420
18 Climatic Change and Water Resources
under normal precipitation and 15%–40% in a dry year. In these four river basins,
precipitation decrease contributed to 75% of decrease in surface water resources, of
which 60% in the Yellow River Basin and 80% in the Huai and Hai River Basins.
The following also occurred at the regional level:
• In the source region of the Yangtze River Basin from 1956 to 2004, runoff in the
Zhimenda Hydrological Station saw a “more-less-more-less” process. In terms of
10-year steps, the 1990s was the driest period and the 1980s was the most plentiful
period (Shi et al. 2007).
• In the Yellow River Basin, annual runoff at San-Hua reach decreased at a rate of
537 million m
3 each 10 years, impacted by human activities and climate change
(Li et al. 2007). In the Tao River Basin, runoff decreased 35% during the 1980s and
1990s (Zhang et al. 2003). In the upper reaches of Lanzhou in the Yellow River,
runoff at Lanzhou Hydrological Station from 1990 to 2000 decreased by 18%
compared to the annual average (Qian et al. 2004). In the Weihe River Basin, the
1950s, 1960s, and 1980s measured more runoff, but runoff decreased following
the 1990s (Zheng et al. 2009). In the source region of the Yellow River, runoff
was greater from 1956 to 1969 and 1975 to 1986 and lower from 1969 to 1975
and 1986 to 2004 (Jiang 2008). As a whole, from 1950 to 2017, the runoff of
four hydrological stations along the mainstream of the Yellow River showed a
significant downward trend, and the rate of decline reflected a cumulative effect.
In the 1960s, the Yellow River had the largest amount of runoff in the past century,
but runoff significantly decreased after the 1990s. Runoff for the four hydrological
stations revealed a change point in 1985–1986. The annual runoff in the change
period was significantly lower than the annual runoff in the base period, and the
decline increased from upstream to downstream (Liu et al. 2019).
• In the Nen River, runoff generally increased from 1951 to 2005 (Yang et al. 2008).
• In Hebei Province, water resources decreased decade by decade from 1956 to
2000 (Shao et al. 2008).
• In the out-to-sea river basins of the Tibetan Plateau, runoff did not increase from
1956 to 2000 but rather underwent regional variations: decreases were measured
in the Yellow River and Yangtze River, and increases occurred in the Yalong
River (Cao et al. 2005). In the Karuxung Watershed in the Himalayan Mountains,
runoff in 1994–2003 was 26% greater than that of 1983–1993 due to temperature
increases (Zhang et al. 2006).
• The past 20 years in the Tarim River Basin have been a humid and warm period,
with annual runoff from four source rivers 6.6% higher than the average in the
1990s (Wang et al. 2006). In the Kuitun River Basin, runoff increased at a rate of
20 million m
3 per 10 years from 1963 to 2005 (Jing et al. 2008). In North Xinjiang,
water resources decreased from the middle of the 1950s to the early 1980s, after
which water resources increased (Cao et al. 2008). In Yarkent, Karakorum River,
in the 1950s–1960s and 1980s, monitored runoff was 7.2% and 2.1% lower than
average, respectively. However, in the 1970s, 1990s, and the early twenty-first
century, runoff was 1.2%, 3.4%, and 4.5% more than average, respectively (Sun
et al. 2008). In the Aksu River Basin, runoff underwent a significant increase
18 Climatic Change and Water Resources
under normal precipitation and 15%–40% in a dry year. In these four river basins,
precipitation decrease contributed to 75% of decrease in surface water resources, of
which 60% in the Yellow River Basin and 80% in the Huai and Hai River Basins.
The following also occurred at the regional level:
• In the source region of the Yangtze River Basin from 1956 to 2004, runoff in the
Zhimenda Hydrological Station saw a “more-less-more-less” process. In terms of
10-year steps, the 1990s was the driest period and the 1980s was the most plentiful
period (Shi et al. 2007).
• In the Yellow River Basin, annual runoff at San-Hua reach decreased at a rate of
537 million m
3 each 10 years, impacted by human activities and climate change
(Li et al. 2007). In the Tao River Basin, runoff decreased 35% during the 1980s and
1990s (Zhang et al. 2003). In the upper reaches of Lanzhou in the Yellow River,
runoff at Lanzhou Hydrological Station from 1990 to 2000 decreased by 18%
compared to the annual average (Qian et al. 2004). In the Weihe River Basin, the
1950s, 1960s, and 1980s measured more runoff, but runoff decreased following
the 1990s (Zheng et al. 2009). In the source region of the Yellow River, runoff
was greater from 1956 to 1969 and 1975 to 1986 and lower from 1969 to 1975
and 1986 to 2004 (Jiang 2008). As a whole, from 1950 to 2017, the runoff of
four hydrological stations along the mainstream of the Yellow River showed a
significant downward trend, and the rate of decline reflected a cumulative effect.
In the 1960s, the Yellow River had the largest amount of runoff in the past century,
but runoff significantly decreased after the 1990s. Runoff for the four hydrological
stations revealed a change point in 1985–1986. The annual runoff in the change
period was significantly lower than the annual runoff in the base period, and the
decline increased from upstream to downstream (Liu et al. 2019).
• In the Nen River, runoff generally increased from 1951 to 2005 (Yang et al. 2008).
• In Hebei Province, water resources decreased decade by decade from 1956 to
2000 (Shao et al. 2008).
• In the out-to-sea river basins of the Tibetan Plateau, runoff did not increase from
1956 to 2000 but rather underwent regional variations: decreases were measured
in the Yellow River and Yangtze River, and increases occurred in the Yalong
River (Cao et al. 2005). In the Karuxung Watershed in the Himalayan Mountains,
runoff in 1994–2003 was 26% greater than that of 1983–1993 due to temperature
increases (Zhang et al. 2006).
• The past 20 years in the Tarim River Basin have been a humid and warm period,
with annual runoff from four source rivers 6.6% higher than the average in the
1990s (Wang et al. 2006). In the Kuitun River Basin, runoff increased at a rate of
20 million m
3 per 10 years from 1963 to 2005 (Jing et al. 2008). In North Xinjiang,
water resources decreased from the middle of the 1950s to the early 1980s, after
which water resources increased (Cao et al. 2008). In Yarkent, Karakorum River,
in the 1950s–1960s and 1980s, monitored runoff was 7.2% and 2.1% lower than
average, respectively. However, in the 1970s, 1990s, and the early twenty-first
century, runoff was 1.2%, 3.4%, and 4.5% more than average, respectively (Sun
et al. 2008). In the Aksu River Basin, runoff underwent a significant increase