Water-level observations of Lake Weishan-Zhaoyang-Nanyang in China during 1814∼1902 AD

Abstract

Fei, J. 2009. Water-level observations of Lake Weishan-Zhaoyang-Nanyang in China during 1814 ∼ 1902 AD.

This article reports the evaluation and preliminary interpretation of the monthly water-level observations of Lake Weishan-Zhaoyang-Nanyang (WZN) in east China during 1814∼1902 AD. Observations were conducted by the government. According to the extant historical literature, the gaps in observations for this time period are 13.2%, 24.9%, and 24.5%, respectively, for the three parts of the lake: Weishan, Zhaoyang, and Nanyang. After a preliminary interpretation, we suggest that a correspondence exists between the high water-level years of Lake WZN and the flood years of the Yellow River during 1814∼1902 AD.

Key words:

• flood
• lake
• observation
• Qing dynasty
• water-level

Fluctuations of lake water levels during historical times have been widely investigated using anecdotal historical accounts (Nicholson 1999, Nicholson and Yin 2001), lake sediments (Haberzettl et al. 2005), and geomorphological evidence (Nielson 1998).

In China, modern hydrological observations of lakes commenced in the mid-20th century. Here we report the discovery, evaluation, and preliminary interpretation of the monthly water-level observations of Lake Weishan-Zhaoyang-Nanyang (WZN) in east China during 1814∼1902 AD (Fig. 1).

Figure 1 Location of Lake Weishan-Zhangyang-Nanyang (Revised from Chinese Academy of Social Sciences 1987).

Study site

Lake WZN (34.5–35.1°N; 116.7–117.3°E) is a long, narrow, shallow freshwater historical lake in east China (Fig. 1). Its wide south part is usually called Lake Weishan; the narrow north part is usually called Lake Zhaoyang; and its north end is usually called Lake Nanyang. Lake WZN is a united lake, though its different parts have different names (Li and Pan 1813, AWCHP 1988).

A few small rivers originate from nearby mountains and flow into Lake WZN (Fig. 1). Water in Lake WZN flows southward into the Grand Canal and finally flows into the East China Sea (AWCHP 1988). The climate in this area is a warm, temperate, semi-humid monsoon type. The annual mean temperature and annual total precipitation are about 14°C and 700 mm, respectively (Liu 1998, Wang and Dou 1998).

The long-term evolution of Lake WZN has been extensively investigated through historical accounts (Zou 1980, Cao 1989a, Cao 1989b, Han 2000) and lake sediments (Shen et al. 2000, Zhang et al. 2002). A united Lake WZN was formed during the middle 18th century (Zou 1980, Cao 1989a, Cao 1989b, Han 2000), whereas several isolated small lakes in this area had been possibly formed as early as two millennia ago (Shen et al. 2000, Zhang et al. 2002).

During the mid-18th century and early 20th century, Lake WZN was a major reservoir (called shui-gui in classical Chinese, which means shui-ku in modern Chinese and ‘reservoir’ in English) on the Grand Canal, which regulated the water-level of the Canal (Li and Pan 1813, Zhao and Ke 1927, AWCHP 1988).

In the 1870s, Lake WZN merged with Lake Dushan (Fig. 1; Wu 1942, AWCHP 1988, Cen 2004). During the late 19th century and early 20th century, the lake expanded continually northward. A dam was constructed in the middle of Lake WZN in 1960, cutting it into two parts, the upper (north) and lower (south; Wang and Dou 1998).

Results

The water-level observations of Lake WZN are of vital importance to regulating the water-level of Grand Canal, and Grand Canal transportation was of vital importance to the Qing Dynasty (1644∼ 1912 AD). Monthly observations and reports of Lake WZN water-levels commenced in 1814 at the decree of Emperor Jiaqing (reign in 1796∼ 1820 AD; Li and Pan 1813, AWCHP 1988, Man 2000). The observations were conducted by the government and reported to the emperor monthly (Li and Pan 1813, AWCHP 1988).

The original literature of the observations is scattered through the millions of imperial archives of the Qing dynasty, which are archived in the No. 1 Historical Archives of China (Zhongguo Diyi Lishi Danganguan). The Academy of Water Conservancy and Hydroelectric Power (AWCHP) sorted out and compiled the extant literature on floods in the Huaihe River Basin (AWCHP 1988), which we used for the research of the monthly water level observations of Lake WZN during 1814∼1902 AD.

The lake water level observations were conducted regularly during the last days of each Chinese calendar month. Note that the water levels were not the levels above sea level, but the depths of the waters at the observing stations (AWCHP 1988). The observing station of Lake Weishan is at a sluice called Hukou Shuangzha, whereas those of the Zhaoyang and Nanyang lakes are not definitely known (AWCHP 1988; Fig. 1).

A unique Chinese unit of length, yingzao chi (henceforward yc; 1 yc = 0.32 m) is adopted in the observations, which is the standard unit of length adopted by the government of the Qing Dynasty (AWCHP 1988, Qiu et al. 2001).

The Chinese calendar is a unique lunar calendar, of which a New Year's Day is generally in January or February. Most years contain 12 lunar months, each 29 or 30 days. Approximatly every three years, an intercalary month is inserted to keep the calendar in step with the seasons (Willis and Stephevenson 2000). Conversions of Chinese calendar dates to AD dates are made using software designed by the Academia Sinica, which is available on line (http://www.sinica.edu.tw/~tdbproj/sinocal/luso.html).

The observations should be continuous, but a few gaps exist in the extant observation literature. Over the period 1814∼1902 AD, gaps amount to 13.2%, 24.9% and 24.5% for Lake Weishan, Zhaoyang, and Nanyang, respectively (Table 1; Fig. 2).

Figure 2 The monthly water-level observations of Lake Weishan-Zhaoyang-Nanyang during 1814–1902 AD.

Table 1 The water-level observations of Lake Weishan-Zhaoyang-Nanyang in a Chinese calendar year (the 26th year of the Guangxu Reign Period; i.e., 31 Jan 1900 ∼ 18 Feb 1901 AD. The conversions to AD dates and SI units are added).

Observing dates		Lake Water-levels in yingzao chi ( yc ) and meters (m)
Chinese calendar	AD	Lake Weishan		Lake Zhaoyang		Lake Nanyang
29th, 1st ^1	28 Feb 1900	8.6 yc	2.752 m	4.5 yc	1.44 m	5.2 yc	1.664 m
30th, 2nd	30 Mar 1900	8.6	2.752	4.5	1.44	5.2	1.664
29th, 3rd	28 Apr 1900	8.6	2.752	4.5	1.44	5.2	1.664
29th, 4th	27 May 1900	8.6	2.752	4.3	1.376	5	1.6
30th, 5th	26 Jun 1900	8.9	2.848	4.3	1.376	5.2	1.664
29th, 6th	25 Jul 1900	8.4	2.688	Gap	Gap	Gap	Gap
30th,7th	24 Aug 1900	9	2.88	4.8	1.536	5.7	1.824
30th, 8th	23 Sept 1900	9	2.88	5.1	1.632	6	1.92
29th, Intercalary 8th	22 Oct 1900	8.1	2.592	5.1	1.632	6	1.92
30th, 9th	21 Nov 1900	7.7	2.464	4.7	1.504	5.6	1.792
30th, 10th	21 Dec 1900	7.7	2.464	4.5	1.44	5.4	1.728
29th, 11th	19 Jan 1901	8	2.56	4.5	1.44	5.4	1.728
30th, 12th	18 Feb 1901	8	2.56	4.5	1.44	5.4	1.728

Discussion

Our preliminary interpretation of the annual water-level fluctuations of Lake WZN is that the 10 highest/lowest water-level years of in the three parts of Lake WZN (i.e. Weishan, Zhaoyang and Nanyang) coincide with the floods of the Yellow River (Table 2). The Yellow River directly flooded Lake WZN in 1851, 1852, 1853, 1871, and 1873 AD (Wu 1942, AWCHP 1988, Cen 2004). The direct floods of the Yellow River in 1851∼ 1853 possibly affected Lake WZN significantly. The Yellow River changed its course in 1855, and Lake WZN was also significantly affected and the water-level was very high. These floods were followed by a high water level interval of about five years (1851∼ 1855; Table 2; Fig. 2).

Table 2 A comparison of the 10 highest/lowest water-level years Lake WZN and the flood years of the Yellow River during 1814-1902 AD ¹ , ² .

	10 highest water-level years	10 lowest water-level years
Weishan	1832, 1851, 1852, 1853, 1855, 1866, 1874, 1875, 1883, 1898	1826, 1839, 1856, 1878, 1885, 1886, 1887, 1888, 1900, 1901
Zhaoyang	1832,1851, 1852, 1853, 1855, 1866, 1871, 1874, 1875, 1883	1825, 1826, 1839, 1867, 1869, 1876, 1878, 1885, 1888, 1886
Nanyang	1851, 1852, 1853, 1855, 1866, 1871, 1874, 1875, 1883, 1898	1825, 1826, 1838, 1839, 1843, 1869, 1876, 1878, 1885, 1888
Flood years of	1819, 1820, 1824, 1832, 1841, 1842, 1843, 1851, 1852, 1853, 1855, 1863, 1866, 1868, 1871, 1873, 1878, 1880,
the Yellow River	1882, 1883, 1884, 1885, 1886, 1887, 1889, 1892, 1895, 1896, 1897, 1898, 1900, 1901, 1902

The floods of the Yellow River in 1871 and 1873 affected Lake WZN even more significantly. The northern banks of Lake WZN were destroyed, and the lake expanded northward and merged with Lake Dushan (Fig. 1; Wu 1942, AWCHP 1988, Cen 2004). There are at least three high water-level years (1871, 1874, and 1875, with a gap of one year in 1873) in Lake WZN following the floods of the Yellow River in 1871 and 1873.

The Yellow River had 33 flood years during 1814∼1902 AD (Cen 2004). In most cases, Lake WZN was not directly flooded by the Yellow River; however, most of the high water-level years of Lake WZN (1832, 1851, 1852, 1853, 1855, 1866, 1871, 1883, and 1898) correspond with flood years of the Yellow River, indicating a potential relation between the two water bodies. Two high water-level years of Lake WZN that do not correspond with the flood years of the Yellow River (1874 and 1875), should be related to the aftereffects of the direct floods of the Yellow River.

Some low water-level years of Lake WZN coincide with flood years of the Yellow River during 1878∼1902 AD (Table 2). It seems that the relation between Lake WZN and the Yellow River has changed since the 1870s when the lake merged with Lake Dushan and expanded northward. However, the high water-level years (1883 and 1898), also correspond with the flood years of the Yellow River.

The annual water-level fluctuations of Lake WZN should be related to the Yellow River floods because a correspondence exists between the high water-level years of Lake WZN and the flood years of the Yellow River. When Lake WZN is directly flooded by the Yellow River, the effects of the Yellow River are more significant. However, the interpretation of lake water-level fluctuation is a complex problem. The floods of the Yellow River should not be the sole factor that affects the water-level fluctuations of Lake WZN; and other potential factors (e.g., precipitation) should not be excluded.

Modern meteorological observations in this area commenced in the middle 20th century. Historical accounts, which are difficult to analyze quantitatively, are traditionally utilized to investigate the environmental history (China Meteorological Administration 1981, Zhang 2004). The water-level observations of Lake WZN would be helpful to better understand the environmental history in the area because they are high resolution quantitative observational data.

Conclusion

The monthly water-level observations of Lake Weishan-Zhaoyang-Nanyang in east China during 1814∼1902 AD were evaluated and preliminarily analyzed. According to the extant historical literature, gaps of the observations amount to 13.2%, 24.9%, and 24.5% for the three parts of the lake: Weishan, Zhaoyang, and Nanyang.

As a whole, the water-level fluctuations of Lake WZN is related to the floods of the Yellow River over 1814∼1902 AD. The high water-level years of Lake WZN correspond with the flood years of the Yellow River. The lake was directly flooded by the Yellow River in the 1850s and 1870s, and the effects of the floods should be particularly significant.

Acknowledgments

We wish to thank Professors Hua-Kai Hu, Jie Zhou and Qian-Li Sun for the kind suggestions. This research was supported by the 2009 Anhui Provincial Foundation for the Outstanding Young Talents in Colleges and the 2006 Presidential Award of the Chinese Academy of Sciences.

Notes

¹Denotes the 29th day (i.e., the last day) of the first month.

¹Bold: high water-level year of Lake WZN that corresponds with a flood year of the Yellow River. Italic: low water-level year of Lake WZN that corresponds with a flood year of the Yellow River.

²Data of the flood years of the Yellow River are from Cen (2004).