Marlborough District Council – Caseys Creek PS & Sportsfield Upgrade
Caseys Creek Upgrade – PS & Sportsfield Upgrade
CLIENT: Marlborough District Council.
CONTRACT VALUE: $1.5m
CONTRACT PERIOD: October 2019 – May 2020
This contract comprised the following works:
- Protection of the creek wild-life
- Widening, regrading and placement of erosion protection
- Removal, disposal and replacement of 4 existing creek crossings with DN1800 Culverts
- Provision of temporary access for public to sportsfield during works
- Removal and disposal of redundant structures
- Dewatering of the construction zones and bypass pumping of Caseys Creek for the duration of the works.
- Placement of 650t of rock within the waterway to enhance fish habitat
- Installation of 3000m2 of Turf Reinforcing Matting (TRM)
- Precast design, panel production, installation and construction for new pumpstation and gravity inlet/outlet
- Construction of new DN1800 Gravity outlet and associated concrete cradle and stopbank tie in.
- Construction of new twin DN450 pumped outlet and associated concrete cradle and stopbank tie in.
- Construction of 75m of timber retaining wall
- Re-construction of 250m of Stopbank.
- Landscape planting, hydroseeding and restoration of disturbed areas
Marlborough District Council (MDC) contracted Grant Hood Contracting to undertake the upgrade to Casey’s Creek pumpstation & sportsfield reach. This is the last of 2 separable portions aimed at increasing the stormwater capacity of this spring fed waterway to cope with the expected run-off from a subdivision development currently underway further along Old Renwick Road.
Downstream was the sportsfield reach running through Landsdowne Park. Works here involved fish salvage prior to works, dewatering and bypass pumping and major earthworks to the creek. The creek floor was dredged and regraded, both banks were reshaped and turf reinforcing matting, hydroseed & rock armouring were installed. Two DN1800 culverts were installed in this area to upgrade the existing older culverts.
Grant Hood Contracting offered an alternative methodology to the client for the construction of the new pumpstation. The engineers design was adapted to allow for the precasting of panel components on site. This sped up the construction period in-channel from an estimated 3 months to only 3 weeks. This significantly reduced dewatering and bypass pumping costs as well as eliminating transport requirements for panels to site. Before removal of the original stopbank and pumpstation there was a significant amount of temporary flood protection to put in place, including 170m of temporary stopbank, DN1200 culvert & floodgate & contingency pumping equipment available for coping with any flood events.
Once all temporary flood protection was in place, the existing stopbank was removed, old pumpstation demolished and new pumpstation, DN1800 gravity outfall and twin DN450 pumped lines installed. Then the stopbank was reconstructed, shaped and hydroseeded. Two DN1800 culverts were also installed in this reach along with 75m of timber retaining wall and a further 250m of stopbank upgrade