In the early years of Cedar Rapids' development, the very namesake of the city caused headaches for residents and officials. Steamboat operations on the Cedar River were also influenced by the rapids because the river dropped fourteen feet through the rapids. The drop also offered potential for great water power, if it could be harnessed.
First efforts to dam the river began in 1842, but the first dam to be successful was constructed in 1870 by Nicholas Brown at the foot of what is B Avenue today. Brown charged users of the dam for the power it provided millers and lumber sawyers. In 1894, Brown's dam was damaged by high water and required significant repair.
Between 1914 and 1918, a dam was constructed about 60 feet downstream from the Brown dam. The new one provided power for the cereal millers who had come to town.
Both dams were removed in 1978 with the building of the dam that is beneath the I-380 bridge.
Attempts to bridge the river resulted in disastrous results. A wooden bridge was built at the foot of Iowa Avenue (First Avenue today) in 1856. It was destroyed by an ice jam in the spring of 1857. A pontoon bridge replaced it in the Summer of 1857, that bridge was destroyed in January, 1858.
None of the buildings or structures associated with this early period of bridge construction survive.
Highwater Rock is a pear-shaped limestone boulder in the eastern half of the river just below the dam and is about the only visible landmark tied to those early days of development. Beginning in the 1840s, Highwater Rock was used to gauge river depths. It helped to determine the weights of ferry loads or to decide whether the water depth was sufficient in spring to take steamboats above the rapids.
Highwater Rock remains visible most of the year unless spring floods obscure its view.
Highwater Rock NRHP Filing Documentation
http://pdfhost.focus.nps.gov/docs/NRHP/Text/64500147.pdf
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