Extension of Effluent Storage Dam Rip Rap at Nebo WWTP

Dear Sir/Madam An invitation is extended to you to submit a written tender for IRC-W&W-0626-T481 Extension of Effluent Storage Dam Rip Rap at Nebo WWTP. Scope: The Works comprise the supply and installation of a rip rap extension to the existing embankment protection at the Nebo WWTP ESD. The extension shall continue from the existing rip rap toe and extend a minimum of 1.50 metre (measured along the slope) below the current toe level, along the full length of the existing rip rap protection area All works shall be carried out in accordance with the requirements of the Capricorn Municipal Development Guidelines (CMDG), relevant Australian Standards, and the Principal’s specifications. The Contractor shall provide all labour, materials, plant, and supervision necessary to complete the works. Rip Rap Rock • Rip rap shall consist of durable, angular, hard rock complying with CMDG requirements for erosion protection. • Rock shall be free from defects, cracks, weathering, and friable material. • Grading shall be consistent with existing rip rap or as directed by the Superintendent (typically 150–300 mm nominal size unless specified otherwise). • Minimum specific gravity: 2.5 • Maximum Los Angeles abrasion value: 35% Geotextile Filter • Geotextile shall be non-woven, needle-punched filter fabric complying with CMDG filter layer requirements. • Minimum Class A geotextile (or equivalent) suitable for separation and filtration. • Geotextile shall be resistant to UV degradation, biological attack, and chemical exposure. Site Preparation • The ESD shall remain operational during the executions of the works. • Set out the works to match the existing embankment geometry. • The water level of the ESD will be lowered to approximately 1200mm below the existing Rip Rap toe or to an agreed upon level, for the period of the work being executed. • Excavate to a depth of 1.50 metre below the existing rip rap toe or as required to achieve a stable foundation. • Remove all unsuitable materials and dispose of offsite in accordance with environmental regulations. • Ensure excavation does not compromise embankment stability. Foundation Preparation • Trim and compact the subgrade to provide a firm, even surface. • Replace unsuitable foundation material with compacted fill as directed. • Foundation shall conform to the existing batter slope. Geotextile Installation • Place geotextile directly on the prepared subgrade. • Overlaps shall be minimum 300 mm (or greater if specified by manufacturer). • Geotextile shall be placed without wrinkles or folds and secured to prevent movement during rock placement. Rip Rap Placement • Place rip rap to a minimum thickness of 300 mm or to match the existing rip rap layer. • Rock shall be placed (not dumped) to prevent damage to the geotextile. • Ensure proper interlocking of rock to minimise voids and provide a stable surface. • Finished surface shall be uniform and consistent with adjacent existing rip rap. Tie-In to Existing Works • New rip rap shall be keyed into the existing rip rap to form a continuous erosion protection layer. • Any disturbed existing rip rap shall be reinstated to match original condition. Erosion and Sediment Control • Provide and maintain erosion and sediment control measures in accordance with best practice and regulatory requirements. • Prevent sediment migration into surrounding areas and infrastructure during construction. Tolerances and Quality • Finished levels and alignment shall match the existing embankment profile. • Rip rap thickness shall not vary by more than ±50 mm from specified thickness. • Materials and workmanship shall comply with CMDG requirements and be subject to Superintendent approval. Tenders must be in accordance with the attached Specification and Criteria. Please ensure your written tender is lodged prior to the Closing Time, being 2pm Friday, 31 July 2026 AEST. An optional site meeting will be held on Wednesday 15 July 2026 with RSVP required by 13 July 2026. Please see Tender Specification and Conditions of Tender documents for further information. All specification, general enquiries and written tenders must be submitted only. Please do not send tender directly to Project Managers, Project team members or other Council staff. All phone enquiry details will be forwarded to the Contracts & Procurement team as a matter of record. Thank you in anticipation of receipt of your written tender. You will be advised if you have been selected as a successful Respondent in due course. Kind regards Isaac Regional Council