Parks Canada's Earth Dam Rehab Project

While the Parks Canada Earth Dam Rehabilitation Project isn't part of the BRREA Small Hydro Project, it is happening in the same vicinity and the two projects may have some effects on each other. Therefore BRREA has established this page to its website to keep its stakeholders informed on the Earth Dam project.

Over the next five years, Parks Canada will invest $2.6 billion to rehabilitate infrastructure assets within national historic sites, national parks, and national marine conservation areas across Canada. This includes $2.6 million for Burritts Rapids Earth Dam Rehabilitation.

Two of the three earth dams in Burritts Rapids maintain the difference in water levels between the Rideau Canal on one side of the island and the Rideau River on the other side. The third earth dam maintains the water level of the marsh near the north-west end of the dam.

These earth dams were built as part of the original Rideau Canal construction in the 1820's and 1830's or subsequent repair and modification projects, and have had only minor maintenance since then. In the words of Parks Canada, the Burritts Rapids Earth Dam Rehabilitation project "is to improve the condition of the dams while maintaining their use as a walking trail for the community. This project will ensure the long term viability and engineering function of the earth dams."


Parks Canada's Plan

In 2015 Parks Canada started an Environmental Assessment of the Burritts Rapids earth dams to, among other things, identify and catalogue any sensitive or endangered plants, animals, birds, fish, etc. in the areas of the earth dams. Any sensitive areas were identified. One of their major findings so far is that there are several endangered butternut trees. The area in the vicinities of these trees was put off-limits for any subsequent work.

In fall and early winter 2015 contractors for Parks Canada did a preliminary engineering assessment and took several core samples in areas of interest. Using the results of these activities, a plan is being developed for rehabilitating the earth dams. The planning is expected to be finished by early spring 2016.

Parks Canada has been in touch with the Burritts Rapids community primarily through the Burritts Rapids Community Association (BRCA). Parks Canada gave a presentation at the BRCA Annual General Meeting on 25 November 2015, and as a result of questions and concerns raised by community members a follow-up meeting was held on 5 January 2016. Parks Canada will be holding the next community meeting in spring 2016 to present and discuss the plan.


Some Problems with Earth Dams

One of the major problems with older earth dams is trees and brush. Trees and brush may be aesthetically pleasing and provide other benefits. However, the growth of woody vegetation on and near earth dams, including the downstream toe area, can lead to serious problems. Sudden uprooting of trees by strong winds can result in the movement of a relatively large amount of embankment material and create large voids in the embankment. This in turn can lower the crest of the dam, reduce the effective width of the dam, lead to instability of the embankment, and facilitate seepage.

Tree root systems can loosen the packed earth of the dams, and the root systems of trees can be a potential hazard by allowing seepage pathways to develop through a dam. Trees eventually die and their roots decay and rot. The root cavity leaves a void within the dam through which water can enter and flow. This can ultimately lead to failure of the dam by piping (internal erosion). In general, a tree's root system may extend to the edge of the tree canopy or tree drip line, and trees near the waterline are more of a problem than trees on the top or middle of the dam.

Brush and woody vegetation prevent the proper visual inspection of the dam surfaces. The observation of sinkholes, slides, animal burrows, seeps, and other irregularities can be obscured by trees and brush. Woody vegetation can also cause excessive shade which in turn can hinder the growth of sturdy, dense grass coverage. These affected areas are more prone to surface erosion.

The challenge at Burritts Rapids may very well be to establish an acceptable balance between the aesthetic and historical value of the trees versus the engineering need to make the earth dams safe and reliable.


Aerial view of the Burritts Rapids Island. The two main earth dams are shown in yellow.

Aerial view of the Burritts Rapids Island. The two main earth dams are shown in yellow.

(Picture courtesy of Parks Canada Agency)


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Information Session about Upcoming Work

Burritts Rapids

Rideau Canal National Historic Site

Through investments in infrastructure, Parks Canada is protecting and preserving our treasured places, while supporting local economies, contributing to growth in the tourism sector, and enhancing the charm and attractiveness of Canada's heritage sites.

As a part of these important investments, Parks Canada has announced several projects in the area of Burritts Rapids Lock 17 - including work to rehabilitate the earth dams, the swing bridge, and the masonry of the lock. Each of these structures have historic and cultural significance for the community of Burritts Rapids and more broadly as part of the Rideau Canal National Historic Site.

The evening of September 22nd, 2016 Parks Canada staff was at the Burritts Rapids Community Centre to talk about the forthcoming work to rehabilitate the earth dams in the area as well as the work this fall to complete major repairs on the historic swing bridge. The project managers for both projects were on hand to discuss the forthcoming work, respond to questions, and accept feedback from the community.

Earth dam repairs

Large portions of the tip-to-tip trail run along the top of 180 year old earth dams that run along the northern shoreline of the canal approaching lock 17. Parks Canada has announced funding to investigate and rehabilitate these earth dams to ensure that they will continue to be reliable public safety assets for generations to come. Investigations began in late 2015 and Parks Canada is now in a position to provide an update to the community following up on presentations in January 2016 and November 2015.

Swing Bridge

The Burritts Rapids swing bridge is the oldest structure of its kind crossing the Rideau Canal. Parks Canada has announced funding that will enable needed repairs to the structural steel and masonry abutments as well as the replacement of the timber bridge deck. Additionally, the bridge will be sandblasted and completely repainted. The nature of this work will result in an extended closure of the crossing. This closure could come as early as late fall, however, as important preparatory work remains ongoing, it is not possible to provide a specific date at this time. As more information becomes available, Parks Canada will provide further updates to the community.

For more information visit www.pc.gc.ca/rcNorthGrenville

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