scholarly journals The Water Quality of the River Enborne, UK: Observations from High-Frequency Monitoring in a Rural, Lowland River System

Water ◽  
2014 ◽  
Vol 6 (1) ◽  
pp. 150-180 ◽  
Author(s):  
Sarah Halliday ◽  
Richard Skeffington ◽  
Michael Bowes ◽  
Emma Gozzard ◽  
Jonathan Newman ◽  
...  
2016 ◽  
Vol 19 (2) ◽  
pp. 107-117
Author(s):  
Trang Thi Thuy Nguyen ◽  
Khoi Nguyen Dao

The objective of this study was to simulate the hydrologic characteristic and water quality of 3S rivers system (Sekong, Sesan and Srepok) using SWAT model (Soil and Water Analysis Tool). Agriculture and forest are the main land use types in this basin accounting for more than 80 % of the total area. Therfore, nitrogen and phosphorus were selected to be parameters for water quality assessment. SWAT-CUP model was applied to calibrate the model for stream flow and water quality based on SUFI-2 (Sequential Uncertainty Fitting version 2) method. The model performance has been assessed by three statistical indices, including coefficient corellation (R2), Nash-Sutcliffe efficient coefficience (NSE) and percentage Bias (PBIAS). The results showed that SWAT model was well calibrated for simulating the streamflow and water quality with the values of R2 greater than 0.5 except for the Attapeu and Kontum stations, and of PBIAS less than 10 % and 35 % for streamflow and water quality, respectively. The well-calibrated SWAT model can be applied in predicting the hydrology and water quality for other application. Furthermore, it is a tool supporting the policy makers to offer a suitable decisions regarding the sustainable river basin management.


2018 ◽  
Vol 564 ◽  
pp. 619-639 ◽  
Author(s):  
M. Kämäri ◽  
S. Tattari ◽  
E. Lotsari ◽  
J. Koskiaho ◽  
C.E.M. Lloyd

2016 ◽  
Vol 20 (5) ◽  
pp. 1851-1868 ◽  
Author(s):  
Bas van der Grift ◽  
Hans Peter Broers ◽  
Wilbert Berendrecht ◽  
Joachim Rozemeijer ◽  
Leonard Osté ◽  
...  

Abstract. Many agriculture-dominated lowland water systems worldwide suffer from eutrophication caused by high nutrient loads. Insight in the hydrochemical functioning of embanked polder catchments is highly relevant for improving the water quality in such areas or for reducing export loads to downstream water bodies. This paper introduces new insights in nutrient sources and transport processes in a polder in the Netherlands situated below sea level using high-frequency monitoring technology at the outlet, where the water is pumped into a higher situated lake, combined with a low-frequency water quality monitoring programme at six locations within the drainage area. Seasonal trends and short-scale temporal dynamics in concentrations indicated that the NO3 concentration at the pumping station originated from N loss from agricultural lands. The NO3 loads appear as losses via tube drains after intensive rainfall events during the winter months due to preferential flow through the cracked clay soil. Transfer function-noise modelling of hourly NO3 concentrations reveals that a large part of the dynamics in NO3 concentrations during the winter months can be related to rainfall. The total phosphorus (TP) concentration and turbidity almost doubled during operation of the pumping station, which points to resuspension of particulate P from channel bed sediments induced by changes in water flow due to pumping. Rainfall events that caused peaks in NO3 concentrations did not results in TP concentration peaks. The rainfall induced and NO3 enriched quick interflow, may also be enriched in TP but retention of TP due to sedimentation of particulate P then results in the absence of rainfall induced TP concentration peaks. Increased TP concentrations associated with run-off events is only observed during a rainfall event at the end of a freeze–thaw cycle. All these observations suggest that the P retention potential of polder water systems is primarily due to the artificial pumping regime that buffers high flows. As the TP concentration is affected by operation of the pumping station, timing of sampling relative to the operating hours of the pumping station should be accounted for when calculating P export loads, determining trends in water quality, or when judging water quality status of polder water systems.


2019 ◽  
Vol 104 ◽  
pp. 13-23 ◽  
Author(s):  
Paula El Najjar ◽  
Amine Kassouf ◽  
Anne Probst ◽  
Jean-Luc Probst ◽  
Naim Ouaini ◽  
...  

RBRH ◽  
2016 ◽  
Vol 21 (4) ◽  
pp. 653-665
Author(s):  
Rubia Girardi ◽  
Adilson Pinheiro ◽  
Edson Torres ◽  
Vander Kaufmann ◽  
Luis Hamilton Pospissil Garbossa

ABSTRACT Studies carried out over short time intervals assist in understanding the biogeochemical processes occurring relatively fast in natural waters. High frequency monitoring shows a greater variability in the water quality during and immediately after heavy rainfall events. This paper presents an assessment of the surface water quality parameters in the Atlantic Forest biome, caused by heavy rainfall events. The work was developed in two fluviometric sections of the Concordia River watershed, located in the state of Santa Catarina, southern Brazil. The spatial distribution of land use shows the predominance of Atlantic Forest in fluviometric section 1 (FS1) and pasture, forestry, agriculture, and Atlantic Forest in fluviometric section 2 (FS2). In each selected heavy rainfall event, the evolution rainfall height, the water level, and physicochemical parameters of water were analyzed. In all events, the water quality changed due to the heavy rainfall. After the events, an increase in water level and turbidity in both fluviometric sections were detected. In addition, the ammonium ion concentration increased in the river, and the pH value and nitrate concentration decreased. The electrical conductivity presented different behavior in each section. The dissolved oxygen concentration increased in 19 of 27 events. The principal component (PC1) correlated with the turbidity in FS1, and it correlated with level, turbidity, and pH in FS2.


2015 ◽  
Vol 12 (8) ◽  
pp. 8337-8380 ◽  
Author(s):  
B. van der Grift ◽  
H. P. Broers ◽  
W. L. Berendrecht ◽  
J. C. Rozemeijer ◽  
L. A. Osté ◽  
...  

Abstract. Many agriculture-dominated lowland water systems worldwide suffer from eutrophication caused by high nutrient loads. Insight in the hydrochemical functioning of embanked polder catchments is highly relevant for improving the water quality in such areas. This paper introduces new insights in nutrient sources and transport processes in a low elevated polder in the Netherlands using high-frequency monitoring technology at the outlet, where the water is pumped into a higher situated lake, combined with a low-frequency water quality monitoring program at six locations within the drainage area. Seasonal trends and short scale temporal dynamics in concentrations indicated that the NO3 concentration at the pumping station originated from N-loss from agricultural lands. The NO3 loads appear as losses with drain water discharge after intensive rainfall events during the winter months due to preferential flow through the cracked clay soil. Transfer function-noise modelling of hourly NO3 concentrations reveals that a large part of the dynamics in NO3 concentrations during the winter months can be related to rainfall. The total phosphorus (TP) concentration almost doubled during operation of the pumping station which points to resuspension of particulate P from channel bed sediments induced by changes in water flow due to pumping. Rainfall events that caused peaks in NO3 concentrations did not results in TP concentration peaks. The by rainfall induced and NO3 enriched quick interflow, may also be enriched in TP but this is then buffered in the water system due to sedimentation of particulate P. Increased TP concentrations associated with run-off events is only observed during a rainfall event at the end of a freeze–thaw cycle. All these observations suggest that the P retention potential of polder water systems is highly due to the artificial pumping regime that buffers high flows. As the TP concentration is affected by operation of the pumping station, timing of sampling relative to the operating hours of the pumping station should be accounted for when calculating P export loads, determining trends in water quality or when judging water quality status of polder water systems.


2020 ◽  
Author(s):  
Liang Yu ◽  
Joachim C. Rozemeijer ◽  
Hans Peter Broers ◽  
Boris M. van Breukelen ◽  
Jack J. Middelburg ◽  
...  

Abstract. Eutrophication of water bodies has been a problem causing severe degradation of water quality in cities. To gain mechanistic understanding of the temporal dynamics of nitrogen and phosphorus in a groundwater fed low-lying urban polder, we applied high frequency monitoring in Geuzenveld, a polder in the city of Amsterdam. The high frequency monitoring equipment was installed at the pumping station where water leaves the polder. From 2016 March to 2017 June, total phosphorus (TP), ammonium (NH4), turbidity, electrical conductivity (EC), and water temperature were measured at intervals smaller than 20 minutes. This paper discusses the results at three time scales: annual scale, rain event scale, and single pumping event scale. Mixing of upwelling groundwater and runoff was the dominant hydrological process and governed the temporal pattern of the EC, while N and P fluxes from the polder were also significantly regulated by primary production and iron transformations. The mixing of groundwater and runoff water governed water quality through variation of the intensity and duration of the events. For NH4, the dominant form of N in surface water originating from groundwater seepage, we observed low concentrations during the algae growing season, while concentrations were governed by mixing of groundwater and precipitation inputs in the late autumn and winter. The depletion of dissolved NH4 in spring suggests uptake by primary producers, consistent with high chlorophyll-a, O2, and suspended solids during this period. Total P and turbidity were high during winter, due to the release of reduced iron and P from anoxic sediment to the water column. Rapid Fe2+ oxidation in the water column is the major cause of turbidity. In the other seasons, P is retained in the sediment by iron oxides. Nitrogen is exported from the polder to the downstream water bodies throughout the whole year, mostly in the form of NH4, but as organic N in spring. P leaves the polder mainly during winter, primarily associated with Fe(OH)3 colloids and as dissolved P. Based on this new understanding of the dynamics of N and P in this low lying urban catchment, it is possible to formulate management strategies that can effectively control and reduce eutrophication situation in urban polders and receiving downstream waters.


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