SDA-1116-034770 - Proposed nbn Facility at 23 Jirrima Cres Cooroibah - Response to Information Request

are to be left in the ground to aid in stabilisation. If deep excavation is required during construction
the roots may only be removed within the construction footprint area under this code.”

Please provide further information on this aspect of the development and how the development will
not increase the risk to fisheries resources if this requirement cannot be met.

Minor vegetation clearing is required as part of the culvert replacement. The vegetation required to be
removed at the roots will be contained wholly within the construction footprint, to allow for construction of
the foundation of the new culvert. The extent of the vegetation to be cleared is shown in the Photographs
attached within Appendix C.

All other vegetation clearing will comply with Section 5.1.6 of the self-assessable code WWBW01-Part 3:
Culvert Crossings, in that it will not be cut below ground level. This minor clearing is not considered to
constitute a significant risk to fisheries resources.

3. PO4 – response to AO4.2 of SDAP Module 5.2; If the barrier remains in place, fish passage
provision in accordance with the approved design and operation is maintained as long as the barrier
remains.

Please detail how the culvert will be maintained so that the fish passage features of the structure
(e.g. low flow channel and culvert cells) remain navigable by fish (i.e. not silted up or block by
debris).

The following measures will be incorporated into the culvert design so that the fish passage features of the
structure remain navigable by fish:

        •   Steps and drops in elevation across the bed gradient will be eliminated to provide a level fish
            crossing;
        •   The culvert will be installed at approximately 550mm below bed level;
        •   The culvert will be backfilled with bed material won from the site to maintain and simulate natural
            bed surface;
        •   The culvert will be installed at a minimum of 1200mm wide to allow for fish passage; and
        •   The proposed culvert will increase the cell cross-sectional area of the existing culvert
            configuration.

4. PO10 – Offsets.

Without detailed designs of the culvert crossing, it cannot be determined whether the proposed
development will result in a significant residual impact to fish passage. Please provide detailed
design drawings including information on the design features incorporated into the culvert design
that have been utilised to allow for fish passage through the structure. Refer to the DILGP Significant
Residual Impact Guideline – section 3.8 “Waterways providing for fish passage” to determine if a
significant residual impact is expected.

Please refer to Appendix B for detailed design drawings of the proposed culvert replacement.

The proposed culvert replacement will not result in a significant residual impact to fish passage given the
following:




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