Karst water system (spring area) in the southeast section of Taihang Mountain
Fig. 44 Karst hydrogeological map of the south side of Taihang Mountain (1: 1 10,000)
1-karst area on the south side of Taihang Mountain; 2- karst spring (> 1m3/s), 3- karst Koizumi (
I. Xin 'an Spring Karst Spring Area
I. System boundary
This spring area is located in Changzhi, Shanxi Province. The spring water is exposed in the riverbed of Zhang Zhuo, which is located in the west wing of anticlinorium in Taihang Mountain. It is a monoclinic water storage structure inclined to the west. The eastern boundary is the lower CAMBRIAN aquifuge; The south boundary is the underground watershed in Zhaozhuang-Zhang Shu area; The western boundary is the surface watershed; Heshun-Boli in the north is an underground watershed. In the system, the exposed area of carbonate rocks is 2 189km2, the concealed area is 10524km2, and the area of non-carbonate rocks is15km2, totaling 12828km2.
2. Hydrogeological characteristics
The main aquifer groups are Middle Cambrian and Middle Ordovician. The Middle Cambrian is dominated by oolitic limestone, which is 250m thick and rich in water, and is the main recharge layer of lime spring group in this karst water system. Middle Ordovician limestone is 590 meters thick and rich in water, which is the main recharge layer of Wangququan Group. The unit water inflow is 7.81~ 85.11l/s m, and the water yield of a single well is generally 1000 ~ 2000 m3/d, with a maximum of 5000mm3/d.
Precipitation infiltration is the main recharge source of karst water, accounting for about 80% of the total recharge; River leakage recharge is the second, accounting for about 20%. The main leakage section is Jiaojiao Village, Zhangzhuohe River. According to the observation data of 1982 ~ 1983, the leakage is 2. 16m3/s, and the runoff direction of karst water is controlled by the water storage structure. In the northern part of the system, karst water first moves from northeast to southwest along the stratigraphic strike, and then turns to east-west in Lucheng area. In the southern half of the system, karst water mainly migrates from southwest to northeast or from south to north, and finally collects in the spring mouth for discharge. Xin 'an Spring is exposed in Zhang Zhuo Valley, which is a contact overflow spring (Figure 45).
Fig. 45 Hydrogeological Profile of Xin 'an Spring
1-gravel; 2- Loess; 3- limestone; 4- Leopard limestone; 5- dolomite; 6- oolitic limestone: 7- bamboo-leaf limestone; 8-breccia marl; 9— Shale; 10-timely sandstone; 1 1- failure; 12- drilling; 13- spring; 14- water level elevation
There are two strong runoff zones, one is Changzhi-Weizi Town-Xin 'an Spring, and the other is Zuo Quan-Xijing-Licheng-Xin 'an Spring.
The chemical types of karst water are HCO 3- calcium type to HCO 3- sulfuric acid-calcium magnesium type, and the salinity is 0.3 ~ 0.46 g/L.
Xin' an Spring belongs to a stable karst spring, with maximum discharge 16.3m3/s, minimum discharge 10. 1m3/s, multi-year average1.25m3/s and multi-year average instability coefficient1. There is a positive correlation between spring discharge and precipitation, and the dynamic change in the year is one peak and one valley. The peak value appears in10 ~1February, and the trough appears in May-June, and the rainfall lags behind in March-June.
Due to the large-scale exploitation of karst groundwater and coal mine drainage, the flow of spring water is decreasing continuously, and the current flow of spring water is less than 4m3/s.
Second, Sanguquan karst spring area
1. Spring boundary
Sanguquan karst spring area is located in the southeast edge of Shanxi Plateau in Jincheng area, Shanxi Province. The spring water is exposed in Danhe Gorge, and the geological structure belongs to the southeast wing of Qinshui syncline. The stratum generally inclines to the north or northwest, which is a monoclinal water storage structure. The eastern boundary is the surface-underground watershed, with the fire line-horse circle as the boundary; The southern boundary is the weak permeable layer of Upper Cambrian and Lower Ordovician; The northern part of the western boundary is Gaoping-Jincheng fault fold belt, and the northern boundary is the surface watershed. The exposed area of carbonate rocks in the system is 1 1 12.0km2, and the concealed area is 2227.5km2, with a total area of 3339.5km2.
2. Hydrogeological characteristics
The aquifer formation is Majiagou Formation of Middle Ordovician and Middle Cambrian strata. Majiagou Formation is composed of thick layered limestone and dolomitic limestone, with a total thickness of 400m, the thickness of Majiagou in the main water-bearing section is 50 ~ 200 m, and the thickness of Xiamajiagou is 40 ~120 m. Aquifers are distributed in the east and south of the system, and karst fractures are developed. The unit water inflow is 0.65 ~ 5l/s m, and the maximum water inflow can reach15 ~ 23l/s m. The Middle Cambrian is distributed in deep valleys in the southeast, with thick oolitic limestone and bamboo-leaf limestone, and karst fractures develop, from which three springs flow out. The main recharge source is the leakage recharge of Ordovician aquifer.
The source of groundwater recharge in Ordovician aquifer is mainly atmospheric precipitation, followed by surface water leakage. Surface water leakage includes leakage from the lower reaches of Danhe River flowing through limestone and leakage from small and medium-sized reservoirs built in limestone distribution area in this area. The karst water flows to the north, northeast, south and southwest, and turns to the southeast after reaching Jincheng. The discharge of karst water is controlled by structure and regional erosion datum. The Danhe River is deep in the soluble rock stratum, which makes the groundwater overflow into springs at different layers (Figure 46), which is an erosion overflow spring. The discharge is mainly spring discharge, followed by undercurrent.
Fig. 46 Hydrogeological Profile of Sangu Spring Area
The quality of karst water belongs to calcium bicarbonate type and HCO calcium magnesium sulfate type, and the salinity is 0.28 ~ 0.9g/L.
The annual average total flow in the spring area is 7.2m3/s, and the dynamic change of karst water is closely related to precipitation. With the arrival of the rainy season, the water level changes from June to 10 every year, with a monthly amplitude of1.36m. After 10, the water level drops by 0. 15m. The same is true of the change of spring flow. For example, the average precipitation of 1963 ~ 1964 is 8 18mm, which is 27.4% higher than the average precipitation of the system for many years (642 mm). The maximum spring flow is 1 1. 1.3 m3/s and 1.2 m3/s respectively. Another example is that the precipitation in 1978 is 467. 1mm, which is 26.7% lower than the average precipitation for many years. 1979 The spring flow decreased to 6.24m3/s, which was lower than the average for many years 18.5%.
Due to the large-scale exploitation of karst water and coal mine drainage, the groundwater level has dropped by more than 30 meters, and the spring flow has dropped to about 3 cubic meters per second. ..
3. Dongfeng Lake Spring Karst Spring Area
Dongfeng Fengquan karst spring area is located at the junction of Hebei and Shanxi provinces, including most of Shexian county and some areas of Licheng. Its northern boundary is Fushan igneous body and the surface watershed in the western section; The eastern boundary is the water-blocking boundary of Shexian-Changting fault; The south boundary is the underground watershed of Dongyang Pass and Pingtou Line; The southern and northern sections of the western boundary are faults, and the middle section is composed of lower CAMBRIAN shale. The area is 69 1km2, of which the exposed carbonate rock area is 584km2 and the concealed carbonate rock area is 90km2.
This area is located in Taihang Mountain area, with the surrounding elevation of 700 ~ 1000 meters, the basin area of 1300 ~ 1400 meters, and the basin elevation of about 500 meters, belonging to an intermountain basin. Qingzhang River flows through this area, with an average flow of 8.5m3/s for many years and 0.35m3/s in dry season. It leaked into Shexian basin, and local river sections were cut off in dry season. The annual average precipitation is 572.9mm, the annual evaporation is 1200 ~ 2000 mm, and the average temperature is 12 ~ 14℃.
The system is located in Shexian fault basin on the east side of the middle section of Taihang Mountain fault uplift belt, with developed faults. The Shexian fault has a fault distance of 800 meters, which makes the limestone in this area contact with Proterozoic strata. The exposed stratum is the Lower Paleozoic stratum.
Lower Paleozoic carbonate rock is the main karst aquifer of the system, and the middle Ordovician limestone aquifer is composed of pure limestone, leopard limestone and breccia limestone, with a thickness of 200m, and karst fractures are developed, mainly karst fractures and dissolved pores, followed by karst caves, which are rich in water. Single well water yield 1200 ~ 1680m3/d, the middle-upper CAMBRIAN is distributed in the north and west of the system, with a thickness of 220m, and is mainly composed of oolitic limestone, argillaceous banded limestone and bamboo-like limestone, with developed fracture karst and medium water yield, and spring flow100 ~ 300.
Precipitation and river infiltration are the main recharge sources of karst water, and limestone is exposed in a large area in the area, and precipitation infiltration recharge accounts for the vast majority of the system recharge. When Qingzhang River enters Shexian Basin, it leaks, with the leakage amount of 18606200 m3/a ... Karst water flows from all directions to Dongfeng Lake Spring in Shexian County, and overflows into a spring due to the water blocking effect of Shexian fault, which is a fault overflow spring. Part of Quaternary pore water overflows the surface through Quaternary replenishment along the bed of Qingzhang River. Karst water is calcium bicarbonate and calcium magnesium bicarbonate type water, with salinity of 0.24 ~ 0.3 1g/L and pH value of 6.8 ~ 7.7.
Dongfeng lake spring system is a completely drained karst water system. Most of the karst water is discharged by Hufeng Spring in Shandong, and a small part is replenished by Quaternary pore water and discharged into Qingzhang River, so the spring flow basically represents the natural resources of the system. According to the observation in 1960s, the flow of this spring is 1.67 ~ 2.08m3/s, which is relatively stable.
Fourthly, the karst spring area of Heilongdong Spring.
The karst spring area of Heilongdong Spring is located in the west of Handan City, Hebei Province, including parts of Handan City, Shexian County, Wu 'an City and Cixian County. The eastern part of its northern boundary is the watershed between igneous rock and groundwater; The western section is a water-resisting boundary composed of lower CAMBRIAN shale and Proterozoic strata; The eastern boundary is the buried depth line of Ordovician limestone roof1000 m; The eastern part of the southern boundary is the underground watershed between Lizhen and the eastern part, and the western part is the underground watershed of Laoyeshan anticline. The western boundary is Shexian-Changting fault. It covers an area of 2074km2, of which the exposed limestone area 1207km2.
The system is located in the hilly area of Taihang Mountain in the west and North China Plain in the east, with an altitude of 200 ~ 1000 meters ... The rivers in the area include Nanming River, Fuyang River and Zhanghe River, all of which belong to Haihe River system. Nanming River is a seasonal river, which causes leakage in limestone areas. The source of Fuyang River is Heilongdong Spring, with an average flow of 6 ~ 9 m3/s for many years. Zhanghe River flows through the southern edge of the system, which has a certain recharge effect on karst water. The climate is semi-arid and semi-humid, with annual average precipitation of 574.7mm, evaporation 1882.3mm and average temperature 13.05438+0℃.
This area is located in the east of the middle section of Taihang Mountain fault uplift belt, and consists of a series of NE-trending horsts and grabens. Paleozoic strata are widely distributed, and the surface of Hecun basin and the eastern part of Gushan is covered with Quaternary loose sediments.
Cambrian-Ordovician carbonate rocks are the main karst aquifers in this system. The middle-upper CAMBRIAN aquifer is distributed in the west and southwest, and consists of oolitic limestone and bamboo-leaf limestone, with a thickness of 3 15m. Fracture karst is developed, and karst caves are developed along argillaceous limestone and shale at the bottom, with spring flow rate 16.7 L/s and medium water abundance. The Middle Ordovician karst aquifer is distributed in the east of the system, and consists of medium-thick layered limestone, porphyritic limestone and breccia limestone, with a thickness of 545m m. Karst fractures are developed, mainly dissolved fractures, followed by karst caves, with strong water yield, and the water yield of a single well is generally1000 ~ 3000m3/d.
Precipitation infiltration and river leakage are the main recharge sources of karst water in this area, and the vast limestone exposed area in the west is the recharge area. The general flow direction of karst water is from west to east, and it mainly flows along the strong runoff zone when it enters the runoff zone. There are three strong runoff zones in the area, namely Cuilu-Bart-Sufeng strong runoff zone in the northwest, Suo Jing-Zhangerzhuang-Sufeng strong runoff zone in the west and Gangziyao-Shangzhuang-Peng Qiang runoff zone in the south. The above three strong runoff zones converge in Yangjiaopu area and flow to Heilongdong Spring Group to overflow the surface (Figure 47). Spring flow is affected by precipitation, and the flow in rainy season is generally11~15m3/s; In the dry season, the flow rate decreases, generally 6 ~ 9m3/s, and the maximum flow rate is 33.5 m3/s. In recent years, due to the increase of karst water exploitation in the system, the flow rate of spring water decreases, which stopped in April of 1988 and flowed out after heavy rain in August of the same year. It has basically dried up.
Fig. 47 Schematic diagram of formation conditions of Heilongdong spring group
The hydrochemical characteristics of karst water have horizontal and vertical zonation. The recharge area is HCO3-Ca HCO3-Ca Mg type water with salinity of 0.3 ~ 0.4g/L, and the runoff area and discharge area are HCO3 SO4-Ca type water and HCO3-Ca Mg type water with salinity of 0.6 ~ 0.8g/L, with local SO4-. With the increase of buried depth of limestone, the hydrochemical types often transition to SO4 HCO3-Ca Mg or Cl SO4-Ca Mg water, and the salinity increases from 0.4g/L to 0.6g/L, and the buried depth in the east reaches 7g/L.. ..
Verb (abbreviation of verb) Pearl spring karst spring area
Pearl spring karst water spring area is located in the west of Anyang city, Henan province, and belongs to Linxian area. Its northern boundary is the underground watershed of Qianzai-Lixinzhuang line in the east and the Lower Cambrian shale in Zhanghe area in the west. The eastern boundary is Cecilia Yip-Miaokou fault; The southern boundary is Xiawan and Heshun underground watershed. The west boundary is Linxian fault. It covers an area of 544 square kilometers, including 289 square kilometers of exposed carbonate rocks.
This area is located at the eastern foot of the middle section of Taihang Mountain, bordering the North China Plain in the east, with high terrain in the west and low terrain in the east. The hills in the west and the ridges in the east are 90-300m above sea level. The Zhanghe River flows through the northern edge of the system and leaks in the limestone reach from Dagucheng to Dongtaicang. The annual average precipitation is 595 ~ 68 1.3mm, the evaporation is1548 ~1548 ~1987.3mm, and the annual average temperature is 12.58 ~ 13.6℃.
Structurally, it belongs to Taihang Mountain fault uplift zone, and there are a series of NE-trending faults and dense zones in the east. Paleozoic strata are distributed in the whole area, and the eastern part is covered by Quaternary sediments. The main karst aquifer in the area is lower Paleozoic carbonate rock, and the middle-upper Cambrian is exposed in the west, which is composed of oolitic limestone, argillaceous banded limestone and dolomite limestone. Fracture karst is developed, with medium water abundance. The water inflow of a single well is 240 ~ 1920m3/d, and the spring flow is 0.25 ~ 300L/s. Middle Ordovician limestone is distributed in the central and eastern parts, with a thickness of 521.1~ 608.3m..
Precipitation infiltration is the recharge source of karst water in this area, and Zhanghe River enters the northern edge of this area, which has certain recharge to groundwater. Karst water flows from northwest to southeast, forming strong runoff zones in Cecilia Yip-Pearl Spring and Leikou-Pearl Spring, and overflows into a spring in Shui Ye Town due to water blocking by faults (Figure 48). Spring flow is affected by precipitation. According to the observation of 1982, the spring flow in September was 5.9m3/s, and it dropped to 2.8m3/s on October 24th, and it was 11m3/s on October 26th the following year. At present, the flow is about 0.3 ~ 0.
Fig. 48 Schematic diagram of geological section of Pearl Spring
1-clayey silt in the slope flood loess; Permian sandstone shale with coal seam; 3- Carboniferous sandstone shale and limestone with coal seam; 4- Middle Ordovician limestone and breccia limestone are superimposed; 5- torsion fault; 6- Rising spring; 7— Flow direction of karst water
Intransitive verb xiaonanhai karst spring area
Xiaonanhai karst spring area is located in Linxian County, Henan Province. Its northern boundary is the underground watershed of Xiawan, Shicheng and Zhangwu reservoirs. The northern part of the eastern boundary is the Cecilia Yip-Miaokou fault, and the southern part is the underground watershed formed by the axis of Caowangshui-Shijiagou anticline. The south boundary is the underground watershed between Shijiagou and Nancaisang. The west boundary is Linxian fault. The area is 96 1km2, of which the exposed limestone area is 395km2.
The system is located at the eastern foot of Taihang Mountain, which belongs to hilly area, with an altitude of 400 ~ 600 meters. Located in Linxian Basin in the west, with an altitude of 280 ~ 380 m, Huan River and its tributary Taoyuan River pass through the middle of the system, with an average annual flow of 4. 1m3/s (Beilingyang Station). The Taoyuan River was seriously leaking and the river dried up. The average annual precipitation in Linxian County is 595.2mm, which is concentrated from July to September, accounting for more than 70% of the whole year. The annual average evaporation is 1548. 1 mm, and the average temperature is 12.58℃.
This area is located in the southeast of Taihang Mountain fault uplift, with Linxian fault basin in the west and NE-trending faults in the east, and NW-trending faults become the north-south boundary of the system, such as Heshun-Anyang fault and Hejian-Dongyao fault. Paleozoic strata are widely distributed in this area, and Linxian basin and eastern plain are covered by Quaternary. Middle Ordovician limestone is the main karst aquifer in this area, with a thickness of more than 500 meters. It is medium-thick limestone and leopard limestone, with developed karst and strong water content. The well completion rate in Linxian basin is high, and the unit water inflow is 2.09 L/s m. ..
The recharge sources of karst water are atmospheric precipitation and river leakage, and atmospheric precipitation mainly penetrates into karst water through bare limestone areas. The Quaternary in Linxian Basin is more than 200 meters thick, and there are clay layers in the lower part. After the precipitation enters the Quaternary, it is generally discharged into the valley, and then the river flows through the limestone area and leaks to replenish the groundwater. The leakage of limestone reach from Lingyang to Xiejiaping in Huanbei is 4m3/s, and the limestone reach of Taoyuan River is the main channel. Karst water flows from the recharge area to the strong runoff areas of zhang jia zhuang-Doumazhuang, Beilingyang-Tianxi Town and Qiaoxi-Majiacun respectively, and overflows into springs due to the barrier of coal measures strata (Figure 49). The annual average flow rate of spring water is 5.6m3/s, but the current flow rate has been greatly reduced to about 1.2m3/s, which belongs to HCO 3-Ca Mg type water with salinity of 0.28g/L, total hardness of 13.92 German degrees and pH value of 7.25.
Fig. 49 Schematic diagram of Xiaonanhaiquan geological section
1-clayey silt in the slope flood loess; 2- Neogene sandstone; 3- Carboniferous sandstone shale and limestone with coal seam; 4- Middle Ordovician limestone and breccia limestone; ⑤ diorite; 6. Torsional fault; 7- Lift spring group
Seven, Shimensi spring karst water system
This system is located in the south of Linxian County, Henan Province. Its northern boundary is Shijiagou and Nancaisang underground watershed, and its eastern boundary is Hekou and the top of Lower Ordovician strata in Qi Lin. Fengmenkou fault in the east and Lower Cambrian shale in the west of the southern boundary. The west boundary is Linxian fault. The area is 556km2, of which the exposed carbonate rock area is 357.5km2.
This area is located at the southern foot of Taihang Mountain, with high terrain in the west and low terrain in the east, and the land elevation in the west is 13 15m. There are a series of basins along Qihe River and its tributaries, such as Yuankang, Qi Lin and Dongyao basins, with an elevation of 280 ~ 400 meters. Qihe River and Zhejiang all pass through this area, and there are many leaks in the upper reaches. According to the data of the weather station in the earth circle, the average annual precipitation is 749.6438+0438+0mm.
Middle Ordovician limestone is distributed in the whole region and is the main karst aquifer in this area. The lithology is thick limestone, dolomite limestone and breccia limestone. Karst development, mainly karst caves and small caves. The unit water inflow of borehole in Yuankang basin is1.44 ~ 2.05l/s m.
The recharge sources of karst water are precipitation infiltration and river leakage. The reach above Qihe River is often in dry season, and the reach from He Zhe Hejian to Shimensi is often cut off, with a unit leakage of 7.78 L/s km. Karst water is collected from the recharge area to the Zhejiang River and Qihe River, forming a strong runoff zone along the river valley. From Hekou to Shimensi Spring, due to the barrier of lower Ordovician strata and the overflow of Qihe River, the annual average flow of the spring is 4.6 1m3/s, which belongs to HCO3-Ca Mg type water, with salinity of 0.23g/L, total hardness of 12.09 German degrees and PH value of 7.25. At present, the flow of spring water has been greatly reduced.
Eight, Xujiagou spring karst water system
Xujiagou spring karst water system is located in Hebi City, Henan Province, with Ordovician roof depth line 1000m in the northeast, Qingyangkou fault in the east, Dabaiyu-Xixiang Basin fault in the south and Cecilia Yip-Miaokou fault in the west. The southern section is an underground watershed along the axis of Caowangshui-Shijiagou anticline, with an area of 352.3km2, in which the exposed carbonate rock area is 150km2.
The area is located at the southern foot of Taihang Mountain, with high terrain in the southwest and low terrain in the northeast, with low mountains and hills in the west and sloping plains in front of the mountain in the east. Qihe River flows through the southern edge of the system, with the annual average flow of14.56m3/s. The climate belongs to continental semi-arid climate, with annual average precipitation of 659.5mm, evaporation of 2029.6mm and annual average temperature of 14.35℃.
The strata in this area are Paleozoic, and the plain area is covered with Quaternary sediments. Middle Ordovician is distributed in most areas, with exposed areas in the west and hidden areas in the east. Limestone karst development. The water yield of a single well in the strong runoff area is 959 ~ 4800 m3/d, while that in other areas is100 ~ 208.7 m3/d. ..
The recharge source of karst water is precipitation, and the limestone exposed in the west and northwest is the recharge area. The general flow direction of karst water is from northwest to southeast. A strong runoff zone is formed between Hebi and Xujiagou Spring. In Xujiagou spring area, Qingyangkou fault blocks water, Qihe River cuts down, and karst water overflows into a spring (Figure 50). The annual average flow rate of the spring is 1.25m3/s, and the spring water belongs to the type of calcium magnesium bicarbonate with salinity of 0.31g/L.
Fig. 50 Geological Profile of Xujiagou Spring
1-limestone: 2-sandstone; 3- shale; 4- 4 yuan; 5- Fault
Nine, Huixian Baiquan karst spring area
Baiquan Karst Spring Area in Huixian County is located in huixian city, Henan Province. Its northern boundary is Fengmenkou fault, its eastern boundary is Qingyangkou fault, its southern boundary is coal seam outcrop line, its western boundary is underground watershed in the north and fault in the south. Area 1032.3km2, of which the exposed limestone area is 444km2.
The area is located at the southern foot of Taihang Mountain, with high terrain in the north and low terrain in the south, low mountains in the north, hills in the middle and plains in the south of Huixian County, with an altitude of about 80m. The average annual precipitation is 648.6 ~ 700 mm, increasing from plain to mountainous area.
Structurally, it belongs to the southeast of Taihang Mountain fault uplift belt. A series of NE-trending and NNE-trending faults are distributed in the south zonal structural belt, and Baiquan is in the convergence position of broom structure (Figure 5 1). Archaean, Proterozoic, Paleozoic, Mesozoic and Cenozoic strata are developed in this area. The Paleozoic strata are widely distributed, and the Quaternary covers the south of Huixian County.
The karst aquifer in this area belongs to the lower part of Middle Cambrian and Middle Ordovician, and consists of oolitic limestone, limestone, dolomite limestone and breccia limestone. Karst fractures are developed, with strong water-abundance, and single well volume1000 ~ 5000m3/d; The Upper Cambrian consists of thin-medium thick argillaceous banded limestone and fine-grained dolomite limestone, with weak water output and single well volume less than1000 m3/d. ..
Figure 5 1 Baiquan Brush Structure Map
The recharge source of karst water is precipitation, and the limestone exposed in the north of the system is the recharge area. Groundwater flows from north to south to Baiquan in Huixian County, and karst water overflows into springs due to faults on the south side of Huixian County, as shown in Figure 52. Spring dynamics are affected by precipitation, and the variation coefficient of spring water over the years is 1.67 ~ 10.84, which lags behind precipitation for 2 ~ 3 months. Due to over-exploitation, it has now dried up.
Fig. 52 Hydrogeological Profile of Baiquan-Huixian County
Ten, jiuli mountain spring area
Jiuli Mountain Spring is located in Jiaozuo, Henan. The eastern part of its northern boundary is Chizhuang fault, and the western part is located in the surface watershed between Yu He and Zifanggou. The eastern boundary is the Ordovician roof depth line1000 m; The south boundary is Pangusi-Zhucun fault; The northern section of the western boundary is the surface watershed along Duohuo, Liushukou and Sanguquan, the middle section is the fault, and the southern section is the groundwater watershed. Area 1592km2, including exposed limestone area 1073km2 and concealed limestone area of 506km2.
The system is located at the southern foot of Taihang Mountain, and the terrain decreases from north to south. The northern part is Zhongshan District, with an altitude above 1000m; The middle part is low mountains and hills with an altitude of 300-800 meters; The southern part is the piedmont plain with an altitude of 140 ~ 180m. Zifanggou, Shanmen River and Xishi River source are located in the mountainous area of northwest plateau, which flows eastward into Weihe River. They all leak through limestone areas, and there is only temporary water flow during the flood. From the plain to the mountainous area, the precipitation increases. The average annual precipitation in Jiaozuo is 647.2 mm, the average annual precipitation in western and northern mountainous areas is 728 mm, the average annual evaporation is 2048.8 mm, and the average annual temperature is 65438 08℃.
This area is located at the southern end of Taihang Mountain fault uplift belt, the northern edge of East Qinling belt structure belt, and the front of reflex arc in the east wing of southeast Shanxi mountain structure. Fault structures are developed, mostly in east-west direction and north-northeast direction, forming a monoclinal graben-type horst structure descending from northwest to southeast. The strata strike northeast with dip angle10 ~ 20 (Figure 53). Except for the lack of upper Ordovician to lower Carboniferous deposits, they are distributed in other eras, among which Paleozoic strata are the most widely distributed.
Fig. 53 Hydrogeological Profile of Jiuli Mountain Spring Karst Water System
The karst aquifers in this area are mainly carbonate rocks of Middle Ordovician and Middle Cambrian. The middle Ordovician aquifer is 300 ~ 350 meters thick and consists of medium-thick limestone, leopard limestone and a small amount of dolomite limestone. The karst fracture rate is 2.36% ~ 3.67%, and it can reach 5.42% in the valley area, with an average unit water inflow of 33.45 L/s m. The Middle Cambrian aquifer is distributed in the northern piedmont area and consists of oolitic limestone, with a thickness of 200 ~ 244 m, moderate water inflow and a spring flow of 0.1~ 0.5m3.
The recharge of karst water is mainly precipitation infiltration, and the limestone exposed in the northwest is the recharge area, followed by river leakage. According to the observation at 1980, the unit leakage of Xishi River is 2m3/s km, and that of Shanmen River is 0.5m3/s km. The general flow direction of karst water is northwest to southeast. Due to the water blocking effect of east-west faults, strong long-distance flow zones are formed in limestone near faults, such as Zhucun, Fenghuangling fault and Fangzhuang fault. In the natural state, karst water is collected in Jiuli Mountain Spring, most of which is discharged in the form of springs, and some of it is replenished to the Quaternary, rushing to the depths.
The dynamics of karst water is affected by precipitation, and the water level changes synchronously with precipitation, with no obvious lag phenomenon. Every year, the water level rises from June to September, and the high water level appears from September to 10. After 10, the water level drops, and the lowest water level appears from May to June of the following year. After mine drainage, the water level showed a downward trend in a step-by-step manner.
Karst water is generally HCO 3- calcium magnesium type, and locally HCO3-SO4-calcium magnesium type, with salinity of 0.23 ~ 0.39 g/L, total hardness of 14 ~ 17.5 German degrees, pH value of 7. 1 ~ 7.8 and water temperature of 65438.
Under natural conditions, the karst water in the system is discharged by spring water and undercurrent, but due to a large number of coal mine drainage and extraction of karst water for water supply, karst water is mainly discharged by mine drainage and artificial mining, and the spring water has already dried up. Since 1950s, the karst water dynamics of this system are as follows:
(1)1954 ~1964 is the rainy season, with an average rainfall of 802 mm, the mine drainage increased from 0. 16m3/s to 2.6m3/s, the average minimum elevation of groundwater level was 96m, and the highest elevation was1/kl.
(2) 1965 ~ 1977 is a normal period, with an average rainfall of 700mm, the mine drainage increased from 3.0m3/s to 6.66m3/s, the groundwater level remained at about 87m, and the spring water was cut off, forming a NE-SW funnel until 1973 and/kloc-0.
(3) Continuous drought 1978 ~ 198 1 year. The precipitation in mountainous areas is only 400 mm, the mine displacement is 6.66 m3/s, the water inflow is 1 m3/s, and the groundwater level is reduced to 80 meters.
(4) 1982, the precipitation in mountainous areas increased to 770mm, the mine drainage increased from 7.5m3/s to 9.58m3/s, the groundwater level still rose rapidly to 93.5m elevation, and most of the falling funnels were filled.
(5) 1983 ~ 1987 suffered from continuous drought, with precipitation of 593.7mm, mine drainage maintained at 7.9 ~ 9.4m3/s, and self-prepared well water1.51~1.96m3/s.
It can be seen from the above that the karst water level of the system is in dynamic balance, and the recharge and discharge are basically balanced, and the total discharge is the natural resource of the whole system.
According to the observation data of 1986 and 1987 mining areas, the average total drainage is 313,345,600 m3/a, in which the average mine drainage is 266,987,700 m3/a (8.47 m3/s) and the output of industrial self-prepared wells is 6.357,900 m3/a.