Dairying and water-quality issues in Australia and New Zealand

2015 ◽  
Vol 55 (7) ◽  
pp. 856 ◽  
Author(s):  
M. R. Scarsbrook ◽  
A. R. Melland

The scale and intensity of dairy farming can place pressure on our freshwater resources. These pressures (e.g. excessive soil nutrient concentrations and nitrogen excretion) can lead to changes in the levels of contaminants in waterways, altering the state and potentially affecting the uses and values society ascribes to water. Resource management involves putting in place appropriate responses to address water-quality issues. In the present paper, we highlight trends in the scale and extent of dairying in Australia and New Zealand and describe water-quality pressures, state, impacts and responses that characterise the two countries. In Australia and New Zealand, dairy farming has become increasingly intensive over the past three decades, although the size of Australia’s dairy herd has remained fairly static, while New Zealand’s herd and associated excreted nitrogen loads have nearly doubled. In contrast, effluent management has been improved, and farm waterways fenced, in part to reduce pressure on freshwater. However, both countries show a range of indicators of degraded water-quality state. Phosphorus and nitrogen are the most common water-quality indicators to exceed levels beyond the expected natural range, although New Zealand also has a significant percentage of waterways with faecal contaminants beyond acceptable levels for contact recreation. In New Zealand, nitrate concentrations in waterways have increased, while phosphorus and suspended sediment concentrations have generally decreased over the past decade. Water quality in some coastal estuaries and embayments is of particular concern in Australia, whereas attention in New Zealand is on maintaining quality of high-value lakes, rivers and groundwater resources, as well as rehabilitating waterbodies where key values have been degraded. In both Australia and New Zealand, water-quality data are increasingly being collated and reported but in Australia long-term trends across waterbodies, and spatially comprehensive groundwater-quality data have not yet been reported at national levels. In New Zealand, coastal marine systems, and particularly harbours and estuaries, are poorly monitored, but there are long-term monitoring systems in place for rivers, groundwater and lakes. To minimise pressures on water quality, there is a high reliance on voluntary and incentivised practice change in Australia. In New Zealand, industry-led practice change has been important over the past decade, but regulated environmental limits for dairy farmers are increasing. Dairy industries in both countries have set targets for reducing pressures through sustainability frameworks and accords. To address future drivers such as climate change and increasing domestic and international market demand for sustainability credentials, definitions of values and appropriate targets for waterbodies draining agricultural landscapes will be required. Environmental limits (both natural and societal) will constrain future growth opportunities for dairying and research into continued growth within limits remains a priority in both countries.

1997 ◽  
Vol 35 (11-12) ◽  
pp. 325-331 ◽  
Author(s):  
S. A. Anderson ◽  
S. J. Turner ◽  
G. D. Lewis

Faecal enterococci ecology outside the host is of great relevance when using these organisms as indicators of water quality. As a complement to New Zealand epidemiological studies of bathing water quality and health risk, a study of the environmental occurrence of these organisms has been undertaken. Specific concerns over the use of enterococci derive from the unique situation in New Zealand which has few chlorinated sewage effluents, a high ratio of grazing animals to humans, and significant inputs of animal processing effluents into the environment. Human and animal faecal wastes are the main sources, with 106–107cfu/100ml found in human sewage. Analysis of domestic and feral animal faeces found enterococci in the range of 101–106cfu/g with considerable variation between species. The latter observations support the notion that a considerable proportion of the load in urban/rural catchments and waterways (typically 102–103 enterococci cfu/100ml) is derived from non-human sources. Previous studies of enterococci quiescence in marine/fresh waters indicate that they enter a non-growth phase, exposure to sunlight markedly reducing culturability on selective and non-selective media. Enterococci were also found to survive/multiply within specific non-faecal environments. Enterococci on degrading drift seaweed at recreational beaches exceeded seawater levels by 2–4 orders of magnitude, suggesting that expansion had occurred in this permissive environment with resultant potential to contaminate adjacent sand and water. These studies suggest that multiple sources, environmental persistence, and environmental expansion of enterococci within selected niches add considerable complexity to the interpretation of water quality data.


2019 ◽  
Vol 11 (23) ◽  
pp. 2875
Author(s):  
Fajar Setiawan ◽  
Bunkei Matsushita ◽  
Rossi Hamzah ◽  
Dalin Jiang ◽  
Takehiko Fukushima

Most of the lakes in Indonesia are facing environmental problems such as eutrophication, sedimentation, and depletion of dissolved oxygen. The water quality data for supporting lake management in Indonesia are very limited due to financial constraints. To address this issue, satellite data are often used to retrieve water quality data. Here, we developed an empirical model for estimating the Secchi disk depth (SD) from Landsat TM/ETM+ data by using data collected from nine Indonesian lakes/reservoirs (SD values 0.5–18.6 m). We made two efforts to improve the robustness of the developed model. First, we carried out an image preprocessing series of steps (i.e., removing contaminated water pixels, filtering images, and mitigating atmospheric effects) before the Landsat data were used. Second, we selected two band ratios (blue/green and red/green) as SD predictors; these differ from previous studies’ recommendation. The validation results demonstrated that the developed model can retrieve SD values with an R2 of 0.60 and the root mean square error of 1.01 m in Lake Maninjau, Indonesia (SD values ranged from 0.5 to 5.8 m, n = 74). We then applied the developed model to 230 scenes of preprocessed Landsat TM/ETM+ images to generate a long-term SD database for Lake Maninjau during 1987–2018. The visual comparison of the in situ-measured and satellite estimated SD values, as well as several events (e.g., algal bloom, water gate open, and fish culture), showed that the Landsat-based SD estimations well captured the change tendency of water transparency in Lake Maninjau, and these estimations will thus provide useful data for lake managers and policy-makers.


2020 ◽  
Vol 60 (1) ◽  
pp. 67
Author(s):  
Ranvir Singh ◽  
David J. Horne

Context Dairy farming will be increasingly scrutinised for its environmental impacts, in particular for its impacts on freshwater quality in New Zealand and elsewhere. Management and mitigation of high nitrate losses is one of the greatest water-quality challenges facing dairy farming in New Zealand and other countries. Management of critical flow pathways and nitrate-attenuation capacity could offer potential solutions to this problem and help maintain dairy-farming productivity, while reducing its water-quality impacts. Aims The present paper reviewed the key water-quality issues faced by dairy farming and assessed potential of emerging edge-of-paddock technologies, and catchment-scale nutrient-attenuation practices, to reduce nitrate losses from dairy farming to receiving water bodies. Methods We developed a conceptual catchment-scale modelling analysis assessing potential natural and built attenuation of nitrate losses from dairy farming in the Tararua and Rangitikei catchments (located in the lower part of the North Island, New Zealand). Key results This exploratory analysis suggests that a reduction of greater than 25% in the river nitrate loads from dairy-farming areas could potentially be achieved by spatially aligning dairy land with areas of high subsurface nitrate-attenuation capacity, and by managing critical flow pathways using innovative edge-of-field technologies such as controlled drainage, drainage-water harvesting for supplemental irrigation, woodchip bioreactors, and constructed wetlands in the study catchments. Conclusions The research findings highlighted the potential to better understand, map and effectively utilise existing natural and new built-in nitrate-attenuation capacity to significantly reduce water-quality impacts from dairy farming across environmentally sensitive agricultural catchments. This knowledge and tools could help farmers close the gap between what can be achieved with current, in-field mitigation practises and the nitrogen-loss allocation imposed by regulatory authorities. Implications However, the research findings presented here are based on a coarse-scale, conceptual modelling analysis, and therefore further research is recommended to develop tools and practices to better understand, map and effectively utilise existing natural and new built-in nitrogen attenuation capacity at farm-scale to achieve productive and environmentally friendly pastoral dairy farming across agricultural landscapes.


2018 ◽  
Author(s):  
Martina Botter ◽  
Paolo Burlando ◽  
Simone Fatichi

Abstract. The hydrological and biogeochemical response of rivers carries information about solute sources, pathways, and transformations in the catchment. We investigate long-term water quality data of eleven Swiss catchments with the objective to discern the influence of catchment characteristics and anthropogenic activities on delivery of solutes in stream water. Magnitude, trends and seasonality of water quality samplings of different solutes are evaluated and compared across catchments. Subsequently, the empirical dependence between concentration and discharge is used to classify different solute behaviors. Although the influence of catchment geology, morphology and size is sometime visible on in-stream solute concentrations, anthropogenic impacts are much more evident. Solute variability is generally smaller than discharge variability. The majority of solutes shows dilution with increasing discharge, especially geogenic species, while sediment-related solutes (e.g. Total Phosphorous and Organic Carbon species) show higher concentrations with increasing discharge. Both natural and anthropogenic factors impact the biogeochemical response of streams and, while the majority of solutes show identifiable behaviors in individual catchments, only a minority of behaviors can be generalized across catchments that exhibit different natural, climatic and anthropogenic features.


2021 ◽  
Author(s):  
◽  
Jakob Parrish

<p>Decreasing water quality of lakes as a result of anthropogenic landuse and specifically agricultural intensification is well documented in New Zealand. However, monitoring records of lake health are typically short, only commencing once signs of lake deterioration are observed. The shortness of the instrumental record precludes a detailed understanding of the relationship between landuse change, lake ecosystem trajectories and the effectiveness of mitigation strategies such as riparian planting. Paleolimnological reconstruction from sediment cores has the potential to develop high-resolution time series that may extend lake monitoring centuries into the past. This thesis uses paleoenvironmental reconstruction to investigate lake ecosystem change and water quality in Lake Nganoke, Wairarapa, New Zealand as a result of landuse intensification. The primary aim of this thesis is to reconstruct the past environment of Lake Nganoke from a pre-human reference state to the current day to assess: 1) how increased nutrient fluxes associated with landuse intensification have impacted the lake ecosystem; and 2) the ability of riparian zones to buffer these fluxes. The reconstruction was achieved using a multi proxy approach with pre and post-human environments of Lake Nganoke characterised using Palynology, geochemistry, eDNA and hyperspectral scanning.  Māori land clearance was identified at ~AD 1450 (95% CI: AD 1417-1551). The appearance of Pinus pollen and increases in fertilisation and stocking rates placed European arrival at ~AD 1850 (95% CI: 1809 - 1870), while intensification of agricultural landuse occurred post ~AD 1950 (95% CI: 1948 - 1964). The prehuman environment of Lake Nganoke experienced little change, with the catchment dominated by tall trees and likely heavily forested. The lake ecosystem and water quality during this time showed little to no change, with algal productivity likely driven by a constant input of natural nutrients. Post Māori arrival, algal productivity was reduced suggesting an increase in water quality likely driven by added lake marginal plants providing a riparian buffer to terrestrially derived nutrients. Lake productivity increased dramatically post European arrival ~AD 1850, coeval with an increase in sediment Cd, suggesting that fertilisation may have driven a decline in water quality. Further increases in fertilisation and stocking rates indicate additional agricultural nutrient fluxes entering Lake Nganoke in AD 1950 when agriculture intensified. Abundances in denitrifying Gammaproteobacteria indicate increases in nutrient loading while bloom forming Cyanobacteria peak ~AD 2000 before declining till present. Riparian planting following Māori arrival appears sufficient to buffer the lake against increased terrestrial nutrient fluxes associated with land clearing. However, a riparian zone that covers the majority of the catchment post European settlement was inadequate in altering the lake’s degrading ecosystem and water quality trajectory.</p>


Author(s):  
David Paterson ◽  
Simon Brown

This paper examines labour force participation trends in New Zealand, how we compare to the rest of the OECD and how participation and economic growth might be affected in the future by population ageing. Participation has risen significantly over the past 20 years despite an increase in the average age of the working­age population. We have looked at how participation has changed by age, gender and ethnicity. By contrast, average hours worked has declined over the past 20 years and we consider the reasons for that. Population ageing means the recent growth seen in labour force participation is likely to come to an end, with the participation rate projected to decline over the medium term. Falling participation will have a dampening effect on economic growth. We have investigated the impact of declining participation on gross domestic product using official labour force projections and identified a range of scenarios for what participation might look like in the year 2029. In each scenario, we discuss the impact on economic growth. Most other OECD countries are in a similar situation to us with respect to population ageing. We have looked at the latest Australian projections for economic growth in the long term and the increased growth in New Zealand’s productivity that would be necessary to begin to close the gap on Australia.


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