Demonstration of groundwater development and utilization in southwest karst area

1. Introduction to achievements

This project is a "hydrogeologic environmental geological survey and demonstration of groundwater development and utilization in southwest karst areas" deployed by China Geological Survey since 1999. It is jointly implemented by Institute of Karst Geology of Chinese Academy of Geological Sciences and Geological Survey Institutes of eight southwest provinces (autonomous regions and municipalities). Taking the karst basin as a unit, the project carried out a comprehensive hydrogeological and environmental geological survey of1∶ 50,000, grasped the karst drought, flood and rocky desertification, and put forward the karst water development project scheme and the comprehensive improvement division of the basin geological environment; Select typical karst water sources for groundwater development and demonstration of comprehensive management of ecological environment; Comprehensive research on groundwater and environmental geology in southwest karst areas will provide basic geological data and countermeasures for solving drought and water shortage in southern karst areas and promoting comprehensive management of rocky desertification, and provide geological scientific basis and technical support for new rural construction in southern karst areas. Completed1∶ 50,000 hydrogeological survey with an area of 200,000 square kilometers, hydrogeological drilling of 52,000 meters, comprehensive geophysical exploration of 60,000 points and karst cave exploration of 60 kilometers. According to the development conditions of different types of areas, according to local conditions, the development and utilization of karst groundwater and the demonstration of comprehensive management of ecological environment are carried out by means of plugging holes and storing water, intercepting underground rivers, returning water from large springs, drilling wells, drilling large wells and inclined wells.

2. Basic principles

Through investigation and detection, the groundwater distribution structure, water circulation mechanism, water pollution, ecological environment and development, utilization and protection of different karst environment types are found out. Through monitoring and testing, the formation and evolution law and dynamic change trend of karst water system are mastered. Through scientific and technological research, the water quality, water quantity and development and utilization potential are evaluated, and the zoning of groundwater development and utilization, water pollution prevention and comprehensive improvement of ecological environment is formulated; Through the demonstration of development and management, the optimization model of effective development, utilization and protection of karst water resources is established, which has accumulated experience for surface promotion.

3. Technical characteristics

(1) The underground river (Daquan) water supply demonstration project adopts the methods of diversion, lifting, blocking, storage and excavation to develop the underground river as the water supply source to solve the serious drought and water shortage problem.

(2) Drilling demonstration project, searching for water storage structure, combining exploration with production, drilling and water supply.

(3) The demonstration project of comprehensive improvement of ecological environment takes the surface water and groundwater system as a whole, and establishes an optimized model of effective development, utilization and protection of water resources through agricultural structure adjustment, soil erosion prevention, rocky desertification control and ecological restoration.

4. Technical indicators

The accuracy of regional hydrogeological environmental geological survey is1:50,000, and the accuracy of hydrogeological and engineering geological demonstration in the demonstration project area of groundwater development and utilization is1:110,000 to1:2000.

Second, the scope of application and application examples

1. Scope of application

Mainly used in southwest karst areas, including Yunnan, Guizhou, Guangxi, Hunan, Sichuan, Chongqing, Hubei and Guangdong, with a karst distribution area of 780,000 square kilometers. Serious drought and water shortage, serious soil erosion and karst rocky desertification, deterioration of groundwater quality, serious karst collapse and karst waterlogging in this area have restricted economic and social development.

2. Popularization, application and effect.

Six underground regulating reservoirs were formed by intercepting underground rivers, and more than 200 wells were drilled, which solved the drinking water problems of more than 6,543,800 people and irrigation water problems of more than 500,000 mu of cultivated land.

(1) In the karst peak forest plain area, the development and utilization of shallow groundwater promoted the construction of efficient agricultural bases for grain and vegetables, and achieved obvious economic benefits.

Xie cun Qiao Mei Demonstration Zone in Litang Town, Guangxi, developed groundwater in the surface karst system and built an efficient agricultural base with vegetables as the mainstay. The total output value of vegetables exceeded 654.38 million yuan, an increase of 20% ~ 30%. The output per unit area of radish has increased from 2,000 kg in the past to 3,500 ~ 3,500 ~ 5,000 kg now, with an annual output value of 2.35 million yuan, an increase of 6.5438+250,000 yuan, and per capita income.

(2) In karst peak-cluster depression, economic and ecological benefits have been achieved by developing and utilizing surface karst spring water and building economic and ecological forests.

In Sanzhiyang Demonstration Zone, Du 'an County, Guangxi Province, seven reservoirs were built in the valley where the surface karst spring and slope flow meet, and drip irrigation technology was used to meet the water demand of fruit trees and medicinal materials bases, and four types of ecological comprehensive construction areas were built. The average annual income of local residents has increased by more than 800 yuan.

A demonstration project of karst water development and ecological restoration of fruit surface layer was carried out in Pingguo County, Guangxi, and the key development demonstration was carried out by using high surface karst belt springs. Six 3,000-cubic-meter water tanks were built, and a tap water project was built near the village, ending the history that 278 households in Longhe and Miaoguan Natural Villages were short of water for generations. An irrigation system integrating sprinkler irrigation, drip irrigation and irrigation was installed to ensure high and stable yield of crops. Three-dimensional eco-agricultural model in peak-cluster karst area and intensive management demonstration base for early fruiting and high yield cultivation of famous fruit trees in rocky desertification area were established.

(3) In areas with severe drought and water shortage, the development and utilization of groundwater resources through underground rivers and motor wells have solved the problems of drinking water for residents and irrigation water for cultivated land, and achieved remarkable social and economic benefits.

A demonstration project of backwater development of Pijiazhai karst spring was built on the edge of Luxi Basin in Yunnan, with an allowable exploitation amount of 60,000 m3/d, which solved the drinking water problem of 25,660 people and the irrigation water problem of 36,000 mu of cultivated land.

In Guizhou province, the demonstration project of karst water development in Jumu underground river was implemented, and underground space was used to retain groundwater at the exit of underground river to form a reservoir. An underground reservoir with a storage capacity of 2.392 million cubic meters and a high-level reservoir with a storage capacity of 300 cubic meters were built, which solved the drinking water problem of more than/kloc-0.2 million people and/kloc-0.4 million large livestock in this area. The average income of rice increased by 1.50 kg/mu, the total income of rice increased by 900,000 kg/year, and the output of rape increased by 88,200 kg/year, achieving economic income of 1.45 million yuan/year.

In Bijie, Guizhou, by searching for favorable water-rich zones and carrying out hydrogeological drilling, 4 wells/kloc-0 were completed, and the water inflow was 4500 m3/d, which solved the drinking water source for more than 50,000 people and the irrigation water problem for more than 20,000 mu of dry land, and accumulated experience for the effective development and utilization of water resources in karst areas in southwest China.

3. Application prospect

In recent years, the precipitation in southwest China is generally less. For example, since February of 20 1 1 year, the precipitation in most parts of Yunnan Province is only 20 ~ 50 mm, and the precipitation in the central and northern regions is less than 20 ~ 50 mm, which is 50% to 80% less than that in the same period of normal years. The areas with severe drought are mainly karst areas, where tiankeng and karst pipelines are developed and rocky desertification is serious. Due to the development of karst and rocky desertification, the atmospheric precipitation is rapidly transferred underground, which leads to the shortage of surface water and the difficulty for residents to drink water in dry season, forming the phenomenon that "groundwater is rolling and surface water is as expensive as oil". At the same time, due to the relatively weak regional economy and insufficient water conservancy facilities, especially the lack of groundwater development projects in karst areas, the engineering water shortage situation has been caused.

Karst groundwater is of great significance for solving drinking water safety. There are a lot of natural water resources in karst areas in southwest China, but the utilization rate of existing development is low. The allowable exploitation of karst water resources is 61.400 million cubic meters/year. There are 2,763 recorded underground rivers, with a total length of 1.3493 km and a total flow of 1.440 m3/s (45.4 billion m3/year) in dry season, which is equivalent to a Yellow River. However, due to other reasons, the development and utilization rate of karst water resources is only 15%, which has great potential for development and utilization.

Third, promote the transformation model.

It mainly includes: publicity and reporting, conference exchange, personnel training, technical consultation, on-site service and technology transfer.

Technical support unit: Institute of Karst Geology, Chinese Academy of Geological Sciences

Contact: Wang Shen Xiariyuan

Mailing address: No.50 Qixing Road, Guilin, Guangxi.

Postal code: 54 1004

Tel:13517731392 0773-5812942.

E-mail: tingw567 @126.com.