Safety Evaluation Of Tuyamuyun Dam Complex – Uzbekistan

Project Name: SAFETY EVALUATION OF TUYAMUYUN DAM COMPLEX – SOUTH KARAKALPAKSTAN WATER RESOURCES IMPROVEMENT PROJECT

Country: Uzbekistan

Client: Ministry of Agriculture and Water Resources

Finance Source: Government

Tags: Uzbekistan, Local, HEPP, Assesment

Narrative Description of Project:

This work has been performed within the scope of the project South Karakalpakstan Water Resources Management Improvement Project (SKWRMIP) , under Addendum â„–2 dated February 8, 2013 concluded between the Project Implementation Unit for Water Infrastructure of Ministry of Agriculture and Water Resources of the Republic of Uzbekistan and the Consortium Mott MacDonald and Temelsu International Engineering Services.

The SKWMIP area lies within three southern districts of Autonomous Republic of Karakalpakstan, namely Beruni, Ellikala and Turtkul at the tail end and on the right bank of Amu Darya. The total irrigated area of about 100,000 ha fed by the system of canals fed from SKRB taking water from the Tuyamuyun Reservoir

The main tasks which will be carried out during Assignment A of the project are:

1. to prepare a comprehensive long term analysis of the need to improvement the South Karakalpakstan Right Bank (SKRB) Irrigation and Drainage System for better water management;
2. to prepare a detailed feasibility level study with tender designs of the project (SKWMIP), which would meet the appraisal requirements of an internationally funded project under the first phase of the assignment.

 

Safety Evaluation of Tuyamuyun Dam Complex:

The main purpose of this Dam Safety Improvement and Smooth Operation Project is to review the issues of dam safety of the Tuyamuyun Dam on the basis of:

1. Analysis of existing observational data on the condition of structures;
2. Analysis of the carried out research;
3. Analysis of the operation and technical maintenance system;
4. Analysis of emergency preparedness.
5. Visits to hydraulic structures of Tuyamuyun system with studies of the process of operation and conducting the interviews with the representatives of Service Company.

 Objectives

The main objective of this task is to review the safety aspects of Tuyamuyun dam using the PFMA approach (see description below).

Outputs of the task are:

1. Review the operation and maintenance system; assess needs for improving/ modernizing monitoring and instrumentation;
2. Revise and/or prepare dam safety plans (Operation and Maintenance Plans; Instrumentation Plans; Emergency Preparedness Plans);
3. Conduct a liquefaction potential analysis of the foundations of Sultansandjar Dam;
4. Preparing terms of reference for the introduction of a Decision Support System
5. The PFMA process involves dam operators as main actors and provides the opportunity for on the job training.

 

 The specific purpose of the task is to:

1. Enhance the dam safety inspection process by helping to focus on the most critical areas of concern unique to the Tuyamuyun Reservoir System;
2. Identify operational related potential failure modes and structural related potential failure modes (e.g. piping) not covered by the commonly used analytical methods (e.g. slope stability, seismic analysis);
3. Enhance and focus the visual surveillance and instrumented monitoring program;
4. Identify shortcomings or oversights in data, presentation of data, information or analyses necessary to evaluate dam safety and each potential failure mode;
5. Help identify the most effective dam safety risk reduction measures.

 

Description of Actual Services provided by TEMELSU:

1. Collecting all data, studies and information on the investigation, design, construction, analysis, performance and operation of the project. All studies and investigation reports existing that relate to the ongoing safety of the dam were included and reviewed and evaluated.
2. Visiting the project site with an eye out for potential failure modes, structural and geologic conditions, review operations, and interview owners/operators for their input on potential failure modes.
3. Reviewing all the background information for general understanding and with the following questions in mind:

• How could this part of the works fail? (site-specific consideration of geology, loadings, structure condition, and project operations ),
• What would happen if it fails?
• Are the identified potential failure modes recognized and being appropriately monitored by visual surveillance or instrumental monitoring?
• What actions (immediate or long term) can be taken to reduce failure likelihood or to mitigate failure consequences? These actions could include any of the following: data collection, analysis or investigations, operational changes, communication enhancement, monitoring enhancement and structural remediation measures.
  4. Performing site specific seismic evaluations with Probabilistic Seismic Evaluation Methods to determine the seismic analyses parameters in conformity with the state of the art ICOLD Seismic Criteria,
  5. Analyzing the stability of the Tuyamuyun Dam under static and dynamic loads for the Seismic Hazard Assessment das defined above, including liquefaction analysis under different earthquake hazard levels;
  6. Considering requirements for ongoing structural monitoring of the Tuyamuyun dam, including an assessment of existing monitoring equipment and recommendations to augment or repair/replace existing equipment;
  7. Prioritizing required rehabilitation or repair works in accordance with risk based criteria;
  8. In identifying the proposed rehabilitation measures, the emphasis will be given to those works considered essential to ensure the sound operation and integrity of the dam and its appurtenant structures. A phased procedure for risk assessment process will be followed:
  9. Assessment of Structural Adequacy. This will involve assessment the likelihood of failure of the dam under design loading conditions, and will be determined principally by foundation and embankment material strengths and drainage conditions.
  10. Risk Analysis. This process involves examining all the potential defects which may contribute to the risk of dam failure, and arranging them into sequences which cover all possible or reasonably possible failure modes. Occurrence risks are assigned to each of these factors to derive an overall risk of failure of the dam.
  11. Prioritized Remedial Works. This will cover comparing the consequences of dam failure risks and their possible impacts, the remedial works necessary to reduce the these risks, thus prioritizing the measures that should be provided for dam safety improvement confirming the state of the art standards.
  12. Potential Failure Mode Analyses (PFMA ) have been performed in following steps:
      1. i) Designation of the Potential Failure Mode Analysis Participants
      2. ii) Collection of Background Data on the Dam for Review by the Core Team

• iii) Site review including interviews with key owner personnel at the Project. (Core Team)

1. iv) Comprehensive review of all of the Background Data on the Dam by the Core Team
2. v) Conduct of the PFMA Workshop Session (the Facilitator for assuring the process is followed, and the Core Team for performing the PFMA)
3. vi) Consideration of Surveillance and Monitoring opportunities and/or Risk Reduction measures for Identified Potential Failure Modes

• vii) Documentation of the PFMA and Surveillance and Monitoring and/or Risk Reduction opportunities

13. Preparation of the Final report, including:
    1. i) Input to dam safety plans (Response Level Matrix in particular),
    2. ii) Dam safety plans (Instrumentation, O&M, Emergency Preparedness)

• iii) Rehabilitation and Strengthening measures for improving the Seismic Safety of the Tuyamuyun Hydro-system,

1. iv) Recommendations on training needs for dam operators and other relevant stakeholders.
2. v) Terms of reference for the introduction of a Decision Support System