![\"hydropeaking_diagram\"](\"https:\/\/www.fondriest.com\/news\/wp-content\/uploads\/2015\/04\/hydropeaking_diagram.jpg\")
<\/p>\nHydroelectric dams are often touted as a fairly clean, versatile source of power. While coal-fired power plants must maintain a constant output rate, hydroelectric dams can provide power as it\u2019s needed through a process known as hydropeaking, in which water is released during periods of peak power draw to meet demand. <\/p>\n
Despite the practice\u2019s widespread application, the effects of hydropeaking on local environments hadn\u2019t been thoroughly examined \u2014 that is, until two University of Massachusetts Amherst researchers conducted a study revealing some unforeseen tradeoffs. Published in the journal Hydrological Processes, the paper detailing the study\u2019s findings says that 10 percent of water released during hydropeaking is permanently lost. <\/p>\n
Brian Yellen, a UMass doctoral candidate who earned his master\u2019s through the study, has observed hydropeaking in action from a young age. <\/p>\n
\u201cI grew up fishing,\u201d Yellen said. \u201cMy dad would always warn me: When you\u2019re fishing in the river, make sure you watch a rock or something that\u2019s only three or four inches above the surface. If you notice that it\u2019s all of a sudden below the surface, get out of the river.\u201d<\/p>\n
Downstream of a dam, hydropeaking essentially creates conditions similar to natural flooding, during which water levels can fluctuate by several feet. While this can create a temporary hazard to unwary waders and anglers, the influx is soon absorbed into the groundwater system through a process called bank storage. <\/p>\n
\u201cIt happens during normal floods, and it allows water levels to attenuate somewhat,\u201d Yellen said. \u201cOn hydropeaking rivers, instead of happening every now and then during natural floods, it happens every day during dam releases.\u201d <\/p>\n
The study, which Yellen conducted alongside his advisor and UMass assistant professor David Boutt, aimed to quantify the inputs and outputs of water at different points in the Deerfield River following hydropeaking release. Previous studies had only examined singular points in a river; Yellen and Boutt tackled a 13-mile stretch of theirs. <\/p>\n
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Yellen called the study a work of \u201caccounting,\u201d as each day was spent making fine-scale measurements of water entering the river from its tributaries and exiting through the sediment. The duo spent plenty of time inserting probes a few feet below the riverbed to see how sediment permeability affected the rate of bank storage. Quantifying size, duration and water lost for every dam release \u2014 each of which lasted between seven and 10 hours \u2014 the researchers quickly accrued a large data set. <\/p>\n
Although all that careful bookkeeping offered answers to some of the researchers\u2019 questions, it also revealed something totally unexpected, Yellen said: Up to 10 percent of water released during hydropeaking seemed to vanish. Unable to find the missing water in the river or groundwater, the researchers developed a hypothesis that they feel explains the strange phenomenon. <\/p>\n
\u201cOn days with warmer weather, the trees are actually sucking water out of the banks,\u201d Yellen said. The steady pattern of dam releases raises the water table enough that the roots of nearby trees gain access to it. While the trees eagerly sip from the excess reserves, downstream municipal infrastructure, agricultural operations and riverine biota are denied a significant portion of their daily water. <\/p>\n
The limited scope of the study prevented the researchers from exploring the direct effects of hydropeaking on these users, but Yellen says \u201cthere\u2019s no doubt that there\u2019s going to be impacts.\u201d Furthermore, Yellen noted that the study should be understood as an examination of hydropeaking in a particular region. <\/p>\n
\u201cWe only studied this on a 13-mile stretch of river,\u201d Yellen said. \u201cThe bottom line is that the losses could be even greater than what we document.\u201d <\/p>\n
Yellen isn\u2019t suggesting that hydroelectric dams cease hydropeaking \u2014 the practice is partly what makes hydropower so efficient. But the study does indicate that there are additional tradeoffs to consider when employing hydropower, and more research should be conducted to determine the extent of those tradeoffs. <\/p>\n
\u201cThe question remains,\u201d Yellen said. \u201cDoes this process operate across all environments across the United States, or does it only occur in the Northeast?\u201d <\/p>\n
Top image:\u00a0Brian Yellen records measurements during a hydropeaking event in the Deerfield River. (Credit: University of Massachusetts Amherst)<\/span><\/em><\/p>\n","protected":false},"excerpt":{"rendered":" A practice known as hydropeaking helps hydroelectric dams produce energy more efficiently, but a new study reveals significant unforeseen water losses<\/p>\n","protected":false},"author":18,"featured_media":21680,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5,49],"tags":[60,348,225,183],"class_list":["post-21686","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-featured-articles","category-rivers-streams","tag-featured","tag-rivers-streams","tag-umass","tag-water-level"],"remote_post_permalink":false,"remote_post_featured_image":false,"yoast_head":"\n