LANZHOU, March 7 (Xinhuanet) -- Chinese hydrologists have forecast that the runoff of the Yellow River, the second longest waterway in China, will continue to drop in the coming 100 years due to rising temperatures and frequent droughts.

    The runoff of the river will reduce slightly before 2020 and but after 2050, the river's water flow will reduce by more than five percent every decade, according to research results released by hydrologists with the Lanzhou Yellow River Hydrology and Water Resources Research Institute in Northwest China's Gansu Province.

    Records show that the amount of surface runoff at the source of Yellow River stands at 20 billion cubic meters annually on average. If the river is to retain such a runoff in the coming 50 years, it needs a water supply of one billion cubic meters annually.

    However, research results show that water resources at the river source are likely to continue to drop when the factor of evaporation is taken into account, hydrologists said.

    Hydrologists with the Lanzhou research institute found that China has registered marked climatic changes in the last 100 years, with the temperature rising by 0.4 to 0.5 degrees Celsius, a little bit lower than the world's average of 0.6 degrees Celsius for the same period.

    They forecast that China's average temperature would rise by 1.7 degrees Celsius by 2020-2030 and by 2.2 degrees by 2050, leading to an increase in evaporation.

    Temperatures at the Yellow River source were comparatively low in the 1960s and 1970s, but rose by approximate one degree in the 1990s. Enditem