This Expression of interest is for the construction of three separate Stormwater Improvement Projects within the Mangawhai area.

The Stormwater improvement strategy for Mangawhai, has identified the following key projects to be delivered as part of the 2023/24 Programme;

As part of ongoing Stormwater improvements strategy for Mangawhai, Kaipara District Council have identified three key projects to be delivered as part of the 2023/24 Programme;

Project 1: Robert Street Stormwater Improvements

Located at the southern end of Robert Street, the detailed design has been completed by ACH Consultants with the proposed works involving the following;

1. Construction of catchpits and control chambers and connections.

2. Construction of 110m of 355mm OD PE Pipeline utilizing trenchless drilling technology.

3. Construction of intermediate and outfall chambers, scour protection works and environmental planting.

Project 2: Eveline Street Stormwater Improvements

Located at the eastern segment of Eveline Street (to the east of 12 Eveline Street), the detailed design is currently being finalized by Stantec, with the proposed works involving the following;

1. Construction of kerb and channel, catchpits, control chambers and connections at the end of the eastern segment of Eveline Street.

2. Construction of approximately 140m of open half pipe channel, control structures and scour protection to outfall with earthworks reshaping of existing grassed walkway to assist in stormwater conveyance.

3. Construction of a planted bioretention area at outfall consisting of approximately 150m2 including indigenous planting with control weir to beach level discharge

4. Installation approximately 500m2 of new indigenous vegetation planting within the grassed walkway area.

Project 3: Breve Street Stormwater Improvements

Located in the Breve Street Reserve at the end of Breve Street, the detailed design is currently being prepared by Stantec, with the initial proposed treatment indicating the following improvements;

1. Removal of debris and remediation of existing gabion stormwater control structures

2. Installation of Rip/Rap or Gabion mattress lining to channel and Rip/Rap or Gabion structure protection to lower slopes of gulley.

3. Installation of geosynthetic slop stabilization protection to upper slopes and installation of planting to assist with stabilization and erosion control.

The Mangawhai Stormwater Upgrade Projects will be a two staged process;

1. Expression of Interest (EOI) Open Market

2. Request for Tender (RFT) List of suppliers from EOI

This EOI is the first formal step in this process and is intended to be of minimal effort for respondents and allow KDC to create a list of interested suppliers to invite to enter the RFT process.