The Harbour team, HEB Construction, have thanked Ōpōtiki boaties for their support throughout the build process and channel closure at Ōpōtiki’s new Harbour entrance. They now ask for continued patience for several more weeks to ensure the new harbour entrance is safe on opening to the public. They now expect that the channel will be open to boats in mid-September.
Bay of Plenty Harbourmaster, Jon Jon Peters, has extended the closure of the river to 11 September to allow the works to continue.
“I appreciate this closure is taking longer than people hoped, but safety needs to come first, and unfortunately at the moment its simply not safe for boaties to pass through this area,” Mr Peters said.
David Wyeth, HEB construction’s Project Manager said that dredging the channel between the new seawalls was a complex enterprise and there was still a lot of additional sand to excavate before the channel could open safely and permanently.
“On the dredging front there is good news and bad news. The good news is that ocean depths beyond the breakwaters have improved and now appear stable and sand movement is limited out there which is great. However, that sand has deposited between the breakwaters requiring us to dredge this out sufficiently to allow boat access.
“The project had this possibility built into our timeframes, but it does mean a longer period without access to the open ocean for Ōpōtiki boat owners. We really do appreciate this is a long time without a river entrance and this is a much-anticipated piece of infrastructure. But health and safety must come first and the last thing anyone wants are boats coming to grief through the new harbour entrance before it is safe,” David Wyeth said.
The harbour entrance is being dredged to a depth of four metres at mid tide, but with the relatively dry period in the weeks following cut-through and the low river flows, the river hasn’t been flushing as it normally would, and the sand was therefore moving in from further out to sea.
David Wyeth said that his team are mobilising a large barge with additional pumps to help speed up the process – the Pohonui barge is 50m x 14m with a dredge pump mounted on top.
“Within the next week or two, we expect to welcome Pohonui and it will be operating up to seven days a week to help us move the material as quickly as possible. We’ll also have an additional amphibious undercarriage dredge operating alongside Hinewai, which has been on the site for the past year. Essentially, we will have three dredge pumps running in the near future, moving things along as quickly as possible.
“We’ll keep the community updated on dredging progress so it won’t be closed any longer than it has to be. But I’d ask again that people stay clear of the area on land and sea. With the large dredge between the seawalls and the two other barges operating, their pipes and the various structures and hazards, it is absolutely unsafe for boats at the moment. The exception is the Coastguard and if they need to get through, we can assist them and clear space,” David Wyeth said.
Dredged sand will be added to the stockpile of the western side of the harbour and will then be used to close the old river mouth. The old channel is currently sealed with a ‘fuse’ – a thin strip of sand that can act as a flood relief valve in a flood event. Once the new channel is at sufficient depth, the fuse will not be needed and the old river channel area can be fully closed in and the areas restored to dunes and native plantings. The additional material dredged over the coming weeks will be valuable for fill in this large area.
The aerial image below shows the current levels within the channel and illustrates the additional material that has migrated between the breakwaters. On the positive side, this means that dredging does not now need to extend beyond the breakwaters, but it “creates a few headaches” in the short term for access for Ōpōtiki boaties.