Category: Lagarosiphon

Spraying to start from tomorrow

2/21/2022

From tomorrow until the end of April (excluding weekends and public holidays), there will be intermittent spraying in and around Lake Dunstan to control Lagarosiphon in our waterways.
This work is dependent on suitable weed, water, and weather conditions and therefore the timing is subject to change.

Diquat in gel form will be used to treat aquatic weeds and will be applied by both aerial and boats based spraying methods.

There is be a 24-hour stand-down on swimming, fishing, or taking water for irrigation or domestic supply once the spraying is complete.

See Linz announcement

Crux: Cromwellians invited to guide Lake Dunstan's future

2/1/2022

Locals who get out and about on and around Lake Dunstan are being asked to help create a roadmap to guide how the lake is managed and used.
A survey and a series of workshops and working groups are planned to consult with members of the community on what they see as challenges and opportunities for the lake now and in the decades ahead.

Survey and workshops

A.I. and scientific ingenuity: the next step in protecting NZ's lakes and rivers from invasive aquatic weeds

7/21/2021

NIWA researchers have developed a portable detector to help find and identify submerged weeds. This technology will enable agencies to survey far larger areas more efficiently than is currently possible, and potentially lead to much faster responses to new incursions.

Invasive submerged weeds can degrade water quality, exacerbate silt and flooding, reduce the number of native animals and plants and play havoc with irrigation water delivery and hydroelectric power schemes.

NIWA freshwater ecologist Dr Daniel Clements says early detection and prevention is critical for achieving effective freshwater biosecurity outcomes.

"If you can detect high-risk invasive species early, before they are widespread, and implement effective management strategies, you minimise the long-term economic, environmental, social, recreational, and cultural impacts caused by these species."

Weed Harvesting: How effective has it been in Rotorua Te Arawa Lakes?

6/21/2021

Last week we met the managing director of Lakeweed Harvesters & Contractors to access if we could benefit from a weed harvester on Lake Dunstan. There was a lot of positives to investing in this machinery but also some concerns.

We are currently in talks with LINZ, Contact Energy and the council to access the risk of spreading Lagarosiphon downstream of the dam. Lagarosiphon management costs NZ millions every year and we don't want to increase this cost. Lagarosiphon is already between the Clyde and Roxburgh Dam but currently not lower downstream.

The company we met with currently work on the Rotorua Te Arawa Lakes and a 2020 report accesses the effectiveness of weed harvesting to control aquatic weeds. To read the article and summary, click 'Read more'.

Can we put a weed harvester on Lake Dunstan permanently?

6/16/2021

Today LDCT and some local stakeholders met with the owner of Lakeweed Harvesters & Contractors to access the feasibility of putting a weed harvester on Lake Dunstan permanently to combat the issue of Lagarosiphon.

Diquat: What is it and is it safe?

6/11/2021

Diquat is the herbicide used to combat Lagarosiphon in waterways of New Zealand. You have probably seen the helicopters whizzing around the lake and had to avoid going into the water for 24 hours afterwards. But do you want to know more?

Check, Clean and Dry!

5/31/2021

Make Sure you Check, Clean and Dry all gear when using our waterways!

Freshwater pests such as Lagarosiphon major, Didymo and toxic algae can be devastating to native ecosystems and recreation if they find their way into water bodies.

Lagarosiphon: Skyrocketing to the surface!

5/28/2021

Did you know:

A 10cm piece of Lagarosiphon can regrow to 2 metres in a little as 50-100 days!!

Around 500ha of the lake bed (1/5th of total lake) is suitable for Lagarosiphon and of that 139ha is currently used for recreational use. Lagarosiphon poses many threats to recreation activities, swimmers and biodiversity but is very costly and labour-intensive to manage and eradicate.

Video Update: Lake Dunstan Weed Management Committee Meeting May 2021

5/21/2021

Was great to get up to speed with last year's weed management review and be involved in the next year's plan of controlling the weeds.

To read the initial Lake Dunstan Weed Management Plan 2016-2025, click below

Crux: The town that was sold a lake

6/8/2020

Karleigh Hoera, a trustee of LDCT, says those with the power to do something have largely washed their hands of the affair.
“They’ve just sort of said, look, you know, that’s what’s going to happen and there’s really nothing we can do about it.
“It’s not going to go away.”

To read the article, click below