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Wu Y, Su H, Cheng L, Qin S, Zou K, Liu Y, Zhou J, Liu P, Zhang L. Exploring hydrological controls on dissolved organic carbon export dynamics in a typical flash flood catchment using a process-based model. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 921:171139. [PMID: 38402981 DOI: 10.1016/j.scitotenv.2024.171139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 01/17/2024] [Accepted: 02/19/2024] [Indexed: 02/27/2024]
Abstract
The dynamics of dissolved organic carbon (DOC) export from headwater catchments are of critical importance for the global carbon balance and are driven by complex runoff processes. Most previous studies have used statistical relationships between runoff and DOC concentration to estimate DOC export dynamics. Thus, the coupling mechanisms between runoff generation and DOC export dynamics at the process level were obscured in the fitting parameters and have rarely been addressed. In this study, high-frequency (hourly) discharge and DOC export from a typical flash flood experimental headwater catchment with an area of 1.8 km2 were simulated using a process-based model (INCA-C). The results showed that the INCA-C model successfully captured the hourly dynamics of both discharge and DOC concentrations with a Nash-Sutcliffe efficiency (NSE) of 0.47-0.81 and 0.28-0.70 among moderate events and 0.81-0.85 and 0.19-0.90 among extreme events, respectively. The DOC was exported with distinct concentration dynamics, fluxes, and contributions from the four flow pathways under different storm intensities. At higher intensities, the DOC fluxes were exported by subsurface flows, particularly from shallow organic soil, with greater peaks and shorter time-to-peaks. Exported DOC is primarily sourced from subsurface runoff from the mineral layer (73 %-77 %) during moderate events, whereas it is primarily sourced from subsurface runoff from the organic layer (61 %-79 %) during extreme events. The two contrasting contributions suggest that hydrological pathway controls and DOC dynamic patterns can shift owing to runoff generation influenced by storm intensity. The distinct and variable controls of different flow pathways on DOC export highlight the need to explain the role of hydrology in regulating DOC storm exports through process-based modelling.
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Affiliation(s)
- Yue Wu
- State Key Laboratory of Water Resources Engineering and Management, Wuhan University, Wuhan 430072, China; Hubei Provincial Collaborative Innovation Centre for Water Resources Security, Wuhan 430072, China
| | - Hang Su
- State Key Laboratory of Water Resources Engineering and Management, Wuhan University, Wuhan 430072, China; Hubei Provincial Collaborative Innovation Centre for Water Resources Security, Wuhan 430072, China
| | - Lei Cheng
- State Key Laboratory of Water Resources Engineering and Management, Wuhan University, Wuhan 430072, China; Hubei Provincial Collaborative Innovation Centre for Water Resources Security, Wuhan 430072, China.
| | - Shujing Qin
- State Key Laboratory of Water Resources Engineering and Management, Wuhan University, Wuhan 430072, China; Hubei Provincial Collaborative Innovation Centre for Water Resources Security, Wuhan 430072, China
| | - Kaijie Zou
- State Key Laboratory of Water Resources Engineering and Management, Wuhan University, Wuhan 430072, China; Hubei Provincial Collaborative Innovation Centre for Water Resources Security, Wuhan 430072, China
| | - Yanghe Liu
- China Yangtze Power Co., Ltd., Yichang 443133, China; Hubei Key Laboratory of Intelligent Yangtze and Hydroelectric Science, Yichang 443133, China
| | - Jingzhe Zhou
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China
| | - Pan Liu
- State Key Laboratory of Water Resources Engineering and Management, Wuhan University, Wuhan 430072, China; Hubei Provincial Collaborative Innovation Centre for Water Resources Security, Wuhan 430072, China
| | - Lu Zhang
- State Key Laboratory of Water Resources Engineering and Management, Wuhan University, Wuhan 430072, China; Hubei Provincial Collaborative Innovation Centre for Water Resources Security, Wuhan 430072, China
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Yang S, Liang M, Qin Z, Qian Y, Li M, Cao Y. A novel assessment considering spatial and temporal variations of water quality to identify pollution sources in urban rivers. Sci Rep 2021; 11:8714. [PMID: 33888742 PMCID: PMC8062557 DOI: 10.1038/s41598-021-87671-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 03/24/2021] [Indexed: 11/16/2022] Open
Abstract
It’s vital to explore critical indicators when identifying potential pollution sources of urban rivers. However, the variations of urban river water qualities following temporal and spatial disturbances were highly local-dependent, further complicating the understanding of pollution emission laws. In order to understand the successional trajectory of water qualities of urban rivers and the underlying mechanisms controlling these dynamics at local scale, we collected daily monitoring data for 17 physical and chemical parameters from seven on-line monitoring stations in Nanfeihe River, Anhui, China, during the year 2018. The water quality at tributaries were similar, while that at main river was much different. A seasonal ‘’turning-back” pattern was observed in the water quality, which changed significantly from spring to summer but finally changed back in winter. This result was possibly regulated by seasonally-changed dissolved oxygen and water temperature. Linear mixed models showed that the site 2, with the highest loads of pollution, contributed the highest (β = 0.316, P < 0.001) to the main river City Water Quality Index (CWQI) index, but site 5, the geographically nearest site to main river monitoring station, did not show significant effect. In contrast, site 5 but not site 2 contributed the highest (β = 0.379, P < 0.001) to the main river water quality. Therefore, CWQI index was a better index than water quality to identify potential pollution sources with heavy loads of pollutants, despite temporal and spatial disturbances at local scales. These results highlight the role of aeration in water quality controlling of urban rivers, and emphasized the necessity to select proper index to accurately trace the latent pollution sources.
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Affiliation(s)
- Sihang Yang
- Institute of Public Safety Research, Department of Engineering Physics, Beijing Key Laboratory of City Integrated Emergency Response Science, Tsinghua University, Beijing, China
| | - Manchun Liang
- Institute of Public Safety Research, Department of Engineering Physics, Beijing Key Laboratory of City Integrated Emergency Response Science, Tsinghua University, Beijing, China.
| | - Zesheng Qin
- Environmental Safety Business Division, Beijing GSafety Technology, Co., Ltd., Beijing, China
| | - Yiwu Qian
- Hefei Institute for Public Safety Research, Tsinghua University, Hefei, China
| | - Mei Li
- Hefei Institute for Public Safety Research, Tsinghua University, Hefei, China
| | - Yi Cao
- Hefei Institute for Public Safety Research, Tsinghua University, Hefei, China
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Jacobs SR, Weeser B, Rufino MC, Breuer L. Diurnal Patterns in Solute Concentrations Measured with In Situ UV-Vis Sensors: Natural Fluctuations or Artefacts? SENSORS 2020; 20:s20030859. [PMID: 32041157 PMCID: PMC7039225 DOI: 10.3390/s20030859] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Revised: 01/28/2020] [Accepted: 02/03/2020] [Indexed: 11/16/2022]
Abstract
In situ spectrophotometers measuring in the UV-visible spectrum are increasingly used to collect high-resolution data on stream water quality. This provides the opportunity to investigate short-term solute dynamics, including diurnal cycling. This study reports unusual changes in diurnal patterns observed when such sensors were deployed in four tropical headwater streams in Kenya. The analysis of a 5-year dataset revealed sensor-specific diurnal patterns in nitrate and dissolved organic carbon concentrations and different patterns measured by different sensors when installed at the same site. To verify these patterns, a second mobile sensor was installed at three sites for more than 3 weeks. Agreement between the measurements performed by these sensors was higher for dissolved organic carbon (r > 0.98) than for nitrate (r = 0.43–0.81) at all sites. Higher concentrations and larger amplitudes generally led to higher agreement between patterns measured by the two sensors. However, changing the position or level of shading of the mobile sensor resulted in inconsistent changes in the patterns. The results of this study show that diurnal patterns measured with UV-Vis spectrophotometers should be interpreted with caution. Further work is required to understand how these measurements are influenced by environmental conditions and sensor-specific properties.
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Affiliation(s)
- Suzanne R. Jacobs
- Center for international Development and Environmental Research (ZEU), Justus Liebig University, Senckenbergstr. 3, 35390 Giessen, Germany; (B.W.); (L.B.)
- Institute for Landscape Ecology and Resources Management (ILR), Justus Liebig University, Heinrich-Buff-Ring 26, 35392 Giessen, Germany
- Correspondence:
| | - Björn Weeser
- Center for international Development and Environmental Research (ZEU), Justus Liebig University, Senckenbergstr. 3, 35390 Giessen, Germany; (B.W.); (L.B.)
- Institute for Landscape Ecology and Resources Management (ILR), Justus Liebig University, Heinrich-Buff-Ring 26, 35392 Giessen, Germany
| | - Mariana C. Rufino
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK;
- Centre for International Forestry Research (CIFOR), c/o World Agroforestry Centre, United Nations Avenue, Gigiri, 00100 Nairobi, Kenya
| | - Lutz Breuer
- Center for international Development and Environmental Research (ZEU), Justus Liebig University, Senckenbergstr. 3, 35390 Giessen, Germany; (B.W.); (L.B.)
- Institute for Landscape Ecology and Resources Management (ILR), Justus Liebig University, Heinrich-Buff-Ring 26, 35392 Giessen, Germany
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Rotteveel L, Sterling SM. Five Aluminum Seasonality Regimes Identified in Chronically Acidified Rivers of Nova Scotia. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:807-817. [PMID: 31856567 DOI: 10.1021/acs.est.9b04872] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Despite reductions in acidic deposition, high freshwater Al concentrations continue to threaten acidified ecosystems across the northern hemisphere. Seasonally elevated Al concentrations may pose a particular threat to freshwater organisms. Despite this threat, there is a lack of understanding about the timing and drivers of seasonal Al fluctuations. Here, we address this knowledge gap by identifying seasonal patterns of Al and their drivers in 16 rivers across Nova Scotia, Canada. We identify five distinct Al regimes with different timing of seasonally elevated Al concentrations. Regimes are distinguished by correlation strength and direction between Al and base cations, total organic carbon, turbidity, and discharge. Most notably, regimes are distinguished by a gradient of Al-base cation decoupling as Ca and Mg concentration approaches 1.4 mg L-1 and 0.6 mg L-1, respectively. Seasonally elevated Al concentrations exceeded the 0.1-0.2 mg L-1 World Health Organization drinking water guidelines in all regimes, and inorganic monomeric Al is projected to exceed the 15 μg L-1 threshold for aquatic health in most rivers. This research highlights the complexity of seasonal Al dynamics and the importance of understanding seasonal variation of Al to quantify the impact of Al on human health, water treatment, and aquatic organisms.
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Affiliation(s)
- Lobke Rotteveel
- Sterling Hydrology Research Group, Department of Earth Sciences , Dalhousie University , Halifax B3H 4J1 , Canada
| | - Shannon M Sterling
- Sterling Hydrology Research Group, Department of Earth Sciences , Dalhousie University , Halifax B3H 4J1 , Canada
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Innovations in Monitoring With Water-Quality Sensors With Case Studies on Floods, Hurricanes, and Harmful Algal Blooms. SEP SCI TECHNOL 2019. [DOI: 10.1016/b978-0-12-815730-5.00010-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Ruhala SS, Zarnetske JP. Using in-situ optical sensors to study dissolved organic carbon dynamics of streams and watersheds: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 575:713-723. [PMID: 27678048 DOI: 10.1016/j.scitotenv.2016.09.113] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 09/14/2016] [Accepted: 09/14/2016] [Indexed: 05/21/2023]
Abstract
It is important to understand how dissolved organic carbon (DOC) is processed and transported through stream networks because DOC is a master water quality variable in aquatic ecosystems. High-frequency sampling is necessary to capture important, rapid shifts in DOC source, concentration, and composition (i.e. quality) in streams. Until recently, this high-frequency sampling was logistically difficult or impossible. However, this type of sampling can now be conducted using in-situ optical measurements through long-term, field-deployable fluorometers and spectrophotometers. The optical data collected from these instruments can quantify both DOC concentration and composition properties (e.g., specific ultra-violet absorbance at 254nm, spectral slope ratio, and fluorescence index). Previously, the use of these sensors was limited to a small number of specialized users, mainly in Europe and North America, where they were used predominantly in marine DOC studies as well as water treatment and management infrastructure. However, recent field demonstrations across a wide range of river systems reveals a large potential for the use of these instruments in freshwater environments, heightening interest and demand across multiple environmental research and management disciplines. Hence, this review provides an up-to-date synthesis on 1) the use of spectroscopy as a diagnostic tool in stream DOC studies, 2) the instrumentation, its applications, potential limitations and future considerations, and 3) the new watershed DOC research directions made possible via these in-situ optical sensors.
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Affiliation(s)
- Sydney S Ruhala
- Department of Earth and Environmental Sciences, Michigan State University, East Lansing, MI, USA.
| | - Jay P Zarnetske
- Department of Earth and Environmental Sciences, Michigan State University, East Lansing, MI, USA.
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Blaen PJ, Khamis K, Lloyd CEM, Bradley C, Hannah D, Krause S. Real-time monitoring of nutrients and dissolved organic matter in rivers: Capturing event dynamics, technological opportunities and future directions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 569-570:647-660. [PMID: 27376920 DOI: 10.1016/j.scitotenv.2016.06.116] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 06/15/2016] [Accepted: 06/15/2016] [Indexed: 05/28/2023]
Abstract
Excessive riverine nutrient concentrations threaten aquatic ecosystem structure and functioning and can pose substantial risks to human health. Robust monitoring strategies are therefore required to generate reliable estimates of river nutrient loads and to improve understanding of the catchment processes that drive nutrient fluxes. Furthermore, these data are vital for prediction of future trends under changing environmental conditions and thus the development of appropriate mitigation measures. In recent years, technological developments have led to an increase in the use of in-situ nutrient analysers, which enable measurements at far higher temporal resolutions than can be achieved with discrete sampling and subsequent laboratory analysis. In this paper, we review the principles underlying the key techniques used for in-situ nutrient monitoring and highlight both the advantages, opportunities and challenges associated with high-resolution sampling programs. We then suggest how adaptive monitoring strategies, comprising several different temporal sample frequencies, controlled by one or more 'trigger variables' (e.g. river stage, turbidity, or nutrient concentration), can advance our understanding of catchment nutrient dynamics while simultaneously overcoming many of the practical and economic challenges encountered in typical in-situ river nutrient monitoring applications. We present examples of short-term variability in river nutrient dynamics, driven by complex catchment behaviour, which support our case for the development of monitoring systems that can adapt in real-time to rapid changes in environmental conditions. Finally, we suggest future research directions based on emerging technologies in this field.
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Affiliation(s)
- Phillip J Blaen
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK; Birmingham Institute of Forest Research (BIFoR), University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
| | - Kieran Khamis
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Charlotte E M Lloyd
- Organic Geochemistry Unit, Bristol Biogeochemistry Research Centre, School of Chemistry, University of Bristol, Cantocks Close, Bristol BS8 1TS, UK
| | - Chris Bradley
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - David Hannah
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Stefan Krause
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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