13-10  Irrigation, Reservoirs, Flood Prevention, Water and Soil Conservation and Improvement of Saline-Alkaline Land
Item	1990	1995	2000	2003	2004	2005
Number of Irrigation Areas at the year-end(set)	5363	5562	5683	5729	5800	5860
33 000  Hectares and Over	72	74	101	112	111	117
20 000-33 000  Hectares	76	99	141	169	169	170
Effective Irrigated Areas       (10 000 hectares)	2123.1	2249.9	2449.3	2524.4	2550.6	2641.9
33 000  Hectares and Over	604.7	631.4	788.3	938.1	971.4	1023
20 000-33 000  Hectares	189.6	244.4	344.0	408.4	405.7	408
Number of Reservoirs	83387	84775	85120	85153	85160	85108
Large-scale Reservoir	366	387	420	453	460	470
Medium-scale Reservoir	2499	2593	2704	2827	2869	2934
Small-scale Reservoir	80522	81795	81996	81873	81831	81704
Capacity of Reservoirs        (100 million cu.m)	4660	4797	5184	5658	5542	5624
Large-scale Reservoir	3397	3493	3842	4278	4147	4197
Medium-scale Reservoir	690	719	746	783	796	826
Small-scale Reservoir	573	585	594	597	599	602
Water-saving Irrigated Area (10 000 hectares)			1638.9	1944.3	2034.6	2133.8
Flooded or Waterlogged Area(10 000 hectares)	1933.7	2006.5	2098.9	2113.9	2119.8	2133.9
Area of Soil Erosion under Control	5300	6690	8096	8971	9200	9465
(10 000 hectares)
Improved Area of Saline-Alkaline Land	499.5	543.4	584.1	586.5	596.2	603.2
(10 000 hectares)
Total Length of Dikes                   (10 000 km)	22.0	24.7	27.0	27.8	27.7	27.7
Area of Land Protected by Dikes	3200.0	3060.9	3960.0	4387.5	4393.4	4412.0
(10 000 hectares)
a) The capacity of the large-scale reservoir is over 100 million cubic meters, while that of the medium-scale one is from 10 to 100 million cubic meters,
and that of the small-scale one is from 100 000 to 10 million cubic meters.