The lakebed, dewatered zone, islands and the Hokio Stream are owned by beneficial members of the Muaupoko tribe 1511 of them in 81 shares, as determined by the Reserves and other Lands Disposal Act (ROLD) 1956. The lake waters Muaupoko Domain, dewatered zone and one chain reserve strip in front of the Muaupoko Domain are vested under the Reserves Act 1977 in the Horowhenua Lake Domain Board. To date they have achieved nothing and even today sewerage is released into the Horowhenua Lake by the Council when it is overloaded.

HOROWHENUA LAKE ACCORD CLEANUP 2013

THE ACCORD PROCESS

With the Council now seeking an Accord to clean up the Lake local Iwi have now banded together to form a community team to assist in the clean up with Raukawa. Some members of the Lake Trustees tried to pass the Accord and have it signed as they were in for jobs of course but those that stuck to their guns like Kaumatua Charles Rudd and Vivienne Taueki who are for the people not themselves blocked the necessary signing which would mean the Council would lead this Accord and could then dictate the outcome or the delays. A meeting on the 14th April 2013 will see a new community committee set up to be part of this process.

But first of all to start anything the contamination must be stopped entering the Lake & there are no monitoring equipment on any inlets at all as at May 2013.

[ Check Horowhenua District Councils low rating in the 2013 League Rating for Councils in NZ ]. They are second to last so if you are in Levin on the 7th July at 2pm listen to Larry Mitchell exposing the District Councils blatent spending spree.

Five groups have been invited to take part in the Lake Horowhenua Accord but this needs to be extended as even the majority of the 1511 owners have no say nor allowed to voice their opinions and it is their land. The 5 have a different role in the lake's management yet there has been no indication os the management structure; the monetary fund & the planned clean up.

Lake Horowhenua Trust: The elected representatives of lake's owners 1000+ owners are not even informed or know about this Accord. No owners have seen a Draft plan that came out in 2012. But as at June 2013 the Lake Trustees have a Court case & nothing has been presented. The lake, along with a 20 metre strip around its edge, is owned by the owners, the majority of which are of the Mauapoko iwi.

Horizons Regional Council:

The environmental regulatory grants consents for stormwater and wastewater disposal. Horizons also carries out water quality monitoring and weed spraying at the lake. HOWEVER they are not monitoring the inlets to the Lake the most important task and basically never have??? But in saying this they are happy that more groups join the Lobby Group and are happy to work with us.

Horowhenua District Council: is the local authority responsible for bylaws that govern the lake,and suposedly keep clean yet they have done little in fact nothing to relieve the problems of the Lake. They have no money to spend on stormwater and runoff into the Lake nor have money to spend on the Lake. They should not lead any Accord due to their neglect over 62 years. In all there have been 3 Accords to date and nothing ever happened and the Council are to blame. Blame can not be put on Mayor Duffy as without the likes of Horizons etc, Nathan Guy, DOC these are the ones who must share repsonsibility and they have had many years to support the Council.

Department of Conservation: DOC is responsible for the flora and fauna at the lake but as we have seen thats all thats been done on the Lake. They have re-established native species with Iwi reps on the payroll in and around the lake and the control of pest species.

Lake Horowhenua Domain Board: With representatives of Horowhenua District Council, DOC and the lake trustees, this board manages the lake waters only and the use of the buildings? yet tend to talk about solving issues but has never implemented the clean up process or come up with any plans to rid the sludge in the Lake. They are in fact a dufunct Board that the Crown needs to get rid of as they get paid to meet yet never carry out what even speakers ask for.

In the USA the Environental Agency identified these parties creating separate work groups were created to handle the various aspects ofthe Great Lake issues

• A Toxicity/Chemistry Work Group collected and quantified data on contaminants in sediments and studied the effects these contaminants have on fish and other aquatic life.
• The Risk Assessment/Modeling Group studied risks to humans and wildlife created by existing conditions and compared them to the risks that would result from various possible alternatives avilable for remediating sediment problems.
• The Engineering/Technology Work Group tested and evaluated technologies that might be used to clean up toxics in sediments.
• The Communication/Liaison Work Group collected and disseminated information to citizens about contaminated sediments and provided opportunities for citizens to participate in the work of the program. [ Read more]

Click here to download the Accord Draft Plan [OPEN pdf: ] as at 14th May 2013

PROPOSED PLAN CLEANUP

The problem is the toxic sediment on the bottom of the Lake that must be removed and the following is how this can be achieved according to the budget provided. Over the decades, heavy metals and toxic organic chemicals--both municipal and industrial wastes and herbicides and pesticides from farm runoff--have mixed with the particles of rock, soil, and decomposing items in the Lake. Little attention has been paid to the toxics hiding in the mud on the bottom. The obvious first priority was stopping the discharge of new contaminants.

We have a proposal to show the parties.

1/. Using Amphibious pontoons using 35- 40t excavators. or eg. Hitachi EX800 using a spud-barge was used successfully with a hydraulic dredging unit and Trimble GPS allowing the use of precise naviagtion of extraction & guaging the turbancy of the sediment removal. The use of barges to relay back sediment or direct feed back to the shoreline can be considered. The sediment can then be sift through for separation & taonga [artifacts and Maori relics]? The downside of firect bucket extraction is the spillage of sediment in the loading onto the barge & the hydraulic dredging on the turnbancy of the sediment so in areas of high turbancy the system would slow down or stop to prevent the sediment dispersing-- but its the most practical of the options I can see. This is the various options of dredging as then easier to sift thru for taonga although some overspill will occur in loading.


2/. A closed bucket dredge is another way or clam shell dredge yet another way of sediment removal but if an open bucket again excess sediment can fall off on loading so must be closed bucket. .

3/. Last is a vaccuum hydraulic dredge as mentioned which uses high velocity water but also brings up lots of water is another avenue to look at as worked successfully in the Great Lakes sediment removal.

4/. Empty the Lake/clean it out and start again-- NOT an option as in Maori to have no water is
like emptying our bodies??


GUAGING DEPTH & where to start?

1/. The depth of the whole Horowhenua Lake can be checked using sonar and the use of GPS to coordinate the planned graph marking grids then using a 3D chart of the Lake bed. Sonar uses a combined transmitter and receiver, called a transducer, sends a sound pulse straight down into the water and the resulting pulse bounces off the bottom. The transducer is able to pick up the reflected sound. Computers precisely measure the time it takes for the sound pulse to reach the bottom and return. In shallow water the sound waves will return very fast to receive the echoes. The floor mapping is called echosounding. Echosounders can use different frequencies of sound to find out different things about the bottom. Water depth is typically measured by echosounders that transmit sound at 12 kiloHertz (kHz). Lower frequencies (3.5 kHz) can be used to look at the layers of sediments below the lake floor so now depth can be judged once samples are taken. You need to have a Pilot flat bottom Boat complete with computers and echo sounder software plus the taking and analysing of sediment core samples at various levels below the lake bottom.

VIBRO CORING UNIT: A flat bottom pilot boat needs to have a vibro-coring unit allowing the sample of cores up to 5m below the bottom [ not sure length at this stage]  long from locations with water depth between 1-5m [ the Lake is approx 2-3 m deep?. It is equipped with a differentially corrected global positioning system (a Navstar GPS for accurate positioning or Trimble system ) with submeter accuracy that allows for precise and accurate determinations of sample locations to be then set into a grid of the lake floor. Once samples are collected, they can either be subsampled and processed onboard or at land-based facilities and then coordinated on a 3 dimentional map of the Lake. This will then show with accuracy the sediment concentrations of the whole lake and the depths these sediments are located. It will also show hot spots of sediments that can be removed first in order of priority allowing for the good and bad areas to be shown so the removal phase can start at the worst contaminated areas according to the allowable budget. Sediments could be further anaylsed in their proportionate values from the worst to the least contaminant in order of removal & disposal once collected on shore. Again to succeed all inets into the lake must be stopped of contaminants first and foremost.

BARGE: Need to be able to relocate to the shore for separation and dispersal per each grid and for the collection of taonga [artifacts] . Due to the shallow draft of the Lake this may not be practical so a piping system may replace the barges. There should be a screening process then contaminants separated within the toxic calibrations noted & then stacked in contaminated areas according to its rating and later trucked out once dried out on shore & decleared safe of contaminants ready for disposal. In the USA they have screened sediments to be used back as fertilizer.

WEIR: On no account should the weir be destroyed [ this is a weir erected on the outlet side to the hokio stream to the sea] and lose the level of the Lake as it will compound the problem but instead have a channel of water diverted around the weir which I believe Horizons are working on. The weir allows the height of the lake but of course does not allow sediment to escape causing buildup.

COSTS:

Will the required budget be enough to dredge the whole lake with those responsible eg. Council, Horizons DOC, Govt grants budgeting the cleanup? Would dredging the hot spots first be better then the lake rechecked being within the required budget? Where to start first and end noting the main inlets and outlet being the Hokio Stream.

This whole process could be accomplished using owners and overseen by the necessary authorities. It would also be a workable business for the owners to accomplish the same in other contaminated parts of NEW Zealand as we have a duty to our tipuna. This is another reason why us owners need to play their role in the Accord process and not be left out.

It has been 62 years that Horowhenua Lake has had sediment, sewerage and contaminants from dairy & horticulture in this Lake ? The Lake is choked with weed, sediment and manures from horticulture and dairy farm run offs account for 50% of the water runoff and this Lake is No 107 of a total 114 most contaminated Lakes in NZ by the Ministry of the Environment. Once rich in food sources from mussels to kakahi it has now been reduced to a contaminated mess.

Jon Roygard is also about to start monitoring the Lake from Horizons and this is a good approach. We hope to bring you more news as time goes by as some of Te Keepa will be working with Jon liasing and learning as well for their people

[ ROLD submission ] [ Horowhenua Lake History ]  [ Lake Accord 2 3 4 5 6 7 8 9 10 [ Lake Accord 2015 harvest machine ] [ Sewerage back into the Lake August 2014 ] [ MTA Board & Tuia ] [ MLC Injunction on boat ban Nov 19th 2013 ] [ Council want to repollute the Lake Sept 2013 ] [ Lake Accord Council update to repollute using Queen St Drain ] [ Lobby update June 2013 ] [ Larry Mitchell & the Council ] [ ROLD submission ] [ Horowhenua Lake History ] [ 2023 BLAME ]