Environmental impacts of hydroelectric projects on fish resources in China

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<ul><li><p>REGULATED RIVERS: RESEARCH &amp; MANAGEMENT, VOL. 12, 81-98 (1996) </p><p>ENVIRONMENTAL IMPACTS OF HYDROELECTRIC PROJECTS ON FISH RESOURCES IN CHINA </p><p>YIGUANG ZHONG AND GEOFF POWER* Department of Biology, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1 </p><p>ABSTRACT </p><p>China has embarked on a programme to vastly expand its hydroelectric generating capacity and this is certain to alter its freshwater and anadromous fish communities. To provide some insight into the direction and consequences of the likely changes, four (&gt; 250 000 kW) existing facilities were selected for review. The Gezhouba Dam, on the Changjiang River, commissioned in 1981, is a low-head run of the river facility. The Xinanjiang Dam (1959) is a high-head dam and the Fuchunjiang Dam (1968) is a low-head, run of the river dam, both sited on the Quiantang River. The Danjiangkou Dam (1968) is a high-head dam in the Han River, a tributary of the Changjiang River. Impacts on fish were classified as those caused directly by the structures, those resulting from changes in physical and chemical factors in their environment and those induced through biotic changes in their habitat. </p><p>Migrations of anadromous and semi-migratory fish were blocked by the Gezhouba Dam, although some species adapted to the new environment by reproducing downstream. Below the Xinanjiang and Danjiangkou dams spawning was delayed 20-60 days by lower water temperatures. Reduced water velocities and less variable discharges caused spawning grounds below the dams to be abandoned. Marked changes in the hydrological regime caused the extinction of Macrura reevesii, a highly valued fish, in the Qiantang River. The fish communities in the Qiantang estuary were affected by the regulated discharge. Freshwater species fell from 96 to 85, whereas marine species increased from 15 to 80. Loss of habitat eliminated torrential habitat species from the areas inundated by Xinanjiang and Danjiangkou Reservoirs; lentic fish replaced lotic species and now dominate the reservoir fish communities. The expanded aquatic habitat was beneficial for fishery production. Catches from the two reservoirs continue to increase 20 years after impoundment, but are supported by extensive artificial propagation and stocking. There is no doubt that, when the expansion of Chinas hydroelectric facility network is complete, the fish communities in its rivers will be markedly changed. </p><p>KEY WORDS China; fisheries; hydropower </p><p>INTRODUCTION </p><p>In China, hydro power is usually considered a better source of energy than fossil fuels due to its low cost over the long term and lack of perceived environmental problems. Since the 1950s, approximately 62 000 hydro- electric projects have been constructed; most are small, &lt; 12 000 kW, and almost all the major rivers in the country are today regulated (Fang, 1993). </p><p>In recent years, the construction of hydroelectric projects has been further encouraged to meet the demand of the booming economy of the country. Some large, &gt; 250 000 kW, and medium-sized hydroelectric pro- jects have been finished and more projects are being planned, designed or are under construction in the major rivers. In Fujian Province, more than 40 large and medium projects are being designed and built in the 60992 km2, 584 km long Min River basin (Lian et al., 1987). In December 1994 construction started on the Three Gorges Project, Changjiang River (Yangtze), which will have a capacity of 18 200 MW and will be the largest hydropower station in the world (Lu, 1994). A number of other large projects will be developed later in the upper reaches of the Changjiang River (Chao et al., 1987). A 30-year plan for hydroelectric devel- opment in Sichuan Province, located in the upper reaches of the Changjiang basin, has been proposed (CRDI, 1989). According to this plan, a number of new hydropower stations will be constructed in the pro- vince, with a potential capacity of 35720MW by the year 2015. The Longtan Hydropower Station in </p><p>* To whom correspondence should be addressed </p><p>CCC 0886-9375/96/01008 1 - 18 0 1996 by John Wiley &amp; Sons, Ltd. </p><p>Received 25 February 1995 Accepted I7 July 1995 </p></li><li><p>82 Y. ZHONG AND G . POWER </p><p>I DANJIANGKOU DAM </p><p>0 t do N SCALE Km </p><p>HAN RIVER </p><p>QIANTANG RIVER </p><p>Figure I . Locations of the major hydroelectric dams discussed in the text. The black scale bars on the detailed maps represent 100 km </p><p>Guangxi is to be built soon (Dansie, 1995). The project is one of 10 hydropower stations planned for construc- tion along the Hongshui River and it will be the second largest in the country (China Daily, 17 February, 1994). In Chma the total capacity of large projects under survey, design and scheduled for construction in the near future and in the early 21st century will exceed 100 000 MW (Pan and Zhang, 1993). However, although hydro- electric projects play an important part in the economy and development of society, there are many environ- mental effects on fish and aquatic ecosystems which need to be considered (Brooker, 1981; Chen, 1984a; 1984b; 1985; Saltveit et af., 1987; Ward and Stanford, 1987). The tendency has been to neglect the ecological costs and emphasize only the economic benefits when making decisions about the hydroelectric developments. </p><p>This paper reviews the environmental impacts of hydroelectric development on fish in China. It describes the hydrological changes and the primary, secondary and tertiary impacts on fish. Four large hydroelectric projects in central and eastern China (Figure 1) were selected as the main focus of this review, namely the Xinanjiang, the Fuchunjiang, the Danjiangkou and the Gezhouba projects. These were chosen because the dams vary in location, height and effects on fisheries and they provide insights into the overall cumulative effect on fish resources of Chinas massive hydroelectric development plans. </p><p>DESCRIPTION OF THE RIVERS AND THE PROJECTS </p><p>Table I summarizes the main technical details of the four hydroelectric projects considered. A description of their setting and type of operation follows. </p><p>The Qiantang River (Figure 1) is a major river in Zejiang Province, with a length of 494 km. It flows from west to east through the north of the province before entering the East China Sea. Annual precipitation in the basin is 1500-2000 mm, half falling between June and August. The mean discharge before regulation was 1038m3 SKI, with 49% occurring during May to July (Chen et al., 1990). Four large and medium hydro- electric projects have been constructed on the river and its tributaries since the late 1950s. The Xinanjiang </p></li><li><p>X </p><p>P T</p><p>able</p><p> I. M</p><p>ain </p><p>tech</p><p>nica</p><p>l par</p><p>amet</p><p>ers o</p><p>f sel</p><p>ecte</p><p>d hy</p><p>droe</p><p>lect</p><p>ric p</p><p>roje</p><p>cts </p><p>3 s ar</p><p>eas </p><p>capa</p><p>city</p><p> ou</p><p>tput</p><p> he</p><p>ad </p><p>initi</p><p>al </p><p>heig</p><p>ht </p><p>leng</p><p>th </p><p>area</p><p>s sto</p><p>ra5e</p><p> ga $ </p><p>1784</p><p>0 2 </p><p>290 </p><p>56 </p><p>44</p><p>0c</p><p>! B 8 </p><p>Proj</p><p>ect </p><p>Riv</p><p>er </p><p>Dra</p><p>inag</p><p>e G</p><p>ener</p><p>atin</p><p>g A</p><p>nnua</p><p>l M</p><p>axim</p><p>um </p><p>Yea</p><p>r of</p><p> D</p><p>am </p><p>Dam</p><p> R</p><p>eser</p><p>voir</p><p> R</p><p>eser</p><p>voir</p><p>(1 O3</p><p> km</p><p>2) </p><p>(MW</p><p>) (W</p><p>H) </p><p>(m) </p><p>oper</p><p>atio</p><p>n (m</p><p>) (m</p><p>) (k</p><p>m2)</p><p> (1</p><p>o6m</p><p> ) </p><p>Gez</p><p>houb</p><p>a C</p><p>hang</p><p>jiang</p><p> 10</p><p>00 </p><p>2715</p><p> 13</p><p>.9 </p><p>27.0</p><p> 19</p><p>81 </p><p>70 </p><p>2561</p><p> 63</p><p> 15</p><p>80 </p><p>U </p><p>Dan</p><p>jiang</p><p>kou </p><p>Han</p><p> 95</p><p> 90</p><p>0 3.</p><p>88 </p><p>81.5</p><p> 19</p><p>68 </p><p>110 </p><p>2549</p><p> 74</p><p>5 17</p><p>450 </p><p>Xin</p><p>anjia</p><p>ng </p><p>Xin</p><p>anjia</p><p>ng </p><p>662.</p><p>5 1.</p><p>86 </p><p>84.5</p><p> 19</p><p>60 </p><p>105 </p><p>462 </p><p>580 </p><p>Fuch</p><p>unjia</p><p>ng </p><p>Qia</p><p>ntan</p><p>g 31</p><p> 29</p><p>7.2 </p><p>0.92</p><p> 17</p><p>.1 </p><p>1968</p><p> 48</p><p>MW</p><p>, meg</p><p>awat</p><p>ts; a</p><p>nd TWH, te</p><p>raw</p><p>att hours </p><p>z 00 </p><p>W </p></li><li><p>84 Y . ZHONG AND G . POWER </p><p>Dam is the largest. It was completed in October 1959 and is situated in the Xinan River, an upper tributary of the Qiantang River. The dam crest is 105 m as1 and it creates a reservoir of 580 km2 in which the water level fluctuates annually between 85 and l00masl. Discharge through the turbines is between 200 and 1000m3 s-'. The water transparency (Sechi disc readings) is normally 5 m. Fuchunjiang Dam, another large dam in the river, is situated on the main stem of the middle reach of the Qiangtang River, only 60 km below the Xinanjiang Dam. It was constructed in December 1968, with a controlled drainage area of 31 300 km2. The dam is a low-head, run of the river dam. The water level in the reservoir is normally 23 m as1 with an effective storage of 440 x lo6 m3, and the reservoir is regulated daily according to demand. The maximum discharge through the turbines is 2500 m3 s-'. </p><p>The Han River (Figure 1) is the largest tributary of the Changjiang River. The headwaters of the river are in the south of Shaanxi Province and it enters the middle reach of the Changjiang River at Wuhan, Hubei Province. The river is 1532 km long, with a drainage area of 173 621 km2. Annual precipitation in the basin is between 700 and lOOOmm, about 40% of which falls in July and August. Before dam construction, the mini- mum discharge was 250m3 sC1 in January and February and peak flows of 2300-3300m3 s f l occurred between July and September (Yu et al., 1981). The river section above Danjiangkou is called the upper reach, with a length of 890 km. The Danjiangkou hydro project, with a high-head dam, was finished in 1968. The reservoir formed by the dam is about 100 km long, 1000 km2 and is, at present, the largest reservoir in China. </p><p>The Changjiang River (Figure 1) flows from the Qing-Zhang Plateau in the west to Shanghai in the east to join the East China Sea. With a length of more than 6300 km it is the third largest river in the world and the longest in Asia. Its 1.94 x lo6 km2 drainage basin is the home for nearly half of China's billion inhabitants. The mean annual discharge in the Yichang section of the river is about 14 300 m3 s-'. The period June to October is the flood season when about 72% of the annual runoff occurs, with peak flows concentrated in July and August (Yu et al., 1985a). The Gezhouba hydroelectric project, 4 km above Yichang City, Hubei Province, was the first dam constructed on the main stem of the Changjiang River. It is a low-head, run of the river hydroelectric project and was completed in January 1981 and impounded in May 1981. The generating capacity is about 2700 MW, which makes it the largest generating station now operating in China. The maximum difference in water level between the reservoir and the river below the dam is 27 m. The project creates a reservoir with a length of 110-180 km and an area of 63 km2. Most of the reservoir is in steep- sided gorge areas and its width is only 300-1000m. </p><p>HYDROLOGICAL EFFECTS </p><p>The downstream hydrology is modified by the regulated discharge from operational hydroelectric projects. Factors affected inciude water temperature, water level, discharge and current velocity. </p><p>Water temperature After the Xinanjiang Dam was built on the Qiantang River in 1959, the mean water temperature below the </p><p>dam decreased from 19.0 to 13.5"C. Peak temperatures 2.5 km downstream from the dam decreased from 34.8 to 23.2"C and minimum temperatures increased from 1.9 to 6.3"C. The cooler discharge reduced water temperatures as far as the mouth of the Qiantang River, a distance of about 260 km (Li, 1987). In the Han River, water temperatures below the Danjiangkou Dam generally decreased by 4-6C from March to Sep- tember and increased by 4-6C from October to February (Yu er al., 1981). In contrast, water temperatures downstream from Fuchunjiang and Gezhouba Dams both low-head structures, did not change significantly after construction (Chao et al., 1989; Chen et al., 1990) (Table 11). </p><p>Downstream discharge Frequent and large variations in water levels in rivers are reduced after dam construction and discharge </p><p>regulation. Yu et al. (1981) reported that before Danjiangkou Dam was built, the lowest mean monthly water level in the middle reach of the Han River in July was 88.8masl and the highest level was 91-6masl. After construction, water levels varied from 88.6 to 89-6m. In the Qiantang River after the con- struction of the Xinanjiang Dam, water levels in the flood season over the spawning grounds were about 3 m </p></li><li><p>Tabl</p><p>e 11</p><p>. Mea</p><p>n m</p><p>onth</p><p>ly w</p><p>ater</p><p> tem</p><p>pera</p><p>ture</p><p>s (C</p><p>) in </p><p>river</p><p>s bef</p><p>ore </p><p>and </p><p>afte</p><p>r th</p><p>e co</p><p>nstr</p><p>uctio</p><p>n of</p><p> dam</p><p>s at v</p><p>ario</p><p>us lo</p><p>catio</p><p>ns in</p><p> Chi</p><p>na </p><p>Tim</p><p>e an</p><p>d pl</p><p>ace*</p><p> Ja</p><p>n Fe</p><p>b M</p><p>ar </p><p>Apr</p><p> M</p><p>ay </p><p>Jun </p><p>Befo</p><p>re X</p><p>Dt,$</p><p> A</p><p>fter </p><p>XD</p><p>t,S </p><p>Befo</p><p>re F</p><p>Dt,</p><p> A</p><p>fter </p><p>FDtT</p><p> Be</p><p>fore</p><p> DD</p><p>ll A</p><p>fter</p><p> DD</p><p>ll Be</p><p>fore</p><p> GD</p><p>** </p><p>Afte</p><p>r G</p><p>D**</p><p>7.0 </p><p>8.0 </p><p>8.4 </p><p>8.6 </p><p>8.4 </p><p>8.6 </p><p>9.0 </p><p>8.4 </p><p>5.2 </p><p>8.2 </p><p>8.3 </p><p>7.6 </p><p>9.6 </p><p>9.7 </p><p>9.0 </p><p>9.0 </p><p>12.5</p><p> 18</p><p>.4 </p><p>21.2</p><p> 26</p><p>.8 </p><p>11.8</p><p> 15</p><p>.5 </p><p>19-6</p><p> 22</p><p>4 11</p><p>.8 </p><p>15.5</p><p> 19</p><p>-6 </p><p>22.4</p><p> 11</p><p>.2 </p><p>17.1</p><p> 20</p><p>.6 </p><p>21.7</p><p> 14</p><p>.9 </p><p>15.2</p><p> 21</p><p>.5 </p><p>25.1</p><p> 14</p><p>.7 </p><p>18.4</p><p> 19</p><p>.0 </p><p>22.5</p><p> 13</p><p>.4 </p><p>17.8</p><p> 21</p><p>.0 </p><p>23.3</p><p> 11</p><p>.9 </p><p>16.9</p><p> 21</p><p>.2 </p><p>23.4</p><p>Jul </p><p>Aug</p><p> Se</p><p>p O</p><p>ct </p><p>Nov</p><p> D</p><p>ec </p><p>Mea</p><p>nann</p><p>ual </p><p>tem</p><p>pera</p><p>ture</p><p>30.9</p><p> 30</p><p>.5 </p><p>25.8</p><p> 20</p><p>.3 </p><p>15.2</p><p> 10</p><p>.5 </p><p>18.9</p><p> 4 </p><p>24-6</p><p> 24</p><p>.1 </p><p>22.4</p><p> 19</p><p>.3 </p><p>16.0</p><p> 11</p><p>.7 </p><p>17.0</p><p>z </p><p>24.6</p><p> 24</p><p>.1 </p><p>22-4</p><p> 19</p><p>.3 </p><p>16.0</p><p> 11</p><p>.7 </p><p>17.0</p><p> $ s 5 P </p><p>24.8</p><p> 22</p><p>.4 </p><p>22.8</p><p> 19</p><p>.9 </p><p>16.3</p><p> 11</p><p>.9 </p><p>17.2</p><p> 30</p><p>.6 </p><p>30.6</p><p> 26</p><p>.2 </p><p>17.0</p><p> 16</p><p>.2 </p><p>7.7 </p><p>18.2</p><p> 24</p><p>6 18</p><p>.7 </p><p>19.7</p><p> 19</p><p>.8 </p><p>14.8</p><p> 11</p><p>.0 </p><p>16-6</p><p> U</p><p>24.0</p><p> 25</p><p>.4 </p><p>22.9</p><p> 20</p><p>.3 </p><p>16.5</p><p> 11</p><p>.6 </p><p>17.7</p><p> 3 </p><p>25.4</p><p> 25</p><p>.5 </p><p>23.0</p><p> 19</p><p>.8 </p><p>16.4</p><p> 12</p><p>.6 </p><p>18.1</p><p> z !2 0 z &gt; </p><p>* XD</p><p>, Xin</p><p>anjia</p><p>ng D</p><p>am; F</p><p>D, F</p><p>uchu</p><p>njia</p><p>ng D</p><p>am; D</p><p>D, D</p><p>anjia</p><p>ngko</p><p>u D</p><p>am a</p><p>nd G</p><p>D, G</p><p>ezho</p><p>u D</p><p>am </p><p>2 t S</p><p>ampl</p><p>ing </p><p>site</p><p> for w</p><p>ater</p><p> tem</p><p>pera</p><p>ture</p><p> was</p><p> at t</p><p>he F</p><p>uchu</p><p>njia</p><p>ng r</p><p>eser</p><p>voir</p><p> bef</p><p>ore </p><p>cons</p><p>truc</p><p>tion </p><p>of th</p><p>e Fu</p><p>chun</p><p>jiang</p><p> Dam</p><p>. It w</p><p>as m</p><p>oved</p><p> bel</p><p>ow t</p><p>he d</p><p>am in</p><p> 196</p><p>8 </p><p>Dat</p><p>a fr</p><p>om C</p><p>hen ef </p><p>al. (</p><p>1990</p><p>). T</p><p>he d</p><p>ata </p><p>wer</p><p>e co</p><p>llect</p><p>ed b</p><p>etw</p><p>een </p><p>1960</p><p> and</p><p> 196</p><p>8 qD</p><p>ata </p><p>from</p><p> Che</p><p>n et</p><p> al. </p><p>(199</p><p>0). T</p><p>he d</p><p>ata </p><p>wer</p><p>e co</p><p>llect</p><p>ed b</p><p>etw</p><p>een </p><p>1968</p><p> and</p><p> 197</p><p>3 an</p><p>d be</p><p>twee</p><p>n 19</p><p>78 a</p><p>nd 1</p><p>980 </p><p>II Dat</p><p>a fr</p><p>om Y</p><p>u ef</p><p> al. (</p><p>1981</p><p>). T</p><p>he d</p><p>ata </p><p>wer</p><p>e co</p><p>llect</p><p>ed in</p><p> 196</p><p>2 an</p><p>d 19</p><p>74, r</p><p>epre</p><p>sent</p><p>ing </p><p>befo</p><p>re a</p><p>nd a</p><p>fter</p><p> dam</p><p> con</p><p>stru</p><p>ctio</p><p>n, r</p><p>espe</p><p>ctiv</p><p>ely </p><p>** D</p><p>ata </p><p>from</p><p> Cha</p><p>o ef</p><p> al. (</p><p>1989</p><p>). T</p><p>he d</p><p>ata </p><p>wer</p><p>e co</p><p>llect</p><p>ed b</p><p>etw</p><p>een </p><p>1977</p><p> and</p><p> 198</p><p>1 an</p><p>d be</p><p>twee</p><p>n 19</p><p>82 a</p><p>nd 1</p><p>984,</p><p> repr</p><p>esen</p><p>ting </p><p>befo</p><p>re a</p><p>nd a</p><p>fter</p><p> dam</p><p> con</p><p>stru</p><p>ctio</p><p>n, r</p><p>espe</p><p>ctiv</p><p>ely </p><p>* Data </p><p>from</p><p> Che</p><p>n et</p><p> al. </p><p>(199</p><p>0). T</p><p>he d</p><p>ata </p><p>wer</p><p>e co</p><p>llect</p><p>ed b</p><p>etw</p><p>een </p><p>1957</p><p> and</p><p> 195</p><p>9 </p></li><li><p>86 Y. ZHONG AND G. POWER </p><p>Table 111. Changes in downstream hydrological factors after dam construction </p><p>Parameter River Before dam After dam </p><p>Water level (elevation, m) Lowest Highest Difference in flood Season Lowest Highest </p><p>Winter Summer Percentage of annual flow May to June Lowest discharge (February) Highest discharge (July) </p><p>Velocity (ms-') Spawning grounds April-June </p><p>Discharge (m3 s-I) </p><p>Wan </p><p>Qiantang Changjiang </p><p>Han </p><p>Quiantang Changjiang </p><p>Qiantang Changjiang </p><p>88.8 91-6 4.08 </p><p>39.83 47.95 </p><p>250 2300-3300 </p><p>545 3406 </p><p>24 275 </p><p>1-1.5 0'89-1.77 </p><p>88.6 89.6 </p><p>1 -0 39.64 50.1 1 </p><p>750-900 1000- 1500 </p><p>27.1 4203 </p><p>39 200 </p><p>0.5 0.78-1.65 </p><p>lower (Chen et al., 1990; Zhu, 1992). There was no noticeable change in water levels in the Changjiang River after construction of the low-head Gezhouba Dam (Chao et al., 1989) (Table 111). </p><p>Reservoir storage is important in diminishingpeak flows. Chen et al., (1990) reported that discharge below the Xinanjiang Dam in the period May to July 1968- 1976 decreased from 54.5 to 27.1 % of the mean annual discharge. The peak discharge in the midd...</p></li></ul>


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