LADYSMITH – The Town of Ladysmith is set to begin decommissioning the abandoned Mackie Dam on September 4. The project is expected to be completed by mid to late October.
During this period, a 1.5-kilometre section of the North Loop of the Holland Creek/Heart Lake Trail will be closed to the public. A detour has been established along Colonia Drive, Malone Road, and 6th Avenue to accommodate trail users.
The project is being funded with a $2.75 million grant that the Town received from the provincial government to remediate three weirs along Holland Creek, including the Mackie Dam. The decommissioning of Mackie Dam is expected to cost an estimated $600,000, with the work being conducted by Spider Mountain Excavators (SME).
The decision to remove the Mackie Dam stems from the 2023 recommendation from BC Dam Safety that determined decommissioning was the best option from a safety perspective.
The Mackie Dam, also referred to as the Mackie Road Dam, is a 3.8-metre-high and 12-metre-wide abandoned timber crib structure dam located on Holland Creek near the intersection of the Holland Creek Trail and Mackie Trail.
The Town believes the dam was built more than 70 years ago by the Wellington Collieries Company for coal mining.
At some point over the past 70 years, although it isn’t exactly clear when, the Town of Ladysmith became the dam’s owner through ownership of the surrounding land.
Why is the Town decommissioning the dam now?
Dam Safety BC requested that the Town of Ladysmith undertake a review of the dam with a professional engineer. The review was completed in the fall of 2023 and found that the dam does not meet current safety standards, and that downstream hazard exists. The dam was also found to be a fish barrier.
What does the decommissioning process look like?
The removal of Mackie Dam will consist of mechanical removal of the impounded sediment, the transport of sediment offsite, removal of the dam structure itself, and restoration of the area.
Spider Mountain Excavators (SME) will first create a barrier on the south side of Holland Creek to direct the water flow to the north side of the creek, which will help keep the work area dry. Once work is finished on the south side, the barrier will be moved to the north side and SME will continue with the excavation and dam removal.
A spider excavator, which will handle all instream works including the diversion installation, excavation, demolition of the dam concrete structure and removal of dam timber structures, as well as a long-reach excavator and an articulated dumper will be used to complete the work. A small number of trees are required to be removed during the decommissioning. All removed trees will be offered to Stz’uminus First Nation.
What impact will there be to the trail network?
A 1.5-kilometre section of the North Loop of the Holland Creek Trail/Heart Lake Trail will be closed to the public. A detour route has been established along Colonia Drive, Malone Road and 6th Avenue for trail users. Closures of the south section of the Holland Creek Trail are not anticipated, unless a safety concern is identified.
Is there a risk to any infrastructure during the removal process?
There is little if any infrastructure at risk from decommissioning Mackie Dam. There is an important waterline, which will be clearly identified and protected during the removal process. The decommissioning of the dam will not permanently impact recreation facilities, businesses, or property value.
What happens once the dam is removed?
Upon removal of the dam structure and sediment, remediation of the creek bed will be performed. The contractor will use natural sediment to blend the existing creek channel with the construction disturbance and plant natural species along the creek banks where possible. There is some bedrock outcropping in the area, which will be left as much in the original condition as possible. Fish barriers will be removed and replaced with deadwood and pools to provide fish habitat.
What about the other abandoned dam on Holland Creek?
There is another abandoned dam upstream of Mackie Dam (Colonia Dam), as well as the Town’s water intake dam even further upstream (Holland Creek Intake). Both dams require work to be compliant with dam safety regulations, although they are a lower priority. Work for these dams will likely be completed in 2025 or 2026. This work will include concrete repairs, stream bed improvements, signage, fencing, and flood erosion protection.
Source: Town of Ladysmith