scholarly journals Establishment of reference or baseline conditions of chemical indicators in New Zealand streams and rivers relative to present conditions

2013 ◽  
Vol 64 (5) ◽  
pp. 387 ◽  
Author(s):  
R. W. McDowell ◽  
T. H. Snelder ◽  
N. Cox ◽  
D. J. Booker ◽  
R. J. Wilcock
Keyword(s):  
Water Quality ◽  
New Zealand ◽  
Natural Variation ◽  
Reference Conditions ◽  
Nitrogen And Phosphorus ◽  
Streams And Rivers ◽  
Ecological Benefit ◽  
Chemical Indicators ◽  
Anthropogenic Contribution ◽  
Reactive Phosphorus

The management of streams and rivers can be aided by knowledge of reference conditions. Data from >1000 sites across New Zealand was used to develop a technique to estimate median ammoniacal-N, clarity, Escherichia coli, filterable reactive phosphorus, nitrate-N, suspended solids, and total nitrogen and phosphorus values under reference conditions for streams and rivers as classified by the River Environment Classification (REC). The REC enabled us to account for natural variation in climate, topography and geology when estimating reference conditions. Values for minimally disturbed sites (i.e. <5% in intensive agriculture) were generally within the confidence limits for estimated reference values. Metrics that described: (1) the percentage of anthropogenic contribution to analyte values; and (2) the degree of enrichment beyond the reference conditions, showed that lowland sites classified as warm-wet, warm-dry or cool-dry exhibited the greatest anthropogenic input and enrichment. The consideration of natural variation by REC class informs the setting of water quality objectives through avoiding water quality limits or targets that are either too restrictive, and impossible to meet (e.g. below reference conditions), or too high, such that they have little ecological benefit. We recommend reference conditions be considered by regulatory authorities when assessing water quality impacts, objectives and limits.

scholarly journals Water quality in low‐elevation streams and rivers of New Zealand: Recent state and trends in contrasting land‐cover classes

2004 ◽  
Vol 38 (2) ◽  
pp. 347-366 ◽  
Author(s):  
Scott T. Larned ◽  
Mike R. Scarsbrook ◽  
Ton H. Snelder ◽  
Ned J. Norton ◽  
Barry J. F. Biggs
Keyword(s):  
Water Quality ◽  
New Zealand ◽  
Land Cover ◽  
Streams And Rivers

scholarly journals The role of alkalinity in setting water quality metrics: phosphorus standards in United Kingdom rivers

2018 ◽  
Vol 20 (10) ◽  
pp. 1361-1372
Author(s):  
Alan D. Tappin ◽  
Alba Navarro-Rodriguez ◽  
Sean D. W. Comber ◽  
Paul J. Worsfold
Keyword(s):  
Water Quality ◽  
European Union ◽  
United Kingdom ◽  
Water Framework Directive ◽  
Reference Conditions ◽  
Ecological Status ◽  
Quality Metrics ◽  
The European Union ◽  
Reactive Phosphorus

UK implementation of the European Union Water Framework Directive (for the 2015–2021 cycle) Ecological Status (ES) classification for river phosphorus is based on the calculation of reference conditions for reactive phosphorus (RP) using river alkalinity measurements.

Enterococci in the New Zealand environment: implications for water quality monitoring

1997 ◽  
Vol 35 (11-12) ◽  
pp. 325-331 ◽  
Author(s):  
S. A. Anderson ◽  
S. J. Turner ◽  
G. D. Lewis
Keyword(s):  
Water Quality ◽  
New Zealand ◽  
Water Quality Monitoring ◽  
Epidemiological Studies ◽  
High Ratio ◽  
Quality Data ◽  
Considerable Proportion ◽  
Multiple Sources ◽  
Water Quality Data ◽  
Bathing Water Quality

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.

scholarly journals Changing Land Use and Population Density Are Degrading Water Quality in the Lower Mekong Basin

Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1948
Author(s):  
Flavia Tromboni ◽  
Thomas E. Dilts ◽  
Sarah E. Null ◽  
Sapana Lohani ◽  
Peng Bun Ngor ◽  
...  
Keyword(s):  
Water Quality ◽  
Land Use ◽  
Population Density ◽  
Local Population ◽  
Reference Conditions ◽  
Mekong River ◽  
Land Use Impacts ◽  
Wet Season ◽  
Mekong Basin ◽  
Lower Mekong Basin

Establishing reference conditions in rivers is important to understand environmental change and protect ecosystem integrity. Ranked third globally for fish biodiversity, the Mekong River has the world’s largest inland fishery providing livelihoods, food security, and protein to the local population. It is therefore of paramount importance to maintain the water quality and biotic integrity of this ecosystem. We analyzed land use impacts on water quality constituents (TSS, TN, TP, DO, NO3−, NH4+, PO43−) in the Lower Mekong Basin. We then used a best-model regression approach with anthropogenic land-use as independent variables and water quality parameters as the dependent variables, to define reference conditions in the absence of human activities (corresponding to the intercept value). From 2000–2017, the population and the percentage of crop, rice, and plantation land cover increased, while there was a decrease in upland forest and flooded forest. Agriculture, urbanization, and population density were associated with decreasing water quality health in the Lower Mekong Basin. In several sites, Thailand and Laos had higher TN, NO3−, and NH4+ concentrations compared to reference conditions, while Cambodia had higher TP values than reference conditions, showing water quality degradation. TSS was higher than reference conditions in the dry season in Cambodia, but was lower than reference values in the wet season in Thailand and Laos. This study shows how deforestation from agriculture conversion and increasing urbanization pressure causes water quality decline in the Lower Mekong Basin, and provides a first characterization of reference water quality conditions for the Lower Mekong River and its tributaries.

scholarly journals Seasonal variation of limnological features and trophic state index of two oligotrophic reservoirs of southeast Brazil

2016 ◽  
Vol 77 (2) ◽  
pp. 323-331 ◽  
Author(s):  
S. A. Oliveira ◽  
C. E. M. Bicudo
Keyword(s):  
Chlorophyll A ◽  
Reference Conditions ◽  
Water Transparency ◽  
Metropolitan Region ◽  
Trophic State Index ◽  
Nitrogen And Phosphorus ◽  
Southeast Brazil ◽  
Water Characteristics ◽  
State Index ◽  
Reactive Silica

Abstract Limnological features of two reservoirs were studied in dry (August 2013) and rainy (January 2014) periods to evaluate the water quality that supply the city of Guarulhos, southeast Brazil. Water samples were collected in three depths and the following characteristics were measured: alkalinity, dissolved O2, free and total CO2, HCO3, soluble reactive silica, dissolved and total nitrogen and phosphorus, and chlorophyll-a. Water transparency was also measured and temperature, pH and electric conductivity profiles were obtained. Great seasonal and low spatial variability of the water characteristics occurred in the reservoirs. High values of water transparency, free CO2 availability, and low of pH, soluble reactive silica and total and dissolved nutrients values were recorded at the dry period, and different conditions were found at the rainy season. The two reservoirs were characterized by low nutrients, chlorophyll-a and turbidity, and high transparency, these features being typical of oligotrophic systems. The two reservoirs still remain under low anthropogenic impact conditions, and are presently considered reference systems for the SPMR, São Paulo Metropolitan Region. The need for actions that will reduce the input of nutrients from the neighboring cities and the main tributaries of the hydrographic basin is emphasized to maintain the ecological quality of the reservoirs and their reference conditions among the SPRM reservoirs.

Sign in / Sign up

Export Citation Format

Share Document