River Valley and Ravine Setbacks – a.k.a “Top of Bank” [UPDATED]

[UPDATE on outcome at end of post.]

The city needs a new policy for dealing with urban development along the edge of the river valley and ravine system. [Background here.] The latest draft came to City Council’s Executive Committee today.

We have about 22km of such edges remaining in the city where development may occur over time, and the policy could come to bear on a redevelopment in an existing area.

Since 1985 we’ve had a very weak policy which called for roadway along the edge with houses only on one side of that road. Because of a litany of ambiguities in the old policy and prior councils’ willingness to grant exceptions, only around 20% of the development that’s occurred since 1985 has a road at the edge. In many areas, especially in the Southwest, the frequent result has been houses backing directly on the ravine and valley, while some more recent cases have trails providing some buffer.

Let me be clear that I support a 100% continuous public access that is wide enough to provide good separation for wildlife, facilitate emergency access, as well as ensure long term geotechnical stability of the lands. I don’t necessarily think that this public access needs to take the form of a roadway; but in certain instances, as outlined in the policy, roadway may be appropriate and a minimum (30% is proposed) should be provided.

For development backing onto the slope, the draft policy proposes a 15m buffer for public access, which seems to have support from most stakeholders. It sounded like the developers can support this separation but are worried about how the lands will be traded against other obligations (for roads and parks mainly) when the land is subdivided into individual lots. This is one of the implementation details that needs more work.

Today at the public hearing some called passionately for a return to the 100% goal of the 1985 policy, and the creation of scenic roadways like Saskatchewan Drive and Victoria Promenade. Incidentally, few realize that those drives are scenic because a lot of the original vegetation was removed over the years to improve the view. Removing vegetation can weaken the slope significantly too.

The other factor that can weaken slope stability is water, either from poor drainage on a lot or from the many illegal backyard sprinkler systems that are installed in homes backing on the valley or ravines. Clearly we need the larger setback to mitigate this, and we’ll need stronger enforcement of infractions, and protection against liability for the city in the event that a property owner’s carelessness causes damage to the slope and others’ property.

It seems we’re close. Council will work on it some more next week and then some further consultations with the 29 identified stakeholder groups and hopefully we’ll be able to approve a robust policy that can ensure safe slopes and continuous public access.

[February 26, 2010 Update: Council approved the revised policy C542 on February 17. It provides for 100% continuous public along the Top of Bank, a minimum of 30% of which shall be either abutting a roadway or abutting park space fronting onto the roadway. It requires a minimum of 10m of setback from the ‘long term line of stability’ (established by geotechnical study) whereupon a trail will provide public access, and where houses back directly onto the trail a 6m wide public access is required every 120 metres. The length and breadth of the policy and background material can be found in the city’s meeting records here. I supported the policy as it met my goal of continuous public access to the river valley and ravine edge.]