No abstract available

[en] Investigations were undertaken at the proposed Mangi Dam area by means of radiotracers to understand the subsoil hydrology. In all, seven radiotracer injections were made. It was established that there is a general underground water-bearing strata in the area and that the direction of the subsoil water flow is towards South-South West. The source of the springs down-stream of the dam axis is the regional groundwater. The water of the springs can be utilized for supplementing the dam reservoir provided adequate measures are taken to prevent any leakage from the reservoir. There are strong indications of the presence of an underground reservoir of a considerable size in the synclinal basin. This needs further investigations

No abstract available

[en] A conference was held to discuss dam safety. Papers were presented concerning public policy and legislative issues, standards, guidelines and criteria, dam safety reviews, operations and maintenance, technical issues, and case histories. Separate abstracts have been prepared for 18 papers from the conference

[en] The structural safety of concrete gravity dams and spillways during major floods was discussed, concentrating on failure mechanisms, the methodology for hydrological safety evaluation for existing dams, the notion of imminent failure flood, the resistance to overtopping and the effects of floating debris. In particular, the incidence of overtopping on structural stability of typical gravity dams was investigated using a variety of assumptions concerning the peak and residual shear strength parameters of construction joints according to CDSA guidelines. Some considerations regarding rehabilitation techniques to increase the hydrological safety of gravity dams and spillways, such as functional safety analysis of electro-mechanical equipment of gated spillways in case of major floods, emergency planning, and the availability of qualified personnel to ensure the safety of the installation, were also discussed. 19 refs., 8 figs

[en] A generic classification for the different methods used in rock drilling and overburden drilling is described, along with a classification of the range of grouting materials available and the different grouting methods that can be used. Examples are presented from two recent major dam remediation projects to demonstrate the basis for selection and use of the different methods and materials. It was shown that a high level of performance can be obtained when a project is properly designed, executed and monitored. 29 refs., 5 tabs., 5 figs

[en] No commonly used framework exists in the scholarly study of the social impacts of dams. This hinders comparisons of analyses and thus the accumulation of knowledge. The aim of this paper is to unify scholarly understanding of dams' social impacts via the analysis and aggregation of the various frameworks currently used in the scholarly literature. For this purpose, we have systematically analyzed and aggregated 27 frameworks employed by academics analyzing dams' social impacts (found in a set of 217 articles). A key finding of the analysis is that currently used frameworks are often not specific to dams and thus omit key impacts associated with them. The result of our analysis and aggregation is a new framework for scholarly analysis (which we call ‘matrix framework’) specifically on dams' social impacts, with space, time and value as its key dimensions as well as infrastructure, community and livelihood as its key components. Building on the scholarly understanding of this topic enables us to conceptualize the inherently complex and multidimensional issues of dams' social impacts in a holistic manner. If commonly employed in academia (and possibly in practice), this framework would enable more transparent assessment and comparison of projects.

[en] One of the key components of Ontario Hydro's Dam Safety Program is the Emergency Preparedness and Response Plans (EPRP). Preparing such a plan is time consuming and costly. This paper presents a simplified approach to prepare preliminary or interim EPRPs. The interim EPRPs consist of only the most critical components namely notification plans, action plans and interim inundation maps. The interim inundation maps are developed using simplified methods, assumptions and techniques. They provide a conservative but realistic estimate of the flooding that could occur as a result of a dam breach. Interim EPRPs can be produced in a fraction of the time of full EPRPs and can therefore be implemented quickly. The process described in this paper represents a major saving in time over the production of full EPRP, yet it results in effective interim plans that can act as final plans for small dam owners who do not have the the resources to prepare a comprehensive plan. 5 refs., 4 figs

[en] Reconstruction of the existing dam and the restoration of an overflow spillway at the Abiti-Price Inc. paper mill site in Jonquiere, Quebec, following the 1996 Saguenay Flood, were described. A central cement-bentonite wall, founded partly on bedrock and partly on sensitive marine clay, was constructed. Using a fast-track design and construction approach, the project was completed within four months of the disaster. Details of the approach used to ensure the quality of the cement-bentonite wall and the results of post-construction monitoring of the dam were described. The most significant result is that no seepage or piezo metric pressures have been recorded downstream from the dam since the impoundment. 32 refs., 6 figs

[en] A report is presented on the safety of halting construction of the 40 m high Alameda Dam in Saskatchewan. Pursuant to a series of legal and administrative proceedings, Environment Canada has been authorized to order a halt in construction of the dam. The safety implications of such an action are reviewed, particularly to determine the embankment crest elevation at which construction could safely be halted for a period of up to three months. A description is presented of principal features of the dam, site condition as of July 1991, flood hydrology and routing through the project, considerations for determining the safe height of the dam, downstream effects, and desirable conditions for the 1992 flood season. It is concluded that any halt in construction of the dam would have serious implications with respect to downstream impacts as well as integrity of the dam during the 1992 flood season. Risk of overtopping the embankment, halted at elevation 545 m, during a spring flood would be of the order of 1:4, with economic consequences amounting to millions of dollars. At a level of 557 m, risk of overtopping is reduced to the order of 1:50 to 1:100, however downstream consequences of a breach increase substantially. 6 refs