Lake Gilmour Waihi Weed Issue Update
(Note emails modified removing private details and non relevant content, Pat H is our Waihi Sailing Group Hauraki council interface)
ps Emails order newest to oldest as you read down
Attached is some info on the ongoing weed issue and communication with Hauraki Council.
Hopefully Council will visit the lake on a sailing day....
Regards Pat H
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Sent: Monday, November 23, 2020 at 6:07 PM
From: "Pat H" to Council
We sail on Sundays and Wednesdays. Sundays kick off around 11am and Wednesday about midday. As I have mentioned before sailors travel from Thames, Te Puru, Tairua, Morrinsville, Katikait, Waihi Bch, Whangamata and so on. Its a great venue which we dearly love hence the concerns re the weed...
The regatta has been registered at the Waihi Service Centre and we expect that to commence around 10am.
Normally on Sunday there is a mixture of boats - cruising and racing yachts, speed boats, ship replicas, paddle steam boats and so on. Wednesday is now associated with J class RC yachts. The J fleet has grown from around 3 to 12 and most of these have been home built.
it would be great to see you down at the lake
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Sent: Monday, November 23, 2020 at 12:09 PM
From: Hauraki council
Hi Pat,
Please pass on email to Tauranga Radio Sailing Club. I will let you know when we are out there next.
If you send through your regatta/training days we can swing by to.
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From: Pat H
Hi Council, thanks for the response. Good to see monitoring is taking place which will hopefully enable early action on any weed issue.
I will check in with the Waihi Service Centre in regards to the booking arrangements.
Would you mind if I sent your email onto the Tauranga Radio Sailing Club?
Council if your ever at the lake when we sail please give me a ring and I will arrange a sail for you. It is a lot of fun and it would be great to meet you.
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Sent: Friday, November 20, 2020 at 1:44 PM
From: Council
Hi Pat,
Thank you for your email and letting us know that you have a regatta in Late December hosting the North Island NZ 'J' class championships.
Do you know if the use of the lake/reserve for the regatta has been booked with council?.
As being a public reserve others may want to use it as well so it’s best to get your dates in as soon as possible.
As below council has approved the following options for the lake.
THAT Council endorses the implementation of the three options recommended to address the Gilmour Lake aquatic weed issue in support of the radio–controlled sailboat race course at Gilmour Lake, Waihi, as follows:
Option 2 - hand weeding
Option 4 - water level manipulation
Option 9 - aquatic herbicide application, and
THAT the measures recommended in addressing the lake aquatic weed issue in Gilmour Lake are reviewed in 12 months’ time and that the results be reported back to Council.
C20/175 Spicer/Anderson CARRIED
The Parks and Reserves Manager and I were at the lake last week and at this stage the lake weed that causes an issue for the sailing hasn’t started to grow this season.
We have an established relationship with an aquatic specialist who will be coming to look at the lake in the next few weeks for an inspection so we will keep an eye out for the weed you mentioned below.
He is the specialist who gave us the information for the above recommendations.
His work entails most of the country but focuses on the Waikato (Rotorua Lakes, Taupo region lakes and greater Waikato lakes) so is very experienced in this work.
We will keep you informed of work that is going to be done on the aquatic weed.
Cheers Hauraki Council
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Hi Council,
Thought it important to draw your attention to the growth of oxygen weed in Gilmour Lake. This weed I haven't seen before in the lake but is of a variety typically found in gold fish bowls. If this were to become established in the lake then removal would be necessary and costly
Has council inspections also found this weed?.
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Sent: Thursday, May 07, 2020 at 10:57 AM
From: hauraki council
Subject: Tauranga Radio Sailing Club
Hi Pat and David H,
Hope you are both keeping safe and well during this Covid 19 event.
Could you please pass on the following to your members.
Last week a report was presented to Hauraki District Council about Gilmour Lake aquatic weed issues.
There has been considerable research undertaken with NIWA and aquatic weed specialists around the country to gather a range of options available to us.
The options range from $5,000 - $1.3 million dollars.
This is from the report:
The lake is an ecological system that provides council with a retention device, a wetland to clean water and a sanctuary for wildlife and native fish.
It provides an area for the local residents and visitors to recreate and enjoy a lake setting.
Another user group is radio-controlled boat enthusiasts(12). Sunday mornings for the model boat enthusiasts are devoted to sailing practice, and racing.
, , , , , ,
The following options were recommendation as per advice from the aquatic weed specialists.
2. Hand Weeding
· Employment of local contractor
· Useful for controlling small (< 1 m2), localised, sporadic and patchy infestations
· Labour intensive; Not an option for larger infestations
4. Water level manipulation - Lake draw-down is widely practiced in lakes with controlled outlets.
· Minimal disruption to existing ecosystem
· Can be partnered with Hand Weeding.
· Re-growth can be rapid when lake refills;
· chance of adverse impacts (erosion, slumping).
· Limited option with current gate system
9. Aquatic Herbicide application
· Can target a specified area
· The use of Diquat/gel (Hydrogel) for aquatic weed control is now widespread throughout New Zealands’ waterways. Its social acceptance is rapidly improving, as evidenced by most territorial authorities allowing its use as a permitted activity (i.e. no Council discharge permit required).
· Some aquatic weed species have resistance to aquatic herbicide
By approving this recommendation, it will enable an approach that will not damage the integrity of the lakes ecosystem as well as enable the radio-controlled sailboat course to be free of aquatic weed.
The above integrated approach recommendation was resolved(approved).
GILMOUR LAKE AQUATIC WEED (2745402)
The Acting Group Manager – Community Services and Development presented a report which sought approval of measures to address the prolific growth of aquatic weed in Gilmour Lake.
RESOLVED
THAT the report be received.
C20/174 Spicer/Wilkinson CARRIED
The radio-controlled boat enthusiasts use the lake on Sunday mornings for model boat sailing practice, and racing. The aquatic weed inhibits the ability of sailboats to sail due to keels becoming tangled in the weed and have asked that Council give consideration to find a way of reducing the weed growth.
RESOLVED
THAT Council endorses the implementation of the three options recommended to address the Gilmour Lake aquatic weed issue in support of the radio–controlled sailboat race course at Gilmour Lake, Waihi, as follows:
Option 2 - hand weeding
Option 4 - water level manipulation
Option 9 - aquatic herbicide application, and
THAT the measures recommended in addressing the lake aquatic weed issue in Gilmour Lake are reviewed in 12 months’ time and that the results be reported back to Council.
C20/175 Spicer/Anderson CARRIED
Good result for all.
I will be meeting one of the specialists when we go to Covid19 Level 2 to discuss a control program.
From conversations with him so far we will take the following approach:
· Apply aquatic herbicide – works best when weed is standing high beneath the water.
· Assess success of application (will be slower with cooler water temperature) reapply if need be.
· If weed is persistent, manipulate the water level and hand weed the sailing course.
This will be an ongoing program to ensure that your sailing course is able to be used.
Please let me know if you need any further information.
Cheers, Community Services Manager