Stream Slope as an Indicator for Drowning Potential at Low Head Dams

With the increasing availability of low head dam inventories for United States, next challenge is discovering how to determine what dams pose greatest risk public safety, preferably before a death occurs. Submerged hydraulic jumps create dangerous current that drowns roughly 50 recreationists each year, and high tailwater key element in its formation. Using simplified approach based on Manning equation, flat downstream slopes can be predictor tailwater. Stream at Colorado, Idaho, Indiana, Maryland, New Mexico, North Carolina, Pennsylvania were collected from NHDPlus HR, with recorded fatalities compared stream no fatalities. Mann–Whitney U test, there was not enough evidence reject null hypothesis statistically significant difference between two populations. Until more fatality data are compiled locations verified, individual testing recommended establish respective flow range likely safety.