Conveyance and End-of-Pipe Measures for Stormwater - FCM

1. General
1.1 Introduction
Urbanization increases stormwater quantity
and affects stormwater quality, producing
significant hydrologic and environmental
changes that can potentially result in adverse
impacts on streams, other receiving waters,
and their habitats. As an area develops
or urban intensification takes place,
undisturbed pervious surfaces become
impervious with the construction of homes,
buildings, roads, parking lots, and other
structures. These hard surfaces increase
stormwater runoff volume and flow rates,
and impact the pollutant concentrations
associated with runoff.
To address stormwater management
objectives, stormwater runoff considerations
need to be integrated fully into site planning
and design processes. This involves a more
comprehensive approach to site planning
and a thorough understanding of the physical
characteristics and resources of the site.
Normally called “integrated stormwater
management planning,” this approach treats
stormwater as a resource to be protected
and includes protection of property, aquatic
resources, and water quality as complementary
objectives. Stormwater should be managed
on a watershed basis, within the broad
framework of land management and ecosystem
planning or, at least, within a master drainage
plan. This planning should be based
on a hierarchy of principles that include
pollution prevention, and source, on-site,
conveyance, and end-of-pipe control
management practices (UDFCD, 2004;
Urbonas and Roesner, 1993).
1.2 Scope
This best practice is linked to the best
practices for Stormwater Management
Planning (InfraGuide, 2004) and Source
and On-Site Controls for Municipal Drainage
Systems (InfraGuide, 2003).
Conveyance control best management
practice facilities are located within the
drainage system where flows are concentrated
in a flow conveyance route. End-of-pipe control
facilities are at the end of the flow conveyance
route. Both techniques can provide flow
attenuation, major flow conveyance,
and water quality enhancement of stormwater
before discharge into a receiving water body.
Both of these measures of source and on-site
control measures.
The rationale to implement conveyance and
end-of-pipe controls is first presented along
with criteria for selecting the most appropriate
measures and techniques depending on site
and watershed characteristics. A description
of the state-of-art methodologies for
conveyance and end-of-pipe controls
is then given, based on available and tested
approaches. The degree of effectiveness
and costs for different facilities, and related
operation and maintenance issues are also
presented, as they are essential in the
decision-making and implementation process.
Design aspects and references related
to cold-climate conditions are also highlighted
to reflect a northern perspective.
Conveyance and End-of-Pipe Measures for Stormwater Control — July 2005 11
1. General
1.1 Introduction
1.2 Scope
To address
stormwater
management
objectives,
stormwater runoff
considerations
need to be
integrated fully
into site planning
and design
processes.