Research, demonstration, extension of rainwater harvesting in the loess plateau of Gansu China

Transcription

1 Research, demonstration, extension of rainwater harvesting in the loess plateau of Gansu China Li Yuanhong and Zhu Qiang Gansu Research Institute Water Conservancy 1

2 Water resources in China Precipitation on the continental: 619 Billion m 3. ARWAR(Annual Renewable Water Resources) = river runoff + non-repeated groundwater: 280 billion m 3. Sixth largest in the world. ARWAR per capita: m 3 /head a, ¼ of the world level. In southwest China, ARWARPC is more than m 3 while in some of the north and northwest China, it is as low as m 3 /head. River runoff from June to Sept is 60-70% of yearly total, only 19-24% in May to June when crops need most water 2

3 Water challenge to China About 29 million of people have no access to drinking water; Impoverished population are about 30 million, most of them are lacking of water; Water shortage caused annual loss of 25 billion USD of industry production and 25 million tons of grain; Four hundred cities out of 668 are lacking of water. Among the 400, 108 cities are suffering from serious water shortage that amounts to 108 million m 3, groundwater overexploited 10.8 billion m 3. Low agriculture productivity causes food insecurity in many areas. 3

4 Critical areas of water shortage in China Semi-arid loess plateau in Gansu, Ningxia, Shaanxi,, Qinghai and Inner Mongolia of the northwest China; Semi-arid mountainous areas in Shanxi and Hebei of the north China; Karst regions in Guizhou, Guangxi, Yunnan provinces of the southwest China; The dry hilly areas in Sichuan, Henan provinces of middle China, and The islands and rocky coastal areas. 4

5 Common features of these critical areas Serious water shortage, water insecurity Impoverished life of local inhabitants Frequent drought causes low agriculture level and food insecurity Serious soil erosion, degraded lands and deteriorated environment Vicious circle among water scarcity, agriculture production and environment deterioration 5

6 Critical areas for water shortage in China 6

7 Water scarcity in Loess Plateau of Gansu Annual precipitation 330 mm. Low runoff coefficient: Difficult topographic condition for water conveyance system: widely distributed loess plateau and hills crisscrossed by numerous gullies and ravines. Unevenly distributed rainfall. Groundwater is very little and with bad quality. AIRWAR per capita is only 230 m 3, 1/40 and 1/10 of that in the world and in China. 7

8 Water scarcity in the Loess Plateau of Gansu Province Drought occurs frequently: history archive: 634 droughts in 1400 years since Sui Dynasty; statistics: 36 droughts in past 40 years. Low crop yield: in the dry year. Monotype agriculture structure: without water condition, most cash crops cannot be grown, 90% of land is planted with grain crops. The annual income per capita is as low as 100~150 USD. 8

9 Serious water shortage: 29 million people without access to safe water supply. Karst cave, high mountain and deep valley, very difficult to make use of the river water, uneven distributed rainfall Gansu loess areas Guangxi Karst area, SW China Water resources per capita only 230 m 3, annual precipitation 300 to 500 mm, surface and subsurface water is very scare 9

10 Aridity causes serious soil erosion Erosion modulus is as high as 5000~10000 t/km 2 annually, which means that the surface soil will be eroded with a layer of 0.5~1 cm thick averaged in each year. Deterioration of vegetation was speeding up because of continuous uprooting all straw and grasses for fuel use. Farmers reclaimed as much lands as possible on the slope land regardless of the low yield. Environment of the whole areas was deteriorating in an accelerated speed. 10

11 Land degradation: even land on the steep slope were cultivated to ensure food supply. Vicious circle: the poor they were, the more they reclaimed, the more they reclaim, the poorer they would be. Water scarcity caused very low forest coverage. Serious soil erosion in loess plateau of Gansu. Erosion modulus is 5000 to t/km 2. 11

12 How to address water scarcity problem? In Gansu the technical people and the local farmers have made many efforts in the past 40 years to improve the people s s living condition and the agriculture production within the traditional dry farming practices: relying on the natural rain. Under the inverse condition in the loess plateau of Gansu to enhance the dry farming to a new stage, it is found necessary to artificially supply water to the crop. 12

13 How to get water? Conventional solution is to divert water from out of the area. But the natural conditions cause many shortcomings: High input and O&M cost; Long time to be brought to play; Centralized solution, poor people in the mountainous area can hardly get access to it. Many environment problems associate. The most potential and easy-to-use water resources in the area are rainwater. 13

14 Innovation Rainwater harvesting is a sustainable approach for integrated development of rain-fed agriculture. In critical areas, it is even an irreplaceable measure for human survival and development. 14

15 Research, Demonstration and Extension Project on RWH An experiment research, demonstration and extension project had been implemented by the Gansu Research Institute for Water conservancy (GRIWAC) since The project was aiming at to study the rainfall-runoff runoff relationship under different rainfall condition and on different rainwater collection field, to find out the appropriate rainwater utilization pattern and to formulate the design procedure for the RWH system. 15

16 Research, Demonstration and Extension Project on RWH 28 testing plots with 8 different materials including concrete, tiles, plastic film, cement soil, lime soil, compacted soil and the natural soil were set up. During 1988 to 1990, 421 rain-runoff tests were conducted. relationship between RCE and rainfall amount and intensity were worked out. Yearly RCE for areas with annual precipitation of 300, 400 and 500 mm for 8 kinds of materials were calculated using the data of representative gauges. 16

17 Research, Demonstration and Extension Project on RWH Rainwater utilization pattern was set up on the basis of traditional practices.. The catchment for domestic use is the improved roof and hardened courtyard. Shuijiao (water cellar) and Shuiyao (water cave) are used for storage. Guideline for design and construction of the RWH system was worked out and was later developed into a local technical standard and basis of the National Code of Practice issued by the State Ministry of Water Resources in

18 Research, Demo and Extension Project By the end of 1994, 2.4 million m 2 of collection field and 22,280 water cellars were built. RCE reached 67-70% 70% Farmers who owned a RWH system had enough water to meet their basic need. Twenty-two two irrigation pilot projects were established with total irrigated area of 1.4 ha. In Yuzhong County, 16 green houses were set up 18

19 Project In 1995, a serious drought occurred in Northwest China. 3 million people and 2 million animals could not get water supply. Most of the summer crop in the rainfed areas died out. Gansu Provincial Government made a decision to carry out Rainwater Catchment Project. The government decided to support family in the area where no surface water nor groundwater exists in the area to build one rainwater collection field with area of m 2, two underground water tanks each with capacity of m 3 and one piece of land close to the household to be irrigated by stored rain. 19

20 Raising fund for the Project In the "1-2-1" 1" project, 190 million CN Yuan (13.4 million USD) for subsidies to farmers were raised. The government raised 53 million CNY. For the other part, a donation movement was mobilized by the government and the media. Total amounts of million CNY (6.9 million USD) were gathered from the whole society. 20

21 Result of Project Beneficiaries of the project amounted to 1.31 million populations in 264,000 families of 2018 villages under the jurisdiction of 27 counties. Total area of catchment amounts to million m 2. There were 286,000 newly designed water cellars being built. Irrigation water was applied to about 1.33 thousand ha of land for developing courtyard economy. 21

22 Larger scale RWH project for domestic water use in other parts of China Sichuan Province Thirst project in SW Sichuan, Guizhou and Guangxi province; RWH project for domestic use in the islands and coastal area in Shandong and Zhejiang province Guangxi Province 22

23 RWH project for agriculture production Encouraged by the successful Project, the government initialed the RWH Irrigation Project in While project offered water for people s s basic need to ensure human existence, RWH irrigation project opens up the way to develop the economy and improve farmers life in the dry mountainous area. 23

24 RWH Irrigation project To lower the cost, people make fully use of the less permeable surface of existing structures like paved highway, country road, threshing yard and the natural slope as catchment. The type of storage tank is the same with that in the system for domestic water supply but with larger volume from m 3. Highway catchment Rainwater tank and the fields 24

25 Result of RWH irrigation By the end of 2004, there were 2.2 million newly built storage tanks. 339,000 ha of land got supplemental irrigation. Yield increased by 40%. The project is still developing with a speed of enlarging ha of irrigated land each year. 25

26 Highly profitable agriculture development with RWH With water in the tank, farmers started to change their agriculture structure: About greenhouses developed rapidly in the mountainous areas after implementation of RWH projects. 26

27 Benefit of greenhouse: The simplified greenhouse with area of 350 m 2 and built with bamboo and steel rod and covered with plastic films costs about US $1000, while the annual net profit can be up to US$ 350~500. At this rate, the investment can be returned within 2-3 years. 27

28 Dingxi Highly Efficient Agriculture Garden The Garden has area of 3 ha on a formerly wasted hilltop where hundreds of greenhouses have been built Main products are devirus potato seeds, mushroom, vegetables, flowers. Animals like pigeon, chickens, rare dogs, etc are raised 28

29 Farmers sayings: Water equals to grain, water equals to money To be rich, build water cellar in your field 29

30 Significance of rainwater harvesting in China Effective way for domestic water supply A breakthrough of the rainfed agriculture Promotion of the ecological and environmental conservation 30

31 Effective way for domestic supply The local farmers get a reliable, clean and cheap water source to meet their basic need. Water supply condition was dramatically changed. Each family can thus save 70 labor days each year in average for carrying water before the project. The surrounding of the farmers houses is greatly improved. A better environment raised the living quality and stimulated the spiritual outlook. 31

32 Quality problem of rainwater for domestic use Farmers are advised to boil water before drink. To find an alternative way for getting fuel and to avoid uprooting the vegetation, a simple solar heater is developed in the area. It can boil water in a 5-5 pound container within 30 minutes under sunshine. The cost is only 15 USD. There are 5 workshops for producing solar heater in the area each with yearly production capability of sets. 32

33 Breakthrough of rainfed agriculture According to investigation of some regions, with RWH, yield can be raised by 20-88%, averaged about 40%. The role of RWH for agriculture is not only in raising the yield but also in creating condition for agriculture structural modification and income generation. 33

34 Traditional adaptation measures for enhancing agriculture production Reforming the land, e.g. terracing, contour planting; Deep plough, harrow, tillage, mulching, etc to keep soil moisture; Fertilizing to increase resistance of crop to water stress; To breed new varieties that can have higher resistance to water stress and adaptability to the rainfall condition; Mini-catchment, floodwater harvesting and spate irrigation 34

35 Traditional dry farming ---valid but limited effect In the normal year, these measures can enhance the crop yield but are not so effective in the dry year; The reasons is: The inadequate adaptation capability of rainfed agriculture measure to the climate variability; 35

36 The inadequacy of adaptation capacity of traditional dry farming practices Principle of water management for dry 200 farming is to store as 150 much rainwater into 100 the soil as possible 50 and to make best use 0 of soil water. This was proved to be effective in mitigating the drought but the effects were limited. Water depth (mm) Rainfall Month Crop demand The inadequacy of adaptation capability of the traditional rainfed agriculture to the climate variability is mainly due to not being able to bridge the gap between time that crop needs water and the time that rain occurs. Usually the gap would extend to 6~8 months. 36

37 Conclusion got from experiences in past decades: Only to combine artificial water supply with the traditional dry farming measures would enable a stable and high level of crop yield in the rainfed agriculture. Formula of Updated dry farming = Rainwater harvesting + traditional dry farming measures 37

38 Changing agriculture structure: Greenhouses; Develop orchards; Grow cash crops; Animal and poultry raising 38

39 Promote eco-environment environment conservation Enhancement of production after RWH project enables farmers to shift growing grain crops to planting trees and grasses. On the other hand, when the agriculture structure was changed, development of animal husbandry asked for more grass land. All these had positive effects on building vegetation thus improving the environment and ecological condition. 39

40 Land conversion program A programme issued by the State Government in the Strategy of Great Development of West China. It encourages farmers with favorable policy to shift their lands on the slope steeper than 25 0 to tree and grass planting to stop soil erosion and to reconstruct ecosystem. 40

41 RWH rapidly spreading to the whole country from 1990 s To the end of year 2001, there have been 12 million of mini-size tank being built with storage capacity of 16 billion m 3. Tank group in Guizhou Province for paddy irrigation Typical rainwater tank in SW China About 36 million of rural populations get water supply for domestic use from the RWH systems. 2.6 million hectares of crop field get supplemental irrigation. 41

42 Promotion of RWH internationally Since late 1980 s, many politicians and experts from abroad visited the RWH projects in Gansu and China Closing ceremony 2005 International Training courses on Rainwater Harvesting and Utilization have been conducted in Lanzhou by GRIWAC under support of China MOFCOM from

43 International Training Course on rainwater Harvesting and Utilization Participants visited solar heater workshop in 2004 In the lecturer room,

44 International cooperation Lecturing for experts of the Ministry of Water Resources and Electricity, Saudi Arabia Kingdom Assist Gigawa State of Nigeria to build water cellar Study potential of RWH in Saudi Arabia 44

45 Problems and challenges of RWH in China Firstly, the quantity and quality of the domestic water supply is not enough as China has put forward the goal to build the well-off society all over the country. In many areas, biological quality of the water is a problem for drink. Secondly, although demonstration has shown benefit of low- rate irrigation to enhancing production and improving agriculture structure but more promotion work for the awareness and capacity building is necessary, which is neglected by the government. To help farmers understand how to make use of rainwater in most efficient way is a big challenge and a long term job to the authority and the technical persons. 45

46 Problems and challenges of RWH in China Some technical problems have to be solved, like to develop the cheap and efficient catchment material, to reduce the cost for the storage tank, etc. How to irrigate different crops with small amount of water to gain the maximum profit is also an important issue. The Chinese experts have carried out many experiments on it and some useful results have been obtained but they are still not enough 46

47 Conclusion RWH should not be regarded only as a temporary measure against drought but be taken as an integrated strategy for alleviating poverty, developing the agriculture production, controlling soil and water loss and improving the ecological and environmental system. In China, the area where RWH project has been rapidly developed refers to 13 provinces (regions, municipality), 700 counties with area of about 2 million km2. In these areas, the population amount to 260 million. 47

48 Rainwater harvesting becomes strategic measure for integrated rural development in the dry mountainous area Decentralized; Use indigenous resources; Adopt appropriate and acceptable technology; Low input and O&M fees; Household/community ownership of RWH project enables wide participation; It is a long-term strategy for sustainable development for the water shortage area. 48

49 Message from the Gansu s practices in the past 20 years: Rainwater should be taken as the equal component with the surface and subsurface water in the integrated water resources management; Rainwater harvesting is effective in poverty alleviation. Mainstreaming rainwater harvesting is necessary and urgent to meet the Millennium Goal 49

50 Thank you! 50