The design team considered a number of flood mitigation measures, including a partial road closure (one-way traffic), and leaving the road fully open but constructing a full-height retaining wall.  The preferred measure (2-block road closure of Riverside Drive) was deemed the best alternative in terms of cost, constructibility, leaving room for the river and limiting fisheries impacts.  

The Downtown Berm Design team and Drumheller Emergency Services have been working together over the past several months to better understand impacts from the Downtown Berm project and the potential impacts from the Riverside Drive Road closure. 

The Traffic Impact Assessment (TIA) found that emergency services travel times will not be negatively impacted.

The Flood Team has heard quite clearly from Fisheries and Oceans Canada and Alberta Environment and Parks that dike encroachment into the river will not be permitted if there is a viable alternate, like the option currently selected.  Placing fill material in a river causes significant harm to the aquatic environment, and takes away from the room for the river to flow, so that option was discounted.

To place the road on top of the dike would require that it be built to a much higher standard in terms of the fill, dike side slopes, roadway geometry, guardrails, etc. to meet roadway standards for vehicle loading, which would significantly increase the cost of the berm, so this option was discounted.

One of the Drumheller Resiliency and Flood Mitigation Program’s goals is to build as much permanent flood mitigation infrastructure as possible in the next three years, while we have funding available, thereby minimizing future emergency response efforts and costs.  Building the full section of the Downtown Berm along Riverside Drive will help to meet this goal.  Unlike the adaptive fill reaches for Newcastle and Midland which would have cut off access to homes fronting on Riverside Ave and North River Drive, respectively if a full berm was built there; the section of roadway being closed to accommodate the construction of the Downtown Berm will not cut off access to any private properties.

The cost of the Traffic Impact Assessment (TIA) being done for the closure of Riverside Drive is estimated at $15,000 - $20,000. This cost would be the same for a one-way closure of Riverside Drive as well.

Many options were considered early on for the dike along Riverside Drive; however, it was narrowed down to the 4 preferred options based on cost, environmental impacts, and regulatory acceptance. The option for designing the roadway on top of the dike is significantly more costly and was not evaluated further as a viable alternative. To give an actual cost for this option would run the Flood Office around $10,000 to investigate and then provide an answer. As this option has been deemed not viable, the Flood Office will not be undertaking this additional study. A few items that drive up the cost for this option are acquiring properties to accommodate the horizontal and vertical curvature design, additional safety requirements such as guardrails and other measures as traffic would now be adjacent to a steep and high drop off to the water. Furthermore, there could be significant additional costs for the highway specification road fill materials and construction. 

Encroachment along 5th Street would require full acquisition of these properties, not just encroachment (as the houses are fairly close to the road), and ultimately that’s more expensive. It would also likely require acquisition of 5 properties, rather than the 3 mentioned. The additional 2 properties that would need to be acquired are 475 3rd Ave and 349 5th Street. To acquire these 5 properties would cost between $750,000 and $1,000,000. Furthermore, it would also result in incurring the cost of fully reconstructing this section of Riverside Drive. Since this portion of Riverside Drive is 300m and the cost of reconstructing 1 km of roadway is approx. $1,500,000, that’s another ~$450,000 in road construction cost.

Unfortunately, we have no funds available for temporary mitigation measures for the Downtown Berm or any of the flood mitigation projects.  Additionally, the footprint area required for temporary flood tubes is nearly the same as for the full height permanent Berm (about 5.8m of space would be required for a 3m dike raise with temporary flood tubes, with room to move needed on either side.  Additionally, flood tubes require indoor warehouse storage over the long term, and specialized training and equipment to deploy so can be costly to maintain, especially given that there is no Provincial or Federal funding for these. 

The area of the baseball diamond is not the area that’s most space-constrained for the dike improvements construction, and thus moving the diamond doesn’t address the pinch point. Moving the baseball diamond would still result in a section of Riverside Dr and 5th Street needing to be closed to allow sufficient space to construct the dike.

A preliminary traffic study was completed. A more comprehensive study is in process which will take into account traffic flow year round throughout the downtown area. Emergency response times will be reviewed in the traffic study

We do need to have a bylaw for closing the road and that requires a public hearing and minister approval. We are not exempt from this process and will be proceeding with the bylaw this spring, prior to construction.

The assessed value of all parcels and buildings protected by the Downtown Berm is $30.6M based on the Town of Drumheller's latest assessment numbers.