Study on formation and expansion condition of hidden soil cavity under condition of groundwater exploitation in karst areas

2017 ◽  
Vol 76 (7) ◽  
Author(s):  
Yongyao Wei ◽  
Sulin Sun
1999 ◽  
Vol 39 (10-11) ◽  
pp. 353-356 ◽  
Author(s):  
Gideon Tredoux ◽  
Peter King ◽  
Lisa Cavé

The Atlantis Water Resource Management Scheme uses artificial recharge of urban stormwater and treated wastewater to augment the natural groundwater resource. The key to the success of the scheme is the fractionation of the stormwater into components of distinctly different quality, and the separate treatment of domestic and industrial wastewater for different end-uses. The groundwater exploitation strategy is largely controlled by water quality requirements. Reuse of domestic and industrial wastewater depends on quality parameters. Tertiary treated domestic effluent is destined for indirect reuse via the aquifer, while treated industrial wastewater is used together with spent regenerant brine and stormwater from the noxious trade area for preventing seawater intrusion. Both residential and industrial stormwater is separated into the base flow and storm flow components and utilised for various purposes. The sustainable operation of the water resource scheme serves as a prototype for the optimal use of water and protection of the environment.


Forests ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 83
Author(s):  
Yuzhi Tang ◽  
Quanqin Shao ◽  
Tiezhu Shi ◽  
Guofeng Wu

Forest stand volume is one of the key forest structural attributes in estimating and forecasting ecosystem productivity and carbon stock. However, studies on growth modeling and environmental influences on stand volume are still rare to date, especially in subtropical forests in karst areas, which are characterized by a complex species composition and are important in the global carbon budget. In this paper, we developed growth models of stand volume for all the dominant tree species (groups) (DTSG) in a subtropical karst area, the Guizhou Plateau based on an investigation of the effects of various environmental factors on stand volume. The Richards growth function, space-for-time substitution and zonal-hierarchical modeling method were applied in the model fitting, and multiple indices were used in the model evaluation. The results showed that the climatic factors of annual temperature and precipitation, as well as the site factors of stand origin, elevation, slope gradient, topsoil thickness, site quality degree, rocky desertification type and rocky desertification degree, have significant influences on stand volume, and the topsoil thickness and site quality degree have the strongest positive effect. A total of 959 growth equations of stand volume were fitted with a five-level stand classifier (DTSG–climatic zone–site quality degree–stand origin–rocky desertification type). All the growth equations were qualified, because all passed the TRE test (≤30%), and the majority of the R2 ≥ 0.50, above 70% of the RMSE were between 5.0 and 20.0, and above 80% of the P ≥ 75%. These findings provide updated knowledge about the environmental effect on the stand volume growth of subtropical forests in karst areas, and the developed stand volume growth models are convenient for forest management and planning, further contributing to the study of forest carbon storage assessments and global carbon cycling.


Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4002
Author(s):  
Anamaria Iulia Török ◽  
Ana Moldovan ◽  
Erika Andrea Levei ◽  
Oana Cadar ◽  
Claudiu Tănăselia ◽  
...  

Lithium is a critical element for the modern society due to its uses in various industrial sectors. Despite its unequal distribution in the environment, Li occurrence in Romania was scarcely studied. In this study a versatile measurement method using ICP-MS technique was optimized for the determination of Li from various matrixes. Water, soil, and plant samples were collected from two important karst areas in the Dobrogea and Banat regions, Romania. The Li content was analyzed together with other macro- and microelement contents to find the relationship between the concentration of elements and their effect on the plants’ Li uptake. In Dobrogea region, half of the studied waters had high Li concentration, ranging between 3.00 and 12.2 μg/L in the case of water and between 0.88 and 11.1 mg/kg DW in the case of plants, while the Li content in the soil samples were slightly comparable (from 9.85 to 11.3 mg/kg DW). In the Banat region, the concentration of Li was lower than in Dobrogea (1.40–1.46 μg/L in water, 6.50–9.12 mg/kg DW in soil, and 0.19–0.45 mg/kg DW in plants). Despite the high Li contents in soil, the Li was mostly unavailable for plants uptake and bioaccumulation.


2009 ◽  
Vol 45 (6) ◽  
pp. 517-524 ◽  
Author(s):  
A. A. Baryakh ◽  
E. P. Rusin ◽  
S. B. Stazhevsky ◽  
A. K. Fedoseev ◽  
G. N. Khan

2021 ◽  
Vol 13 (14) ◽  
pp. 2668
Author(s):  
Tamás Telbisz

Conical hills, or residual hills, are frequently mentioned landforms in the context of humid tropical karsts as they are dominant surface elements there. Residual hills are also present in temperate karsts, but generally in a less remarkable way. These landforms have not been thoroughly addressed in the literature to date, therefore the present article is the first attempt to morphometrically characterize temperate zone residual karst hills. We use the methods already developed for doline morphometry, and we apply them to the “inverse” topography using LiDAR-based digital terrain models (DTMs) of three Slovenian sample areas. The characteristics of hills and depressions are analysed in parallel, taking into account the rank of the forms. A common feature of hills and dolines is that, for both types, the empirical distribution of planform areas has a strongly positive skew. After logarithmic transformation, these distributions can be approximated by Inverse Gaussian, Normal, and Weibull distributions. Along with the rank, the planform area and vertical extent of the hills and dolines increase similarly. High circularity is characteristic only of the first-rank forms for both dolines and hills. For the sample areas, the the hill area ratios and the doline area ratios have similar values, but the total extent of the hills is slightly larger in each case. A difference between dolines and hills is that the shapes of hills are more similar to one another than those of dolines. The reason for this is that the larger, closed depressions are created by lateral coalescence, while the hills are residual forms carved from large blocks. Another significant difference is that the density of dolines is much higher than that of hills. This article is intended as a methodological starting point for a new topic, aiming at the comprehensive study of residual karst hills across different climatic areas.


Author(s):  
Lianheng Zhao ◽  
Shan Huang ◽  
Zhonglin Zeng ◽  
Rui Zhang ◽  
Gaopeng Tang ◽  
...  

Author(s):  
Long-Bo Li ◽  
Xiao-Dan Wang ◽  
Ping Zhang ◽  
Yao-Qiang Zhu ◽  
Ming-Qiang Ren ◽  
...  
Keyword(s):  

Land ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 74
Author(s):  
Yuanqing Li ◽  
Kaifang Shi ◽  
Yahui Wang ◽  
Qingyuan Yang

The quantitative evaluation of the suitability of land fallow is of great significance to the effective implementation of fallow system in rural China. The purpose of this study is to systematically evaluate the cultivated areas suitable for fallow in Chongqing, China. The results show that: (1) a comprehensive index of cultivated land fallow (ILF) was developed by employing a series of multi—source data, and the ILF has been proven as an effective proxy to identify the cultivated areas suitable for fallow; (2) cultivated land with ILF values above the average value accounts for 34.38% (9902 km2) of the total cultivated land; (3) the ILF is negatively correlated with the population density, transportation proximity, and proportion of inclined area. This study argued that the ILF can reflect the cultivated areas suitable for fallow in Chongqing and can provide guidance for the spatial distribution of cultivated land fallow. The findings indicated that the differences in geographical elements between karst and non—karst areas must be further investigated, and the evaluation accuracy of the cultivated areas suitable for fallow must be improved.


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