It is impossible to try to judge whether the TGD project will have net costs or
benefits. All major water projects have complicated combinations of both costs and
benefits that vary over a project’s lifetime and are difficult to evaluate and quantify in a
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consistent, comparable way. As is typical with such large water projects, the benefits are
typically far easier to identify and quantify than the costs, which often only manifest
themselves over many years, in complex ways. Calculating actual costs and benefits
accurately may never be possible because of the difficulty of putting monetary values
on many of the complex environmental, social, and cultural impacts of the project
(Tan and Yao 2006). Nevertheless, enough time has gone by, and enough information is
available, to begin the process of evaluating the overall implications of the project