Vegetated Filter Strip System Design Manual
Introduction and Background
1. Introduction and Background
1.1 Purpose of Manual
This manual has been developed to:
- illustrate and describe the key components of a farm-based Vegetated
Filter Strip (VFS) system
- allow farm owners/operators and other rural landowners the opportunity
to carry out a preliminary assessment of the applicability of a
VFS system (for their specific farmstead)
- outline the detailed design process for the development of a VFS
system for managing agricultural runoff
This manual also provides case studies that show common design scenarios.
In Section 1, the manual provides information that defines the purpose
and function of a VFS system and its primary components, outlines,
and permitted applications. It also discusses the regulatory framework
surrounding the development of VFS systems.
Section 2 describes each of the VFS system components and outlines
the design considerations associated with each component.
Section 3 outlines the detailed engineering criteria and methodology
for the design of a VFS system by a qualified professional. This section
explores the use of VFS systems, outlines design guidelines that can
be followed by the user to lay out a farm-based VFS system, and provides
design calculations to determine the details of the VFS system.
Section 4 includes a Design Guide, which provides a step-by-step
process for working through the design of a VFS system.
Section 5 provides case studies of two VFS systems, along with detailed
design calculations.
Supporting documentation related to the design and implementation
of a VFS system is included in Section 6, Design Tables. Table 6.1
gives the maximum runoff storage/settling volume for various centres
in Ontario using the conservative method. Table 6.2 gives the minimum
storage/settling volume required and peak discharge rate using the
rational method. Table 6.3 gives the area required for an infiltration
area based on saturated hydraulic conductivity of soil texture classes
and discharge flow rates.
A Glossary is included in Appendix A at the end of the manual.
1.2 Purpose of VFS System
The purpose of the VFS system is to treat agricultural runoff (impacted
by animal manure) by reducing loading of nutrients, organic matter,
pathogens and other associated contaminants.
1.3 Application of VFS Systems
The VFS treatment technology practice applies to:
- the treatment of runoff from outdoor livestock yards or outdoor
confinement areas lined with concrete or equivalent non-porous material
- the treatment of runoff from permanent solid manure storage facilities
lined with concrete or equivalent non-porous material
VFS systems are typically suitable for small to medium-sized operations,
due to the quantity of runoff generated and the size of the VFS system
components required. VFS systems can also work for large operations;
however, larger pumps, piping systems, etc. may be needed.
It is very important to note that all other types of wastewater (e.g.,
milking centre washwater, etc.) and clean runoff (e.g., rainfall water
from roofs, unpolluted surface runoff) generated on-farm must be excluded
from VFS systems at this time. This is due to:
- permitting issues
- increased loading issues
- unnecessarily high loading rates of clean water
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1.4 Definition of VFS System
A VFS system collects, temporarily stores, and transports agricultural
runoff generated from an outdoor livestock yard/outdoor confinement
area or a permanent solid manure storage facility to an infiltration
area. The VFS system is composed of a series of components that serve
the following primary functions:
1. Collect and temporarily store agricultural runoff
2. Screen out solids from agricultural runoff
3. Control rate of release of nutrients, organic matter, and pathogens
in agricultural runoff
4. Transport agricultural runoff to an infiltration area (via gravity
or pump)
5. Distribute flow evenly across infiltration area
6. Allow runoff to infiltrate into soil within infiltration area
The infiltration area is a densely vegetated (planted) strip of land,
engineered and constructed to accept and manage runoff through settling,
filtration, absorption and infiltration processes. The VFS system
is designed to be "zero discharge." This means that the
VFS system accommodates all of the agricultural runoff that it receives,
without discharging any to surface water. Limitations are outlined
in this manual to ensure that ground water quality is also protected.
Figure 1-1 "Before" and "After"
Schematic
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1.5 Alternatives to VFS System
A runoff management system for a permanent solid nutrient storage
facility, a concrete-lined farm yard, or a permanent outdoor confinement
area should be capable of preventing, collecting, treating, or containing
runoff and consist of at least one of the following components.
1.5.1 Roof
Covering the entire area will prevent entry of precipitation, when
upslope water has also been diverted away from the facility or yard.
Clean roof runoff does not require treatment, and therefore no additional
runoff management would be required if the area is covered. It is
good practice to prevent rainwater from entering the feedlot by using
gutters and downspouts to handle water from building rooftops.
1.5.2 VFS System or Equivalent
Vegetated filter strip systems or an equivalent system, e.g., constructed
wetland, both of which are designed by a qualified professional and
capable of minimizing the effect of runoff on surface water, are acceptable
runoff management systems.
1.5.3 Storage and Land Application
Runoff collection and storage systems must have the capacity to contain
runoff generated by the facility, yard, or area, as the case may be,
for the storage period required of 240 days, or as required by Section
69 of Regulation 267/03, as amended. Livestock yard and permanent
solid manure storage runoff could be collected and conveyed to liquid
manure or dedicated storage facilities for subsequent land application,
or directly land applied. Phased-in operations must meet the requirements
of the Nutrient Management Act, and associated Regulation and Protocols,
including the storage period required by Section 69 of Regulation
267/03, as amended (240 days with exceptions, depending on the period
of use of an outdoor containment area, nutrient application schedule,
temporary storage units, transfers out, etc). For farms with Nutrient
Management Plans, the nutrient content of the land-applied runoff
must be accounted for in the plan.
1.5.4 Permanently Vegetated Area
If upslope water is diverted away from the facility, yard or area,
a permanently vegetated area may be an option for managing runoff.
This option does not apply to the following facilities:
- a permanent solid nutrient storage facility where the runoff generated
by 300 m2 (3,229 ft2) or more of the facility
is channelled through a single flow path;
- a permanent outdoor confinement area where the number of farm
animals kept in the area is sufficient to generate at least 150
nutrient units annually; or
- a permanent outdoor confinement area where the runoff generated
by 2,000 m2 (21,528 ft2) or more of the confinement
area is channelled through a single flow path.
In addition, the permanently vegetated area must be located on a
minimum of 0.5 m of soil and must meet a number of restrictions for
setback distances and flow path requirements. Consult Regulation 267/03,
as amended, Section 81 for specific details.
1.5.5 Alternative Management Options
Similar to the management of other nutrients, alternative management
includes:
- transferring runoff to other farm units for storage and land application
- designing and building an on-site treatment facility
- using other natural treatment systems such as wetlands
- using a broker for management
These alternative management options do not replace the requirements
of Section 81 of Regulation 267/03, as amended.
1.6 Abbreviations
BMP-Best Management Practices
MOE-Ontario Ministry of the Environment
NMA-Nutrient Management Act, 2002
NMP-Nutrient Management Plan
NMS-Nutrient Management Strategy
NU-Nutrient Units, as defined under the NMA
OCA-Outdoor Confinement Area
OMAFRA-Ontario Ministry of Agriculture, Food and Rural Affairs
OWRA-Ontario Water Resources Act
VFS-Vegetated Filter Strip
1.7 Regulatory Framework
1.7.1 Legislation
The Nutrient Management Act, 2002 (NMA) sets clear and consistent
standards for managing nutrients on farms. The act is intended to
be a detailed province-wide approach to managing all nutrients on
agricultural land. The goal of the act is to protect soil and water
quality in Ontario's rural environment, ensuring farmers can invest
in and operate their farms with confidence. The Ontario Ministry of
Agriculture, Food and Rural Affairs (OMAFRA) and the Ministry of the
Environment (MOE) are responsible for governing the act, as well as
the 12-part Regulation (Ontario Regulation 267/03, as amended) that
outlines standards and the two protocols (Nutrient Management and
Sampling & Analysis), which provide more detail to the Regulation.
The Regulation and related protocols were enacted July 1, 2003, and
came into effect September 30, 2003.
The Regulation addresses the management of manure, and other prescribed
materials, that can be land applied to enhance crop production. A
Nutrient Management Strategy (NMS) is a document prepared by agricultural
operations that generate nutrients. The NMS describes the volume and
characteristics of those materials, as well as how they should be
stored and utilized. A Nutrient Management Plan (NMP) documents how
the nutrients should be applied to the land. Specifically, it is an
assessment of what application rate is appropriate for the land base,
and the crops to be grown, as well as any other standards that must
be followed, such as separation distances or waiting periods.
Nutrient Units (NU) are utilized to categorize the size of farms,
and relate to the implementation schedule for NMS and NMP. A nutrient
unit is the amount of manure that gives the fertilizer replacement
value of the lower of 43 kg (95 lb) of nitrogen or 55 kg (121 lb)
of phosphate. Table 3.1 in the Nutrient Management Protocol can help
determine the number of NU on a farm. The total number of NU will
determine whether a livestock operation is regulated.
As of December 31, 2005, all farm operations that apply for a building
permit for any building or structure that is used to house farm animals
or to store manure, or that construct an earthen storage, will require
an approved NMS from OMAFRA if there are more than five NU on the
farm unit. Consult the OMAFRA website at www.omafra.gov.on.ca or call
the Nutrient Management hotline at 1-866-242-4460 for more precise
information on phasing in of farm operations.
Once an agricultural operation is captured by the Regulation (e.g.,
it is required to comply with the NMS and NMP in place), the farm
owner/operator is also responsible for managing runoff associated
with the storage of nutrients. This means that, once an NMS or NMP
is required by the Regulation, a permanent solid nutrient storage
facility must have a runoff management system. An outdoor confinement
area or an impermeable farm animal yard must also be equipped with
a runoff management system. Section 81 of Regulation 267/03, as amended,
provides specific details.
A runoff management system must be capable of handling all the runoff
generated by a farm animal yard or permanent solid manure storage
facility. A vegetated filter strip system, designed by a qualified
professional, is recognized by Regulation 267/03, as amended, as an
appropriate runoff management system. This manual provides guidance
for the design, construction and operation of a VFS system.
1.7.2 Approval Process
Under Section 53 of the Ontario Water Resources Act (OWRA),
as of January 2006, farmers require approval for the installation
of a VFS system. For any installations being installed, farmers must
apply for and comply with the Certificate of Approval issued under
the OWRA by the Ministry of the Environment (MOE). There is no fee
for applying for this Certificate of Approval. Issuing an OWRA approval
can take a significant amount of time so it is important to plan the
VFS system well in advance. A new process has been introduced whereby
applications for Certificate of Approval for installation of VFS systems
will be submitted to OMAFRA for technical review. OMAFRA will provide
recommendations to the MOE for consideration for approval. This should
streamline the system, so that approvals can be issued in a timelier
manner. The MOE would still issue the Certificate of Approval. For
updates, check the OMAFRA website at www.omafra.gov.on.ca or contact
an OMAFRA resource centre.
1.8 Funding Assistance
Funding assistance is available for farmyard runoff control projects
through the Canada-Ontario Environmental Farm Plan Program. The Ontario
Soil and Crop Improvement Association administers the funding and
overall delivery of the federal funding program.
By accessing federal funding, farmers are eligible for assistance
of 50 per cent of the cost of a vegetated filter strip system to a
maximum of $20,000.
For more information on the federal funding available and to apply
for funding, contact the OSCIA at www.ontariosoilcrop.org or 1-519-826-4214.
1.9 Best Management Practices/Related OMAFRA
Literature
OMAFRA have a number of Best Management Practices handbooks available,
including:
- Buffer Strips (BMP 15)
- Manure Management (BMP 16)
- Nutrient Management (BMP 05)
- Nutrient Management Planning (BMP 14)
- Soil Management (BMP 06)
- Water Management (BMP 07)
Additional fact sheets on other topics include:
- Handling Milking Centre Washwater in an Environmentally Responsible
Manner (Order No. 04 019)
- Nutrient Management Act 2002, Constructing Hydraulically Secure
Liquid Nutrient Storage Facilities (Order No. 06-035)
BMP books and fact sheets are available through OMAFRA resource centres,
or from the OMAFRA website.
1.10 Utilization of Professional Design,
Engineering, Site Assessment, and Construction Services
Farm owners/operators and other rural landowners will be required
to retain professional services for investigation, design development,
and possibly construction of a VFS system. These services may include
a professional engineer, hydrogeologist, geoscientist, laboratory
and/or contractor.
Information on selecting and retaining professional services can
be obtained from the following OMAFRA fact sheets:
- Hiring a Practicing Professional Engineer for Farm Projects (Order
No. 95-027)
- How to Choose a Consultant: A Resource for Your Community or Organization
(Order No. 98-053)
OMAFRA resource centres can provide a list of laboratories suitable
for soil sampling or check the OMAFRA website.
Related Links
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