In 1870, the construction of a dam at Bolingbroke raised water levels by 15 to18 feet. The new water level made one lake out of four, in addition to several adjoining bodies of water. All the lowlands and back bays were flooded, including Long Bay, Green Bay, Buck Bay, Mill Bay and Mud Bay. This created the much larger and more significant body of water we now know as Bobs Lake. The flooding 135 years ago made Bobs Lake look almost entirely different from its pre-1870s river valley status. The flooding of Bobs Lake did not affect Crow Lake because of its’ much higher elevation at the time.
Shortly after flooding, lowland fields were under water, which was not predicted by government officials because the dam was only supposed to raise the water level 24 inches. The rising water flooded the forests and swamps that surrounded the lakes. The flooded woodlands raised the acidity of the lake which killed many fish and left others with sores. Roads were washed out and many bridges just floated away. In winter, loggers traveled on the ice to cut as many trees as they could before they rotted. For the next 60 to 70 years, many parts of the lake remained choked with decaying trees, high stumps and driftwood. Remnants of some of these trees can still be seen along shorelines in various places.
The decision to flood the lake was made by the government following years of drought in the 1860s in an attempt to create a larger reservoir to supply the Rideau Canal with water during summer. For this reason, the regulation of water levels on Crow and Bobs Lake has been historically established under the control of the Rideau Canal Office. Although in the past the Office often ignored the concerns of lake users, in more recent years, it has increasingly cooperated with the concerns of lake users and the lake associations, including the GB&CLA.
Some of the dramatic effects of the 1870 flooding were:
- Several bodies of water were joined together to produce the present Bobs Lake
- Passage to Crow Lake became less difficult when Bobs Lake rose thirteen feet or more, thereby reducing the difference in elevation.
- Later, Crow Lake levels were lowered when a wooden mill dam was removed by ice and a channel was dug to permit navigation.
- Water navigation was extended over several kilometers
- Low-lying land was flooded which created firm shorelines in many places
- The swampy vegetation along many shores disappeared thereby accentuating the white pine and deciduous trees on the higher shores
- The capacity of the lake to support fish and other water-dependent creatures was eventually increased
- After the acidity declined, fish began to thrive and fishing became productive
The long-term effect of flooding was a new Bobs Lake, which became much more attractive to the human eye. It’s new features, such as the great expanse of navigable water; hard-rock shorelines covered with white pine and good fishing, became major reasons for an increase in recreational use of the lake and led to the beginning of tourism.