Is our water quality testing of Lake Hawea proactive enough, and are any measured tolerances of deemed good quality appropriate, given climate change.
If you thought that Lake Hawea hasn’t looked right for about a month now, you are not alone and probably not mistaken: pale blue green in colour rather than the normal pale to dark blue. The water is not clear around the edges.
A panorama of the lake last night shows the colour change quite clearly. Of special significance is the drop off in clarity from the, milky look (unusual) in the immediate foreground, going out a few meters to where obscurity now reigns…
This is how it used to look regrading colour and clarity, for years gone by…
The change appears timed with the end of the really hot weather during mid to late January with resulting increased lake water temperatures.
The poor water clarity can’t be explained by suspended mud (clay and mica mineralogy) as the lake has been low all summer with little in-flow. A sudden increase in water inflow, resulting in minimal lake level rise, in relation to the down-graded cyclone Fehi rain event took place after the change in lake water appearance. Furthermore, the lake water quality remained high all last 2016-2017 summer when high lake levels were sustained by north-westerly rain in tributary catchments.
Working on the suspicion that an algal bloom is the cause of the lake colour change, water samples were analysed under a microscope. As a possible cause to the change in lake water quality, a range of micro-organisms were identified including algae, dynoflaggellates and possible cyanobacteria. Whilst the preliminary study is only semi-quantitative, alarmingly the most abundant identified micro-organism is the possible cyanobacteria, the “blooming” of which is mostly likely to cause the current lake water discolouration.
The questions are:
Is the change in water quality only temporary and that it will revert to normal conditions once water temperature stratification is lost resulting in termination of the algal bloom (assuming it is the cause)?
If the lake water clarity does return to normal, will the deterioration be repeated with increased hot weather spells in future summers?
Are our current tolerances of nitrogen levels within the lake too high given the probable increase in mean summer water temperatures resulting in risk to further and perhaps more serious algal blooms.
Anthony Coote MSc (1st Class Hons) MBA, member AIG & SEG
First we need to talk about the lupin’s favoured environment being mainily the braided rivers which drain the Southern Alps – rivers that find it impossible to run in a straight line, and be anything other than dynamic.
When in flood braided rivers carry sediment from the ever rising mountains [geologically speaking] and landslides that frequent such a young country, and at every point where the water flow slows down the carried sediment settles onto the bed of the river, thus in time raising the level of same, and the river, seeking always the path of least resistance, flows off to the side. Thus during high water levels and floods the nature of this predominately gravel environment can change in several hours
The Hunter River that flows into Lake Hawea…
The delightful, endemic and endangered NZ banded dotterel / tuturiwhatu is one of many birds that has evolved to breed in these river beds. Despite exhibiting a variety of seasonal movement patterns ranging from sedentary behaviour, through migration within New Zealand, to trans-Tasman migration, it is hard to not love their comical stop-start actions…
This is typical tuturiwhatu breeding ground – also shared with wrybill and other like minded birds. OK to us humans it is pretty desolate, but keep in mind it lets them see any predators, and when they do they mimic an injury to lure rats, cats and stoats away from off-spring…
Well meaning flower lovers of decades ago decided to brighten up the desolation, and spread the non native lupin seed. They probably never realised the above, and that each seed being coated with a type of oil to preserve it, can survive for several years sprouting only when ideal conditions exist. The perfect seed for such a dynamic bed – they of course then become impossible to get rid of, apart from annual spraying and that is not a cunning or cheap thing to do in waterways annually…
And then there are wilding pines – these ones have been sprayed. The terrain hosting cushion type vegetation is again the sort chosen for nesting…
No one denies the lupins look beautiful. And by-the-way after the brief flowering is over they become anything but ethereal, and more of an eyesore…
Another beautiful frequenter of the braided river environment is the black fronted tern tarapirohe. They spend hours swooping for bugs above and on the glacial silt laden blue/grey water surface, and of course breed nearby…
The natural state as another dawn breaks on a braided river in The Southern Alps…
If only lupins could be confined to roadsides! But even in such a place they invite suicide by flowery eyed tourists, toting cameras that are scant protection against the 110km/hr traffic that rushes by their nearby vehicles, the parking of which is more spontaneous than well thought out…
The two villains together on the shores of Lake Pukaki…
The uniquely billed wrybill / ngutuparore which breeds only in braided rivers of the South Island. It is the only bird in the world with a laterally-curved bill [curved to the right], which it uses to reach insect larvae under rounded riverbed stones. Wrybills are completely dependent on the greywacke shingle of the riverbeds…
Last winter I attended the inaugural, for NZ, Sustainable Summits Conference, at Mt Cook Aoraki Village and did several posts on same. It was one of the most interesting multi-day events I’ve ever attended. For it’s duration my friend Carla Braun-Elwert filmmaker editor artist, made videos, and she has now published them as below.
Click the playlist icon below to see the 36 presentations
Ed Hillary [statue] checks out the conditions on Mt Cook in the distance
Mt Cook Aoraki in it’s winter splendour, as seen from the approach road to the National Park
Mt Cook again from the more unusual viewpoint on the north side of the Tasman River Valley and Lake Pukaki
A personal view by by Laurel Teirney, a former manager at Ministry of Fisheries
The success of the community based/scientist/agency approach we adopted for looking after the whole of the Fiordland, and then the Kaikoura Marine Areas makes me feel we’ve struck on a “magic” formula that just might apply to our lakes and rivers as well.
My passion, at the moment, is finding out if such an approach might work for lovely Lake Wanaka – because I have watched in dismay as numerous lakes and rivers have deteriorated in front of my eyes. So something about our current approach isn’t working for our waterways.
Lake Wanaka photo Laurel Teirney
There are those who say a combined community/scientist/agency approach will not work for this lake catchment – but why not give it a go? After all, what have we got to lose? And surely our lake deserves every effort to keep it in the low nutrient, high water quality category into the future for all our sakes!
Buff weka family feeding in Lake Wanaka shallows in 2008. This species which had become extinct were once common on the eastern South Island. They were reintroduced from the Chatham Islands onto Lake Wanaka’s Stevenson Island and nurtured in an aviary before releases on Te Pekekara and Waikatipu islands and to Mou Waho Island in Lake Wanaka, where they currently enjoy surprising picnicking visitors.
Obviously a healthy lake is paramount not only for the well-being of these very special birds, but other species as well, notably ourselves!
To me the fundamental principles of the approach to managing the Fiordland Marine Area are likely to be the same for lakes – indeed for any type of waterbody.
1] First, the approach is all inclusive – that is, tangata whenua and every “interest” is represented and everyone selects their own representatives.
Fishing boat in Preservation Inlet, Fiordland, with a cargo of cray “pots” [actually cages – lowered near rocks and pulled up again after a few days]. This is financially a high stress job, and dangerous. Also it’s a very different use of the environment compared to recreational fishing, and tourism
2] Then, when the representatives are around the table the first task is to agree on a shared vision. At our first Fiordland meeting in December 1995 there was a palpable sense of unease around the table. But when we went around the table and each person said how they wanted to see the Fiordland Marine Area in 20 years’ time, the unease was replaced by outright surprise – because everyone wanted the same thing!
A recreational diver in Preservation Inlet, Fiordland NZ. 2015. Diving for photos only due to it being a Marine Reserve, and as mentioned below not much is known about this area e.g. the fresh water layer here, on top of the salt water was approx. 5 meters, and nobody seemed to be aware of this – elsewhere it’s typically 1-2 meters
3] From then on, the primary focus stayed with the Fiordland Marine Area, not the desires of any participating group.
Dusky Sound, Fiordland
4] Given the isolation of Fiordland little had been documented about the marine area – so the priority was to gather together what was known. Following the shared vision at the first meeting a large map of Fiordland was laid on the floor. Each group was given different coloured dots and asked to place them on the map according to the locations they valued. Red rock lobster and purple paua dots appeared rapidly all along the coastline. But the blue recreational dots were slower in coming – as we all know rec fishers are a bit reluctant to share info about where they fish…..but when they considered what might happen if they didn’t show their dots they too were around the map and the shared observations and experiences filled the room. Only then did Stewart Bull of the Oraka/Aparima runanga, calmly walk up to the map and place a single yellow Ngai Tahu dot way out in the ocean. Silence fell and then some-one asked “Hey Stu what were you doing way out there?” And he calmly replied, “Oh just looking around”. And that set the tone for the rest of the process – lots of good humour and camaraderie.
Good humour is often evident in Fiordland, especially on the rare sunny day! A pessimist in Dusky Sound, Fiordland does therefore standout – near where Capt. Cook anchored up in Pickersgill Harbour for a month, after a circumnavigation up to three quarters of Antarctica.
One other experience of community knowledge that has stayed with me was the identification of the lines defining the inner fiords from the outer coast. I’ll never forget Pete Young, a blue cod and rock lobster fisher, standing at the maps marking exactly where those lines should be with input and encouragement from the rest of us. It wasn’t until several years later that Steve Wing, our marine scientist, produced data that simply reinforced the lines Pete had drawn.
No place to be in a 4 meter alloy tender with serious white water wanting to drive the bow under, and we’re upstream of a large rock, with all but 5 mm of it submerged – the head of Long Sound in Preservation Inlet, Fiordland
5] And so to the roles of the community and agencies involved. These were complementary right from the start and best described by an “egg analogy”. The yolk represents the community – all passion, commitment and knowledge about their place. The white represents the agencies – all support, advice and management tools for putting the management decisions in place. And there has been an additional benefit as the agencies now work in teams for every issue they deal with.
To me, this approach harnesses all the knowledge, all the passion and all the energy that leads to innovative solutions for even the most difficult issues.
And ongoing motivation is assured by the delight and reward of being involved in looking after one’s own place.
So my “dream” is to see many more of our waterways, be they lakes, rivers or marine areas looked after in such a way. Top of FormAnd logically, extending this from the mountains to the sea (ki uta ki tai), whole catchments could be managed in such a way – though the logistics are rather mind blowing I have to admit!
In the meantime though, I’m just going to continue advocating for a Lake Wanaka Community Management Plan.
The depth of water under the boat at Mou Waho Island on Lake Wanaka is deep enough to engender a sense of vertigo, it’s so clear. So “clear” that maybe we take it for granted!
Sunset – Dusky Sound, Fiordland, New Zealand
Unless stated otherwise all photo credits are Southern Light
More properly named the Te Waikoropupū Springs, they’re the largest freshwater springs in New Zealand, and the largest cold water springs in the Southern Hemisphere and contain some of the clearest water ever measured this side of Antarctica’s near-frozen Weddell Sea, with a visibility of 63 metres.
Antarctica aside the water clarity is in fact not equalled anywhere in the world, and is the result of natural filtering prior to the water’s emergence at Te Waikoropupu Springs.
What we’ve taken for granted for many years is now under threat, and what it’s all about is allocation of water upstream for agricultural use.
It’s not rocket science to ponder that the issue really comes back to what runs into the source areas e.g. nitrates from farming operations.
Read more about it via the link below to a post published by Radio NZ today:
Race to protect Te Waikoropupū Springs
The guardians of Te Waikoropupū Springs in Golden Bay are urging the Environment Minister to preserve and protect it from commercial ventures.