| 基于表层岩溶带调控的峰丛洼地低影响开发构建 |
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| 引用本文： | 姜光辉,刘凡,王奇岗,郭芳.基于表层岩溶带调控的峰丛洼地低影响开发构建[J].中国岩溶,2022,41(2):165-173. |
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| 作者姓名： | 姜光辉 刘凡 王奇岗 郭芳 |
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| 作者单位： | 中国地质科学院岩溶地质研究所/自然资源部、广西岩溶动力学重点实验室，广西 桂林 541004 |
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| 基金项目： | 广西重点研发计划(桂科AB18221093)；国家自然科学基金(42172287)；桂林市科学研究与技术开发计划（20180101-2） |
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| 摘 要： | 岩溶峰丛洼地地区石漠化、饮水困难和水污染等环境问题高发，生态环境十分脆弱。低影响开发概念的引入有助于规范开发行为，促进水资源的高效利用，降低石漠化和地下河污染风险。根据水文条件和开发方式岩溶洼地空间分为坡耕地水土流失敏感区、表层岩溶泉水源地敏感区和落水洞污染输入敏感区。低影响开发模式总体是在3类敏感区实现5个管理目标。坡耕地敏感区的低影响开发目标设置为降低农田耗水量和减少水土流失，开发途径是减少蒸发和调控坡面洪水径流。表层岩溶泉敏感区的管理目标是降雨－径流资源化利用和饮用水安全保障，通过实施雨水收集回用工程和设置水源地保护区来实现。落水洞敏感区需要通过设置径流缓冲区和沉淀过滤池来预防污染物进入。我国南方石漠化地区探索和总结出以表层岩溶带降雨－径流管理为特征的低影响开发模式。该模式要求峰丛顶部留置生态保护区涵养水源。岩溶洼地底部为落水洞排洪预留缓冲区，利用岩溶裂缝设置下凹式绿地，实现自然渗透和净化。“峰”、“洼”之间过渡区划定水源地保护区边界，同时设法增加雨水资源化利用率，补充生态和生活缺水量。低影响开发模式也适用于峰丛洼地发育的东南亚和中美洲等地区。
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| 关 键 词： | 低影响开发 集雨 石漠化治理 降雨补给 水柜 |
| 收稿时间： | 2021-06-13 |
Low Impact Development construction of peak cluster depression based on regulation of epikarst zone |
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| Institution: | Institute of Karst Geology, CAGS/Key Laboratory of Karst Dynamics, MNR&GZAR, Guilin, Guangxi 541004,China |
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| Abstract: | Most of the bare karst areas environments with the widest distribution in southern China have peak cluster depression landforms. With high incidence of many environmental problems such as rocky desertification, flood, water shortage, and water pollution, the karst environment there is proved to be very fragile. For the bare karst environment, it has a very developed subterranean river drainage networks, causing most of the water resources to enter the aquifer, and then flow and discharge rapidly through the underground karst conduits. For a long time, as a karst living environment, the lack of water and soil resources have become the main cause of environmental degradation.The introduction of the concept of Low Impact Development (LID) is necessary and timely in the karst peak-cluster depression area, based the rich research and practice in southern China. It is believed to be effective for promoting the utilization of water resources, reducing human disturbance, and covering the other environmental problems, such as rocky desertification and risk of underground river pollution. The LID methods based on the regulation of the epikarst zone and sinkholes are mainly suitable for guiding the development of karst land in dolines and depressions. It is realized by solving the questions of how to plan the land use and to design the rural infrastructure according to the special hydrogeological conditions and epikarst hydrological process. The concept and technology of LID in view of urban facilities will give guidance for the construction of a holistic environmental remediation project in a rural area, including water resources storage, pollutant treatment, and land restoration for rocky desertification. It is very helpful to promote rural revitalization in the remote and fragile ecological environment area of karst rocky mountains. Karst dolines naturally have topographic and hydrogeological conditions that promote rapid rainfall infiltration. Controlled by monsoon climate, the karst environment is characterized by distinct rainy season and dry season. Due to the lack of soil cover, storm water forms various types of runoff on the rocky slope, which flows into the underground river eventually through epikarst zone and sinkholes. The epikarst zone with a high degree of karstification has high hydraulic conductivity and regulation and storage function with a large number of small caves. It is the main water storage space on the slope and forms the epikarst spring. The bottom of the depression is flat with continuous soil cover. The flood is discharged by the sinkhole, but sometimes the groundwater inversely enters the karst depression through the sinkhole, resulting in waterlogging. Karst depressions are widely used as living space and agricultural planting. According to its terrains, development practice and disturbance intensity, the land of karst doline can be divided into three kinds of sensitive areas, and they are, (1) sloping farmland with risk of soil erosion, (2) epikarst springs for drinking water source with risk of pollution, and (3) the sinkholes with risk of contaminant input. The LID model would try to achieve five management goals in the three sensitive areas.(1) The goal of LID in the sloping farmland is to minimize water consumption by crop irrigation and to protect precious and thin soil from erosion, which technically can be achieved by requiring a filtering system such as building terraced fields, interception basin and straw mulching, so as to regulate soil moisture and slope flood runoff. (2) The management goals of the sensitive areas of epikarst springs are the utilization of rainfall-runoff resources and the ensurence of drinking water safety, which technically can be achieved by implementing rainwater harvesting projects and setting up water source protection area. (3) Contaminant interception and absorption facilities, such as buffer zone and sedimentation and filtration ditch, should be built in the sensitive area of sinkhole for achieving the goal of stopping contaminants entering groundwater. The LID model for peak cluster, or “LID based on epikarst”, which is characterized by rainfall -runoff management in the epikarst zone, has been explored and summarized in the karst rocky desertification region of South China. The model requires reserving the water resources in the woodland area at the top of the peak in the process of development planning and utilization of karst depression, for enhancing the recharge by infiltration through epikarst zone. In the intensive utilization of land at the bottom of karst dolines, the buffer zone would be reserved for controlling flood discharge by sinkholes, and a low elevation green belt is set with filled karst grooves for promoting natural infiltration and purification. In the transition zone between “peak” and “doline”, the scope and boundary conditions of water confluence at epikarst spring should be clearly defined, and the boundary of the water source protection zone should be determined. At the same time, it is necessary to increase the utilization of rainwater to supplement the water shortage of ecosystems and living. Although LID model based on epikarst is raised from the rocky desertification control in southern China, it could be possibly extend to the karst areas in other regions such as Southeast Asia, where peak-cluster is also well developed. |
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