Fig. 1.

Sample riffles (filled circles) upstream and downstream of the previous 5th Avenue dam, Columbus, Ohio. Five riffles developed since dam removal (i.e., riffles 2 through 6). Riffle 1 was immediately downstream of an existing lowhead dam of similar size and age to the removed 5th Avenue dam and was sufficiently far upstream of the previous 5th Avenue dam to be considered non-impounded (free-flowing) (Stantec 2010). Thus, this riffle served as our reference reach. Riffles 2 and 3 were located in an actively restored section of the river following dam removal (i.e., natural channel design). Riffle 7 also existed before dam removal