l09e

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. |  |  |  |  |