2014-11-17 General Committee Agenda

GENERAL COMMITTEE MEETING AGENDA   17 NOVEMBER 2014




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GENERAL COMMITTEE MEETING AGENDA                                                                 17 NOVEMBER 2014

                e   checking the detailed design of the culverts with respect to gradients, inverts, inlet and outlet
                    aprons, etc.
                e   checking of the fish passage proposal.
                | would like to note that upon reviewing my files it appears likely that | had in fact inspected this
                culvert during a general site inspection of various waterways in the Noosa Council area in the
                company of council officer Dave Burrows on 4 December 2013. The culvert and creek
                conditions on that date are presented in figures 1 and 2.
                 Tee Ta         CO aces                        se  ‘            P
                :      ee                     :                                 ‘                      mS,
                  ee                                   SF              ee.

                ’                         woes   pieuter ane"    :    an      .      Ponies wt.
                o             Vi       Fagg          eee)       ee                  0        eee         eae
                 ;                 rt      REE                   Bf Be ee
                ¥                   We             =     SRR      ASA   ge meee eee,
                      y             F ¢ bers             Ws       MONG   PO    ee     eee    > | ca
                     \         Pr eg oe                    Th    LPG  vs ae          a             ee vi
                     ,               EPP a               Baus      Weed era       7 ae         As     \
                               Poi Sta   . =              iy    LS  RS: ee            fe  See ee       q
                           Figure 1 — Culvert inlet            Figure 2 — Looking upstream from culvert

                Relevance of my experience to this subject
                 | believe it to be relevant at this point to outline aspects of my work experience that allows me
                to conduct this review and provide the enclosed recommendations.
                e   |am the principal author of the revised Queensland Urban Drainage Manual (QUDM)
                    editions of 2007 and 2013.
                e   |am one of the primary authors of the Australian Rainfall and Runoff, Project 11 Stage 2
                    report, ‘Blockage of Hydraulic Structures’, and the author of the ‘Scheme B’ method of
                    assessing design blockage conditions.
                e   | was a development assessment officer (stormwater) for Brisbane City Council during
                    the periods 1991 to 1994, and 1995 to 1997.
                 Recommendations on the selection of a ‘design’ blockage factor
                There are several blockage conditions that should be considered at this site, those being:
                 e  A ‘design’ blockage condition applied to the design of the culvert and road floodway
                    (overtopping flows). This blockage condition should represent the ‘AEP neutral’ condition,
                    that is, the ‘average’ blockage condition expected during the nominated design storm.
                 e  A ‘severe’ blockage condition that may be applied to a lesser design storm. This blockage
                    condition represents an extreme blockage condition that is considered possible, but unlikely
                    to occur on a regular basis during a particular design storm (i.e a non AEP-neutral
                    condition). For example, if a 20% blockage condition is adopted as the ‘design’ blockage
                    condition for a 10% AEP (1 in 10 year) design storm, then it may be considered reasonable
                    to check the flow conditions for a ‘severe’ blockage condition during the 63% AEP (1 in 1
                    year) storm.
                 e  A ‘severe’ blockage condition can also be used to check the suitability of the nominated
                    freeboard of habitable floor levels. However, it should be noted that currently it is not normal
                    practice for this design check to be performed. In any case, this design philosophy is based
                 Printed: 06 November 2014        CREEKS: CORRIDORS OF OPPORTUNITY                  Page 2.

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