12-9 IRRIGATION, RESERVOIRS, FLOOD PREVENTION, WATER AND SOIL CONSERVATION AND IMPROVEMENT OF SALINE-ALKALINE LAND

Item

1985

1990

1995

1996

1997

Number of Irrigation Areas (year-end)

5281

5363

5562

5608

5579

33 000 Hectares and Over

71

72

74

75

77

20 000-33 000 Hectares

66

76

99

108

115

Effective Irrigated Areas (10 000 hectares)

2077.7

2123.1

2249.9

2206.2

2249.5

33 000 Hectares and Over

599.6

604.7

631.4

615.0

640.8

20 000-33 000 Hectares

167.0

189.6

244.4

266.5

286.2

Number of Reservoirs

83219

83387

84775

84905

84837

Large

340

366

387

394

397

Medium-sized

2401

2499

2593

2618

2634

Small

80478

80522

81795

81893

81806

Capacity of Reservoirs(100 million cu.m)

4301

4660

4797

4571

4583

Large

3076

3397

3493

3260

3267

Medium-sized

661

690

719

724

729

Small

564

573

585

587

587

Total Area Liable to Flooding or Waterlogging (10 000 hectares)

2420.7

2446.7

2442.5

2458.2

2458.2

Flooded or Waterlogged Area Under Control (10 000 hectares)

1858.4

1933.7

2006.5

2027.9

2052.6

Percentage to Total Area Liable to Flooding or Water-logging ()

76.8

79.0

82.2

82.5

83.5

Total Area of Soil Erosion (10 000 hectares)

12920.0

13600.0

16300.0

18266.4

18266.4

Area of Soil Erosion Under Control (10 000 hectares)

4640.0

5300.0

6690.0

6932.1

7224.2

Percentage to Total Area of Soil Erosion ()

35.9

39.0

41.0

38.0

39.5

Total Area of Saline-Alkaline Land (10 000 hectares)

769.3

753.9

765.6

772.5

772.5

Improved Area of Saline-Alkaline Land (10 000 hectares)

456.9

499.5

543.4

551.3

561.2

Percentage to Total Area of Saline-Alkaline Land ()

59.4

66.3

71.0

71.4

72.6

Total Length of Dikes (10 000 km)

17.7

22.0

24.7

24.8

25.1

Area of Land Protected by Dikes (10 000 hectares)

3106.0

3200.0

3060.9

3268.6

3414.6

 

 

 

 

 

 

a)The capacity of the large reservoirs is over 100 million cubic meters, while that of the medium ones is from

 

 

 

 

 

10 million to 100 million cubic meters, and that of the small ones is from 100 000 to 10 million cubic meters.