Climate and landuse change enhance spatio-temporal variability of Dongjiang river flow and ammonia nitrogen

Jie Jiang; Zhaoli Wang; Chengguang Lai; Xushu Wu; Xiaohong Chen

doi:10.1016/j.scitotenv.2023.161483

Climate and landuse change enhance spatio-temporal variability of Dongjiang river flow and ammonia nitrogen

Sci Total Environ. 2023 Apr 1:867:161483. doi: 10.1016/j.scitotenv.2023.161483. Epub 2023 Jan 9.

Authors

Jie Jiang¹, Zhaoli Wang², Chengguang Lai¹, Xushu Wu³, Xiaohong Chen⁴

Affiliations

¹ School of Civil Engineering and Transportation, State Key Laboratory of Subtropical Building Science, South China University of Technology, Guangzhou 510641, China; Pazhou Lab, Guangzhou 510335, China.
² School of Civil Engineering and Transportation, State Key Laboratory of Subtropical Building Science, South China University of Technology, Guangzhou 510641, China; Pazhou Lab, Guangzhou 510335, China. Electronic address: wangzhl@scut.edu.cn.
³ School of Civil Engineering and Transportation, State Key Laboratory of Subtropical Building Science, South China University of Technology, Guangzhou 510641, China.
⁴ Center for Water Resource and Environment, Sun Yat-sen University, Guangzhou 510275, China.

PMID: 36634765
DOI: 10.1016/j.scitotenv.2023.161483

Abstract

The adverse impacts of climate and landuse change are threatening the availability of water quantity and its quality, yet there are limited understandings in the response of water availability to changing environment at different spatio-temporal scales. Aimed at quantifying the individual and superimposed effects of climate and landuse change on streamflow and ammonia nitrogen (NH₃-N) load in the Dongjiang River Basin (DRB), we dynamically simulated the historical (1981-2010) and future (2030-2070) variation of runoff depth and NH₃-N load coupling multiple regional climate model and landuse data. The increase in runoff depth (avg. +233.9 mm) due to climate change was about 33 times greater than that caused by landuse change (avg. -7.2 mm). Especially in the downstream of DRB (Hong Kong, Shenzhen and Dongguan cities, etc.), the maximum rise of runoff depth under climate change was near twice compared with baseline period, indicating the dominant control of climate change on runoff. Also there existed higher coefficient of variation (C_v) value of runoff in the dry season of downstream DRB, contributing potential great fluctuation in runoff. Besides, the variation of NH₃-N load was jointly influenced by climate and landuse change, revealing an offset or amplification effect. Moreover, the variability of NH₃-N load (C_v value as the metric) increased from 2030, reached a maximum in 2050, following decreased to 2070. The spatial distribution of NH₃-N load, in general, presented a downward trend and concentrated near the water body, while the monthly average NH₃-N load showed distinct peaks in spring and late summer temporally. Overall, the results highlight the significance of investigating the water availability under changing environment and more adaptive strategies should be proposed for better basin water management.

Keywords: Ammonia nitrogen; Climate change; Landuse change; Streamflow; Variability and contribution.