P0198-25-001_12_Gympie_Street_Tewantin_SWMP

Executive Summary
RECOR Consulting Engineers have been engaged by Novato Group to prepare a Stormwater Management Plan
(SWMP) to support a Development Approval Application for a proposed seven-lot residential subdivision at 12
Gympie Street, Tewantin.

This SWMP addresses the stormwater management strategy for the proposed development and demonstrates
compliance with the requirements of Noosa Shire Council, the Queensland Urban Drainage Manual (QUDM), and
Water by Design guidelines. The report outlines measures to ensure the development can be constructed and
operated in accordance with all relevant stormwater quantity and quality objectives.

Lawful Point of Discharge

Stormwater runoff from the development will be directed to a single lawful point of discharge via a stormwater
network into Council’s dedicated reserve to the north of the Butler Street Cul de sac. This configuration
consolidates site flows and ensures integration with existing downstream infrastructure. The discharge
arrangement has been verified through hydraulic modelling and is consistent with Council’s lawful discharge
requirements.

Stormwater Quantity

The hydrological assessment was undertaken using both the Rational Method and DRAINS modelling to establish
pre-development baseline conditions and to assess post-development impacts.

Results confirmed an increase in peak flow rates underdeveloped conditions due to added impervious surfaces.
To mitigate these effects, a bio-retention/detention basin is proposed within the north-eastern corner of the site.

Hydrological modelling confirms that post-development discharges remain equal to or below pre-development
flows across all assessed Annual Exceedance Probability (AEP) storm events, refer to section 3.3.

Stormwater Quality

A stormwater quality assessment was completed using MUSICX in accordance with the Water by Design MUSIC
Modelling Guidelines. The proposed bio-retention basin (filter area 45 m², filter media depth 0.4 m) forms the
primary treatment measure for runoff from impervious surfaces.

Section 4.3 summarises the pre-treatment pollutant loads and post-treatment residual loads, demonstrating
compliance with the Urban Stormwater Quality Planning Guidelines (2010). The results summarized in Table 4-1
confirm that stormwater discharges from the site will not degrade receiving waterways and that the system
satisfies best-practice stormwater quality objectives.

Erosion and Sediment Control

During the construction phase, ESC measures must be implemented in accordance with the applicable
requirements.




 12 GYMPIE STREET, TEWANTIN
 Stormwater Management Plan                                                                                      3
 Client Reference: P0198-25-001         4 November 2025
 Prepared for Novato Group