Storm Water management plan · MCU12/0133.03

Noosa Council documents


                  Bligh Tanner Consulting Engineers                                                                            Page 14
                  Noosa Flexi Learning Centre Stormwater Management Plan
                  August 2012



                  5 HYDROLOGIC ASSESSMENT
                  5.1 Flooding of the site
                  The site is located at the top of a dune system with a very small external catchment (0.3 ha)
                  and on sandy, free draining soils. The site is therefore not prone to flooding. The site is well
                  clear of Council’s estimated food extent for the 100 year average recurrence interval (ARI)
                  flood1.

                  Under major storm events, runoff will flow across the site as sheet flow, as shown in Figure 5
                  below.

                  The central turfed area is intended for active recreation, and so it will be slightly raised to
                  assist with drainage so that the students can use this area sooner after it rains.




                             CATCHMENT
                             BOUNDARY




                                                                                       OVERLAND FLOW




                  Figure 5 Catchment boundary and overland flow paths


                  5.2 Flooding impacts downstream of the site

                  For the purposes of flood assessments, a 0.3 ha external catchment has been included (from
                  land immediately to the north of the site, and part of the adjoining lot to the east of the site,
                  refer Figure 5).

                  An initial sizing of flood detention has been undertaken using the initial sizing method
                  outlined in QUDM (2007) Section 5.05.1. For the developed case, the ground level fraction



                  1
                   Sunshine Coast Regional Council Estimated Flood Extent – 100 Year Average Recurrence Interval: Freshwater
                  Flooding And Storm Tide, Current Climate Conditions
                  http://www.sunshinecoast.qld.gov.au/addfiles/documents/floodmaps/ari_map_north.pdf last printed 24/03/2011



                                                                                                           Print Date: 2 March 2020, 2:19 PM