Karst water and its function

There are 685,000 km2 carbonate rocks in the North China Platform of China, covering 13 provinces, autonomous regions and municipalities (Figure 2- 1), and there are abundant karst groundwater. According to the statistical calculation of karst water resources evaluation results in recent years, the total natural resources in the whole region are 65.438+0.088 billion m3/a, and these karst groundwater basically circulate with relatively independent recharge, diameter, storage and discharge, forming a series of large-scale karst spring water resources systems. Karst spring is the most important natural discharge mode of water resources in this system. According to statistics, there are more than 200 springs with important water supply significance in the whole region, among which the springs with natural displacement greater than 170 have more than 100L/s (Figure 2-3).

Second, the function of karst water

Karst groundwater in the north has the characteristics of high concentration, dynamic stability and good water quality, which not only becomes an important local water supply source, but also many springs become important tourism resources because of their rich historical and cultural connotation and unique natural landscape.

1. Water supply function

Karst groundwater has become the drinking water source for people and animals in more than 30 large and medium-sized cities in northern China, such as Taiyuan and Jinan, 100 county-level cities and vast rural areas in karst mountainous areas (Figure 3-1); It is the cooling water of dozens of large and medium-sized thermal power plants in the north. For example, Shentou Power Plant, Yangcheng Power Plant, Yangquan No.2 Power Plant, Pucheng Power Plant, Hequ Power Plant, Jiaozuo Power Plant, Datang Huaibei Power Plant, Shandong Zouxian Power Plant, Shi Heng Power Plant, etc., the installed capacity of thermal power in Shanxi Province alone exceeds 20 million kW·h, and karst groundwater is also the main water supply source for life and production of more than 70% large coal mines in northern China.

2. Agricultural irrigation

Tens of millions of acres of farmland in the north rely on karst groundwater for irrigation. The corresponding main irrigation projects include Hongshan Irrigation District, Longzici Qiyi Irrigation District, Niangziguan Quanmianhe Irrigation District, Xin 'an Spring Hongqi Canal Irrigation District, Heilongdong Yu Quan Fuyang River Irrigation District, Sanguquan Qingtianhe Reservoir, Huixian Bai Quan Irrigation District, Shaizhudong Jing Quan Qu Hui Irrigation District, Zhangqiu Mingshui Spring Xiuhui Irrigation District, Xingtai Bai Quan Irrigation District, Hebei Province, etc.

3. Tourism function

Many karst springs in the north are also important cultural and tourism resources. Taiyuan Jinci, Jinan Baotu Spring and Huixian Baiquan are famous tourist attractions at home and abroad, with touching legends and profound cultural connotations. Huoquan, Hongshan Spring, Shuishentang Spring, Leiming Temple Spring, Niangziguan Spring, Shaanxi Zhougongmiao Spring, Lingquan, Henan Xiaonanhai Spring, Pearl Spring, Inner Mongolia Lasengmiao Spring, Ningxia Miaoshan Lake Spring, Zhangqiu Baimai Spring, Laolongwan Spring, Sishui Spring and Zibo Spring all have high tourism value, and the world geopark Yuntaishan Double-headed Spring has brought infinite vitality to the scenic spot. In addition, some rivers with the significance of mother river originate from karst springs, such as Fenhe River in Shanxi Province originated from Leimingsi Spring in ningwu county; Hutuo River originated in Ma Quan, and was replenished by Shangping Spring, Niangziguan Spring and Weizhou Spring in Hebei along the way. Juma River, listed as a world geological park, originated from Laiyuan Spring in Hebei Province. Sanggan River, the main tributary of the Yongding River in the capital, originated from Shentou Spring in Shuozhou, Shanxi.

Figure 3- 1 Distribution Map of Main Karst Water Supply Cities and Water Sources in Northern China

4. Ecological function

Karst spring water not only maintains the specific ecological environment in Quankou area, but also is a necessary factor to maintain the benign ecological environment along the downstream coast in the arid, semi-arid and severely uneven distribution of precipitation in the north. Lingquan is exposed in Heyang Wetland Nature Reserve, Shaanxi Province, the largest natural lake and wetland reserve in China. The wide water surface and dense reeds provide a good natural home for birds to inhabit and survive, and become a big stop for 135 migratory birds to migrate for the winter. Baiquanquan Wetland around Xingtai Ancient City, together with Zehu Wetland and Fuyang River Wetland on the mainland, forms the largest wetland in the Central Plains, covering an area of more than 400 square kilometers. The special ecosystem function provides drinking fresh water, plant protein, biological protein and living materials for local people's lives. In times of economic difficulties, it is a lifeline to feed the local people.

In a word, karst groundwater plays an important role in industrial and agricultural production, people's life, ecological environment improvement and cultural undertakings in northern China, especially in the construction of high-speed energy bases in northern China over the past 30 years of reform and opening up.