Rainwater Harvesting: All You Can Catch

by Beate Engelen

Amity brought rainwater harvesting technology to farmers living on the parched Loess Plateau of southern Gansu. Today, several million local people use this technique as a means to survive even severe droughts. But water scarcity remains a problem.

The terraced hills of Anding are coated in lush green patches; tiny wheat fields pile up layer by layer as far as the eye can see. At first glance one cannot make out that the wheat sprouts, swaying in the winds of early June, may soon shrivel under the torching summer sun. This place in southern Gansu Province is part of the vast Loess Plateau and one of the driest places in China – only the deserts of Xinjiang have less water. Here, the yellow river runs far to the north and the bone-dry yellow earth holds no groundwater. There are no wells near the fields and no irrigation ditches have been carved out of the hardened soil. It soon becomes clear that crops, animals and the people of the hills all rely on rain and dew for moisture.

At 380 mm, annual rainfall in Anding lingers just above the minimum amount needed for growing crops without artificial irrigation. Even when it rains, little water can be absorbed by the solid soil. Most of it quickly runs off unobstructedly through the deep gullies and ravines which cut through the terraced hills. People in the area have become austere when it comes to water consumption. They use only one fifth of the amount of water used by people in other parts of China. Though the irrigated area has increased over the years, most people in the hills have no access to irrigation water, and even their access to drinking water is not reliable. The consequences are obvious: Lack of water is considered the number one factor responsible for severe poverty in Anding.

Unreliable rainfall

What makes survival in the terraced hills more difficult than in most other places is the unreliable timing of rainfalls. For farmers to be able to harvest wheat and corn at the end of the season, it is not enough that sufficient precipitation occurs overall during a year. Rain needs to fall at the right time to water the sprouting crops and regularly provide farmers with drinking water for themselves and their animals. But in spring, when the plants need water most, precipitation tends to be scant, only to become more frequent in late summer when crops don’t need so much any more and the water only contributes to the galloping erosion of the hills.

In the past, years of droughts or uneven rainfall meant hardship, hunger and even death. For farmers of the arid hills, water insecurity runs back far into historical times. Local records note 634 droughts over a period of 1400 years, with the frequency of dry spells getting higher in recent years. Almost every other year, people faced severe water scarcity, which caused agricultural productivity to drop sharply.

A wake-up call

So it was until 1996. The year before had seen one of the harshest droughts in sixty years. Around three million people on the Loess Plateau of Gansu and two million animals were left without water. Authorities needed to act. It was during this time that effective technologies were finally implemented to collect and store rainwater.

The Gansu Research Institute for Water Conservancy had already experimented with rainwater harvesting methods as early as 1988 but funds had never been granted to extend the project beyond the scientific testing grounds. The drought of 1995 gave the authorities a sufficiently strong incentive to go looking for the necessary funds and get serious about the “121 Rainwater Catchment Project”. Approached by the provincial Water Engineering Department, Amity – among other organizations – agreed to join the project, which eventually became a breakthrough in dryland farming and won international fame.

The project targeted villagers in 6 arid counties with neither groundwater nor runoff, says Xie Ying, head of Amity’s record archive. Each participating family agreed to three changes in their immediate environment. First, the farmhouse roof and courtyard, commonly used for drying crops, were paved with cement to make a good rainwater collection surface. Likewise, two underground water cellars between 15 and 20 cubic meters in size were built to contain the water collected on the cement tile roof and in the courtyard. And finally, one small garden plot near the farmhouse was created to be irrigated using water-saving methods. Farmers used this plot for growing cash crops and hence raising income levels.

Bringing water to millions

The project became hugely successful. At its inception, the project provided over 82,000 people and 40,000 livestock with reliable access to drinking water. Today, several million farmers rely on the technology Amity helped to introduce in the mid-nineties, says Qiu Jie, head of the Women’s Hospital in the provincial capital Lanzhou and an Amity partner for many years.

One of these farmers is 46-year-old Wei Yao from Lijiabao in Anding. He is the proud owner of a rainwater catchment system. He keeps the surface of his farmyard painstakingly clean to make sure that – if it rains – water running into the underground cellars remains largely uncontaminated. However, it takes some time for the sediments to settle after rainwater is washed in and water also needs to be boiled before it is used for consumption.

At present, Mr. Wei’s two underground cellars of 15 cubic meters each are big enough to provide his family with drinking water for 8 to 10 months in a normal year. Only during a dry spell does he rent a small vehicle to buy water from a place 8 miles away. What he can buy for CNY 80 (US$ 11) provides him, his family and their livestock with drinking water for one month.

However, although water is more easily available now the rainwater catchment system has been installed, Wei Yao’s family saves water wherever and whenever they can. For them, taking a shower or washing clothes remains a luxury they seldom indulge in. Farmers in the hills of the Loess Plateau are still clearly underprivileged in comparison with city residents in the same area.

Inequalities in water consumption

The rural-urban divide, a current policy tenet which, in many areas of daily life, staunchly favors city dwellers over people in the countryside, is evident in the way water resources are allocated. In 2006, city folks in central Gansu Province were entitled to use an average of 80 liters of water per day whereas people in the countryside were expected to use no more than half this amount, according to a study by Lu Caizhen, a social scientist who has researched water use in Gansu. This disparity is justified by the assumption that urban residents take showers and use water toilets frequently whereas villagers don’t. But why don’t they? The reasoning doesn’t hold up when farmers are asked for their opinion – they feel it’s utterly unfair.

Landscape in Anding. Only the deserts of Xinjiang are drier.

In the end, water scarcity will affect everybody in Gansu in one way or another. Around the district center of Anding, where groundwater is still available and residents enjoy running water from underground sources, the water table is dropping rapidly. One district official has estimated that, in no more than ten years’ time, water will have dried up completely. It is as yet unclear what will then happen to the people. Some residents have moved up north to Dunhuang near the ice-capped Qilian mountain range, where ground water is still available. But the city has already become wary of all the environmental refugees pouring in from the south. No more people from dried-up regions are accepted in.

Where will the Anding city dwellers turn for water now? Nobody knows. As long as rainfall remains stable in Anding, at least the farmers in the hills will survive for a while. The next decade will show if things will stay like this in spite of climate change.