Vegetated Filter Strip System Design Manual
Operation and Maintenance
3.9 Operation and Maintenance
3.9.1 Runoff Area and Storage
(Integrated or External)
Cleaning
For integrated storage facilities, the manure should be removed routinely
from the runoff collection area to maintain a minimum depth and minimize
the nutrient uptake by rainwater.
Diversion of Clean Water
The VFS system will be designed based on the premise that the components
required to service the runoff area in a storm event are in-place
and operating. Ensure that diversion of the upslope water (such as
barn roof runoff) is occurring. Regularly inspect upslope diversion
equipment, such as gutters and roof downspouts.
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3.9.2 Collection/Discharge Bay
Collection/Discharge Bay
The collection/discharge bay must be cleaned regularly to reduce
the potential for clogging the riser pipe and drainpipe orifice. Daily
inspection and maintenance activity is required to achieve this.
Screen Cleaning
Inspect screens after large storm events and clean as required. Periodic
cleaning is also recommended.
Sump Inspection
Routine inspection of the silt level in the sump is required to ensure
that the solids do not interfere with siphon/pump operation and convey
solids to the infiltration area.
3.9.3 Pumps
Controls
The runoff pump operates on a float system, so that the pump starts
and stops are activated automatically by the level of water in the
sump. The control system must be inspected and tested regularly.
Cleaning
The pump requires regular cleaning to prevent interruption to operations
and/or damage. Refer to the manufacturer-supplied pump operations
and maintenance manual.
3.9.4 Piping
Cleaning
Flushing of piping may provide the most effective cleaning method.
This can be achieved by running clean water through the system at
a velocity higher than normally experienced in the system, if possible.
In pumped systems, caution should be taken to maintain flows through
the pump as recommended by the manufacturer.
If particular sections of the piping are clogged, disassemble the
piping and thoroughly clean at these sections.
3.9.5 Infiltration Area
Splash Pad
The splash pad should be regularly inspected. Levelling and removal
of solids and debris may be required.
Spreaders
Periodic maintenance may be required if erosion develops in the spreader.
Therefore, spreaders should be inspected periodically (at least annually)
to confirm that they are level and functioning properly.
Solids Entry and Plugging
If high suspended-solids content runoff is continuously directed
to the infiltration area, it may become clogged as the solids settle.
The appropriate design and maintenance of the runoff and storage/settling
facilities should prevent this from occurring.
If solids are observed on the infiltration area, the upstream contribution
must be investigated. To reactivate the infiltration area, remove
any visible solids, till and re-establish vegetation. Runoff must
be directed to other nutrient management facilities during this maintenance
period. Alternatively, aeration of the infiltration area may be sufficient
to remove blockage..
Maintaining Vegetation
Maintenance of the infiltration area is necessary to ensure a healthy
and vigorous vegetative cover. Routine inspection of the infiltration
area vegetative cover will be required to ensure 100 per cent coverage
and consistent sheet flow. Should small breaks in the vegetative cover
or erosion rills be observed, immediate action to correct the deficiency
is required. During the initial startup period, irrigation of the
infiltration area may be required to promote germination of sown seed.
Liquid manure or other similar nutrients should not be applied to
the infiltration area. However, other fertilizer may be required for
initial establishment of the vegetation. Mowing of the infiltration
area should occur 3-4 times during the growing season and especially
if weed species migrate into the site, or if thatch buildup begins
to smother and limit vegetation density. The harvested crop of hay
from the infiltration area can be used for livestock feed. Every effort
must be made to ensure that any equipment driven on the infiltration
area does not impact the integrity of the sheet flow path, compact
the soil or alter the infiltration area hydraulic conductivity, or
generate rills or ridges parallel to the flow.
Discharge Observations
During the active operating mode, observe the infiltration area regularly
to determine whether it meets the objective of zero discharge (off
the lower end of the infiltration area) for the maximum-design storm.
If discharge is observed, this indicates that the infiltration area
is not operating as designed. Determine the cause and take corrective
action.
If the infiltration area does not operate with zero discharge under
normal operating conditions, it should be removed from service until
the problem is solved, and the runoff should be directed to alternative
storage, use, or disposal to reduce the potential for adverse effect
on the receiving water.
Safety Measures
The infiltration area should fenced to protect it from uncontrolled
grazing. Maintain vegetation by mowing or controlling grazing. Fencing,
berms, and other structural components of the infiltration area should
be inspected regularly to identify any safety concerns.
3.9.6 Winter Operation
Runoff should occur in winter only during periods of warmer weather
(thaws). All piping should be designed to be empty unless flowing.
The sump should be deep enough and covered to prevent freezing of
the pump. If the sump freezes, turn off the pump until the ice melts.
3.9.7 Accessibility
Provide access, as required, to operate and maintain the system.
Minimum access requirements are:
- screens
- collection pipe
- storage/setting basin
- sump
- pump
- conveyance & distribution pipes/channels
- splash pad
- infiltration area
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3.9.8 Safety
Two primary hazards are associated with the VFS system: water and
electricity (for pumped systems). Adequate protection should be provided
to reduce the potential for accidents during and following construction.
The Occupational Health and Safety Act and Regulations for Construction
Projects, available from the Ontario Ministry of Labour, telephone
1-800-268-8013, provide information on the responsibilities of the
constructor.
3.9.9 VFS System Inspection Sheet
Inspect the VFS system on a regular basis to ensure that all the
components are functioning adequately. The following "VFS System
Inspection Sheet" will provide a written record of inspection
activities that have been undertaken.
Vegetative
Filter Strip System Inspection Sheet
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