Types and characteristics of vulnerable eco-geological environments on the Yunnan plateau and countermeasures for ecological restoration
The geological background of the Yunnan plateau in the study area is complex, with significant uplift caused by the Himalayan orogeny, intense neotectonic movements, and pronounced variations in fault block elevation. The long-term shaping of internal and external dynamic geological processes has formed a modern ecological geological environment pattern with significant regional differences, diversity, and vulnerability. Therefore, the study of ecological vulnerability in high-altitude mountainous areas has always been an important issue facing the construction of ecological civilization in Yunnan Province. Currently, there are limited achievements in vulnerability research for specific regions within the province, and there is a lack of regional, comprehensive, and systematic research and analysis throughout the province. In order to improve the scientific compilation of national spatial planning and ecological restoration planning, as well as the feasibility and effectiveness of various restoration and governance projects, it is necessary to strengthen the investigation of ecological geological environment. Additionally, it is essential to enhance the identification and diagnosis of ecological problems, highlighting the importance of understanding these problems through the lens of nature principles, local conditions, and systematic restoration efforts. This article aims to systematically analyze the vulnerability characteristics of the ecological geological environment on the Yunnan plateau from the perspective of land and space protection and restoration in Yunnan Province. The manifestations of vulnerability are thoroughly analyzed, including geology, geomorphology, surface material composition, meteorological and hydrological characteristics, ecological patterns, etc. Based on the sensitivity of the ecological geological environment to external interference and limited self-recovery ability, four typical types of vulnerable ecological environments are identified: karst rocky mountains, plateau lakes, dry-hot valleys, and high-altitude mountainous areas. The karst rocky mountains experience severe soil erosion and water leakage, characterized by slow soil formation, limited growth, a scarcity of suitable tree species, simplistic communities, and a widespread shortage of surface water. The selection of ecological restoration models should be based on in-depth investigation and evaluation, as well as tailored plans. The plateau lakes exemplify a basin economy characterized by low carrying capacity for both resources and environment, and by both waterlogging and drought. Any adverse environmental effects resulted from ecological damage and pollution in the surrounding areas can be directly transmitted to plateau lakes through runoff, resulting in a focusing effect. The dry-hot valleys experience drought and water scarcity, with prominent water-heat contradictions. The ecological geological environment is vulnerable, and natural disasters occur frequently. There are intense soil erosion, soil degradation, and low productivity, leading to economic backwardness. Besides, agricultural, animal husbandry, and mining activities are extensive. In the high-altitude mountainous areas, the mountains are steep with intense erosion and denudation, resulting in thin and scattered soil layers. The biological conditions for plant growth are poor, and there is a strong trend towards desertification in the natural process. The ecological geological environment is vulnerable, with a high incidence of geological disasters. Human restoration is difficult and lacks sustainability. By analyzing and understanding the complex geological background, intense neotectonic movements, and the resulting vulnerability characteristics of the ecological geological environment, as well as addressing common problems and deficiencies in ecological restoration practices, we have proposed the following steps for the protection and restoration of plateau ecosystems. Firstly, we should conduct thorough research and investigation, adhering to natural and economic laws. We should carry out comprehensive and scientific research to identify the ecological geological environment and resource conditions, starting from the diversity of the ecological geological environment. We should also reveal the inherent connections and succession patterns of the ecosystem, accurately identify ecological problems, and enhance the specificity and effectiveness of ecological restoration. Secondly, we should plan the restoration in an integrated and coordinated manner and carry out the planning systematic, fully considering the differentiation of ecological geological environment. Taking the watersheds as units and considering the resources, environmental factors, and economic and social conditions of the restoration areas, we should implement comprehensive planning. This planning must align with the inherent connections among ecological elements and the principles governing material and energy transformation. Our goal is to ensure overall protection, integrated management, and systematic restoration. Thirdly, we must adhere to the principle of prioritizing protection while focusing on natural restoration. Given the vulnerability of the ecological geological environment, we should prioritize effective ecological protection by minimizing interference and destruction to vulnerable ecosystems, thereby avoiding situations that are difficult to remediate. Fourthly, we should enhance the overall coordination and guidance of national land space planning. Grounded in the principles and methods of earth system science, sustainable development theories, nature-based solutions, and relevant applied sciences, we must improve the evaluation of resources and environmental carrying capacity, as well as the suitability of national land space development within national spatial planning. This process involves thoroughly identifying the distribution and extent of ecologically vulnerable national land space, with the comprehensive consideration of factors such as precipitation distribution, vegetation cover, human interference, the significance of biodiversity conservation, and soil and water conservation to conduct resilience evaluation. Furthermore, this article proposes that while the analysis of ecological geological environment vulnerability primarily focuses on geological factors, vulnerability is closely related to human activities such as land development and utilization, climate change, and environmental pollution. Research on vulnerability should be an interdisciplinary collaboration to enhance its systematic nature and comprehensiveness. In future endeavors, the integration of ecology, geography, and geology can further broaden the content and indicators of research, thereby providing a scientific foundation for formulating more targeted policies.
Analysis of a new round of groundwater resource evaluation in Yunnan Province
Yunnan Province is located in the eastern region of the Qinghai-Tibet Plateau and the western area of the Yunnan-Guizhou Plateau. This province is characterized by mountainous plateau topography and is abundant in water resources. Groundwater resources hold great potential for development and utilization, but there is a critical issue regarding their uneven spatial distribution. Therefore, it is imperative to accurately investigate and evaluate the groundwater resources in Yunnan Province. Based on the systematic study of hydrogeological conditions in this province, its groundwater system is divided into 21 four-level basin systems and 41 five-level units for groundwater resource evaluation. In this paper, we systematically discuss the evaluation method and parameter determination for groundwater resources, and summarize and present the final evaluation results. In this evaluation, we utilized long-term rainfall data spanning from 2000 to 2020, along with the permeability coefficient and runoff modulus obtained from 1∶50,000 hydrogeological surveys conducted in Zhaotong, Yuanmou, Binchuan, Qujing, Yuxi, and other basins since 1960. Additionally, we incorporated data from the 1∶50,000 hydrogeological surveys of key karst areas in Yunnan, as well as the 1∶50,000 hydrogeological survey report of this province. We used the monitoring data from meteorological and hydrological stations to adjust the parameters of each evaluation zone in order to assess the groundwater resources in Yunnan Province. It is concluded that the average annual recharge of groundwater resources from 2000 to 2020 was 85.466 billion m3·a−1. The average annual groundwater runoff resources was 62.916 billion m3·a−1, accounting for 73.62% of the groundwater resource supply. Among them, the average annual groundwater resource supply in the Yangtze River Basin from 2000 to 2020 was 18.131 billion m3·a−1, while the average annual groundwater runoff resources during the same period was 13.942 billion m3·a−1. In contrast, the average annual groundwater resource supply in the river basins of Southwest China from 2000 to 2020 was 48.258 billion m3·a−1, with average annual groundwater runoff resources amounting to 34.106 billion m3·a−1. Besides, the average annual recharge of groundwater resources in the Pearl River Basin from 2000 to 2020 was 190.77 billion m3·a−1, and the average annual groundwater runoff resources was 148.68 billion m3·a−1. In the past 21 years, the groundwater resource supply in the Yangtze River Basin, the river basins of Southwest China, and the Pearl River Basin exhibited significant fluctuations, with the lowest supply occurring in 2011. The highest groundwater resource supply in the Yangtze River Basin was recorded in 2016. The Pearl River Basin experienced its peak supply in 2015, and the river basins of Southwest China had the highest supply in 2008. The data presented not only highlights the disparities in groundwater resources across various basins in Yunnan Province, but also serves as a crucial foundation for regional water resource management and planning. In terms of groundwater quality, the results from 223 water quality monitoring points in 2021 indicate that there were no Class I water samples detected; Class II water was found at 9 points, accounting for 4% of the total; Class III water was detected at 24 points, accounting for 10.76%; Class IV water was identified at 112 points, making up 50.22%; and Class V water was present at 78 points, which accounted for 34.98%. The types of contaminated groundwater primarily included pore water, which typically exhibited mild to moderate levels of pollution. In contrast, only a few areas were heavily polluted. Additionally, bedrock fissure water was present, but its degree of pollution was generally slight. Most of the pollutants were NH4+, F−, Fe, Mn, volatile phenols, Hg, COD, etc. The analysis of the factors influencing the quality of Class IV and Class V groundwater indicated that the most significant contributor to water quality exceeding permitted levels was the visible matter, followed by volatile phenols and manganese. In addition to the sensory index, the most influential factor was volatile phenols, followed by manganese and ammonia nitrogen. The main areas of pollution were concentrated in economically developed and densely populated cities, such as Kunming, Qujing, Yuxi, Kaiyuan, Chuxiong, Dali, and other places. In summary, although the groundwater resources in Yunnan Province are abundant, the water quality problem cannot be ignored. In the future, the protection and management of groundwater resources should be strengthened, especially in the areas with rapid economic development. The sustainable utilization of groundwater resources should be ensured by implementing stricter environmental protection policies, strengthening the monitoring and control of pollution sources, promoting water-saving technologies, and raising public awareness of environmental protection.
Analysis of geological problems and difficulties in restoration and treatment of karst environment on the Yunnan plateau
The karst region of the Yunnan plateau is characterized by high altitudes, diverse landforms, variable meteorological and hydrological conditions, and strong internal and external dynamic geological processes. Additionally, the rapid increase in human activities and the detrimental effects of unsustainable development have resulted in many issues on karst environmental geology closely related to natural resources and the environment. The main issues are rocky desertification, waterlogging and drought, groundwater pollution, spring drainage, deterioration of wetland ecological environment, and karst geological disasters. According to the data on relevant remote sensing surveys, the total area of rocky desertification in Yunnan Province in 2020 reached 24,800 km2, accounting for 26.41% of the karst area. Among them, the area of severe rocky desertification accounted for 69.46%, 20.72% for moderate rocky desertification, and 9.82% for mild rocky desertification. Rocky desertification is contiguously distributed in the karst mountainous areas of eastern and southeastern Yunnan, and in karst regions of western Yunnan, it is mostly distributed in sheets and bands. The severe rocky desertification area is mainly concentrated in the middle-height mountains, high-height mountains and valleys of the plateau karst. The distribution of waterlogging and drought in the karst region of the plateau shows obvious local characteristics. Drought disasters mainly occur in the mountainous and hilly areas with higher terrain, while waterlogging occurs more often in the valleys, basins and depressions among the mountains with lower terrain. There are 2,658,400 acres of arable land susceptible to waterlogging in karst regions of the Yunnan plateau. The degree of groundwater pollution varies greatly due to different types of groundwater, pollution protection properties and pollution sources. Generally, pore water is the most polluted with the lowest water quality. Medium to heavy pollution is mainly distributed in the middle of the basin, and the elements exceeding the permitted level mainly include nitrite, ammonia nitrogen, iron, manganese, etc. The heavily polluted areas include Kunming, Qujing, Kaiyuan, Mengzi, Gejiu and other places, mostly rated as serious or most serious pollution areas. The drainage of spring water in karst stone mountains typically results in a decline of regional groundwater levels. This decrease mainly occurs in basin areas, mining areas and the vicinity of engineering tunnel excavation, which is mainly caused by human engineering activities such as tunnel excavation, mine drainage and over-exploitation of groundwater. The wetland of the Yunnan plateau is mainly distributed in the lakeside. Due to the combined effects of ecological changes and human activities, the temporal and spatial distribution of water sources and the water cycle processes have been altered. The wetland area is shrinking, and its ecological service functions are increasingly degraded or even lost, resulting in a series of ecological and environmental geological problems. Karst geological disasters on the plateau primarily consist of karst collapses, which are mainly found in karst fault basins, trough valleys and platform areas. These collapses are mainly the result of external forces such as rainfall and earthquakes. Due to the fragility and complexity of the geological environment in karst regions of the plateau, addressing and managing various environmental geological issues is challenging, and the outcomes of restoration and control efforts are inconsistent. The main reasons can be summarized as the complex and changeable natural and social factors, resulting from issues related to the karst geological environment, the low carrying capacity of natural resources, the limited capacity of the geological environment, and the challenges in balancing survival, development and environmental protection. The economic and technical requirements for the restoration and treatment of karst environmental geological issues are increasingly demanding. Guided by the theories of hydrogeology, environmental geology and ecology, and based on a large number of detailed investigation data, this study systematically summarizes and analyzes the issues on karst environmental geology such as rocky desertification, waterlogging and drought, groundwater pollution, spring water drainage, deterioration of the wetland ecological environment, and karst geological disasters on the Yunnan plateau as well as the difficulties and causes of restoration and control of these disasters. The countermeasures and suggestions to address these issues have been put forward, which can provide the orientation and scientific basis for ecological protection and restoration.
Study on complexity of groundwater systems in the karst mining areas with abundant water on the Yunnan plateau
A mining area with abundant water usually refers to the mine with a pit water inflow greater than 10,000 m3·d−1. In view of the unevenness of the water-richness of karst aquifers and the poor accuracy of predicting water inflow, the definition of a mining area with abundant water should not be confined to the specific values of water inflow. Instead, it should be defined mainly based on the conditions of high water-richness, abundant recharge and pipeline flow of aquifers. According to the standard of hydrogeological terminology, a hydrogeological unit is defined as a groundwater system characterized by uniform recharge boundaries and conditions of recharge, runoff, and discharge. The groundwater systems described in this paper belong to the same object and category. The Yunnan plateau refers to the western section of the Yunnan-Guizhou Plateau, and, in a broad sense, encompasses Yunnan Province, which covers an area of 39.4×104 km2. The karst contiguous areas on the Yunnan plateau are mainly located in the east area of 102°E and north of the Yuanjiang river in eastern Yunnan, and the northwest and the west from Baoshan to Cangyuan. These karst contiguous areas total 11.09×104 km2, corresponding to the upper Yangtze massif, South China massif, Sanjiang orogenic belt and Tengchong orogenic belt, with superior mineralization conditions and abundant mineral resources. Historically, minerals in karst areas are primarily exploited above the erosion base. The mountainous terrain typically facilitates natural drainage, which has led to a lack of emphasis on and research into the complexity of groundwater systems in mining areas. With the growing economic and social demands, the exploration areas and mining areas are continually expanded, and are increasingly extending to deeper areas. Some deposits with abundant water that were previously challenging in exploitation have been developed. This shift has transformed hydrogeological conditions, evolving from simple to complex or even extremely complex scenarios. As a result, the challenges associated with mine water control have intensified, and the requirements for exploration have correspondingly increased. Therefore, it is both necessary and urgent to study the complexity of groundwater systems in karst mining areas with abundant water, enhance the research level, and strengthen measures for exploration control. The complexity of a system encompasses the characteristics such as disorder, sudden change, detection errors, and inference errors, which arise from the pluralism, nonlinearity, and randomness of its constituent elements, organizational structures, influencing factors, and their interrelations and interactions with the environment. Based on existing research and exploration findings, the complexity of groundwater systems in karst mining areas with abundant water is mainly reflected in the intricate and variable characteristics of system boundary conditions, hydrogeological structures, properties of water-bearing media, and the effects of mining activities. In karst areas, the geological processes of mineralization and subsequent transformation are highly intense, and the geological conditions are exceedingly complex, no matter whether the deposits are endogenous, exogenous, or metamorphic. The complexity of boundary conditions of groundwater systems in karst mining areas with abundant water is mainly manifested in the irregularity of topographic watersheds, the multistage nature of erosion datum, the diversity and invisibility of genesis–tectonic types of geological boundary, and the variability of boundary hydrodynamic properties. The complexity of groundwater system structure is mainly manifested in the diversity and variability of karst aquifers, non-soluble rock aquifers (bodies), primary and secondary structural properties and their mutual relationship. The complexity of the properties of water-bearing media is mainly manifested in karst aquifers, which are not only strongly developed but also exhibit significant variability. This variability includes the direction, scale, density, and connectivity of karst caves, conduits and fissures. The characteristics of water richness, permeability, and hydraulic connections also display prominent anisotropy. The influence of mining engineering and mining activities on groundwater systems in mining areas is huge and far-reaching. In addition, the design of mine shafts, mining pits, and development engineering often requires real-time adjustments in response to changes in ore bodies and mining technical conditions during the mining process. The disturbances and impacts of mining engineering and activities on the water environment and groundwater systems are also difficult to predict accurately. These influences have increased the complexity of groundwater systems in mining areas to varying degrees. This paper systematically examines the complexity of groundwater systems in karst mining areas with abundant water. It provides a detail analysis of typical examples, along with a visual representation of the distinctive characteristics of these systems. This paper discusses the complexity of groundwater systems in mining areas with abundant water. It addresses the challenges encountered in hydrogeological exploration within mining areas. The discussion focuses on optimizing and adjusting the evaluation indices for the complexity of hydrogeological conditions as outlined in current specifications. Furthermore, it emphasizes the need for quantifying evaluation standards and establishing a reasonable assessment scale for the exploration control of complex hydrogeological conditions in mining areas. Besides, the paper offers recommendations for revising and improving the existing specifications.
Articles in press have been peer-reviewed and accepted, which are not yet assigned to volumes /issues, but are citable by Digital Object Identifier (DOI).
2024, 43(6): 1248-1260.
doi: 10.11932/karst20240603
2024, 43(6): 1275-1286.
doi: 10.11932/karst20240605
2024, 43(6): 1305-1316.
doi: 10.11932/karst20240608
Founded in 1982 bimonthly
ISSN: 1001-4810
CN 45-1157/P
Editor-in-chief: Jiang Zhongcheng
Sponsor: Chinese Academy of Geological Sciences
Sponsored by: Institute of Karst Geology, Chinese Academy of Geological Sciences
Cosponsor: International Research Center on Karst under the Auspices of UNESCOKarst Geology Committee of Geological Society of ChinaSpeleology Committee of Geological Society of China
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