There are going to be social impacts for New Brunswick regardless of which option NB Power chooses to deal with the deteriorating Mactaquac dam, according to a new report.

Those potential impacts range from changing watershed views and property values, to the psychological trauma of seeing long lost homesteads emerge from the waters of a drained headpond, to a returned risk of ice-jam flooding down river from the dam as far as Fredericton and beyond.

They are all explored in a consultant's report released by NB Power in advance of open houses scheduled about the project in October.

The Crown utility must rebuild, refurbish or remove the deteriorating dam by 2030, at an anticipated cost of between $2 billion and $5 billion, depending on the option chosen.

The report by Dillion Consulting is being put forward as a discussion paper for New Brunswickers to consider as NB Power decides which option it wants to recommend to government.

1. Exposure of land/islands

If the headpond is drained, approximately 5,300 hectares of land will be exposed, including lands of both sides of the headpond and islands that were submerged during its creation.

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Snowshoe Island was covered by the headpond when the Mactaquac dam was created. (Provincial Archives New Brunswick)

"At this time, the future use of these newly exposed lands is undetermined," states the report.

"Opportunities for recreation, conservation, agriculture and development exist.

"The exposure of these lands also raises the potential for the exposure of contaminated sediments. Once identified/characterized, these will be managed in accordance with the regulatory requirements."

NB Power is also studying safety risks associated with slope stability and the submerged infrastructure once the water level would be lowered.

The report says there is "considerable speculation" on what shape the land and infrastructure, which became submerged after the dam was created, is in.

"The potential social effect of exposing these remnants may be significant particularly for those members of the community who are familiar with the area before the dam was installed," the report said.

"For the First Nations, the emergence of traditional lands will be dramatic," states the report, which adds the recovery of the ecosystem to its natural state will take time.

"Elders of the community will remember the ceremonial importance of the area.The psychological effects require further study."

Another question raised is the possible reinstatement of lands to previous landowners or to current adjacent property owners.

2. Flooding due to ice jam events

The construction of the dam has mitigated the effects of ice jams down river from the dam.

However, removing the dam would lead to the possibility of ice jams happening downstream of the dam to Oromocto and beyond.

"There is limited planning and mitigation available should the river be restored to its pre-dam condition," states the report.

"Option 3 would allow the free movement of ice, which could lead to infrastructure damage downstream of the dam. The area most at risk is in the Fredericton area."

3. Intakes and outfalls

If the dam is removed, wastewaster outfalls in Woodstock, Woodstock First Nation, Grays Aqua, Nackawic, AV Nackawic, Woolastook Park, Mactaquac Provincial Park and Centennial Park could become stranded as they would no longer be carrying wastewater to the river.

In addition, the ability of the receiving water to handle wastewater discharges may need to be assessed.

Properties and agricultural operations that take water in from the headpond — including Kings Landing Historical Settlement — could see their intakes stranded.

"The extent of the potential effect will be from Woodstock to Oromocto. It is expected, however, that through engineering design and planning . . . this effect will be appropriately mitigated," the report states.

4. Land acquisition

The report notes that due to the large-scale expropriation that occurred during construction of the dam, further expropriation is "a matter of heightened sensitivity to area residents."

'Efforts should be made to minimize the level of involuntary expropriation.' - Dillon Consultants' draft report

"For some land owners, the sale of their lands may be seen as a positive impact, assuming fair market value or a slight premium is provided for property acquisition.

For others, expropriation could be seen as an incursion on their property rights. Efforts should be made to minimize the level of involuntary expropriation."

Land adjacent to Kingsclear First Nation and the community of Kingsclear will likely be needed to support the project.

Land acquisition will be needed for all three options, with the most land likely required for replacing the dam. The option to remove the dam would require the least amount of land.

5. Municipal water and domestic wells

Several municipalities and residents that used the headpond for water may see negative effects from draining the headpond. Of 692 groundwater well records examined, 60 per cent were within 300 metres of the headpond.

"The drawdown of the headpond could interact with nearby private wells. Shallow wells and those closest to the existing heading will be most at risk," according to the report.

Woodstock and Nackawic both have municipal water supplies connected with the headpond or river.

"Recognizing that the quality and quantity of potable water may be at risk with a drawdown of the headpond, considerable work has been done on understanding the existing resource," the report said.

"These issues will be addressed to identify the appropriate mitigation to minimize the impact of the effect."

6. Nuisance effects during project phase

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NB Power president Gaetan Thomas is faced with choosing to rebuild, refurbish or remove the Mactaquac dam by 2030. (CBC)

Noise, vibration, and dust are all anticipated nuisances resulting from the project, with the effects largely limited to the area around the construction zone.

Odour and dust are anticipated effects from lowering the headpond, should that option be chosen. 

"The length of time over which residents may experience odours is not clear and will vary depending on the rates of drawdown," it said.

The report states the headpond would be drained over a three-year period, to be followed by the demolition of the dam over the fourth year. 

7. Property value

"The potential effects of [removing the dam] on property value cannot be estimated with certainty at this time. It can be assumed, however, that properties with view planes over the water will have an inferred higher value while those properties no longer with apparent direct water access will likely see a reduction in value," the report said.

"This reduction in value will logically be during drawdown and until the shoreline stabilizes and is revegetated."

8. Transportation disruption

Under all three options, access across the river in the Mactaquac area will be maintained with different options currently under consideration. The consultant states the design and construction of the preferred transportation link will be a separate project that will likely be led by the New Brunswick Department of Transportation and Infrastructure, with separate environmental approvals required in advance of the construction and demolition of the dam. High volumes of heavy truck traffic are anticipated, with the two options that would maintain the headpond requiring and estimated 27,500 to 77,500 heavy truck trips through the area over a construction period of seven to 10 years. "Anticipated volumes of heavy truck traffic will have detrimental effects to road integrity, in addition to effects on road congestion, safety and noise."

9. Viewshed changes

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A water view from Kelly Creek the could change if the option is chosen to remove the Mactaquac dam and restore the run of the river. (Dillon Consulting report)

People living from Nackawic to just below the dam would see changes in the view from their property if the headpond is eliminated. "Lands previously inundated will be exposed and many water views that currently exist will be temporarily replaced by headpond bed (sediment/mudflats) that will likely be naturally re-vegetated. It should also be recognized that many headpond views will be replaced by a free flowing river also with considerable aesthetic appeal.

"It is difficult to quantify or describe the magnitude of the impact of the visual landscape under Option 3. There are innumerable view planes around the headpond and scenic quality is subject to individual values and preferences which will vary from one person to the next."

10 Recreational use

If the headpond is drained to restore the river to its natural state, it would limit the area available for motor boating, house boating and yachting. Inlets and basins would no longer be available. During low water conditions, boating activity will be limited to canoeing and kayaking opportunities in some areas. Campgrounds and parks may be affected if direct access to the river is not availalble. Recreational fishing for smallmouth bass and muskie may be negatively affected due to habitat alteration, but over time  that could be offset by an increase in striped bass and Atlantic salmon.

"From a community perspective, many of the effects will be immediate and lasting," states the report. "The length of time for new recreational opportunities to emerge is unknown."

11. Emergency services, infrastructure and housing

An influx of construction workers for any of the options will increase demand for emergency services, hospitals, housing and schools. At this time there are no plans to establish a work camp for the workforce, which could result in a temporary upward pressure on the housing market in the area. Those demands would be greatest for the options to rebuild or refurbish the dam. The third option to remove the dam would require only a peak labour force of 150 people over a three- or four-year timeline.

12. Community identity

Approximately 100,000 people live along the headpond and river between Woodstock and Oromocto. The Town of Nackawic as developed after the headpond was created and should the headpond be drained, it would likely experience the greatest loss of community identity. The consultants anticipate that loss could be offset by the local economy generated by the AV Nackawic mill.

13. Employment and local businesses

Dam construction typically demands large numbers of unskilled and semi-skilled workers and relatively small numbers of skilled workers. All three options will result in substantial expenditures. Negative effects for local business include temporary disruptions from traffic disruptions. Commercial campgrounds, boating companies and private marinas may be threatened if the decision is made to draw down the headpond.