中国岩溶

Drought causes and restoration measures for Jiulongchi spring group within Cuihu lake, Kunming

WANG Yu, HE Rao-sheng, LIU Hai-feng, WANG Zi-wei, YAN Xiang-sheng, SHUANG Ling, PENG Shu-hui

2014, 33(3): 263-271.

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The Jiulongchi spring group is located in the northern part of the Kunming basin. The karst aquifer system in this area extends from the bare karst mountain zone of the Sheshan hill to the loose soil zone at the bottom of the Kunming basin. Due to the facts that the soil layer of Cuihu lake district is very thin and groundwater infiltration is blocked by the clastic rock strata at the southern side, the groundwater rises and overflows the surface over a short period, forming the Jiulongchi spring group. The Jiulongchi spring group is not only the source of Cuihu lake, but also one of the sources for Dianchi lake. The drought of the Jiulongchi spring group reflects serious deterioration of the water environment in Dianchi lake basin. Based on dynamic groundwater monitoring data from the 1960's, groundwater exploitation data, groundwater drainage excavation and the expansive rocky desertification in the groundwater recharge area of Sheshan karst hill, it is proved that the unsustainable large-scale development and underground channel construction in the area were the primary causes of the drought of the Jiulongchi spring group. Many of the restoration measures are very effective, such as closing production wells, shutting down underground shelters, and transferring long-distance water from outside of Dianchi basin into the basin. It is noted that the groundwater level around the Jiulongchi spring group started to rise after the measures were implemented.

Boundary condition, water cycle and water environment changes in the Jinan spring region

SUN Bin, PENG Yu-ming

2014, 33(3): 272-279.

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The Jinan spring region is the area in Jinan City with spring flow and subterranean water storage. Four spring groups, namely, Baotu, Heihu, Wulongtan and Zhenzhu, are identified in the center of the northern city area. Protection of karst groundwater in the Jinan spring region is critical for sustainable utilization. In this paper, several sensitive aspects of the karst area, including boundary conditions, underground channels in karst, water cycle characteristics and changes in water quality are discussed using spring flow analysis, analysis of the flow field characteristics, artificial groundwater recharge estimation and investigation of self-drilled wells. The boundary conditions in the Jinan spring region were re-defined. The eastern boundary was extended 4 km eastward in the northern permeable section of the original boundary. Using karst stratified statistics and buffer analysis of drilling it was concluded that there is a 100 to 150 m deep groundwater flow zone in the direction of Dangjiazhuang, Shiliuli river and Qianfoshan fault (Quancheng park section). Additionally, the water cycle of Wulongtan and Zhenzhu springs is dominated by deep circulation, while Baotu spring and Heihu spring are affected by both shallow and deep circulation. Baotu spring is mainly recharged by karst groundwater and surface water in west and south Jinan, while Heihu spring receives a certain amount of karst water from the southeast region. It is notable that the karst water quality is deteriorating. Therefore, the ecological environment of the karst area in the southern Jinan spring region, and particularly the surrounding rivers and reservoirs, needs to be addressed urgently.

Application of the numerical simulation method in concealed karst wellhead for protection area delimitation and contamination prevention

LI Xing-yu, NAN Tian, WANG Xin-juan, LI Peng, XIE Zhen-hua, SHAO Jing-li

2014, 33(3): 280-287.

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A wellhead protection area (WHPA) is an effective technical method and basic standard for safeguardking groundwater resources. Frequently-used methods for WHPA delimitation include the empirical approach, analytical methods, tracing tests and numerical simulation. Of these, numerical simulation is preferred for complicated hydrogeological conditions. It is quite difficult to use numerical simulation methods in WHPA delimitation for a concealed karst aquifer, as a result of its heterogeneity, anisotropy, parameter uncertainty and development under Quaternary or other bedrock. This study takes two groundwater sources, Daxing Niantan wellhead and Tongzhou Longwangzhuang wellhead, which are located in the concealed karst system southeast of Beijing, as examples to study the numerical simulation method of WHPA delimitation. The numerical simulation model, which takes the three-dimensional transient flow of Quaternary and karst aquifer into consideration, is established by the GMS. Then particle tracing technology is used to confirm the WHPA, taking a tracing time of 100 days as the primary protection zone and 1,000, days as the secondary protection zone. Related pollution-control measures are proposed according to the WHPA results. Additionally, given that leakage from the overlying Quaternary loose-porosity aquifer is the primary recharge source for the concealed karst aquifer, the boundary of the Quaternary WHPA is as the same as the boundary of the karst WHPA. Control of the Quaternary water contamination needs to be enhanced to prevent pollution of the karst water.

The relationship between karst formation and geological disasters in Qingjiang river basin, western Hubei Province

CHANG Hong, ZHANG Yu, LI Jing-fu, TAN Jian-min, HAN Hui-qing

2014, 33(3): 288-293.

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Carbonate rocks are widely distributed in the Qingjiang river basin in western Hubei Province. Karst geological disasters often take place in this area. Based on a survey of geological disaster in 11 counties, the relationship between karst formation and geological disasters is analyzed and evaluated using statistical and analogical methods. The relationship is summarized in four main points, (1) Karst cave systems may cause karst collapse and disaster chains. (2) Landslides or avalanches are induced by karstification and enhanced by fractures expansion under the karst dissolution process. Dangerous rocks or potentially unstable slopes are generally linked with karst dissolution and weathering. (3) It is indicated that calcareous cementation among rocks can enhance the stability of landslides and avalanches. (4) For the case study in Xintang stone forest, karst phenomena and landslides were identified. It is proposed that it is necessary to investigate the karst background of disaster areas, and evaluate the impact of calcareous cementation on the stability of landslides and avalanches by studying its distribution and reinforcement effects.

Evolution and numerical simulation of a karst soil cave

JIA Long, MENG Yan, GUAN Zhen-de

2014, 33(3): 294-298.

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Soil caves in karst areasarea concealed and adverse geological phenomena. The evolution of a soil cave can cause uneven displacement and stress redistribution on the overlying soil layer, conversely changes in displacement and stress can be used to study soil cave evolution using three-dimensional finite-difference software FLAC3D. The vertical displacement field of the soil layer shows that, the maximum vertical displacement taking place on the arch roof of the soil cave may cause tensile failure of the arch roof. Based on the level of soil layer displacement on the arch roof, an "equal settlement plane" can be drawn to determine the depth of the soil cave. The shear stress field of the soil layer indicates that, the maximum shear stress in the arch toes can cause arch toe shear failure, and the "low shear stress area" can be used to determine the impact of the arching effect on the overlying soil layer. Through analysis of the plastic zone of the soil layer, it is concluded that, in rigid clay areas, soil caves with barrel bottle-shaped pit collapse were mainly caused by arch roof collapse and tensile failure; while in areas of loose soil, caves with taper or plate-shaped pit collapse resulted from shear failure of the arch toe. The low shear stress area, equal settlement plane and plastic zone can be adopted to evaluate the stability of soil caves and the limits on hole size in the overlying layer. Evolution and numerical simulation of karst soil caves in this study provide important theoretical and engineering results for monitoring and evaluation of early stage karst collapse.

Formation conditions and mechanisms of karst subsidence: A case study of Huangzhuang village in Tangshan

LI Yan-gui, LIU Zi-long, YU Xiao-min, LUO Shui-yu, YONG Fan, JIANG Zheng-zhong

2014, 33(3): 299-307.

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In order to evaluate the geological conditions and the mechanisms of karst collapse in the Tangshan area, the impacts of karst geology, lithology and hydrogeological conditions on karst collapse in the region were evaluated using integrated geophysics means, borehole drilling technology, groundwater long-term observation, etc. Geological conditions, mechanisms of surface karst collapse, collapse forecast and development trends were investigated using two-dimensional and three-dimensional Electrical Resistivity Tomography (ERT) data.The distribution of karst collapse on a three-dimensional scale, the underground flow channel and the basement distribution were also evaluated. It is included that karst collapse mainly takes place in areas with extensive cone of depression zones and underground flow channels, the locations in which main flow channel and in particular with frequent interaction with surface water, which often occurs in the rainy season. The study of karst collapse using three-dimensional ERT data and three-dimensional inversion technology help characterize the karst development and the quaternary aquifer.

Evaluation of ecological security in the Wujiang river basin using remote sensing and GIS technologies

YI Wu-ying, SU Wei-ci

2014, 33(3): 308-318.

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To understand the situation and existing environmental protection problems, and to promote coordinated development of the Wujiang river basin economy and ecological construction, the environmental ecological safety of the Wujiang river basin is evaluated in this paper. Applying the RS and GIS techniques, on basis of analyzing the changes of watershed land use and the space-time changes of landscape pattern,an assessment system for ecological security is builded by natural environment,economy and landscape ecology.And with this assessment system,integrating entropy method with attribute identification model,the ecological security of 41 regions of the watershed are assessed. The evaluation results are divided into five categories: good, moderately-good, medium, moderately-bad and bad. The results indicate that: in 2000 the Wujiang river basin had 745.8 km2 (1.13%) of bad, 15,212.2 km2 (23.05%) of moderately-bad, 40,670.7 km2 (61.63%) of medium, and 9,361.4 km2(14.19%) of moderately-good conditions. It is noted that there are some differences between the results for 2000 and those for 2010. In 2010, the Wujiang river basin had 4,330.5 km2(6.58%) of bad, 12,254.1 km2(18.57%) of moderately-bad, 42,804.0 km2(64.86%) of medium and 6,591.4 km2(9.99%) of moderately-good conditions. No good conditions occurred in the Wujiang river basin in 2000 and 2010. However, compared with 2000, the moderately-bad area increased in 2010, and the moderately-good area decreased, indicating that ecological environment is facing a negative trend. The ecological security situation in the upper and the middle catchment is poorer than that in the lower catchment of the Wujiang river basin. In the lower catchment, the problem of hydropower resources over-exploitation is very serious, while in the middle catchment, mining of mineral resources and high population density in big cities play significant roles in ecological security. In the upper catchment, the main problems which affect ecological security include the fragility of the ecological environment, the serious contradiction between people and land, and the problems of soil and water loss and rocky desertification. In summary, the ecological security in the karst area is very fragile, and unreasonable development and utilization of natural resources and the environment leads to deterioration of the ecological environment. In order to ensure sustainable development of the natural and social economy in the Wujiang river basin, it is suggested that the protection of ecosystem, ecological reconstruction, and the systematic research on ecological restoration be strengthened.

Spatial heterogeneity of soil nutrients and pH in tobacco area based on geostatistics: A case study in a karst area of Youyang county, Chongqing

LIU Yue-jiao, ZHANG Yang, NI Jiu-pai, ZHOU Chuan

2014, 33(3): 319-325.

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Evaluation of spatial heterogeneity of soil nutrients and pH forms a basis for management of soil nutrients and fertilization in tobacco-growingareas. In this paper, the spatial heterogeneity of soil nutrients and pH in the tobacco-growing area of Youyang county was evaluated using classical statistics and geostatistics. The results indicated rich organic matter and poor availability of phosphorus in the study area; the variation coefficients for eight soil nutrient indicators ranged from 13.11% to 71.46%. The variable coefficient of available phosphorus was the largest among the indicators, while organic matter, total nitrogen and available nitrogen were stable. A significant positive correlation between organic matter and total nitrogen, total phosphorus, available nitrogen and available phosphorus was noticed, while a clear negative correlation between pH and both available phosphorus and potassium was identified. The semivariograms for soil organic matter, total nitrogen, total phosphorus and available potassium were all well fitted using the exponential curve model, while the correlation between pH and available nitrogen fitted well using the spherical model; total nitrogen, total phosphorus, available nitrogen and potassium had moderate spatial correlation, and other soil nutrient indicators showed weak spatial correlation. The spatial distribution of soil nutrients and pH in the east-west direction and the north-south direction area is significantly different, and the variation of spatial distribution in the east-west direction was larger than in the north-south direction. The spatial correlation of soil nutrients in tobacco-growing area of Youyang county is not significant, therefore, it can be concluded that the spatial heterogeneity of soil nutrients is mainly affected by the topography, fertilization, tillage and other potential factors.

Spatial patterns and factors impacting settlements in Hongfeng lake watershed

WANG Fa-yan, LI Yang-bing

2014, 33(3): 326-337.

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This study aims to explore the spatial patterns of settlements and the underlying regional rules in the Hongfeng lake watershed, the results of which would provide a scientific basis for settlement optimization and regulation. Based on the Thematic Mapper (TM) images of Hongfeng lake watershed in 2000, 2005 and 2010, data for settlements, tourism-use areas, roads and rivers were extracted with the aid of Erdas8.5, ArcGIS9.3 software. The Hongfeng lake watershed was divided into a 1,000 m × 1,000 m grid with the percentage of settlements in each grid square calculated to determine settlement size-grade. The spatial distribution of settlements was converted to density figures using the Kernel Density function in Spatial Analyst Tools, and road and river buffer areas were determined. The results showed that in the Hongfeng lake watershed settlement numbers and area are rising (the number of settlement patches increased from 852 to 2,592, total area increased from 1,204.3 ha to 4,200 ha, and the average settlement density rose from 0.44/km2to 1.33/km2). A high area percentage of settlements and high settlement density are found in flat areas. Changes in the spatial distribution of the area of settlements and the settlement density are generally consistent. Small settlement patches grow rapidly. Settlement growth is mainly from farmland. Settlement expansion mainly occurs in scattered, banded and massive extensions. The spatial forms of the settlements are mostly scattered points, branches, and rules. Roads have a significant influence on settlement distribution. However, the influence of rivers is gradually declining. The total area of residential zones tends to decrease with increases in slope, but increases with the rate of settlement in 25°-80°areas.

Factors affecting household behavior to control rocky desertification based on Logistic-ISM model in karst area

YU Shuang, LI Guang

2014, 33(3): 338-346.

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Restoration of rocky desertification by households in karst areas is vital for the ecological security of the Yangtze River and Pearl River Basins. In order to understand the factors affecting household behavior to control rocky desertification, and promote implementation and management in effective prevention of rocky desertification, three typical counties with rocky desertification conditions were selected for the case study: Qinglong, Guanling, and Qianxi. The behavior of 437 households with respect to control of rocky desertification was investigated using the participatory rural appraisal method. Based on the survey data, Logistic regression analysis and the ISM method were used to determine factors affecting household behavior to control rocky desertification and their hierarchy structure. The results indicate that the distance between home and the nearest rural market, voluntary, numbers of contact information, numbers of exchange information are direct factors; the rocky desertification area is an indirect factor; household agricultural income, volunteering for scientific research projects, and the number of visits by experts are root factors. Therefore, low agricultural income, lack of funding and lack of technology for rocky desertification control are the fundamental causes of farmers’ low enthusiasm for rocky desertification control. With that in mind, it is suggested that increasing farmers’ income through multiple channels to promote their enthusiasm for rocky desertification control, increasing investment in rural infrastructure to reduce the cost of rocky desertification control, and improving the technical system of rocky desertification control to advance farmers’ desertification control skills should be priorities.

Comprehensive evaluation of soil fertility in karst area by GIS and improved Grey Relation Model：A case study in Fengdu county karst area, Chongqing

SUN Yu, GAO Ming, WANG Dan, DENG Wei, CHEN Cheng-Long

2014, 33(3): 347-355.

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Soil fertility evaluation can provide the basis for rational fertilization and agricultural production structure adjustment. Under the technical support of GIS, we take Fengdu county karst area as research object and collected 316 soil sample of this county, according to topographical features, land use status and soil types. In this paper, we report organic matter, total nitrogen, available nitrogen, available phosphorus, available potassium, available sulfur, available cuprum, available iron, available manganese, available zinc, available boron content and pH for all soil samples. Based on data, we evaluated the soil fertility of the county by using Grey Relation Model improved by principal component analysis and membership function, and discussed the special distribution characteristics by using statistical methods. The study shows that the soil integrated fertility index (IFI) in the study area ranged from 0.352 to 0.881 with the average value of 0.579 in the study area. Geostatistical trend analysis of IFI presented a one-order (linear) global trend and semi-variance analysis of the residuals showed a weak degree of spatial correlation. Overall fertility quality in the study area is middle or better, the second soil fertility grade region accounted for 10.61%, the third soil fertility grade region accounted for 31.09%, and the fourth soil fertility grade region accounted for 35.94%. The contribution rates for integrated fertility of soil conventional nutrient indexes and microelement indexes were 76.77% and 23.23%, respectively. Therefore, bringing microelement indexes into the soil fertility evaluation index system is reasonable and practicable, the improved Grey Relation Model can quantitatively evaluate integrated soil fertility, and the geostatistical method can satisfactorily reveal spatial variation patterns in soil fertility.

Study of simulated soil erosion on a bare karst slope

LIU Zheng-tang, DAI Quan-hou, YANG Zhi

2014, 33(3): 356-362.

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Karst is widely distributed in China where carbonate rocks, including buried karst, account for up to 3,463,000 km2. Strata with carbonate rock formations comprise 2,060,000 km2, while carbonate rocks outcrop over 907,000 km2.The karst system, which is faces serious soil erosion problems, is an ecologically fragile system due to its high sensitivity, low catastrophe capacity and small environmental capacity. Therefore, study of soil erosion in karst areas is important. The impacts of fissure porosity, bedrock outcrop percentage and rainfall intensity on underground runoff and sediment yield were evaluated using simulated rainfall. The results provide a theoretical basis for future evaluation and prevention of soil erosion in karst areas. The results showed; (1) Soil erosion has a high correlation with porosity or fracture aperture; (2) Soil infiltration rate is dependent on rainfall. Surface and subsurface suspended sediment decrease with rainfall duration, while surface bed material load increases; (3) In general, the amount of surface runoff and sediment decreases with the bedrock outcrop rate, while the amount of underground runoff and sediment increases; (4) Only suspended sediment loss took place on the surface. No bed material load loss occurred with rainfall intensity of 30 mm/h. The runoff and sediment yield increase with rainfall intensity. For instance, when rain intensity increased from 30 mm/h to 150 mm/h, the cumulative surface runoff was 538.5 L, cumulative surface sediment yield 2,393.81 g, cumulative underground runoff 207.8 L and cumulative underground sediment yield 687.83 g. The rate of increase in the cumulative sediment yield is greater than the rate of increase in the cumulative runoff, and the rate of increase in the surface runoff and sediment yield is greater than that of the underground runoff and sediment yield; (5) The correlation between soil erosion and each individual factor indicates that the relative impact of each factor on soil erosion is, rainfall duration ＞ rainfall intensity ＞ underground porosity ＞ bedrock outcrop.

Seasonal temperature changes in Shennonggong and Xianglong caves and their potential impact on oxygen isotope composition of stalagmite carbonate

ZHANG He-qiao, CAI Yan-jun, ZHANG Hai-wei, TAN Liang-cheng, QIN Shi-jiang

2014, 33(3): 363-372.

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Consecutive 19-month temperature measurements in Shennonggong and Xianglong caves were conducted synchronously. The results indicate that the temperature was not stable in both caves, but oscillated on both hourly and seasonal time scales. Temperature data from inside and outside the caves show that in Shennonggong cave the temperature fluctuated more significantly during the summer season than in winter, revealing the impact of the amount of precipitation on the cave temperature. On the other hand, in Xianglong cave the amplitude of temperature oscillations is smaller during summer than in winter, implying that the chamber structures limit ventilation during the summer as it is hard for cold cave air in to flow out the high opening of the cave. The temperature inside the cave corresponds well with temperature outside the cave, with summer-winter temperature differences of 4.8 ℃ (4.6 ℃ at second site) and 3.2 ℃ in Shennonggong and Xianglong caves, respectively. The cave temperature response time to outside temperature changes varied seasonally at both cave sites. The lags in the decrease of cave temperature at the end of autumn were longer than those of the temperature increase at the end of spring in both caves. The different lags are likely due to the relatively high temperature in the deeper surrounding rock,the seasonal changes of the thermal conductivities of the air and the surrouding rock, as well as effects of seasonally changes in precipitation. It is noted that modern observations have shown the speleothem calcite may deposit only during the summer or winter (e.g., summer deposition mode or winter deposition mode). Thus, it may be deduced that the shift in speleothem growth seasons (deposition mode) may induce significant calcite δ18O changes in caves with large seasonal temperature changes.

Karst landforms and reservoir characteristics in the Ordovician strata of Lungu 7,Tabei uplift

ZHANG Qing-yu, QIN Feng-rui, LIANG Bin, CAO Jian-wen, DAN Yong, LI Jing-rui

2014, 33(3): 373-378.

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The Tabei uplift of the Tarim basin is one of the three largest ancient uplifts. Lungu7 well block is located in the northern uplift in Lunnan buried hill in the primary geomorphic unit karst highland, high area of Lunnan low raise. It is rich in oil and gas resources, and the Ordovician carbonates are one of the richest oil-bearing series, and one of the main formations for exploration and development. The different geomorphic units control the ancient hydrodynamic conditions, and further determine the diversity of karst development. Therefore, the precise shape of the karst paleogeomorphology is of great significance for the reasonable arrangement of high production and efficient wells. This study uses the relative residual thickness method to characterize ancient karst landforms and ancient hydrodynamic conditions. Two types of secondary geomorphic unit are classified, karst highland and karst slope. Furthermore, six types of tertiary geomorphic unit are classified after the precise description of the secondary geomorphic unit on the basis of combinations of micro-geomorphologic landforms. Through further research on the karst reservoir distribution pattern, this study considered that the reservoir volume is mainly comprised of secondary solution pores, corrosion cracks and cave systems, formed by later structure and karstification. According to the combined characteristics of the holes, caves and seams, as well as the relationship between fracture porosity and hole porosity, the Ordovician Yingshan karst reservoirs are divided into four types, fracture, hole, crack-hole, and cave. Compared to karst slopes, karst highlands more easily preserve karst reservoir space due to stronger denudation. The karst slope zone easily forms a large fracture-cave cube because of it strong hydrodynamic conditions, well-developed karst piping system and good connectivity. It can be treated as karst cave reservoir, which provides the basis for future exploration and development.

Review of foreign research on speleotherapy

LI Xi, YANG Xiao-xia, XIANG Xu, SHI Ding-fang

2014, 33(3): 379-385.

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Speleotherapy, a new medical approach, makes use of caves as special medical sites. It is a new form of cave resource utilization, with great potential for further development. Speleotherapy terms, including "speleotherapy", "cave therapy", "cave treatment" and "halotherapy" were used as keywords to search the Web of Science database, and 32 papers from 1978 to 2013 were retrieved. It was determined that speleotherapy research has mainly focused on the origin and development of speleotherapy, the medical function of caves, mechanisms of treatment in respiratory and clinical application, radon concentration measurement and prevention in therapeutic caves and medical tourism. However, it is clear that some problems remain, such as the rather limited number of studies and non-comprehensive results. Additionally, comprehensive research methods are lacking, research results are distributed unevenly in terms of geographical location and achievements using theoretical methods are relatively limited. It is suggested that future study of speleotherapy should be focused on, general applicability of the research, method diversity, medical treatment mechanisms, environmental standards for speleotherapy, cave medical tourism and halotherapy.

2014 Vol. 33, No. 3

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