HomeMy WebLinkAboutStormwater Management PlanUpdate: June 2013
CITY OF MAPLE RIDGE
STORMWATER MANAGEMENT PLAN – THREE TIER SITE SOURCE CONTROL GUIDELINES
A stormwater / rainwater management plan must be submitted to the District which fulfills the
requirements of the current Watercourse Protection Bylaw. A final stormwater management plan
should be submitted and approved by the District before any construction works commence on site.
The Stormwater plan and report should include the following:
a) Provide a conceptual Stormwater / Rainwater Management Plan for the site early on in the
process with the conceptual development layout that must address the following factors
before a final design layout :
The SMP must consider how it is going to address the District’s three tier stormwater site
source control requirements including DFO standards for stormwater volumes, runoff
rates, and water quality.
The conceptual SMP must consider how it will respect potential conservation setbacks
associated with the protection of significant natural features such as watercourses,
ponds, or wetlands;
Consideration of potential setbacks associated with geotechnical areas, steep slopes
over 15%, tree conservation areas, community greenway trail corridors, etc
Consideration of any new development plans in the neighbourhood that require
integration of resources for dealing with water volumes, velocities, and quality; and
Consideration on site and off site of any groundwater management concerns that may be
impacted by the proposed works, especially in areas within or surrounded by vulnerable
aquifer zones.
Within environmental DP areas, a best level of effort must be demonstrated to limit the
total impervious area for the site where possible meeting the 10% runoff volume target.
b) Before second reading and before any subdivision servicing construction related works
commence on a development site, a final Stormwater / Rainwater Management Plan (SMP)
must be submitted to the District’s Engineering and Environment section for review and
approval. The SMP will need to include the following:
Rationale on how the SMP will adequately address current federal, provincial, and
regional stormwater / rainwater site source control regulations and standards focusing
on three tier site source controls where possible as required in the Watercourse
Protection Bylaw 6410-2006.
Final SMP design drawing that illustrates where the three tier site source controls will be
implemented along with appropriate calculations for any larger detention or bio-filtration
facilities. Site source controls should include consideration of bio-filtration swales &
appropriate sized oil water separation controls along roadways and parking areas. For
dealing with runoff rates and water quality, on-lot topsoil amendments and on-lot
detention facilities will be required where appropriate;
A final letter of assurance from the engineer of record is required that has been signed
and stamped. The letter must provide assurances that the engineer of record is satisfied
that the SMP meets the District’s three tier stormwater requirements & DFO standards
with respect to detention, runoff rates, and water quality.
Update: June 2013
Consider appropriate design & sizing for above ground stormwater management
detention facilities to ensure they mimic natural features where possible, using safe and
aesthetically pleasing designs with appropriate municipal landscaping standards.
Ensure that detention facilities that require regular ongoing maintenance do not
encroach into designated park or conservation areas.
Stormwater restrictive covenants and fencing may be required to ensure appropriate
protection of stormwater management controls and facilities. In addition, ongoing
maintenance requirements as well as local area service agreements may be required as
part of the ongoing maintenance requirements associated with stormwater management
covenants.
For large scale or multi phase developments, pre and post development monitoring of water volumes
and water quality may have to be prepared by the engineer of record to help determine the adequacy
of the existing and/or proposed stormwater facilities.