Large Dams

Megaproject Planning and Management: Essential Readings contains the seminal articles from the growing body of research on megaproject planning and management along with an original introduction by the editor, Bent Flyvbjerg. The leading and most cited authority in the field, Flyvbjerg has used crowdsourcing and 25 years of experience to cherry-pick from several hundred articles and books the writings that define the field. This volume will be an indispensable source for those wishing to speak with authority about how megaprojects are prepared, delivered, and fought over. The target audience is students, academics, practitioners, and media pundits alike, as well as communities affected by megaprojects.

Pore pressure within the core of the embankment dams play a decisive role in performance of the earth dams. Although it may be high during the construction stage of the dam, it will be dissipated to a reasonable level as the consolidation process of the core is progressing in the long term. However, if these dams experience heavy earthquakes in short time, the rapid increase of the pore pressure may put the dam at risk in some critical conditions. In this paper the Excess pore pressure development of the Karkheh large embankment dam during the earthquake loading has been investigated. The Karkheh Dam is the largest storage dam in Iran that has been recently constructed in the south-west of the country. This is an earth dam by a mixed clay core. The length of the dam crest is 3030 m and its maximum height at the river section is 127 m. In the analyses carried out in this study, the FLAC-2D was used. To prepare the initial requirements for doing the dynamic analyses, the dam was modeled from the beginning of the construction. Different construction stages and also the impounding stages of the dam were modeled by 32 stages from the beginning of the dam construction up to Dec.2004. After application of the selected accelerogram to the model and doing the dynamic analysis, considerable changes happen both in values and in the pattern of the pore pressure developments. The results of the dynamic analyses revealed that the value of the developed pore pressure at the mid. Levels of the core increases and its distribution pattern changes during an earthquake.

This article presents results from the first statistically significant study of cost escalation in transportation infrastructure projects. Based on a sample of 258 transportation infrastructure projects worth US$90 billion and representing different project types, geographical regions, and historical periods, it is found with overwhelming statistical significance that the cost estimates used to decide whether such projects should be built are highly and systematically misleading. Underestimation cannot be explained by error and is best explained by strategic misrepresentation, that is, lying. The policy implications are clear: legislators, administrators, investors, media representatives, and members of the public who value honest numbers should not trust cost estimates and cost-benefit analyses produced by project promoters and their analysts.

During World War I, the US Congress made it unlawful to speak against the war. The executive prosecuted many for doing so and when tried at the Supreme Court it upheld the sentences. During the Iraq War it was not a crime to speak against the war, but it was almost impossible to be heard if you had anything critical to say. Mass media practiced a self-imposed censorship. The op-ed below was written a few days after the invasion of Iraq and sent to main media in the US, but none wanted to print it on the grounds that critique of the war was considered untimely.

Dan Lovallo and Daniel Kahneman must be commended for their clear identification of causes and cures to the planning fallacy in “Delusions of Success: How Optimism Undermines Executives’ Decisions” (July 2003). Their look at overoptimism, anchoring, competitor neglect, and the outside view in forecasting is highly useful to executives and forecasters. However, Lovallo and Kahneman underrate one source of bias in forecasting—the deliberate “cooking” of forecasts to get ventures started. My colleagues and I call this the Machiavelli factor.

Results from the first statistically significant study of the causes of cost escalation in transport infrastructure projects are presented. The study is based on a sample of 258 rail, bridge, tunnel and road projects worth US$90 billion. The focus is on the dependence of cost escalation on: (1) the length of the project‐implementation phase, (2) the size of the project and (3) the type of project ownership. First, it was found, with very high statistical significance, that cost escalation was strongly dependent on the length of the implementation phase. The policy implications are clear: decision‐makers and planners should be highly concerned about delays and long implementation phases because they translate into risks of substantial cost escalations. Second, projects have grown larger over time, and for bridges and tunnels larger projects have larger percentage cost escalations. Finally, by comparing the cost escalation for three types of project ownership - private, state‐owned enterprise and other public ownership - it was shown that the oft‐seen claim that public ownership is problematic and private ownership effective in curbing cost escalation is an oversimplification. The type of accountability appears to matter more to cost escalation than type of ownership.

The Supplementary Green Book Guidance on Optimism Bias (HM Treasury 2003) with reference to the Review of Large Public Procurement in the UK (Mott MacDonald 2002) notes that there is a demonstrated, systematic, tendency for project appraisers to be overly optimistic and that to redress this tendency appraisers should make explicit, empirically based adjustments to the estimates of a project’s costs, benefits, and duration. HM Treasury recommends that these adjustments be based on data from past projects or similar projects elsewhere, and adjusted for the unique characteristics of the project in hand. In the absence of a more specific evidence base, HM Treasury has encouraged departments to collect data to inform future estimates of optimism, and in the meantime use the best available data. In response to this, the Department for Transport (henceforth DfT), has contracted Bent Flyvbjerg in association with COWI to undertake the consultancy assignment "Procedures for dealing with Optimism Bias in Transport Planning". The present Guidance Document is the result of this assignment.

As megaprojects have become ubiquitous, their real benefits and costs have come under increased scrutiny. We interviewed Bent Flyvbjerg, who has extensively studied megaproject development. Flyvbjerg has found systematic problems in the development process: by intentionally misrepresenting information and deliberately disregarding risks, proponents instigate projects that result in fewer benefits and higher costs than promised.

This article presents results from the first statistically significant study of traffic forecasts in transportation infrastructure projects. The sample used is the largest of its kind, covering 210 projects in 14 nations worth U.S.$59 billion. The study shows with very high statistical significance that forecasters generally do a poor job of estimating the demand for transportation infrastructure projects. For 9 out of 10 rail projects, passenger forecasts are overestimated; the average overestimation is 106%. For half of all road projects, the difference between actual and forecasted traffic is more than ±20%. The result is substantial financial risks, which are typically ignored or downplayed by planners and decision makers to the detriment of social and economic welfare. Our data also show that forecasts have not become more accurate over the 30-year period studied, despite claims to the contrary by forecasters. The causes of inaccuracy in forecasts are different for rail and road projects, with political causes playing a larger role for rail than for road. The cure is transparency, accountability, and new forecasting methods. The challenge is to change the governance structures for forecasting and project development. Our article shows how planners may help achieve this.