Retreating the Lake: Evolution of Dongqian Lake Shoreline in Ningbo since Song Dynasty

Lead: There are many lakes in Ningshaoping on the south bank of Hangzhou Bay, such as Xianghu Lake, Jianhu Lake, Guangde Lake and Dongqian Lake. Due to human activities and the life of the lagoon itself, some lakes gradually disappeared in the long river of history. However, due to the need of irrigation, some lakes have been continuously dredged and their life span has been extended. Dongqian Lake in Ningbo is 8.5 kilometers long from north to south, 6.5 kilometers wide from east to west, 45 kilometers around the lake, 19.89 square kilometers. It is the largest freshwater lake in Zhejiang Province. In history, there have been many disputes about "abandoned lake" in Dongqian Lake, and the surrounding land has been reclaimed continuously, and its coastline has been pushed to the center of the lake. Ningbo dongqian lake 1. Changes of Lake Body in Dongqian Lake; Dongqian Lake is surrounded by mountains on three sides. Due to the limitation of topography, the lakeshore is relatively stable. There is a gap in the mountains in the northwest, and a weir dam is built in the mountains, which is the main inlet and outlet canal of Dongqian Lake. Song Baoqing's "Four Wisdom" records that "Dongqian Lake, thirty-five miles east of the county, is called Wan Jinhu Lake, which is important for its benefit. In the Tang Dynasty, it was called West Lake, and when it was renamed as the county, it was also in the west of the county. In the third year of Tianbao, the county magistrate Liu Nanjin opened to the outside world, and the dynasty repeatedly ruled. Back to eighty miles, it was influenced by the flow of seventy-two streams and seven weirs on four banks, which was called Qian Weir. Many people regard Seven Eyes as the coastline of Dongqian Lake in Tang Dynasty. If the location of the Seven Weirs is determined by the map of Dongqian Lake in Tongzhi's Yinxian Tongzhi, the shore of Dongqian Lake has not changed much since the Tang Dynasty. In the aerial photography in the 1960s, the red line indicated the coastline of Dongqian Lake in the Song Dynasty, but the eastern part of Zhejiang Province was long and narrow and densely populated. With the increase of population and the acceleration of development, the situation of reclamation around lakes is becoming more and more serious. Jianhu Lake, the giant lake in Ningshaoping, has disappeared, as has Guangde Lake, which is also located in the west of Yinxian and Dongqian Lake. Guangde Lake was once surrounded by hundreds of miles, surrounded by elms and willows in dike ponds and Doumen. The coastline of Guangde Lake is longer than that of Dongqian Lake, and it is doomed to disappear in the end. Dongqian Lake also faced reclamation crisis in history, but it finally survived. 2. Changes of the coastline in the west of Dongqian Lake According to the aerial photos of Dongqian Lake in the 1960s, the estuary river in the west of Dongqian Lake is in a state of "two sharp ends and thick middle". This olive-shaped river may be the remains of a lake after reclamation. According to the calculation of "Tiantu Zhejiang", the width of the two main estuary rivers is only about 50 meters near the lakeside, and the downstream reaches 100-200 meters, and then gradually narrows. The distribution of settlements around the old dam of Dongqian Lake also reflects that this area may have been a lake before the Song Dynasty. The gazetteer of Yinzhou District, Ningbo published in 2006 not only included the place names, but also included the time when the village was built by using genealogy, field investigation and other materials. The information provided by the list of base areas can draw a starting line for rural construction in the Song Dynasty on the west bank of Dongqian Lake. Wangjiaao Village: At the end of the Song Dynasty, Wang Zhufang moved in and settled from Yushantou, Yinjiang (now Dongqiao). Dijiang Village: The villager's democratic surname is Zhang, who moved to Zhang Cun to settle down in the Southern Song Dynasty. Shuangqiao village: the surname of the village democracy is Xu. During the Song Dynasty, he moved to garden village, Maoshan. Dai Jia 'an: The surname of the village democracy is Dai, who moved from Daijia, Dayantou, Dongqian Lake in the Northern Song Dynasty. Huang 'ai Village: During the Song Dynasty, a man named Huang moved from here to settle down. Because it is located at the intersection of Mozhi and Xia Ying, it is called Huangai. Yamashita River: What is the name of democracy in the village? In the Song Dynasty, he moved from Wangchun Xixiang to settle down. There is Ping 'e Mountain next to the village, and there is a river under the mountain, so it is called Yamashita River, also called Yamashita River. Villages near Dongqian Lake can be connected into a complete line, from Fengtou Mountain in the south to Baishi Mountain in the north. The villages near Dongqian Lake to the east of this line were all built after the Song Dynasty, and there are many villages built in the Song Dynasty or even earlier to the west of this line. To the east of this line, there is a village called Dunao, which is located at the foot of Fengtou Mountain, not on the plain in the east. The village is at the foot of the mountain, probably because the east is part of the original lake, and the lake goes directly to the side of the mountain. Moreover, there is a river parallel to the mountain in the village. Topographically, this river can't be made up of water from the surrounding mountains, but it looks like the remains of a lake after reclamation. There is an island outside Taogong Village near Dongqian Lake, which is a breakwater built to prevent the shoreline from collapsing due to the impact of lake water. A small river just formed between the island and Miyamura. The reason for the formation of the river on the edge of Dunao Village may be similar to this. According to place names, Dun 'ao Village was the residence of Xu in Huxishu Lane, Ningbo in Ming Dynasty. This shows that at least before the Ming Dynasty, the eastern part of Dunao Village was a lake bay. Taogong Mountain on the west bank of Dongqian Lake is a settlement around Dongqian Lake, and it was an island in the center of the lake in the Ming Dynasty. In the Records of Yinxian County compiled during the reign of Kangxi in Qing Dynasty, there is a poem "Taogong Mountain is in Dongqian Lake, forty-five miles away from the sixteenth capital", and it also records a poem by the poet Ba "Take this opportunity to sit on the fish beach all day long. "A very romantic name, let bygones be bygones. The spring rain is barren and covered with moss, and the fishing boat returns at dusk. I want to try to climb to the top, and the water flies relentlessly. " Fishing in Taogong, Los Angeles is a scene of Taogong Mountain, and it is obvious in the poem that you need to go to Taogong Island by boat. This reflects that Taogong Mountain is an island in Dongqian Lake. However, in the field investigation, we found that Taogong Mountain is connected with the surrounding land, and it is only a peninsula, not an island. This can also prove that the plain of Taogong Shanxi was still the lake area of Dongqian Lake in the Ming Dynasty. In this area, the former high ball pond and flat pond may be the remains of the lake. According to the above inference, the coastline west of Dongqian Lake in Song Dynasty should be near the red line, and then gradually close to the lake area with reclamation. Guan Ying Village was built in the Yuan Dynasty, and the coastline of the Yuan Dynasty was roughly on the east side of Guan Ying Village. Since the Ming Dynasty, the coastline has been maintained at the present dam line. 3. The coastline in the north of Dongqian Lake has changed. To the north of Dongqian Lake is Humei Lake, which has been silted up. On the map of Dongqian Lake in Tongzhi period of Qing Dynasty, Humei Lake still existed. There are three gaps in the mountains around Hu Mei, one near Yantou Village, one near Hu Mei Village and the other near Lishutang Village. The gap between the north and the west is different. The gap is very narrow and the mountains on both sides are very close. Dongqian Lake itself has a tendency to swamp in history, and aquatic plants are intertwined, which is conducive to sediment deposition. These three gaps are relatively narrow, which should be silted up in the early stage, leaving only three outlet rivers. At the time when the settlement around Dongqian Lake was formed, Qiantou Yantou built a village in the Song Dynasty. Hu Mei Village was built in Ming Dynasty, but Fangshui Village in the north was built in Song Dynasty. In Song Dynasty, the port line of Humei Lake should be between Hu Mei Village and Fangshui Village. However, Lishutang Village lacks data and cannot be estimated. According to Baoqing's Siming Zhi, the coastline of Hu Mei in the Ming Dynasty was in the areas of Qianyantou Village, Hu Mei Village and Lishutang Village. It was still here in the Qing Dynasty. After the founding of People's Republic of China (PRC), Humei Lake was reclaimed and state-owned farms were established. After aerial photography in the 1960s, Humei Lake has completely disappeared. The picture comes from the network, and the infringement is deleted. References: 1. Zhuo Luo et al., Song's "Four" 2. Wen Xing Dao, etc., Records of Hidden Sages by Emperor Kangxi of Qing Dynasty 3. Dong Pei waiting, Qing Tongzhi "Yin Xian Zhi" 4. Ningbo Yinzhou Geographical Names Compilation Committee, Ningbo Yinzhou Geographical Names 5. Zong Wangfa's "Water Conservancy" Welcome to the headline number/WeChat official account: Jiangnan Weng