low impact development training maintenance & monitoring: environmental & facility managers...
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Low Impact Development Training Maintenance & Monitoring: Environmental & Facility Managers
Presented by:
The Low Impact Development Center, Inc. A non-profit water resources and sustainable design organizationwww.lowimpactdevelopment.org
Copyright 2009 Low Impact Development Center, Inc.
Objectives
• Maintenance for Bioretention, Pavers, Green Roofs, Filter strips and buffers
• Corrective Actions• General Environmental Monitoring
Copyright 2009 Low Impact Development Center, Inc.
• Regulatory requirement – NPDES MS4 permit– Other State storm water regulations (new)– Documentation may be required
• Necessary to continue function as designed• Proper maintenance lowers long term costs • Less costly to maintain than repair or replace
Maintenance Drivers
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Maintenance – Bioretention
• Primary maintenance requirement - regular inspection and repair / replacement of damaged components
• Can be incorporated into regular landscaping maintenance contract, as the routine periodic maintenance for bioretention areas is similar to what is required of any landscaped area
Copyright 2009 Low Impact Development Center, Inc.
Planting Maintenance
• Routine maintenance should include a biannual health evaluation of the plantings, and removal and replacement of any dead or diseased vegetation.
• The use of native plant species in the bioretention cell will reduce fertilizer, pesticide, water, and overall maintenance requirements.
• Level of pollutants in the soil can become toxic, impair plant growth
Maintenance – Bioretention
Copyright 2009 Low Impact Development Center, Inc.
Maintenance – Bioretention
Planting maintenance
• Immediately after installation, water plant material for 14 consecutive days (unless sufficient natural rainfall).
• When trees have taken root, or at least by 6 months, remove stakes and wires
• Visually inspect vegetation for disease or pest problems at least once in the spring, once in the fall, and more frequently in the summer. If treatment is warranted, use the least toxic approach
• During extended drought, look for physical signs of stress (unrevived wilting; yellow, spotted or brown leaves; loss of leaves, etc.). Water in the early morning if needed
• Prune excess growth annually in the spring and throughout the growing season if desired. Trimmed materials may be recycled back in with replenished mulch or landfilled if there is a concern of heavy metals accumulation.
• Weed regularly, as necessary
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Maintenance – Bioretention
Requirements Testing Remediation
Soil pH should be between 5.5 and 6.5.
Obtain a kit and instructions from the State Cooperative Extension Office.
Apply the necessary amount of limestone to get the pH in the correct range.
Soils• Visually inspect and repair erosion at inflow points once in the spring and once in the fall, at a minimum. • Use small stones to stabilize erosion along drainage
paths. • Check the soil’s pH once or twice a year. • Apply an alkaline product, such as limestone, if needed.
Copyright 2009 Low Impact Development Center, Inc.
Maintenance – Bioretention
Soils - Maintain Infiltration Rates• Runoff from impervious surfaces is directed to bioretention
cells to infiltrate through the soil medium
• Once the infiltration capacity of the soil medium is exceeded, storm water begins to pool at the soil’s surface
• Ponding should only last 4-6 hours
• Mosquitoes larva need 4+ days of standing water
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Soils – Corrective Action• Depending on pollutant loads, soils may need to be replaced within 5-30
years of construction.• If standing water consistently over 4-6 hrs:
– Clear the underdrain of potential clogs– Check filter fabric above the underdrain– Remove mulch and rake surface to remove surface blockages – Last resort - remove the soil mixture
• Before removing soil mixture, analyze for clay content and hazardous content
• If greater than 15% clay content, then:– Temporarily block end of discharge pipe, install appropriate E&S controls– Carefully dig up plants so that root systems are maintained (and return to cell
following soil replacement)– Remove soil and dispose appropriately as clean fill or in an approved landfill – Inspect pipe and gravel layer, if pipe is clogged, then wash the gravel layer
with a high-pressure hose – this should clean the pipe– Place new soil in the cell and replant vegetation
Maintenance – Bioretention
Copyright 2009 Low Impact Development Center, Inc.
Maintenance – Bioretention
Mulch Layer• Uniformly applied approximately 2 to 3 inches deep. Do
not pile the mulch around trees or other plantings• Fresh bark mulch (either standard landscape fine
shredded hardwood mulch or hardwood chips). Make sure it is free from weed seeds, soil, roots or any other substance not consisting of bole, branch wood, or bark Do not use grass clippings as mulch
• Every 6 months, in the spring and fall, add a fresh mulch layer. Once every 2 to 3 years, in the spring, remove the old mulch layer before applying the new one
Copyright 2009 Low Impact Development Center, Inc.
Description Frequency
1. Soil
a) Inspect and Repair Erosion Spring and fall
b) Check pH Once a year
2. Organic Layer
a) Re-mulch any void areas As needed
b) Add new mulch layer Spring and fall
c) Remove old mulch layer Three (3) years
3. Plants
a) Water plant material for fourteen consecutive days after planting has been completed unless there is sufficient natural rainfall
Immediately afterCompletion ofproject
b) Remove stakes and wires after six months After rooting
c) Inspect for disease/pest problems Spring/summer/fall
d) Treatment of diseases As needed, refer tomanufacturer
Maintenance Schedule – Bioretention
Copyright 2009 Low Impact Development Center, Inc.
3. Plants (continued)
e) Removal and replacement of all dead and diseased vegetation considered beyond treatment
Spring and fall
f) During times of extended drought, look for signs of stress Water as needed.
Summer
g) Weed and prune excess growth Spring/summer
h) FertilizeAs needed, refer to manufacturer
i) Remove tags After warranty
4. General
a) After major rainstorms, inspect site and make sure drainage paths are clear and that ponding water dissipates over time. Clear the drainage path of any accumulated sediment or debris. Seek remediation if drawdown times are consistently much longer than 4-6 hours
After major rainstorms
Maintenance Schedule – Bioretention
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Maintenance – Permeable Pavers
• Primary maintenance requirement - clean the surface drainage voids
• Can be incorporated into regular street sweeping program
• Annual inspections
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• Inspections • Routine maintenance is key:
– Conventional street sweepers equipped with vacuum sweepers and high-pressure water can used to restore permeability
– Street sweeping frequency varies depending on drainage area inputs (leaf debris, erosion, etc.). An active street sweeping program in the site’s drainage area will also help to prolong the functional life of the pavement
– If necessary, add additional gravel chips to fill pore spaces after vacuum sweeping
• In case of localized settling, individual paver blocks can be removed, new gravel added, and the blocks replaced
Maintenance – Permeable Pavers
Copyright 2009 Low Impact Development Center, Inc.
• Restrict use by heavy vehicles
• Limit use of de-icing chemicals and sand
• Implement stringent sediment control plan
• Failure of systems:– poor design– inadequate construction
techniques– low permeability soils– heavy vehicular traffic– resurfacing with nonporous
materials
Maintenance – Permeable Pavers
Copyright 2009 Low Impact Development Center, Inc.
Maintenance Schedule Permeable Pavers
Description Frequency
Initial Inspections Monthly for first several months
following construction
Vacuum sweeping and high
pressure hosing
4 times/year
Encourage active street cleaning
in the site’s area
Regularly
Annual inspections Yearly, after large storms
Fill potholes and cracks As needed
Address spot-clogging problems
by drilling holes
As needed
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Maintenance – Permeable Pavement
Routine Maintenance• Similar to permeable
pavers • Recommended: Vacuum
sweep twice per year
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Maintenance – Permeable Pavement
Corrective Action• Fill potholes and
cracks with permeable patching mixes
• Fix spot clogging by drilling ~0.5-inch holes through the porous pavement layer every few feet
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• Virtually maintenance free• Periodic inspections of system components• Most important - ensure spigot is set to slowly
release the barrel’s water
Maintenance – Rain Barrels & Cisterns
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• Bimonthly inspection:– rain barrel is free of debris– filtration screen and downspout not clogged– overflow system properly directing the water away from
siding and foundations and not causing erosion problems
– mosquito screen properly installed
• Once a year, wash the barrel with mild (preferably biodegradable) soap and water
Maintenance – Rain Barrels & Cisterns
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Corrective Action• There are few mechanical parts on cisterns or rain barrels • Spigot, valve, and screen replacements can be ordered
from the manufacturer • Cracked rain barrel = replace rain barrel
• Large cisterns constructed out of materials such as metal or concrete may need repairs to walls by parging (for concrete) or welding (for metal)
Maintenance Schedule – Rain Barrels & Cisterns
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Description Frequency
Make use of the stored water! Regularly
Check for clogging of the entrance/outlet points Every other month
Check for proper diversion of the overflow system Every other month
Check for proper installation of the mosquito screenEvery few weeksin the summer
Wash the barrel with mild soap and waterAnnually,preferably in thespring
Prepare the system for winter conditions Pre-freezing
Maintenance Schedule – Rain Barrels & Cisterns
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• The maintenance requirements for street tree-box filters are similar to those of other bioretention devices, although less complicated
Maintenance – Street Tree-Box Filter
Copyright 2009 Low Impact Development Center, Inc.
Inspections• Bimonthly• If possible, conduct during or immediately after a
rain event• Debris removal:
– Inspect system and clear drainage path of accumulated leaves, debris, and trash
– Remove accumulated materials on the top layer of the soil media, test, and dispose
– Inspect discharge pipe for clogging and clean if necessary
Maintenance – Street Tree-Box Filter
Copyright 2009 Low Impact Development Center, Inc.
Maintenance – Street Tree-Box Filter
Planting Maintenance
• Same maintenance as bioretention cells
Soils Maintenance• Same maintenance as bioretention cells• Runoff bypassing the tree-box = clogged inflow area, or
reduced infiltration properties of soil mixture• Soils analysis, disposal requirements, and corrective
measures are the same as bioretention cells • For remediation assistance, contact Americast at
(800) 999-2278 or (804) 798-6068
Copyright 2009 Low Impact Development Center, Inc.
• First two years of maintenance typically included with the purchase of single and multiple-unit tree box filters – These would include removal of trash, debris and sediment,
replenishment of the mulch, and care or replacement of plants
• Annual maintenance = $500 per unit (performed by the manufacturer) or $100 per unit (performed by the owner) (sample cost estimate based on the Filterra™ Stormwater Bioretention Filtration System.)
Maintenance – Street Tree-Box Filter
Copyright 2009 Low Impact Development Center, Inc.
Corrective Actions• Plants may have to be replaced because:
– they have overgrown the filter– environmental stress– they are mistaken as weeds growing through the
grate, and are removed
Maintenance – Street Tree-Box Filter
Description Frequency
1) Overall system
a) Inspect and clear drainage paths Every other month
2) Plants
a) Water plant material for fourteen consecutive days after planting
has been completed unless there is sufficient natural rainfall
Immediately after completion ofproject
b) Inspect for disease/pest problems Spring/summer/fall
c) Treatment of diseases As needed, refer to manufacturer
d) Removal and replacement of all dead and diseased vegetation considered beyond treatment
Spring and fall
e) During times of extended drought, look for signs of stress. Water
as needed. Summer
f) Weed and prune excess growth Spring/summer
3) General
a) During major rainstorms, inspect site and make sure that infiltration is occurring as expected.
Every other month.
b) Clear the top layer of soil of accumulated material As needed
c) Clean the drainage pipes As needed
d) Seek remediation if infiltration function is not adequate after cleaning efforts
As needed
Maintenance Schedule - Street Tree-Box Filter
Copyright 2009 Low Impact Development Center, Inc.
Maintenance - Dry Wells
• Minimal maintenance:– Clearing the rain gutters of
debris that could clog the downspout
• Corrective Actions: – Can clog over time if there
is extensive loading of fine-grained sediment
– Standing water at the surface indicates clogging– Dig out gravel, then excavate to remove sediment and uncover a
layer of soils that has sufficient infiltration capacity
Copyright 2009 Low Impact Development Center, Inc.
Maintenance - Filter Strip
• Incorporate into landscaping contract • Inspect twice annually for erosion or damage to vegetation• Additional inspections after periods of heavy runoff • Requires mowing, irrigation, and weeding • Mowing may only be necessary 1x or 2x per year for safety
and aesthetics or to suppress weeds and woody vegetation • Periodic litter removal, and always prior to mowing
Copyright 2009 Low Impact Development Center, Inc.
Maintenance - Vegetated Buffers
Maintenance Program• Monitor and manage to maintain maximum water quality benefits
and, where desired, wildlife habitat benefits• Inspections – at least annually, and always within a few days after
severe storms. Look for evidence of sediment deposition, erosion, or development of concentrated flow channels
• Aggressive weed and invasive species control• Avoid working in riparian area between April 15 and August 15, when
a variety of animals are bearing their young
• Corrective Actions– If the buffer width is sufficient,
Changes in hydrology, drought, over-grazing or natural disasters such as flooding or fire may require the replanting or reestablishment of the buffer
Copyright 2009 Low Impact Development Center, Inc.
Maintenance - Grassed Swales
Maintenance Objectives:• Keeping up the hydraulic and removal efficiency of the channel• Maintaining a dense, healthy grass cover
Maintenance Program:• Periodic mowing (with grass never cut shorter than the design flow
depth)• Weed control• Watering during drought conditions• Reseeding of bare areas• Clearing of debris and blockages
Corrective Actions:• Remove cuttings from the channel• Remove accumulated sediment • Avoid applying fertilizers and
pesticides
Copyright 2009 Low Impact Development Center, Inc.
Maintenance - Infiltration Trenches
Maintenance Objectives:• Prevent clogging, which may lead to trench failure
Maintenance Program:• Inspect annually• Monitor observation well to confirm
trench is draining properly• Inspect after large storm events• Remove accumulated debris or
material • Stabilize surrounding areas to
eliminate the potential for sediment clogging
Corrective Actions:• If infiltration trench fails, remove clogged stone and sediment• Wash stone to remove sediment and replace
Copyright 2009 Low Impact Development Center, Inc.
Maintenance - Green Roof
• Maintenance requirements for a properly installed, well established vegetated roof are minimal:
• Inspection of roof membrane, the most crucial element of a vegetated roof
• Inspection and preventive maintenance of the drainage layer flow paths
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Maintenance - Green Roof
Corrective Actions• More complex systems may have monitoring devices
incorporated into the membrane• Leak detection systems can be brought to the site to
locate breaches in the membrane• The soil media can be removed & the membrane repaired • Long periods of drought or
loss of soil to high winds may require replacement of the media or replanting
• Schedule supplemental watering during drought periods, or install an irrigation system
Copyright 2009 Low Impact Development Center, Inc.
Stormwater Management Feature Maintenance Contracting and $
• Sustainment (UT/SRM) funds must be used, NOT Environmental
• Enter your SW features into iNFADS- NAVFAC Portal- Account request
• Partner with PW to get your SW features maintained
• SOW, GCE• Landscaping contract, BOS contract, new
Regional Stormwater Maintenance Contract (?)
iNFADS
iNFADS
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Monitoring Programs
• Not typically a regulatory requirement
• Potential requirement for discharges to sensitive or impaired waters
• Monitoring plan shaped by regulatory requirements, site characteristics, parameter(s) of concern, and use of the data
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Water Quantity Monitoring
Monitor the effectiveness of LID features either on a small scale (individual features) or large scale (stream flow):
Small Scale Manual or automatic sampling methods can be used to calculate flow rates upstream and downstream of a LID feature, based on the depth measured using a weir or a rate of flow measured using a conveyance device.
Large ScaleWhere LID features are being installed as retrofits in already developed areas, the effectiveness of the retrofits can be assessed by comparing pre-LID and post-LID flow rates downstream.
Copyright 2009 Low Impact Development Center, Inc.
Water Quality Monitoring
• The same pre- and post-LID samples taken for small scale water quantity monitoring can be used for water quality monitoring
• The Nationwide Urban Runoff Program (NURP) has identified the following “standard pollutants characterizing urban runoff”:
Pollutant Abbreviation
Suspended Solids Concentration SSC
Biochemical Oxygen Demand BOD
Chemical Oxygen Demand COD
Copper Cu
Zinc Zn
Total Phosphorous TP
Soluble Phosphorus SP
Total Kjeldahl Nitrogen TKN
Nitrate + Nitrite NO2 + NO3
Water Quality Monitoring Parameters
Copyright 2009 Low Impact Development Center, Inc.
Training
• Stormwater Training for facility personnel• ECATTS
• Web-based environmental training by media• Approximately 20-min each• Courses:
• Stormwater – Basic Information• Stormwater – Comprehensive Overview• Wetlands• Spill Prevention Control and Countermeasures• Spill Response and Notification
• http://navfac.ecatts.com• Password = “navfac”
• Stormwater Training for Facility Managers
ECATTS