 190.410+543 - 190.410+384 - 190.41HIGH STSHIRLEY AVMONAGHAN RDKENT STWHITEFIELD DRTHE PARKWAYCLONSILLA AV2+031 - 192.671+800 - 192.332+332 - 195.72+148 - 192.911+565 - 191.73SILVERDALE RD2+275 - 192.922+031 - 192.672+662 - 195.252+512 - 195.242+332 - 195.222+148 - 192.911+845 - 192.66RYE ST2+506 - 195.231+800 - 192.333+025 - 195.482+917 - 195.731+845 - 192.663+645 - 200.382+961 - 195.732+883 - 195.732+662 - 195.722+275 - 192.922+512 - 195.713+390 - 196.721+346 - 191.443+165 - 196.243+073 - 196.152+917 - 195.33+554 - 198.78 3+554 - 198.782+703 - 195.72Costco1+305 - 191.081964 - 193.511+565 - 191.731+187 - 190.891950 - 193.333+390 - 196.722+961 - 195.321882 - 192.82050 - 1962+703 - 195.261978 - 1961800 - 192.751850 - 192.781763 - 192.631700 - 192.611610 - 192.531458 - 192.351+705 - 191.981+346 - 191.443+165 - 196.243+073 - 196.153+025 - 195.75CAMERON PL1+527 - 191.522+883 - 195.291+705 - 191.98STORNOWAY PLARTHUR AVCROWN DRTHE KINGSWAY1+527 - 191.527 & 115 HY0+865 - 190.561800QUEENSWAY CTMOUNTAIN ASH RDCHAMBERLAIN PLST MARY'S ST1405 - 192.15THE QUEENSWAY14051327 - 192.090+450 - 191.241250 - 192.050+400 - 191.150+350 - 191.020+300 - 190.960+250 - 190.870+200 - 190.620+150 - 190.460+100 - 190.37BARNES CRSTOCKER RDCHAMBERLAIN STDUFFUS ST0+450 - 191.241777 - 192.74BRUNSWICK AVNEW ROMAINE STBORDEN AVGRADY AV1428 - 192.16BROWN ST0+384 - 190.41CRAWFORD PLLansdownePlaceGILLESPIE AVORPINGTON RDBARBARA CRST MARY'S STCAMERON STCRAWFORD DR0+223 - 190.410+223 - 190.41HAWLEY STFRANK STCHAMBERLAIN STBROWN STLUNDY'S LNLITTLE STMERVIN AVBELLAIRE STHAROLD DRNOBLE PLROMAINE ST0+055 - 190.410+083 - 190.41Cross SectionsLabels0+083 - 190.410+021 - 190.410+055 - 190.41ALBERT STNew XCG CNRSpill ModelUpdated DMWills ModelUpdated ORCAModelDOUGLAS AVMCCANNAN AVFAGAN AVHOWDEN STSPRUCE AVALFRED STBRAUND PLStation - Water Surface Elevation (m)Water Depth (m)0 - 0.010.01 - 0.050.05 - 0.10.1 - 0.20.2 - 0.30.3 - 0.40.4 - 0.50.5 - 0.60.6 - 0.70.7 - 0.80.8 - 0.90.9 - 11.0 - 1.51.5 - 22.0 - 2.52.5 - 33.0 - 3.53.5 - 44.0 - 4.54.5 - 5PRISCILLA STCurrent RegulatoryFlood Risk Lineper ORCASTEELE AVRIVERSIDE DR7 & 115 HYJOHNSTON DRGUTHRIE DRFigure 3.4Regional Storm Event with ProposedCPR Culvert Replacement (ModellingCase 4) Surface FloodingË0 100 200 300 400MetersNote:1. Elevation data used in the analysis is based on the Digital Elevation Model(DEM) provided by the City of Peterborough dated 2005. All ground elevationsare based on the DEM with the exception of the Costco and Lansdowne Placeproperties which have been developed since then. Site grading plans for the twoproperties were used to modify the DEM to more accurately represent thedevelopments. Site grading plan for Costco property by MMM Group, datedFeb.13, 2008. Site grading plan for Lansdowne Place by CounterpointEngineering dated June 4, 2008.
City of PeterboroughLower Byersville Creek Flood-Risk Mapping UpdateLIMITATIONS OF ANALYSIS4. LIMITATIONS OF ANALYSIS4.1 Limitations of Modelling ApproachAs described above, the modelling approach has been based on the use of EXTRANfor dynamic flow routing and computation of how much flow travels along variousflow paths within the subject area. HEC-RAS has then been used in “steady state”mode to compute water surface elevations associated with the peak flows computedby EXTRAN.This approach accounts for the considerable surface storage effects that are presentwithin the subject area, along the main stem of Byersville Creek itself, and withinother area subject to surface ponding or flooding. Additionally, this approachaccounts for capacity limitations of the storm sewer system and represents the factthat surcharging of pipe systems such as the Erskine Avenue storm sewer may havecontributed to surface flow along streets such as Erskine Avenue.The modelling approach is considered to be a reasonable representation of thesystem, considering the favourable reproduction of what occurred during the eventof July 2004. However, it needs to be recognized that the modelling tools that havebeen applied are what is termed “one dimensional” models of open channel flow.The models have been applied such that a number of interconnected flow conduitshave been used to provide a presentation of what is in fact a very two-dimensionalsituation in which surface flow does not follow one well-defined floodway, butinstead bifurcates, flows along multiple surface paths, and then reconverges near thewatershed outlet.While the modelling approach is considered a reasonable approximation, it needs tobe realized that it may not account for all localized flow patterns. Nonetheless, theresulting mapping of the area subject to surface flooding is considered to be acomprehensive mapping of where flooding risk exists, based on the availabletopographic base mapping.4.2 Base MappingThe topographic base mapping and the resulting mapping of flooded areas, is derivedfrom the digital elevation model (DEM) supplied by the City. The vertical precisionof the DEM is 0.25 m, having been reportedly derived from air photo interpretationin which a vertical accuracy of 0.16 m was achieved (per report to City ofPeterborough by OSI Geomatics, 2005).As noted above, the 0.25-m precision of the available topographic mapping isconsistent with technical guidelines for floodplain mapping that have previouslybeen published by the Ontario Ministry of Natural Resources ("Flood PlainManagement in Ontario: Technical Guidelines" , section "J - Surveys and MappingProcedures for Floodplain Mapping", Ont. Ministry of Natural Resources, 1986).3-2087-09-01/R_3-04108226_Byersville Creek Mapping Update 4-108/11/10
Page 1 and 2: EXCELLENCE INENVIRONMENTALCONSULTIN
Page 3 and 4: City of PeterboroughLower Byersvill
Page 25: WEBBER AVRALPHSON CRWENTWORTH ST1+0
Page 33 and 34: APPENDIX A: PHOTOS PROVIDED TO XCG
Page 43 and 44: February 9, 2010Dear Resident,XCG C
Page 45 and 46: MOUNTAIN ASH RDBARNES CRROBERT RDER
Page 47 and 48: ResponseNo.XCG file 3‐2087‐09
Page 49 and 50: XCG file 3-2087-09-01 APPENDIX B Pa
Page 53 and 54: C.2.1 Subcatchment Refinements:Refi
Page 55 and 56: FIGURE C-2: SCHEMATIC OF MODIFIED P
Page 57 and 58: For the Regional Storm, the event r
Page 59 and 60: Photo date May 28, 2007Photo date M
Page 61 and 62: WEBBER AVRYE STMOUNTAIN ASH RDROBER
Page 65 and 66: FIGURE D-3 Examiner Ditch West Spil
Page 67 and 68: TABLE D-3HEC-RAS RESULTS for EVENT
Page 69 and 70: TABLE D-5HEC-RAS RESULTS for EVENT
Page 71 and 72: TABLE D-7HEC-RAS RESULTS for REGION
Page 73 and 74: TABLE D-9HEC-RAS RESULTS for REGION
Page 75 and 76: TABLE D-11HEC-RAS RESULTS for REGIO
Page 77 and 78:
TABLE D-13HEC-RAS RESULTS for REGIO
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Lower Byersville Creek Flood-Risk Mapping Update - City of ...

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