Tibet-Nepal floods: China deploys satellites and drones as barrier lake breach risk grows

China has issued a LevelIV emergency alert following devastating flash floods near the TibetNepal border warning that a newly formed barrier lake at the confluence of two rivers faces a significant risk of breaching and triggering further flooding in downstream areasChinas Ministry of Water Resources issued the alert for the Tibet Autonomous Region on Thursday night citing concerns over the barrier lake that formed near the confluence of the Chhochen Khola and Purepu Tsangpo riversThe two rivers originate in Tibet and flow into Nepal as part of the Bhote Koshi river system Chinese authorities fear that a breach of the blockage could trigger another major disaster downstream potentially affecting border areas and settlements in NepalBarrier lake holds around two million cubic metres of waterThe newly formed lake had accumulated an estimated two million cubic metres of water as of Thursday morning staterun Xinhua news agency reportedContinued rainfall is expected to increase the pressure on the natural barrier According to forecasts inflows into the lake could add about three million cubic metres of water over the next three daysThe additional inflow could substantially increase the risk of the barrier breaching and releasing large volumes of water downstreamChinese authorities said such an event could cause further damage in areas including Gyirong Port near the ChinaNepal border and other locations downstreamAuthorities ordered to monitor rainfall and downstream risksChinas Ministry of Water Resources has directed local authorities to closely monitor the barrier lake rainfall and water inflowsOfficials have also been instructed to strengthen forecasting and risk assessments and identify people living in potentially affected downstream areasChinas natural disaster emergency response system has four levels with LevelI being the highest level and LevelIV the lowest Despite being the lowest formal emergency response level the alert reflects official concern over the potential consequences of a breach as water continues to accumulate behind the blockageSatellites and drones deployed for rescue operationsChina has deployed satellite and drone resources to support rescue and disaster assessment operations in the floodhit region near the Nepal borderThe China National Space Administration CNSA said it had mobilised satellite resources to conduct emergency imaging of the affected areas and retrieve historical imagery for comparisonSo far five images from before the disaster and 10 images taken after the floods have been provided to emergency response and disaster relief departments to assist with damage assessment and mitigationChina has also deployed its Wing Loong unmanned aerial vehicle equipped with highdefinition cameras for reconnaissance across the affected regionThermal imaging used in search for missing peopleRescue personnel are also using smaller unmanned aerial vehicles to support search operations in areas affected by flooding debris and mudThe highdefinition camera footage is being used to create threedimensional models of the disasterhit terrain The data is intended to help rescue command centres assess the overall situation and identify priority areas for search operationsThermal imaging equipment mounted on drones is also being used to detect human heatsource signals particularly in vegetated areas and zones covered by mud and debris according to the Xinhua reportDrone footage showed that the water level of the barrier lake had risen compared with Wednesday night Firefighters have also been using drones to mark points around the lakes perimeter and calculate its surface areaHundreds reported missing as barrier complicates rescue workAccording to Chinese authorities 558 people including foreign tourists went missing after flash floods struck Gyirong Port in Gyirong County near the TibetNepal border on August 26Rescue operations have been complicated by the formation of the barrier lake which authorities believe could trigger a major secondary disaster if it breachesAn eightmember advance team from China Anneng a stateowned engineering and rescue enterprise arrived in Gyirong County on Thursday with communications and detection equipment to collect key information and support efforts to address the upstream blockageRescue personnel said the accumulated debris located around three kilometres upstream of the port could only be cleared safely after the threat posed by the barrier lake had been addressedChinese Premier visits disasterhit areaChinese Premier Li Qiang visited the disasterhit region on Thursday along with senior officials from relevant departments to assess the damage and review ongoing rescue and relief operationsThe officials are expected to supervise the response and meet people affected by the disasterA directing group from the Peoples Liberation Army Western Theatre Command which is responsible for military operations in the Tibet region was also dispatched to coordinate joint rescue efforts involving military personnel in Gyirong CountyAuthorities are continuing to monitor the barrier lake as rainfall persists with efforts focused on reducing the risk of a breach while search and rescue operations continue in the floodravaged border regionWith inputs from PTI