13-10  Irrigation, Reservoirs, Flood Prevention, Water and Soil Conservation and Improvement of Saline-Alkaline Land
Item	1990	1995	2000	2004	2005	2006
Number of Irrigated Areas at year-end    (set)	5363	5562	5683	5800	5860	5894
33 000  Hectares and Over	72	74	101	111	117	119
20 000-33 000  Hectares	76	99	141	169	170	166
Effective Irrigated Area      (10 000 hectares)	2123.1	2249.9	2449.3	2550.6	2641.9	2802.1
33 000  Hectares and Over	604.7	631.4	788.3	971.4	1023	1052
20 000-33 000  Hectares	189.6	244.4	344.0	405.7	408	409.2
Number of Reservoirs	83387	84775	85120	85160	85108	85849
Large Reservoir	366	387	420	460	470	482
Medium-sized Reservoir	2499	2593	2704	2869	2934	3000
Small Reservoir	80522	81795	81996	81831	81704	82367
Capacity of Reservoirs        (100 million cu.m)	4660	4797	5184	5542	5624	5842
Large Reservoir	3397	3493	3842	4147	4197	4379
Medium-sized Reservoir	690	719	746	796	826	852
Small Reservoir	573	585	594	599	602	611
Water-saving Irrigated Area (10 000 hectares)			1638.9	2034.6	2133.8	2242.6
Flooded or Waterlogged Area (10 000 hectares)	1933.7	2006.5	2098.9	2119.8	2133.9	2137.6
Area of Soil Erosion under Control	5300	6690	8096	9200	9465	9749
(10 000 hectares)
Improved Area of Saline-Alkaline Land	499.5	543.4	584.1	596.2	603.2
(10 000 hectares)
Total Length of Dikes                   (10 000 km)	22.0	24.7	27.0	27.7	27.7	28.1
Area of Land Protected by Dikes	3200.0	3060.9	3960.0	4393.4	4412.0	4548.6
(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.