Final Engineering services report _62 Lake Macdonald Drive · OPW25/0057

                                                                                        Flood Hazard Assessment
                                                               Intersection of Lake Macdonald Dr and Dianella Crt



3        SITE CHARACTERISTICS
The subject site is the intersection of Lake Macdonald Dr and Dianella Ct in Cooroy.

Detailed ground and feature survey provided by Murray & Associates shows three pipe culvert cells
passing beneath Lake Macdonald Dr from the southeast corner of the intersection with Dianella Ct
to the northwest corner of the intersection adjacent to Wilgee Ct. Two of pipe culverts are shown to
be 1050 mm diameter and the third is 1350 mm diameter.

The Swift Drive culvert is a 1350 mm diameter and the Curlew Crs crossing is a 750 mm diameter.

Invert levels for these pipe culverts were determined from the 2022 digital elevation model (DEM).

3.1 Catchment Characteristics
Upstream of the subject site, the local catchment extends to the southeast and northeast and covers
an area of approximately 70 hectares. The catchment is comprised of three sub-tributaries. The
larger two of these sub-tributaries have a confluence downstream of Swift Dr and Curlew Crs. A third
minor tributary drains from southwest and joins the main tributary watercourse approximately 450
m upstream of the subject site. There is also a minor inflow to the main tributary from the north just
upstream of the subject site. The tributary waterway corridor is well defined by adjacent elevated
topography.




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