Concentration-discharge patterns in a small urban headwater stream in a seasonally dry water-limited tropical environment

Gwenzi, Willis; Chinyama, Shyleen R; Togarepi, Sydney

doi:10.1016/j.jhydrol.2017.04.029

Cited by 14 publications

(17 citation statements)

References 49 publications

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“…Numerous studies have demonstrated that most dissolved solute concentrations negatively correlate with discharge, which can be represented as a power‐law function (Ali et al, 2017; Clow & Mast, 2010; Diamond & Cohen, 2018; Godsey, Kirchner, & Clow, 2009; Gwenzi, Chinyama, & Togarepi, 2017; Kim, Dietrich, Thurnhoffer, Bishop, & Fung, 2017; Koger, Newman, & Goering, 2018; Musolff, Schmidt, Selle, & Fleckenstein, 2015; Rose, Karwan, & Godsey, 2018; Rue et al, 2017; Singley et al, 2017):

C = a \times Q^{b},

where a is a constant, and b reflects the index of the deviation from chemostatic behaviour (Clow & Mast, 2010). When b is close to 0, there is a weak relationship between solute concentrations and discharge, implying chemostatic behaviour (Godsey et al, 2009); when b > 0, solute concentrations increase with increasing discharge (Musolff et al, 2015); however, when b = −1, the solute contents decrease with increasing discharge, when Q is the only control on C (Godsey et al, 2009).…”

Section: Discussionmentioning

confidence: 99%

Hydrological regulation of chemical weathering and dissolved inorganic carbon biogeochemical processes in a monsoonal river

Liu

Zhong

Ding

et al. 2020

Hydrological Processes

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To better understand the mechanisms relating to hydrological regulations of chemical weathering processes and dissolved inorganic carbon (DIC) behaviours, high-frequency sampling campaigns and associated analyses were conducted in the Yu River, SouthChina. Hydrological variability modifies the biogeochemical processes of dissolved solutes, so major ions display different behaviours in response to discharge change. Most ions become diluted with increasing discharge because of the shortened reactive time between rock and water under high-flow conditions. Carbonate weathering is the main source of major ions, which shows strong chemostatic behaviour in response to changes in discharge. Ions from silicate weathering exhibit a significant dilution effect relative to the carbonate-sourced ions. Under high temperatures, the increased soil CO 2 influx from the mineralisation of organic material shifts the negative carbon isotope ratios of DIC (δ 13 C DIC ) during the high-flow season. The δ 13 C DIC values show a higher sensitivity than DIC contents in response to various hydrological conditions. Results from a modified isotope-mixing model (IsoSource) demonstrate that biological carbon is a dominant source of DIC and plays an important role in temporal carbon dynamics. Furthermore, this study provides insights into chemical weathering processes and carbon dynamics, highlighting the significant influence of hydrological variability to aid understanding of the global carbon cycle.

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C = a \times Q^{b},

Section: Discussionmentioning

confidence: 99%

Hydrological regulation of chemical weathering and dissolved inorganic carbon biogeochemical processes in a monsoonal river

Liu

Zhong

Ding

et al. 2020

Hydrological Processes

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“…poral resolution of water quality observations ranges namely from weekly (Duncan et al, 2017a, b;Gwenzi et al, 2017;Moatar et al, 2017;Wymore et al, 2017) to 14-day (Hunsaker and Johnson, 2017) to monthly (Basu et al, 2010;Thompson et al, 2011;Musolff et al, 2015;Mora et al, 2016;Moatar et al, 2017) or even coarser resolution (Godsey et al, 2009). In fact, only very rarely higher-frequency databases are collected and thus analyzed (e.g., Neal et al, 2012Neal et al, , 2013von Freyberg et al, 2017).…”

Section: Study Sitesmentioning

confidence: 99%

“…One emerging postulate is that concentration-discharge (C-Q) relations represent the quantitative expression of the interaction between catchment geomorphology, land use, hydrological processes, and the solute releases, thus reflecting in lumped form the complex mixing process taking place along flow paths of variable lengths and residence time (Chorover et al, 2017). Therefore, C-Q relations have been studied with reference to hydrological variables, e.g., hydrologic connectivity and residence time (Herndon et al, 2015;Baronas et al, 2017;Duncan et al, 2017a;Gwenzi et al, 2017;Torres et al, 2017); biological processes (Duncan et al, 2017a); catchment characteristics, e.g., catchment topography, land use, catchment size, and lithological properties (Musolff et al, 2015;Diamond and Cohen, 2017;Hunsaker and Johnson, 2017;Moatar et al, 2017;Wymore et al, 2017); and anthropic activities (Basu et al, 2010;Thompson et al, 2011;Musolff et al, 2015;Baronas et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

“…This storage of nutrients might have long-memory effects, and it was considered to buffer the variability in con-centrations in streams, leading to the emergence of biogeochemical stationarity (Basu et al, 2011). However, biogeochemical stationarity has been questioned outside of agriculturally impacted catchments (Thompson et al, 2011), and a unifying theory explaining catchment-specific C-Q behavior is not available yet, considering that solutes can show different behaviors in relation to landscape heterogeneity (Herndon et al, 2015) and to the spatial and temporal scales of measurement (Gwenzi et al, 2017). Therefore, approaching the study of solute export and C-Q relations requires the separate analysis of several solutes in as many catchments as possible with the aim of finding, at least, some general behavior that can be characteristic of a given region or solute.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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

Botter

Burlando

Fatichi

2019

Hydrol. Earth Syst. Sci.

103

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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.

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“…Previous studies have shown that hydrological controls on streamwater chemistry are mostly invariant on time scales of weeks to months; for example, Gwenzi et al (2017) found similar cQ behavior for weekly to monthly sampling frequencies, and Godsey et al (2019) found similar cQ behavior in weekly/monthly grab samples and in year-to-year variations in annual average concentrations. Other studies have also shown that long-term average cQ behavior is relatively independent of the 435 sampling frequency (e.g., Bieroza et al, 2018).…”

Section: A Classification Scheme For Cq Relationships In the Erlenbmentioning

confidence: 84%

Concentration-discharge relationships vary among hydrological events, reflecting differences in event characteristics

Knapp

Freyberg

Kiewiet

et al. 2020

Preprint

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Studying the response of streamwater chemistry to changes in discharge can provide valuable insights into how 10 catchments store and release water and solutes. Previous studies have determined concentration-discharge (cQ) relationships from long-term, low-frequency data of a wide range of solutes. These analyses, however, provide little insight into the coupling of solute concentrations and flow during individual hydrologic events. Event-scale cQ relationships have rarely been investigated across a wide range of solutes and over extended periods of time, and thus little is known about differences and similarities between event-scale and long-term cQ relationships. Differences between event-scale and long-term cQ behavior 15 may provide useful information about the processes regulating their transport through the landscape.Here we analyze cQ relationships of 14 different solutes, ranging from major ions to trace metals, as well as electrical conductivity, in the Swiss Erlenbach catchment. From a 2-year time series of sub-hourly solute concentration data we determined long-term cQ relationships for each solute and compared them to cQ relationships of 30 individual events. The 20 long-term cQ behavior of groundwater-sourced solutes was representative of their cQ behavior during hydrologic events. Other solutes, however, exhibited very different cQ patterns at the event and long-term scale. This was particularly true for trace metals as well as atmospheric and/or biologically active solutes, many of which exhibited highly variable cQ behavior from one event to the next. Most of this inter-event variability in cQ behavior can be explained by factors such as catchment wetness, season, event size, input concentrations, and event-water contributions. We present an overview of the processes regulating 25 different groups of solutes, depending on their origin in and pathways through the catchment. Our analysis thus provides insight into controls on solute variations at the hydrologic event scale.

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Concentration-discharge patterns in a small urban headwater stream in a seasonally dry water-limited tropical environment

Cited by 14 publications

References 49 publications

Hydrological regulation of chemical weathering and dissolved inorganic carbon biogeochemical processes in a monsoonal river

Hydrological regulation of chemical weathering and dissolved inorganic carbon biogeochemical processes in a monsoonal river

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

Concentration-discharge relationships vary among hydrological events, reflecting differences in event characteristics

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