Built using locally quarried , unmortared blocks of Oneota limestone , the 25-foottall , 220-foot-long structure is one of the last remaining limestone arch dams in existence . As such , it is a contributing structure of the Lanesboro Historic District and is listed on the National Register of Historic Places .
While such recognition is an honor of which the town is justly proud , it added layers of complexity to the task of restoring the Lanesboro Dam to its former glory . Clearly , this would be no ordinary repair job because this dam is a piece of living history .
Modern Construction Methods Not Allowed
There long had been concern about the overall stability of the dam , as more than 150 years of corrosion brought into question the reliability of the steel cramps that held the dam ’ s limestone blocks together . Were the dam to fail , a catastrophic flood was a genuine threat to downtown Lanesboro and to other communities downstream . So significant repairs to stop joint leakage , improve structural stability , and restore the dam ’ s façade were needed . www . AyresAssociates . com 17