Karst spring cessation and flow attenuation

1. The flow of karst springs has stopped

According to incomplete statistics, more than 30% (46) of the large springs in the north have stopped or are close to stopping (Figure 5-1; Photo 5 -1 to photo 5-21). Among the 36 springs in Shandong with a flow rate greater than 10,000 m3/d, 6 were cut off in the early 1980s, and the current number is 16.

The four major spring groups in Jinan, Shandong Province, stopped flowing almost every year in the 30 years after Baotu Spring stopped flowing for the first time in 1972. Among them, from March 2, 1999 to September 17, 2001, The flow was cut off for 926 days.

The original flow of Shanxi Jinci Spring was 1.94m3/s, and it completely stopped flowing on April 30, 1994.

The original flow rate of Baiquan in Huixian County, Henan Province is 2.32m3/s. Since 1979, Baiquan has been in an intermittent flow state and has not returned in 2006.

The Wuhaila Monk Temple Spring in Inner Mongolia had an original flow of 108L/s and stopped flowing in 1984.

Xingtai Baiquan, with an original flow rate of 7 to 8 m3/s, began to stop flowing in 1982 and completely stopped flowing in 2006.

Beijing Yuquan Mountain Spring stopped flowing in 1974.

Hongshan Spring in Shanxi has an original flow of 1.0~1.5m3/s and stopped flowing in 2010.

Shanxi Lancun Spring had an original flow of 3.0~4.30m3/s and stopped flowing after 1986.

The original flow of Jiuli Mountain Spring in Henan was 9m3/s, and it completely stopped flowing after 1977.

The original flow of Heilongdong Spring in Hebei Province is 6 to 15m3/s, and the flow stopped intermittently after 1988.

There are more than 60 original springs in Guozhuang Spring, Shanxi Province, but now almost all of them have disappeared.

The Xiliu Spring of Xin'an Spring in Shanxi Province stopped flowing in the early 20th century, and the Nanliu Spring stopped flowing in the early summer of 2011.

The main karst springs with no flow in the north are shown in Table 5-1.

2. Spring flow attenuation

In the past 30 years, the flow of 80% of the northern karst springs has experienced a substantial and sustained decline. Figure 5-2 shows the flow curves of 15 karst springs in Shanxi with flow records. The total flow rate in the two periods from 1956 to 1979 and 1980 to 2008 decreased from 73m3/s to 46m3/s, and in 2008 it was only 34.84m3/s, less than 50% of the early flow rate.

Figure 5-1 Hydrogeological sketch of karst environment in northern China

Photo 5-1 Shanxi Hongshan Spring in 1986 (left), 2005 (right)

Photo 5-2 Shanxi Lancun Spring in 1986 (left), 2005 (right)

Photo 5-3 Shanxi Jinci Spring in 1986 (left), 2005 (middle, the water flow is artificially pumped), Pingquan Artesian Well in 1986 (right)

Photo 5-4 Shanxi Niangziguan Spring in 1986 (left), 2005 (right, artificial pumping)

Photo 5-5 Shanxi in 2005 The original site of Xiliu Spring in Xin'an

Photo 5-6 Luquan, Dongping, Shandong (2009)

Photo 5-7 Jingquan, Tengzhou, Shandong (2009)

Photo 5-8 Guoniang Spring in Laiwu, Shandong (2009)

Photo 5-9 Liangcheng Spring in Weishan, Shandong (2009)

Photo 5-10 Shili Spring in Zaozhuang, Shandong ( 2009)

Photo 5-11 Fengshui Spring, Zibo, Shandong (2009)

Photo 5-12 Baiquan, Huixian, Henan (2010)

Photo 5-13 Heilongdong Spring in Fengfeng, Hebei Province (2010)

Photo 5-14 Chaohua Spring in Mi County, Henan Province (2008)

Photo 5-15 Jiuli Mountain Spring in Jiaozuo, Henan Province (2008) Year)

Photo 5-16 Yimu Spring in Baoding, Hebei (2008)

Photo 5-17 Gudui Spring in Yuncheng, Shanxi (2008)

Photo 5-18 Hundred Springs in Xingtai, Hebei (2008)

Photo 5-19 Shigu Spring in Lincheng, Hebei (2008)

Photo 5-20 Ten Thousand Buddhas Spring in Beijing (2010) Year)

Photo 5-21 Lansengmiao Spring in Inner Mongolia (2001)

Table 5-1 Summary of administrative regions of dry (nearly dry) and intermittent dry springs in northern China< /p>

Figure 5-2 Dynamic curve of total flow of 15 karst springs in Shanxi

Before 1990, the average flow of the spring water in Pearl Spring in Henan was 1.46m3/s. After 1991, due to artificial mining, The surge in water volume caused the spring water flow to drop sharply to 0.61m3/s, and flow interruptions often occurred during the dry season (Figure 5-3).

The long series of observation data of Xiaonanhai Spring in Henan also show a declining trend. The average flow rate of the spring in the 10 years from 1966 to 1976 was 7.5m3/s; the average flow rate from 1977 to 1989 was 5.51m3. /s; the average flow rate of the spring from 1990 to 1999 was 4.45m3/s; the average flow rate from 2000 to 2002 was 4m3/s. Especially in the spring and summer of 2000, the flow rate dropped to 1.95m3/s (Figure 5-4).

Figure 5-3 Dynamic water flow curve of Pearl Spring in Henan Province

Figure 5-4 Dynamic water flow curve of Xiaonanhai Spring in Henan Province

Zhangqiu Ming Spring in Shandong Province, The average flow rate reached 3.99m3/s before the 1970s, and began to decline in the 1980s. In the late 1990s, due to large amounts of water inrush from mining, especially coal mines, the flow rate dropped sharply to less than 1.00m3/s. Among them, in April 1983 and 1984 The flow was cut off in April 2007, May 1987, April 1989 to June 1990, April to May 1993, and July 1999 to August 2003. The continuous flow cutoff time gradually lengthened (Figure 5-5 ).

Figure 5-5 Dynamic curve of spring flow in Zhangqiu Mingshui Spring, Shandong

The flow change characteristics of Heilongdong Spring in Hebei can be divided into three periods (Figure 5-6), in the 1980s In the past, due to the small amount of artificial mining, it was basically a natural change and was greatly affected by precipitation.

Figure 5-6 Dynamic curve of spring water flow in Hebei Heilongdong Spring

In the 1980s, due to the impact of artificial mining and coal mining drainage, the spring flow rate declined rapidly, and the spring flow rate dropped from 6.98m3 /s dropped to 2.21m3/s, a decrease of 4.87m3/s, a relative reduction of 68%.