Slope stability management

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View slope setbacks with iMap

Medicine Hat is built around a river valley and there are several coulees and creeks within the city boundary. There are some slopes that are considered unstable. 

Certain land features can indicate problems with slope stability, including tension cracks, localized slumping, slope surface erosion, bank erosion or scour, or shallow or deep seated slope failures. Unstable slopes, as well as slopes that have been repaired, are monitored by City engineering staff on a regular basis.

 


Below are several factors which may lessen the stability of slopes.

Development and other human activities, including:

  Excessive irrigation
  Man-made change in drainage patterns
  Removal of natural vegetation
  Disruption, such as earthmoving, at the toe (bottom) of slope

Natural processes, such as:

  Increased or decreased precipitation
  Loss of natural vegetation (e.g. drought)
  Overland flooding from waterways



If your property is situated near a coulee slope or otherwise on very sloped land, slope management is important to minimize failure. Land owners are responsible for addressing slope stability concerns on their own land and for taking measures to mitigate or eliminate risks to people and land.

There are preventative strategies you can use as a property owner to contribute to the stability of your slope.

icon_PDFSlope management guidelines

 slope_illustration

Know the rules for your lot:

There is a slope setback for development established by the City in order to help prevent human activity from causing or advancing potential slope failures. This means that any development (buildings, ponds, sheds, retaining walls etc.) must not occur past this line, which is too near the top of the bank.

imap_example_slope_thmb

How to use iMap to see slope setbacks in Medicine Hat (click graphic for larger image).

  View slope setbacks with iMap

 

You must adhere to all geotechnical recommendations which apply to your lot. Also, you must not alter or deviate from approved grading or drainage plans.

If you do not know where this slope setback line is on your property, or you have any other questions about slope stability, we can help with suggestions. Ask to speak with an engineering staff member at:

Planning & Development Services
Second floor, City Hall
580 1st Street SE
Medicine Hat, AB  T1A 8E6
Phone 403.529.8374
pbe@medicinehat.ca

 

Plan your landscaping:

Human activities such as landscaping can further destabilize slopes.  TIPS:

  Maintain natural vegetation on the coulee slope itself. The root structures of natural vegetation help to stabilize the earth.

  Before building a retaining wall, check with an engineering staff member at Planning & Development Services (contact info above). 

  Locate yard waste and other material away from the top of bank. This will help to maintain the health of the natural stabilizing vegetation. Better yet, use a compost bin!

icon_PDFSee Backyard Composting - It's Only Natural

  Locate pools, hot tubs, ponds etc. away from the top of bank. 

  Seek professional advice for lot grading, landscaping or construction activities.

 

Be water smart:

Excessive irrigation (infiltration) is a leading cause of slope failure on private properties in Medicine Hat.

  Do not irrigate beyond the setback line. Utilize drought-tolerant landscaping to minimize the amount of watering required.

  In front of the setback line, water your lawn for shorter time periods with more frequent cycles. For example, water for 5 minutes in 3 cycles separated by 30 minutes in between, instead of 1 cycle for 15 minutes. Better yet, try xeriscaping!

icon_PDFSee Seven Steps to Xeriscaping

  Do not direct roof drainage (downspouts) toward the slope. Direct the drainage elsewhere, or capture the runoff and drain it though a pipe to the toe of the slope.

Learn more about roof drainage by visiting Basement Water/Seepage.

 

Keep an eye on it:

  Do regular inspections of your property.

  Make sure that existing retaining walls are in good repair.

  Make sure that existing water sources (ponds, hot tubs, irrigation lines etc.) are free of leaks.

  On the slope, check any trees for tilting or bending, which is a sign of slope slumping.

  Work together with neighbours to help minimize slope instabilities.

 



During 2012-2014, the City of Medicine Hat conducted a study of coulee slopes to determine setback boundary lines for future development that may occur near these slopes.

  View setback boundaries with iMap

If you own a property which has such a development setback boundary on it, there are things you should be aware of:

  The location of the setback line does not have any immediate impact on your property.

  There are no existing safety concerns associated with ownership or occupancy.

  It is important to contact Planning & Development Services before doing any new projects on your property (fence, shed, deck, retaining wall, pond, grading, etc.)

Contact:
Planning & Development Services
Second floor, City Hall
580 1st Street SE
Medicine Hat, AB  T1A 8E6
Phone 403.529.8374
pbe@medicinehat.ca

FAQ: DEVELOPMENT SETBACKS NEAR SLOPES

Why was a Slope Setback Assessment done about development setbacks?

The 2012-2014 study was done to assist property owners, developers and City staff in reviewing development proposals adjacent to slopes, and to address public concern with existing developments along slopes.

 

Can I view the 2014 Slope Setback Assessment report?

The report is available for download below (due to file size, it is divided into sections):

icon_PDFPart 1  (p. 1-120)

icon_PDFPart 2  (p. 121-173)

icon_PDFPart 3  (p. 174-211)

icon_PDFPart 4  (p. 212-269)

icon_PDFPart 5  (p. 270-419)

 

How does the development setback line affect my home or property?

Should an existing development (residential or otherwise) be located between the setback line and the top of the adjacent slope, there is no need for alarm or concern.  The existing development was approved using the proper standards of the day.  Information and technologies that provide a better understanding of development around slopes are periodically updated.  The 2014 development setback line will be used to assist in determining appropriate measures that should be considered when designing new development and evaluating those developments near sloping lands.

 

How does the development setback line affect future development in undeveloped areas?

New developments must be located outside the development setback line unless it can be demonstrated through technical engineering reports to the satisfaction of the Approving Authority that the new development can adequately address slope conditions.

 

Is my home in any danger?

There are no residential homes currently at risk. To enhance the long-term sustainability, property owners should make themselves aware of the local site conditions and consider adopting property management practices for sites near slopes. See How can I prevent instability?, above.

 

Does this mean I cannot do any additional development on my land?

Future and infill development can occur within the setback, if the developer provides the necessary engineering report confirming the site is suitable for the intended development, or provides the necessary engineered controls to ensure the development is safe from future slope movement.  This may include site specific slope assessments and engineering controls such as foundation walls or a deep foundation system.
For questions about future development, contact Planning & Development Services at pbe@medicinehat.ca or phone 403.529.8374.

 

Will this affect the value of my property?

Property values are determined based on a number of factors.  Property owners should discuss concerns about property values with a real estate professional.  Presently, there are no plans for the City to purchase properties affected by development setbacks.

 

Will this affect my property tax assessment?

Property owners may contact the City Assessment department to discuss the assessed value of their property.  The Assessment department estimates the market value of each property annually, following provincial regulations.  In the event there is a slope failure or an owner has an engineering stability report that has a detailed cost estimate to remediate a slope, the report should be presented to the Assessment department.  While a setback line may raise a potential issue, a change to market value will require sales evidence or an engineering report with an estimate of the cost to stabilize the slope.

 

How can I learn more?

The best way to gather more detailed information regarding a property or potential development near a slope is to schedule at meeting with Planning & Development Services.  Contact pbe@medicinehat.ca or phone 403.529.8274.



slope_fail1It is the property owner's responsibility to mitigate or repair slope stability issues and/or damage, whether the issues are the result of natural processes or the actions of the landowner. If a failing slope has created a safety concern, the City may issue orders against the owner to ensure that the property is secured and returned to a safe condition.

If your property is experiencing a slope failure, ask to speak with an engineering staff member at Planning & Development Services (contact info below). The City will investigate slope stability concerns on private property and may offer suggestions. However, the City will not make direct recommendations or design solutions for issues on private land. Land owners should seek the advice of qualified professionals for recommendations or designs.

Contact:

Planning & Development Services
Second floor, City Hall
580 1st Street SE
Medicine Hat, AB  T1A 8E6
Phone 403.529.8374
pbe@medicinehat.ca

 

Property tax/assessment questions:

If a slope has failed or is failing on private property, owners may have questions about their property tax, based on the loss of physical property. Questions related to property taxes should be directed to:

City Assessment
First floor, City Hall
580 1st Street SE
Medicine Hat, AB  T1A 8E6
Phone 403.529.8114
assessment@medicinehat.ca



If a slope on City land is deemed to have a likelihood of failure and will cause damage to City infrastructure (trails, roads, structures, etc.) the slope will be identified for repair. After public safety is ensured, an engineering consultant will likely be hired by The City to investigate the cause of the slope failure and to recommend solutions. Then, measures can be taken to repair and/or mitigate the situation.