Category: Lagarosiphon

2023 Annual Lake Dunstan Aquatic Weed Management Meeting

5/9/2023

On 9th May 2023, we attended the annual Lake Dunstan Aquatic Weed Management meeting to review the 2022/23 works and assist in the planning for 2023/24. Toitū Te Whenua LINZ, Boffa Miskell, NIWA, ORC, Otago Fish & Game, Clutha Fisheries Trust, and ourselves were in attendance.

Background

Since 1988, Lagarosipon (or lakeweed) has been 'unmanageable in the Clutha'
By 1996, Lake Dunstan was 'saturated'
Lake Dunstan management is 'sustained control' as it is not possible to effectively eradicate due to reinvasion from upstream (Clutha/Wanaka & Kawarau/Queenstown)
Efforts in Wanaka are focusing on eradication techniques
Queenstown is on prevention and monitoring as currently little is found in Whakatipu
Lake Dunstan - 12 High Amenity areas (boat ramps) and 14 High Recreational areas where monitoring and works occurs.

NOTICE ON UPCOMING LOCAL AQUATIC WEED SPRAYING

4/27/2023

To learn more about Diquat, click the link below

CRUX: Contact Energy commits to Cromwell lake clean up

3/1/2023

Lake Dunstan's volunteer watchdogs are welcoming a new plan that will ensure the owners of the Clyde Dam work to better clean up a section of the lake.

ORC: Media release: Approval for Contact Energy amenities plan at Kawarau Arm

3/1/2023

Contact Energy has delivered a plan for managing landscape and visual amenity values along the Kawarau Arm of Lake Dunstan - within its consents held around its Clyde Hydro scheme in Central Otago.

Read media release

ORC to review Contact Energy's consent conditions

8/26/2022

Back in July there was a brief one in five year window where ORC could trigger a review of resource consent conditions relating to the effects of the Clyde Dam. The Lake Dunstan Charitable Trust submitted two open letters of recommendation to the ORC to request this process be triggered.

Last week, ORC revealed they will progress with a review of conditions associated with the Landscape Visual Amenity Management Plan (LVAMP). Current consents expire in 2042, however, the 5-year windows allow for reassessments and necessary changes to better comply with the RMA.

CRUX - ORC to examine Contact's Clyde dam obligations

8/24/2022

Exactly what Contact Energy needs to do to manage the effects on Lake Dunstan of its operation of the Clyde Dam will come under the spotlight.

The Otago Regional Council has opted to take a once-in-a-five-year opportunity to review the energy company’s resource consent obligations.

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'.