3.1 Climate

The air temperature of the reservoir areas of the Three Gorges in 2005 was continuously higher than the average. The annual average temperature (AT) of the central and western part was higher than that of usual level. While the annual air temperature of the eastern part was similar to the normal level. In winter and summer, the air temperature of the region was same as the normal level. But spring and autumn had relatively higher temperature. The average annual precipitation was close to the historical average with a little bit less in eastern part but same in other parts. The precipitation was less than the normal in winter and autumn but close to the normal level in spring and summer. During the wet season, there were not any large-scale and serious flood disasters. The average wind speed was slightly lower than the normal level. The annual average number of foggy days had an evident decrease. The average evaporation and relative humidity of the Three Gorges area were close to the normal level. The degree of acid rain was slightly heavier than in 2004. Major climate disasters include storms, floods and its secondary geological disasters such as landslides and mud-rock flow, droughts, strong winds, hails, strong convective currents and freezing weather.

Table 3-1 Monitoring results of meteorological items of each weather station of the Three Gorges Project area in 2005

Station name	AT	P	E	RH	AWS	NHS	NFD	NT
	(℃)	(mm)	(mm)	(%)	(m/s)	(h)	(d)	(d)
Chongqing	18.6	1020.3	1156.6	78	1.3	903.9	21	28
Changshou	17.6	1133.3	1092	82	1.2	1068.5	47	29
Fuling	18.4	1086.3	1162.8	74	0.7	1192.1	54	31
Fengdu	18.6	934.7	1253.4	72	1.1	1158.2	48	31
Zhongxian	17.8	1191.8	1124.2	79	1.2	1026.6	52	34
Wanzhou	18.4	1144.6	1219.4	76	0.7	1000.1	18	42
Yunyang	17.9	1086.1	1139.8	74	1.1	1381.1	38	35
Fengjie	18.3	893.2	1241.9	70	1.5	1158.8	4	22
Wushan	18.6	913.2	1379.9	66	0.6	1180.3	7	23
Badong	17.4	1032.8	1537.6	70	2	1431	38	34
Zigui	16.5	976.5	1161.8	75	1	1470.4	0	36
Bahekou	17.1	975.9	1189.3	75	1.4	1259.3	4	34
Yichang	17.5	1030.7	1400.3	76	1.1	1304.8	11	35

Note: AT stands for average temperature, RH stands for relative humidity; P stands for precipitation; E for evaporation; AWS for average wind speed; NHS for number of hours with sunshine; NFD for number of foggy days; NT for number of thunder storms.

The annual average precipitation of the Three Gorges Project area was 1037.1 mm in 2005, 85.0 mm less than the average, falling into the normal range. For spatial distribution, the precipitation of each weather monitoring station ranged from 893.2～1191.8 mm with the maximum precipitation occurred in Zhongxian County and the minimum in Fengjie. Compared with normal years, the precipitation amount of each monitoring station was normal except 10%～20% less recorded in Fengdu, Fengjie and Wushan. For time distribution of the precipitation, it had less rainfall in 2004/2005 winter and the autumn of 2005 with same amount of precipitation in spring and summer compared with that of normal years. The precipitation of the project area had its peak in autumn with 252.2 mm, 90% more than the normal level of the same period. But the precipitation of January and September went down by 50%～60% compared with the historical average. The precipitation of other months remained the same level as the historical average.

Figure 3-1  Percentage gap to monthly average precipitation of the Three Gorges Project area in 2005

Figure 3-2  Gap to monthly average temperature of the Three Gorges Project area in 2005

The annual average temperature of the Three Gorges Project area in 2005 was 18.1℃, 0.3℃ higher than the historical average level. In spatial distribution, the annual average temperature of each representative station was a little higher than or close to the historical average. Among them, it was 0.5～0.6℃ higher than the historical average in Chongqing, Fengdu, Wanzhou, Fengjie, Wushan and Yichang. In the time distribution, the average air temperature of winter and summer was close to the historical average but a little bit higher in spring and autumn. The average air temperature in February and August in 2005 was lower than the historical average of the same month, especially in August, 2.4℃ lower than the normal. However, the average air temperature of April, June and September was higher than the historical average, especially in September, 1.8℃ higher than the normal. The average air temperature of other months of 2005 was close to the historical average.

The wind of the project area in 2005 was not strong with the average wind speed being 1.1m/s, down by 0.2m/s compared with the normal level. The average wind speed of each representative weather station ranged from 1.0 to 2.0 m/s except Fuling, Wanzhou, Wushan and Zigui stations with around 0.7 m/s.

The annual average foggy days of the project area in 2005 was 28.3 days, 4.5 days less than in 2004 and 9.9 days less than the historical average. 2005 is the year with the least foggy days since 1979. In time distribution, winter had most foggy days, followed by spring, autumn and summer. The foggy days in the winter, summer and autumn of 2005 were less than the historical average but was same in the spring. In spatial distribution, there were more foggy days in the western part than in the eastern part. And 31.3 more foggy days occurred in Yunyang and 0.9 days more in Badong. The former had nearly 5 times more than the normal years. In other stations, there were 0.3 ~ 34.6 less foggy days compared with the normal level. Among them, there was the biggest reduction of goggy days in Wanzhou. The number of heavy foggy days of Chongqing, Wanzhou and Yichang was less than 50% of the normal. And the total number of foggy days of Fengjie was less than 1/6 of the normal level.

In 2005, the annual average relative humidity of the Three Gorges area was 74%, down by 2 percentage points than the historical average. It increased from the east to the west. Compared with normal years, Zigui had 4% increase in relative humidity, while other regions basically kept the same or being less. Among them, Fengdu had 9% decline, Fuling went down by 7% and Wanzhou by 6%. The annual average evaporation of the project area in 2005 was 1239.1 mm, close to the historical average. The regional distribution of the evaporation was big in the east and small in the west. From Wushan to Yichang, The annual average evaporation ranged from 1379.9 to 1537.6 mm with other regions between 1092.0 to 1253.4 mm. Chongqing, Fengdu, Zhongxian and Wanzhou had 10% ~ 20% more annual evaporation compared with the historical average. But Yunyang and Zigui had 10% less. Other weather stations basically had normal evaporation level.

In 2005, the average pH value of the precipitation of 6 monitoring stations was 4.54, 0.13 down compared with that of 2004. This falls into the normal acid rain value and being the lowest value since 1999. The pH value of Wanzhou, Dengjie and Badong was the lowest in the past 7 years, indicating relatively severe acid rain phenomenon.

Major climate disasters of the project area in 2005 were storms and floods as well as secondary geological disasters resulting from floods such as landslide and mud-rock flow, drought of the eastern region in late spring and early summer, drought of western region in summer, gale, hail, strong convective current like gale and hail as well as the freezing weather of eastern region in late winter and early spring.

Storms and floods: Local storms and floods mainly occurring during June ~ September imposed some life and property losses in 2005 but less than that of 2004. The worst storm occurred during July 8-10 in northeast of Chongqing, Yichang and Enshizhou of Hubei Province, which lead to landslides in many places and the highest peak of Jianglingjiang River since the wet season with 380 million RMB direct economic losses.

Drought: The precipitation of most areas of Yichang went down by 20% ~ 50% from January to June of 2005, causing relatively severe spring-summer draught. In particular, each area of the city experienced the abnormal "Kongmei" phenomenon from mid June to early Junly dominating by fine weather with high temperature, leading to rapid spread and worsening of the draught. Among them, Yichang city, Yiling District, Dangyang, YuanAn and Changyang had serious draught. According to primary estimate, this draught caused 280 million yuan direct economic losses of Yichang City, 250 million of which was direct economic losses in agriculture. In addition, Youyang, Xiushan, Pengshui, Jijiang and Fuling of Chongqing Municipality suffered evident reduction of rainfall from early June to Early July with obviously higher temperature, leading to summer draught at different degree. According to statistics, summer drought of Chongqing caused direct economic loss of 190 million yuan RMB.

Gales and hails: The frequency of gales and hails increased compared with that of 2004, causing heavier economic losses. According to primary estimate, more than 90 county-times of the Three Gorges Reservoir areas were hit by local strong convection current weather such as gales and hails, leading to direct economic losses of 1.15 billion yuan.

Low temperature and freezing weather: Part of the Three Gorges areas experienced low temperature and freezing weather in late winter and early spring. The east part of the Three Gorges areas was experiencing continuous weather of low temperature with rains or snows during Feb. 1~19, this has been the longest such weather in February since 1964. The temperature of some counties and cities of Yichang hit the lowest record of the same month over the past 40 years. 

3.2 Terrestrial Plants in the Reservoir Area

The plant species of the Three Gorges Reservoir areas in 2005 remained the same level as that of 2004. There were 6,088 vascular plants in the project area, which belong to 208 families and 1,428 genuses. The forests of the Three Gorges Reservoir areas fall into 76 formations belonging to 15 formation groups. There were 26 formations of shrub vegetation, which were classified into 5 formation groups. There were 17 formations of grass vegetation, which were classified into 2 formation groups.

There were 56 precious, rare and endangered plant species in the Three Gorges Reservoir areas under national conservation program. Among them, 4 were listed as Class I, 23 as Class II and 29 Class III, accounting for 7.1%, 41.1% and 51.8% respectively. There was no obvious vertical distribution pattern for the precious, rare and endangered plant species in the Three Gorges Reservoir areas, which scattered in many habitats at 200~2700 m elevation. Most of them were distributed in forests or lived under trees. Human activities are one of major threats to those precious, rare and endangered plant species.   

3.3 Terrestrial Wildlife in the Project Area

The findings of 1999~2005 investigation show that 194 species of terrestrial vertebrates live in the downstream valley of the Longhe River, first tributary of the Yangtze River. Among them, 3 species are the first-class national protected animals and 16 are second-class national protected animals. The breeding nests of 5 species of first and second class national protected animals such as Aquila chrysaetos, Hieraaetus fasciatus, Ketupa flavipes, Falco peredrinus and Falco tinnunculus are found in this region.

The investigation carried out in 2005 indicates that there are about 80 Presbytis francoisi that are first-class national protected animal under Special National Protection Program. They mainly distribute in the Furongjiang Valley bordering Wulong County and Pengshui County. There are 5 baby monkeys in the two Presbytis francoisi families under the track investigation of the current year. Among the two families, the members of the one living from Xuanba to Longdong waterfall increase from 6 to 8. And the members of the other family living from Tiaotang to Baichahe have increased from 10 to 13.

The investigation of water birds along the main stream of the Yangtze River and its main tributaries carried out in January of 2006 discovered large amount of nests of Riparia riparia at the alluvial bank of the Daning River in Wushan County. Riparia riparia is a kind of water-front habitat bird. Most Riparia riparia live at the bank of 139 m water table of the tail water of Dachang Town. However, after the impoundment of the Three Gorges Reservoir, 80% of the breeding places of Riparia riparia were inundated. There were only two breeding places left at the 145~160 m places, about 1,100~1,300 nests. With the completion of the Three Gorges Project and the impoundment, the habitat of Riparia riparia remain a focus of concern.

3.4 Fishery Resources and Environment

3.4.1 Fishery resources

The total fishing amount of the Three Gorges Reservoir, waters downstream the huge Dam, Dongting Lake, Boyang Lake and river mouth area in 2005 was 64,000 tons, similar to that of 2004. The fish fry flow of the "Four native fish species" at Jianli Cross-section and Wuxue Cross-section downstream the Dam continuously declined. The resources of parent crab and coilia mystus went up by different degree. But the resource of the output of eel fry in estuary area had some decline.

● Reservoir areas

The total fishery catch of the Three Gorges Reservoir in 2005 was 1,820 tons, 23% down compared with that of 2004. If we calculated the catch of individual species in the light of species composition in the reservoir, 340 tons were silver carp, 280 tons were bronze gudgeon, 219 tons were large mouth bronze gudgeon, 190 tons were catfish, 164 were pelteobagrus fulvidraco，151 tons were carp and 69 tons grass carp.

The monitoring results of fishing catch showed that seven species including large mouth bronze gudgeon, bronze gudgeon, silver carp, pelteobagrus fulvidraco, carp, catfish and grass carp accounted for 78% of the total fishery catch and were major commercial species of the Three Gorges Reservoir waters. However the size of large mouth bronze gudgeon and catfish was still relatively small and their age was rather young. Among the catch, 85% of large mouth bronze gudgeon and 79% of catfish were only one-year old.

● Waters downstream the Dam

The total fishery catch of the waters downstream the Three Gorges Dam in 2005 was 1,970 tons, a reduction of 6% compared with that of 2004. Among them, the catch of catfish was 542 tons, bronze gudgeon 406 tons, carp 301 tons, pelteobagrus fulvidraco 177 tons and the"four major local species"168 tons.

The catch monitoring results showed that bronze gudgeon, catfish, carp and pelteobagrus fulvidraco accounted for 72% of the total catch, which were still the major commercial fish species in the waters downstream the huge Dam.

● Spawning sites of the "Four Major Local Fishes"

The fish fry runoff of the "Four major local fishes" at both the Jianli Cross-section and Wuxue Cross-section was very low during May ~ June of 2005. It went down to 105 million, only 4.2% of the baseline figure before the impoundment, hitting the record low. The fish fry runoff of the "Four major local fishes" of Wuxue Cross-section was 716 million.

● Dongting Lake

The total catch of Dongting Lake was 23,600 tons in 2005, a reduction of 9% compared with that of 2004. Among them, 11,800 tons came from the east Dongting Lake, 6,900 tons from the south Dongting Lake, 4,900 tons from the west Dongting Lake, accounting for 50.0%, 29.2% and 20.8% of the total respectively.

There were 45 spawning grounds for carp and crucian with total area of 263 km², similar to that of last year. 13 of them were in the east Dongting Lake with an area of 132 km²; 26 in south Dongting Lake with an area of 59 km², 6 of them in the west Dongting Lake with an area of 72 km². The population of carp spawning communities were 15,900 weighing 267 tons, down by 9.1% and 9.8% respectively compared with that of last year. A total of 4.618 billion eggs were produced, down by 8.3% compared with that of 2004. The population of egg-laying crucian carps was 405,000 weighing 108 tons, producing 4.063 billion eggs, all similar to that of 2004.

There were 34 feeding sites in the Dongting Lake with a total area of 686 km². 13 of which were in eastern part of the Dongting Lake with an area of 415 km², 16 in southern part of the Dongting Lake with an area of 98 km², and 5 in eastern part of the Dongting Lake with an area of 173 km². The species of fish in those feeding sites were mainly carp, crucian, catfish, pelteobagrus fulvidraco, the "four major local fishes", bighead and bream. The fish population in the Lake is 5.532 billion, 4% down compared with that of the last year.    

● Boyang Lake

The total fish catch was 36,000 tons in Boyang Lake in 2005, 12% up than that of 2004. There were 33 spawning grounds for carps and crucians in the lake with an area of 321 km², up by 39.6% compared with that of the last year. A total of 4.25 billion eggs were produced, rise by 18.7% compared with that of the last year.

The area where fish could seek feed was 520 km² in the Lake, up by 20.9% compared with that of the last year. It was mainly distributed in the central and southern part of the Lake. The type of fish in the Lake were mainly carp, crucian, black carp, grass carp, silver carp, bighead, mandarin fish and catfish.

● Estuary Area

In 2005, the catch period of parent Chinese turtle crabs and eel was longer than that of 2004. The total catch days was less than in 2004. The catch period of coilia mystus was shorter than in 2004 but with same operation days.

The average catch of coilia mystus and parent Chinese turtle crabs per ship during the catch season was 4789.5 kg and 262.2 kg respectively, increase by 44.64% and 284.46 respectively. The total catch of the season was 814.2 tons for parent Chinese turtle crabs and 10,646.3 kg for coilia mystus, up by 8.8% and 482.82% respectively. Per ship catch of ell fry during the catch season was 15,615, down by 8.60% and the total catch of eel fry of the entire season reached 27.716 million, down by 22.31% compared with that of the last year.

3.4.2 Fishery Environment

In 2005, the authority established a total of 7 monitoring stations (Yibin, Banan, Wanzhou, Jingzhou, Yueyang, Hukou and Hekou) at the mainstream of the Yangtze River, Dongting Lake, Boyang Lake and Estuary Area and carried out environmental monitoring on major fishery waters of the Yangtze River basin and conducted water quality assessment in line with Standards for Fishery Water Quality (GB11607－89) . For the items not covered by the Standard, assessment was carried out according to the function class assessment of relevant water functions stipulated in Environmental Quality Standard for Surface Water. The findings indicated that the overall water quality of major fishery waters of the Yangtze River Basin was good in 2005 and could basically meet the requirements for the growth and reproduction of fishes. However, some waters were subject to pollution at some degree and major pollutants were petroleum, copper, total nitrogen and total phosphorus.

The water quality of the fishery waters of the upstream of the Yangtze River became better than in 2004 with evident reduction of the monitored concentration of petroleum and zinc. Major pollutant was copper, and permanganate index and zinc level exceeded the standard, too. Standard exceeding rate of copper concentration of the waters of Yibin during winter, fish breeding and growth (fattening) periods was 100%, and the standard exceeding rate of permanganate index during fish growth period was 50%. Standard-exceeding rate of copper concentration of the waters of Banan was 100%, so was zinc level during fish growth period. In Wanzhou waters, the standard-exceeding rate of copper concentration was 100%, too.

The water quality of the fishery waters of the mid-stream of the Yangtze River became better than in the last year with major pollutants being petroleum, total nitrogen and total phosphorus, etc.  In Guanyinsi water area of Jingzhou, all monitored pollutants did not exceed the standard during winter, but the concentration of petroleum in 66.7% samples went beyond relevant standard in breeding period. During the fattening period, 16.7% of the non-ionic ammonia sample, 83.3% of copper samples and 33.3% of petroleum samples exceeded relevant standard. In Zhicheng water area of Jingzhou, all monitored pollutants did not exceed relevant standard, and petroleum pollution went down as compared with last year. In Yueyang water area, total nitrogen level of 100% samples exceeded relevant standard during winter, fish breeding and growth periods, and total phosphorus level and petroleum level of 100% samples taken during fish fattening period went beyond relevant standards. In Hukou water area, copper-concentration exceeding environmental standard rate was 100% during egg-laying period and 66.7% during winter and fattening period. Compared with last year, petroleum and non-ionic ammonia pollution enjoyed a remarkable reduction.

In May and June, the concentration of petroleum of 8.3% water samples and cooper level of 4.2% samples taken from the egg-laying places of the "four major local fishes" exceeded relevant standard. The monitored value of copper and petroleum levels of individual monitoring stations had some rise compared with that of the last year. In November, all the monitored pollutants of the egg-laying grounds of Chinese sturgeon in water area of Yichang met environmental standard. The monitored level of petroleum had an evident reduction compared with that of the last year.

Major pollutants in fishery waters of Dongting Lake were total nitrogen (TN) and total phosphorus (TP). Copper pollution was lessened compared with in 2004. TN level of 75.0% water samples and TP level of 91.7% of water samples taken in winter exceeded environmental standard. During egg-laying period, TN and TP of 100% water samples went beyond the standard, and the concentration of 10% water samples exceeded relevant standard. During fish fattening period, the concentrations of non-ionic ammonia and petroleum of 20% samples went beyond relevant standard, and the TN level of 90% samples and TP level of 100% samples exceeded relevant standards.

Major pollutants in fishery waters of Boyang Lake was total phosphorus (TP), its pollution worsened compared with that in 2004. While the pollution caused by non-ionic ammonia had some reduction. In 100.0% of the water samples taken during fish egg-laying, fattening and winter periods, TP concentration went beyond relevant standard. The concentration of copper of 66.7% samples taken during winter and 33.3% samples taken during fattening period went beyond the standard.

For the fishery waters of Hekou Area (estuary) of the Yangtze River, standard exceeding rate of petroleum, TN and non-ionic ammonia was 33.3%, 100.0% and 16.7% respectively during the catch season of ell fry. During the catch season of coilia mystus, volatile phenol and copper concentration of 16.7% water samples exceeded relevant standard, and TN concentration of 100.0% of samples went beyond relevant standard. During the catch season of parent Chinese turtle crabs, zinc and TN concentrations of 100.0% of the water samples went beyond the standard.

3.5 Unique Fishes and Rare Aquatic Animals

3.5.1 Unique fishes in the upper reaches of the Yangtze River

In 2005, monitoring work was carried out at such places as the mid reaches of Jinshajiang River, Lijiang River section, Yongsheng section, Panzhihua section, Yibin section, Hejiang section, lower reaches of Wujiang River, Wanzhou section and Yichang section, a total of 117 species (sub-species) of fishes were collected, including 26 unique fishes in the upper reaches of Yangtze River.

Judging from the species composition of the catch, unique fishes took a big proportion in each section of the mid reaches of the Yangtze River. In Yongsheng section, Lijiang section and Panzhihua section of the mid reaches of Jinshajiang River, though fish species were not many, unique species took up relatively big proportion. Among 13 fish species caught at Yongsheng section, 6 were unique species, taking up 46.2%. All 6 species of fish caught at Lijiang section were unique species. Among 25 fish species caught at Panzhihua section, 8 were unique species, accounting for 32%. In Yibin section of the lower reaches of the Jinshajiang River, 9 of 44 fish species caught were unique species, accounting for 20.5%. 51 species of fish were caught in Hejiang section of the upper reaches of the Yangtze River, 14 of which were unique species, taking up 27.5%. Among 48 species of fish caught in the lower reaches of Wujiang River, the biggest tributary at the right of the Yangtze River, 10 were unique species, taking up 20.8%. In Wanzhou section of the Three Gorges Reservoir area, 44 species were caught, 8 of which were unique species, accounting for 18.2%. In Yichang section downstream the Three Gorges Dam, 65 species of fish were caught, 6 of which were unique species, taking up 9.2 of the total.

Judging from the size, weight, gender ratio and age structure, unique fish resources, which were the main fishery target, showed some trend of younger age and smaller size. For example, the fish population of large mouth bronze gudgeon of Yichang section downstream the Dam was dominated by the 3~6 year's old with insufficient amount of 1~2 year's old fish reserve. The weight and amount of fish catch showed that the proportion of unique species of Wanzhou section and Yichang section had some decrease compared with that of past years.

Six new species of fish including minnow, Ictalurus punctatus, black bullhead, Micropterus salmoides, Protosalanx hyalocranius and bluntnose black bream were discovered in the Three Gorges Reservoir areas, which have not been caught before. They probably were individual fish escaping from fish farm. Among them, the former four were introduced from foreign countries. The last two species do not have their natural habitat in the Three Gorges Reservoir areas. Therefore, whether these exotic fish can have natural reproduction and impose any negative impacts on native fish population requires further study.

3.5.2 Rare and precious fish species

In 2005, the spawning sites of Chinese sturgeon (Acipenser sinensis) remained in the river section between Miaozui and Gezhou Dam about5.5 km, most eggs were laid between the phosphorus fertilizer plant and Miaozui, mainly distributed the right side of the mainstream of the Yangtze River. Downstream Miaozui, the section between Mojishan to Wulongjiang and Huyatan were not found egg-laying by Chinese sturgeon. There was only once egg-laying occurred on November 9 with the amount about 6,064,000. It is estimated that 10 female Chinese sturgeons had produced eggs.

Sonar detection indicated that Chinese sturgeons distribute between Gezhou Dam to Gulaobei section, concentrating between the Dam and Miaozui with 12 fish detected. It is estimated that the breeding population of Chinese sturgeon in 2005 was about 235 before egg-laying and 157 after egg laying activities. This amount had some increase compared with that of the last year.

The appearance and staying period of young Chinese sturgeons at the river month of the Yangtze River ranged from May to August, mainly occurring in the waters between Tuanjiesha of the east beach of Chongming and Dongwangsha. During June ~ August, Young Chinese Sturgeons Protected Area at Chongming Island of Shanghai received 298 young Chinese sturgeons accidentally caught by fishermen, it is estimated that 2 of which were not from natural reproduction.

In 2005, there was no accidental catch of Chinese sturgeons in the waters from the mid and lower reaches of the Jinshajiang River to the river mouth of the Yangtze River. On June 30, one young Chinese sturgeon was accidentally caught at Yichang section. In autumn, one adult Chinese sturgeon was caught at Yichang downstream of the Gezhou Dam; 12 Myxocyprinus asiaticus were caught by accident between Wanzhou and Yichang section, one caught in Wanzhou was returned to the Yangtze River, another 11 caught between Zigui section and Zhijiang section were artificially bred in Yichang for artificial reproduction. There was record of accidental catch of rare and precious fish species in other sections of the Yangtze River.

3.6 Agricultural Ecology

Surveys were conducted in 181 towns and villages of 19 counties (cities) in the Three Gorges Reservoir areas in 2005, the same as that of the previous year.

3.6.1 Ecological environment of the farmland

The survey results showed that environmental pressure on the ecology of farmlands in the reservoir area in 2005 was increasing with slowdown in such activities as upgrading slope land into terrace farmland and "grain for green". With continuous reduction of arable land area and the total sowing area of cops, the contradiction between many farmers and less land resources became more striking. Agricultural production kept its priority on grain crops and its percentage in total agriculture produce enjoyed some increase.

In 2005, the total area of arable land in the Reservoir area was 192,110 ha, 3.6% less than the previous year. Among them, 16.5% of the land had the slope more than 25o. There were 393,480 ha forest land, down by 1.5% compared with that of 2004. There were 61,760 ha orchard, up by 10.1%. Tea garden area was 8850 ha with a reduction of 3.3%. A total of 25,320 ha farmland with the slope more than 25o had been restored to its original forest or grassland.

The multiple crop index was 253.0. The total agricultural sowing area was 502,350 ha, down by 0.1% compared with that of the last year. Among the total sowing area, 371,090 ha were for grain crops and 131,260 ha for economic crops, taking up 73.9% and 26.1% of the total respectively. Compared with the last year, the percentage of grain crops went up by 2.5 percentage points.

There were 81,330 ha paddy fields and 110, 780 ha dry land, accounting for 42.3% and 57.7% of total arable land. The percentage of paddy fields went up by 0.4 percentage points compared with that of 2004. As to the farming system, paddy fields were dominated by two-crop system, accounting for 59.1% of the total, down by 0.9 percentage points than that of the previous year. Dry land mainly practiced the three-crop system, accounting for 62.2.0% of the total, up by 6.2 percentage points compared with that of 2004.

3.6.2 Rural energy

In 2005, the energy structure in rural areas of the Three Gorges Reservoir area continued its improvement. Energies for rural households were still mainly derived from direct burning of firewood and stalks while the energy percentage from small hydro-power stations and mash gas generation kept on rising. Among all kinds of rural energy, direct burning of firewood and stalk constituted the largest proportion at around 71.8%, followed by small coal pits being 20.4%, marsh gas 5.6%, and small hydro-power stations 2.2%. Compared with the previous year, direct burning of firewood and stalks went down by 4.6 percentage points, while the percentage of small coal pits, small hydropower stations and marsh gas increased by 4.0, 0.5 and 0.1 percentage points respectively.

With more input of the State in the development of ecological environment of the Three Gorges Reservoir, especially the development of eco-village based on marsh gas utilization and widespread application and extension of highly efficient ecological agriculture technique, the application of march gas enjoyed rapid development. In 2005, 1.367 million rural households of the Three Gorges Reservoir areas utilized marsh gas with the development of 81,804 marsh gas generating pits and annual output of 32.492 million m³ of such gas, up by 0.7%, 1.6% and 8.4% respectively as compared with that of 2004.

3.6.3 Crop plant diseases and insect pests

The total area affected by plant diseases and insect pests in 2005 had certain drop compared with that of 2004. Plant diseases and insect pests prevention and control rate enjoyed a dramatic rise. But the actual losses were alleviated, and the area involved in prevention and control of plant diseases and insect pests increased with some more damages and actual losses. There was no outbreak or great imperil of certain plant disease or insect pests, and no new plant disease or insect pest was observed.

The total cropland area suffering from plant diseases and insect pests was 479,880 ha·times, 308,770 ha·times of which were affected by insect pests, and 171,110 ha?times by plant diseases, down by 31.4%, 27.6% and 37.2% respectively compared with that of 2004.

The area involved in the prevention and control of plant diseases and insect pests reached 452,150 ha·times, among which 291,390 ha·times were for the prevention and control of insect pests and 160,760 ha·times for the prevention and control of plant diseases, down by 24.5%, 20.2% and 31.1% respectively in comparison with the previous year. The prevention and control rate for plant diseases and insect pests was 94.2%, up by 8.6 percentage points. The actual loss of grain production amounted to 44,823.4 tons, 142,385.6 tons of potential grain losses were averted, up by 11.9% and 3.3% respectively compared with that of the previous year.

Table 3-2  Statistics on the occurrences of major plant diseases and insect pests in the Three Gorges Reservoir area in 2005

Types of plant diseases and insect pests	Area affected	Area for prevention and control	Losses recovered	Actual losses	Degree
	(100 ha·times)	(100 ha·times)	(t)	(t)
Paddy stem borer	835.89	862.25	18686.05	6576.42	Heavier than medium
Piricularia oryzae	236.94	300.24	28830.08	9119.52	Heavier than medium
Corn northern leaf blight and corn southern leaf blight	169	118.3	1300.03	808.97	Medium
Osmotin HarpinEa	155.9	106.9	6383.54	3144.97	Heavier than medium
Corn sheath blight	345.2	299.1	7206.96	2034.15	Heavier than medium
Rat	1290.91	750.98	19273.01	17072.11	Medium

3.7 Geological Disasters in the Reservoir Area

3.7.1 Earthquakes

In 2005, a total of 905 earthquakes measuring at ML≥0.0 occurred from the head to the middle areas of the Three Gorges Reservoir (from 108°20′ to 112°00′ east longitude and 29°55′ to 31°45′ north latitude). Among these earthquakes, 431 quakes measuring at 0.0≤ML＜0.9, 405 at 1.0 ≤ML＜1.9, 67 at 2.0≤ML＜2.9 and two at 3.0≤ML＜3.9. The largest earthquake, which measured at ML＝3.5, occurred in Dongxiangkou, Badong County at 15:30, September 22, 2005.

After the second-stage impoundment, slight earthquakes in the Three Gorges Reservoir areas basically concentrated on Wushan-Badong-Zigui-Changyang region. The quake intensity remained at the normal low level except evident increase of the frequency.

Figure 3-3 Earthquake occurrences from the head to central parts of the Reservoir area

3.7.2 Collapses, landslide and mud-rock flow

● Monitoring and early warning

During 2005, most places subject to collapses and landslide enjoyed relative good stability. Professional monitoring found that there were 22 collapses and landslide with evident distortion at site, accounting for 17% of the total professional monitored results. Among them, 6 occurred at the Three Gorges Reservoir areas in Hubei Province and 16 in Chongqing Municipality. The authority issued early warning to 5 of the above collapses and landslides, facilitating the timely evacuation of the local communities under threat. 18 collapses and landslides were found by local non-professional monitoring, prevention and early warning system, this has ensured the safety of more than 1000 local residents and their properties. Among them, the landslide at Bazimen at the right bank of the river mouth of the Xiangxihe River, Zigui County of Hubei Province was quite typical with a volume of 5.1 million m³. The sliding materials were Quaternary loose rock and earth with the bed being Jurassic sandstone and mudstone. After the establishment of the Gezhouba Water Control Project, the impoundment has submerged the front with obvious deformation of the landslip. When the impoundment of the Three Gorges Reservoir reached 139m, the lower part of the landslip was inundated with further reduction of stability. In order to ensure the safety of local communities and road in vicinity of the landslide area, a comprehensive professional monitoring network including GPS absolute displacement, deep displacement of drill tiltmeter, Slope thrust and the dynamics of groundwater has been set up and a mass monitoring and preventing system put in place with remarkable achievements. After 10 households were removed in 1998 to avoid the potential disaster, local government arranged emergency removal of 170 people of another 49 households in response to early warning, this has ensured the safety of the lives and properties of local communities.

● Prevention and control projects

In 2005, the Geological Collapse and Landslide Disaster Prevention and Control Project (phase III) of the Three Gorges Reservoir area entered the stages of overall survey, design, and the review, assessment and approval of project outcomes. These projects included emergency treatment of 195 collapse and landslide sites (65 in Hubei, 130 in Chongqing), emergency repair of the collapses of 227 sections of bank (bank rebuilt) with a total length of 92.8 km (67 sections in Hubei with a length of 26.5 km, 160 sections in Chongqing with a length of 66.3 km) and removal and protection project for steep bank slope, which have laid a good foundation for the implementation of the project.     Meanwhile, Hubei Province, Chongqing Municipality and each district and county of the reservoir area began the repair, maintenance and outcome supervision on the finished second-stage prevention and control project and carried out the final check and approval of such projects at district (county), province (big city) and State level. The check and approval authority considered that all the geological disaster prevention and control projects are playing an important role in environmental protection and ecological conservation with good effects.