1. Challenges and Countermeasures in Soil and Water Conservation under Climate Change in the Loess Plateau of China
Dr. Jianen Gao, Huijuan L,Yuanxing Z et al.
Northwest A&F University
Institute of Soil and Water Conservation, CAS&MWR
Aug.22nd.2016
Good afternoon, Professor Zheng, ladies and gentlemen, First, I’d like to thank Professor Zheng and the Conference committee for offering me this opportunity to speak you on a subject of Challenges and Countermeasures in Soil and Water Conservation under Climate Change in the Loess Plateau of China.

2. Outline Backgrounds Rainfall Changes Erosion Changes Challenges
Countermeasures
My report have five part.

3. 1. Backgrounds Area studied in China Beijing Xi’an Shanghai
the Yellow Rive
Area studied in China
Beijing
Loess
Plateau
Xi’an
Shanghai
This is the China map. These are the Yangtz River and The Yelow River. This is the Loess Plateau. The area is 0.62 million km2,The people is about 60 million,and the average Rainfall is 429 mm ( mm)
Area: 0.62 million km2
people: 60 million
Average Rainfall: 429 mm ( mm)

4. Soil erosion intensity map of the Loess Plateau
The Loess Plateau are made of many hills and gullies. The gullies were very deep and hills were rare vegetation. The ecological environment was very bad.
Average erosion intensity:E=3700t/(km2a);Emax= t/(km2a). The soil and water erosion is very serious and controlled difficultly.
The Loess Plateau are made of many hills and gullies. The gullies are very deep and hills are rare vegetation. The ecological environment was very bad. The average erosion intensity was E=3700t/(km2.a);Emax= t/(km2a). The soil and water erosion was very serious and controlled difficultly.

5. The variation of sediment quantity of the Yellow River
The Yellow river is the fifth longest river, but the highest river in sediment concentration in the world.
1919~1959 Annual sediment yield (Ws=)1.6 billion ton，around the earth 30 laps by 1 square volume. Maximum sediment yield Ws max=37 billion ton.
The silt comes from the Loess Plateau mainly.
The erosion and sediment delivery ratio is almost 1
The Yellow river is the fifth longest river, but the highest river in sediment concentration in the world. 1919~1959 Annual sediment yield (Ws=)1.6 billion ton，around the earth 30 laps by 1 square volume. Maximum sediment yield Ws max=37 billion ton.
The silt comes from the Loess Plateau mainly.

6. 1. Rainstorm characteristics
The an important cause of severe erosion is the heavy rainfall. The maximum rain intensity can reach 18.3mm/min.
＞100mm
＞50mm
The an important cause of severe erosion was the heavy rainfall. The maximum rain intensity can reach 18.3mm/min.

7. Annual mean temperature anomaly
2. Temperature Changes(Climate change)
warm period
1960~2001 (42 years)
Temperature increased by
about 1.5 o C
cold period
1987
Annual mean temperature anomaly
The temperature is a mainly characteristic parameter reflecting climate change. This graph is the change of temperature and runoff and precipitation. This graph is the change of annual mean temperature anomaly. From 1960~2001 (42 years),the temperature increased by about 1.5 o C.

8. 2. Precipitation Changes
Comparison of  the precipitation in different ages at the upper and middle yellow river
Compared with 50s and 60s, the annual precipitation in 90s  decreased by 4.2% and 15.2% before Lanzhou section and in
  the middle Yellow River respectively.
Reach
Ages
1956~
1969
1970~
1979
1980~
1989
1990~
2000
1990
Before 
Lanzhou
 section
value（mm）
486
484.4
496.3
465.8
486.9
483.0
anomaly（%）
0.6
0.3
2.8
-3.6
0.8
Lanzhou-Hekouzhen
277.1
265.9
239.4
258.7
264.1
261.7
5.9
1.6
-8.5
-1.1
0.9
Hekouzhen-Longmen
476.7
429.4
414.8
399.3
445.9
433.5
10.0
-0.9
-4.3
-7.9
2.9
Longmen~Sanmenxia
578.8
530.8
551.6
490.4
557.9
540.5
7.1
-1.8
2.1
-9.3
3.2
Sanmenxia-Huayuankou
702.7
641.9
667
608.5
673.6
658.2
6.8
-2.5
1.3
-7.6
2.3
Hekouzhen
560.8
511.5
521.3
475.2
535.7
520.2
7.8
-1.7
0.2
-8.7
3.0
Decreased 3 times
This chart is comparison of  the precipitation in different ages at the upper and middle yellow river. This graph is the Annual mean Precipitation anomaly. compared with 50s and 60s, the annual precipitation in 90s decreased by 4.2% and 15.2% before Lanzhou section and in the middle Yellow River respectively.
Annual mean Precipitation anomaly

9. 2. Precipitation Change (1997-2015)
But since 1997, the precipitation had a obvious rise. This graph was precipitation, runoff and sediment transportation of Ganguyi Station in Yanhe river. From This Graph, There were two precipaions in 2013 and 2014.
The rainfall has an increasing trend since 1997.

10. 2. Precipitation Changes Yanan Precipitation Station
,Precipitation is increasing;
annual: 505.3mm:
2013: 959mm; 2014: 706mm.
Sediment discharge is decreasing;
Runoff is increasing and there was no zero flow for the Yellow River since 1999.
Yanan Precipitation Station
,Precipitation is increasing; annual: 505.3mm: 2013: 959mm; 2014: 706mm.
Sediment discharge is decreasing;Runoff is increasing and there was no zero flow for the Yellow River since 1999.
Tongguan Hydrometric Station

11. 2. Precipitation Changes (2013)
Precipitation Characteristics of 2013 Yan’an
The total precipitation and flood season precipitation of 2013comparison with multi-year average value:1.9,2.1;
The total precipitation and flood season precipitation of 2013comparison with multi-year average value
Monthly rainfall (2013) comparison with annual mean monthly rainfall ( )

12. 2. Precipitation Changes (2013)
The rainfall frequency analysis of Yan’an station in 2013
A significant change in the form of precipitation:
Large amount, Moderate intensity, Long duration

13. 3. Erosion Changes 1、Gravity erosion increasing:
Landslide, Collapidation, Mudflow
Landslide, Collapidation, Mudflow

14. 3. Erosion Changes 2、Reduction of sediment and runoff in Yellow River
The Yellow River natural drying began in 1972, mainly occurred in the lower reaches of the Shandong River. After 1987, stop was almost every year. In , there were drying up of 122 days, 683km.
Reduction of sediment and runoff in Yellow River. The Yellow River natural drying began in 1972, mainly occurred in the lower reaches of the Shandong River. After 1987, stop was almost every year. In 1995, there were drying up of 122 days, 683km.

15. 3. Erosion Changes Erosion transport in Yanhe River
3、Change in the ratio of erosion transport
The change in the ratio of erosion transport from 1 to
Erosion transport in Yanhe River

16. 4.Challenges 1、Gravity Erosion increasing
(1) The amount of precipitation was bigger
(2) Rainfall Intensity becoming smaller
(3) Soil moisture content was increasing
(4) Increased vegetation cover

17. 4.Challenges Who’s faults？
2、River runoff reduction, ecological base flow shortage
(1) The Yellow River breaking
(2) The water resource shortage
(3) The ecological flow shortage
Who’s faults？

18. 4.Challenges 3、The shocking soil erosion in construction projects
(1) Point project: Large slag field
(2) Line project
(3) Surface project

19. 4.Challenges 4、Non-point source pollution (1) Pesticides
(2) Chemical fertilizer
(3) Heavy metal of industrial commodity

20. 5. Countermeasures Rainfall runoff regulation and control technology.
Development of soil and water conservation and high efficiency agriculture.
Research on strengthening soil and water conservation monitoring technology.
Strengthening the slope protection on important projects to prevent the occurrence of gravity erosion.
Explore the law of soil and water loss in construction projects.

21. Thanks for your attention！