Farmers in northwest China's Gansu province have benefited from rainwater harvesting as the collection method has been improved and supported by the government. This method has also stimulated many other places in China as well as in the world to collect rainwater. Senior advisor and professor of Gansu Research Institute for Water Conservancy Zhu Qiang told us the story during the World Water Week which was held in Stockholm this month and the project was exhibited there.
Zhu Qiang said with an annual rainfall of 300-400 mm, farmers in Gansu have to collect rainwater for drinking for nearly a thousand years. But traditional harvesting rate was only 10%. And the collected water was also very dirty.
In 1980, Gansu Research Institute for Water Conservancy conducted a pilot project of advancing the method of harvesting rainwater. Professor Zhu Qiang was involved in the project management.
"Our experiment was to improve the collecting surface so that the leaking became less, the water became cleaner and the collection surface expanded. Our targets were mainly farmers who lived in remote mountainous rural areas where there is a lack of water. We began our experiments in a few families as a demonstration." explained Zhu Qiang.
He said the traditional way of rain collection relied on the small roof which had a lot of leaking due to the clay roof. They changed the clay roof into cement tiles and clay courtyard into concrete courtyard. And the collection surface increased from 50 square meters to 100 square meters per family. Thus, the rain harvesting rate reached nearly 80% which was enough for household use.
Meanwhile, they encouraged the farmers to dig up more water cellars in order to collect water from the slopes and roads for growing vegetables in their courtyards.
Zhu Qiang said they first built 16 plastic green houses for the locals to grow vegetables. The local people never grew green vegetables such as egg-plants or green peppers before. But this rainwater harvesting made the farmers not only eat the vegetables themselves, but also sell some. The experiment was quickly spread up and from 1988 to 1994, the number of people who did this increased to 200 thousand.
In 1995, there was a historic draught in the area. The farmers didn't have any harvest in agriculture, but the stored rainwater in the cellars kept them alive with the household use of water.
This practice was soon promoted in the whole province. With the support of the provincial government, a plan of solving one million people's drinking water problem was made. The project 121 was to help every family to build one rainwater collection surface(80-100 square meters), two underground water cellars(15-20 cubic meters) and one piece of land to be irrigated for growing cash crops.
Within one year, the project was completed with a success. About 1.2 million people solved their drinking water problem.
Zhu Qiang said the reason for the success was that due to the experiment, the practice was easy for farmers to accept. The main problem was lack of fund. With the support of the provincial government, every household could get 400 yuan which enabled them to buy 1.5 tons cement at that time while the project management gave technical guidance and training. The labor came from farmers themselves. They were happy to have the ownership of the cellars. They could exchange their labor with other villagers in getting raw materials such as sand nearby. Those who had the tractors could help those who had not and the latter could help the former in other forms of labor. This way they saved a lot of cost in building the facilities.
The project was well accepted and expanded to many more people. At the end of 1996, the government also proposed to provide supplemental rainwater to agricultural irrigation. Although it was a bit too ambitious and difficult, in cooperation with Gansu Agricultural University, they implemented the method among half a million people.
In 2005, the Water Conservancy Research Institute conducted an appraisal about the project. The conclusion was that it was very cost-effective in helping 1.3 million people have drinking water and irrigating 260 thousand hectares of agricultural fields, accounting 20% of the local land.
There are about 300 thousand vegetable growing green houses in the area now. With the annual income of 5000 yuan or about 700 US dollars, farmers are willing to grow vegetables in this way. Compared with growing grains, the income of growing vegetables can be 10 times more.
When China implemented the policy of developing the western regions in 2000 and called for returning land into forests and grassland, the rainwater could be used to water newly planted trees ensuring a higher survival rate.
Zhu Qiang said about the water quality, they let the local people boil the water before they drink it. But to boil the water needs more energy, where can they get energy?
Then they invented a kind of solar heater which simply uses a mirror to absorb the solar heat. With a proper angle, the heat is enough to boil the water within half an hour. And the cost is far lower than the normal solar cells. The government supported the 15 dollars cost.
"The water must be boiled because there was still some bacteria in the water which made the water not up to the drinking standard while it reached standards in other chemical test. " said Zhu Qiang.
In 2003, the project won the first prize in World Water Action campaign during the World Water Forum which was held in Japan.
The project was also supported by the United Nations Environment Programme.
Ministry of Commerce also supported them to conduct some training for developing countries. Thus since 2003, they have trained 165 delegates from all over the world during 3 years. Now the training continues. The practice has been applied in some counties in Nigeria. So far about 200 water cellars have been built in rural Nigeria.
Meanwhile, China is also going to train people in Algeria and Saudi Arabia to harvest the rainwater.
Zhu Qiang said the project is sustainable because it is spreading up in many areas with many individuals involved. People who does this can have the ownership and they can plan themselves whether they should build another cellar or not. The cost is very low, but very cost-effective and solve the real problem. The resource is from the sky, the labor is the local people's own labor. About 70% of the investment are invested by farmers themselves and they can afford it. It doesn't have any negative impact on environment. On the contrary, with the higher survival rate of trees due to the rainwater, it is good for the environment.
Zhu Qiang said even if people say there isn't high tech in the project, they used a lot of scientific methods in it such as testing the efficiency of the facilities and conduct evaluation. It is in fact a quite innovative idea to harvest rainwater and effectively use the resources from the sky.
Due to their practice, Chinese government has put the rainwater harvesting project into its 863 scientific and technological breakthrough program in order to solve the draught problem in more than half areas of China.
But Zhu Qiang still has some worries. First, he worries that with the big issue of climate change, extreme weathers come more frequently in China. That will be a big challenge for the future because suppose the rain doesn't come by the end of May every year, then the agriculture will definitely be affected as the rainwater can only support till then.
Second, so far the household water supply in Gansu's rural area is still very low. The average is just 20 litres per person per day. Third, how to further improve the water quality? Fourth, whether it is viable to use rainwater in agriculture? Or should people readjust their agricultural distribution? These are the issues which need further research.
Nevertheless, there are still many places that want to learn from this practice. Now even the Chinese capital Beijing are thinking of how to collect and make use of the rainwater and studied whether the practice in Gansu can be a good reference for Beijing.
As a rainwater harvesting expert, Zhu Qiang said such projects have been carried out in 15 provinces, autonomous regions and municipalities in north, northwest and southwest and coastal China, accounting for half of China's total areas. More than 21 million people have got their drinking water supply and about five million rainwater catchment systems have been built.
By Xuefei Chen, People's Daily Online Correspondent in Stockholm