Yanshan Mountains run east-west in the northern part of the basin. There are Du Jun and Taihang Mountain in the west, and the three mountains form an arc barrier, surrounding the Haihe Plain. Due to structural fracture and subsidence. Several intermountain basins have been formed in the mountainous areas. Haihe plain can be divided into piedmont alluvial fan plain, middle alluvial plain and coastal plain according to its genesis. The tributary of Haihe River flows from the mountain to the plain. Due to the steep slope, the water flow is slow and the sediment sinks. The more siltation there is in the river bed, the higher it is. We must rely on flood levees to divert water. Over time, the riverbed is higher than the ground on both sides of the river, forming a "semi-overground river" or "overground river". The flood discharge capacity of rivers is decreasing, and a depression is formed between the two rivers. Every time there is a flood, it is easy to burst and flood, and the drainage often accumulates in the depression, so it has become an area prone to floods and alkali waterlogging in Hebei Province.
Haihe plain, also known as Hebei plain, has a southwest slope in the northeast and a northwest slope in the southeast. The tributaries of Haihe River flow from the mountainous areas in the north and west to Hebei Plain, converge near Tianjin, the lowest terrain, and then flow into the sea through the main stream of Haihe River in the east. The geological structure in the basin can be divided into three parts: north, west and southeast.
Most of the northern part of the basin is located in the east-west complex structural belt of Yinshan and Yanshan. Yinshan Mountain in the western section is mostly composed of pre-Sinian granite gneiss and diorite gneiss, and there are Mesozoic clastic rocks and a large number of volcanic rocks in some areas. The eastern Yanshan Mountains are widely distributed with Sinian quartzite and siliceous limestone, lower Paleozoic shallow sea sedimentary shale and limestone, and upper Paleozoic coal-bearing structures. In Yinshan and Yanshan areas, Mesozoic tectonic movement was strong, faults developed and the ground uplifted for a long time. The rocks were weathered and denuded, forming gentle hills and mountains.
Taihang Mountain in the west of the basin is a part of the third uplift zone of Xinhua Xia, and the northeast is composed of a series of gentle composite folds, and the east is connected with Hebei Plain by a fault zone. The rocks in Xiaowutai Mountain range in the north are gneiss, schist and granite, while the rocks in the south are composed of quartzite, sandstone shale and limestone deposited in Sinian and Lower Paleozoic. It is the birthplace of Yongding River, Juma River, Hutuo River and Zhanghe River. The upper reaches of Sanggan River, Yehe Jingxing Basin and Zhanghe Shexian County are developed with karst and rich springs.
Hebei plain in the southeast of the basin belongs to the second subsidence zone of Neocathaysia in geological structure. The basement is alternately formed by a series of north-northeast and north-east uplifts and depressions, and there are deep Cenozoic loose deposits on it, which are thousands of meters thick. The sediments here are mostly river and lake sediments except alluvial fans at the foothills and thin marine sediments along the coast. There are also Quaternary basalt eruption interlayers in some areas of the sedimentary layer. Haihe river basin belongs to warm temperate semi-dry and early semi-humid monsoon climate. Although it is close to the Bohai Sea, the Bohai Sea is an inland sea, which has little influence on the temperature, so the continental climate is remarkable and the temperature changes rapidly.
The average annual temperature in Haihe River Basin is 4- 14℃, and the 10℃ isotherm is roughly from Shanhaiguan in the northeast of Hebei Province, bypassing the north side of Beijing, then turning southwest and passing through the basin. The average temperature of 65438+ 10 is -2~-9℃, and the average temperature of July is above 20℃ except for the mountains. Most of them are 23~27℃.
The annual precipitation in Haihe River basin is the least in the eastern coastal basin of China, with an average annual precipitation of 400-700 mm. The precipitation is unevenly distributed in different regions, with the most precipitation at the southern foot of Yanshan Mountain and the eastern foot of Taihang Mountain, with an annual precipitation of 700-800 mm, forming an arc rain belt. There are several rainy centers in the rain belt, such as cicada house, roe, manshan, tielingkou and pocang. The annual precipitation is about 700 mm The north of Yanshan Mountains and the west of Taihang Mountains are far away from the sea, and they are on leeward slopes. The annual precipitation is only 400~600 mm. For example, Yuxian and Zhangjiakou are all around 400 mm, and the annual precipitation in Hebei Plain is 500~600 mm, while Jixian, Hengshui, Shenze and Shulu are only 400~500 mm, which is the place with the least precipitation in Haihe Plain.
The precipitation in Haihe River Basin is unevenly distributed during the year, with more precipitation in May-65438+1October, accounting for more than 80% of the annual precipitation. Among them, July and August are the most, which can account for 50~60% of the annual precipitation. The concentration of precipitation is also the most prominent in the eastern coastal provinces.
Summer precipitation mostly falls in the form of heavy rain, and heavy rain (daily precipitation 100 mm or more) and extremely heavy rain (daily precipitation over 200 mm) mostly occur in the eastern foothills of Taihang Mountain and the southern foothills of Yanshan Mountain. For example,1rainstorm occurred from October 9 to June 5 1939, with precipitation of 3 18.4 mm in Changping in the north and 35 1.7 mm in Shijiazhuang in the south. During the period of 1963, a torrential rain occurred in Haihe River Basin, with its center located in Zhang Yao, Neiqiu County. The seven-day precipitation is 205 1mm, which is equivalent to three times the normal annual precipitation in this area, and the maximum precipitation in a single day is 865 mm. Caused a huge disaster.
Another feature of the precipitation in Haihe River Basin is its large annual variability, with an average annual variability of more than 20%. The maximum annual variability can reach 70~80%, and the ratio of maximum annual precipitation to minimum annual precipitation is generally 2~3 times, and individual stations can reach 5~6 times. For example, in the summer of 1963, the precipitation at the eastern foot of Taihang Mountain is generally above 900 mm, while in the summer of 120~ 150 mm, the difference is more than 6 times, and some stations even reach 10 times.
The spring precipitation in Haihe River basin only accounts for about 10% of the whole year, and the spring precipitation changes greatly. At this time, it is in the water demand period of crops. In some years, it doesn't rain from April to May, and spring drought often occurs.
The phenomena of concentrated precipitation, great interannual variation, drought in spring and waterlogging in autumn in Haihe River basin directly affect the hydrological characteristics of Haihe River. The vegetation coverage area of Haihe River basin is not large, but there are differences in different parts of the basin. In the upper reaches of Yongding River, Hutuo River and Zhang Zhuo River, the mountains are steep and the yellow soil is widely distributed in the basin. In addition to scattered forests, the alpine region has small vegetation coverage, concentrated rainstorm and serious soil erosion, which has become several major sediment sources in Haihe River Basin.
The upper reaches of Daqing River and Fuyang River are the windward slopes of Taihang Mountain, with steep mountains and abundant precipitation. It turns out that the forest is dense. High vegetation coverage. Although the loess is less distributed here, before the founding of the People's Republic of China, the forest was almost destroyed due to deforestation, resulting in more than 60% of the area becoming bare mountains and hills, which caused serious soil erosion. After the establishment of People's Republic of China (PRC), a series of measures were taken to protect vegetation, such as closing hillsides to facilitate afforestation, and the remaining secondary forests on the mountains were restored and developed. At the same time, the newly planted area is also increasing year by year, and the phenomenon of soil erosion is gradually reduced.
The middle and upper reaches of Chaobai and Jiyun Canal are located on the windward slope of Yanshan Mountains, with more precipitation and less loess distribution. There are patches of forests in mountainous areas above 1000 meters above sea level, and secondary forests and shrub slopes below 1000 meters above sea level, with good vegetation growth. Among them, the vegetation coverage in the north of the Great Wall is greater than that in the south of the Great Wall, and the lower reaches of Yanshan hilly area are covered with grass, with poor vegetation. At present, the vegetation coverage of Haihe River Basin is small, soil erosion is widespread and serious, and Haihe River has become a sandy river. Haihe River Basin is one of the birthplaces of Chinese civilization, with rich prehistoric culture, which became the political and cultural center of the whole country during the Yuan, Ming and Qing Dynasties. As early as 2 million years ago, there were human activities in the Haihe River Basin. Xiaochangliang site and Ma Quan ditch site were found in Sanggan River basin, a tributary of Yongding River, 654.38 0.36 thousand years ago, belonging to the early Paleolithic period. 600,000-700,000 years ago, in the Gulong Cave in Zhoukoudian, southwest of Beijing, primitive humans lived, which we called "Beijingers". During the long Paleolithic period, there were human activities in the Haihe River basin from the middle and upper reaches of Yongding River to the upper reaches of Zhangwei River. From about 10000 BC to 3000 BC, the Neolithic remains in Haihe River Basin mainly include Emeikou Stone Field in Shanxi, Cishan Site in Hebei, Hougang Site in Anyang, Henan, and Sanguan Site in Yuxian, Shanxi, which are distributed on Sanggan River, Fuyang River, Ziya River and Weihe River respectively. The Cishan site advanced the record of millet planting in the Yellow River valley of China to more than 7,000 years ago, filled the blank of pre-Yangshao culture, and revised the understanding of the age of millet planting in the world agricultural history. Archaeologically named "magnetic mountain culture", 1988 was designated as a national key cultural relics protection unit by the State Council.
Zhuolu in Sanggan River valley is the settlement of Huangdi tribe, where livestock are domesticated and crops are planted, and animal husbandry and agriculture are gradually invented. According to legend, the Yellow Emperor ordered He Zhanri, Chang Zhanyue and land astrology, so there was primitive astronomy; So that Cangjie made great efforts to create characters, so he had the original characters and calendars; Linglun made musical instruments and began to have the initial creation of music. Not only that, they also invented sericulture, silk reeling and silk weaving. At the same time, the construction of "Palace" began in the era of the Yellow Emperor, which was the first in the primitive architectural art in China. In addition, in ancient literature, there are legends that Huangdi clan, Li clan, Miao nationality and Yi nationality fought in Zhuolu area and gradually merged to form the Chinese nation. According to records, Dayu's water control activities were mainly in the middle and lower reaches of the Yellow River Basin, which is now the Hebei Plain.
According to legend, the ancestor of Shang Dynasty once lived in the lower reaches of Zhanghe River and then grazed on Yishui, a tributary of Daqing River. The Western Zhou Dynasty was established. In the early years of the Western Zhou Dynasty, Duke Zhou put down the rebellion in the East, implemented the system of enfeoffment and patriarchal clan system, and established garrisons throughout the country. Among the important feudal countries, there are two in Haihe River basin: Wei and Duchaoge (now north of Jixian County, Henan Province), with Qishui area as its ruling center; Yan, Du Ji (present-day Beijing), with the lower reaches of Yongding River as its ruling center, reached the source of Qinglong River, a tributary of Luanhe River. During the Spring and Autumn Period and the Warring States Period, due to the use and popularization of iron production tools, the improvement of farming technology and the construction of water conservancy projects, agriculture in Haihe River Basin has made great progress. With the development of productivity and social economy, some economic metropolises have been formed. Handan and Zhongshan in Zhao, Ji in Yan and Puyang in Wei were all famous cities at that time. In particular, Handan's "Zhuo Yan in the north and Zheng and Wei in the south" communicated the connection between the north and the south of the Central Plains and promoted the social, economic, ideological and cultural development inside and outside the region. During this period, there was a fierce debate among various schools representing the interests of all classes and strata. They competed to run schools and write books, which formed the so-called "a hundred schools of thought contend" situation in the history of ancient academic thought, left a wealth of cultural classics for later generations, and emerged many famous historical figures. For example, thinkers Shen Dao, Gong Sunlong and Xunzi, politicians Yan Zhaowang and Zhao Wuling Wang, military strategists Gui Guzi and Sun Wu, famous ministers Zhao Sheng and Lin Xiangru, famous soldiers Le Yi, Lian Po and Li Mu, and water conservancy expert Ximen Bao.
During the Three Kingdoms, the Jin Dynasty and the Southern and Northern Dynasties, the society in Haihe River Basin was in turmoil, with constant wars, and the economic, social, scientific and cultural development was slow. In the Western Jin Dynasty, many literati lived in seclusion in the mountains, drank wine, talked about metaphysics, studied classics and wrote poems, among which the Seven Sages of Bamboo Forest were the most famous. According to textual research, their activity place is in the upper reaches of Weihe River (now Aibo, Henan Province). After the demise of the Western Jin Dynasty, northern China entered the Sixteen Kingdoms period. Among them, Han, Hou Zhao, Hou Yan, Southern Yan and other countries are all in the Haihe River Basin. Metaphysics flourished in the Northern Wei Dynasty, Buddhism spread further and made great achievements in literature, history, art, geography, science and technology. Many outstanding figures have emerged in Haihe River Basin, such as geographer Li Daoyuan, mathematician Zu Chongzhi, painter Yang Zihua, calligrapher Lu Qian and Cui Yue. During this period, sculptures and folk songs shone brilliantly and prospered for a while. With the spread of Buddhism, Daxing Grottoes in Haihe River Basin, among which Yungang Grottoes are world-famous.
During the Sui and Tang Dynasties, due to national unity, the society was relatively stable, the population of Haihe River Basin increased, water conservancy was built, agriculture was developed, handicrafts (mainly silk weaving, porcelain making, paper making and printing) flourished, land and water transportation was convenient, commercial exchanges were frequent, and economy, society, science and technology and culture showed prosperity. The Sui Dynasty built the world-famous North-South Grand Canal, and its excavation played an important role in consolidating the central government's rule over the southeast region and strengthening economic and cultural exchanges between the North and the South. During the Northern and Southern Dynasties, Confucian classics were different from the North and the South. "The Scholar's Biography of Sui Shu" said: "Southerners can simplify the complex and win their glory; The north is deep and the branches and leaves are poor. " The Sui Dynasty inherited the academic atmosphere of the Northern Dynasty and carried it forward. In terms of bridge construction, Zhao Zhouqiao (located in Jiaohe, Hebei Province) designed and built by Li Chun, an outstanding craftsman in Sui Dynasty, is the oldest stone arch bridge in the world.
After the establishment of the Tang Dynasty, the culture of Haihe River Basin was splendid, and it made brilliant achievements in religious thought, literature and art, history, science and technology, and produced such outstanding figures as Li Baiyao, Li Jifu, Lu, Gao Shi, Liu Changqing, Jia Dao, Kong, monk and his party.
During the Northern Song Dynasty, the Song and Liao Dynasties divided the Haihe River basin into two parts with the boundary river as the boundary. After the disaster of Jingkang, Haihe River basin was under the rule of Jin Dynasty. During the Song and Liao Dynasties, the porcelain industry and temple tower construction industry in Haihe River basin were very developed. In terms of porcelain making, Ding Kiln in Quyang, Hebei Province, attracted porcelain kilns all over the world to follow suit with its fine production, amazing decorative skills and elegant wind crown, forming a Ding Kiln porcelain system. Ding kiln porcelain system, represented by white porcelain, stood out among the kilns in the Song Dynasty. "The snow in the mountains is full, and the beauty comes under the moonlight tree" can slightly express one of its elegant charms. Accompanied by it, there is also the Cizhou kiln system. Its kiln sites are distributed in today's Henan, Hebei and Shanxi provinces. Important kiln sites are Guantai Kiln in Cixian County, Hebei Province, Hebi Kiln in Henan Province and Dangyangyu Kiln in Xiuwu. In the temple tower construction industry, it is famous for the wooden tower in Yingxian County, Shanxi Province. In addition, there are the tallest existing brick-wood pagodas in China, which were built in the Song Dynasty-Kaiyuan Temple Pagoda in Dingzhou, Hebei, Taki Palace in Jingzhi Temple and Taki Palace in Fang Jing, Zhengding longxing temple in Hebei, Liaojin Temple Pavilion in Huayan Temple in Datong, Shanxi, and Dule Temple in Jixian, Tianjin. During the Jin Dynasty, famous writers such as Yuan Haowen and Zhao Bingwen appeared in the basin.
Since the Yuan Dynasty, Beijing in Haihe River Basin has become the capital of all dynasties, and Haihe River Basin has become the political and cultural center of China, which has promoted the economic and cultural development of China.