Effects of streamflow regime on the concentration-flow (CQ) relationships across climate zones: a study across the Australian continent

2021 ◽  
Author(s):  
Clément Duvert ◽  
Danlu Guo ◽  
Camille Minaudo ◽  
Rémi Dupas ◽  
Anna Lintern ◽  
...  
Keyword(s):  
Water Quality ◽  
Temporal Variation ◽  
Spatial And Temporal Variation ◽  
Phosphorus Species ◽  
Climate Zones ◽  
Bayesian Hierarchical ◽  
Australian Continent ◽  
Data Driven Approach ◽  
Total Variability ◽  
Reactive Phosphorus

<p>Understanding the spatial and temporal variation of concentration-flow (CQ) relationships is valuable to enhance understanding of the key processes that drive changes in catchment water quality. This study used a data-driven approach to understand how the CQ relationship is influenced by catchment flow regimes (baseflow versus runoff dominated) throughout the Australian continent. To summarize the CQ relationship, we focus on the b exponent in a power-law relationship (C=aQ<sup>b</sup>). We considered six commonly monitored constituents, namely, electrical conductivity (EC), total phosphorus (TP), filterable reactive phosphorus (FRP), total suspended solids (TSS), nitrate–nitrite (NO<sub>x</sub>) and total nitrogen (TN), at a total of 251 catchments in Australia. A novel Bayesian hierarchical model was developed to assess a) the impacts of flow regime on CQ relationships, both across catchments (spatial variation) and within individual catchments (temporal variation); and b) how these impacts vary across five typical Australian climate zones – arid, Mediterranean, temperate, sub-tropical and tropical.</p><p>We found that for individual constituents: 1) spatial variations in CQ relationships are clearly influenced by the catchment-level baseflow contribution, and these influences differ with climate regions; 2) across climate zones, runoff-dominated catchments (i.e. with low baseflow contribution) have relatively stable CQ relationships, while groundwater-dominated catchments (i.e. with high baseflow contribution) have highly variable CQ patterns across climate zones; 3) within individual catchments, the variations in instantaneous baseflow contribution have no systematic and consistent effect on the CQ relationships. The influence of catchment baseflow contribution on CQ relationships has potential to be used to predict catchment water quality across Australia, with over half the total variability in concentration of sediment, salt and phosphorus species explained by variations in catchment-level baseflow contribution.</p>

scholarly journals Synthesizing the impacts of baseflow contribution on C-Q relationships across Australia using a Bayesian Hierarchical Model

2021 ◽  
Author(s):  
Danlu Guo ◽  
Camille Minaudo ◽  
Anna Lintern ◽  
Ulrike Bende-Michl ◽  
Shuci Liu ◽  
...  
Keyword(s):  
Water Quality ◽  
Hierarchical Model ◽  
Spatial Scales ◽  
Bayesian Hierarchical Model ◽  
Spatial And Temporal Variation ◽  
Strong Impact ◽  
Climate Zones ◽  
Bayesian Hierarchical ◽  
Flow Pathways ◽  
The Impact

Abstract. The spatial and temporal variation of concentration-discharge (C-Q) relationships inform solute and particulate export processes. Previous studies have shown that the extent to which baseflow contributes to streamflow can affect C-Q relationships in some catchments. However, these patterns have not yet been investigated across large spatial scales. To address this, the study aims to assess how baseflow contributions, as defined by the median catchment baseflow index (BFI_m), influence C-Q slopes across 157 catchments in Australia spanning five climate zones. This study focuses on six water quality variables: electrical conductivity (EC), total phosphorus (TP), soluble reactive phosphorus (SRP), total suspended solids (TSS), nitrate–nitrite (NOx) and total nitrogen (TN). The impact of baseflow contribution is explored with a novel Bayesian hierarchical model. We found that BFI_m has a strong impact on C-Q slopes. C-Q slopes are largely positive for nutrient species (NOx, TN, SRP and TP) and are steeper in catchments with higher BFI_m across all climate zones (for TN, SRP and TP). On the other hand, we also found a generally higher variation in instantaneous BFI for catchments with high BFI_m. Thus, the steeper C-Q slopes found in catchments with high BFI_m may be a result of a larger variation in water sources and flow pathways between low (baseflow-dominated) and high (quickflow-dominated) flow conditions. In contrast, catchments with low BFI_m may have more homogeneous flow pathways at both low and high flows, resulting in less variable concentrations and thus a flatter C-Q slope. Our model can explain over half of the observed variability in concentration of TSS, EC and P species across all catchments (93 % for EC, 63 % for TP, 63 % for SRP, and 60 % for TSS), while being able to predict C-Q slopes across space by BFI_m. This indicates that our parsimonious model has potential for predicting the C-Q slopes for catchments in different climate zones, and thus improving the predictive capacity for water quality across Australia.

scholarly journals Spatio-temporal variation analysis of hydrochemical characteristics in the Luanhe River Basin, China

2013 ◽  
Vol 67 (6) ◽  
pp. 1332-1338 ◽  
Author(s):  
Ying Xie ◽  
Xuyong Li ◽  
Huiliang Wang ◽  
Wenzan Li
Keyword(s):  
Water Pollution ◽  
Water Quality ◽  
Temporal Variation ◽  
River Water ◽  
River Basin ◽  
Pollution Control ◽  
Spatial And Temporal Variation ◽  
Hydrochemical Characteristics ◽  
Water Pollution Control ◽  
Luanhe River Basin

The analysis of river pollution and assessment of spatial and temporal variation in hydrochemistry are essential to river water pollution control in the context of rapid economic growth and growing pollution threats in China. In this study, we focused on hydrochemical characteristics of the Luanhe River Basin (China) and evaluation of 12 hydrochemical variables obtained from 32 monitoring stations during 2001–2010. In each study year, the streams were monitored in the three hydrological periods (April, August, and October) to observe differences in the impacts of agricultural activity and rainfall pattern. Multivariate statistical methods were applied to the data set, and the river water hydrochemical characteristics were assessed using the water quality identification index (WQIIM). The results showed that parameters had variable contribution to water quality status in different months except for ammonia nitrogen (NH4-N) and total nitrogen (TN), which were the most important parameters in contributing to water quality variations for all three periods. Results of WQIIM revealed that 18 sites were classified as 'meeting standard' while the other 14 sites were classified as 'not meeting standard', with most of the seriously polluted sites located in urban area, mainly due to discharge of wastewater from domestic and industrial sources. Sites with low pollution level were located primarily in smaller tributaries, whereas sites of medium and high pollution levels were in the main river channel and the larger tributaries. Our findings provide valuable information and guidance for water pollution control and water resource management in the Luanhe River Basin.

scholarly journals Spatial and temporal variation of dissolved heavy metals in the Lijiang River China: Implication of rainstorm on drinking water quality

2021 ◽  
Author(s):  
Liming Deng ◽  
Asfandyar Shahab ◽  
He Xiao ◽  
Jieyue Li ◽  
Saeed Rad ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Water Quality ◽  
Drinking Water ◽  
Health Risk ◽  
Temporal Variation ◽  
High Flow ◽  
Anthropogenic Sources ◽  
Spatial And Temporal Variation ◽  
Lijiang River ◽  
Dissolved Heavy Metals

Abstract Lijiang River is an essential drinking water source and natural scenery in the Guilin City. For the first time, implications of rainstorm were taken into consideration by investigating spatial and temporal variation of dissolved heavy metals (HMs) in the Lijiang River water. A total of 68 water samples were collected during low flow (normal) season and high flow (rainstorm) season from 34 sampling sites. Dissolved HMs including Cr, Mn, Co, Cu, Zn, As, Cd, Sb, and Pb were found to meet the respective drinking water standards, while higher concentration was observed after the rainstorm season, except for Cr. Multivariate statistical analysis showed Co, Cu, Cr, Zn, Sb, and Pb in normal season are mainly controlled by anthropogenic sources. Furthermore, higher concentration of Mn, Cu, Cd, Pb, Co and Zn during the high flow season is attributed to rainstorm. The water quality index (WQI) showed good grades, and comparatively lower in rainstorm season. The results of health risk assessment revealed that HMs in Lijiang River pose limited health risk, however, As poses potential health risk during rainstorm season. It is suggested to adopt preventive measures in mining activities and industrial waste-water discharge at the river’s upstream and downstream.

Temporal and spatial variability in seedling dynamics: a cross-site comparison in four lowland tropical forests

2008 ◽  
Vol 24 (1) ◽  
pp. 9-18 ◽  
Author(s):  
Margaret R. Metz ◽  
Liza S. Comita ◽  
Yu-Yun Chen ◽  
Natalia Norden ◽  
Richard Condit ◽  
...  
Keyword(s):  
Temporal Variation ◽  
Tropical Forests ◽  
Spatial And Temporal Variation ◽  
Monitoring Methods ◽  
Bayesian Hierarchical ◽  
Seedling Demography ◽  
Temporal And Spatial Variability ◽  
Seedling Dynamics ◽  
Lowland Forests

Abstract:Spatial and temporal variation in seedling dynamics was assessed using records of community-wide seedling demography collected with identical monitoring methods at four tropical lowland forests in Panama, Malaysia, Ecuador and French Guiana for periods of between 3 and 10 y. At each site, the fates of between 8617 and 391 777 seedlings were followed through annual censuses of the 370–1008 1-m2 seedling plots. Within-site spatial and inter-annual variation in density, recruitment, growth and mortality was compared with among-site variability using Bayesian hierarchical modelling to determine the generality of each site's patterns and potential for meaningful comparisons among sites. The Malaysian forest, which experiences community-wide masting, was the most variable in both seedling density and recruitment. However, density varied year-to-year at all sites (CVamong years at site = 8–43%), driven largely by high variability in recruitment rates (CV = 40–117%). At all sites, recruitment was more variable than mortality (CV = 5–64%) or growth (CV = 12–51%). Increases in mortality rates lagged 1 y behind large recruitment events. Within-site spatial variation and inter-annual differences were greater than differences among site averages in all rates, emphasizing the value of long-term comparative studies when generalizing how spatial and temporal variation drive patterns of recruitment in tropical forests.

Sign in / Sign up

Export Citation Format

Share Document