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.

Water quality models – are they good enough for management? - Waiology

Dec 02, 2013

By Sandy Elliott Water quality models are making their way to a farm or catchment near you – so what are they, and how good are they? Models are being used in New Zealand to address water quality impacts of land use from national to farm scales. At national scale, the CLUES model was recently linked to a land-use evolution model to predict future changes in water quality in a study for the Parliamentary Commissioner for the Environment (see figure for an example of the predictions). The Freshwater Reforms propose that models be used in community deliberation processes for catchments. Down on the farm, the leaching model OVERSEER is being used under the Waikato Regional Plan Variation No 5 to regulate nutrient emissions in the Lake Taupo catchment. Predicted nitrogen yield increase from 2008 to … Read More

Emerging organic contaminants: A threat to New Zealand freshwaters? - Waiology

Nov 29, 2013

By Sally Gaw Emerging organic contaminants are a burgeoning and extremely diverse class of contaminants that are not routinely monitored and that have the potential to have adverse ecological and human health effects. Emerging organic contaminants (EOCs) include both naturally occurring and synthetic chemicals. Many of these contaminants may have been present in the environment for a long time but are only now have they become detectable due to advances in analytical chemistry. EOCs include active ingredients in personal care and domestic cleaning products, pesticides, plasticisers, pharmaceuticals, steroid hormones excreted by humans and animals, surfactants and veterinary medicines. Many EOCs are everyday chemicals in widespread use in consumer products. Much research is being devoted internationally to understanding the sources, environmental fate and adverse effects of EOCs. Discharges from wastewater treatment plants are a major source of emerging contaminants … Read More

Nitrate in Canterbury groundwater - Waiology

Nov 27, 2013

By Carl Hanson Nitrate concentrations in Canterbury groundwater have been prominent in the media recently. Headlines have included phrases like “ticking time bomb”, “scaremongering” and “freaking out much of Canterbury”. What I want to do in this article is to present the state of nitrate concentrations in Canterbury groundwater, and the trends we see in those concentrations, as objectively as I can, avoiding any emotive language. First, the concentrations. Based on the data from our regional long-term monitoring programme, which includes approximately 300 wells distributed across the region, nitrate concentrations in Canterbury groundwater fall into two groups: About 30% of the samples we collect have concentrations less than 1 mg/L (recorded as nitrate nitrogen). The rest of the samples have concentrations distributed over a broader range, with an average of about 5 to 6 mg/L and … Read More

Nuisance periphyton – too much of a good thing - Waiology

Nov 25, 2013

By John Quinn Periphyton is the name given to the community of algae that grows on river and lake beds, and it has a Dr Jekyll and Mr Hyde reputation. As thin films and short/sparse filaments – the good Dr Jekyll – it is an important fuel at the base of healthy aquatic food webs, turning nutrients and sunlight into a food for invertebrates, which are in turn food for fish and waterbirds. In the process, they reduce the nutrient levels downstream or in a lake, helping to control eutrophication. Ecologist Maurice Lock once described periphyton as the “light and energy transducer of streams”. When viewed under a microscope, the species are also stunningly beautiful. Dr Jekyll periphyton – thin films with about 10% cover by filamentous green algae. (J. Quinn)But its Mr Hyde side comes to … Read More

Overcoming obstacles to setting water quality limits - Waiology

Nov 22, 2013

By Ned Norton and Helen Rouse In the previous Waiology series on Water governance, we referred to the National Policy Statement for Freshwater Management (NPSFM) (2011) requirement to set limits for water quantity and quality. So, how are councils getting on with limit-setting? In May 2012 we surveyed planners for regional councils to find out how their current regional plans measure up against the NPSFM requirements to set limits, and found that 1 of 14 respondents said their current plan meets NPSFM requirements, 8 of 14 said their plan met requirements to some extent, and 5 of 14 said their plan did not meet NPSFM requirements. Our survey also identified a number of potential obstacles that make limit-setting difficult. Some of the most common obstacles were costs (time,staff), availability of catchment-specific data, understanding existing/baseline conditions, balancing instream … Read More

Science and policy merge in water plan - Waiology

Nov 20, 2013

By Paul Reynolds Recently the government released proposals for a national framework for setting freshwater objectives, including bottom lines for ecosystem and human health (for secondary contact). It has had an unusual reaction. For the first time in my memory, we have had stakeholders from all quarters pretty much in strenuous non-disagreement with one another – in support of the proposal. That is not a common occurrence in the policy world. In particular, it is not common in environmental policy, where complex ‘wicked’ problems predominate and people often have trouble agreeing on the problem – let alone contributing constructively to the solution. Developing the National Objectives Framework has been a challenge. It was first suggested by the independent group of water users who make up the Land and Water Forum. The government then took it up as a tool … Read More

Monitoring the diversity of NZ groundwater quality - Waiology

Nov 18, 2013

By Magali Moreau, Chris Daughney and Zara Rawlinson To date, more than 200 aquifers have been mapped across the country. These aquifers vary widely in their volumes, depths, host-rock lithologies, related geological structures, water circulation pathways and water age. Our knowledge of the individual characteristics of these aquifers grows as we gather more data through our active monitoring networks. Active monitoring of groundwater is undertaken by the National Groundwater Monitoring Programme (NGMP) and, at the regional scale, by the State of the Environment (SOE) networks. Initiated in 1990, the NGMP achieved national coverage in 1998 (currently 108 sites) and is a collaboration between GNS Science and 15 regional authorities. Groundwater samples are collected quarterly at NGMP sites and tested for more than 25 parameters using a consistent sampling protocol and suite of analytical procedures. At the regional scale, … Read More

Managing nitrogen in the Lake Taupo catchment - Waiology

Nov 13, 2013

By Bill Vant and Jon Palmer More than 10 years ago, the Waikato Regional Council became concerned about the effects of increasing catchment loads of nitrogen on the water quality of Lake Taupo. Calculations showed that most (>90%) of the manageable nitrogen entering the lake came from areas of pasture in the catchment. A variation to the Waikato Regional Plan was developed, and was finally confirmed by the Environment Court in July 2011. The Plan aims to maintain the lake’s current water quality well into the future (“by 2080”), by managing loads of nitrogen in the catchment. It aims to do this by (1) capping all manageable sources at their 2001 levels, and (2) reducing some of the manageable sources to offset much of the historic load from land development that is stored in groundwater and is thus still … Read More

Why freshwater management needs to include estuaries - Waiology

Nov 11, 2013

By Malcolm Green There is a widespread view that cumulative effects – those effects that build up over time or that occur in combination with other effects – are the Achilles heel of the Resource Management Act. Back in 2010, the Land and Water Forum, echoing previous legal commentary, argued that limits are the solution: “without limits it is hard to manage diffuse discharges… and impossible to deal with the cumulative effects on water bodies of water takes on the one hand and diffuse and direct discharges to water on the other”. In 2011, the National Policy Statement for Freshwater Management was gazetted, which requires that objectives be set for freshwater bodies that reflect a range of aspirations and values, and that limits for water quantity and quality be set to ensure that objectives are achieved. Most recently, the … Read More

Proposed national bottom lines for water quality - Waiology

Nov 08, 2013

By Daniel Collins The Government recently released a new round of freshwater reform proposals. A significant part of them included additions to the National Policy Statement for Freshwater Management with regards to water quality. The NPSFM currently directs Councils to undergo a process of setting limits for water quality degradation, but neither the process nor consistent numerical targets had been outlined. Until now. Targets that have now been proposed within the National Objectives Framework (NOF) include “national bottom lines” – thresholds of water quality attributes that good management should prevent our waterways from crossing. For Version 1 of the NOF, the proposed attributes, their limits, and implications are summarised in the table below. It is important to understand, though, that Councils are obliged to maintain or improve water quality within their regions. They cannot simply let conditions degrade … Read More