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.

Happy holidays from Waiology! - Waiology

Dec 23, 2013

By Daniel Collins After the recent water quality series, Waiology will be taking a break over the holidays, springing back to action mid-January. Over the course of the year, Waiology published 67 articles and hosted four series – on wetlands, water governance, water quality, and native freshwater fauna. See the archives for the complete list. Based on visits to specific articles, the most popular one this year was Bob Wilcock’s on dicyandiamide (DCD), at 4500 pageviews. The second most popular, at 2500 pageviews, was my article from last year on the water footprint of milk. A few other highlights from this year were: Who owns water? Māori or the Crown? – by Jacinta Ruru How to drought-proof New Zealand as droughts get worse – by Daniel Collins What causes didymo blooms … Read More

Un-muddying the waters: Series conclusion - Waiology

Dec 20, 2013

By Daniel Collins After 10 weeks and 26 articles, Waiology’s series on water quality draws to a close. We have heard from 26 different contributors from 10 different organisations. Articles spanned topics from states and trends in observational data to diverse management solutions. There were some glaring omissions, for which I apologise, but not all requests translated into articles for one reason or another. It is hard to provide a summary of the series, and no such summary could canvas the entirety of the science and management or water quality in New Zealand, but I shall offer you some of the more pertinent points. Water quality is generally declining due to land use intensification, and without significant action from a range of sectors it is likely to degrade further. Climate change could add to the problem. Agriculture is the … Read More

Water quality series: What do you think? - Waiology

Dec 19, 2013

By Daniel Collins We have almost finished Waiology’s series on water quality, with 25 articles running from the science to solutions. I would now like to take the time to ask what you think about the series and Waiology in general. Please take a few moments to answer the following survey. All 12 questions are optional. It would be of considerable help in shaping how Waiology serves you in the future. Individual feedback will be kept anonymous and pooled results will be shared on Waiology depending on sample size. And you can always contact me directly. Thanks! [contact-form-7 404 "Not Found"] … Read More

Better water quality won’t happen overnight … but it must happen - Waiology

Dec 18, 2013

By Jenny Webster-Brown If we cannot stop ongoing water quality degradation, and effectively restore degraded water environments, we stand to lose much that we value about New Zealand and our way of life. We will lose recreational opportunities, fisheries and our reputation for primary produce from a “clean” environment. We will lose functioning ecosystems, the ecosystem services they provide and the beauty of our iconic water features. We will have to pay for increasingly higher technology to treat drinking, stock and even irrigation water … like so many drier, more populous or older nations, who have long since lost their natural water amenities. This is not what we have known, or what we wish for our children, or their children. To improve water quality, we need only three things: the will, the means and the time. This is the … Read More

How much dairying is too much in terms of water quality? - Waiology

Dec 17, 2013

By Daniel Collins On 21 November the Parliamentary Commissioner for the Environment, Jan Wright, released her second report on water quality. It warned that business-as-usual dairy expansion by 2020 would leave our lakes and rivers more degraded than they are now, even with improved mitigation. I’d now like to re-cap what the report concluded, how it got there, and how it was received. The report The purpose of the report was to illustrate how land use change could affect future nutrient runoff – nitrogen and phosphorus – based on a simple, business-as-usual scenario for 2020. Motu used a combined economics-land use model called LURNZ to project what land use changes are likely by 2020, driven by commodity process and knowledge of land use practices and landscape characteristics. Sheep and beef farming were expected to give way to … Read More

Impacts of climate change on water quality - Waiology

Dec 16, 2013

By Daniel Collins Climate change goes beyond warmer weather and more extreme floods and droughts. Effects are expected to include changes to the water quality of our rivers and lakes as well. This has implications for the vulnerability and sensitivity of freshwater ecosystems, as well as water quality limit-setting and catchment nutrient management. These issues, and more, were discussed at a Department of Conservation workshop held last week on the implications of climate change for freshwater conservation. Middle-of-the-road projections of climate change indicate a rise of about 2°C in average temperatures across New Zealand by 2080-2099 compared with 1980-1999.One of the most important aspects of water quality is temperature, and as the air warms so too will the water. New Zealand has already seen an increase in air temperature of about 1°C over the last century; over … Read More

Understanding groundwater quality – why it’s not easy - Waiology

Dec 11, 2013

By Chris Daughney and Magali Moreau Groundwater resources are very important for New Zealand. Groundwater supplies about a third of our abstractive water needs and an even greater proportion of the water required by the agricultural sector. There is understandably much concern about groundwater quality, particularly in terms of nitrate. High concentrations of nitrate in groundwater that is used for drinking can impair oxygen transport through the bloodstream, particularly in infants. High concentrations can also pose risks to aquatic ecosystems where nitrate-rich groundwater discharges to rivers, lakes and estuaries. So what is the state of health of New Zealand’s aquifers, as far as nitrate goes? There are a couple of reasons why this question is not easy to answer. The first challenge is to determine the concentration of nitrate that we should expect in the absence of human … Read More

Vague expectations get vague results: Freshwaters need targets - Waiology

Dec 09, 2013

By Mike Scarsbrook You’ll have heard this saying before. You may have even used it as an excuse when talking to your boss at the end of the year. It is equally valid in managing our water resources. If we cannot provide clarity on what we are trying to achieve, how can we expect anyone to make effective decisions and change behaviours? What should a waterbody draining a highly modified catchment look like? Should it be physically, chemically and biologically indistinguishable from a paired waterbody in an unmodified catchment? Should it be swimmable and fishable? Should it achieve environmental bottom lines, but no more? Should it remain in its current state, or move to an agreed, alternate state? Over what timeframes should change occur? These are not questions for scientists, regional council staff, or economists to answer. They need … Read More

How does agriculture affect New Zealand’s water quality? - Waiology

Dec 05, 2013

By Bob Wilcock About 40% of the land area of New Zealand is in some form of agriculture. Sheep and beef farming are the most extensive (33%) followed by dairy farming at 6%, and the remainder being horticulture and cropping. Based on a large number of comparative land use studies we have a good understanding of how agriculture affects water quality and know that about 97% of the nutrient loads entering our freshwaters are from diffuse sources, in contrast with point-sources such as pipes and wastewater discharges. Effluent from a cowshed over 1 km away. (J. Horrox)Pastoral land use contributes three principal pollutant types: the nutrients nitrogen (N) and phosphorus (P), sediment, and faecal microbes. Nutrient enrichment of waterways can lead to unwanted growth of plants (waterweeds and algae). Excess sediment may cause siltation, impair oxygen transfer processes … Read More

Estuary water quality for ecosystem health and recreation, Christchurch - Waiology

Dec 04, 2013

By Lesley Bolton-Ritchie The quality of the water in an estuary influences the health, abundance and survival of the plants and animals that live in or pass through it and the suitability of estuary water for contact recreation. For the plants and animals it is the concentration of toxicants and oxygen in the water that can affect the survival of species and excessive nutrient concentrations can affect the growth of nuisance macroalgae, phytoplankton and microphytobenthos. For contact recreation it is the concentration of faecal indicator bacteria and hence the likely presence of pathogens that can affect human health. Aerial view of the Estuary of the Heathcote and Avon Rivers/IhutaiRed areas – Coastal AE water, the remainder of the estuary is classified Coastal CR water.The following is a case study on water quality in the Estuary of the … Read More