REPUBLIC OF TAJIKISTAN

REQUIREMENTS

Sarez Lake is located in the Rushon District of the Gorno-Badakhshan province, Tajikistan. The lake was created by a massive landslide triggered by a high intensity earthquake in 1911. The landslide created the Usoi Dam (650m high), the highest dam in the world, either natural or man-made. The lake that formed behind the dam initially rose at a rate of approximately 75m/year and drowned the village of Sarez, after which it was named. The lake has no natural outlet and as a result there is concern that the failure of the rubble heap dam would have a significant impact of the habitants who live directly downstream of the natural Usoi Dam.

Within the framework of the Lake Sarez Risk Mitigation Project (LSRMP), CAE and its local partner are responsible for an update of the current monitoring and Early Warning System (EWS), established between 2003 and 2006, as it is approaching the end of its design life. The project, financed by the Asian Development Bank (ADB), will help the Committee of Emergency Situation and Civil Defense of the Republic of Tajikistan in managing the risk associated with Usoi dam and Sarez Lake in Pamir region. The new monitoring and EWS is expected to protect communities downstream of the dam,where 5 million peopleliving in 4 different countries (Tajikistan, Afghanistan, Turkmenistan and Uzbekistan) may be affected by the potential outburst of Sarez Lake.

FEATURES

The contract scope includes the supply, installation, and commissioning of the monitoring and EWS that will enable real time and reliable monitoring of Sarez Lake’s right and left banks, as well as upstream and downstream rivers for data gathering, EWS activation and communications with control centres.

The approach to the early warning and monitoring system was based on triggering effects and the concatenation of possible triggering events for the Usoi Dam and the Sarez Lake, respectively. The main triggering events considered were a right bank slide, an earthquake affecting the dam or causing an increase in water level in the lake, the dam overtopping by a wave due to either a significant landslide into the lake proper and the internal disturbance of the dam. Most of the triggering events are not mutually exclusive.

The triggering events to be monitored in the contract:

• Right bank and left bank slides;
• Earthquakes;
• Sarez Lake level;
• Community EWS;
• EWS System, Communications and Data Centre (SCADA);
• Communication centres at Sarez Lake and at Dushanbe.

Sarez lake sites, located at the altitude between 2.600 and 3.000 m a.s.l., are only accessible with helicopter or by a 24-km walk. It represented a challenging task for CAE in managing the logistics, installation and operation. Due to the lack of the electricity network and mobile communication network in most of the sites, the monitoring stations and EWS communication are powered completely by solar panels and rechargeable batteries, with data transmission via Eumetsat satellite transmitter.

COMPOSITION

The new Sarez Lake monitoring and EWS include GPS units, strong motion accelerometers, submersible pressure sensors, drone, radios, satellite phones, automatic weather station, hydrological stations, hydrometric stations, and others.

In particular:

• n.3 Strong Motion Accelerometer (SMA): to monitor seismic activity relating to earthquakes;
• n.4 GPS receivers: to be used for manual observations for the right and the left bank slide of the lake.
• n.1 Lake Hydrometric Station: to monitor water level and wave height of Sarez Lake by means of pressure water level sensors;
• n.1 Automatic Weather Station (AWS): to monitor local weather conditions of Sarez Lake with a complete set of sensors including thermo-hydrometer THS, rain gauge PG10, snow depth sensor ULM30/N, wind speed and direction, solar radiation, and atmospheric pressure, etc.
• n.2 Automatic Hydrological Stations: to provide observations on current conditions and early warning of flood conditions above and below Sarez Lake, with WLR/S Radar hydrometer.
• EWS Communication System composed of n.30 manually-triggered sirens for the communities up to 300km downstream of the Usoi Dam.
• N.2 data centers equipped with hardware and CAE software suite, including DATALIFE, AEGIS, PatrolME, etc. for managing data from SMA, hydrological stations and trigger alerts to communication centres;
• n.1 Drone: for remote monitoring of sites in the lake proper and below the dam;
• n.1 ADCP, n. 1 salt dilution technique equipment and 2 Surveyors Levels: for Discharge measurements and direct water level readings;

In addition to the supply of the specialized equipment, CAE provided a full range of services such as project design, system integration, equipment installation and commissioning, transport, testing as well as classroom and on-site technical training, etc.

The completion of the project, which is considered of strategic importance for the country of Tajikistan, once again confirmed CAE’s preparedness at the forefront in the mitigation of natural risks.