Hydroelectric projects can be terrific for meeting peak electricity load demands; if they store water in reservoirs, they can release it more-or-less instantly to generate electricity just in time to meet the demand. This is what pumped storage hydroelectric facilities are designed to do from the start, usually pumping water uphill from one reservoir to another to store energy, then letting it flow back down when energy is needed. The only potential significant environmental impact from this operational phase would result from reservoir water-level changes during the cycle. In a non-pumped-storage situation where the reservoir is behind a dam on a river and the peaking strategy with the best economics is to release practically no water until needed for peaking, then to release a lot, there are plenty of potential downstream environmental impacts. Such a strategy is utilized in the mid-Atlantic US by some utilities. In a paper just accepted by the journal Environmental Science & Technology, researchers at the University of North Carolina and Duke University looked at releases at Roanoke Rapids Dam on the Roanoke River and tried to figure out if adding wind to the mix of renewable power would increase or decrease these potential impacts (Kern et al. 2014). Despite earlier suggestions that it would, they decided not, based on the model results that predicted very little increase in the downstream “flashiness” over current operational conditions, even with 25% new wind market penetration….