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Interest in co-funding an ecological assessment for dredging?

Hi all
This is as boring as batshit, but is important for dredgers - so please do read to the end.

There seems to be a ever greater concern about dredging and in particular regarding sedimentation, and the impacts of dredging on the aquatic habitat. The Government recently bought in a National Policy Statement which sets out a hierarchy for Councils to apply for assessing consent applications. This is called Te Mana o te Wai or ‘the health of the water’. The hierarchy is:
1st priority- the health and well-being of water
2nd priority - the health needs of people
3rd priority - the ability of people and communities to provide for their social, economic and cultural well-being.

Gold dredging, and your own personal financial improvement, good times drinking chartreuse by the river, mental wellbeing enjoying nature with your mates and family etc comes last.

What this means is Councils and affected parties (DoC, fish and game, Iwi etc) dont actually know how to apply the hierarchy as in, can you have any effects on the river or aquatic organisms from dredging or not? Or, what is the tipping point on effects to the ecology before a consent is declined? This is being raised in consent applications, and for some applicants of dredging consents the affected parties are not providing their approval citing concern about the ecology and conflict with the hierarchy.

To address this, we need a plan. I suggest we all chip in a fixed amount of cash and commission a report from a suitably qualified expert to prepare a report assessing the effects on dredging on sediment and our NZ critters. That can then be provided with any new consent applications and will address these concerns providing some comfort to Councils and affected parties (given we all know how minor dredging actually is on ecology). It could well be a $5-6k project and I do know some people who would be keen to do this work and have the expertise. The issue is cash. I would be interested to hear from those who would chip in. If we had 10-12 people keen to chip in $500 it is achievable. The other issue is for those that don’t chip in, they will still get the benefits of the knowledge and investment from those who do fund the project. I am keen to hear peoples thoughts and interest in doing this work. I am happy to oversee the project (I don’t have a dredging claim) but would need some good support from those claim holders.

If we can get some decent momentum on this, I will be happy to make it happen. If not, well it is a lost opportunity. Your thoughts?


I agree totally about having a plan to present to councils as from my own experience the council is looking for answers to eg: DOC or F & B concerns so its up to us to prove their concerns as inaccurate. I’m more than happy to make a donation. I hope all owners of claims support this

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Hi mangrove, Im in support of your idea. Presumably a report would hopefully find that the environmental effect of dredging is within allowable parameters? I think the person undertaking the study should be well removed from dredging so as to not reduce the credibility of their study. If you get this project going ill donate

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Mathias, that’s a good point and yes, any freshwater ecologist doing this work would be someone with a credible history of scientific reporting in peer reviewed journals fully independent of mining.

We would also need to find a couple of willing claim owners to allow assessments pre and post mining.

Another option might be to contact Otago Uni and see if they have any research/PHD’s that have done work on the topic or might be interested in it?

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Great Idea Darryl , I’d highly recommend Ross Dungey as the fresh water ecologist he doesn’t beat about the bush and has provided me with a favourable outcome in the past , also offered to assist in another project & in general a good bloke , I guess one question that springs to mind is how would the project be able to represent a wide range of rivers , are we mostly talking about how long it takes for biota to recolonise ? .

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I know someone who had done a biota count before and after dredging. It turned out that after dredging, the biota counts are way higher then expected. So the government body which demanded it didn’t want to give the results to the public. There was an “error” in the science and that is the way it was left. Permit approved. No public info available. I might be able to get that report.

Anyways. I may be interested in letting my claim be used for the study. As there us no farming or human disturbances along the length of my claim it would be a good example to go off. Then the Gov can see the difference between a pristine river and farm wastewater rivers. Dredging will for sure be allowed for eternity after that study.

As the dredging community has not been overly helpful to me, I am still up in the air as to helping pay for this study. My claim is good for another 10 years, and watching people try to make a group claim has proven to me that there is a few good dredgers. And a lot of dreamers hoping to suck the gold from our rivers for no effort. I don’t need or want a new claim. But to be able to help the few honest people get their own claims. I may be talked into providing some financial support. Only on the grounds that there is enough people the costs are less then $500 each. As I said. I am not paying for dreamers and leeches. There is a lot of dredging claims. If there is only 10 people or less willing to support this idea. Then for me, it is a wasted cause.


Have a few options for claims on which to conduct the study

There’s a huge number of active claims out there. Cant be to hard to get even 30 guys to chip in say $200. $500 is a bit steep on top of a multitude of other costs. I’d be in for a couple of hundred & my claim to study. Sound reasonable??


There are quite a few studies already looking at the affects of sediment on aquatic ecosystems.
The best first step would probably be to compile existing work before any new research is contemplated.

Unfortunately engaging a “suitably qualified” person to undertake such a project wouldn’t be cheap

I don’t own a claim but am very interested in getting to know someone in southland or finding something myself sometime . I might be able to help but 500 might be a bit much for now. If I can help let me know how.


Hi Mangrove, great idea. I would be happy to fund 50%+ of the costs but we would need to insure the credibility of the assessment is robust.

I have been researching and compiling literature on this topic for the past 12 months. The majority of the available studies have been funded by anti-dredging groups and as such, the results support their mandate.

Fortunately, we do have some local studies (Pomahaka River, 2001 - see attached) that show the effects of suction dredging on the stream invertebrates to be negligible.

Another local study is Bargie, 1998, and I have been trying to source a copy of this from Fish and Game, however they cannot seem to locate a digital or paper copy…


Another source of information would be the ORC. I would assume they conducted studies into the effects of suction dredging prior to making it a permitted activity?
Thompson, R. 2001. Impacts of gold dredging on benthic macroinvertebrates_Pomahaka.pdf (1012.2 KB)


Hi all
Thanks Sam, generous offer.
I meet with, and communicate frequently with freshwater ecologists and have a couple that are highly credible and pragmatic ones in mind. Ross Dungey is a good bloke, but I more inclined to use people who have produced more papers in journals that are peer reviewed who have a national reputation. There are a lot of consultants who would be fine but we need to avoid the ability for the greenies to find an angle to undermine their conclusions. There was a comment about using the University. In my view, that wont suit the brief. I also note the report you attach relates to the invertebrates, and we would also need to be conscious of assessing effects on bullies, galaxiids, lamprey and crustaceans.

I would also suggest using two or three different claims, i.e lowland and upland with differing communities and bed composition/ profile to gather conclusions that all contributors can be confident the findings are relevant to their site.

Sam, if you are happy to fund half this work, then maybe you and I work on this together, or you take the reins and steer the idea from here?


No worries,
Happy to work together so we can utilize our various contacts etc.

Do you have any contacts at Fish and Game or the ORC that would be able to assist in locating the existing literature?

If we can pull together all of the existing and free information on the Pomahaka studies it would be a great start.

I understand the previous owners of the Pomahaka claim 41477 had to provide annual studies to Crown minerals as part of there lease agreement. These reports were done by the Otago Uni and should be readily available. I had several discussions with irritate fisherman over sedimentation and pointed out to them that if they got off there sofa’s when the Pomahaka was in flood they would soon see my poultry efforts were of no consequence in that regard and there was no evidence of my dredging post flood.


Hi all, new to the forum but not new to dealing with regional councils and govt depts. I do not have a dredging claim but am happy to support a collaborative group of like minded ‘goldies’ with a few hundred dollars who are ultimately trying to improve our shared interest.


Hi Darryl I’m willing to make a contribution to funding a report/assessment up to $3,000 needs to be done with the most credible experts you can find with the right letters after their names. I’m pretty confident it will come out with the conclusion suction dredging has minimal effects on stream bed habitats. As long as the report does come out with a positive result then it would help with regional council resource consenting and getting access agreements with DOC. But I think that soon it will become necessary to get an assessment done for every river you want to suction dredge and maybe more than one because the bureaucrats will say conditions are different in each river and between the upper and lower catchment of the same river. There has been and seems like there always will be an ever increasing amount of red tape to cut through before you can legally put a your dredge in the river.


Great to see some serious interest from folks on this matter

Wasting your time, beuracrats need to keep their snouts in the trough so once you clear 1 hurdle theyll have another hoop and hurdle for you to jump through.

Theres no way to be proactive, if you try get ahead of the game theyll just can it altogether.

As mongolminer suggests theyll likely say every river will need its own assesment even upper vs lower and theyll likely take your data twist it and use it against ya. I wouldnt give them ammo to use against you by going ahead with this idea, look at california dredging and thats where nz will be within the decade.

Just get a remote claim and keep your head down, those with easy access claim in the public eye will be the ones to feel the pinch first unless you have deep pockets.

Gogold I have been saying for awhile that we will not be able to legally dredge within 10 years so I agree with you on that. But if we don’t do this assessment it may only be five years. You have to be a long way back now to be able to hide and it’s just not that much fun looking over you shoulder all the time to see who is watching especially when you have just got onto some good ground. All this climate change shit and save the rivers and everything else is covered by this quote don’t know who said it first but it’s so accurate. “The urge to save humanity is almost always a false front for those who wish to rule it” I want freedom but slowly it is being taken away from me on all fronts and it is making me very unhappy