Water is one of the most dynamic forces of nature. But, at times, why does this savior of humankind become the destroyer? This question has been haunting civilizations for centuries. It is of special importance to China because 70 percent of its cities are situated and about 700 million of its 1.3 billion people live in disaster-prone areas, many of which face the wrath of excess water or the lack of it.

"The history of China is almost a chronological record of natural calamities", says Wang Yongjie, professor of wetland studies at Qiqihar University in Heilongjiang province. "If floods have shaped many characteristics of early Chinese civilization, floods and water crises in modern China, to a large extent, manifest the conflicts between human activities and nature."

Water can trigger a series of tricky situations in the ecological system. Water spaces or natural bodies such as flood plains, forests and wetlands, which help preserve and recycle water, play an important role in maintaining the integrity of water resources. Wang says: "To maintain the water cycle, water spaces are the foremost tangible frontiers for humans. The floods and calamities that water causes can be avoided or even used to our advantage if we reflect on our actions in relation to water spaces."

Most Chinese turn a blind eye to the cause-and-effect relationship between floods and humans. "They don't realize that a flood, a dynamic state of water, is also a source of freshwater, which plays an important role in adjusting the water system of drainage areas, especially for a country like water-scarce China. The huge loss caused by floods is partly related to our immature understanding of floods," Wang says.

Flood plains generally refer to flat alluvial land in the middle and lower reaches of a river. Protecting flood plains and making them sustainable are crucial to minimizing the effects of floods.

But flood plains are only one type of water space. Forests and wetlands are equally important for ensuring water regeneration and balanced distribution. Wang says that the main problem with China's water space is the conflict among its population, resources, environment and development elements.

"The unfettered urbanization drive is pouring billions of tons of cement and other solid waste into waterways. Urbanization has also transformed land from being an indispensable part of ecology into property." For example, humans have cleared swathes of forests in Heilongjiang. In real terms, Heilongjiang's forest cover has dropped from more than 70 percent in the early 1900s to 35 percent today. Three-fourths of the forests in the upper reaches of the Minjiang River in Sichuan province disappeared between the 1950s and 1990s. Hundreds of wetlands and lakes have been converted into farmland, and then into construction sites.

Also, 80 percent of the marshes in Heilongjiang's Sanjiang plains have been transformed into cultivable land in the past 50 years. And only 83 of the 983 natural lakes have survived the wrath of the past 60 years of economic development in Hubei province.

Damming a river and building levees along its course are the only ways known to humans to prevent floods. But levees don't leave enough room for river water to overflow and thus seep down to the underground water table and replenish the soil. They change the ecosystem of the drainage area, too, and shrink the cross-section of the drainage channels.

But embankments and levees, and even dams, are of no help when water levels rise above the so-called danger marks. These manmade structures allow water to gush out from rivers only when it reaches devastatingly high levels. Once that happens, all hell breaks loose with the overflowing water (flood) devastating lives and property in their path. Had there been no dams and embankments water would have flowed out at lower levels and found its way to the drainage basins, and thus caused much less devastation.

Flood plains that are less than 200 meters above sea level along the seven largest rivers of China are the most likely places to be flooded. These plains comprise one-third of the country's farmland, which is home to 600 million people and accounts for 60 percent of its GDP. The problem is we have not been able - and will never be able - to find a solution to this problem by trying to change the course of nature.

"The natural mechanism of flood plains cannot be recovered through artificial water-works projects such as dams and levees But how can sustainable development of the important areas be maintained and how can floods be prevented?" Wang says.

"Sustainable management of water resources is possible only if humans respect the integrity and functions of water space."

In other words, humans have to stop changing the nature and functions of natural bodies such as flood plains, forests, wetlands and lakes. We cannot reap benefits for long by changing the functions of natural bodies.

"Our efforts to transform nature will finally come back to us as punishment," Wang says.

As Friedrich Engels has said, "No disasters come without historical progress as compensation."

We Chinese believe a country will emerge stronger after adversities, but, that historical progress may not necessarily be in conformity with the modern concept of development.