Waiology

Dr Daniel Collins is a hydrologist at NIWA. He formed the Waiology blog to bring together commentary on New Zealand's freshwater systems. The blog features commentary from numerous contributors.

Whitebait: more than meets the eye - Waiology

Aug 15, 2013

By Amber McEwan Beginning today, August 15th, a bunch of keen New Zealanders will creep out of their homes in the freezing dark morning and take to the rivers armed with waders, swandris and optimistic hearts. This canny lot set up their pozzies and then wait for luck to strike. To other whitebaiters in the area they give nothing away except sidelong glances. Enquiries about the day’s catch will likely yield a gruff “nah, not much” regardless of how much ‘white gold’ is stashed away in a keepnet or bucket. Whitebait are a kiwi icon, but there is a lot more to these teeny tiny, tasty fish than meets the eye. Unbeknownst to many people, the word “whitebait” actually refers to the young of five species of native freshwater fish. Most of these species are found nowhere else … Read More

A heavy load to carry for native kōura - Waiology

Jul 19, 2013

By Amber McEwan This winter, in a cold, clear stream near you, a certain freshwater crustacean has a heavy load to carry. The female New Zealand freshwater crayfish, or kōura, spends the winter months carrying large eggs (up to 200 of them!) attached to the underside of her abdomen. The eggs hatch after 3 or 4 months, but motherhood doesn’t end there for the female kōura – the tiny babies (miniature replicas of their parents) hang on to their mother and she carries them everywhere she goes until they are around 4 mm long, at which point they let go of mum and head off to seek their aquatic fortunes. Quite a large example of the ‘North Island’ kōura (Photo: Amber McEwan) There are two species of kōura in New Zealand (loosely divided into North and South Island species) … Read More

NIWA’s Citizen Snow Project: How deep is the snow at your place? - Waiology

Jun 20, 2013

By Daniel Collins With the current storm crossing the country this week, NIWA has kicked off its Citizen Snow Project. The project seeks assistance from public at large to contribute to New Zealand’s snow science research by gathering snow measurements at home, in their neighbourhood, or wherever they may be. Snow measurements at NIWA’s Tekapo field office, morning of 20 June, 2013. (Credit: H. McDermott)The new data will go alongside data collected by NIWA and other organisations, and will help build up a better picture of how much snow falls during severe storms, particularly at low elevations. The information would be used to plan emergency responses in the future and to help gauge the risk of traffic disruptions, infrastructure damage and agricultural losses. Members of the public are asked to make measurements of snow depth and snow … Read More

No water no problem for mudfish - Waiology

Jun 10, 2013

By Amber McEwan While we head for the indoors as the weather grows colder and wetter, a secretive, little eel-like fish is gearing up for its busiest time of year.Brown mudfish (Neochanna apoda).(Photo: Alton Perrie)The remarkable brown mudfish is one of five mudfish species that are all unique to New Zealand. They are small (up to around 15 cm), long and skinny and nocturnal. They live in wetland environments that tend to dry out in summer and survive these dry periods in a similar way to how bears survive the winter – they aestivate. To aestivate is to slow down your metabolism, burrow into the mud and hunker down until the rains come again. This way, the brown mudfish is actually able to survive out of the water for several months! When the autumn and winter rains re-flood the … Read More

Rhombosolea retiaria: The freshwater flounder - Waiology

May 30, 2013

By Amber McEwan In lakes, rivers and estuaries throughout New Zealand, groups of aquatic flying carpets are mobilising and moving downstream towards the sea. Late autumn marks the time when a special species of New Zealand flatfish – the freshwater black flounder or patiki – embarks upon a spawning migration to the sea, with juveniles re-entering freshwater and migrating back upstream a few months later. The endemic black flounder, Rhombosolea retiaria (Photo: Alton Perrie).The black flounder (Rhombosolea retiaria) is a truly fascinating native freshwater fish species. They are found mostly in freshwater, in lakes and streams close to the coast, although they have been known to travel as far as 250km inland! They also complete migration-like movements in marine environments, some of which can be astonishingly large – one flounder that was tagged during a research study in … Read More

A tale of two storms - Waiology

May 10, 2013

By Martin Doyle The rainstorm near Nelson on 21 April, 2013, was one of the most intense ever measured in New Zealand, and caused considerable flooding through urban Stoke and Richmond. Just 18 months prior, another storm also caused significant damage to the same area. It would be tempting to draw parallels between the two storms, but in fact they provide an interesting contrast.Comparison of the 2011 and 2013 storms, measured at the Tasman District Council office. Rainfall totals over the period of graph are nearly identical.The figure to the right shows the hourly rainfall from the onset of rain for the two storms. The total rainfall over the 24-hour periods was 192 mm for the 2011 storm and 191 mm for 2013. Despite this similarity, in December 2011 the rainfall was much less intense. The 2011 storm … Read More

How to drought-proof New Zealand as droughts get worse - Waiology

May 03, 2013

By Daniel Collins For the most part, droughts are natural events. Rainfall and river flows wax and wane, and there will be times when there just isn’t enough water to fully meet our needs, whether to grow crops or to quench a city’s thirst. Wairarapa drought, February 2013. (Credit: D. Allen, NIWA)And when it comes down to it, that’s really the best definition of a drought: when water supply is insufficient to meet demand. If no rain falls on the land, and there is no-one there to go thirsty, is it a problem? But there is a growing part of drought that isn’t natural. Increases in water use, beyond the capacity of the environment to supply the water, have led to what are called “demand-driven droughts”. Changing climate has been implicated in changing patterns of drought … Read More

Reader feedback invited for Waiology - Waiology

Apr 09, 2013

By Daniel Collins Waiology has been running for the better part of two years now, and has just completed a significant series on water governance. And as Waiology moves ahead, it would be very helpful to know what you think about the blog. Are you happy with the status quo? What’s good or not so good? How useful and informative is Waiology? What topics would you like covered in the future? How can Waiology engage with you and others better? What holds you back from commenting on articles? Are you a subscriber? How do you hear about Waiology articles? Are you a member of the public or the freshwater community? If freshwater, what do you do and where do you work? Feel free to respond with this online survey, in the comments below, via the contact page, … Read More

Water governance in New Zealand: A conclusion - Waiology

Apr 08, 2013

By Daniel Collins When it comes to managing our freshwaters well, science can provide only part of the solution. It is important to appreciate how much water we have, what quality it is, and how our activities change these things – questions that only science can answer – but it is also important to appreciate what people want from their freshwater, how they value water, and how to broker agreements when people don’t exactly see eye to eye. This is the domain of water governance. And for the past five weeks we have been examining water governance in New Zealand with particular consideration for the role of science. We have heard from 16 different people from 14 different organisations offering a variety of perspectives of how water is, or should be, governed. And because science is an indispensable part, … Read More

Collaborative water management delivers local solutions in north Canterbury - Waiology

Apr 04, 2013

By David Eder and Ian Whitehouse In July 2013 the Hurunui-Waiau Zone Committee will notch up three years of work. It was set up as part of the Canterbury Water Management Strategy – a collaborative process for finding local solutions to water issues within an environmentally sustainable framework. In July 2010 the committee’s daunting task was to sort out water storage in the Hurunui catchment and set water quality limits. We held dozens of committee meetings, public meetings involving more than 300 people, and received written feedback from more than 120 people before finalising our zone implementation programme of recommendations. Working collaboratively empowered us to reach consensus decisions on local water issues that are acceptable to a wide range of people. The ZIP now guides local government work programmes and policy to achieve the agreed … Read More