Mr.Paolo MOLINARO, Technical Secretary of Q.74, ICOLD 19th Congress C/O ENEL-CRIS Via Ornato 90/14 20162 MILANO, ITALY By fax: to 39-2-7224-8450 [total 6 pages]
Dear Mr. Molinaro,
The role of the Technical Secretary is complex and I am apologizing for adding a last minute "headache" with the request to submit the content of this note to the session officers of Question 74.
Because of last minute cancellation for participation to the congress, the intervention may be presented formally by an other delegate*.
Preference is that the intervention content be provided to the officers that may use parts they will consider for conclusion or to be mentioned to the attendants of the Q.74. Also the content could be considered as a written intervention to be included in the discussion section in the volume 5 of post congress publication.
Some references made in the intervention may not be readily available or known. The intervener attached copies of parts from where they are originated, and a bibliography to the intervention is included [which may not be necessary to be included in the published intervention format].
Dear Mr. Moliniaro, please confirm receiving this fax. Thanks. Thanks for the attention on the subject, and wish success on your undertaking.
Dr.Thomas Vladut, P.Eng.
Mr. J.R. WILLIAMSON, Chairman,
Mr. Yong Nam YOON, Vice-Chairman,
Mr. Prof. P. RISSLER, General Reporter,
Subject: Reservoir Induced Seismicity (RIS); other concerns on reservoirs were addressed in the paper in Water Power, March 1997, pages 28-30.
Dear Gentlemen,
Discussions on RIS at San Francisco Congress 1988 [ Q 60] were summarized, by the General Reporter ( L.O.Timblin, of US Bureau of Reclamation ) as: "technological progress had been made in many areas related to the environment, including reservoir-induced seismicity measurement and prediction techniques." {1}
The positive view provided applications for two coming developments, for Eartan (China) and Katze (Lesotho). The risk identification got confirmation for the second site in 1996.
The issue of RIS has several aspects, and is a potential nuisance for any large dam development through the social concerns often used by anti - dam groups. Other aspects of RIS incidence are connected with several aspects of dam safety and environmental issues. At this stage the issues of RIS in practical terms continue to be still somehow neglected issue, and examples could be given, if not else for the unaware residents around Katse reservoir who had their houses affected, when no mitigation of risk was done for a site predicted to be at risk [Water Power 1993, issue May, page 33] along with others ie: Ertan.
"Truly, the nation was shocked to learn of the Mapeleng tremor while to the Mapeleng people the incident was a real nightmare." {2} In the surrounding area of Katze dam provision of temporary housing for seriously damaged and repairs compensate for the 54 dwellings affected. The rehabilitation program includes replacement for affected springs, a voluntary relocation program and assistance for increasing earthquake resistance of buildings and an income restoration program.
Most practitioners will report for new impoundments that monitoring procedures are in place. Monitoring is a good contramesure for continued or increased seismicity but lack the prevention component make the cost of monitoring questionable. Risk mitigation might achieved by more complex undertaking like the application of Risk Prediction Model (RPM) endorsed at the discussions for Q.60 at the 16th Congress in San Francisco and supported by four confirmed impoundment RIS at La Grande Quebec (LG2-LG4) and Katze(Lesotho).
Conclusions of the International Symposium on RIS, "ISORIS'95" held in China (associated to they large dam development program) suggested that RIS will be part of any future very large dam (VLD) impoundments. Suggestions were made that increased risk are associated as higher dams are required for economic water storage.
To alleviate the hazard of triggering RIS for new impoundments, risk identifications are available, based on the questionnaire distributed for the World Survey on RIS and Q.51 (Seismic Design for Dams). Impoundment of reservoirs with risk of RIS can develop specific mitigation programs as supported by RPM and other risk assessment procedures.
To enhance this environmental control program, hazard identification is offered free (contact the author by fax 403-250-6711 or E-mail at retom@cadvision.com) with cost recovery and support to be gathered from interested development agencies and organizations dedicated to enhance environmental concerns, ie: UNEP, UNCED, financial institutions like the World Bank and other development support organizations.
The hazard of RIS may be associated to new VLD under development, mostly when the reservoir volume is of significance (larger than one Km cub) and depth is larger than 100m. To note the average depth of further new reservoirs (using Mermel's definition of VLD) is increased with approximately 30 meters (146m for the next 130 VLD) and by this increased incidence of undesirable seismicity may be expected. Increased social sensitivities on environmental issues imply that lack of full scientific certainty shall not be used as a reason for postponing measures to prevent environmental treats, and probably RIS issues might be counted in this concern. Complacence related to RIS may derive from the fact that environmental decision-making is based on perception of risks, threats to the dam-structure compensated by advances of seismic design of dams. The RIS hazard estimate must be extended to the risk aversion of threats to biosphere and social structures.
Precautionary and mitigation approaches shall be widely applied according to the developer capabilities. The role of international organizations is to provide technology transfer where needed. The induced-seismic question is of such complexity, but no mechanism (technically and financial) is available for such issues. For most projects, probably including Katze, new teams try to wrangle with multiple environmental questions, and structured technology transfer is needed in a more structured format to be able to face the new challenges.
The unprecedented attention given to the ecological issues makes imperative the strive for redefinition of the concept of environmental security. Most hydro developments were developed on a relative idea of impact mitigation on a regional scale. But new global views change the scale of environmental security and critics on dams, with a relative regional mandate, analyze and criticize on demands for much larger concerns, to a much different scale of interferences, traditionally not addressed by regional or local analysis and design. Even environmental successful developments come under "environmental scrutiny" by changing the scale in time and space. The problems became more out of the traditional development design concern, ie: "change in the character of primary production (shifts in phytoplankton composition) in the Black Sea, resulted from decreased dissolved silica discharged from the Danube due to the Iron Gate Dam, some 1,000 km away,"{3} to more esoteric ones as changes in rotation velocity of the globe generated by the water mass of large reservoirs.
An engineering-scientific entity may address how changes in dams may be achieved and to provide systematic technology transfer for mitigation of environmental risks, ie: RIS, as needed to new projects. Such tasks are well beyond traditional design, and ICOLD endorsment might open new ways of solving this "global environmental security"issue.
* PS. Please if presentation by an other delegate is preferred, just contact my by fax [403-250-6711]. Thank you.