Foundation
stress due to soil settlement has occurred from time to time in a number of
areas in the City. This is because much
of the City of Ottawa is located on sensitive marine clays. The sensitive marine clays were formed at
the end of the last ice age when the glaciers retreated and the area was
flooded by the sea. Leda clay, a
familiar term in this area, is a kind of sensitive marine clay.
In most cases,
the extent of the City’s involvement with foundation stress due to soil
settlement has been limited to circumstances where soils or structural
engineers have determined that city-owned trees may have contributed to the
soil settlement. This soil settlement
may have led to differential settlement of the building and related damages to
the foundation and walls.
In the fall
2001, some homes in the Greenboro area experienced foundation stress, ranging
from cracks in the foundation to cracked interior and exterior walls and soil
settlement of yards. Given the number
of residents who approached the Ward Councillor on this issue, the Councillor
arranged for area residents to meet with staff to discuss the matter. At the meeting held January 8, 2002, the
residents voiced concerns about the impact of city-owned street trees and about
the possibility that the de-watering activities undertaken to develop a new
subdivision northeast from their homes may have contributed to the soil
settlement and foundation stress.
Residents raised
a variety of questions that could not be answered by staff without an in-depth
review. Staff agreed to undertake a
review of relevant facts and respond to the questions raised at the meeting ,
and possibly determine the conditions and the contributing factor(s) resulting
in the foundation stress. As residents
in the neighbouring and older area of South Keys also had concerns, parts of
that area were appended to the review.
At the meeting,
staff also agreed to commission a study regarding the impact of the de-watering
activities in the northeast development.
The report on this specific issue was made available spring 2002 to the
residents who had attended the January 8 meeting. The report (referred to as the Golder Report on Hunt Club
Enclave) confirmed that there was no link between the de-watering activities in
the new development and the soil settlement and foundation stress experienced
in the older built-up area. The
community selected a group of residents to work with the City towards a
resolution of their concerns.
Originally, the
completion date for the review was set for Spring 2002. However, preliminary research by staff
indicated that expertise in the fields of geotechnology and hydrogeology was
required to analyze the technical data located in City records, to undertake
field studies to identify existing conditions, etc., to determine with a degree
of certainty the cause(s) of the soil settlement, and to provide
advice/solutions, short and long term.
In addition and given the number of occurrences of foundation stress in
the area, the level of expertise was considered essential to enable the City,
§
to confirm whether existing practices
and development parameters were adequate to ensure the developers and builders
were exercising best practices in developing lands located on marine clays,
§
to confirm or establish improved
practices and development parameters for application city-wide,
§
to protect as much as possible the
urban forest, and
§
to identify remedial strategies and
actions to be undertaken by the area residents and the City.
In order to
ensure impartiality, a firm that had not undertaken any previous technical
reviews for the City or the developers/builders in the area was sought and
retained. Accordingly, the firm
Sarafinchin Consulting Engineers (SCE) was retained in April 2002 to undertake
this technical review and analysis.
The completion
date for the study was rescheduled originally for fall 2002, then extended to
spring 2003. The extensions were
necessary in order to accommodate the capture, compilation and analysis of
seasonal conditions affecting the soils and the water table in the area. Unfortunately, the unseasonably dry
conditions in 2002 prevented SCE from compiling water table fluctuations, and
thus the study was delayed until late fall 2002.
Pending
completion of the review and the technical study, a number of interim measures
were pursued by the City to address the concerns of the residents:
· In 2002,the Transportation,
Utilities and Public Works Department (TUPW) Forestry Services unit initiated a
tree cycle pruning program on the city-owned street trees in the Greenboro/South
Keys area. A total of 700 trees have
been trimmed to date.
· Forestry Services undertook 55 Trees and Foundation investigations
since August 2001, which resulted in the removal of 116 trees.
· Surface Operations placed a
temporary ban on new tree planting through the City's Trees in Trust and
Park Tree planting programs. Forestry
Services has placed 15 trees on hold until this issue is finalized and this has
been explained to the area residents who have wished to subscribe to these city
programs. This figure includes 3 tree
replacement requests from area residents who have lost trees through the
foundation assessment process.
· An information package was distributed by hand to a number of
residents on streets where occurrences of foundation stress had been
identified. The information package,
made available in both official languages (the English version is attached as Attachment
1), was designed to inform residents of the conditions, the purpose of the
review, and the consultant’s work. It
included precautionary steps to safeguard their properties, particularly during
a hot dry summer and information on the care of trees.
· Meetings with the street representatives and the residents were held
to keep them apprised of the progress and share the preliminary findings.
·
A number of boreholes and monitoring
wells designed to gauge the soil moisture content of the soils in the Greenboro
and South Keys area were installed and readings compiled and analyzed. These will remain in place in order to
provide for longer term monitoring.
· As a result of claims that city-owned trees were the primary cause
of soil settlement, the former City of Ottawa had established a program for
undertaking an evaluation to determine whether city-owned trees were a
contributing factor in soil settlement causing foundation damages. As a prerequisite to engaging city
resources, the property owner was required to initiate the review by submitting
a soils report confirming the presence of sensitive marine clays, at their
cost. As a number of residents in the
Greenboro/South Keys area had established the presence of sensitive marine
clays, and in view of the corporate knowledge that most of the area is located
on a deposit of marine clay, the requirement to provide a soils report in order
to initiate the City’s Trees and Foundations investigations program was waived
for this area only. Residents who had
already incurred the cost of the report were advised that they would be
refunded the cost of the soils reports confirming the presence of sensitive
marine clays on the affected property.
The requirement to fund and produce a soils report confirming the
presence of sensitive marine clays remains in place for the remainder of the
City.
·
All the sewers (storm and sanitary)
were inspected by CCTV and where minor cracking was identified, repairs were
undertaken fall 2002 and early 2003.
·
Development records and building
permit files were located and reviewed to confirm whether the buildings had
been constructed in accordance to the Building Code, and to locate soils
reports as required by the development agreements.
A meeting with
the residents was held December 3, 2002 to inform the residents of the
preliminary investigative findings compiled of SCE to date and to advise of the
next steps to be taken. The residents
were advised that the technical report would be completed spring 2003 and that
following consultation with senior management and City Council, staff would
report on the findings to the residents.
Residents were also advised that claims would be considered once the
review and report were finalized.
The review is now complete and staff is preparing a report of
findings to be released to the residents.
Although the report has focused on one area of the City, that of
Greenboro and South Keys, it is expected that the findings will provide
additional knowledge to the City from a city-wide perspective on the impact of
the identified contributing factors and impacts on sensitive marine clays.
DISCUSSION OR ANALYSIS
Given the City’s
soil composition, it is likely that the Greenboro/South Keys experience is not
unique in Ottawa. The area is
experiencing soil settlement and foundation stress primarily as a result of the
combination of factors such as the age of the community, the maturity of tree
canopy and climate change. This
phenomenon may occur in other areas of the City where the same factors (age of
the community, the maturity of trees and hotter and dryer weather) combine to
culminate 20 years or so after the majority of the development has taken
place.
The SCE study
commissioned by the City confirmed the Greenboro and South Keys area is located
primarily on sensitive marine clays, silt and organic deposits left behind
following the retreat of first, the ice age glacier(s), then the Champlain
Sea. The soil composition in this area
varies in type, depth, strength and thickness, etc. Thus, it is feasible that while one residence with mature tree(s)
was free of all signs of soil settlement, the adjacent property could exhibit
significant foundation stress. Further
soil settlements can occur in the study area.
It is estimated that if no remediation action is taken, these
settlements will continue during the next 20 years.
Sensitive marine
clays present challenges to builders in that additional precautions must be
taken to build footings and foundations in these soils. Where such soils are present, the Ontario
Building Code requires that footings and foundations be engineered. The study confirmed that the buildings were
built in accordance with these Building Code provisions in place at the time of
construction
The study
confirmed that the Greenboro Design Guidelines, which set out all the design
details, including the tree species and numbers, as approved by the former City
of Ottawa Council, were adhered to by the developer/builders.
The study
determined the moisture in the soil and the water table underneath the footings
of the affected buildings had been “drawn down” beyond the expected ranges due
to a number of factors, and as a consequence, the soils shrank due to this loss
of soils moisture. Once these soils
shrink, they cannot be “revived”. As
the soils supporting buildings shrank at different rates and locations, house
foundations were subjected to stress not contemplated at the design stage. Differential settlement resulting in the
vertical movement of parts of buildings at different rates can cause cracked
foundations and walls.
The contributing factors identified by SCE were:
·
Climate change
·
Urbanization of the area
·
Vegetation
·
Unanticipated and non-uniform
foundation loads
Each of these factors and their impact on the soils in
Greenboro/South Keys are as follows:
Climate Change:
A key factor, climate change, possibly caused
by global warming, had not been contemplated at the outset of the study. However, review of the last 40 years’ worth
of climatic conditions in Ottawa has revealed that 1991, 1997, 2001 and perhaps
2002 have been some of the hottest and driest years experienced by the City of
Ottawa. These conditions are considered
as the major contributor for the significant water deficit in the ground.
Urbanization of the area:
SCE has confirmed that since the early 70’s,
approximately 50% of the lands in Greenboro and South Keys have been converted
to hard impervious surfaces. Hard
surfaces includes roofs, driveways, roads, pathways, in-ground pools, etc. The design guidelines for subdivisions
promotes the shedding of surface waters via the installation of storm sewers,
hard surfaces such as roads, etc. Residents
have come to expect that streets will have storm sewers rather than storm
ditches at the front of the property, that water will not pond in their yards,
etc. Front yards and driveways are
graded to promote the evacuation of water asap. Precipitation and snow melt are evacuated efficiently and
effectively through the use of hard surfaces and storm sewers. This process has necessarily reduced the
amount of water in the soil.
Vegetation:
The review has confirmed that the maturing trees have contributed to
the soil settlement and foundation stress.
Further, it would appear that the mass plantings contributed
significantly to the damage to some buildings in close proximity. Although the trees were low and/or medium
demand trees as per the Greenboro Design Guidelines, the combination resulted
in more water being retrieved from the soils than what was being introduced
through surface drainage.
SCE surmises that consistently over the last 10 years, more water
has been evaporating from the leaves of mature trees in the area than what has
been introduced by rainfall or snow melts.
Unanticipated and non-uniform foundation loads:
Water in the clay soils counter the loads and associated pressures
on the soils supporting the footings and foundation. Water adds buoyancy to the soil supporting the building load by
filling the small void between the soil particles. Clays can have up to 70% moisture content in their structure, so
moisture loss can bring about volume change.
The design of the buildings appears to assume a continued presence of
water and buoyancy. Thus the loss of
the soil moisture and drop of the water table resulted in increased pressure
and settlement of the supporting soil beyond that anticipated by the designs.
As well, the predominant feature of the homes in Greenboro is that
of an attached garage at the front of the structure with heavy, brick
cladding. These features may have
contributed to the non-uniform loading of the foundation soils.
Recommendation 1
Short term
actions:
1)
Report and meeting with the residents
The Task Group is committed to prepare and
release a detailed report of the findings (including the findings of SCE) and
responses to the questions raised at the January 8, 2002 meeting.
This report along with an executive summary in both official
languages will be finalized and distributed to the residents at a meeting to be
held by the end of July or early August 2003.
It is expected that there will be a high demand for the report and thus
printing costs will be significant. As
the report will be weighty, only an executive summary will be posted on the
City’s web site for ease of access.
2)
Trees
Forestry Services will continue to react to complaints about
foundation damage in accordance with the approved process, with the exception
that the requirement to provide a soils report establishing the presence of
sensitive marine clays in Greenboro and South Keys has been waived (because the
presence of these clays is well established in both these developments)
No new trees are being planted or replaced in Greenboro until staff
have reviewed in depth SEC’s report and have determined the appropriate
strategies and actions to avert or mitigate future soil settlement and
foundation stress due to trees.
In addition, staff will develop strategies for addressing the
immediate loss of trees in Greenboro and South Keys. The Forestry Advisory Committee will be consulted in the
development of appropriate strategies and actions.
3) Public education
Staff will update and re-issue the flyer to inform residents of the
potential for soil settlement and foundation stress, what steps to take, etc
for distribution city-wide and via the City’s web site. This will be particularly essential if summer
2003 proves to be another hot and dry one.
Surface Operations is also working with Marketing and Communications
Branch to prepare tree-watering advertisements for the newspapers, as the
easiest way to avoid de-watering the soil to a critical level is to replace the
ground and surface water that the tree is using by watering the tree
regularly.
4) Claims
If any ratepayer is of the view that some liability rests with the
municipality on this issue he or she may submit a claim to the Risk Management
Division in the Finance Branch. Each
claim will be independently considered. The City Solicitor will also be
separately advising Committee on this issue.
Recommendation 2
Long term
strategies and plans:
Transportation,
Utilities and Public Works:
§
Develop methodologies for
preserving the urban forest in communities where sensitive marine clays are
present and where foundation stress is possible,
§
Develop strategies to promote the
infiltration of surface runoff to water the trees,
§
Educate the property owners on the
care of trees and the foundations of their homes,
§
Review and revise the list of
permitted trees and shrubs,
§
Develop a protocol with Development
Services for reviewing and commenting on proposed planting schemes of
developments where the existence of sensitive marine clays has been confirmed,
§
Install additional clay dykes where
applicable,
§
Review and revise as appropriate the
sewer design guidelines,
§
Review and revise as appropriate the
water supply design guidelines,
§
Review and revise as appropriate the
construction standards and specifications for infrastructure installations.
Development Services Department:
·
Establish Official Plan policies
pertaining to development in areas identified as having sensitive marine clays,
·
Review and develop new development
parameters. In view of the preliminary
findings compiled late 2002, the Department introduced in the new Official Plan
the wording to enable the establishment of policies, which would exact
additional conditions to development in areas where the soils investigations
have identified the presence of sensitive marine clays. Thus, for future development (once the
Official Plan is legally binding), the City will be able to include in
subdivision and site plan agreements additional requirements that would result
in the development deviating from the norm, for example, of requiring the
installation of one tree per lot, or for installing trees at the back of the
lot rather than in the front yard (given the back yard is sufficiently big),
§
Compile a GIS based map that
identifies the locations of the deposits of sensitive marine clays within the
new boundaries of the City of Ottawa.
This map would be available to staff and the public and would serve as
notice of potential difficulties due to soils conditions if certain steps are
not taken,
§
Develop and establish new
development/design guidelines to maximize the retention of soil moisture and
re-hydration of soils to counter the impact of climate change. These guidelines will appear to be counter
to the objectives of the new Official Plan as strategies may include the
imposition of larger lots and front yards to counter the presence of a tree at
the front of the lot, the de-watering impact of sewer trenches at the front of
the property, etc. Staff will consider the
viability of some or all of the following steps:
Ø
the re-introduction of storm ditches
rather than storm sewers,
Ø
the prohibition of asphalt or concrete
paving for driveways. Driveways would
have to be open grid pavers, which allow water to percolate through,
Ø
installation of swales to maximize
water retention on site or absorbent trenches in the front yards,
Ø
minimize grade changes to slow surface
water runoff,
Ø
use of perforated storm sewers to
recharge ground water,
Ø
preloading the lands prior to
development (5-6 years ahead of development),
Ø
requirement to install clay dikes
within the private services trenches,
§
Explore and/or develop new standards
for the construction of foundations in areas where sensitive marine clays are
confirmed.
§
Meet with the local geotechnical and
structural engineers to review SCE’s findings and to educate and identify new
processes/practices,
§
Develop a protocol for reviewing and
commenting on proposed developments where the existence of sensitive marine
clays has been confirmed,
§
Develop and publish literature to inform
homeowners on the development processes, the respective roles of the City, the
developer/subdivider, the builders, the homeowners, and on the care of their
homes and trees.
Consultant:
§
Continue to undertake the field
studies by monitoring the boreholes and wells to identify the moisture content
of the soils and the water table for development of long term strategies,
§
Review and determine whether the water
table has been impacted by development southwest of South Keys residential area
and Greenboro, and report to staff the findings.
ENVIRONMENTAL
IMPLICATIONS
Climate
change has been identified as a key factor in the increasing incidences of soil
settlement and resulting foundation damage.
Immediate reactions are to remove trees that are considered
problematic. One of the City’s goals in
it’s new Official Plan is to increase the urban forest.
Appropriate
strategies need to be developed to address the loss of trees.
RURAL
IMPLICATIONS
The current problems being experienced with foundation stress and
soil settlement are primarily associated with the urban environment.
Staff in
Transportation, Utilities and Public Works Department and Development Services
Department will implement the recommendations as approved by Council.
Attachment 1
This bulletin, issued by the City of
Ottawa, is intended to respond to citizens’ concerns about soil settlement and
foundation stress occurring in some homes in your area. The bulletin outlines:
·
the steps we are taking to address
this issue
·
the type of activities you can expect
to see in your neighbourhood as a result of these steps
·
what you can do
·
and next steps throughout the summer
and fall of 2002
We have used a Question & Answer format to address your
concerns. If you have other questions,
please call one of the following members of the City’s Task Group formed to
undertake a comprehensive review of the conditions causing the distress.
If
the questions relate to soils and trees, contact:
Dale
Philpotts at 580-2424, ext 25543
If
the questions relate to development and the construction of the homes, contact:
Arlene
Gregoire at 580-2424, ext 41425
If
the questions relate to the current adjacent development contact:
Wade
Clouthier at 580-2424, ext 22179.
We realize that this is a troubling time
for you as you wait to hear the results of this study. Please be assured that
the City is proceeding as quickly as possible.
In the meantime, we sincerely appreciate your patience and co-operation.
What is the mandate of the City of Ottawa’s Task Group?
On January 8, 2002,
residents of certain streets in Greenboro and South Keys were invited to a
meeting to discuss their concerns about damages to their homes.
Many of the questions required an in-depth review and
study. At the request of the Ward
Councillor, a multi-disciplinary group of staff and professionals was assembled
to undertake the in-depth review to respond to questions such as:
·
the
planning approval processes for the Greenboro and the South Keys developments
·
the
building design and construction of the buildings and compliance with the
Ontario Building Code
·
a
determination on whether recent nearby development caused or contributed to the
destabilization of the soil substructure and by extension the foundations of
buildings
·
whether
bus traffic on Tapiola Crescent caused or contributed to the destabilization of
the soil substructure, and by extension the foundations of certain
buildings; and whether the potential
impact had been considered as part of the decision-making process
·
whether
trees and/or other plant materials, sewers or other factors caused or
contributed to the destabilization of the soil substructure and by extension
the foundations of buildings
·
whether
measures are available to minimize the chances of future occurrences.
Tell me what steps the City of Ottawa is taking to investigate
foundation damage to homes in the area.
The City is undertaking an in-depth review
to determine the cause of the problems in Greenboro and parts of South
Keys. There are two stages.
The first stage consists of:
- a thorough document review by city staff (such as locating old
records and development agreements, and geotechnical reports) and field
research (such as conducting sewer inspections, and measuring water levels
and soil moisture at boreholes)
Specifically, staff has examined:
- Records documenting the development history of the Greenboro
area; this will be extended to South Keys this summer
- documents and test results identifying the condition of the
infrastructure such as sewer and watermains since the installation
- 273 development and building permit files
- 2.475km of sewers as part of Closed Circuit TV (camera) sewer
reports
- 262 borehole logs listed in at least 15 geotechnical reports
- 42 years of precipitation data with a number of years of
temperature data to follow
- 80 cases of water main breaks in the South Keys and Greenboro
area
- completed engineering and other studies
Since January 2002, 35 trees have been
removed by the City of Ottawa. Twenty
new boreholes have been drilled.
The second stage consists of a
comprehensive review of the problem areas, the interpretation of all the
information located and data compiled, and provision of advice and
recommendations. The City has retained the consulting firm – Sarafinchin
Consulting Engineers (SCE), to conduct the second phase. SCE is independent in
that the firm has not been involved in any of the development of either
Greenboro or the South Keys area. The firm has extensive expertise in the
fields of geotechnology and hydrogeology, including
expertise in sensitive soils such as leda clays.
Hydrogeological expertise is needed to
provide expert advice/opinion on the water table (ability to recharge, whether
the problem may be at the surface for example) and geotechnical expertise to
advise on the cause or combination of causes of soil destabilization.
What
will the study cover?
SCE will
undertake a comprehensive study and, provide a report to the City in the autumn
of 2002. The consultant will focus on
the overall conditions of the soils, water table, the impact of development,
among other factors.
The consultant will:
·
undertake a review of the problem
areas
·
interpret the data compiled prior to
development, during development and more recently
·
determine the possible cause or causes
·
provide advice and recommendations
What
areas are being studied?
Initially, the review focused on issues
related to Greenboro, however, some residents in the South Keys area requested
that the study area be extended to include parts of South Keys.
Greenboro, for the purpose of the study, is
defined as the area bounded by Albion Road to the west, Hunt Club to the south,
and Conroy Road to the east and Johnston Road to the north. The South Keys
area, for the purpose of the study, is defined as the area bounded by Bank
Street to the west, Hunt Club to the south, and Albion Road to the east and
Johnston Road to the north.
What
kinds of activities will I see between now and the autumn?
Activities will include:
- installation of boreholes on City property to gather additional
data on the water table and soil moisture levels in the area
- sewer inspections to determine if the sewers have been breached
and are affecting drainage patterns of the immediate area
- removal of city-owned trees and stumps
- tree trimming
- measuring elevations of roadways to determine the extent of
movement since the last time a measurement was taken at the time the road
was first asphalted
When
will the consultant’s report be available?
The SCE report will be ready in autumn of
2002. A public meeting will be held at that time to discuss the review and
recommendations.
Will the City undertake an assessment and or
inspection of the damages to my home?
We will continue investigations to
determine if trees situated on municipal property are contributing to
foundation damages, as outlined in the attached Tree and Foundation Damage pamphlet.
A building inspector and/or the Building
Services Branch code engineer may visit your property, with your consent, to
conduct an assessment as part of the overall study or to confirm the structural
integrity of your home if damage is extensive.
This assessment will be based on the requirements outlined in the
Ontario Building Code. Depending upon
the circumstances, the
information may or may not be compiled in
the form of a report or section of the comprehensive report.
If you are concerned about damage or
possible damage to your home, we recommend you retain – at your cost - the
services of an expert, such as a structural and/or soils engineer, to determine
the extent of damage, the probable cause(s) and work required. Each site presents its own set of conditions
and solutions. It is essential that you
assess the damage and take steps to correct problems as soon as possible.
Does the City have a role in monitoring properties that have been
reported as having sustained damage?
SCE may approach owners of some homes to
evaluate situations to supplement the information being collected for the
overall review of community conditions.
There are cracks in my foundation.
What can I do?
Cracks in foundations or floor joists,
separations between the floor and the base boards and doors, and windows that
no longer open or shut properly, can be caused by a number of factors. They include shrinkage, temperature changes
and the amount of moisture in a home, recent renovations, and movement because
of foundation settlement.
Larger movements
are normally the result of foundation settlement. Homes can accommodate a certain amount of movement without
serious structural consequences.
We encourage you to hire a structural
and/or soils consultant if you are concerned or if the following has occurred:
The City will remove any trees that are a
contributing factor to visible damage to house foundations.
We will continue to trim the canopy of all
city-owned trees in the area.
What permits are required for repair work?
A building permit must be obtained for any
structural work undertaken to repair the foundation or other structural element
of the home.
Information on building permits may be
obtained by calling the City’s Call Centre at 580-2400.
I am not experiencing problems with my house. Is there anything I should be doing?
While not all homes may be affected, we
encourage you to:
- review the available information and monitor the condition of
your home. The attached pamphlet, Tree
and Foundation Damage, contains some helpful tips on maintenance
- perform regular maintenance (such as painting the windows and
sills, inside and out, re-caulking to maintain the water tight surfaces,
removing debris from the eave troughs, directing the down spout away from
the foundation (but not onto your neighbour’s property), replacing damaged
siding and roof shingles, etc.)
- For more information on maintaining your home, visit your local
library and/or the following web site: www.cmhc.ca
The CMHC Guide to Trees and Foundations in Clay
How do
I care for trees?
Here are some recommendations on caring for
trees on your property and on city property in front of your home.
Newly Planted Trees
A 50 mm (2”) diameter tree needs an
absolute minimum of 40 litres (10 gallons) of water per week. This is approximately the amount held by two
kitchen sinks. The best way to ensure
that all the water applied to the tree actually stays there is to maintain the
earth ring or saucer that was placed when your tree was planted. If you are able to water using a soaker hose
or slow drip, give the tree a minimum of one hour’s worth of water, or better
yet, overnight. During a week when we
receive two or more days of rain, watering is not necessary.
Mature Trees
A tree that has been planted 15 or more
years ago may appear able to fend for itself under any conditions and this is
usually true. By that point in a tree’s
development, its root system has grown into a large volume of soil and can reach
water and nutrients even when surface conditions appear very dry. There is however, a critical point during a
drought when the remaining soil moisture is so tightly held to soil particles
that roots cannot use it. Trees of all
ages suffer when extended drought conditions are experienced. Just like humans, stress can make an
otherwise healthy individual more susceptible to pathogens looking for
weakness. Extra water to all trees
during a drought, regardless of age, can keep defenses strong against invading
insects or disease. Let the garden hose
run at a trickle for several hours or overnight, if possible.
This type of water stress happens very
quickly for trees planted in hard surface sites like those in sidewalks or
patios, or in places where water is naturally shed, like a raised lawn with
retaining walls. Trees in these places
should be helped with a good soaking twice a week throughout the hottest part
of every summer.
Trees Near Foundations
During very dry weather, soil particles
will “lock up” water molecules at a certain threshold level. This is especially true of clay soils whose
particles have very strong electrical charges that hold water very
tightly. This is the start of a battle
where roots try to take up water but are opposed by greater forces from the
soil particles to hold it. Clay soils
will actually shrink in volume because of the water loss, sometimes causing
foundation damage because of the change of structural support from the adjacent
soil. If the deficit is water, this problem
can be avoided by ensuring that trees close to foundations are always well
irrigated.
Again, the overnight trickle from a garden
hose will help maintain water balance necessary to keep a clay-based soil
stable. This should happen on a
twice-weekly basis for as long as drought conditions persist.
Why is
the City pruning trees in my neighbourhood?
Pruning trees reduces the tree’s canopy and
water demand.
Why is the City removing the tree in front of my home when I don’t have
any damage?
The city-owned tree located on the
municipal boulevard in front of your home has been identified as contributing
to the damage to your neighbour’s foundation. This is necessary so that he/she
can make repairs.
Will
the City repair my lawn after the tree is removed?
We will remove the tree stump by grinding
it to approximately 15 cms below ground level. We will level the area and
over-seed it.
Can I
obtain a tree to replace the one removed by the City?
The City will not plant a replacement tree
on city property abutting your property. You can have a tree planted on your
property by the City provided that you enter into an agreement and release
registered on title to your land that makes you responsible for it.
What if
there is a drought this summer?
If there is a drought alert, the City of
Ottawa will issue specific instructions to area residents. This information will be published in the City
Page, which appears on Fridays in daily newspapers.
How
does the Ontario Building Code relate to my home?
The Ontario Building Code sets minimum
standards in the construction of buildings to promote public safety, fire
protection and structural sufficiency in buildings. While the Building Code provides for a set of minimum standards,
it does not deal with workmanship (unless it undermines the standards set by
the Code), nor does it cover many design features marketed by builders. The purchase and sale agreement between the
purchaser and the builder and the New Home Warranty Program are meant to cover
workmanship and other deficiencies.
Many homes in the area were built primarily
before the introduction of the Ontario Building Code, which became law in
Ontario in 1976. Prior to 1976, minimum
building standards were imposed in accordance with the municipality’s Building
By-law. That by-law was based on parts of the National Building Code and the
CMHC Residential Housing Standards for residential construction.
How do I access to the building permit file?
Requests to
view and/or obtain copies of residential building permit records should be
addressed to:
Building Services Branch
Development Services Department
City of Ottawa
101 Centrepointe Drive
Nepean, ON K2G 5K7
ATT:
Mail code 04-11
An
administration charge of $25.00 must accompany requests from homeowners, $50.00
from non-homeowners. Fees for copies of
the plans and/or reports apply also.
What is
the procedure for claims?
Claims will not be reviewed by the City of
Ottawa until after the comprehensive study is completed and the recommendations
are presented. Each claim will be
considered individually. Questions
about claims should be addressed to:
Maureen Graham, Administrator, Claims
City of Ottawa
1595 Telesat Dr.
Gloucester, ON
580-2424, ext. 43093
