The State of Knowledge Series presents easy-to-read and comprehensive papers about subjects relevant to Mekong hydropower development. They are meant to be an unbiased appraisal of what we know (and don’t know) about a subject. There are five papers in the series, which draw on both regional and international expertise and experience. The opinions expressed in the SOK series are those of the authors alone, and are not representative of the opinions of the CGIAR, WLE, the CPWF, or any associated partners.