scholarly journals Modelling the Impact of Vegetation Change on Hydrological Processes in Bayin River Basin, Northwest China

Water ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 2787
Author(s):  
Xin Jin ◽  
Yanxiang Jin ◽  
Xufeng Mao ◽  
Jingya Zhai ◽  
Di Fu
Keyword(s):  
Water Resources ◽  
River Basin ◽  
Vegetation Change ◽  
Northwest China ◽  
Hydrological Processes ◽  
Area Index ◽  
Groundwater Exchange ◽  
Low Coverage ◽  
The Impact ◽  
Regional Water

Vegetation change in arid areas may lead to the redistribution of regional water resources, which can intensify the competition between ecosystems and humans for water resources. This study aimed to accurately model the impact of vegetation change on hydrological processes in an arid endorheic river watershed undergoing revegetation, namely, the middle and lower reaches of the Bayin River basin, China. A LU-SWAT-MODFLOW model was developed by integrating dynamic hydrological response units with a coupled SWAT-MODFLOW model, which can reflect actual land cover changes in the basin. The LU-SWAT-MODFLOW model outperformed the original SWAT-MODFLOW model in simulating the impact of human activity as well as the leaf area index, evapotranspiration, and groundwater table depth. After regional revegetation, evapotranspiration and groundwater recharge in different sub-basins increased significantly. In addition, the direction and amount of surface-water–groundwater exchange changed considerably in areas where revegetation involved converting low-coverage grassland and bare land to forestland.

scholarly journals Coupling of dynamic hydrological response units and SWAT-MODFLOW to model the impact of vegetation change on hydrological processes in an arid endorheic river watershed

2021 ◽  
Author(s):  
Xin Jin ◽  
Yanxiang Jin
Keyword(s):  
Surface Water ◽  
Water Resources ◽  
Groundwater Recharge ◽  
Vegetation Change ◽  
Hydrological Processes ◽  
Arid Areas ◽  
Hydrological Response ◽  
River Watershed ◽  
Groundwater Exchange ◽  
The Impact

Abstract Vegetation change in arid areas may lead to the redistribution of regional water resources, which can intensify the competition between ecosystems and humans for water resources. Thus, it is necessary to understand the impact of vegetation change on hydrological processes in arid areas. We aimed to accurately model the impact of vegetation change on hydrological processes in an arid endorheic river watershed undergoing revegetation. The middle and lower reaches of the Bayin River basin, China were investigated because this is an area of frequent surface water–groundwater interactions and evident revegetation. A LU-SWAT-MODFLOW model was developed by integrating dynamic hydrological response units with a coupled SWAT-MODFLOW model, which can reflect actual land cover changes in the basin. The results showed that the LU-SWAT-MODFLOW model outperformed the original SWAT-MODFLOW model in simulating human activity impact as well as the leaf area index, evapotranspiration, and groundwater table depth. After regional revegetation, evapotranspiration in different sub-basins increased by 1.5 mm per month and by 6 mm per year. The groundwater recharge increased by 1.27 mm on average per month and 14.02 mm on average per year. Irrigation for the recovered vegetation strongly affected the groundwater recharge. In addition, the direction and amount of surface water–groundwater exchange considerably changed in areas where revegetation involved converting low-coverage grassland and bare land to forestland. In areas where revegetation involved converting farmland to forestland, the transition had a weak effect on the direction and amount of surface water–groundwater exchange.

scholarly journals Vegetation Dynamic Assessment by NDVI and Field Observations for Sustainability of China’s Wulagai River Basin

2021 ◽  
Vol 18 (5) ◽  
pp. 2528
Author(s):  
Panpan Chen ◽  
Huamin Liu ◽  
Zongming Wang ◽  
Dehua Mao ◽  
Cunzhu Liang ◽  
...  
Keyword(s):  
Species Diversity ◽  
River Basin ◽  
Vegetation Change ◽  
Vegetation Index ◽  
Dynamic Assessment ◽  
Indicator System ◽  
Vegetation Changes ◽  
Vegetation Dynamic ◽  
Management Policies ◽  
The Impact

Accurate monitoring of grassland vegetation dynamics is essential for ecosystem restoration and the implementation of integrated management policies. A lack of information on vegetation changes in the Wulagai River Basin restricts regional development. Therefore, in this study, we integrated remote sensing, meteorological, and field plant community survey data in order to characterize vegetation and ecosystem changes from 1997 to 2018. The residual trend (RESTREND) method was utilized to detect vegetation changes caused by human factors, as well as to evaluate the impact of the management of pastures. Our results reveal that the normalized difference vegetation index (NDVI) of each examined ecosystem type showed an increasing trend, in which anthropogenic impact was the primary driving force of vegetation change. Our field survey confirmed that the meadow steppe ecosystem increased in species diversity and aboveground biomass; however, the typical steppe and riparian wet meadow ecosystems experienced species diversity and biomass degradation, therefore suggesting that an increase in NDVI may not directly reflect ecosystem improvement. Selecting an optimal indicator or indicator system is necessary in order to formulate reasonable grassland management policies for increasing the sustainability of grassland ecosystems.

scholarly journals Attribution of Long-Term Evapotranspiration Trends in the Mekong River Basin with a Remote Sensing-Based Process Model

2021 ◽  
Vol 13 (2) ◽  
pp. 303
Author(s):  
Shi Hu ◽  
Xingguo Mo
Keyword(s):  
Remote Sensing ◽  
Water Resources ◽  
Solar Radiation ◽  
River Basin ◽  
Mekong Delta ◽  
Mekong River ◽  
Catchment Management ◽  
Mekong River Basin ◽  
Area Index ◽  
Available Water

Using the Global Land Surface Satellite (GLASS) leaf area index (LAI), the actual evapotranspiration (ETa) and available water resources in the Mekong River Basin were estimated with the Remote Sensing-Based Vegetation Interface Processes Model (VIP-RS). The relative contributions of climate variables and vegetation greening to ETa were estimated with numerical experiments. The results show that the average ETa in the entire basin increased at a rate of 1.16 mm year−2 from 1980 to 2012 (36.7% of the area met the 95% significance level). Vegetation greening contributed 54.1% of the annual ETa trend, slightly higher than that of climate change. The contributions of air temperature, precipitation and the LAI were positive, whereas contributions of solar radiation and vapor pressure were negative. The effects of water supply and energy availability were equivalent on the variation of ETa throughout most of the basin, except the upper reach and downstream Mekong Delta. In the upper reach, climate warming played a critical role in the ETa variability, while the warming effect was offset by reduced solar radiation in the Mekong Delta (an energy-limited region). For the entire basin, the available water resources showed an increasing trend due to intensified precipitation; however, in downstream areas, additional pressure on available water resources is exerted due to cropland expansion with enhanced agricultural water consumption. The results provide scientific basis for practices of integrated catchment management and water resources allocation.

Runoff Forecast and Analysis of the Probability of Dry and Wet Transition in the Hanjiang River Basin

2021 ◽  
Author(s):  
Haoyu Jin ◽  
Xiaohong Chen ◽  
Ruida Zhong
Keyword(s):  
Water Resources ◽  
River Basin ◽  
Transition Probability ◽  
Conversion Model ◽  
Drought And Flood ◽  
Runoff Prediction ◽  
Runoff Forecast ◽  
Hanjiang River ◽  
Basin Area ◽  
Regional Water

Abstract Runoff prediction has an important guiding role in the planning and management of regional water resources, flood prevention and drought resistance, and can effectively predict the risk of changes in regional water resources. This study used 12 runoff prediction methods to predict the runoff of four hydrological stations in the Hanjiang River Basin (HRB). Through the MCMC method, the HRB runoff probability conversion model from low to high (high to low) is constructed. The study found that the runoff of the HRB had a decreasing trend. In the mid-1980s, the runoff had a significant decreasing trend. The smoother the runoff changes, the easier it is to make accurate prediction. On the whole, the QS-MFM, MFM, MA-MFM, CES and DNN methods have strong generalization ability and can more accurately predict the runoff of the HRB. The Logistic model can accurately simulate the change of runoff status in the HRB. Among them, the HLT station has the fastest conversion rate of drought and flood, and the flow that generates floods is 6 times that of drought. The smaller the basin area, the larger the gap between drought and flood discharge. Overall, this research provides important technical support for the prediction of change in water resources and the transition probability from drought to flood in the HRB.

scholarly journals Optimal Water Allocation Based on Water Rights Transaction Models with Administered and Market-Based Systems: A Case Study of Shiyang River Basin, China

Water ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 577 ◽  
Author(s):  
Lizhen Wang ◽  
Yong Zhao ◽  
Yuefei Huang ◽  
Jianhua Wang ◽  
Haihong Li ◽  
...  
Keyword(s):  
Water Resources ◽  
River Basin ◽  
Water Allocation ◽  
Water Rights ◽  
Water Saving ◽  
Allocation Model ◽  
Transaction Model ◽  
Shiyang River Basin ◽  
The Impact ◽  
Optimal Water Allocation

Water-rights trade has proved to be an effective method for coping with water shortages through the transfer of water resources between users. The water allocation system is classified into two categories based on information transparency and water rights transaction goals: administered system (AS) and market-based system (MS). A multi-agent and multi-objective optimal allocation model, built on a complex adaptive system, was introduced to direct the distribution of water resources under an AS in the Shiyang River Basin; it was compared with a market-based water rights transaction model using the bulletin-board approach. Ideal economic agent equations played a dominant role in both models. The government and different water users were conceptualized as agents with different behaviors and goals in water allocation. The impact of water-saving cost on optimal water allocation was also considered. The results showed that an agent’s water-saving behavior was incentivized by high transaction prices in the water market. Under the MS, the highest bid in the quotation set had a dominant influence on how trade was conducted. A higher transaction price will, thus, result in a better benefit ratio, and a lower one will result in inactivity in terms of water rights trade. This will significantly impact the economic benefit to the basin.

Time-scale dependent mechanism of atmospheric CO2 concentration drivers of watershed water-energy balance

2021 ◽  
Author(s):  
Jing Zhao
Keyword(s):  
Energy Balance ◽  
River Basin ◽  
Time Scales ◽  
Time Scale ◽  
Hydrological Processes ◽  
Multiple Time Scales ◽  
Multiple Time ◽  
The Wei River Basin ◽  
Balance Dynamics ◽  
The Impact

<p>The elevated atmospheric carbon dioxide concentration (CO<sub>2</sub>), as a key variable linking human activities and climate change, seriously affects the watershed hydrological processes. However, whether and how atmospheric CO<sub>2</sub> influences the watershed water-energy balance dynamics at multiple time scales have not been revealed. Based on long-term hydrometeorological data, the variation of non-stationary parameter n series in the Choudhury's equation in the mainstream of the Wei River Basin (WRB), the Jing River Basin (JRB) and Beiluo River Basin (BLRB), three typical Loess Plateau regions in China, was examined. Subsequently, the Empirical Mode Decomposition method was applied to explore the impact of CO<sub>2</sub> on watershed water-energy balance dynamics at multiple time scales. Results indicate that (1) in the context of warming and drying condition, annual n series in the WRB displays a significantly increasing trend, while that in the JRB and BLRB presents non-significantly decreasing trends; (2) the non-stationary n series was divided into 3-, 7-, 18-, exceeding 18-year time scale oscillations and a trend residual. In the WRB and BLRB, the overall variation of n was dominated by the residual, whereas in the JRB it was dominated by the 7-year time scale oscillation; (3) the relationship between CO<sub>2 </sub>concentration and n series was significant in the WRB except for 3-year time scale. In the JRB, CO<sub>2 </sub>concentration and n series were significantly correlated on the 7- and exceeding 7-year time scales, while in the BLRB, such a significant relationship existed only on the 18- and exceeding 18-year time scales. (4) CO<sub>2</sub>-driven temperature rise and vegetation greening elevated the aridity index and evaporation ratio, thus impacting watershed water-energy balance dynamics. This study provided a deeper explanation for the possible impact of CO<sub>2</sub> concentration on the watershed hydrological processes.</p>

scholarly journals Understanding Future Water Challenges in a Highly Regulated Indian River Basin—Modelling the Impact of Climate Change on the Hydrology of the Upper Narmada

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1762 ◽  
Author(s):  
Nathan Rickards ◽  
Thomas Thomas ◽  
Alexandra Kaelin ◽  
Helen Houghton-Carr ◽  
Sharad K. Jain ◽  
...  
Keyword(s):  
Climate Change ◽  
Water Resources ◽  
River Basin ◽  
Large Scale ◽  
Monsoon Season ◽  
Future Climate Change ◽  
Impact Of Climate Change ◽  
Global Circulation Models ◽  
The Impact ◽  
Availability Assessment

The Narmada river basin is a highly regulated catchment in central India, supporting a population of over 16 million people. In such extensively modified hydrological systems, the influence of anthropogenic alterations is often underrepresented or excluded entirely by large-scale hydrological models. The Global Water Availability Assessment (GWAVA) model is applied to the Upper Narmada, with all major dams, water abstractions and irrigation command areas included, which allows for the development of a holistic methodology for the assessment of water resources in the basin. The model is driven with 17 Global Circulation Models (GCMs) from the Coupled Model Intercomparison Project Phase 5 (CMIP5) ensemble to assess the impact of climate change on water resources in the basin for the period 2031–2060. The study finds that the hydrological regime within the basin is likely to intensify over the next half-century as a result of future climate change, causing long-term increases in monsoon season flow across the Upper Narmada. Climate is expected to have little impact on dry season flows, in comparison to water demand intensification over the same period, which may lead to increased water stress in parts of the basin.

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