scholarly journals Trends and seasonality in stream water chemistry in two moorland catchments of the Upper River Wye, Plynlimon

1997 ◽  
Vol 1 (3) ◽  
pp. 571-581 ◽  
Author(s):  
B. Reynolds ◽  
M. Renshaw ◽  
T. H. Sparks ◽  
S. Crane ◽  
S. Hughes ◽  
...  
Keyword(s):  
Water Chemistry ◽  
Stream Water ◽  
Base Cation ◽  
Solute Concentration ◽  
Seasonal Effects ◽  
Quality Data ◽  
Water Quality Data ◽  
Agricultural Improvement ◽  
Stream Water Chemistry

Abstract. Stream water chemistry in the Cyff and Gwy subcatchments within the headwaters of the River Wye has been monitored regularly since 1980. In the Gwy, which is a predominantly semi-natural grassland catchment, land use has remained relatively static over the monitoring period, whilst the Cyff catchment is more buffered because of base cation inputs from agricultural improvement and ground water sources. Using a variety of statistical techniques, the long-term data are examined for evidence of trends after eliminating seasonal effects. The results highlight some of the difficulties associated with the analysis of longterm water quality data which show considerable variability over a variety of timescales. Some of this variability can be explained in terms of hydrochemical responses to climatic extremes and episodic events such as large atmospheric inputs of seasalts. The long-term fluctuations in solute concentration underline the continuing need for maintaining consistent long-term monitoring at sensitive upland sites if underlying trends related to gradual changes in pollutant deposition or climate are to be detected with any certainty.

Modelling the long-term response of stream water chemistry to forestry in Galloway, Southwest Scotland

2014 ◽  
Vol 37 ◽  
pp. 396-411 ◽  
Author(s):  
R.C. Helliwell ◽  
J. Aherne ◽  
T.R. Nisbet ◽  
G. MacDougall ◽  
S. Broadmeadow ◽  
...  
Keyword(s):  
Water Chemistry ◽  
Stream Water ◽  
Stream Water Chemistry ◽  
Term Response

scholarly journals Response of Water Chemistry to Long-Term Human Activities in the Nested Catchments System of Subtropical Northeast India

Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 988 ◽  
Author(s):  
Paweł Prokop ◽  
Łukasz Wiejaczka ◽  
Hiambok Jones Syiemlieh ◽  
Rafał Kozłowski
Keyword(s):  
Trace Metals ◽  
Population Density ◽  
Water Chemistry ◽  
Chemical Element ◽  
Anthropogenic Impact ◽  
Chemical Elements ◽  
Stream Water ◽  
Stream Water Chemistry ◽  
The Tropics

The subtropics within the monsoonal range are distinguished by intensive human activity, which affects stream water chemistry. This paper aims to determine spatio-temporal variations and flowpaths of stream water chemical elements in a long-term anthropogenically-modified landscape, as well as to verify whether the water chemistry of a subtropical elevated shield has distinct features compared to other headwater areas in the tropics. It was hypothesized that small catchments with homogenous environmental conditions could assist in investigating the changes in ions and trace metals in various populations and land uses. Numerous physico-chemical parameters were measured, including temperature, pH, electrical conductivity (EC), dissolved organic carbon (DOC), major ions, and trace metals. Chemical element concentrations were found to be low, with a total dissolved load (TDS) below 52 mg L−1. Statistical tests indicated an increase with significant differences in the chemical element concentration between sites and seasons along with increases of anthropogenic impact. Human influence was clearly visible in the case of cations (Ca2+, K+, Mg2+, Na+) and anions (Cl−, HCO3−, NO3−, SO42−), compared to trace metals. The order of most abundant metals Fe > Zn > Al > Sr was the same in springs and streams, regardless of population density, land use, and season. Principal component analysis (PCA) demonstrated that major ion concentrations in stream water followed the pattern forest < cultivated land < grassland < built-up area. Surface water chemistry of the subtropical elevated shield has mixed features of tropical and temperate zones. Low concentrations of chemical elements; small seasonal differences in headwater streams; and increased concentrations of NO3−, SO42−, DOC, and Zn in the wet monsoon season are similar to those observed in the tropics. The role of long-term cultivation without chemical fertilizers in ions supply to streams is less than in other headwater areas of the tropical zone. Strong control of water chemistry in densely populated built-up areas is analogous to both tropical and temperate regions. Population density or a built-up area may be used as a proxy for the reconstruction or prediction of the anthropogenic impact on stream water chemistry in similar subtropical elevated shields.

scholarly journals Anthropogenic and catchment characteristic signatures in the water quality of Swiss rivers: a quantitative assessment

2018 ◽  
Author(s):  
Martina Botter ◽  
Paolo Burlando ◽  
Simone Fatichi
Keyword(s):  
Water Quality ◽  
Anthropogenic Impacts ◽  
Stream Water ◽  
Anthropogenic Activities ◽  
Quality Data ◽  
Anthropogenic Factors ◽  
Water Quality Data ◽  
Natural And Anthropogenic Factors

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.

scholarly journals Anthropogenic and catchment characteristic signatures in the water quality of Swiss rivers: a quantitative assessment

2019 ◽  
Vol 23 (4) ◽  
pp. 1885-1904 ◽  
Author(s):  
Martina Botter ◽  
Paolo Burlando ◽  
Simone Fatichi
Keyword(s):  
Water Quality ◽  
Anthropogenic Impacts ◽  
Stream Water ◽  
Temporal Variations ◽  
Quality Data ◽  
Anthropogenic Factors ◽  
Water Quality Data ◽  
Catchment Characteristics

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 11 Swiss catchments with the objective to discern the influence of major catchment characteristics and anthropic 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 the solute behaviors. While the anthropogenic impacts are clearly detectable in the concentration of certain solutes (i.e., Na+, Cl−, NO3, DRP), the influence of single catchment characteristics such as geology (e.g., on Ca2+ and H4SiO4), topography (e.g., on DOC, TOC, and TP), and size (e.g., on DOC and TOC) is only sometimes visible, which is also because of the limited sample size and the spatial heterogeneity within catchments. Solute variability in time is generally smaller than discharge variability and the most significant trends in time are due to temporal variations of anthropogenic rather than natural forcing. The majority of solutes show dilution with increasing discharge, especially geogenic species, while sediment-bonded solutes (e.g., total phosphorous and organic carbon species) show higher concentrations with increasing discharge. Both natural and anthropogenic factors affect 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 the 11 catchments that exhibit different natural, climatic, and anthropogenic features.

Long-term data reveal patterns and controls on stream water chemistry in a forested stream: Walker Branch, Tennessee

2012 ◽  
Vol 82 (3) ◽  
pp. 367-387 ◽  
Author(s):  
Brian D. Lutz ◽  
Patrick J. Mulholland ◽  
Emily S. Bernhardt
Keyword(s):  
Water Chemistry ◽  
Stream Water ◽  
Stream Water Chemistry ◽  
Forested Stream ◽  
Term Data

scholarly journals The hydrochemistry of the headwaters of the River Severn, Plynlimon

1997 ◽  
Vol 1 (3) ◽  
pp. 583-617 ◽  
Author(s):  
C. Neal ◽  
J. Wilkinson ◽  
M. Neal ◽  
M. Harrow ◽  
H. Wickham ◽  
...  
Keyword(s):  
Water Chemistry ◽  
Stream Water ◽  
Ammonium Phosphate ◽  
Base Cations ◽  
Quality Data ◽  
Input Output ◽  
Transition Elements ◽  
Water Quality Data ◽  
Soil System ◽  
Stream Waters

Abstract. Water quality data spanning 13 years and covering an extensive range of major, minor and trace elements in rain and stream waters at Plynlimon in mid Wales, are presented. Rainfall water chemistry is highly variable due to varying proportions of marine and pollutant derived constituents associated with patterns of atmospheric circulation. Stream waters, being composed of different proportions of waters from three chemically distinct sources at any one time (atmospheric deposition, the soil system and deeper groundwaters), are also chemically highly variable. For example, components predominantly derived from deposition such as chloride change only in response to sea-salt deposition episodes. Solutes associated with bedrock weathering such as calcium, magnesium, and alkalinity decrease with increasing flow, those associated with the upper soil layers such as aluminium, many transition metals, dissolved organic carbon and hydrogen ions increase with increasing flow. The nutrients (e.g. nitrate, boron, bromide and iodine) exhibit strong seasonal cycles associated with cycles of vegetation growth and decay. The changes in stream water chemistry resulting from tree harvesting in the Afon Hore catchment are shown to have run their course within a period of eight years. Nutrient increases in the first few years following the commencement of felling have returned to or fallen below pre-felling values. Aluminium changes are shown to be complicated by changes in nitrate and calcium. Aluminium concentrations initially increased and have fallen below their pre-felling value. Data for chloride suggest a reduction in capture of dry and mist deposition; this indicates the importance of understanding reduced deposition as a result of felling. Felling has also affected the soil micro-climate which experiences greater fluctuations in temperature and an increase in the concentration of constituents associated with organic matter. Input-output mass balance estimates show that atmospheric inputs of many constituents are retained strongly by the catchment (e.g. ammonium, phosphate, barium, boron, lead and iodine). In contrast, many of the transition elements as well as divalent base cations, aluminium and alkalinity show a net release from the catchment. Conservative constituents such as chloride and sodium show a net input-output balance.

scholarly journals Detecting dominant changes in irregularly sampled multivariate water quality data sets

2018 ◽  
Vol 22 (8) ◽  
pp. 4401-4424
Author(s):  
Christian Lehr ◽  
Ralf Dannowski ◽  
Thomas Kalettka ◽  
Christoph Merz ◽  
Boris Schröder ◽  
...  
Keyword(s):  
Water Quality ◽  
Stream Water ◽  
Shallow Groundwater ◽  
Irregular Sampling ◽  
Quality Data ◽  
Data Sets ◽  
Water Quality Data ◽  
Data Set ◽  
Sampling In Space

Abstract. Time series of groundwater and stream water quality often exhibit substantial temporal and spatial variability, whereas typical existing monitoring data sets, e.g. from environmental agencies, are usually characterized by relatively low sampling frequency and irregular sampling in space and/or time. This complicates the differentiation between anthropogenic influence and natural variability as well as the detection of changes in water quality which indicate changes in single drivers. We suggest the new term “dominant changes” for changes in multivariate water quality data which concern (1) multiple variables, (2) multiple sites and (3) long-term patterns and present an exploratory framework for the detection of such dominant changes in data sets with irregular sampling in space and time. Firstly, a non-linear dimension-reduction technique was used to summarize the dominant spatiotemporal dynamics in the multivariate water quality data set in a few components. Those were used to derive hypotheses on the dominant drivers influencing water quality. Secondly, different sampling sites were compared with respect to median component values. Thirdly, time series of the components at single sites were analysed for long-term patterns. We tested the approach with a joint stream water and groundwater data set quality consisting of 1572 samples, each comprising sixteen variables, sampled with a spatially and temporally irregular sampling scheme at 29 sites in northeast Germany from 1998 to 2009. The first four components were interpreted as (1) an agriculturally induced enhancement of the natural background level of solute concentration, (2) a redox sequence from reducing conditions in deep groundwater to post-oxic conditions in shallow groundwater and oxic conditions in stream water, (3) a mixing ratio of deep and shallow groundwater to the streamflow and (4) sporadic events of slurry application in the agricultural practice. Dominant changes were observed for the first two components. The changing intensity of the first component was interpreted as response to the temporal variability of the thickness of the unsaturated zone. A steady increase in the second component at most stream water sites pointed towards progressing depletion of the denitrification capacity of the deep aquifer.

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