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Vegetated Filter Strip System Design Manual
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| Author: | Robert P. Stone, P. Eng., Engineer, Soil/OMAFRA |
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| Creation Date: | 04 July 2005 |
| Last Reviewed: | 16 June 2006 |
This manual has been developed to:
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.
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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.
The VFS treatment technology practice applies to:
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:
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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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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.
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.
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.
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.
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:
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.
Similar to the management of other nutrients, alternative management includes:
These alternative management options do not replace the requirements
of Section 81 of Regulation 267/03, as amended.
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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
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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.
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.
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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.
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OMAFRA have a number of Best Management Practices handbooks available, including:
Additional fact sheets on other topics include:
BMP books and fact sheets are available through OMAFRA resource centres,
or from the OMAFRA website.
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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:
OMAFRA resource centres can provide a list of laboratories suitable
for soil sampling or check the OMAFRA website.
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