Economic Observer Online
August 1, 2012
By Chen Wenya (陈文雅)
Translated by Zhu Na
Original article: [Chinese]
The suburban district of Fangshan bore the brunt of the disastrous July 21st Beijing rainstorm. It later came to light that some badly flooded residential blocks there had been built on plains previously set aside as zones for flood diversion.
Now some people in Fangshan New Town worry about the safety of their properties.
The Economic Observer asked Gu Qun (顾群), a designer with China Water Resources Beifang Investigation, Design and Research Co. Ltd. (中水北方勘测设计研究有限责任公司), how property development could be allowed on flood-diversion zones.
In 2003, the Fangshan District local government authorized his company to make the Xiaoqinghe River (小清河) Flood-Diversion Zone Safety Construction Planning Report, which Gu was involved with. "If the government follows what we planned, there shouldn’t be any problems," he said.
Gu said developing properties in flood-diversion zones requires a scientific survey and planning for flood prevention. The Xiaoqinghe River Flood-Diversion Zone Safety Construction Planning Report guided Fangshan New Town’s planning starting in 2005. The project passed examination from the Beijing Municipal Water Resources Department, the Haihe River Basin Committee, and the Ministry of Water Resources.
Before the planning, roughly half of the land under the administration of Fangshan was mountainous, with the other half being flat plains. However, half of the plains areas were set aside as flood-diversion zones, which restricted many opportunities. "When Fangshan [local government] authorized us to do this planning, they hoped to achieve a balance between flood prevention and economic development," Gu said.
Adjustments to the range of the Xiaoqinghe River flood diversion zone were made with three "safety zones" added. Gu explained that during the planning a mock flood was computed for the whole diversion zone. The calculation found that two areas on the right bank of the Xiaoqinghe River (Zones I and II) and one to the left (Zone III) had higher ground and would be less impacted by flooding. Flood prevention and safety measures were set up so that Zones I and II could withstand a once in 100-years flood while Zone III could handle a once in 50-years flood.
A 750-meter wide pass where large-scale construction would be prohibited was established between the levee and the flood warning line for the three safety zones.
Gu worries though that not all of the projects have strictly followed flood prevention requirements. "In the planning we required the major and branch waterways of the Yongdinghe River and Xiaoqinghe River to be dredged," he said. "It was learned that the south of the Yongdinghe River and north of the levee have followed the standard. But some branch waterways haven’t been dredged, which is likely to have impacted the capacity for releasing flood waters."
He said the rainstorm caused the river outside a residential block in Changyang to break its levee, which caused major flooding. This may have been because the riverbed hadn’t been fully dredged. Additionally, it isn’t known whether the planning and design of the block fully complied with the Water Authority’s (水务局) flood impact assessment.
"Now some developers build properties very close to the river in order to make them near water,” Gu said. “That’s actually very risky."
Links and Sources
Economic Observer Online: Causes of Fangshan\'s Disaster