Dynamics of dissolved organic carbon during drought and flood events: A phase-by-stages perspective

Jiefeng Wu; Huaxia Yao; Xiaohong Chen; Xingwei Chen

doi:10.1016/j.scitotenv.2023.162158

Dynamics of dissolved organic carbon during drought and flood events: A phase-by-stages perspective

Sci Total Environ. 2023 May 1:871:162158. doi: 10.1016/j.scitotenv.2023.162158. Epub 2023 Feb 10.

Authors

Jiefeng Wu¹, Huaxia Yao², Xiaohong Chen³, Xingwei Chen⁴

Affiliations

¹ Key Laboratory of Hydrometeorological Disaster Mechanism and Warning of Ministry of Water Resources, Nanjing University of Information Science and Technology, Nanjing, China; School of Hydrology and Water Resources, Nanjing University of Information Science and Technology, Nanjing, China. Electronic address: wujf27@nuist.edu.cn.
² Inland Water Unit, Environmental Monitoring and Reporting Branch, Ontario Ministry of Environment, Conservation and Parks, Dorset, Ontario, Canada.
³ Center for Water Resources and Environment, Sun Yat-sen University, Guangzhou, China.
⁴ College of Geographic Sciences, Fujian Normal University, Fuzhou, Fujian 350007, China.

PMID: 36773914
DOI: 10.1016/j.scitotenv.2023.162158

Abstract

Dissolved organic carbon (DOC) is a key water quality parameter that plays a crucial role in controlling aquatic ecosystems and carbon cycling. Understanding DOC dynamics during hydrological extremes (i.e., droughts and floods) helps in managing water quality, but such variability is rarely studied. Furthermore, how differences in DOC concentrations among phase-by-stages of drought/flood affect simulation performances based on hydrological features remains unclear. Here, phase-by-stages of hydrological drought (flood) were divided into intensification (rising) and recovery (falling) periods based on drought peak intensity (flood peak intensity). The long-term (1976-2019) daily discharge and weekly (biweekly) DOC concentrations from four headwater streams with different watershed sizes (from 9.97 to 119.09 ha) in south-central Ontario, Canada, were used to achieve the above aims. The results showed that (i) the average DOC concentration during intensification (rising) stage of drought (flood) was smaller (larger) than during recovery (falling). (ii) Simulations performed better when accounting for phase-by-stages of drought/flood, with reductions in mean absolute percentage error of 32.85 % and 53.59 % for drought and flood events, respectively. These results will help understand the dynamics of DOC during hydrological extremes and improve simulation performance of numerical models for water quality parameters under changing environmental conditions.

Keywords: DOC; Drought/flood events; Harp Lake; Hydrological extremes; Simulating.