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Trail Enhancements to Protect Sensitive Floodplain Ecosystem

Save Our Seine is currently working with the City of Winnipeg to modify the low-lying riparian trails (“monkey trails”) to protect sensitive vegetation. These rustic and natural trails provide an alternative to the paved upland trails. They have been enjoyed by hikers, birders, photographers, and cyclists for decades. These riparian trails are located on the floodplain of the Seine River where the water table is close to the surface of the soil. The trails are used by both pedestrians and cyclists - even when the river level is high and sections of the trail become wet. The trails are improvised and therefore don’t meet all city standards for accessibility and are considered “use at your own risk.”


The use of these trails has increased as the nearby population has grown as a result of the development of Royalwood. Greater demand has led to damage to the riparian vegetation and bank erosion. Heavy use of the trails in general, but especially when the river level is high (and the trails are wet) has resulted in:

  • Soil compaction on trails that parallel to the river bank which interferes with the natural flow of water into the river and results in pooling of water on the compacted soil

  • Exposure of tree roots which is causing damage to many mature trees

  • Large, muddy sections that grow increasingly larger as people trample surrounding vegetation to avoid the muddy trail

  • Make-shift bridges, corduroy, and culverts from pallets and other materials being used to traverse muddy patches and natural creeks

  • Trail braiding as people create new paths to go around the wet spots and trail obstacles

  • Natural creek crossings that are blocked by collapsed culverts, boulders, and other materials

  • Vegetation loss and soil erosion at steep sections where the trails transition from the upper banks down onto the floodplain. The loss of vegetation on these steep banks results in large patches of bare ground that are susceptible to erosion. The exposed soil is easily carried downslope towards the river during heavy rains.


Goal

Save Our Seine is working with the city to conserve and protect this unique and sensitive wetland area. The overall goal in undertaking the current trail enhancement work is not to enhance the trails for cyclists versus pedestrians (or vice versa). It is to protect this sensitive riparian habitat from damage while maintaining the use of these beautiful and natural riverside trails by pedestrians and cyclists.


Save Our Seine (SOS) spearheaded the initiative, obtained funding, and is managing the project. SOS engaged Scatliff+Miller+Murray (SMM) landscape architects to develop design solutions for each type of problem. The project team includes adventure cyclists as well as more passive trail users. The needs of both user groups (cyclists and pedestrians) were given equal consideration throughout the design process. The trails are city property and are within the jurisdiction of the Parks Department. As such, the City of Winnipeg is a key stakeholder.


Project Implementation

Some of the design solutions have caused concern among trail users. SOS wishes to thank everyone who reached out to us so quickly to identify issues as this work was being done. This allowed the project team to address these concerns with the contractor in a timely way. The concerns that were raised in social media have now been addressed by the project team. Please let us know if you think we missed anything. SOS is grateful to everyone who keeps their Eyes on the River and promptly reports when something is amiss.


Trail Issues & Design Solutions

  1. Erosion at Steep Fall Lines/Concrete Step-Downs: The original design solution called for creating new benched trails on an angle to the slope so the steep fall lines could be decommissioned. Site visits determined that this would create too much disturbance to the vegetation and attempts to decommission the steep fall lines would be unlikely to succeed. The use of concrete blocks to create step-downs was explored as an alternative design solution to mitigate the erosion on these very steep sections of trail. SOS was unaware of this change until the first step-downs were installed. Pedestrians were pleased with the step-downs but site inspections determined that the concrete blocks used were too wide and left no room for cyclists to pass by on either side as was reported through social media. As such, the implementation did not meet the project goal. The width of the step-downs was subsequently modified by the contractor so that there would be room for cyclists to bypass the steps. Each of the steep fall lines has now been modified to maintain access for pedestrians and cyclists.

  2. Muddy Sections/Raised Tread: Low muddy sections of trail where the soil has been compacted over time have been cleaned up (makeshift solutions removed) and these sections of trail were raised to a higher level. The addition of new material should prevent water from pooling on the trail and allow trail users to stay on the main trail, thus reducing trail widening and trail braiding. Although this material has been mechanically compacted, some sections of trail will be a bit soft until the new material has had time and the right moisture conditions to fully compact.

  3. Exposed Tree Roots/Root Protection: Exposed tree roots have been covered to prevent further injury to these trees. The roots have not been cut or removed. This should reduce stress, prevent root injury, and prolong the lives of these trees. The project team recognized that these exposed roots were useful markers and were enjoyed by cyclists but felt this was necessary to save these valuable trees. The cooling shade they produce is good for people, wildlife, and the health of the river.

  4. Creek Crossings/Rock-armoured Dips: Makeshift solutions at creek crossings were cleaned up (removal of planks, old pallets, old rusty pipes, etc.) and replaced with rock armoured dips. This is designed to allow ditches or small creeks to cross the trail and enter the river. The rock armouring will prevent the creek from washing out the trail. The trails should remain useable by pedestrians and cyclists except during brief periods when the flow may be very high.


Why Trail Enhancements Were the Preferred Approach

Over the years, many options to protecting sensitive riparian areas have been considered including:

  1. Permanent closure of the lower trails to all trail users. This drastic measure would be best for the ecosystem but unpalatable for trail users who prefer the more natural experience these trail provide compared to the upland trails.

  2. Temporary closure of sections of the lower trails to give the vegetation time to recover. Although less drastic, this would require extensive public education or enforcement to prevent people from ignoring the closures, re-opening trails, or creating new trails.

  3. Building a raised boardwalk to protect the wetland area. It would be extremely expensive to build a boardwalk the full length of the riparian trails. A boardwalk would enhance the pedestrian experience but would diminish the experience for cyclists.

  4. Trail enhancements. Use a more targeted approach to identify specific problem spots (muddy sections, trail widening, trail braiding, exposed roots, bank erosion, etc.) and implement design solutions to protect the vegetation and lessen erosion of steep banks. This approach balances conservation of this unique and sensitive riparian area with the on-going use of the low-lying floodplain trails by both pedestrians and cyclists.


© 2020 Save Our Seine River Environment Incorporated