<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class="">How do you tag an emergency spillway? </div><div class=""><br class=""></div>I am tagging a giant flood control reservoir in my region. The “lake” is surrounded by giant man-made embankments on all sides, surrounded by an additional set of embankments, with gates to let the water out. There is no dam per se, because there is ~200 km of this man-made 10-20m tall earthen embankment (levee) around the entire river system - it is part of that. <div class=""><br class=""></div><div class="">When this levee system fails uncontrollably (like it did downstream from me in 2015), it is really bad. <a href="https://www.youtube.com/watch?v=Hfs3OeqiqRk" class="">https://www.youtube.com/watch?v=Hfs3OeqiqRk</a> <br class=""><div class=""><br class=""></div><div class="">This reservoir system catches water during a typhoon from a smaller river, then releases it slowly after the peak flooding into the larger river. this reduces the chance of flooding further downstream. </div><div class=""><br class=""></div><div class="">However, it has 2 sets of emergency spillways (each about 1Km long) to let water out of both sets of embankments, so where it “fails" can be controlled. it is 5 m lower than rest of the embankments surrounding the reservoirs. These were recently added. </div><div class=""><br class=""></div><div class="">I made a polygon on one such spillway. <a href="https://www.openstreetmap.org/way/481898093#map=14/36.2115/139.6880" class="">https://www.openstreetmap.org/way/481898093#map=14/36.2115/139.6880</a> . the heart-shaped lake is the reservoir, and most of the surrounding green areas are part of the flood control basin made by the second set of levees. </div><div class=""><br class=""></div><div class="">These *emergency* spillways are considered safety features of most large water control projects - if the human-controlled gates o the normal spillway jam shut, the emergency spillways will keep the dam/embankments from being over-topped in unexpected places. I know these are a major mappable feature of large dams, but they are not mentioned on the Dam wiki page. Maybe I am looking at it wrong. </div><div class=""><br class=""></div><div class="">As these are not a weir, nor a normal path for water to go, I wouldn’t tag them as a weir nor as a object normally associated with a waterway line running through it. </div></div><div class=""><br class=""></div><div class="">is there an existing tag or another name for these features that I don’t know of? How do I tag these emergency spillways (and heck - these huge levee embankments!) correctly? </div><div class=""><br class=""></div><div class="">Javbw</div></body></html>