A review of water resources utilization and protection in Southwest China

CuiFang Wu, Steve Déry, WanCai Wu, XueBin Liu, JinHui Xiong, WenQi Gao

1. School of Agriculture & Forestry Economics and Management, Lanzhou University of Finance and Economics, Lanzhou, Gansu 730080, China

2. Department of Geography, Université Laval, Quebec City, G1V 0A6, Canada

3. Center of Teaching Guidance, Gansu Radio & TV University, Lanzhou, Gansu 730030, China

4. School of Economics, Lanzhou University of Finance and Economics, Lanzhou, Gansu 730080, China

A review of water resources utilization and protection in Southwest China

CuiFang Wu1*, Steve Déry2, WanCai Wu3, XueBin Liu4, JinHui Xiong4, WenQi Gao4

1. School of Agriculture & Forestry Economics and Management, Lanzhou University of Finance and Economics, Lanzhou, Gansu 730080, China

2. Department of Geography, Université Laval, Quebec City, G1V 0A6, Canada

3. Center of Teaching Guidance, Gansu Radio & TV University, Lanzhou, Gansu 730030, China

4. School of Economics, Lanzhou University of Finance and Economics, Lanzhou, Gansu 730080, China

Yunnan and Guizhou are two provinces in Southwest China where in recent years drought disasters have occurred due to natural and human factors. This paper reviewed literature and summarized the related achievements of water resources utilization and protection in Yunnan and Guizhou provinces. This included characters and utilization of precipitation, rivers, and karst ground water in the two provinces, and also the various explanations of drought (climate and human factors) and strategies for coping with droughts. Our concluding remarks highlight three lines of future studies: inequalities and equitable use of water distribution, better evaluation systems, and raising awareness through conservation practices.

water resources; water utilization and protection; drought; karst water; China

1　Introduction

Yunnan and Guizhou are located in Southwest China and both provinces contain sufficient water resources. In recent years, however, drought disasters have occurred in these regions due to natural and human factors. Over the past decade, much attention to Chinese geology has come from outside China, while research undertaken by Chinese colleagues have received far less attention. Focusing mostly on Chinese studies, this paper reviewed literature and summarized the related achievements of water resources utilization and protection in Yunnan and Guizhou provinces, in order to provide references for further research on water resources utilization and protection in Southeast Asia and other similar areas. This paper reviewed and examined:

1) characters and utilization of precipitation, rivers, and karst ground water in Yunnan and Guizhou provinces especially vegetation in general, and agriculture varieties in particular, that suffered severely from the 2010 drought;

2) various explanations of drought due to climate and human factors;

3) strategies for coping with droughts, particularly the reasonable utilization of karst water, ecological compensation for forest vegetation water conservation function, studying the vegetation's tolerance to severe drought, and the establishment of a water-saving farming system. Our concluding remarks highlight three lines of future studies: equitable water distribution, better evaluation systems, and raising awareness through conservation practices.

2　Natural and social conditions in Yunnan and Guizhou provinces

2.1Geographical location and topography

Yunnan and Guizhou provinces are adjacent to each other in Southwest China (Figure 1). Yunnan shares a border of 4,060 km with Burma in the west, Laos to the south, and with Vietnam to the southeast. They are connected with Thailand and Cambodia through the Mekong (Lancang) River.

Yunnan is situated in a mountainous area, with high elevations in the northwest and low elevations in the southeast. The average elevation is 2,000 m. Yunnan Province has an area of 394,000 square kilometers, accounting for 4.1% of the nation's total area. Mountain area accounts for about 84%, with plateaus and hills accounting for about 10%, and basins and valleys accounting for about 6% of the province's total area.

Guizhou is also a mountainous province. The western portion is higher, while the eastern and southern portions are relatively lower and flatter. Guizhou Province has an area of 176,167 square kilometers (equivalent to 45% of Yunnan), where mountains account for 61.4%, hills about 31.1%, and basins (Bazi) 7.5% of the province's total area.

Figure 1　Location of Yunnan and Guizhou provinces, their topography and hydrology in Southwest China

2.2Climate and biogeography

Located in a low latitude plateau, with complex topography, Yunnan climate varies much both in "horizontal" and "vertical" (that is in altitude) directions, including low-latitude, monsoon and mountain climates. Annual temperature range remains small on average, though diurnal ranges may vary widely. The region is abundant in rainfall (Figure 2); however, due to the monsoon climate, it has significant annual differences between the rainy and dry seasons. Average annual rainfall ranges from 600 to 2,300 millimeters, and more than half of it occurs between June and August. Yunnan's special climate has both negative and positive features: it is favourable for the growth of crops and the development of tourism, yet its harsh climate is adverse to crops due to the uneven spatial and temporal distribution of rainfall, seasonal flooding, freezing temperatures, and hail.

Guizhou is in a subtropical and monsoon zone of the Eastern Asian continent. It has a subtropical plateau, monsoon and humid climate characterized by less seasonal variation compared to Yunnan, because of its warmer winter, and milder summer. Guizhou has abundant rainfall with an average annual rainfall of 1,108.2 mm. Its uneven distribution in spatial and temporal dimensions results in more rainy days in one year and disparities in its obvious vertical climate difference.

2.3Ethnicity and economy

In 2010, Yunnan had a population of 45.97 million (National Bureau of Statistics of China, 2011). It has the second highest number of minority populations (more than 15.3 million) following the Guangxi Autonomous Region in China, and Guizhou comes in third place.

Guizhou had a population of 34.75 million (in 2010) resulting in 197 persons per square kilometer, lower than Yunnan's total population but much higher in population density than the latter, where there are 117 persons per square kilometer (National Bureau of Statistics of China, 2011). Forty-nine ethnic groups are found in Guizhou, in which there are 10 ethnic nationalities with populations of over ten thousands. Guizhou is a relatively poor and economically undeveloped province compared to the rest of China. Tong and Wang (2006) noted that land resources in Guizhou Province consist mostly of mountains and hills, and fewer basin areas (Bazi). These characteristics impede the use of land for agriculture development, especially in the context of recent population growth, concomitant with a decrease in cultivated land and an increase in non-agricultural land. Tong and Wang (2006) also noted that natural hazards have a major influence on poverty. Natural hazards, especially associated with drought, frost and hail, occur frequently. These factors intensify poverty in Guizhou Province, where population in primary sector accounts for 51.7%, and total population in rural areas accounts for 70.1%. Guizhou possesses a large amount of energy resources, especially hydropower and coal. However, Guizhou's GDP energy and electricity consumption significantly surpasses the national average (Table 1), thus wasting a large portion of its energy resources. In addition, the illiteracy rate is almost twice as high (1.32%) as the national average value (0.71%), although it is well below the average in neighbouring countries such as Burma (8%) or Lao PDR (27%) (Referring to adult literacy, 92% for Burma and 73% for Lao PDR, according to UNDP website (access, February 1, 2013)). These factors impede the development of human resource markets, the introduction of advanced technologies and resource innovation, which may make it more difficult to tackle poverty (Hill, 1993; Tong and Wang, 2006; Han et al., 2012).

Figure 2　The distribution of precipitation over South China (in mm/a)

Table 1　Economic and social indicators in Guizhou Province and China, 2010

3　Water resources in Yunnan and Guizhou

3.1Surface runoff

Atmospheric precipitation is the main water resource in Southwest China and affects the distribution of river runoff. There are six major river systems in Yunnan: Chang Jiang (Yangtze River), Napan Jiang (Pearl River), Red, Lancang Jiang (Mekong River), Nujiang (Salween River), and Irrawaddy, which three chief tributaries in Yunnan Province (Dulong Jiang, Daying Jiang and Ruili Jiang) flow into. The former four rivers flow into the Pacific Ocean, while the latter two flow into the Indian Ocean (Figure 1). Ground water resources are extensive: 108 rivers have a 1,000 square kilometer catchment area, and 908 rivers have more than 100 square kilometers. One finds as well 47 inter-provincial rivers and 37 international rivers. According to a recent approximate evaluation, the percentage of water resources in Yunnan accounts for 7% of the nationwide water resources (not including underground water resources) (Wu, 2004). This means that water resources per capita are 2.4 times higher than the national average. Yunnan, for example, has 400 billion cubic meters of water resources. It is thus a water-rich province according to the total and per capita reserves, but the overall distribution of these resources remains very uneven. On the one hand, its population density remains small, and less land is used in areas where one finds more water, that is in mountainous areas, which accounts for 94 % of the whole area of Yunnan Province; on the other hand, less water is available in lower basins areas, which accounts for 6% of the whole area, which is inhabited by more people (Wu et al., 2003; Wu, 2004). Although there are numerous rivers in Yunnan Province, it is hard to use these water resources because of mountainous terrain.

The rivers in Guizhou Province lie in the upstream confluence zone of Yangtze and Pearl rivers, two major river systems in this part of China. There are 69 counties attached to the Yangtze River Protection Forest Reserve area which is an important ecological barrier upper stream of the Yangtze and Pearl river regions. The river systems in Guizhou are divided into three parts, flowing from western and central Guizhou respectively toward the north, east and south. The Miaoling Mountains in the central part of Guizhou represent the watershed between the Yangtze and Pearl river systems. North of the Miaoling Mountains is the Yangtze River system with a basin area of 115,747 square kilometers which accounts for 65.7% of the total area of Guizhou Province. The major rivers belonging to the Yangtze River system are Wu Jiang, Red, Qingshui Jiang, Hongzhou, Wuyang, Jin Jiang, Songtao, Songkan, Niulan Jiang and Heng Jiang. To the south of the Miaoling Mountains is the Pearl River system with 60,420 square kilometers that accounts for 34.3% of Guizhou's total area. The major rivers, including Nanpan Jiang, Beipan Jiang, Hongshui, Douliu Jiang and Dagou, are all tributaries of the Pearl river system (Figure 1). In Guizhou Province, there are 984 rivers with a length over 10 kilometers. The river runoff in Guizhou Province reached 114.12 billion cubic meters in 2008. These rivers flow through a wide and open valley in the upstream section, and through a narrow valley in the downstream section; which is unusual. Similarly, although there are numerous rivers in Guizhou Province, it is hard to utilize these water resources because of karst geomorphology and mountainous terrain.

3.2Karst groundwater

The Yunnan-Guizhou Plateau is the center of a karst region of Southwest China, which covers Yunnan, Guizhou and three neighbouring provinces (Figure 3). The karst area extends over 780,000 square kilometers (though carbonate rocks cover 1.25 million hectares (Bottazi et al., 2011)) where over 100 million people live. This is the largest and most diversified karst region in the world, and has been added to the "World Heritage" list of UNESCO (Bottazi et al., 2011). The karst holes, voids, caves and hidden underground river water systems are well developed due to humid climate, strong karstification and abundant rainfall. Karst groundwater is formed through ground surface water leakage and leaching in karst areas (Shi et al., 2005; Pan and Lu, 2010).

Karst water can be divided into different types according to the characteristics of karst development and landforms (Yao and Han, 2006; Wang et al., 2007; Pei et al., 2008). The bare karst water system widely distributed in the Yunnan-Guizhou Plateau is the most common type. This system is basically distributed above the base level of erosion and discharged through the forms of springs and underground rivers. It can be divided into two subclasses: surface and shallow. (1) Surface karst water systems form through local and discrete surface springs. Most of these are seasonal springs that appear in large numbers in mountainous areas and are characterized by their small catchment area, their exploitability (e.g., agriculture) and their use by local residents to provide drinking water. (2) Shallow karst water systems are underground river systems that are mainly composed of karst caves, holes and pipes. They are located at depths of 50–300 meters in mountainous areas. A shallow karst water system has a large catchment area and large runoff. Most of these systems are discharged in the valley and are the main water resource for industrial production and local communities living inthe karst areas of Southwest China. A shallow karst water system is locatable above the 10- to 30-meter-thick karst aquifer, and an important source of water supply for the local residents living in town areas due to access to better water quality and greater volume. A deeply buried karst water system is often located under the rock layer with a thickness of 100–500 meters. If the burial thickness is greater than 500 meters, it is not suitable for exploitation (Yao and Han, 2006).

Figure 3　The distribution of karst areas in South China

3.3Characteristics of karst water resources in Yunnan and Guizhou

Yunnan and Guizhou provinces have rich and various water resources with an average annual rainfall of more than 1,100 millimeters. Unfortunately, water resource distribution is uneven in spatial and temporal dimensions, leading to problems of exploitation and over-utilization. Water resources in this area vary according to three main features. First, severe natural conditions, such as the large elevation difference, deep gorges, well developed karst systems, thin soil layer, and sparse vegetation, result in the lack of ground surface water in mountainous areas and the difficulty of development and utilization of water resources. Second, precipitation mainly occurs from May to September, accounting for 60%–70% of the yearly average. This situation often results in summer floods and spring/winter droughts. Third, in some areas, land and residential areas are scattered and conditions are not suitable for the building of large water conservancy facilities, thus resulting in water shortages in these areas (Lu and Zhang, 2006; Shan and Deng, 2006).

3.4Water resource utilization

Karst water is the main source of water supply in the karst region, and at times the only water source during the dry season, especially in Yunnan and Guizhou. Water resources available for utilization in Yunnan and Guizhou amount to an annual average of 9.95 billion cubic meters and 8.88 billion cubic meters, respectively. However, the potential amount of groundwater to be exploited and utilized remains low because of what is considered by Chinese researchers as poor geographical and economic conditions (Kong et al., 2008; Ma, 2010; Pan and Lu, 2010). Problems with regards to water resource utilization in karst basins have been identified. Due to widespread karst areas (Figure 3), precipitation quickly turns into lower groundwater, where it is harder to exploit. Thus, although there is abundant precipitation during the rainy season, some rural areas still lack water for irrigation and self-consumption due to these natural conditions and the lack of or difficulties with implementing an effective water conservancy project.

Second, water pollution is serious, difficult to prevent, and challenging to remedy. Karst basin water resources are easily contaminated because the karst water system consists of ground surface and underground waters. If the ground surface water is contaminated, it flows quickly into the underground water system almost with the same original concentration of pollutants. Less oxygen, no sunlight, and fewer mi-croorganisms in the karst groundwater system make it more difficult to purify or dispose of contaminated water. Third, karst water resources are poorly regulated or monitored with flood and drought disasters often occurring. Large- and medium-sized water storage projects are generally built in the mountains but they have small capacities to control the drainage and storage of water resources. Moreover, these projects are difficult to construct because of widespread karst holes, voids, and caves in the karst basin (Lu and Zhang, 2006; Shan and Deng, 2006; Kong et al., 2008).

4　Drought disasters

Since 2009, more attention has been paid to issues related to water resources in China due to three serious drought disasters that occurred in the country. The January 2009 drought mostly affected central China, just south of Beijing with Hebei and Shanxi provinces at the center; the August 2009 drought, less severe, affected the northeastern provinces; while the March 2010 drought lasted longer (six months) and was centered on the Yunnan–Guizhou provinces. This latter drought is thought to have a return period of about 50 to 100 years (Tao et al., 2012). The drought caused huge economic losses to the area and had adverse impacts on the production and life quality of the local residents.

4.1Drought and its impacts

In the southwest of China, whenever a serious drought disaster occurs, it always causes a significant diminution in the availability of drinking water for the local residents and a reduction in agricultural production. According to the report published by the Ministry of Civil Affairs (Qiu, 2010), the 2010 disaster affected 8.1 million people, that is 18% of Yunnan's population, who lacked drinking water, and the province suffered a 2.5 US billion dollar loss in crops. The total affected population reach 61 million people (Tao et al., 2012). According to Cheng and Tao (2010), drought disaster always represents the biggest risk to China's agricultural production, and it seriously affects the supply of agricultural products as well as food security.

At the same time, the drought had serious consequences on the ecological system. From August of 2009 through March of 2010, the area of vegetation that suffered from this disaster in Yunnan, Guangxi, and Guizhou accounted for more than 80% of the total area in these three administrative regions. Farmland vegetation was seriously damaged resulting in death and failure of the crops and dryness of the reservoirs and ponds (Wang et al., 2010). Tao et al. (2012) put at 6.73 million hectares the area of crops affected at the worst period, with total economic loss at 23.66 million Yuan (1 USD = 6.8 CNY). Impacts on natural vegetation were visible and vegetation growth apparently became slower and some plants died. Large areas of vegetation in dry and hot valleys and karst areas degenerated. The drought also affected local biodiversity (Wang et al., 2010).

4.2Causes of drought

Climate itself is seen as the first cause behind the 2010 drought. Precipitation was uneven in temporal and spatial scales in 2010 (Table 2). Some reports suggest that the 2010 drought in Yunnan might have been caused by the El Ni?o/Southern Oscillation (ENSO), an atmospheric circulation system that originates in the eastern Pacific Ocean and brings rainfall to Southeast Asia. During El Ni?o years, winds from the Pacific weaken, leading to droughts in the region. Spatiotemporal changes in annual precipitation, evaporation, and runoff for almost half a century in the period from 1956 to 2000 in Guizhou were also key factors. The spatial patterns revealed by precipitation and evaporation maps closely associated with stream flows suggested the impact of climate changes, bringing warmer and drier conditions during this period for almost a half-century. These were the prime driving forces dominating the changes to hydrological processes in Guizhou (Peng et al., 2009; Yang et al., 2009; Ma, 2010; Qiu, 2010).

From September 1, 2009 to February 23, 2010 rainfall in Yunnan attained only 163 mm, the lowest mark since 1952 (Tao et al., 2012).

The second cause highlighted by Chinese researchers is the karst situation of the region. As we have seen, although total precipitation is considerable, surface water seepage occurs widely due to the well-developed joints and cracks in limestone and the connected underground caves and rivers. These features result in surface water storage systems that have a low capacity and efficiency in storing and regulating water resources (Guo and Jiang, 2010; Mu et al., 2010). At the same time, the availability of resources does not match the location where they are needed: ground surface water is mainly distributed in the deep valley while agriculture lands are mostly located on the Plateau where local residents also live. When there is a lack of precipitation during the dry season and a shortage of surface water, karst groundwater remains the only water source for residents in mountainous area (Shi et al., 2005; Pan and Lu, 2010).

Third, human factors have also been identified as causes of the 2010 drought. Intensive human activity, such as over deforestation, massive mining, and unreasonable land use (no definition provided), causedserious damage to the ecological environment. These causes lead to vegetation reduction, enhanced surface runoff, and serious soil erosion (Shi et al., 2005; Pan and Lu, 2010).

Table 2　Monthly rainfall in Yunnan in 2009, 2010 and average over 30 years (Unit: mm)

1) Deforestation. For the pursuit of high economic benefit, large areas of secondary forests were cut down and eucalyptus, rubber, and tea trees were widely planted in Yunnan and Guizhou. Although this deepened the connection of this area with the world market, it also simplified community structure and functions; vegetation was more sparse, and hydrological, conservation of water, and fertilizer functions weakened (Ma, 2010; Mu et al., 2010). Natural forests are a key regulator of climate and hydrological processes. The thick layer of organic material in forests absorbs up to seven times more than its weight in water. They also have an extensive network of roots that keep the ground moist, and their canopy can trap water from evaporating, creating a dense fog that keeps the myriad plant species alive during dry seasons (Qiu, 2010).

2) Mining. There are rich coal, non-ferrous, and precious metals mineral resources in Yunnan and Guizhou. In 2002, the number of large ore enterprises reached more than 300. While the mines were in production, they occupied arable lands, vegetation was destroyed, and waste soil and slag were produced (Wei, 2002). This caused extensive disturbance and destruction to surface areas. In addition, massive mining seriously destroyed the hydro-geological structure of the karst region, causing ground surface subsidence, mountain cracks and even changes in water flow direction. Moreover, local and regional water cycle and balance were also damaged (Wei, 2002). Water pollution caused by careless mineral mining and land exploitation makes drought disasters worse. Valuable water resources have thus been polluted and become waste or non-usable water (Huang, 2002; Jiang et al., 2006; Zou et al., 2006; Kong et al., 2008; Zhang et al., 2011).

3) Weakness in water conservancy projects. Water infrastructures in Southwest China were not sufficient to cope with the 2010 drought: their numbers are too small and deterioration problems occurred, which made the drought disaster even worse. Most of the water conservation facilities were built in the 1950s–1960s in Yunnan and other provinces of Southwest China. Because of their age, some of the infrastructures failed to work. Additionally, the large- and medium-sized water storage facilities were too limited in construction. For example, in 2009, there were only 36 medium-size reservoirs in Guizhou Province. The rest of the 1,935 reservoirs were of smaller size. This put the total storage capacity to less than 2 billion cubic meters. The weak investment in building water conservation facilities contributes to the low efficiency when utilizing water resources. The percentage of water utilization is only 6% of the total water resources in Yunnan, although it has the third highest volume of water resources among the provinces and autonomous regions in China, even lower than the national average, which stands at 10%. As a consequence, farmland irrigated areas account for only 35% of the total area of cultivated land in Yunnan Province, agriculture water far below the national average of 8%. Due to lack of water, two-thirds of farmland is showing low yield conditions. In 2010, the water resources annual gap between supply and demand attained 4,200 million cubic meters. With economic development likely to occur within the next few years, it is also likely that the gap between supply and demand will continue to expand (Mu et al., 2010; Sun, 2010; Gong et al., 2011).

5　Countermeasures against drought

5.1Development and utilization of karst groundwater

Karst groundwater is characterized by a faster water flow, larger burial depth, larger seasonal variations, and a more complex distribution. For these reasons, solutions adopted to solve the drought problem in karst areas need to vary according to specific geological, geographical, and economic conditions.

Possible solutions to overcome these (or some of these) problems have been identified and listed by Pan and Lu (2010). For example, small water storage and conservation projects, such as some stream- or rainwater-collecting projects and small and individual wells can be constructed in the karst areas where there are poor geological conditions, such as less water resources, or a large burial depth. As for the larger- or medium-sized water storage and conservation projects, such as underground reservoir or well groups, Pan and Lu (2010) suggested that they should be built to provide high-quality drinking water and develop cash crops to raise income levels for local residents – although these approaches do not address the deforestation issue.

For an integrated underground river system, Pan and Lu (2010) have found different development and utilization modes; they present them according to their position in the watershed. In the upper streams, some karst springs appear, and small water storage and conservation projects can be adopted. If water is buried deeply, that is more than 50 meters, a small single well can be drilled to exploit and use the underground water. In the middle stream, the visible and hidden karst rivers occur alternately; farmlands are located mostly in lowlands; the underground water is shallowly buried. It is here that construction of some medium-sized and large storage and conservation projects to use the underground water would be most useful. For instance, the large deep well or well group can be drilled, and some underground reservoirs can be built to exploit and utilize the abundant underground water resources. In the meantime, some small projects are also suitable and can be combined with those large ones. In the lower stream, the river valley is very deep; the population is distributed more sparsely; the underground water is buried deep, between 100 to 300 meters. It is hard to develop and utilize underground water. Some deep wells are not suitable because of the higher cost and risks. So, according to Pan and Lu (2010), small storage projects such as water tanks and water pools can be built to use the ground surface karst water. In the outlet section of the hidden underground rivers, cascade dams and hydropower stations can be built. During the exploitation and development of water resources, concerns should have been paid to land subsidence and underground water contamination in karst areas (Pan and Lu, 2010).

5.2Ecological compensation

In order to control soil erosion and restore environments, the Chinese government has initiated serious ecological rehabilitation projects such as the Returning Farmland to Forests Program or Returning Farmland to Grassland Program (RFFP or RFGP) and Natural Forest Protection Program (NFPP). These projects brought about marked influences on land use change and soil erosion in Guizhou Province (Xu et al., 2011). These projects developed from the principle that vegetation can conserve water by helping to reduce surface water runoff. Some researchers think that the RFFP or RFGP could be speeded up, especially in areas where one finds steep slopes of more than 25°. Through these programs and according to Chinese researchers, in areas where they have been implemented, the ground surface has been successively protected and soil or sand can no longer fill the karst caves or holes. Consequently, more karst spring water is available in drought seasons. This spring water is the common water source for local residents in the event of droughts (Li and Wang, 2001; Guo and Jiang, 2010). Of course, these projects need to be assessed on the long term; water availability is not just occurring year-by-year.

Currently, compensation policy under these programs has, to some extent, improved ecological environments in the region, but problems still need to be resolved. In order to improve the worsening ecological environment, some have suggested that it would be necessary to levy an ecological tax and fulfill the ecological transfer payment. Some argue that the innovative suggestions of ecological compensation should be adopted in these areas (Chen, 2005).

5.3Adaptability of vegetation to drought

Drought stress is one of the most important factors limiting the survival and growth of vegetation in the harsh karst areas of Southwest China. Detailed knowledge about the ecophysiological responses of native plants with different growth forms to drought stress could contribute to the success of re-vegetation programs. Studies of different wild plants to drought stress adaptability provide references for the restoration of ecological vegetation in karst areas (Chen et al., 2009; Liu et al., 2011, 2012). At the same time, it has been suggested that drought-resistant crop varieties should be chosen and cultivated. The choice of crop varieties not only should produce high yields, high quality products, and be efficient, but also needsto adapt to bigger climate variations, including drought periods (Cheng and Tao, 2010). Finally, it has also been suggested that some water-saving regulations and rules should be established for farmers to plant crops. The goals of these rules are to reduce rainfall runoff and evaporation, and to increase the rate and efficiency of irrigation water in the southwest of China (Chen et al., 2005; Zhu et al., 2006).

Finally, it can be highlighted that most of the suggestions or solutions presented here (water, compensation, adaptability) concord with those presented more recently by the team of Tao et al. (2012). They have studied three episodes of drought disasters in 2009 and 2010 and their conclusion was that government policies "should emphasize entry-prevention measures that reduce adverse impacts early in a drought episode rather than focus solely on improving performance in achieving a rapid exit transition from drought" (Tao et al., 2012; Wang et al., 2012).

6　Summary

There are both sufficient water resources and drought challenges in Yunnan and Guizhou provinces of China. This article summarized the characters and utilization of precipitation, rivers, and karst ground water in these two provinces and the agriculture and vegetation situation affected by severe drought in these areas. The reasons for drought range from climate and topographical factors to various human factors. Three main strategies have been applied to and identified for coping with droughts in this specific area: reasonable use of karst water, ecological compensation for forest vegetation water conservation functions, studying of the vegetation's tolerance to severe drought, and establishing water-saving regulations and rules. We think these practices are not enough. This literature review on water issues in southwestern provinces of China brought us to identify, in order to improve the situation of water environment and management in Yunnan and Guizhou provinces, three lines of work: (1) more equitable water distribution; (2) better evaluation systems; and (3) raising awareness about water disparities within these provinces.

6.1Justice of water distribution between urban and rural areas

The priority given to water utilization by cities leads to uneven distribution of water resources between urban and rural areas. During the past decades, water conservation facilities were built mostly for cities and neglected in rural areas. Moreover, water resources were diverted from rural areas to cities through various kinds of infrastructures. When these vast works were built throughout the countryside, no drainage facility was set for rural areas. Even when severe droughts occurred, farmers who were living close to the water conservation facilities were "thirsty" because they did not have access to the nearest water. Therefore, a fair distribution of water should be considered between urban and rural areas when the original or new water facilities are reformed or constructed.

6.2Innovation of government evaluation system

There are many sources of rivers in Yunnan, Guizhou, and other provinces with fragile ecological environments. In order to protect the ecological environment of these areas, new governmental evaluation systems should be organized, systems different from other provinces with good ecological environments, and thus more adapted to local ecological conditions. Even with equal government measures, results in terms of how people are able to improve their socioeconomic conditions remain diverse, often because of water availability and poor agricultural yields (Chen and Maire, 2011). Raising the Gross Domestic Product should not be pursued in Yunnan and Guizhou provinces, not without giving priority to the ecological environment, especially water resources. It is a point of view shared by other researchers: ecological environments, people's livelihoods and happiness should be prioritized in Yunnan, Guizhou, and other provinces with a fragile ecological environment (Shi, 2010).

6.3Raising disaster awareness

Compared with a stronger disaster awareness in Northwest China because of perennial drought, it is taken for granted in China that there is a weaker disaster awareness in Yunnan and Guizhou provinces, although this fact has not been measured precisely (A recent research by Rambo and his colleagues (2003) addresses this gap in the literature by studying environmental consciousness in Hong Kong, Japan, Thailand, and Vietnam. To our knowledge, nothing of this approach has been undertaken for Southwest China). This lack of awareness has further exacerbated the effects of drought. Methods of rainwater collection through cellars should be learned in Yunnan and Guizhou. At the same time, experiences in rainwater collection and conservation awareness elsewhere in the world, such as in Antigua or Singapore can also be shared.

In summary, we think there is a lesson that should be learned from the 2010 drought in Yunnan and Guizhou provinces. But it also has to be considered within the overall situation, which includes, accordingto Chen and Maire (2011), addressing demographic issues, the quality of education, modern road infrastructures, and finding new resources. Options like developing organic agriculture, without pesticides, already widespread in Guizhou, could also be examined (Chen and Maire, 2011). Such extreme weather events, are likely to occur more frequently according to the Chinese Academy of Sciences (Qiu, 2010): people of these provinces would be better prepared to deal with droughts. All in all, drought disasters in Southwest China are caused by not only natural factors, but also the combination of natural and social factors, which shows that water resources has been weakly protected and used with low efficiency. The proposed measures need further fulfillment.

Acknowledgments:

This research was funded by the National Social Science Foundation of China (No. 10CGL050). Authors also kindly thank editors and Steve Déry from Laval University, Canada, for his support and careful revision about this study.

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*Correspondence to: CuiFang Wu, School of Agriculture & Forestry Economics and Management, Lanzhou University of Finance and Economics, Lanzhou, Gansu 730080, China. E-mail: wucf@lzcc.edu.cn

March 16, 2015 Accepted: May 14, 2015