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Practices not being constructed as designed or with specified materials; Lack of erosion and sediment controls (ESCs) during construction; and/or Lack of rigorous inspection prior to assumption. Built according to approved plans and specifications; Installed at an appropriate time during overall site construction and with protective measures Fully operational and not in need of maintenance or repair at the time of assumption by the
→Overview
Integration of Low Impact Development (LID) best management practices (BMPs) into stormwater management (SWM) systems is widely advocated to better address the potential stormwater-related impacts of urbanization on the health of receiving waters. A substantial amount of guidance is available on the planning and design of LID BMPs ([https://sustainabletechnologies.ca/app/uploads/2013/01/LID-SWM-Guide-v1.0_2010_1_no-appendices.pdf CVC & TRCA, 2010)<ref> CVC and TRCA. 2010. Low impact Development Stormwater Management Planning and Design Guide. Version 1.0. https://sustainabletechnologies.ca/app/uploads/2013/01/LID-SWM-Guide-v1.0_2010_1_no-appendices.pdf</ref> and their construction ([https://cvc.ca/wp-content/uploads/2013/03/CVC-LID-Construction-Guide-Book.pdf CVC, 2012])<ref> CVC. 2012. Low Impact Development Construction Guide. Version 1.0. https://cvc.ca/wp-content/uploads/2013/03/CVC-LID-Construction-Guide-Book.pdf</ref> and some municipalities and conservation authorities commonly require them to be a part of new SWM systems.
Integration of Low Impact Development (LID) best management practices (BMPs) into stormwater management (SWM) systems is widely advocated to better address the potential stormwater-related impacts of urbanization on the health of receiving waters. A substantial amount of guidance is available on the planning and design of LID BMPs ([https://sustainabletechnologies.ca/app/uploads/2013/01/LID-SWM-Guide-v1.0_2010_1_no-appendices.pdf CVC & TRCA, 2010)<ref> CVC and TRCA. 2010. Low impact Development Stormwater Management Planning and Design Guide. Version 1.0. https://sustainabletechnologies.ca/app/uploads/2013/01/LID-SWM-Guide-v1.0_2010_1_no-appendices.pdf</ref> and their construction ([https://cvc.ca/wp-content/uploads/2013/03/CVC-LID-Construction-Guide-Book.pdf CVC, 2012])<ref> CVC. 2012. Low Impact Development Construction Guide. Version 1.0. https://cvc.ca/wp-content/uploads/2013/03/CVC-LID-Construction-Guide-Book.pdf</ref> and some municipalities and conservation authorities commonly require them to be a part of new SWM systems.
However, even with sound design, LID BMPs may not provide the intended level of treatment if they
However, even with sound design, LID BMPs may not provide the intended level of treatment if they are not installed properly or protected from damage during construction. Experiences with early applications have shown that failures are often due to:
are not installed properly or protected from damage during construction. Experiences with early
*Practices not being constructed as designed or with specified materials
applications have shown that failures are often due to:
*Lack of erosion and sediment controls (ESCs) during construction; and/or
*Lack of rigorous inspection prior to assumption.
A 2009 survey of stormwater BMPs in the James River watershed (Virginia) by the Center for Watershed Protection found approximately half (47%) of the 72 BMPs deviated in one or more ways from the original design, or were receiving inadequate maintenance (CWP, 2009). Similar results have been revealed from surveys of stormwater detention ponds in Ontario (Drake et al., 2008; LSRCA, 2011), highlighting the need for thorough inspections of BMPs prior to assumption and a proactive approach to stormwater infrastructure operation and maintenance. Therefore, it is important to conduct timely inspections during construction and detailed inspection and testing prior to assumption to ensure that LID BMPs are:
A 2009 survey of stormwater BMPs in the James River watershed (Virginia) by the Center for
*Built according to approved plans and specifications
Watershed Protection found approximately half (47%) of the 72 BMPs deviated in one or more ways
*Installed at an appropriate time during overall site construction and with protective measures to minimize risk of siltation or damage; and
from the original design, or were receiving inadequate maintenance (CWP, 2009). Similar results have
*Fully operational and not in need of maintenance or repair at the time of assumption by the property owner or manager.
been revealed from surveys of stormwater detention ponds in Ontario (Drake et al., 2008; LSRCA,
2011), highlighting the need for thorough inspections of BMPs prior to assumption and a proactive
Like all stormwater BMPs, LID practices are designed to retain pollutants carried by urban runoff and all have a finite capacity to perform this function in the absence of maintenance, until their treatment performance declines or they no longer function as intended. Their functional and treatment performance will only be sustained over the long term if they are adequately inspected and maintained. Under the Ontario Water Resources Act, provincial approvals for SWM facilities and BMPs (i.e., Ontario Ministry of the Environment and Climate Change’s Environmental Compliance Approvals process) typically make the property owner responsible for all inspection and maintenance tasks and associated record keeping (Zizzo et al., 2014). A proactive, routine inspection and maintenance program will also:
approach to stormwater infrastructure operation and maintenance.
Therefore, it is important to conduct timely inspections during construction and detailed inspection
*Identify maintenance issues before they significantly affect the function of the BMP
and testing prior to assumption to ensure that LID BMPs are:
*Help to optimize the use of program resources by providing the feedback needed to determine when structural repairs are needed and to adjust the frequency of routine inspection and maintenance tasks where it is warranted; and
*Help to improve BMP design guidance and develop standards.
to minimize risk of siltation or damage; and
Unlike conventional SWM systems that centralize treatment facilities in few locations on publicly owned land (e.g., detention ponds) an LID design approach involves smaller scale practices distributed throughout the drainage area, potentially on both public and private land. Implementing an LID approach to system design has major implications on municipalities and property managers with respect to operating the stormwater infrastructure they are responsible for, as it increases the number and types of BMPs to be tracked, inspected and maintained.
property owner or manager.
This Inspection and Maintenance (I&M) page is intended to assist users (municipalities, consultants and property managers) with developing their capacity to integrate LID SWM BMPs into their projects and/or larger infrastructure asset management programs. Sections below provide:
Like all stormwater BMPs, LID practices are designed to retain pollutants carried by urban runoff and
*Guidance on designing an effective LID BMP inspection and maintenance program
all have a finite capacity to perform this function in the absence of maintenance, until their treatment
**Based on experiences and advice from jurisdictions in Canada and the United States, and adapted to an Ontario context.
performance declines or they no longer function as intended. Their functional and treatment
performance will only be sustained over the long term if they are adequately inspected and
*Recommended standard protocols for inspection, testing and maintenance of the following types of structural LID BMPs:
maintained. Under the Ontario Water Resources Act, provincial approvals for SWM facilities and BMPs
**Bioretention and dry swales
(i.e., Ontario Ministry of the Environment and Climate Change’s Environmental Compliance Approvals
**Enhanced swales
process) typically make the property owner responsible for all inspection and maintenance tasks and
**Vegetated filter strips and soil amendment areas
associated record keeping (Zizzo et al., 2014). A proactive, routine inspection and maintenance
**Permeable pavements
program will also:
**Underground infiltration systems
**Green roofs; and
**Rainwater cisterns
*Guidance on recommended inspection, testing and maintenance tasks specific to each BMP type
*A summarization of staff skills and equipment required to complete them
*sampling and testing procedures and protocols
*Estimated costs over a 50 year BMP life cycle.
Drawing upon the information provided on this; and its subsequent page(s) municipalities and property managers will be better able to design or adapt their infrastructure asset management programs to include LID BMPs effectively, and understand the tasks, procedures and estimated costs associated in adequately inspecting and maintaining them.
==LID Practices' Inspection & Maintenance==
==LID Practices' Inspection & Maintenance==