Why is the community of Lehigh at such high risk?

The height of ground in Lehigh above the normal river level is much lower than in other areas of Drumheller, and flood waters are deep (1.1 to 1.7m during the design flood). 

What other measures were considered for Flood Mitigation in Lehigh?

Because the impact of a buyout is so significant for Lehigh, a range of both structural and non-structural flood mitigation measures were examined for the community. The structural measures examined include conveyance improvement, a permanent berm, temporary berms or barriers, and raising residences. The non-structural measures examined include buyouts and status quo.

Why can’t we widen or straighten the river to protect Lehigh?

Widening or straightening the river does not reduce the flood depth at Lehigh by very much (~ 10cm), and it is not permitted by the regulators. The cost of straightening is significant.

Why is a permanent berm not feasible for the community of Lehigh?

A berm at Lehigh would be significantly more leaky than the berms proposed for other areas of Drumheller, due to the permeable soils at Lehigh.  A berm also costs more to build than the value of the properties protected and therefore funding is not available for this measure.

Why are temporary berms or barriers not feasible for the community of Lehigh?

Like a permanent berm, temporary berms would also be leaky.  Based on the volume of dirt required to protect Lehigh, there is unlikely to be time to build a temporary berm between notification of the flood and the peak flow arrival.

Why is raising residences not feasible for the community of Lehigh?

Protecting the main floor of homes is not the only consideration.  Even when houses are raised, public safety is at risk and property can still be damaged.  Access and egress is cut off by flood waters, and emergency response is problematic. No funding is currently available for this measure.

Why can’t Lehigh residents just stay and take their chances?

We understand that buyouts is not the ideal solution for Lehigh residents; however, the level of risk to Lehigh residents and their property is not acceptable to the Town nor to the Province of Alberta. Residents remaining in Lehigh is not an option as they will be putting themselves and others (emergency services) at risk. Funding is available now to remove the risk, so the Flood Mitigation Program is undertaking buyouts.

Why is buyouts the selected mitigation for the community of Lehigh?

Buyouts eliminates the risk of flood impacts to the people and property of Lehigh. The other measures examined were deemed to not be feasible. Provincial funding is currently available for buyouts.

Why is buyouts the selected mitigation for the community of Lehigh?

Buyouts eliminates the risk of flood impacts to the people and property of Lehigh. The other measures examined were deemed to not be feasible. Provincial funding is currently available for buyouts.

Why were other Dikes in Drumheller made a priority over Lehigh?

The Drumheller Flood Mitigation program is a large, multi-year, multi-million-dollar program.  Project delivery for the program needs to be spread out over the coming years.  Work has been prioritized based on how many people each berm protects and how quickly the work could be implemented – Downtown Dike, for example, protects dozens of residents, businesses and community buildings used by residents every day. That being said, the study for Lehigh was advanced early in the program, starting in the summer of 2021, and the mitigation measure of buyouts will be implemented in the coming months.

Didn’t the Aquatic Environment Assessment for Lehigh show that a berm would have minimal impact on the aquatic environment?

It is important to the Town to protect people, the environment and property.  The aquatic and terrestrial studies were undertaken for the project areas to provide a better understanding of potential impacts.  For the range of mitigation measures examined at Lehigh, the channel conveyance measures were discounted on the basis of significant aquatic habitat impact without an adequate reduction in water level.  Other mitigation measures like the berm were understood to have minimal aquatic impact but were deemed to be inappropriate on the basis of groundwater seeping to above ground levels and the high cost compared to the assets protected.

If the berms in other areas are not being designed to prevent groundwater seepage, why is groundwater such an issue in Lehigh?

The soils in Lehigh are different from other areas of Drumheller. They are very porous and groundwater travels quickly through the soils.  During a flood event, the groundwater will seep under a berm and appear above the ground surface, having the potential to cause impacts to properties.

Scott Land and Lease have been hired by the Flood Mitigation Office for land appraisals and buyouts. Is it true that they’re mandated to purchase Lehigh properties for the least amount of money possible?

Scott Land and Lease’s mandate is to comply with the terms of the Provincial Grant Funding Agreement and the Town’s Land Acquisition Policy in negotiation land purchases.  There is no other mandate around the purchase price of properties needed to implement the flood mitigation program.  Appraisals will be completed by an independent third-party appraisal company, coordinated by Scott Land on behalf of the Flood Office.

Why is the Town not covering any extra costs that will be incurred by property owners if they don’t go to expropriation?

Past Provincially-funded buyout programs in Alberta (i.e., Calgary, High River, Fort McMurray) have been completed at assessed value for the property.  As we understand the tremendous significance of buyouts for Lehigh residents, the Town has negotiated with the Province to pay appraised value for buyout properties, which has been found to be well above the assessed value for Lehigh.

Under an expropriation situation, the property value will be determined by a third party, along with the value of damages.

Would removal of the spurs/groynes adjacent to Hwy 10 reduce flood levels?

No, upstream water levels are not expected to be affected by the spurs during a flood event. Alberta Transportation constructed these in 1992 to protect the highway embankment. The  design drawings for the spurs indicate that the right (south) bank was excavated back to maintain channel capacity. These structures appear to have functioned as designed, stabilizing the river bank and promoting bed scour near the tips of each structure.

Has the operation of Dickson Dam during flood events worsened flooding in Drumheller?

No, The Dickson Dam provides a significant level of flood protection to the Town of Drumheller. The Red Deer River 100-year design flood flow rate was reduced from 2,260 m3/s to the regulated discharge of 1,850 m3/s, by taking into account the operation of Dickson Dam.

Has the construction of Dickson Dam resulted in sediment deposition, resulting in a narrower/shallower channel which has worsened flooding in Drumheller?

No, based on a comparison of the 1984 and 2018 river bed elevation profile surveys, there has been no significant change along the Drumheller reach, and some general lowering of the river bed profile was actually noted in the area of Lehigh. Channel width has tended to decrease slightly through Drumheller since 1950, largely as a result of lateral deposition and vegetation encroachment along the river. Conditions at Lehigh were observed to be consistent with trends elsewhere in the valley.

With all the information provided, if Lehigh residents still want to remain in their homes, can they?

No, buyout will be proceeding to eliminate the risk to people and property in Lehigh as well as remove future risk to emergency responders and liability to the Town.

During the preparation of the study, why is it that Lehigh residents were not contacted for their concerns?

Lehigh residents have been spoken to multiple times over the years about the high flood risk in this area. Since June, our communications team has spoken to individual residents, multiple times, using multiple tools, phone, email, mail, social media etc. Personal on-site meetings have also been held.  The most recent Flood Mitigation Analysis Study for the community of Lehigh was initiated as a result of community input. This was not a part of the original Flood Mitigation Scope; it was added to ensure that every reasonable avenue for flood mitigation had been investigated.

Where/how many boreholes were drilled to characterize ground conditions? How come there were no boreholes drilled on my property?

Three boreholes were drilled for the berm assessment study on public land or Town-owned land. Additionally, we had access to the water well records for two groundwater wells, which also helped us to characterize ground conditions. These boreholes and wells provided broad and sufficient coverage across Lehigh.

When will the Lehigh Comprehensive Flood Mitigation Analysis Study Report be officially completed?

The Lehigh Comprehensive Flood Mitigation Analysis Study Report has been completed and has been posted on the floodreadiness.drumheller.ca website.