So far this summer the Horizons’ water quality testing has shown the river (estuary) to be Red on 6 weekly occasions; and Amber on a further 4. That’s 10 weeks out of 16, from 10/12/12 through 26/3/13. The sea has one Red and one Amber. Water testing has its delays, and may be misleading; over Easter, the water in the river was probably the cleanest I have seen it all summer!
I don’t know the location where water is tested, but I suspect Horizons follow the easiest route, with a sample taken from the bridge, and a sample taken from the sea down the end of Manga-Pirau (probably via 4WD down to the sea-edge!).
To answer PC: whilst I am human, and there has been the odd delay between extracting the info from the Horizon’s website, and posting my own-made colour-coded notice on the Notice Board, they have generally gone up each Saturday morning.
I have been actively watching their website since early November; the final week from the 2011-12 summer was displayed right through until the first result for this summer, 10/12/12 was posted. I have kept a written record of posted results.
With one weeks’ exception (see below), Horizons have been consistent with their weekly results (updated by each Saturday). The river (estuary) only had one Green before Christmas and your comment regarding Horizons not updating each week are not correct (excepting one week (7/2), where incomplete results across all testing sites in the region were posted over the weekend, and then revised midweek the following week – including changing Waikawa’s result).
This summer’s results are:
10/12/12 Beach: Green / Estuary: Green.
19/12: G / R
27/12: G / A
3/1/13: G / R
9/1: G / G
16/1: G / R
23/1: G / G
30/1: G / G
7/2**: G / R
13/2: G / R
20/2: A / G (I suspect these are back to front, as they are inconsistent with general pattern)
27/2: G / A
6/3: G / G
13/3: G / A
20/3: R / R
26/3: G / A
All dates are per Horizons’website; results usually published 2-3 days later.
Looking at the above pattern of Reds, these do seem to mirror dumps of rain, which means there is almost certainly a fair whack of farm-wash coming down the river!!
However, water testing results are only part of the equation. I have been holidaying here since 1970. In 1970, the sandbar across the river was bare, and spring tides washed across it. In 1970, most pine trees across the river either did not exist, or were much younger. [Refer the 1978-ish photo in the latest WBRA newsletter.] In 1970, where the river turns and finally heads inland, was a great sand dune (now a forestry block). All these had the effect of providing a great cycle of sand blowing and washing into the river, to be carried back down to the sea.
In 1970, the river below the current bridge (and also upstream past the village), was clean, firm sand. You could watch flounder scuttle across the rippled bottom. I recall the days tractors could safely negotiate across.
Now, the river south of the bridge, is up to 12 inches of soft slushy mud, with sticks and the occasional log). Pick up a handful, and the smell is most distasteful. The sandbar just down from the bridge is now a thinly disguised mudflat.
Most surprisingly, was the number of holiday makers that turned up for the boat-day, when my sign on the noticeboard clearly indicated the water-testing result that week, was red.
Now I am no ecologist. I have no scientific degree. I simply have my lifetime of accumulated experiences and memories. It’s called oral history. To other old hands that I share these with, there is always a voice of unaminity.
On the one hand, I am sure farming has contributed to the state of the river and water quality (just last week, I saw cows standing in the freshly cleared drain behind Sarah St. This drain exits via Manga Pirau stream, through Hank Edward’s reserve);
On the other hand I am convinced that ecological improvements (planting sand dune grasses; pine and conifer trees etc) to ‘stabilize’ the environment have altered the ecology of the river, by removing the great sand-cycle.
Case in point. The river mouth, the stretch that is exposed to the elements past the line of sand dunes to the north, presents the same attributes as what the river used to display further upstream.
And thirdly, I understand water is drawn from the river upstream for various farming purposes, resulting in a reduced average flow.
[Just wait, one day Horizons will spend maybe $50,000 of ratepayers’ taxes for a hotshot post-grad student working on their PhD to undertake a lengthy study to work out the reasons for the decline in the river-quality, something I have just documented over the course of two beers.]
In the meantime … what?
6 thoughts on “River Water Quality – A Personal View by A Veres”
A few points in reply to A Veres (thanks for posting water results on the notice board!):
Horizons has confirmed their estuary testing is at the bridge, and beach testing is aprox. 200m north of the river mouth.
The problems I encountered with no water testing results for a few weeks were to do with my web browser and not with Horizons, but they have now resolved themselves! Yes, Horizons have been reliable with their water testing all summer so that is good.
I felt like a mean Mum not letting my kids do the swim on boat day due to water quality, but couldn’t keep them out of the kayak races – it is hard for them to understand when it is one of their favourite beach events and lots of other people are participating.
We have been holidaying regularly since about 1980 and have also noticed lots of changes to the river over that time. We used to have a clear view of the sea over the river all along the coast but now it is all tall dunes, and I hadn’t thought about the effect this may have had on the river with less sand scouring it out but perhaps you are right. There are probably a number of contributing factors.
I’ll try to get some more info. from Horizons on where it is all at currently in terms to trying to improve the situation, although of course it is going to take a number of years.
PC: if you wish to talk further / collaborate, I am at #10 MangaPirau.
Thanks Frank – you know my husband and kids, they came to see you after sand sculpture day (we were the next door whale!)
I have e-mailed Logan Brown at Horizons (he is an environmental scientist for water quality and told me about testing locations) but have not yet heard anything. Will keep you posted.
Horizons Regional Council Replies
We monitor the water quality in the Waikawa Estuary on a weekly basis during the bathing season (1 November to 30 April inclusive) and the results from this monitoring are placed on the Regional Council’s website each Friday night. The monitoring is done at the footbridge.
We have had a brief look back through the results for this bathing season and from 20 monitoring occasions there were 5 times that we would recommend that people do not swim as a result of high E.coli levels. In general these high E. coli levels were also associated with high river flows (in general, rainfall causing contaminants to wash off the land). The E.coli levels are not due to the formation of the sandbar or as a result of slower moving water but as a result of land use. This is one of the reasons that the Waikawa Stream has been identified in the Proposed One Plan as a priority catchment for the management of diffuse contaminants (the Proposed One Plan however is still going through the Environment Court process).
In terms of the sand bar formation this will not contribute to the water quality in the Waikawa Stream however, the sandbar is important in terms of estuary formation and providing more habitat within the Waikawa Estuary for flounder and for inanga spawning which in turn provides recreational opportunities.
Hopefully this answers any concerns you have regarding the water quality in the Waikawa Estuary – the weekly monitoring will continue till the end of April this year and will then recommence in November with all the information being provided at the above website.
The answer to the question “If the state of the water reaches the point where it is considered that the water is not suitable for swimming do your staff erect signs that would make the general public aware of the situation?”
In short no.
The monitoring undertaken on a weekly basis provides an indication of what the water quality in the estuary is like given the flow conditions. With the monitoring undertaken on a Wednesday and the results coming back on a Friday afternoon (due to having to grow E.coli over 24 hours at the lab) placing signage at the river is likely to provide the public with a false sense of security i.e. that when there are no signs it is fine to swim. The monitoring simply tells us that at that point in time it was either considered safe or not and from this we can gather information on what the water quality is generally like. To put you mind at ease at those sites where we do see consistently high E.coli results we do place permanent signage e.g. Moawhanau Stream at Kai Iwi. The Waikawa Estuary at this stage does not warrant permanent signage.
After collecting five years worth of data we are able to grade a site according to its E. coli results and the land use characteristics in the catchment. For this grading we use a Ministry for the Environment methodology but at this stage we have only collected 2 years worth of data for the Waikawa Estuary. Once the Waikawa Estaury has received its grading it will be placed onto the following website. http://www.horizons.govt.nz/managing-environment/resource-management/water/safe-swim-spots/grading-and-general-rules-of-thumb/
Also on the website we provide the following recommendation for swimming spots as well as updating the weekly results – these two tools then allow people to decide for themselves whether they consider that it is appropriate to swim.
Results shown below are the latest readings from the 2012/13 summer monitoring. These relate to monitoring of indicator bacteria and observations of cyanobacteria (blue-green) mats in stoney bed rivers. The result is for the day the monitoring or observations were done. It is possible water quality has changed since then, especially if it has rained recently.
We recommend you use the following rules of thumb before using any rivers in the Region:
• If the water looks clean and clear and it is a sunny day, it should be safe to swim
• It is safest to wait three days after rain before swimming at river swimming spots
• If musty smelling, black slimy mat-like growths are observed on river bed stones it is safest for you and your dog to avoid using the river.
Horizons Regional Council monitors water quality throughout the summer months both in the stream by the bridge, and also in the sea.
Horizon’s state on their website, that the sea-water quality “very rarely” exceeds guideline values for swimming, which I interpret mas meaning, is ”very rarely” rated as ‘RED’ I note they don’t state this for the stream.
This year, Horizons are publishing slightly extended details about water quality, including bacteria-specific results and also some forecasting for each weekend.
Over the last two summers, I have endeavoured to transfer Horizons website details to colour-coded notices on the noticeboard.
This year, I shall only place colour-coded sheets with minimal details. Ratepayers are urged to visit Horizons website for fuller details.
‘in the sea’: http://www.horizons.govt.nz/managing-environment/resource-management/water/safe-swim-spots/coastal-swim-spots/
‘in the river’: http://www.horizons.govt.nz/managing-environment/resource-management/water/safe-swim-spots/freshwater-swim-spots/
Further to the above, and useful information in the lead up to Christmas, Water Quality over the last 5 weeks in the sea has been consistently ‘Green’ (or ‘safe’).
Water quality in the river has been ‘Green’ (‘safe’) once; ‘Amber’ (‘satisfactory’) twice, and ‘Red’ (‘could be a health risk’) also twice. In each ‘red’ or ‘amber’ result, water testing has failed the e-coli tests.
Horizons’ website state that the estuary is “That means it is almost always safe for swimming when the tide floods into the estuary and is generally safe for swimming on an outgoing tide, except during and after a river fresh”
On a separate note, riverbank quality has deteriorated markedly over the last several years, with mud settling on the river-side just below the bridge; and across the flats just down from the bridge. It is no longer particularly appealing to sit alongside or wade or splash in the river (things do improve closer to the river mouth). If you wade across the river, you wade through up to a foot of ‘sludge’. This is massive contract to a generation ago, when the river had a firm sandy bottom.
“Almost always safe”? One week in the last 5 = ‘green’?
Want to swim in the river?