Knowsley Replacement Unitary Development Plan - Knowsley Council

ENVIRONMENTAL PROTECTION AND NATURE CONSERVATION
ENVIRONMENTAL PROTECTION AND NATURE CONSERVATION
POLICY ENV5:
CONTAMINATED LAND
1. New development will not be permitted if there
is existing contamination on the site which
could, as a result of the proposed development,
place the occupiers or users of the
development, ecological systems, the water
environment or surrounding land uses at
unacceptable risk.
2. Where there is evidence that a site may be
unacceptably affected by contamination,
proposals shall be accompanied by a site
investigation report and schedule of
remedial measures.
3. Where remedial measures are necessary then
a verification report must be submitted before
the development is brought into use to
demonstrate that remedial work has been
satisfactorily completed.
4. Where ongoing monitoring and risk
assessment are necessary, reports must be
submitted to the Council on an agreed basis.
The developer must undertake any further
investigations or remedial measures which the
risk assessment shows to be required.
EXPLANATION ENV5
13.21
Previously developed sites may have been affected by
past land use in such a way that may cause harm to
human health or the environment. Such sites need
to be brought back into beneficial use in line with
the Government’s policy on regeneration of
brownfield sites.
13.22
Historically, the main industries within Knowsley have
included collieries, the extraction of other minerals
(including, gravel, sandstone, marl, clay and pebble
beds), cable manufacture, watch making and
potteries. The deposit of various materials has taken
place within various locations, for example through
the infilling of excavations. Potential sources of
contamination include for example chemical or
biological contamination or contamination from
gas from any source. Issues of stability and
subsidence should also be considered when
proposing development on made or potentially
contaminated ground.
PROCEDURES
13.23
It is the developer’s responsibility to find out the
extent of any harmful substances affecting their sites.
It is important to protect the development site and
other receptors from any contamination. However, the
Council will have regard to sources of information at
its disposal and will provide advice to developers.
13.24
Where there is evidence that a site is potentially
contaminated, the Council will require site
investigations and risk assessments to be carried
out. Details of these, together with any remedial
measures that are considered to be necessary and
their timetable for completion, should be submitted,
normally at the planning application stage, and
agreed with the Council. Where there is evidence that
development of a contaminated site could cause risk
to an existing ecosystem, applicants will also be
required to submit an ecological survey with the
application together with details of how the risk
would be mitigated.
13.25
Planning conditions or legal agreements will be used
to ensure that agreed remedial measures are carried
out to the approved timetable, and that the
satisfactory completion of such measures is verified by
a suitably qualified expert. A verification report,
including evidence to confirm that works have been
satisfactorily completed, must be submitted before
such conditions can be fully discharged. Evidence
should include for example: photographs; on site logs
and records; results of any validation testing; waste
transfer notes; and delivery notes for new materials.
Where monitoring and risk assessment are needed
after the development is complete this must be
reported to the Council according to prior agreement.
The developer is responsible for carrying out any
further remediation works which such risk
assessments indicate are necessary.
13.26
Under Part IIA of The Environmental Protection Act
1990, the Council has prepared a strategy (see
footnote 17 ) which describes how it will inspect its
area for contaminated land, and seek to secure the
remediation of any land which is found to be
contaminated. Developers are advised to have regard
to any liability that they may have under this
legislation when carrying out development proposals.
Failure to remediate sites to a standard compatible
with the part IIA regime may leave a developer liable
for future remedial works.
POLICY LINKS
Policy ENV9
“Protection of Habitats and Designated Sites”
Policy ENV6
"Landfill Gas"
POLICY ENV6:
LANDFILL GAS
1. Development on former landfill sites, or within
250 metres of current or former landfill sites
will only be permitted, where the applicant can
clearly demonstrate that there is no risk from
the generation or migration of landfill gas or
other hazardous substances, or that
satisfactory measures can be taken to counter
any possible hazard either to the development
site or other receptors.
2. Residential development will not be
permitted where active gas control measures
are necessary.
3. Where remedial measures are necessary a
verification report must be submitted before
the development is brought into use to
demonstrate that remedial work has been
satisfactorily completed.
4. Where ongoing monitoring and risk
assessment are necessary, reports must be
submitted to the Council on an agreed basis.
The developer must undertake any further
investigations or remedial measures which the
risk assessment shows to be required.
EXPLANATION ENV6
13.27
The decomposition of material within landfill sites
can cause the generation of landfill gas. This gas can
migrate in any direction through permeable ground,
structures such as drains or even dissolved in water.
Gas can subsequently enter or affect adjacent land or
buildings and pose an unacceptable risk to human
health, property or ecosystems. Without control, the
accumulation of gas may lead to explosions and fire
risk, or to odours and the risk of asphyxiation or toxic
effects. The latter may also affect ecosystems.
13.28
In the event of failure of active gas control measures
an unacceptable risk would be presented to property.
Gas monitors used to back up such systems may also
fail. In the event of such failures there would be a
very high risk of a serious incident. It is therefore the
Council’s policy not to permit residential development
where site conditions are such as to require active
gas control measures. This approach is in line with
guidance (see footnotes 18 and 19 ).
17 ”Contaminated Land Inspection Strategy” Knowsley MBC, June 2001
18 Building Regulations 2000, Approved Document C “Site Preparation and Resistance to Moisture
19 BR212 “Construction of New Building on Gas Contaminated Land” Building Research Establishment
156
KNOWSLEY REPLACEMENT UNITARY DEVELOPMENT PLAN: Adopted June 2006
KNOWSLEY REPLACEMENT UNITARY DEVELOPMENT PLAN: Adopted June 2006
157