The impacts of climate variability and human activities on streamflow change at basin scale

2020 ◽  
Vol 20 (3) ◽  
pp. 889-899 ◽  
Author(s):  
Farshid Zolfagharpour ◽  
Bahram Saghafian ◽  
Majid Delavar

Abstract Human activities (HA) and/or climate variability (CV) may be two major factors impacting natural flow regime (NFR). This study was conducted following two objectives. The first was to develop scenario-based hydrological modeling (SBHM) to disentangle the natural and human-induced impacts on flow regime. The second objective was to quantify the interaction between temperature and precipitation for the assessment of CV. To do so, six scenarios were defined to evaluate either the impact of HA, CV or both. Four major results were achieved: (1) the interaction between temperature and precipitation was more prominent in basin upstream areas, which reduced the streamflow by 9% in the entire simulation period; (2) when separating the effects of climatic and human factors, SBHM results in comparison with those of the climate elasticity analysis showed no significant differences; (3) HA were the main force driving the streamflow reduction in the study basin; (4) a 5 °C increase in air temperature in the future would lead to an increase of 1.6% in average annual streamflow, and 41% in peak runoff.

2020 ◽  
Author(s):  
Marta Ferrazzi ◽  
Roberto Vivian ◽  
Gianluca Botter

<p>The simultaneous growth in climate-driven fluctuations of river flow regimes and global freshwater demand threatens the security of anthropogenic and ecologic uses of streamflows. Dams have long been designed to reconcile the conflict between patterns of human water uses and the temporal variability of flows, and are operated worldwide. In this context, there is a need to understand the combined influence of reservoir operations and climate variability on regulated streamflow regimes, and disclose whether observed hydroclimatic fluctuations can be accommodated by existing reservoirs. Here, these issues are addressed through a quantitative analysis of flow regime alterations by dams as driven by heterogeneous uses and variable regulation capacities (i.e., storage capacity scaled to the average inflow). In particular, the concept of streamflow stability is used to compare inter-annual changes in the occurrence probability of synchronous flows observed upstream and downstream of dams. The selection of structures considered in this study is distributed throughout the entire Central-Eastern United States, so as to span heterogeneous hydroclimatic settings and reservoir functions (i.e., flood control, water supply, hydropower production and multi-purpose). Our results reveal that reservoirs devoted to flood control and those operating for water supply produce distinctive impacts on flow regimes. Flood control does not alter the mean discharge downstream, but decreases long-term discharge variability and, thus, homogenize regional flow dynamics. However, regulation for flood control is unable to mitigate the impact of variable climate drivers on the stability of streamflows and hydroclimatic fluctuations typical of unregulated regimes are transferred unaltered in downstream reaches, or even amplified. Water supply, instead, reduces the mean flow of regulated reaches but increases the long-term streamflow variability, thereby enhancing the regional heterogeneity of flows. In this case, regulation smooths inter-annual changes of flow regimes, though at the cost of systematically filtering out medium-to-high discharges, with negative consequences on stream ecosystems. The observed connection between reservoir functions and the features of downstream flow regime alterations by dams represents a critical step forward for a sustainable management of water resources.</p>


2017 ◽  
Vol 49 (1) ◽  
pp. 177-193 ◽  
Author(s):  
Zharong Pan ◽  
Xiaohong Ruan ◽  
Mingkai Qian ◽  
Jian Hua ◽  
Nan Shan ◽  
...  

AbstractThe water shortage in the Huaihe River Basin (HRB), China, has been aggravated by population growth and climate change. To identify the characteristics of streamflow change and assess the impact of climate variability and human activities on hydrological processes, approximately 50 years of natural and observed streamflow data from 20 hydrological stations were examined. The Mann–Kendall test was employed to detect trends. The results showed the following. (i) Both the natural and the observed streamflow in the HRB present downward trends, and the decreasing rate of observed streamflow is generally faster than that of the natural streamflow. (ii) For the whole period, negative trends dominate in the four seasons in the basin. The highest decreasing trends for two kinds of streamflow both occurred in spring, and the lowest ones were in autumn and winter. (iii) Based on the above analysis and quantifying assessment for streamflow decrease, human activity was the main driving factor in the Xuanwu (80.78%), Zhuangqiao (79.92%), Yongcheng (74.80%), and Mengcheng (64.73%) stations which all belong to the Huaihe River System (HRS). On the other hand, climate variability was the major driving factor in the Daguanzhuang (68.89%) and Linyi (63.38%) stations which all belong to the Yishusi River System (YSR).


2017 ◽  
Vol 18 (11) ◽  
pp. 3027-3041 ◽  
Author(s):  
Melanie Raimonet ◽  
Ludovic Oudin ◽  
Vincent Thieu ◽  
Marie Silvestre ◽  
Robert Vautard ◽  
...  

Abstract The number and refinement of gridded meteorological datasets are on the rise at the global and regional scales. Although these datasets are now commonly used for hydrological modeling, the representation of precipitation amount and timing is crucial to correctly model streamflow. The Génie Rural à 4 paramètres journalier (GR4J) conceptual hydrological model combined with the CEMANEIGE snow routine was calibrated using four temperature and precipitation datasets [Système d’analyse fournissant des renseignements atmosphériques à la neige (SAFRAN), Mesoscale Analysis (MESAN), E-OBS, and Water and Global Change (WATCH) Forcing Data ERA-Interim (WFDEI)] on 931 French gauged catchments ranging in size from 10 to 10 000 km2. The efficiency of the calibrated hydrological model in simulating streamflow was higher for the models calibrated on high-resolution meteorological datasets (SAFRAN, MESAN) compared to coarse-resolution datasets (E-OBS, WFDEI), as well as for reanalysis (SAFRAN, MESAN, WFDEI) compared to datasets based on interpolation only (E-OBS). The systematic decrease in efficiency associated with precipitation bias or temporality highlights that the use of a hydrological model calibrated on meteorological datasets can assess these datasets, most particularly precipitation. It appears essential that datasets account for high-resolution topography to accurately represent elevation gradients and assimilate dense ground-based observation networks. This is particularly emphasized for hydrological applications in mountainous areas and areas subject to finescale events. For hydrological applications on nonmountainous regions, not subject to finescale events, both regional and global datasets give satisfactory results. It is crucial to continue improving precipitation datasets, especially in mountainous areas, and to assess their sensitivity to eventual corrupted observations. These datasets are essential to correct the bias of climate model outputs and to investigate the impact of climate change on hydrological regimes.


2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Sidong Zeng ◽  
Chesheng Zhan ◽  
Fubao Sun ◽  
Hong Du ◽  
Feiyu Wang

Quantifying the effects of climate change and human activities on runoff changes is the focus of climate change and hydrological research. This paper presents an integrated method employing the Budyko-based Fu model, hydrological modeling, and climate elasticity approaches to separate the effects of the two driving factors on surface runoff in the Luan River basin, China. The Budyko-based Fu model and the double mass curve method are used to analyze runoff changes during the period 1958~2009. Then two types of hydrological models (the distributed Soil and Water Assessment Tool model and the lumped SIMHYD model) and seven climate elasticity methods (including a nonparametric method and six Budyko-based methods) are applied to estimate the contributions of climate change and human activities to runoff change. The results show that all quantification methods are effective, and the results obtained by the nine methods are generally consistent. During the study period, the effects of climate change on runoff change accounted for 28.3~46.8% while those of human activities contributed with 53.2~71.7%, indicating that both factors have significant effects on the runoff decline in the basin, and that the effects of human activities are relatively stronger than those of climate change.


2007 ◽  
Vol 21 (25) ◽  
pp. 3485-3491 ◽  
Author(s):  
Li-Juan Li ◽  
Lu Zhang ◽  
Hao Wang ◽  
Juan Wang ◽  
Jun-Wei Yang ◽  
...  

1999 ◽  
Vol 31 (3) ◽  
pp. 537-549 ◽  
Author(s):  
Bruce L. Dixon ◽  
Kathleen Segerson

AbstractApproximate profit functions are estimated using time-series, cross-sectional, county level data for 12 midwest states. Measures of climate variability are included in the profit functions. Simulated impacts of climate changes on profits are derived. Results show that inclusion of measures of climate variation are important for measuring the impact of changes in mean temperature and precipitation levels. Failure to account for the impact of differences in variability leads to an overestimate of damages. If global warming increases diurnal variation, such increases would have negative impacts on the profitability of midwest agriculture.


2016 ◽  
Vol 20 (4) ◽  
pp. 1547-1560 ◽  
Author(s):  
Jianxia Chang ◽  
Hongxue Zhang ◽  
Yimin Wang ◽  
Yuelu Zhu

Abstract. Water resources in river systems have been changing under the impact of both climate variability and human activities. Assessing the respective impact on decadal streamflow variation is important for water resource management. By using an elasticity-based method and calibrated TOPMODEL and VIC hydrological models, we quantitatively isolated the relative contributions that human activities and climate variability made to decadal streamflow changes in the Jinghe basin, located in the northwest of China. This is an important watershed of the Shaanxi province that supplies drinking water for a population of over 6 million people. The results showed that the maximum value of the moisture index (E0∕P) was 1.91 and appeared in 1991–2000, and the decreased speed of streamflow was higher since 1990 compared with 1960–1990. The average annual streamflow from 1990 to 2010 was reduced by 26.96 % compared with the multiyear average value (from 1960 to 2010). The estimates of the impacts of climate variability and human activities on streamflow decreases from the hydrological models were similar to those from the elasticity-based method. The maximum contribution value of human activities was 99 % when averaged over the three methods, and appeared in 1981–1990 due to the effects of soil and water conservation measures and irrigation water withdrawal. Climate variability made the greatest contribution to streamflow reduction in 1991–2000, the values of which was 40.4 %. We emphasized various source of errors and uncertainties that may occur in the hydrological model (parameter and structural uncertainty) and elasticity-based method (model parameter) in climate change impact studies.


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