Changes in soil conservation service and its driving factors: case studies in global top five largest basins

Author(s):  
Yiming An ◽  
Wenwu Zhao

<p>Soil conservation service is an important regulating ecosystem service. We estimated the soil conservation rate of the top five largest basins in the world from 2000 to 2018, classified the trend of conservation rate for each basin and each location as four types (i.e., significant decrease, decrease, increase and significant increase), and analyzed the relationships between soil conservation rate and driving factors. Results show that the Yangtze River basin produces the highest average soil conservation rate (with the value of 1429.68 t ha<sup>-1</sup> yr<sup>-1</sup>). The Yangtze, Mississippi and Yellow River basins show a generally increasing conservation trend. Partial principal component analysis between soil conservation rate and driving factors show that slope gradient has the greatest impact on soil conservation rate, followed by rainfall and NDVI. Vegetation greening (increasing NDVI) could partly offset the effect of increasing rainfall on soil conservation rate in the Mississippi and Yellow River basins. More direct and quantitative variables should be used to represent human activities to analyze the impact on soil conservation change.</p>

Author(s):  
Dongyang Xiao ◽  
Haipeng Niu ◽  
Jin Guo ◽  
Suxia Zhao ◽  
Liangxin Fan

The significant spatial heterogeneity among river basin ecosystems makes it difficult for local governments to carry out comprehensive governance for different river basins in a special administrative region spanning multi-river basins. However, there are few studies on the construction of a comprehensive governance mechanism for multi-river basins at the provincial level. To fill this gap, this paper took Henan Province of China, which straddles four river basins, as the study region. The chord diagram, overlay analysis, and carbon emission models were applied to the remote sensing data of land use to analyze the temporal and spatial patterns of carbon storage caused by land-use changes in Henan Province from 1990 to 2018 to reflect the heterogeneity of the contribution of the four basins to human activities and economic development. The results revealed that food security land in the four basins decreased, while production and living land increased. Ecological conservation land was increased over time in the Yangtze River Basin. In addition, the conversion from food security land to production and living land was the common characteristic for the four basins. Carbon emission in Henan increased from 134.46 million tons in 1990 to 553.58 million tons in 2018, while its carbon absorption was relatively stable (1.67–1.69 million tons between 1990 and 2018). The carbon emitted in the Huai River Basin was the main contributor to Henan Province’s total carbon emission. The carbon absorption in Yellow River Basin and Yangtze River Basin had an obvious spatial agglomeration effect. Finally, considering the current need of land spatial planning in China and the goal of carbon neutrality by 2060 set by the Chinese government, we suggested that carbon sequestration capacity should be further strengthened in Yellow River Basin and Yangtze River Basin based on their respective ecological resource advantages. For future development in Hai River Basin and Huai River Basin, coordinating the spatial allocation of urban scale and urban green space to build an ecological city is a key direction to embark upon.


2021 ◽  
Vol 11 (3) ◽  
pp. 145-156
Author(s):  
Van Minh NGUYEN ◽  
Elena Yurievna ZAYKOVA

Ho Chi Minh City (HCMC) is among the cities that are most at risk of fl ooding worldwide. Urbanization processes have led to a change in land use, which in turn has resulted in an increase in impervious surfaces and runoff , thus again leading to the risk of fl ooding in the city. The aim of the article is to study the impact of urban development (on the example of District 8 of HCMC) on surface runoff using a combination of the interpretation of remote sensing images of the earth (ERS) Google Earth and the SCS-CN model (the Soil Conservation Service curve number). Theoretical models are used to analyze the relationship between the typology of buildings and areas of open and impervious surfaces. The interpretation of remote sensing images was carried out in the ArcGIS program. The method used to calculate surface runoff is the Soil Conservation Service Curve Number (SCS-CN) method developed by the US Soil Conservation Service and is suitable for assessing the eff ects of land-use/land cover change due to urbanization. The results of the study show the volume of surface runoff in areas with diff erent levels of urbanization in district 8 of HCMC, assessing the impact of urbanization processes on surface runoff and revealing new opportunities for managing this process. The combination of remote sensing interpretation and SCS-CN model makes it possible to assess the impact of urban development on surface runoff . Urbanization and an increase in built-up area strongly aff ect fl ooding, reducing the soil retention.


2018 ◽  
Vol 631-632 ◽  
pp. 887-894 ◽  
Author(s):  
Lingqiao Kong ◽  
Hua Zheng ◽  
Enming Rao ◽  
Yi Xiao ◽  
Zhiyun Ouyang ◽  
...  

Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2035
Author(s):  
Lejun Ma ◽  
Huan Wang ◽  
Changjun Qi ◽  
Xinnan Zhang ◽  
Hanwen Zhang

The construction and operation of water storage and hydropower projects affects the structure of water ecosystems of downstream rivers, and the establishment of ecological flow in rivers below the water storage and hydropower projects has significant impacts on maintaining the stability of river ecosystems. A database was established based on 2000–2017 environmental impact assessment (EIA) reports on water storage and hydropower projects in China and ecological flow (e-flow) methods, and the three widely used e-flow methods for water storage and hydropower projects in China were identified on the database. Furthermore, an ecological flow satisfaction degree model was used to evaluate the methods using long series of historical hydrological data from the hydrological stations in the Yellow River basin, the Yangtze River basin, and the Liao River basin. The results showed that hydrological methods are the type most often used for water storage and hydropower projects in China, including the Tennant method, the minimum monthly average flow with 90% guarantee rate method (Mm9M method), and the measured historical minimum daily average flow rate method (MDM method). However, the ecological flow methods selected are not significantly different among different basins, indicating that the selection of ecological flow methods is rather arbitrary, and adaptability analysis is not available. The results of the ecological flow satisfaction model showed that the Tennant method is not suitable for large river basins. The results of this study can provide technical support for establishment and management decisions surrounding ecological flow.


2017 ◽  
Vol 21 (1) ◽  
pp. 169-181 ◽  
Author(s):  
Xiaomang Liu ◽  
Tiantian Yang ◽  
Koulin Hsu ◽  
Changming Liu ◽  
Soroosh Sorooshian

Abstract. On the Tibetan Plateau, the limited ground-based rainfall information owing to a harsh environment has brought great challenges to hydrological studies. Satellite-based rainfall products, which allow for a better coverage than both radar network and rain gauges on the Tibetan Plateau, can be suitable alternatives for studies on investigating the hydrological processes and climate change. In this study, a newly developed daily satellite-based precipitation product, termed Precipitation Estimation from Remotely Sensed Information Using Artificial Neural Networks – Climate Data Record (PERSIANN-CDR), is used as input for a hydrologic model to simulate streamflow in the upper Yellow and Yangtze River basins on the Tibetan Plateau. The results show that the simulated streamflows using PERSIANN-CDR precipitation and the Global Land Data Assimilation System (GLDAS) precipitation are closer to observation than that using limited gauge-based precipitation interpolation in the upper Yangtze River basin. The simulated streamflow using gauge-based precipitation are higher than the streamflow observation during the wet season. In the upper Yellow River basin, gauge-based precipitation, GLDAS precipitation, and PERSIANN-CDR precipitation have similar good performance in simulating streamflow. The evaluation of streamflow simulation capability in this study partly indicates that the PERSIANN-CDR rainfall product has good potential to be a reliable dataset and an alternative information source of a limited gauge network for conducting long-term hydrological and climate studies on the Tibetan Plateau.


Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1232
Author(s):  
Sheng-Rui Zou ◽  
Si-Xuan Du ◽  
Min Song ◽  
Ming-Xian Li

Water pollution in China has expanded from regions to river basins. It is of great significance to study the behaviors of regulated subjects from the perspective of river basins for protecting the water environment and improving the effectiveness of environmental regulations. This paper constructed a basin spatial regression design to discuss the governance effect and economic effect of water pollution from industry in relation to the central environmental protection goal of China, as well as the response and strategy of local government. Considering the validity of the data, the annual average chemical oxygen demand (COD) concentration of each monitoring station was adopted as the ambient water quality index, and there was direct evidence that the ambient water quality index influenced water-polluting industries. We found that, if the downstream COD concentration in the last year rose by 1 mg/L, the water-polluting industries reduced their pollution and output value by 1.9% and 0.2%, respectively. After using the upstream COD concentration as the tool variable, the result was still robust. However, the results of local government’s two strategies, which we can call regulatory constraint force and fiscal incentive force, were opposites. Specifically, the governance effect of polluting industries under regulatory constraints was more significant, while fiscal incentives encourage water-polluting industries to create more value. In addition, we estimated the impact of ambient water quality on water-polluting industries in the Yangtze River Basin and the Yellow River Basin, and revealed that the governance effect exceeded the average value of seven river basins. After further distinguishing the relative upstream cities and relative downstream cities, the results show that the response of relative upstream cities to water quality was significantly higher, and the gap between regions expanded further after 2013.


2018 ◽  
Vol 15 (2) ◽  
pp. 1-20
Author(s):  
Sabri Embi ◽  
Zurina Shafii

The purpose of this study is to examine the impact of Shariah governance and corporate governance (CG) on the risk management practices (RMPs) of local Islamic banks and foreign Islamic banks operating in Malaysia. The Shariah governance comprises the Shariah review (SR) and Shariah audit (SA) variables. The study also evaluates the level of RMPs, CG, SR, and SA between these two type of banks. With the aid of SPSS version 20, the items for RMPs, CG, SR, and SA were subjected to principal component analysis (PCA). From the PCA, one component or factor was extracted each for the CG, SR, and RMPs while another two factors were extracted for the SA. Primary data was collected using a self-administered survey questionnaire. The questionnaire covers four aspects ; CG, SR, SA, and RMPs. The data received from the 300 usable questionnaires were subjected to correlation and regression analyses as well as an independent t-test. The result of correlation analysis shows that all the four variables have large positive correlations with each other indicating a strong and significant relationship between them. From the regression analysis undertaken, CG, SR, and SA together explained 52.3 percent of the RMPs and CG emerged as the most influential variable that impacts the RMPs. The independent t-test carried out shows that there were significant differences in the CG and SA between the local and foreign Islamic banks. However, there were no significant differences between the two types of the bank in relation to SR and RMPs. The study has contributed to the body of knowledge and is beneficial to academicians, industry players, regulators, and other stakeholders.


Author(s):  
Irina Ulzetueva ◽  
Bair Gomboev ◽  
Daba Zhamyanov ◽  
Valentin Batomunkuev ◽  
Zorikto Banzaraktsaev

The integrated assessment of the ecological state of the main rivers of the lake Baikal basin - Verkhnyaya Angara, Tyya, Barguzin, Selenga, Snezhnaya, Bolshaya Rechka, Khilok, Chikoy is based on the assessment of the variability of the basin system under the influence of two groups of indicators: 1) Direct (immediate) impact - the volume of water intake and wastewater discharge, water use and sequential water supply. Assessment of the impact on the state of the above-listed rivers basins from wastewater was performed using the algorithm proposed by A. Korolev et al. (2007). 2) Indirect (mediate) impact - indicators of areal and linear-network impacts on the catchment area. Based on the calculation of the integral anthropogenic pressure on the territory of the above-listed river basins, only the Selenga river experiences an “average” anthropogenic load. On the territory of most river basins, the anthropogenic load is “lowered” and “low”.


2017 ◽  
Vol 727 ◽  
pp. 447-449 ◽  
Author(s):  
Jun Dai ◽  
Hua Yan ◽  
Jian Jian Yang ◽  
Jun Jun Guo

To evaluate the aging behavior of high density polyethylene (HDPE) under an artificial accelerated environment, principal component analysis (PCA) was used to establish a non-dimensional expression Z from a data set of multiple degradation parameters of HDPE. In this study, HDPE samples were exposed to the accelerated thermal oxidative environment for different time intervals up to 64 days. The results showed that the combined evaluating parameter Z was characterized by three-stage changes. The combined evaluating parameter Z increased quickly in the first 16 days of exposure and then leveled off. After 40 days, it began to increase again. Among the 10 degradation parameters, branching degree, carbonyl index and hydroxyl index are strongly associated. The tensile modulus is highly correlated with the impact strength. The tensile strength, tensile modulus and impact strength are negatively correlated with the crystallinity.


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