敦煌莫高窟保护区洪水预测预防研究

1.兰州大学 资源环境学院,甘肃 兰州 730000; 2.敦煌研究院,甘肃 敦煌 736206; 3.甘肃省环境应急与事故调查中心,甘肃 兰州 730030

大泉河; 洪水预测; 莫高窟

Research of flood forewarning and preventing in Dunhuang Mogao grottoes reservation
XUE Li-yang1,3,BEN Lian-fang1,ZHANG Ming-quan1,WANG Xu-dong2,GUO Qing-lin2,LIU Hong-li2,WANG Xiao-na1, MA Hong-hai1

(1.Collede of Earth and Environment Sciences,Lanzhou University,Lanzhou 730000,China; 2.Dunhuang Academy China,Dunhuang 736206,China; 3.Gansu Province Center of Environmental Emergency and Accident Investigation,Lanzhou 730030,China)

Daquan river; flood forewarning; Mogao grottoes

DOI: 10.13800/j.cnki.xakjdxxb.2017.0210

备注

敦煌莫高窟保护区所在区域气候极为干旱,但受到早年多次洪水影响,致使洞窟潮湿、壁画霉变、酥碱,对国家重点文物保护造成极大威胁,因此通过窟前大泉河洪水预测的研究,分析和预测不同降水条件下的莫高窟库前洪水流量,进一步合理制定洪水防范措施和风险预警体系,对保障莫高窟文物安全具有重要的实际意义。通过对莫高窟保护区实地考察和流域特征分析,选择短缺流量资料地区比较适宜的瞬时单位线法,分别测算出大泉河野马山、一百四戈壁和三危山50 a,100 a,500 a一遇的洪水流量,以此为基预测2种不同降雨情形下的洪水流量。①当降雨从上段野马山区开始,依次向中段、下段移动时,50 a,100 a,500 a一遇降水流经大泉河莫高窟前断面的洪水流量分别为230,463,757 m3/s; ②当全流域同时降雨时,50 a,100 a,500 a一遇降水流经大泉河莫高窟前断面的洪水流量分别为230,330和510 m3/s.并通过实际发生的2次百年一遇的洪水的洪峰流量和气象条件与测算数值进行比对,印证预测结果可信。同时,为了提高莫高窟抵御洪水风险的能力,确保莫高窟文物安全,防患于未然,进一步提出了建立健全流域降水和洪水监测体系、开展大泉河防护性工程建设、降雨洪水预警体系建设和石窟作防雨防渗等措施的建议,以便有效预防洪水,切实保障莫高窟安全。

The regional climate is extremely dry in Dunhuang Mogao Grottoes conservation area.However,the floods occurring repeatedly in the early times resulted in humid caves,moldy crisp and alkalescent murals,posing a great threat to the national key cultural relics protection.Therefore,we should take further measures to prevent floods,analyze and forecast the flood discharge of the Mogao Grottoes under the different precipitation conditions,to improve the risk warning system by predicting the flood time of Daquan River in front of the caves so as to ensure Mogao Grottoes'security.In this study,based on the field investigation and analysis of river basin characteristics,we appropriately predicted the rainfalls on Daquan River YeMa Mountains,140 Gobi and Sanwei Hill at years of 50,100 and 500,respectively,by an instantaneous unit hydrograph method which suits for regions shortage of flow.The flood flows were calculated when these rainfalls occurred at two places:①when rainfall starts from the mountains in the upper Mustang,followed by to the middle and lower sections of mobile,the flood flows were 230,463 and 757 m3/s at years of 50,100 and 500,respectively; ②when the rainfall starts at the whole basin,the flood flows were 230,330 and 510 m3/s at years of 50,100 and 500,respectively.The prediction result is confirmed to be reliable according to two actual 100 year flood peak discharge,meteorological conditions and numerical estimates.In order to improve the ability of Mogao Grottoes to resist flood risk,to ensure the safety of Mogao Grottoes,and to prevent and take preventive measures,we puts forward the measures to establish and improve the basin precipitation and flood monitoring system,carry out large spring river protection project construction,rainfall flood warning system construction and rainproof and seepage controlling for caves.So that to be effective in preventing floods,and effectively protect the safety of the Mogao Grottoes.