• Welcome
  • Projects
    • Bridge to Bridge >
      • Project Updates
      • Plants >
        • Kids Quiz
    • LINZ 'Jobs for Nature' >
      • Community Vision Report
    • Community Planting
    • Lakeside Clean-up
  • The Issues
    • History of the lake
    • Lagarosiphon
    • Silt/Sediment
    • Water Quality
    • Recreation
    • Pests
    • Biodiversity loss >
      • Protecting our Birds
  • About Us
    • Contact us
    • Volunteer
    • Health and Safety
  • Stay Updated
    • Blog
    • Lake Plans + Resources
LAKE DUNSTAN CHARITABLE TRUST
  • Welcome
  • Projects
    • Bridge to Bridge >
      • Project Updates
      • Plants >
        • Kids Quiz
    • LINZ 'Jobs for Nature' >
      • Community Vision Report
    • Community Planting
    • Lakeside Clean-up
  • The Issues
    • History of the lake
    • Lagarosiphon
    • Silt/Sediment
    • Water Quality
    • Recreation
    • Pests
    • Biodiversity loss >
      • Protecting our Birds
  • About Us
    • Contact us
    • Volunteer
    • Health and Safety
  • Stay Updated
    • Blog
    • Lake Plans + Resources

2023 Annual Lake Dunstan Aquatic Weed Management Meeting

5/9/2023

0 Comments

 
Picture
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.
Overview of methods
  • Hessian not possible in Lake Dunstan
    • For eradiation not sustained control
    • Costs approx. $60,000 per ha plus maintenance costs
  • Hand cutting is no longer popular option for Lake Dunstan
    • Due to high cost
    • But an appropriate backup if spraying is not possible.
    • 1024hr this financial year
  • Harvesters
    • Slow & expensive
    • Need a lot of shoreline space to dry out weeds before transporting.
  • Diquat spraying remains the best option.            
    • Diquat herbicide can achieve control at scale and within a short timeframe.
    • Risk of potential cancellation due to sediment in the water from recent rain
    • More cost-effective when can go ahead.

2022/2023 review
  • Boat-based diquat spraying at all High amenity areas
    • ​Staggered due to unfit weed conditions for spraying
  • Hand-cutting at all High Amenity areas (boat ramps) and High Recreational areas, except Jacksons.
  • Advertisement of works shared to key groups (to share with members/on Facebook), Otago Daily Times and Cromwell Bulletin to inform when works planned.
  • Signage increased significantly around work area to increase public awareness.
    • E.g. 46 signs in place on 9th May when Bendigo Boat Ramp and Approaches, Cromwell Swimming Beach, Lowburn Boat Harbour, McNulty's Inlet, Northburn Ski Lane, and Pisa Moorings sprayed.
  • LINZ, NIWA and Boffa Miskell have seen an increase in public complaints about the use of herbicides and also lack of 'visible' impact on weeds.

Looking ahead
  • In previous years spraying has not occurred at Lowburn harbour/boat ramp due to the Kiwi Water park operating at planned times of works
    • There is now a clause in their permit that will ensure spraying can occur. Correct precautions to prevent people entering the water during 24hr standdown time will be put in place.
  • NIWA investigating another herbicide, Endothall, but no plans to trail in Lake Dunstan in near future
  • NIWA, LINZ and Boffa Miskell to work with stakeholders to increase public awareness of the need for diquat spraying and the safety around its use.
  • Check, Clean, Dry programme by ORC is going through a revamp to update information, resources and public awareness of how to prevent the spread of weeds to other water bodies.
  • Boffa Miskell to liaise with ORC to increase monitoring of sites and ensure events on waterbodies noted and included in works scheduling.
  • Ten Year Management Plan for Lagarosiphon at Lake Dunstan: 2016 to 2025 up for review soon
    • Will connect with stakeholders to update the plan and get community inclusion.
Learn more about Lagarosiphon
0 Comments



Leave a Reply.

    Archives

    September 2023
    July 2023
    June 2023
    May 2023
    April 2023
    March 2023
    February 2023
    January 2023
    December 2022
    November 2022
    October 2022
    September 2022
    August 2022
    July 2022
    May 2022
    April 2022
    March 2022
    February 2022
    January 2022
    December 2021
    November 2021
    October 2021
    September 2021
    August 2021
    July 2021
    June 2021
    May 2021
    April 2021
    March 2021
    February 2021
    December 2020
    November 2020
    September 2020
    August 2020
    July 2020
    June 2020
    March 2020
    December 2019
    November 2019
    August 2019
    February 2019

    RSS Feed

    Categories

    All
    Air Quality
    Biodiversity
    Bridge To Bridge Project
    Kawarau Arm
    Lagarosiphon
    Must Watch
    Native Species
    News Article
    Pests
    Surveys
    Video Update
    Water Quality

Lake Dunstan Charitable Trust Board
​Charity Reg: CC57320
Picture
  • Welcome
  • Projects
    • Bridge to Bridge >
      • Project Updates
      • Plants >
        • Kids Quiz
    • LINZ 'Jobs for Nature' >
      • Community Vision Report
    • Community Planting
    • Lakeside Clean-up
  • The Issues
    • History of the lake
    • Lagarosiphon
    • Silt/Sediment
    • Water Quality
    • Recreation
    • Pests
    • Biodiversity loss >
      • Protecting our Birds
  • About Us
    • Contact us
    • Volunteer
    • Health and Safety
  • Stay Updated
    • Blog
    • Lake Plans + Resources