URBAN BMP COST AND EFFECTIVENESS
SUMMARY DATA
FOR 6217(g) GUIDANCE
POST-CONSTRUCTION STORMWATER
RUNOFF TREATMENT
January 29, 1993
WOODWARD-CLYDE ^
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URBAN BMP COST AND EFFECTIVENESS
SUMMARY DATA
FOR 6217(g) GUIDANCE
* ** ^ • VQ m
library
EPA REGION 4
9th Floor
100 Alabama St. S.W.
Atlanta, GA 30303
POST-CONSTRUCTION STORMWATER
RUNOFF TREATMENT
January 29, 1993
WOODWARD-CLYDE ^
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ACKNOWLEDGEMENTS
The authors of this report were Ms. Lynn Mayo, Mr. Dale Lehman, Mr. Lawrence dinger,
Mr. Brian Donovan, Dr. Peter Mangarella, Ms. Teressa Hua, Mr. Dave Kendziorski, and Mr.
Eric Strecker of Woodward-Clyde. Contributions to this report were also made by Mr. Eugene
Driscoll of Hydroqual and Mr. Thomas Cahill of Cahill Associates.
The authors would like to thank Mr. Robert Goo, Mr. Edward Drabkowski, and Mr. Rod
Frederick of the United States Environmental Protection Agency (EPA); Mr. Robert Iosco of
the Northern Virginia Soil and Water Conservation District; and Mr. Thomas Schueler of
Metropolitan Washington Council of Governments for their guidance and comments during the
development of this document.
The project was funded by the EPA Assessment and Watershed Protection Division.
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TABLE OF CONTENTS
Section Page
1.0 INTRODUCTION 1-1
2.0 EFFECTIVENESS AND COST SUMMARY 2-1
2.1 DESCRIPTION OF POST-CONSTRUCTION STORMWATER
RUNOFF TREATMENT 2-1
2.1.1 Infiltration Basins 2-1
2.1.2 Infiltration Trenches and Dry Wells 2-3
2.1.3 Vegetative Filter Strip 2-4
2.1.4 Grassed Swales 2-5
2.1.5 Porous Pavement 2-6
2.1.6 Concrete Grid Pavement 2-7
2.1.7 Filtration Basins and Sand Filters 2-8
2.1.8 Water Quality Inlet - Catch Basin 2-9
2.1.9 Water Quality Inlet - Catch Basin with Sand Filter 2-10
2.1.10 Water Quality Inlet - Oil/Grit Separator 2-10
2.1.11 Extended Detention Dry Ponds 2-11
2.1.12 Dry Ponds 2-12
2.1.13 Wet Ponds 2-13
2.1.14 Extended Detention AVet Ponds 2-14
2.1.15 Constructed Stormwater Wetlands 2-15
2.2 EFFECTIVENESS 2-15
2.2.1 Infiltration Basins and Infiltration Trenches 2-16
2.2.2 Vegetative Filter Strip 2-18
2.2.3 Grassed Swales 2-19
2.2.4 Porous Pavement 2-20
2.2.5 Concrete Grid Pavement 2-20
2.2.6 Filtration Basin 2-21
2.2.7 Water Quality Inlet - Catch Basin 2-21
2.2.8 Water Quality Inlet - Catch Basin with Sand Filter 2-21
2.2.9 Water Quality Inlet - Oil/Grit Separator 2-22
2.2.10 Extended Detention Dry Ponds 2-22
2.1.11 Wet Ponds 2-22
2.1.12 Extended Detention Wet Ponds 2-23
2.1.13 Constructed Stormwater Wetlands 2-23
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TABLE OF CONTENTS (continued)
Section Page
2.3 COST 2-23
2.3.1 Infiltration Basins 2-24
2.3.2 Infiltration Trenches 2-25
2.3.3 Vegetative Filter Strip 2-25
2.3.4 Grassed Swales 2-25
2.3.5 Porous Pavement 2-25
2.3.6 Concrete Grid Pavement 2-26
2.3.7 Filtration Basin 2-26
2.3.8 Water Quality Inlet - Catch Basin 2-26
2.3.9 Water Quality Inlet - Catch Basin with Sand Filter 2-27
2.3.10 Water Quality Inlet - Oil/Grit Separator 2-27
2.3.11 Extended Detention Dry Ponds 2-27
2.3.12 Wet Ponds 2-27
2.3.13 Extended Detention Wet Ponds 2-28
2.3.14 Constructed Stormwater Wetlands 2-28
3.0 SUMMARY TABLES 3-1
4.0 MANAGEMENT PRACTICES SUMMARY 4-1
4.1 REMOVAL EFFICIENCIES 4-1
4.2 SERIES OF MANAGEMENT PRACTICES 4-2
4.3 MAINTENANCE 4-2
5.0 RETROFIT 5-1
5.1 DESCRIPTION 5-1
5.1.1 Construction or Modification of Pollutant Removal
Facilities 5-1
5.1.1.1 New Facilities 5-1
5.1.1.2 Revise Existing Facilities 5-2
5.1.2 Stabilize Shorelines, Stream Banks and Channels 5-2
5.1.3 Protect And Restore Riparian Forest And Wetland Areas 5-3
5.2 EFFECTIVENESS 5-3
5.3 COST 5-3
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TABLE OF CONTENTS (continued)
Section Page
6.0 REFERENCES 6-1
APPENDICES
A STATE REGULATIONS
B EFFICIENCY DATA
C COST DATA
LIST OF TABLES
TABLE 3-1 ADVANTAGES AND DISADVANTAGES OF
MANAGEMENT PRACTICES 3-3
TABLE 3-2 EFFECTIVENESS OF MANAGEMENT PRACTICES FOR CONTROL
OF RUNOFF FROM NEWLY DEVELOPED AREAS 3-7
TABLE 3-3 COST OF MANAGEMENT PRACTICES FOR CONTROL OF RUNOFF
FROM NEWLY DEVELOPED AREAS 3-12
TABLE 5-1 EFFECTIVENESS OF EXISTING DEVELOPMENT MANAGEMENT
PRACTICES 5-4
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1.0
INTRODUCTION
In November 1990, the U.S. Congress passed the Coastal Zone Act Reauthorization and
Amendments (CZARA). As part of this reauthorization, Congress created a new, distinct
program to address nonpoint source (NPS) pollution of coastal waters (Section 6217). The U.S.
Environmental Protection Agency (EPA) and the National Oceanic and Atmospheric
Administration (NOAA) jointly drafted Proposed Program Guidance for Section 6217. EPA was
given the lead responsibility for developing the Management Measures Guidance required under
Section 6217(g) of CZARA.
EPA established five Federal/State Work Groups to assist in preparation of the 6217(g)
Guidance. Woodward-Clyde has supported the Urban Work Group through the collection and
analysis of information on Best Management Practices (BMPs) used to control urban NPS
pollution. The results of these efforts includes four books that present cost and effectiveness
information on BMPs for:
• Erosion and Sediment Control;
• Post Construction Runoff;
• Onsite Sewage Disposal Systems; and
• Roads, Highways and Bridges.
This report is a summary of the cost and pollutant removal effectiveness information that was
obtained from published literature regarding post-construction stormwater runoff treatment. The
report also contains appropriate management practices and systems of management practices for
the control of NPS pollution after construction and to retrofit existing systems. In accordance
with Woodward-Clyde's scope of work, this document only addresses structural management
practices.
This document contains information from 41 documents. Also, over 150 documents were
reviewed regarding post-construction management practices. The documents were obtained
through literature searches and telephone contacts with all states and territories with approved
Coastal Zone Management Plans. Cost and effectiveness data from the various management
practices presented in the documents were reviewed and analyzed to develop summary
information for the various BMPs. Data were omitted from consideration where substandard
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field technique was used in the collection of the data or if results were influenced by atypical
climatological or site characteristics (e.g. unusually heavy rainfall or prolonged drought). Also,
only management practices that have been applied in the field were considered. Experimental
practices only applied in a research setting were not considered.
This report contains descriptions of the management practices considered, summary cost and
effectiveness information, and recommended practices for use in treating post-construction
stormwater runoff, and retrofit practices for urbanized areas. The Appendix presents the data
analyzed to develop summary cost and effectiveness information.
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2.0
EFFECTIVENESS AND COST SUMMARY
This section describes the types of post-construction stormwater runoff management practices
considered, where and when these practices can be applied, and the cost and effectiveness of
these systems.
Over 150 documents were reviewed and information from 41 documents was used to develop
this effectiveness and cost data. It should be noted that the documents obtained and reviewed
do not include all of the published literature regarding post-construction stormwater runoff
management practices. However, many of the documents obtained were summaries of many
other investigations. The influences of soil type, drainage area, climate and many other site
specific factors on effectiveness of the practices are discussed. Advantages and disadvantages
of the various practices are presented in Table 3-1.
2.1 DESCRIPTION OF POST-CONSTRUCTION STORMWATER RUNOFF
TREATMENT
The following is a description of various post-construction stormwater runoff structural
management practices. In addition to providing pollutant removal, several practices also can
control the post-development peak flow rate which is important for protecting downstream
channels from erosion due to increased velocities and runoff volumes.
2.1.1 Infiltration Basins
Infiltration basins are basins that temporarily store runoff while it percolates into the soil through
the basins' bottom and sides. Infiltration basins should drain within 72 hours and therefore are
generally dry. This is needed to maintain aerobic conditions in order to favor bacteria that aid
in pollutant removal and to ensure that the basin is empty for the next storm (Schueler, 1987).
Infiltration basins must be designed to trap coarse sediment before it enters the basin proper and
clogs the surface soil pores on the basin floor. If there is concentrated flow, a sediment trap
could be used to trap the sediment, and if there is sheet flow, a vegetative filter strip could be
used.
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In-line infiltration basins are typically used for drainage areas from 5 to 50 acres (Schueler,
1987). There must be at least 4 feet of permeable soil (SCS soil group A or B) between the
bottom of the basin and bedrock or highwater table. Infiltration basins are not effective when
the soil is frozen.
The main factors that influence the removal efficiency are the storage volume, basin surface area
and soil percolation rates.
Any runoff that percolates into the ground and reaches surface waters through the groundwater
is commonly assumed to have had the pollutants removed by soil processes such as filtration and
biological action. Therefore, any runoff and pollutants that percolate into the ground are
assumed to be removed. The validity of this assumption depends on the pollutants of concern,
their chemical properties and local conditions.
Operation and Maintenance
Routine maintenance requirements include inspecting the basin after every major storm for the
first few months after construction and annually thereafter, mowing frequently enough to prevent
woody growth, removing litter and debris and revegetating eroded areas. Also, the accumulated
sediment should be removed periodically. The infiltration capacity of a soil will decrease over
time. If the decrease is due to surface clogging the soil can be deeply tilled or excavated and
replaced. Maryland recommends deep tilling every 5 to 10 years (Schueler, 1987). A
nonfunctioning infiltration basin can also be converted into a wet pond.
According to an infiltration practice survey completed in Maryland, infiltration basins had a
higher failure rate than infiltration trenches or dry wells. Four to six years after construction,
only 38% of the basins (as opposed to 53% of the trenches) functioned as designed. The main
problems with the basins were inappropriate ponding of water and excessive sediment and debris
(Lindsey, 1991).
Infiltration basins that are properly maintained should have a useful life of 25-50 years before
the outlet structure needs to be replaced. However, as indicated above the basin's useful life
may be shortened due to clogging.
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2.1.2 Infiltration Trenches and Dry Wells
Infiltration trenches and dry wells are shallow excavated holes or ditches that have been back-
filled with stone to form an underground reservoir. The two practices are similar except that
dry wells only control small volumes of runoff, such as the runoff from a rooftop. Infiltration
trenches can control several acres of drainage. Infiltration trenches will be discussed in this
section, but the information applies to both infiltration trenches and dry wells.
Runoff is temporarily stored in the trench as it percolates into the soil through the trench's
bottom and sides. Infiltration trenches should drain within 72 hours to maintain aerobic
conditions in order to favor bacteria that aid in pollutant removal and to ensure that the trench
is empty for the next storm (Schueler, 1987). Infiltration trench systems must be designed to
trap coarse sediment before it enters the trench proper and clogs the soil pores. This may be
achieved by using a vegetative filter strip or appropriate upstream inlet design.
Infiltration trenches are typically used for drainage areas less than 5 to 10 acres and may not be
economically practical on larger sites. Trenches are sometimes the only economical practice for
small sites (Schueler, 1987).
There must be at least 4 feet of permeable soil (SCS soil group A or B) between the bottom of
the trench and bedrock or highwater table.
The main factors that influence the removal efficiency are the storage volume, trench surface
area, and soil percolation rates.
Any runoff that percolates into the ground and reaches surface waters through the groundwater
is assumed to have had the pollutants removed by soil processes such as filtration and biological
action. Therefore, any runoff and pollutants that percolate into the ground are assumed to be
removed. The validity of this assumption depends on the pollutants of concern, their chemical
properties and local conditions.
Operation and Maintenance
Routine maintenance requirements include inspecting the basin after every major storm for the
first few months after construction and annually thereafter, mowing the filter strips frequently
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enough to prevent woody growth and removal of sediment from the pre-treatment device.
Despite careful design, construction and maintenance, trenches eventually clog. Studies in
Maryland suggest the longevity of trenches may be 10-15 years (Schueler, 1987).
A survey in Maryland of infiltration devices four to six years after construction found only 53 %
of the infiltration trenches were functioning as designed. The main problems with the trenches
were excessive sediment loads and clogging (Lindsey, 1991).
2.1.3 Vegetative Filter Strip
Vegetative filter strips are similar to grass swales, except that they are only effective for
overland sheet flow. Runoff must be evenly distributed across the filter strip. If the water
concentrates and forms a channel, the filter strip will not perform properly. Level spreading
devices are often used to distribute the runoff evenly across the strip. Vegetated filter strips do
not effectively treat high-velocity flows and therefore are generally recommended for use in
agriculture and low density development and other situations where runoff does not tend to be
concentrated. Also, vegetative filter strips are often used as pretreatment for other structural
practices, such as infiltration basins and infiltration trenches.
Vegetative filter strips should have relatively low slopes, adequate length, and be planted with
erosion resistant plant species. Vegetative filter strips that treat runoff from roads in areas with
freezing winters must contain salt tolerant vegetation. The main factors that influence the
removal efficiency are the vegetation, soil infiltration rate, and flow depth and travel time.
These are dependent on the contributing drainage area, slope of strip, vegetative cover type and
strip length.
Operation and Maintenance
Maintenance requirements for vegetative filter strips are low. The strips should be inspected
frequently the first few months after construction to make sure a dense, vigorous vegetation is
established and the flow does not concentrate. Strips should be inspected annually thereafter.
Usually if natural vegetative succession is allowed to proceed, little other maintenance is
required. Typically, natural succession is the transformation of grass to meadow to second
growth forest and it typically enhances pollutant removal. Short strips are typically maintained
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as lawns and must be mowed 2-3 times a year to suppress weeds and to interrupt natural
succession. Excessive use of pesticides, fertilizers, and other chemicals should be avoided.
Also accumulated sediment must periodically be removed near the top of the strip (Schueler,
1987).
2.1.4 Grassed Swales
Grassed swales are low gradient, conveyance vegetated channels that are used in place of buried
storm drains or curb-and-gutters. To effectively remove pollutants, the swales should have
relatively low slope, adequate length, and be planted with erosion resistant vegetation.
The main factors that influence the removal efficiency are the vegetation, soil infiltration rate,
flow depth, depth to water table and flow travel time. These are dependent on the contributing
drainage area, slope, vegetative cover type and length.
Because swales do not have high pollutant removal rates, they are typically used as part of a
stormwater management/management practice system. Swales can replace curb-and-gutter and
storm sewer systems in low-density residential and recreational areas. Swales have an advantage
over curb-and-gutter and pipes because they can provide pollutant removal, reduce peak flows
and have a lower construction cost. However, swales often lead into storm drain inlets to
prevent the concentrated flows from gullying and eroding the swale during large storms
(Schueler, 1987).
Roadside swales are usually not practical in high density urban areas because each driveway and
road intersection must have a culvert. Swales are also not practical on very flat grades, steep
slopes, or in wet or poorly drained soils (SWRPC, 1991). Grassed swales that treat runoff from
roads in areas with freezing winters must contain salt tolerant vegetation.
Operation and Maintenance
Maintenance requirements are basically the same as normal lawn activities such as mowing,
watering, spot reseeding and weed control. However, maintenance can also cause problems such
as mowing too close to the ground or excessive application of fertilizers.
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The swale should be mowed at least twice each year to stimulate vegetative growth, control
weeds, and maintain the capacity of the system. The grass should never be mowed shorter than
3 to 4 inches (Bassler, Undated).
2.1.5 Porous Pavement
Porous pavement, an alternative to conventional pavement, reduces much of the need for
drainage conveyance and treatment of the runoff from the paved area. Runoff is diverted
through a porous asphalt layer into an underground stone reservoir. Porous pavement has a
layer of porous top course covering an additional layer of gravel. A crushed stone-filled
groundwater recharge bed is typically installed beneath these top layers. Runoff infiltrates
through the porous asphalt layer and into the underground recharge bed. The runoff then
exfiltrates out of the recharge bed into the underlaying soils or into a perforated pipe system.
Porous pavement cannot be used where there is high traffic volume or heavy truck traffic. This
typically restricts porous pavement use to low volume parking areas. Also, porous pavement
is only feasible on sites with gentle slopes.
Porous pavement and recharge beds are usually designed to receive runoff from structures and/or
other paved surfaces through a system of pipes or other conveyance system. However, porous
pavement should not receive runoff from pervious areas, such as lawns. In fact, porous
pavement must be combined with other overall site drainage engineering that carefully directs
any sediment or particulate laden runoff away from porous pavement surfaces (Cahill, 1991).
Also, there must be at least four feet of permeable soil (SCS soil group A or B) between the
bottom of the recharge bed and bedrock or highwater table.
The main factors that influence the removal efficiency are the storage volume, basin surface
area, and soil percolation rates.
Any runoff that percolates into the ground and reaches surface waters through the ground water
is commonly assumed to have had the pollutants removed by soil processes such as filtration and
biological action. Therefore, any runoff and pollutants that percolate into the ground are
estimated as being removed. The validity of this assumption depends on the pollutants of
concern, their chemical properties and local conditions.
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To date, the prime criticism of porous pavement has been its clogging due to sedimentation,
especially during the construction phase but also after-construction (Cahill, 1991). If the
pavement becomes clogged it is difficult and costly to rehabilitate (Schueler, 1987).
A study conducted in Maryland found that of 13 porous pavement sites that had been constructed
four to six years earlier, only 2 facilities were functioning as designed. 77% of the sites had
problems with clogging of the facility and 69% had excessive sediment or debris (Lindsey,
1991). Many states no longer promote the use of porous pavement because it tends to clog with
fine sediments. (Washington Department of Ecology, 1991).
There may also be problems with the use of porous pavement in cold climates since sand, ash,
or deicing salts used for snow removal should never be applied to porous pavement. However,
reports have shown that snow and ice melt more quickly on porous pavement. Porous pavement
is also more susceptible to freeze-thaw damage than conventional pavement (SWRPC, 1991).
Operation and Maintenance
Routine maintenance of porous pavement includes having the surface vacuum swept followed
by high pressure jet hosing at least four times per year to keep the asphalt pores open. In
addition, the site should be inspected after every major storm event for the first few months after
construction and annually thereafter, and potholes and cracks can be replaced using conventional
asphalt if the replaced area does not exceed 10% of the total area. Spot clogging can be treated
by drilling holes into the asphalt layer. However, if the facility becomes completely clogged it
can only be maintained with complete replacement (Schueler, 1987).
2.1.6 Concrete Grid Pavement
Concrete grid pavement, sometimes referred to as "grasscrete," consists of concrete blocks with
regularly interspersed void areas that are filled with pervious materials such as gravel, sand or
grass. The blocks are typically place on a sand and gravel base and designed to provide a load-
bearing surface that is adequate to support vehicles, while allowing infiltration of surface water
into the underlying soil.
As with porous pavement, concrete grid pavement should be used in areas with low traffic
volume. Suggested uses are low volume parking spaces, multi-use open space, fire lanes and
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stream banks/lakeside erosion protection. Concrete grid pavement with grass also require at
least five hours of sunlight daily for most grass species to survive. There must also be at least
four feet of permeable soil (SCS soil group A or B) between the sand and gravel base and
bedrock or high water table.
Concrete grid pavement offers an alternative means in providing load-bearing surfaces without
greatly increasing the amount of impervious areas. The main factor that influences the reduction
in runoff volume and provides pollutants removal are the amount of open spaces, the slope of
the concrete grid pavement; and the underlying soil infiltration rate.
Runoff that percolates into the ground and reaches surface water through the groundwater is
commonly assumed to have had pollutants removed by soil processes such as filtration and
biological action. Therefore, any runoff and pollutants that percolate into the ground are
assumed to be removed. The validity of this assumption depends on the pollutants of concern,
their chemical properties and local conditions.
Operation and Maintenance
Like all infiltration practices, concrete grid pavement requires maintenance to prevent clogging
of the system. In addition, concrete grid pavement with grass requires additional "normal" grass
maintenance, such as mowing, watering and fertilizing. However, extra care should be taken
when applying fertilizers and pesticides that may have an adverse effect on concrete products.
With proper maintenance, the life span of concrete grid pavements can be comparable to that
of asphalt pavements which is 20 years (Smith, 1981).
2.1.7 Filtration Basins and Sand Filters
Filtration basins and sand filters are basins that are lined with a filter media (such as sand and
gravel). Stormwater runoff drains through the filter media and into perforated pipes that are
located in the filter media. Detention time is typically 4 to 6 hours (City of Austin, 1990). The
runoff typically requires some form of preliminary treatment such as sedimentation. Hence,
sediment trapping structures are required for sedimentation to prevent premature clogging of the
filter media.
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Filtration basins have been used for drainage areas from 3 to 80 acres (City of Austin, 1990).
The underdrain pipe system is intended to improve the perculation rate of the soil and/or control
the water table elevation. Consequently, filtration basins may be used on sites with impermeable
soils (SCS soil group C and D) since the runoff filters through specially placed filter media and
pipe system, not native soils. Additionally, a filtration basin's underdrain pipes may lower the
water table in its immediate vicinity, and therefore may be used where water table conditions
would not allow sufficient infiltration (Livingston, 1988).
The main factors that influence the removal rate are the storage volume, filter media, and
detention time.
Operation and Maintenance
Maintenance requirements include inspecting the basin after every major storm for the first few
months after construction and annually thereafter, removing litter and debris and revegetating
eroded areas. The accumulated sediment should also be periodically removed and the filter
media with sediment depositions should be removed and replaced.
2.1.8 Water Quality Inlet - Catch Basin
Catch basins are the simplest form of a water quality inlet. Catch basins are typical single-
chambered stormwater inlets except that the bottom of the structure has been lowered to provide
2 to 4 feet between the outlet pipe and structure bottom. This provides a permanent pool of
water where sedimentation can occur (City of Austin, 1988).
Operation and Maintenance
To perform properly, catch basins must be cleaned and the accumulated sediment removed. The
required frequency of cleaning is dependent on the storage volume and volume of sediment
entering the catch basin. A typical cleaning frequency is approximately 4 times a year.
However, no acceptable clean-out and disposal techniques currently exist (Schueler et al., 1992).
With proper maintenance, a catch basin should have at least a 50-year life span. However, if
the accumulated sediment is not removed it may be resuspended during a storm and actually
increase the pollutant load from an individual storm.
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2.1.9 Water Quality Inlet - Catch Basin with Sand Filter
Catch basins with sand filters are a variation of "one" chamber catch basins. They consist of
two chambers, a sedimentation chamber and filtration chamber that is filled with sand. The
runoff first enters the sedimentation chamber that provides effective removal of coarse particles,
which helps prevent pre-mature clogging of the filter media. It also provides sheet flow into the
filtration chamber that will prevent scouring of filter media (Shaver, 1991). As runoff enters
the filtration chamber, additional pollutant removal of finer suspended solids is achieved through
filtering.
Catch basins with sand filters are typically used in highly impervious areas with drainage areas
less than 5 acres. For larger drainage areas with mixed ground covers filtration basins are used
and function on the same principals. Catch basins with sand filters can also be used to retrofit
small impervious areas that generate high loads.
Operation and Maintenance
Catch basins with sand filters should be annually inspected and periodically the top layer of sand
and deposited sediment should be removed and replaced. The accumulated sediment in the
sedimentation chamber should also be removed periodically (Shaver, 1991). However, no
acceptable clean-out and disposal techniques for the accumulated sediment currently exist
(Schueler et al, 1992).
With proper maintenance and replacement of the sand, the catch basin with sand filter should
have at least a 50-year life span.
2.1.10 Water Quality Inlet - Oil/Grit Separator
Oil/grit separators come in many configurations. A common configuration is the 3-chamber
oil/grit separator. The first chamber is the sedimentation chamber that allows for sedimentation
of coarse material and screening of debris, the second chamber provides separation of oil, grease
and gasoline, and third chamber is provided to prevent any possibility of a surcharge pressure
from occurring and as a safety relief for the structure if a blockage occurs.
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An oil/grit separator should be used in areas receiving high hydrocarbon loadings such as gas
stations, loading areas and parking lots. The maximum drainage area to this type of water
quality inlet is typically one acre. They are also appropriate for retrofit of small areas that
generate high loads of sediment or hydrocarbons such as gas stations and fast food parking lots.
The main factors that influence removal efficiencies are the storage volume for the chambers,
design configuration and maintenance frequency.
Operation and Maintenance
The degree and frequency of maintenance will significantly affect the performance of an oil/grit
separator. Cleaning the oil/grit separators at regular intervals will prevent the accumulated
debris and oil from being discharged from the structure during intense storms. An oil/grit
separator should typically be cleaned at least four times a year. However, no acceptable clean-
out and disposal techniques currently exist (Schueler et al, 1992).
With proper maintenance, the oil/grit separator should have at least a 50-year life span.
However, if the accumulated sediment is not removed it may be resuspended during a storm and
actually increase the pollutant load from an individual storm.
2.1.11 Extended Detention Dry Ponds
Extended detention dry ponds temporarily detain a portion of the runoff after a storm and uses
an outlet device to regulate outflow at a specified rate, that allows the solids time to settle out.
Extended detention dry ponds are typically comprised of two stages: an upper stage that remains
dry except for larger storms, and a lower stage that is designed for typical storms. The pond's
outlet structure is typically sized for water to be detained at least 12 hours, but fully drain within
72 hours.
Extended detention dry ponds are not typically used for drainage areas less than 10 acres
(Schueler, 1987). If the bedrock layer is close to the surface, high excavation costs may make
the extended detention dry pond impractical. In addition, if the water table is within 2 feet of
the bottom of the pond, there may be problems with standing water.
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Extended detention dry ponds cannot typically be used in already developed, heavily urbanized
areas because of space constraints. However, they are a practical means of retrofitting dry
ponds to obtain water quality benefits.
The main factors that influence the removal efficiencies are the storage volume, detention time,
basin shape and degree of maintenance provided.
Operation and Maintenance
Routine maintenance includes mowing, debris/litter removal, inlet and outlet maintenance and
inspection. In addition, nuisance control may be necessary for odors and mosquitos problems
that are caused by occasional standing water and soggy conditions within the lower stage of an
extended detention pond. Non-routine maintenance includes sediment removal. Extended
detention dry ponds are estimated to lose approximately 1 % of their runoff storage capacity per
year due to sediment accumulation. Sediment removal for extended detention dry pond is
therefore recommended every 5-10 years with more frequent spot removals around the outlet
control device (British Columbia Research Corp., 1991).
Under EPA regulations (40 CFR 261) the material that is cleaned out from a detention pond
must be analyzed to determine if it is a hazardous waste. Therefore, a toxicity test should be
done for accumulated sediments removed from ponds. If the sediment fails the test, it is subject
to the Recource Conservation and Recovery Act (RCRA) and must be disposed of at a RCRA
approved facility (Dorman et al, 1989).
With proper maintenance, extended detention dry ponds can have a long useful life. However,
concrete pipes used for outlets often need to be replaced after 50 years.
2.1.12 Dry Ponds
These are basins that are almost always dry except for short periods after large storms. They
are used to control the peak flow rate, which provides erosion control, but they are not effective
for water quality control. However, dry ponds can be retrofitted into extended detention dry
ponds to achieve water quality control.
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Operation and Maintenance
Dry ponds require similar maintenance and have a similar useful life as extended detention dry
ponds.
2.1.13 Wet Ponds
Wet ponds are basins designed to maintain a permanent pool of water and temporarily store
stormwater runoff until it is released from the structure at flow rates less than pre-development
rates. Unlike extended detention wet ponds the stormwater is not stored for an extended period
of time. Enhanced designs include a forebay to trap incoming sediment where it can easily be
removed. A fringe wetland can also be established around the perimeter of the pond.
Wet ponds are not typically used for drainage areas less than 10 acres (Schueler, 1987). Pond
liners are required if the native soils are permeable (SCS soil group A and B) or if there is
fractured bedrock. If the bedrock layer is close to the surface, high excavation costs may make
the wet pond impractical. Wet ponds are not typically used in heavily urbanized areas because
of space constraints.
The main factors that influence the removal efficiencies are permanent pool volume and pond
shape (including inlet and outlet configuration) and degree of maintenance provided.
Operation and Maintenance
Wet ponds require routine maintenance similar to that for extended detention dry ponds. These
ponds can be expected to lose approximately 1 % of their runoff storage capacity per year due
to sediment accumulation. The sediments accumulate out of sight, under the permanent pool.
Therefore, wet ponds require less frequent sediment removal when compared to extended
detention dry ponds. The recommended sediment clean out cycle is about every 10 to 20 years
(British Columbia Research Corp., 1991).
Under EPA regulations (40 CFR 261) the material that is cleaned out from a detention pond
must be analyzed to determine if it is a hazardous waste. Therefore, a toxicity test should be
done for accumulated sediments removed from ponds. If the sediment fails, the test it is subject
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to the Recource Conservation and Recovery Act (RCRA) and must be disposed of at a RCRA
approved facility (Dorman et al, 1989).
With proper maintenance wet ponds should have a long useful life. However, the concrete pipes
used for outlets often need to be replaced after 50 years.
2.1.14 Extended Detention Wet Ponds
Extended detention wet ponds temporarily detain a portion of the runoff after a storm and use
an outlet device to regulate outflow at a specified rate, which allows the solids time to settle out.
Extended detention wet ponds are designed to maintain a permanent pool of water and
temporarily store stormwater runoff for an extended period. The stormwater runoff is typically
detained 12 to 72 hours. Enhanced designs include a forebay to trap incoming sediment where
it can be easily removed- A fringe wetland can also be established around the perimeter of the
pond.
Extended detention wet ponds are not typically used for drainage areas less than 10 acres
(Schueler, 1987). Pond liners are required if the pond soils are permeable (SCS soil group A
and B) or if there is fractured bedrock. If the bedrock layer is close to the surface, high
excavation costs may make the extended detention wet pond not practical. Extended detention
wet ponds are typically not used in heavily urbanized areas because of space constraints.
Extended detention wet ponds are typically more effective than the wet ponds, due to the
increased settling time provided for the stormwater runoff. The main factors that influence the
removal efficiencies are permanent pool volume, pond shape, detention time, and degree of
maintenance provided.
Operation and Maintenance
Extended detention wet ponds require similar maintenance and have a similar useful life as wet
ponds.
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2.1.15 Constructed Stormwater Wetlands
Constructed stormwater wetlands are shallow pools that create growing conditions suitable for
the growth of marsh plants. These stormwater wetlands are designed to maximize pollutant
removal through wetland uptake, retention and settling. Constructed stormwater wetlands are
not usually located within delineated natural wetlands and should be located to have a minimal
impact on surrounding areas. In addition, constructed stormwater wetlands differ from artificial
wetlands created to comply with mitigation requirements in that they do not replicate all the
ecological functions of natural wetlands. (Schueler et al, 1992).
Stormwater wetlands usually fall into one of five basic designs: shallow marsh system,
pond/wetland system, extended detention wetland, pocket wedands, and fringe wetlands.
The main factors that influence the removal efficiency are the size and volume of the wetland
system, flow patterns through the wetland area, the wetlands biota, time of year and degree of
maintenance.
Operation and Maintenance
Constructed stormwater wetlands have maintenance requirements similar to those for wet ponds.
In addition, wetland vegetation should be harvested annually to provide nutrient removal and
prevent flushing of dead vegetation from the wetland during the die-down season (British
Columbia Research Corp., 1991). The useful life span is indefinite.
2.2 EFFECTIVENESS
Summary effectiveness data for the various BMPs are presented in Section 3 of this document.
The following is a discussion of the factors that influence the effectiveness of the various
management practices. Effectiveness is defined as the percent pollutant removal that the practice
achieves if properly designed, constructed and maintained. Regional and site specific factors
such as rainfall amount and duration, vegetation type, soil type and drainage area influence the
effectiveness of a practice and are discussed as appropriate. The data analyzed to draw the
following effectiveness conclusions are presented in Appendix B.
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2.2.1 Infiltration Basins and Infiltration Trenches
Pollutant removal for infiltration devices is achieved by capturing the stormwater runoff and
filtering it through the soils under the devices. The infiltration device effectively removes the
soluble and fine particle pollutants in the captured water. The coarse grained pollutants should
be removed before entering the basin or trench proper to keep it from clogging. The removal
mechanisms of the water infiltrating into the soils involve sorption, precipitation, trapping,
straining and bacterial degradation and transformation. Actual removal rates in the soil will
depend on the solubility and chemistry of the pollutant (Schueler, 1987).
Because there was very little published data on effectiveness of infiltration basins or infiltration
trenches, the efficiencies shown as the probable range in Table 3-2 were calculated using a
method designed by Woodward-Clyde in 1986. The Woodward-Clyde report "Methodology for
Analysis of Detention Basins for Control of Urban Runoff Quality" produced a planning level
estimate for performance of recharge devices based on percolating area, treatment volume, soil
percolation rate and regional rainfall. The report tested the reliability of the results by
comparing removal estimates for a range of conditions with those produced by "STORM" and
"SWMM" models.
To further test the methodology for this report, results were compared to data in the NURP
Final Report (EPA, 1983) for recharge basins in the Great Lake region. The results were
similar. In addition, the methodology results were compared to estimated removal rates in
Controlling Urban Runoff (Schueler, 1987) and they were consistent. Therefore, the
methodology appeared to provide reliable planning level removal rates.
Since there is essentially no difference in the procedure for analyzing infiltration basins and
infiltration trenches, they were analyzed together as recharge devices.
For recharge devices, the percent of pollutant removal is the same as the percent of runoff that
is captured by the. device and infiltrates into the soil. Any runoff that percolates into the ground
and reaches surface waters through the groundwater is commonly assumed to have had the
pollutants removed by soil processes such as filtration and biological action and hence are
ignored by the analysis. Therefore, any runoff and pollutants that percolate into the ground are
assumed to be removed.
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Removal rates are dependent on an available storage volume. For the probable range of
effectiveness shown in Table 3-2, it was assumed that the design volume would equal 90% of
the average runoff volume.
Removal rates are also dependent on rainfall patterns that vary regionally. To account for
regional differences, the model was run for four different rainfall regions. Regional rainfall data
were obtained from "Analysis of Storm Event Characteristics for Selected Rainfall Gages
Throughout the United States" (Woodward-Clyde, 1989). The analysis was performed for four
CZARA regions including the region with the highest volume and intensity and lowest time
between storms (East Gulf), the lowest volume and intensity (Pacific Northwest), the highest
time between storms (Pacific South), and approximate average conditions (Mid-Atlantic).
Another important characteristic for removal efficiency is percolation rates. Infiltration devices
should only be used at locations with permeable soils (SCS soil type A or B). Since the removal
efficiency varies with percolation rate, the efficiency for "A" soils (minimum infiltration rate
2.41 in/hr to 8.27 in/hr) and "B" soils (minimum infiltration rate 0.52 in/hr to 1.02 in/hr)
(Schueler, 1987) are presented separately.
The efficiency is also based on the percolating area. Although as discussed above, the storage
volume was held constant at 90% of the average runoff volume, the percolating area could vary
based on the depth of the pond or trench. The tables assume the minimum depth of a basin is
2 feet and a trench is 3 feet. The maximum depth is 8 feet or the depth that can completely
drain within 72 hours.
To determine the maximum removal efficiencies for the two soil groups, the model was run
using the maximum percolation rate within the soil group and the maximum percolating area
(i.e. minimum depth). The minimum removal rate was based on the minimum percolation rate
and minimum percolating area (i.e. maximum depth).
For the infiltration basin the following was used:
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Minimum
Removal Rate
Maximum
Removal Rate
Soil A 2.4 in/hr perc, 8' height 8.3 in/hr perc, 2' height
Soil B 0.5 in/hr perc, 3' height 1.0 in/hr perc, 2' height
Since the infiltration trench is filed with stone, the available storage space typically equals 40%
the excavation volume (Schueler, 1987). Therefore, the effective height of an 8-foot trench is
8 feet x 40% = 3.2 feet. It is the available storage volume and effective height which are
important when determining the removal efficiency.
Therefore, for the infiltration trench the following was used:
Minimum Maximum
Removal Rate Removal Rate
Soil A 2.4 in/hr perc, 3.2' height 8.3 in/hr perc, 1.2' height
Soil B 0.5 in/hr perc, 3' height 1.0 in/hr perc, 1.2' height
The range of removal rates was estimated based on the runs for the four regions. It was
determined that the regional differences in removal rates were not large enough to justify
reporting removal rates regionally (see Appendix B for model results).
2.2.2 Vegetative Filter Strip
Properly designed and functioning vegetative filter strips effectively remove particulates such as
sediment, organic matter and many trace metals by the filtering action of the grass and
deposition. Removal of soluble pollutants is achieved by infiltration into the soil and is probably
not very effective since only a small portion of the runoff passing through a vegetative filter strip
usually infiltrates. Forested filter strips appear to be more effective than grassed strips, but a
longer length is required for optimal removal rates (Schueler, 1987).
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Several sources of information on urban vegetative filter strips (VFSs) and several on agriculture
VFSs were obtained. Most of the reports gave removal rates for a specific VFS slope and
length. To provide probable removal rates that could be used at the planning level, Table 3-2
was developed from the chart prepared by Dorman et al, 1989 for the Federal Highway
Administration (FWHA).
The FHWA report (Dorman et al, 1989) is based on research and monitoring done for highways.
However, the removal mechanisms and rates of VFSs should be the same on highway sites as
on urban sites and therefore are applicable. The depth of flow in the VFS was assumed to be
less than 4 inches to estimate removal rates that could be provided from properly designed urban
VFSs using the chart prepared by Dorman et al, 1989. This would be appropriate for almost
all VFSs since they are designed for sheet flow and not concentrated flow. The travel time was
assumed to be greater than 5 minutes, which also should be appropriate for correctly designed
VFSs, since the strip should have a low slope and adequate length.
The total suspended solids (TSS) removal efficiency range was read from the chart. In addition,
the research indicated that the lead removal rate is approximately 90% of the TSS removal rate
and zinc removal is approximately 60% of TSS.
These removal efficiency ranges are similar to reported ranges in other references. The report
indicated that total phosphorous (TP) and total nitrogen (TN) removal rates could not be easily
related to depth of flow and travel time. Therefore, TP and TN removal rates for Table 3-2
were taken as the range from the other references, excluding turf strips.
It must be noted that the cited removal rates are based on ideal conditions - evenly distributed
sheet flow and a dense, vigorous vegetative cover. However, if the water concentrates, removal
rates can be significantly less and if eroded gullies form the vegetative filter strip could actually
be a source of sediment.
2.2.3 Grassed Swales
Properly designed and functioning grassed swales provide some pollutant removal through
filtering by vegetation of particulate pollutants, biological update of nutrients and infiltration of
runoff. However, because the flow is concentrated the removal rates are low (SWRPC, 1991).
Swales are not generally effective in removing soluble pollutants. Also, in some cases trace
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metals have leached from swale culverts and nutrients have leached from fertilizers.
Consequently, these pollutant concentrations have actually increased (Schueler, 1987).
Several sources of information on grassed swales were reviewed. However the reported percent
removal for TSS varied from 0 to >99%. These differences are most likely due to differences
in the swale length and slope. Since swales in urban areas are typically short in length, the high
removal rates are probably not possible. However, if properly designed, a swale with a low
slope should achieve some pollutant removal.
2.2.4 Porous Pavement
Two porous pavement studies were cited in the literature. They both obtained relatively high
pollutant removal rates. However, as stated previously, a Maryland study found that of 13
porous pavement sites that had been constructed 4 to 6 years earlier, only 2 facilities were
functioning as designed. Several of the sites evaluated failed due to clogging of the surface from
sediment during and following construction, as a result of sediment-laden runoff being conveyed
to the porous pavement surface.
2.2.5 Concrete Grid Pavement
The information on the removal efficiencies of concrete grid pavements is obtained from
laboratory studies by Day, et.al., 1981 and monitoring studies for a parking lot in downtown
Dayton, Ohio by Smith, et.al., 1981.
The laboratory studies by Day provide information on the runoff volume and pollutant load
reductions associated with concrete grid pavements. The monitoring studies by Smith provide
the removal efficiencies of concrete grid pavements as the reductions in pollutant concentration
and mass in water that has percolated through the concrete grid pavements. For the purpose of
this report, the pollutant removal efficiencies of the concrete grid pavement presented from both
studies shall be interpreted as the reduction in runoff volume. Any runoff that percolates into
the ground and reaches surface waters through the groundwater is assumed to have had the
pollutants removed by soil processes such as filtration and biological action. Therefore, the
removal efficiencies of pollutant is assumed to be the reduction in runoff.
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Concrete grid pavements are basically a form of infiltration measures. Therefore, as a
reference, their pollutant removal efficiencies should be similar to that of porous pavements.
2.2.6 Filtration Basin
Removal efficiencies for filtration basins were obtained primarily from two sources: laboratory
studies done in 1981 (Wanielista et al, 1981 cited in City of Austin, 1988) and monitoring
studies done on several filtration basins in Austin, Texas, 1990.
The Austin report contained the monitoring results for several basins and estimated expected
removal rates for several possible designs based on the monitoring results. Three of the designs
were chosen as appropriate for this category and are off-line sedimentation/filtration basin, on-
line sand/sod filtration basin, and on-line sand basin. The expected removal rates are consistent
with the monitoring study results and laboratory study. Therefore, the range of probable
removal rates given in Table 3-2 are the same as the expected removal rates presented in the
Austin Report, with two exceptions. The highest expected removal rate for TSS is 100%.
However, during large storms some of the runoff will not be treated, and 100% removal does
not seem realistic. Consequently, the high range of TSS removal was reduced to 90% for Table
3-2. In addition, the expected removal rates do not include COD, so the COD removal rates
reported from the monitoring study were used.
2.2.7 Water Quality Inlet - Catch Basin
There are very little data available regarding the effectiveness of water quality inlets. The
configurations of outlet pipe and the permanent pool for sedimentation allow the catch basins to
function as small sediment basins with short detention time and high degree of turbulence.
Catch basins appear to trap only coarse-grained sediments.
2.2.8 Water Quality Inlet - Catch Basin with Sand Filter
The effectiveness of catch basins with sand filter are estimated to be similar to filtration basins.
However, there are no available monitoring studies for catch basins with sand filters. The
effectiveness of the sediment chamber for removal of the different size particles depends on the
particle's setting velocity and the chamber's length and depth. The effectiveness of the filtration
media depends on the depth of the filter media.
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2.2.9 Water Quality Inlet - Oil/Grit Separator
The pollutant removal of an oil/grit separator has not been widely tested in the field. Removal
efficiencies for oil/grit separators were obtained from two references. These references
indicated that oil/grit separators have marginal TSS removal efficiency, i.e., less than 25%.
These removal efficiencies are general estimates that inferred from studies on similar structures
such as catch basins. There were no specific oil and grease removal efficiencies provided for
oil/grit separators but oil and grease removal can be improved with the aid of adsorbent
(Silverman et al., 1988). One such application is to place the adsorbent in a removable fine
mesh bag; replacement of the adsorbent could be accomplished by replacing the exhausted bag
with one containing fresh adsorbent.
2.2.10 Extended Detention Dry Pond
Seven sets of information on removal efficiencies for extended detention dry ponds were
available in Schueler et al, 1992. The removal efficiency of TSS fell into two distinct ranges.
Four ponds' removal efficiencies were from 3% to 30%, and three ponds' removal efficiencies
were from 70% to 87%. All of the ponds in the lower range had short detention times (under
10 hours). Settling column experiments have shown that most settling of suspended pollutants
occurs within the first 12 hours (OWML, 1983 cited in Schueler, 1987). Therefore, extended
detention ponds should provide a minimum of 12 hours detention. Using this criteria, the 4
ponds with the low detention times were determined to have insufficient detention time and
therefore discounted for determining the probable range of effectiveness for properly designed
and maintained extended detention dry ponds. The removal efficiencies for the remaining three
ponds were used to determine the probable range of removal for extended detention dry ponds.
2.2.11 Wet Pond
Twenty-four sets of information on wet ponds' removal efficiencies were available in Schueler
et al, 1992. Current literature indicates that removal efficiency should increase with increased
treatment volume. However, plotting the treatment volume (inch per drainage acre) versus
removal efficiency did not show this for the ponds. This is probably due to many site specific
variables. Of the twenty-four, three had reported TSS removal efficiency of <32% while
twenty-one had TSS removal efficiency >54%. The three ponds with substantially lower
reported removal rates may be due to difference in calculation methods (pond #25) and the
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storage volume being considerably less (ponds #9 and #10). Since these three ponds' removal
efficiencies were substantially different for most pollutants, they were discounted for determining
the probable removal rate of a properly designed and maintained wet pond. The probable
removal rates given in Table 3-2 show the range of the remaining efficiencies.
2.2.12 Extended Detention Wet Pond
Data on removal efficiencies for three extended detention wet ponds were available in Schueler,
1992. Table 3-2 shows the range of efficiencies for TSS and TP from the raw data. As
expected, the TSS and TP removal efficiency for the extended wet pond were higher than for
the wet pond. However, there was not sufficient information on the remaining pollutants to
come to a similar conclusion. However, the extended detention wet pond probably provides
higher removal rates for all pollutants due to the increased detention time (which allows
additional settling) and the additional aquatic fringe (which provides increased biological uptake).
2.2.13 Constructed Stormwater Wetlands
The pollutant removal performance of nearly twenty stormwater wetland systems were reported
in Woodward-Clyde, 1991. The probable range of removal effectiveness in Table 3-2 is for the
designs with a minimum area of wetland equal to 1% of the drainage area. Although the
stormwater wetland systems monitored have differed greatly in their design and treatment
volume, most have shown moderate to excellent pollutant removal capability under a range of
environmental conditions (Schueler et al, 1992).
Stormwater wetlands pollutant removal capability is comparable to that of wet ponds. Sediment
removal may be greater in well designed stormwater wetlands, but phosphorous removal is more
variable.
2.3 COST
The cost of the management practices varies greatly and is dependent upon many factors such
as availability and proximity of materials, time of year and labor rates. The costs presented in
this document are a summary of costs found in published documents. These costs are presented
to give planners an idea of the cost of a practice relative to another and are not recommended
for use in estimating or bidding construction contracts. Local suppliers and contractors could
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be contacted for this purpose. Cost data were generally influenced more by proximity to major
urban centers rather than regionally. Consequently, regional variation of cost could not be
supported by the data obtained. It may be more effective to consider the cost ranges presented
as "national" averages and to adjust the cost on a regional basis using published regional cost
variation indexes (e.g., the regional cost index published by the Engineering News Record).
Quantitative cost data are discussed in Section 3.0 and presented in Table 3-3. Table 3-3
summarizes the total annual cost, including the annualized construction cost. To annualize this
cost an interest rate of 5 % was assumed. The cost data used to develop these cost summaries
are presented in the Appendix.
The costs presented are only construction costs. It does not include the cost of such items as
land, engineering, and review fees.
The cost of the management practices are dependant on the treatment volume. Due to economy
of scale, as the treatment volume increases, the cost per cubic foot of water treated decreases.
Ponds tend to be the most economical practice for larger drainage areas. Infiltration trenches
and water quality inlets are typically only cost effective for relatively small drainage areas.
Vegetative controls are relatively inexpensive. In fact, grassed swales are less expensive to
construct than curb-and-gutter.
The following is a discussion of the factors that influence the costs that can be expected in
implementing various management practices.
2.3.1 Infiltration Basins
The cost of infiltration basins is directly related to the storage volume. Due to economy of
scale, as storage volume increases, cost per unit volume decreases. Infiltration basins are
typically cheaper per unit volume than extended detention dry ponds due to decreased cost of
the outlet structure. Infiltration basins are also cheaper on a per volume basis than infiltration
trenches.
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2.3.2 Infiltration Trenches
The cost of infiltration trenches is directly related to storage volume. As the storage volume
increases, cost per unit volume decreases. Schueler, 1987 indicates that infiltration trenches may
not be economically practical on sites larger than 5 to 10 acres.
2.3.3 Vegetative Filter Strip
The cost of a VFS is dependent on the type of vegetation used in the strip. If the natural
vegetation is maintained, the cost is minimal.
Generally an area that will serve as a VFS should not be cleared and graded, since it is more
effective if the natural vegetation is maintained. A VFS should only be seeded or sodded if the
area is disturbed for the associated development, otherwise it should remain undisturbed.
Therefore the cost of VFS is assumed only to include the cost for sod or seed and any cost for
clearing and grading is a cost associated with site development and not installation of the
practice.
2.3.4 Grassed Swale
The cost of a grassed swale will vary depending upon the geometry of the swale (height and
width) and method of establishing the vegetation (seed or sod). The construction cost of grassed
swales are typically less than curb-and-gutter. However, the maintenance cost of swales is
generally higher than curb-and-gutter.
2.3.5 Porous Pavement
The cost of porous pavement should be measured as the incremental cost, or the cost beyond that
required for conventional asphalt pavement. However, to determine the full value of porous
pavement one should also consider the savings from reducing land consumption and eliminating
storm systems, e.g. curbs, inlets and pipes (Cahill, 1991). Also, one must consider the
additional cost of directing pervious area runoff around porous pavement.
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2.3.6 Concrete Grid Pavement
The cost per square foot of concrete grid pavements will vary depending on the types and
specifications of concrete grid pavements and the existing underlying soil conditions. Currently,
there are no ASTM standards specification governing properties of concrete grid pavement units.
However, the National Concrete Masonry Association (NCMA) has published an industry
standard specification for concrete grid pavers designated as A-15-82.
In addition to the initial installation cost, there will be maintenance costs such as grass mowing,
fertilizing and reseeding. The cost of concrete grid pavement is presented as the incremental
cost, i.e., cost beyond that required of conventional asphalt pavement. The incremental cost of
maintenance for concrete pavement shows a net decrease from that of asphalt pavement. When
comparing the maintenance cost between concrete grid and asphalt pavements, concrete grid
pavement does not require the minimum one overlay that is assumed necessary during the 20
year lifespan of asphalt pavement.
The concrete grid pavement installed in place and annual maintenance cost presented in Table
3-3 is based on information provided by NCMA.
2.3.7 Filtration Basin
Data regarding the costs of filtration basins were obtained from engineers' estimates done in
Austin, Texas for various sized basins (Tull, 1990). These reported costs per cubic foot of
storage are higher than reported costs for infiltration devises, dry extended detention ponds or
wet ponds. No information was available regarding the maintenance costs of filtration basins.
However, because filtration basins function similar to infiltration basins, the annual operation
and maintenance cost was assumed to be the same percent of capital cost as infiltration basins.
2.3.8 Water Quality Inlet - Catch Basin
In general, the cost of catch basins will be similar to those for standard precast inlets. The
annual maintenance cost of cleaning catch basins will depend on the number of times per year
they are cleaned and the method used. Cleaning catch basins manually by hand or with
clamshell buckets costs approximately twice as much as cleaning with a vacuum attachment to
a sweeper (SWRPC, 1991).
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2.3.9 Water Quality Inlet - Catch Basin with Sand Filter
The cost of a catch basin with sand filter will depend on the size of the sedimentation and
filtration chambers, which depends on the drainage area. No information was available
regarding the maintenance cost of catch basins with sand filters. However, information was
available on the maintenance cost of oil/grit separators. It was estimated that the maintenance
cost of catch basins with sand filters would be higher than oil/grit separators since the sand filter
must be periodically replaced. Please note that although maintenance costs of catch basins were
available, they could not be used since they are reported in a different unit than catch basins with
sand filters (each verse drainage acre).
2.3.10 Water Quality Inlet - Oil/Grit Separator
The cost of the oil/grit separator will depend on the storage volume of the chambers, which in
turn depends on the drainage area and the configuration of the design components.
The annual cost of maintenance of oil/grit separators will depend on the number of times per
year they are cleaned and the method used. The maintenance costs were assumed to be the same
as cleaning catch basins.
2.3.11 Extended Detention Dry Pond
The cost of ponds is directly related to the storage volume. In addition, if the bedrock layer is
close to the surface, high excavation costs may make extended detention dry ponds impractical.
The cost of dry ponds were obtained from four sources. In addition, Chart 4, in Appendix C,
shows the economy of scale for extended detention dry ponds.
2.3.12 Wet Pond
The cost of ponds is directly related to the storage volume. In addition, if the bedrock layer is
close to the surface the cost may increase exponentially.
The costs of wet ponds were obtained from four sources. The wide cost differences shown on
the wet pond cost chart is probably due to the less expensive ponds being constructed in natural
low lying areas where little or no excavation was required. However, these low lying areas are
80040000H:\WP\finaI\postcon\chap2
2-27
Woodward-Clyde
January 28, 1993
-------
often wetlands, and due to present-day strict wetlands laws, these low costs may not be realistic
in 1991.
2.3.13 Extended Detention Wet Pond
The cost of an extended detention wet pond should be similar to the wet pond. The main cost
difference would be the outlet structure for the extended detention pond would need to be
designed to temporarily store the stormwater runoff.
There was no information available for extended detention wet pond costs, but in some cases the
cost difference between wet ponds and extended detention wet ponds will be minimal.
Therefore, it was assumed that wet ponds and extended detention wet ponds have the same cost.
2.3.14 Constructed Stormwater Wetlands
Construction costs for stormwater wetlands have not been systematically analyzed, but are
expected to be marginally higher than wet ponds due to the more complex grading and wetland
planting costs. Maintenance costs may average between three and five percent of construction
costs annually (Schueler et al, 1992).
80040000H:\WP\final\postcon\chap2
2-28
Woodward-Clyde
January 28, 1993
-------
3.0
SUMMARY TABLES
This section presents summary effectiveness and cost tables (Table 3-1, 3-2, and 3-3) for the
various management practices discussed in this document. These summary tables are based on
the detailed cost and effectiveness data presented in the Appendix. It should be noted that only
practices that had enough quantitative data on which to base conclusions are presented in the
tables.
Table 3-1 summarizes the advantages and disadvantages of the various management practices.
Table 3-2 summarizes the effectiveness of the various management practices. Effectiveness was
defined as the percent pollutant removal that the practice achieves if properly designed,
constructed and maintained. There are many pollutants found in urban runoff and the
effectiveness can be measured for each of the pollutants. Researchers have not come to a
consensus as to what pollutants are the best to use for measuring effectiveness. However, the
pollutants that appear to be of most concern are Total Suspend Solids (TSS), Total Phosphorus
(TP), Total Nitrogen (TN), Chemical Oxygen Demand (COD), Lead (Pb), and Zinc (Zn).
Therefore, management practices' effectiveness for these pollutants are tabulated in Table 3-2.
Pollutant removal is achieved through complex chemical, biological, and physical processes.
Due to the complexity of the processes and their dependence on a large variety of parameters,
researchers have not come to a consensus as to the effectiveness of the practices. Therefore,
Table 3-2 presents the effectiveness information and includes the average and range observed
in the reviewed literature, the probable range expected from a properly designed and maintained
practice (based on the literature and issues discussed in Section 2.2), and the number of
references considered in developing these data.
During the literature search for this project, it was apparent that there have been a limited
number of monitoring studies completed regarding the effectiveness of these management
practices. The results of the studies that were available are summarized in Table 3-1. However,
performance monitoring studies are difficult to compare due to the differences in the studies.
The following variables are involved in BMP performance monitoring (Schueler, 1992):
• Number of storms monitored;
• Type and size of storm monitored;
80040000H:\wp\final\postcon\chap3
3-1
Woodward-Clyde
January 28, 1993
-------
• BMP design variations;
• Monitoring technique used;
• Pollutant removal calculation technique used;
• Seasons monitored; and
• Characteristics of contributing watershed.
It is also difficult to quantify the pollutant removal capabilities of a BMP because the
performance varies from storm to storm. The pollutant removal capabilities of a BMP will also
vary during the BMP's lifetime (Schueler, 1992).
Table 3-3 presents construction and annual maintenance cost information. The cost information
in this table is annualized so that comparisons can be made from one practice to another. The
annualized cost was determined by assuming an interest rate of 5 %. Some practices have limited
useful lives. However, other practices will continue to provide water quality benefits indefinitely
if properly maintained. To annualize the capital costs of those practices, they were assumed to
have an useful life of 50 years. These costs are presented to give planners an idea of the cost
of practice relative to another and are not recommended for use in estimating or bidding
construction contracts.
80040000H:\wp\final\postcon\chap3
3-2
Woodward-Clyde
January 28, 1993
-------
TABLE 3-1. ADVANTAGES AND DISADVANTAGES OF MANAGEMENT PRACTICES1
MANAGEMENT
PRACTICE
ADVANTAGE
DISADVANTAGE
Infiltration Basin
• Provides groundwater recharge
• Can serve large developments
• High removal capability for particulate pollutants and moderate
removal for soluble pollutants
• When basin works, it can replicate predevelopment hydrology
more closely than other BMP options
• Basins provide more habitat value than other infiltration systems
• Possible risk of contaminating groundwater
• Only feasible where 9oils permeable and have sufficient
depth to rock and water table
• Fairly high failure rate
• If not adequately maintained can be eyesore, breed mosquitos
and create undesirable odors
• Regular maintenance activities cannot prevent rapid clogging
of infiltration basins
Infiltration Trench
• Provides groundwater recharge
• Can serve small drainage areas
• Can fit into medians, perimeters and other unutilized areas of a
development site
• Helps replicate predevelopment hydrology, increases dry
weather baselfow, and reduces bankfull flooding frequency
• Possible risk of contaminating groundwater
• Only feasible where soils permeable and have sufficient
depth to rock and water table
• Since not as visible as other BMPs, less likely to be
maintained by residents
• Requires significant maintenance
Vegetative Filter Strip (VFS)
• Low maintenance requirements
• Can be used as part of the runoff conveyance system to provide
pre-treatment
• Can effectively reduce particulate pollutant levels in areas where
runoff velocity is low to moderate
• Promotes groundwater recharge, urban wildlife habitat, and
stream bank stabilization
• Economical
* Often concentrates water, which significantly reduces
effectiveness
* Ability to remove soluble pollutants highly variable
* Limited feasibility in highly urbanized areas where runoff
velocities are high and flow is concentrated
* Requires periodic repair, regrading, and sediment removal to
prevent channelization
Grassed Swale
• Requires minimal land area
• Can be used as part of the runoff conveyance system to provide
pretreatment
• Can provide sufficient runoff control to replace curb and gutter
in single-family residential subdivisions and on highway
medians
• Economical
• Low slope swales can create wetland habitat
* Low pollutant removal rates
* Leaching from culverts and fertilized lawns may actually
increase the presence of trace metals and nutrients
* Requires more land than curb and gutter
* Can impact on groudwater quality in certain situations
-------
TABLE 3-1 ADVANTAGES AND DISADVANTAGES OF MANAGEMENT PRACTICES1 (continued)
MANAGEMENT
PRACTICE
ADVANTAGE
DISADVANTAGE
Porous Pavement
• Provides groundwater recharge
• Provides water quality control without additional consumption
of land
• Can provide peak flow control
• High removal rates for sediment, nutrients, organic matter, and
trace metals
• When operating properly can replicate predevelopment
hydrology
• Eliminates the need for stormwater drainage, conveyance, and
treatment systems off-site
• Requires regular maintenance
• Possible risk of contaminating groundwater
• Only feasible where soil is permeable, there is sufficient
depth to rock and water table, and there are gentle slopes
• Not suitable for areas with high traffic volume
• Need extensive feasibility tests, inspections, and very high
level of construction workmanship (Schueler, 1987)
• High failure rate due to clogging
• Not suitable to serve large off-site pervious areas
Concrete Grid Pavement
• Can provide peak flow control
• Provides groundwater recharge
• Provides water quality control without additional consumption
of land
• Requires regular maintenance
• Not suitable for area with high traffic volume
• Possible risk of contaminating groundwater
• Only feasible where soil is permeable, there is sufficient
depth to rock and water table, and there are gentle Blopes
Sand Filter/Filtration Basin
• Ability to accommodate medium size development (3-80 acres)
• Flexibility to provide or not provide groundwater recharge
• Can provide peak volume control
• Can be used in areas where groundater quality concerns
precludes the use of infiltration
• Requires pretreatment of stormwater through sedimentation
to prevent filter media from premature clogging
• Larger designs without grass covers may not be attractive in
residential areas
• Do not provide significant stormwater detention for
downstreams areas
Water Quality Inlets
• Provides high degree of removal efficiencies for larger particles
and debris as pre-treatment
• Requires minimal land area
• Flexibility to retrofit existing small drainage areas and
applicable to most urban areas
• Not feasible for drainage area greater than 1 acre
• Marginal removal of small particles, heavy metals and
organic pollutants
• Not effective as water quality control for intense storms
• Minimal nutrient removal
Water Quality Inlet
with Sand Filter
• Provides high removal efficiencies on particulates
• Requires minimal land area
• Flexibility to retrofit existing small drainage areas
• Higher removal of nutrient as compared to catch basins and
oil/grit separator
* Not feasible for drainage area greater than 5 acres
* Only feasible for areas that are stabilized and highly
impervious
* Not effective as water quality control for intense storms
-------
00
TABLE 3-1 ADVANTAGES AND DISADVANTAGES OF MANAGEMENT PRACTICES1 (continued)
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MANAGEMENT
PRACTICE
ADVANTAGE
DISADVANTAGE
Oil/Grit Separator
• Captures coarse-grained sediments and some hydrocarbons
• Requires minimal land area
• Flexibility to retrofit existing small drainage areas and
applicable to most urban areas
• Shows some capacity to trap trash, debris, and other floatables
• Can be adapted to all regions of the country
* Not feasible for drainage area greater than 1 acre
* Minimal nutrient and organic matter removal
• Not effective as water quality control for intense storms
• Concern exists over the pollutant toxicity of tapped residuals
• Require high maintenance
* Pulse hydrocarbon loads may result from resuspension
during large storms
Extended Detention
Dry Pond
• Can provide peak flow control
• Possible to provide good particulates removal
• Can serve large development
• Requires less capital cost and land area when compared to wet
pond
• Does not generally release warm or anoxic water downstream
• Provides excellent protection for downstream channel erosion
• Can create valuable wetland and meadow habitat when properly
landscaped
* Removal rates for soluble pollutants are quite low
* Not economical for drainage areas less than 10 acres
* If not adequately maintained can be eyesore, breed mosquitos
and create undesirable odors
Wet Pond
• Can provide peak flow control
• Can serve large developments, most cost effective for larger
more intensively developed sites
• Enhance aesthetic and provide recreational benefits
• Little groundwater discharge
• Permanent pool in wet ponds helps to prevent scour and
resuspension of sediments
• Provides moderate to high removal of both paniculate and
soluble urban stormwater pollutants
• Creates wildlife habitat
• Very useful in both low and high visibility commercial and
residential development
• Not economical for drainage area less than 10 acres
• Potential safety hazards if not properly maintained
• If not adequately maintained can be eyesore, breed mosquitos
and create undesirable odors
• Requires considerable space which limits their use in densely
urbanized areas with expensive land and property values
• Not suitable for hydrologic soil group "A" and "B" (SCS
classification)
• With possible thermal discharge and oxygen depletion, may
severely impact downstream aquatic life
Extended Detention
Wet Pond
• Can provide peak flow control
• Can serve large developments, most cost effective for larger
more intensively developed sites
• Enhance aesthetic and provide recreational benefits
• Permanent pool in wet ponds helps to prevent scour and
resuspension of sediments
• Provide better nutrient removal when compared to wet pond
• Creates wildlife habitat
• Not economical for drainage area less than 10 acres
• Potential safety hazards if not properly maintained
• If not adequately maintained can be eyesore, breed mosquitos
and create undesirable odors
• Requires considerable space which limits their use in densely
urbanized areas with expensive land and properly values
• Not suitable for hydrologic soil group "A" and "B" (SCS
classification)
• With possible thermal discharge and oxygen depletion, may
severely impact downstream aquatic life
-------
TABLE 3-1 ADVANTAGES AND DISADVANTAGES OF MANAGEMENT PRACTICES1 (continued)
MANAGEMENT
PRACTICE
ADVANTAGE
DISADVANTAGE
Constructed Stormwater Wetland
• Can serve large developments, most cost effective for larger
more intensively developed sites
• Provides peak flow control
• Enhance aesthetic and provide recreational benefits
• The marsh fringe also protects shoreline from erosion
• Permanent pool in wet ponds helps to prevent scour and
resuspension of sediments
• Has high pollutant removal capability
• Creates wildlife habitat
• Not economical for drainage area less than 10 acres
• Potential safety hazards if not properly maintained
• If not adequately maintained can be eyesore, breed mosquitos
and create undesirable odors
• Requires considerable space which limits their use in densely
urbanized areas with expensive land and property values
• With possible thermal discharge and oxygen depletion may
severely impact downstream aquatic life
• May contribute to nutrient loadings during die-down periods
of vegetations
!Several items taken from Schucher et al, 1992.
-------
TABLE 3-2 EFFECTIVENESS OF MANAGEMENT PRACTICES FOR CONTROL OF RUNOFF FROM NEWLY DEVELOPED AREAS
MANAGEMENT
% REMOVAL
MAIN
REFERENCES
PRACTICE
REMOVAL
TSS
TP
TN
COD
Pb
Zn
EFFICIENCY
FACTORS
INFILTRATION BASIN: Ave:
75
65
60
65
65
65
• Soil
Schueler, 1987; EPA, 1983;
percolation
Woodward-Clyde, 1986
Reported Range:
45-100
45-100
45-100
45-100
45-100
45-100
rates
* Basin surface
Probable Range (1):
area
• Storage
SCS Soil Group A
60-100
60-100
60-100
60-100
60-100
60-100
Volume
SCS Soil Group B
50-80
50-80
50-80
50-80
50-80
50-80
No. Values Considered:
7
7
7
4
4
4
INFILTRATION Ave:
75
60
55
65
65
65
• Soil
Schueler, 1987; EPA, 1983;
TRENCH:
percolation
Woodward-Clyde, 1986; Kuo,
Reported Range:
45-100
40-100
(-10)-100
45-100
45-100
45-100
rates
et al, 1988; Lugbill, 1990
• T rench
Probable Range (2):
surface area
• Storage
SCS Soil Group A
60-100
60-100
60-100
60-100
60-100
60-100
Volume
SCS Soil Group B
50-90
50-90
50-90
50-90
50-90
50-90
No. Values Considered:
9
9
9
4
4
4
VEGETATIVE FILTER Ave:
65
40
40
40
45
60
• Runoff
IEP, 1991; Casman, 1990;
STRIP
volume
Glick, et al, 1991; VA Dept.
Reported Range:
20-80
0-95
0-70
0-80
20-90*
30-90**
• Slope
of Cons., 1987; Minnesota
• Soil
PCA, 1989; Schuler, 1987;
Probable Range (3):
40-90
30-80
20-60
-
30-80
20-50
infiltration
Hartigan, et al, 1989
rates
No. Values Considered:
7
A
3
2
3
3
• Vegetative
cover
• Buffer length
-------
TABLE 3-2 EFFECTIVENESS OF MANAGEMENT PRACTICES FOR CONTROL OF RUNOFF FROM NEWLY DEVELOPED AREAS (Continued)
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MANAGEMENT
% REMOVAL
MAIN
REFERENCES
PRACTICE
REMOVAL
TSS
TP
TN
COD
Pb
Zn
EFFICIENCY
FACTORS
GRASSED SWALES Ave:
60
20
10
25
70
60
• Runoff
Yousef, et al, 1985; Dupuis,
Volume
1985; Washington State,
Reported Range:
0-100
0-100
0-40
25
3-100*
50-60*
• Slope
1988; Schueler, 1987; British
• Soil
Columbia Res. Corp., 1991;
Probable Range (4):
20-40
20-40
10-30
-
10-20
10-20
infiltration
EPA, 1983; Whalen, et al,
rates
1988; Pitt, 1986; Casman,
No. Values Considered:
10
8
4
1
10
7
• Vegetative
1990
cover
* Swale length
• Swale
geometry
POROUS PAVEMENT Ave:
90
65
85
80
100
100
• Percolation
Schueler, 1987
rates
Reported Range:
80-95
65
80-85
80
100
100
• Storage
volume
Probable Range:
60-90
60-90
60-90
60-90
60-90
60-90
No. Values Considered:
2
2
2
2
2
2
CONCRETE GRID Ave:
90
90
90
90
90
90
• Percolation
Day, 1981; Smith, et al, 1981
PAVEMENT
rates
Reported Range:
65-100
65-100
65-100
65-100
65-100
65-100
Probable Range:
60-90
60-90
60-90
60-90
60-90
60-90
No. Values Considered:
2
2
2
2
2
2
SAND Ave:
80
50
35
55
60
65
• Treatment
City of Austin, 1988;
FILTER/FILTRATION
volume
City of Austin, 1990
BASIN Reported Range:
60-95
0-90
20-40
45-70
30-90
50-80
• Filtration
media
Probable Range:
60-90
0-80
20-40
40-70
40-80
40-80
No. Values Considered:
10
6
7
3
5
5
-------
TABLE 3-2 EFFECTIVENESS OF MANAGEMENT PRACTICES FOR CONTROL OF RUNOFF FROM NEWLY DEVELOPED AREAS (Continued)
MANAGEMENT
% REMOVAL
MAIN
REFERENCES
PRACTICE
REMOVAL
TSS
TP
TN
COD
Pb
Zn
EFFICIENCY
FACTORS
WATER QUALITY
Ave:
35
5
20
5
15
5
• Maintenance
Pitt, 1986; Field, 1985;
INLET (7)
Schueler, 1987
Reported Range:
0-95
5-10
5-55
5-10
10-25
5-10
• Sedimentation
storage
Probable Range:
10-25
5-10
5-10
5-10
10-25
5-10
volume
No. Values Considered:
3
1
2
I
2
1
WATER QUALITY
Ave:
80
NA
35
55
80
65
• Sedimentation
Shaver, 1991
INLET WITH SAND
storage
FILTER (7)
Reported Range:
75-85
NA
30-45
45-70
70-90
50-S0
volume
Probable Range:
70-90
30-40
40-70
70-90
50-80
• Depth of filter
media
No. Values Considered:
1
0
1
1
1
1
OILVGRIT SEPARATOR
Ave:
15
5
5
5
15
5
• Sedimentation
Schueler, 1987
(7)
storage
Reported Range:
0-25
5-10
5-10
5-10
10-25
5-10
volume
Probable Range:
10-25
5-10
5-10
5-10
10-25
5-10
• Outlet
configurations
Number of References
2
1
1
1
1
1
EXTENDED
Ave:
45
25
30
20
50
20
• Storage
MWCOG, 1983; City of
DETENTION
volume
Austin, 1991; Schueler and
DRY POND
Reported Range:
5-90
10-55
20-60
0-40
25-65
(-40)-65
• Detention
Helfrich, 1988; Pope and
time
Hess, 1988; OWML, 1987;
Probable Range (5) :
70-90
10-60
20-60
30-40
20-60
40-60
• Pond shape
Bait. Dept. P.W., 1989, cited
in Schueler el al, 1992
No. Values Considered:
6
6
4
5
4
5
-------
00
TABLE 3-2 EFFECTIVENESS OF MANAGEMENT PRACTICES FOR CONTROL OF RUNOFF FROM NEWLY DEVELOPED AREAS (Continued)
MANAGEMENT
% REMOVAL
MAIN
REFERENCES
PRACTICE
REMOVAL
TSS
TP
TN
COD
Pb
Zn
EFFICIENCY
FACTORS
WET POND Ave:
70
50
35
50
70
60
• Pool volume
Wotzka and Oberta, 1988;
• Pond shape
Yousefet al, 1986;Cullum,
Reported Range:
(-35)-99
10-90
5-85
5-90
10-95
10-95
1985; Driscoll, 1983;
Driscoll, 1986; OWML,
Probable Range:
50-99
20-90
10-90
10-90
10-95
20-95
1983; Wu, et al, 1988;
Holler, 1987; Martin, 1988;
No. Values Considered:
24
23
11
11
20
17
Dorman, et al, 1989; City of
Austin, 1990; Horner et al,
1990, Oberts et al, 1989,
Bannerman, 1992, cited in
Schueler et al, 1992
EXTENDED Ave:
80
65
55
NA
40
20
• Pool volume
Ontario Ministry of the
DETENTION
• Pond shape
Environment, 1991, cited in
WET POND Reported Range:
50-100
50-80
55
NA
40
20
• Detention
Schueler et al, 1992
time
Probable Range:
50-95
50-90
10-90
10-90
10-95
20-95
No. Values Considered:
3
3
1
0
1
1
CONSTRUCTED Ave:
65
25
20
50
65
35
• Storage
Harper, et al, 1986; Brown,
STORMWATER
volume
1985; Wotzka and Obert,
WETLANDS Reported Range:
(-20)-100
(-120)-100
(-15)-40
20-80
30-95
(-30)-80
• Detention
1988; Hickock, et al, 1977;
time
Barten, 1987; Melorin, 1986;
Probable Range (6):
50-90
(-5)-80
0-40
—
30-95
—
• Pool Shape
Morris, et al, 1981;
• Wetland's
Sherberger and Davis, 1982;
No. Values Considered:
23
24
8
2
10
8
biota
ABAG, 1979; Oberts, et al,
* Seasonal
1989; Rushton and Dye,
Variation
1990; Hey and Barrett, 1991,
Martin and Smoot, 1986;
Reinelt et al, 1990, cited in
Woodward-Clyde, 1991
Q *
N s.
SO O-
- Q
SO
so cx
U) 5 mm.
(4) Design Criteria: Low slope and adequate length
(5) Design Criteria: Min. E.D. time 12 hours
(6) Design Criteria: Minimum area of wetland equal 1 % of drainage area
(7) No information was available on the effectiveness of removing grease or oil
NA: Not Available
storage volume = 40% excavated trench volume.
-------
TABLE 3-3 COST OF MANAGEMENT PRACTICES FOR CONTROL OF RUNOFF FROM NEWLY DEVELOPED AREAS
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PRACTICE
LAND
REQUIRE-
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CONSTRUCTION
COST
USEFUL
LIFE
ANNUAL
O&M
TOTAL ANNUAL COST
REFERENCES
INFILTRATION
BASIN
High
Ave: SO.5/ cu. ft. storage
Probable Cost: $0.4 - $0.7/cu. ft.
Reported Range: $0.2 - $1.2/ cu. ft.
25<»
Ave: 1% of capital cost
Reported Range: 3% - 13% of capital cost
$0.03-$0.05/cu. ft.
Wiegand, et al,
1986; SWRPC,
1991
INFILTRATION
TRENCH
Low
Ave: $4.0/ cu. ft. storage
Probable Cost: $2.5 - $7.5/cu. ft.
Reported Range: $0.9 - $9.2/ cu. ft.
10(l)
Ave: 9% of capital cost
Reported Range: 5 % - 15% of capital cost
$0.3 - $0.9/cu. ft.
Wiegand, et al,
1986; Macal, et al,
1987; SWRPC,
1991; Kuo, et al,
1988
VEGETATIVE
FILTER STRIP
Varies
Established from existing vegetation-
Ave: $0
Reported Range: $0
Established from seed-
Ave: $400/ acre
Reported Range: $200 - $1,000/ acre
Established from Seed & Mulch-
Ave: $1,500/acre
Reported Range: $800 - $3,500/ acre
Established from sod-
Ave: $11,300/ acre
Reported Range: $4,500 - $48,000/ acre
50*
Natural Succession Allowed to Occur-
Ave: $100/ acre
Reported Range: $50 - $200/ acre
Natural Succession Not Allowed to Occur-
Ave: $800/ acre
Reported Range: $700 - $900/ acre
Natural Succession
Allowed To Occur-
Established from-
Natural Vegetation: $100/
acre
Seed: $125/ acre
Seed & Mulch: $200/ acre
Sod: $700/ acre
Natural Succession Not
Allowed To Occur-
Established from:
Natural Vegetation: $800/
acre
Seed: $825/ acre
Seed & Mulch: $900/ acre
Sod: $1,400/ acre
Schueler, 1987;
SWRPC, 1991
GRASSED SWALES
Low
Established from seed:
Ave: $6.5/ lin. ft.
Reported Range: $4.5 - $8.5/ lin ft.
Established from sod:
Ave: $20/ lin. ft.
Reported Range: $8 - $50/ lin. ft.
50*
Established From Seed or Sod-
Ave: $0.75/ lin. ft.
Reported Range: $0.5 - $1.0/ lin. ft.
Established From Seed:
$1/ lin. ft.
Established From Sod:
$2/ lin. ft.
Schueler, 1987;
SWRPC, 1991
POROUS
PAVEMENT
None
Ave: $1.5/ sq. ft.**
Reported Range: $1 - $2/ sq. ft.**
10<3)
Ave: $0.01/ sq. ft.**
Reported Range: $0.01/ sq. ft.**
0.15/sq. ft.**
SWRPC, 1991;
Schueler, 1987
CONCRETE GRID
PAVEMENT
None
Ave: $1/ sq. ft.**
Reported Range: $1 - $2/ sq. ft.**
20
Ave: (-$0.04)/sq. ft.**
Reported Range: (-$0.04)/ sq. ft.**
0.05/ sq. ft.**
Smith, 1981
-------
00
TABLE 3-3 COST OF MANAGEMENT PRACTICES FOR CONTROL OF RUNOFF FROM NEWLY DEVELOPED AREAS (continued)
&
B
E.
o
CA
o
O
D
•o
to
PRACTICE
LAND
REQUIRE-
MENT
CONSTRUCTION
COST
USEFUL
LIFE
ANNUAL
O&M
TOTAL ANNUAL COST
REFERENCES
SAND FILTER/
FILTRATION BASIN
High
Ave: $5/ cu. ft.
Probable Cost: $2 - $9/cu. ft.
Reported Range: $1 - $ll/cu. ft.
25°)
Ave: Not Available
Probable Cost: 7% of construction cost
Reported Range: Not Available
$0.1 - $0.8/cu. ft.
Tull, 1990
WATER QUALITY
INLET
None
Ave: $2,000/ each
Reported Range: $1,100- $3,000/ each
50
Ave: $30/each(4)
Reported Range: $20-40/each(4)
$150/ each
SWRPC, 1991
WATER QUALITY
INLET WITH SAND
FILTERS
None
Ave: $10,000/ drainage acre
Reported Range: $10,000/ drainage acre
50
Ave: Not Available
Probable Cost: $100/ drainage acre
Reported Range: Not Available
$700/ drainage acre
Shaver, 1991
OIL/ORIT
SEPARATOR
None
Ave: $18,000/ drainage acre
Reported Range: $15,000 - $20,000/
drainage acre
50
Ave: $20/ drainage acre(4)
Reported Range: $5 - $40/ drainage acre141
$1,000/ drainage acre
Schueler, 1987
EXTENDED
DETENTION DRY
POND
High
Ave: $0.5/ cu. ft. storage
Probable Cost: $0.09 - $5/cu. ft.
Reported Range: $0.05 - $3.2/ cu. ft.
50
Ave: 4% of capital cost
Reported Range: 3 % - 5 % of capital cost
$0,007 - $0.3/cu. ft.
APWA Res.
Foundation
WET POND AND
EXTENDED
DETENTION WET
POND
High
Storage Volume < l,000,000cu. ft.:
Ave: $0.5/ cu. ft. storage
Probable Cost: $0.5 - $l/cu. ft.
Reported Range: $0.05 - $1.0/ cu. ft.
Storage Volume > l,000,000cu. ft.:
Ave: $0.25/ cu. ft. storage
Probable Cost: $0.1 - $0.5/cu. ft.
Reported Range: $0.05 - $0.5/ cu. ft
50
Ave: 3% of capital cost
Probable Cost:
<100,000cu. ft. = 5 % of capital cost
>100,000& <1,000,000cu. ft = 3%
of capital cost
> 1,000,000 cu. ft. = 1 % of capital cost
Reported Range: 0.1% - 5% of capital
cost
$0,008- $0.07/cu. ft.
APWA Res.
Foundation;
Wiegand, et al,
1986; Schueler,
1987; SWRPC,
1991
CONSTRUCTED
STORMWATER
WETLANDS
High
Ave: Not available
Reported Range: Not available
50"
Ave: Not Available
Reported Range: Not Available
Not available
iiF ^
1 8
p a-
*~
(i)
>3 g
N) 1
\0 Cu
(2)
"
-------
4.0
MANAGEMENT PRACTICES SUMMARY
Sections 2 and 3 described the most commonly used structural management practices for control
of post-development urban runoff. These management practices remove suspended solids and
pollutants entrained in runoff that result from activities occurring after development. In
addition, many of these practices can reduce post-development volume and peak runoff rates to
equivalent or less than pre-development rates. When these management practices are applied
throughout a watershed, they decrease pollutant loads and help prevent severe erosion and
flooding, which is generally associated with urban development.
4.1 REMOVAL EFFICIENCIES
The effectiveness of the various water runoff treatment management practices were presented
in Table 3-2. As can be seen in the table, the reported pollutant removal rates vary greatly
based on design, construction maintenance, and site-specific conditions. However, many of the
practices, if properly designed, constructed, and maintained, are capably of achieving over 80
percent removal of total suspended solids (TSS).
Pond systems have been widely used for stormwater runoff treatment and can provide moderate
to high pollutant removal if properly designed, constructed, and maintained. Pond systems
include extended detention dry ponds, wet ponds, extended detention wet ponds, wetlands, and
filtration basins. The effectiveness of the pond is dependant on the pond volume, pond shape,
and detention time. Ponds often have a long useful life and relatively low maintenance
requirements. Enhancements to ponds such as fringe marshes and pond systems can improve
the effectiveness of ponds.
In areas where groundwater recharge is desired, and if soils have a high infiltration rate,
infiltration devices can be used. Infiltration devices include infiltration basins, infiltration
trenches and dry wells, porous pavement, and concrete grid pavers. Properly designed,
constructed, and maintained infiltration devices can achieve moderate to high pollutant removal
rates. Storage volume is a critical design factor influencing the effectiveness of infiltration
basins and trenches. However, infiltration devices are often not maintained and consequently
they have a high failure rate within several years of construction.
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Runoff from highly impervious, small drainage areas can be treated with water quality inlets,
water quality inlets with sand filters, and oil/grit separators. However, the effectiveness of these
devices is often low and they are usually not properly maintained.
In low density areas, vegetative filter strips and grassed swales can be used to provide water
quality treatment. In order for these devices to be effective, there should be low flow depths
and long travel times. When runoff is not concentrated, there are appropriate flow depths and
travel times, and they are properly maintained, vegetative filter strips can provide moderate to
high removal rates. Grassed swales often provide low to moderate removal rates and typically
do not provide adequate treatment by themselves. Grassed swales are usually an element of a
management system.
4.2 SERIES OF MANAGEMENT PRACTICES
Series of management practices should be used to achieve high pollutant removal rates. The use
of different types of management practices in series provides more pollutant removal than the
use of single controls. This is the result of some practices being more effective in removing
different types of pollutants than others.
In addition, some management practices will not function properly if the runoff is not treated
prior to the practices. An example of this is infiltration devices will quickly clog as coarse
sediment enters the infiltration media. Therefore, it is especially important to use practices
which trap coarse sediment prior to entering infiltration devices (such as infiltration basins,
infiltration trenches, porous pavement) or filtration basins. Possible practices in series include:
• vegetative filter strip prior to infiltration basin or infiltration trench;
• detention pond prior to filtration basin;
• pond prior to constructed wetland;
• water quality inlet prior to any other practice.
4.3 MAINTENANCE
Proper operation and maintenance of structural treatment facilities is critical to their effectiveness
in mitigating adverse impacts of urban runoff. The proper installation and maintenance of
various BMPs often determines their success or failure (Reinalt, 1992).
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Once ail urban runoff facility is installed, it should receive thorough maintenance in order to
function properly and not pose a health or safety threat. Maintenance should occur at regular
intervals, be performed by one or more individuals trained in proper inspection and maintenance
of urban runoff treatment facilities, and be performed in accordance with the adopted standards
of the State or local government (Ocean County, undated). It is more effective and efficient to
perform preventative maintenance on a regular basis that to undertake major remedial or
corrective action on an as needed basis (Ocean County, undated).
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5.0
RETROFIT
Runoff and pollutant control from existing development is often enhanced through retrofit
projects. Retrofit is the process of replacing or recreating stream or watershed's functions that
have been lost or damaged as the result of urbanization. (MWCOG, 1989) Retrofits are unique
because they are used in areas that have already been urbanized and they are used to reduce
existing nonpoint source pollution. In contrast, the practices discussed in the previous sections
are built as part of a development and are planned and constructed to eliminated expected
nonpoint source pollution.
5.1 DESCRIPTION
This section describes several management practices that are available for retrofit projects. The
advantages and disadvantages of the various retrofit projects are similar to those summarized in
Table 3-1. Because retrofits are a relatively new area, there are little data available on the
effectiveness and cost of retrofits. Retrofit projects include the construction or modification of
facilities for removal of pollutants from stormwater runoff, the stabilization of stream banks and
channels, and the restoration of riparian buffers and wetlands.
5.1.1 Construction or Modification of Pollutant Removal Facilities
Many of the management practices discussed in Sections 2 through 4 of this report cannot be
used in already urbanized areas because they require space that is not typically available in
urbanized areas. However, two types of pollutant removal retrofits can be used. New facilities
can be built in limited land space and existing facilities can be modified to obtain increased water
quality benefits.
5.1.1.1 New Facilities
If there is space available, the management practices discussed in Section 2 through 4 can be
constructed to provide water quality benefits. However, there are often space constraints in
urbanized areas that will not allow construction of these facilities. One option available for these
circumstances is water quality inlets. They can be constructed in highly impervious areas such
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as parking lots. The effectiveness and costs of these facilities would be similar to those
previously discussed.
• Water Quality Inlets - There are several types of water quality inlets - catch
basins, catch basins with sand filters and oil-grit separators. These are discussed
in detail in Sections 2 through 4.
5.1.1.2 Revise Existing Facilities
In the past many stormwater management facilities were constructed to provide peak volume
control. However, most of these facilities provide minimal water quality benefits. These
existing facilities can be modified to provide water quality benefits. Two common modification
can be dry pond conversions and fringe marsh creations.
• Dry Pond Conversion- Many stormwater management dry ponds have been
constructed that provide peak volume control, but provide minimal water quality
benefits. Many of these ponds can be relatively easily modified to provide water
quality control. These modifications can include decreasing the size of the outlet
to increase the detention of the dry pond. This creates an extended detention dry
pond similar to that discussed in Sections 2 through 4. Also, a dry pond's outlet
can also be modified to detain a permanent pool of water and thus create a wet
pond or extended detention wet pond.
• Fringe Marsh Creation- Aquatic vegetation can be planted along the perimeter of
constructed wet ponds or other open water systems to enhance biological pollutant
uptake.
5.1.2 Stabilize Shorelines, Stream Banks and Channels
Urbanization can significantly increase the volume and velocity of stormwater runoff that can
severely erode stream banks and channels. This erosion can create high sediment loads in
coastal receiving water. Stream banks can be stabilized by providing plantings along the stream
bank, or placing boulders, rip-rap, retaining walls or other structural controls in eroding areas.
8040000H:\wp\final\postcon\chap5
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Where feasible, vegetation and other soft practices should be used instead of hard, structural
practices.
5.1.3 Protect And Restore Riparian Forest And Wetland Areas
Riparian forests and wetlands are very effective water quality controls. Consequently, they
should be protected and restored wherever possible. Riparian forest can be restored by
replanting the banks and floodplains of a stream with native species to stabilize erodible soils
and improve surface and groundwater quality.
5.2 EFFECTIVENESS
The effectiveness of retrofit water quality facilities is similar to that discussed in Section 2.2 and
shown in Table 3-2. The effectiveness of revising existing facilities will depend on the
constraints of the existing facility. If sufficient storage volume is available, a dry pond that is
converted into an extended detention dry pond or wet pond could provide removal rates similar
to those discussed in Section 2.2.
Stabilizing stream banks and channels can reduce their erosion and therefore reduce the sediment
loads entering the water body. Protecting and restoring riparian forest and wetland areas
provides a natural area of very effective water quality control.
Table 5-1 summarizes the effectiveness of retrofit projects.
5.3 COST
The use of retrofits is relatively new and therefore there is very limited information on its costs.
The cost of retrofit water quality inlets is higher than the costs reported for developing areas
since existing inlets and pavement would have to be removed to install water quality inlets in
already developed areas. The cost of converting dry ponds into extended detention dry ponds,
wet ponds, and extended detention wet ponds should be substantially less than the cost to
construct these structures in developing areas since it typically only requires minimal
modifications to the existing facility.
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TABLE 5-1 - EFFECTIVENESS OF EXISTING DEVELOPMENT MANAGEMENT PRACTICES
MANAGEMENT
% REMOVAL
MAIN REMOVAL
REFERENCES
PRACTICE
EFFICIENCY
TSS
TP
TN
COD
Pb
Zn
FACTORS
WATER QUALITY Ave:
15
5
5
5
15
5
• Maintenance
Pitt, 1986; Field, 1985;
INLET - CATCH
Schueler, 1987
BASIN (1) Reported Range:
10-95
5-10
5-10
5-10
10-55
5-10
* Sedimentation
storage volume
Probable Range:
10-25
5-10
5-10
5-10
10-25
5-10
No. Values
2
1
1
1
3
1
Considered:
WATER QUALITY Ave:
80
NA
35
55
80
65
* Sedimentation
Shaver, 1991
INLET - CATCH
storage volume
BASINS With Reported Range:
75-85
NA
30-45
45-70
70-90
50-80
SAND FILTER (1)
• Depth of filter
Probable Range:
70-90
-
30-40
40-70
70-90
50-80
media
No. Values
1
0
1
1
1
1
Considered:
WATER QUALITY Ave:
15
5
5
5
15
5
® Sedimentation
Schueler, 1987
INLET - OIL/GRID
storage volume
SEPARATOR (1) Reported Range:
10-25
5-10
5-10
5-10
10-25
5-10
• Outlet
Probable Range:
10-25
5-10
5-10
5-10
10-25
5-10
configurations
Number of
1
1
1
1
1
1
References
DRY POND Ave:
45
25
35
20
45
20
• Storage volume
MWCOG, 1983, City of
MODIFIED INTO
• Detention time
Austin, 1991; Schueler
ED DRY POND Reported Range:
5-90
10-55
20-60
0^0
25-65
(-40)-65
• Pond shape
and Helfrich, 1988; Pope
and Hess, 1988; OWML,
Probable Range
70-90
10-60
20-60
30-40
20-60
40-60
1987; Bait. Dept. P.W.,
(2):
1989, cited in Schueler et al,
6
6
4
5
4
5
1992
No. Values
Considered:
8004000H:\wp\final\postcon\chap5.tbl
5-4
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TABLE 5-1. EFFECTIVENESS OF EXISTING DEVELOPMENT MANAGEMENT PRACTICES (Continued)
MANAGEMENT
% REMOVAL
MAIN REMOVAL
REFERENCES
PRACTICE
EFFICIENCY
TSS
TP
TN
COD
Pb
Zn
FACTORS
DRY POND
Ave:
70
50
35
50
70
60
• Pool volume
Wetzka and Oberta, 1988;
MODIFIED INTO
• Pond shape
Yoosef et al., 1986; Collum,
WET POND
Reported Range:
(-30)-99
10-90
5-85
5-90
10-95
10-95
1985; Driscoll, 1983;
Driscoll, 1986;
Probable Range:
50-99
20-90
10-90
10-90
10-95
20-95
OWML, 1983; Wu et al.,
1988;
No. Values
24
23
11
11
20
17
Holter, 1987; Martin, 1988;
Considered:
Darmay et al., 1989; Horner
et al, 1990; Oberts et al,
1989; Bannerman, 1992;
City of Austin, 1990, cited
in Schueleret al, 1992
DRY POND OR
Ave:
80
65
55
NA
40
20
• Pool volume
Ontario Ministry of the
WET POND
* Pond shape
Environment, 1991, cited in
MODIFIED
Reported Range:
50-100
50-80
55
NA
40
20
• Detention time
Schueler et a], 1992
INTO ED WET
POND
Probable Range:
50-95
50-80
—
—
—
—
No. Values
1
1
1
0
1
1
Considered:
STREAM BANK
Ave:
NA
NA
NA
NA
NA
NA
MWCOG, 1990
STABILIZATION
Reported Range:
NA
NA
NA
NA
NA
NA
Probable Range:
-
-
-
-
-
-
No. Values
0
0
0
0
0
0
Considered:
RIPARIAN
Ave:
70
50
60
70
20
50
• Runoff volume
IEP, 1991; Casman, 1990;
FOREST
• Slope
Glick et al., 1991; VA Dept.
(assumed same as
Reported Range:
20-80
30-95
40-70
60-80
20*
50**
¦ Soil infiltration
of Cons., 1987; Minnesota
Vegetative Filter
rates
PCA, 1989; Schueler, 1987;
Strip)
Probable Range
40-90
30-80
20-60
-
30-80
20-50
• Vegetative cover
Hartigen et al., 1989
(3):
• Buffer length
6
3
2
1
2
2
No. Values
Considered:
8004000H:\wp\final\postcon\chap5.tbl
5-5
Woodward-Clyde
January 28, 1993
-------
TABLE 5-1. EFFECTIVENESS OF EXISTING DEVELOPMENT MANAGEMENT PRACTICES (Continued)
MANAGEMENT
PRACTICE
% REMOVAL
MAIN REMOVAL
EFFICIENCY
FACTORS
REFERENCES
TSS
TP
TN
COD
Pb
Zn
WETLAND Ave:
65
25
20
50
65
35
• Storage volume
Harper et al., 1986; Brown,
(assumed same as
* Detention time
1985; Wotzka and Obert,
Constructed Reported Range:
(-20)-
(-120)-
(-15)-40
20-80
30-95
(-30)-80
• Pool Shape
1988; Hickack et al., 1977;
Stormwater
100
100
• Wetland's biota
Barten, 1987;
Wetlands) Probable Range
0-40
—
30-95
—
• Seasonal
Meloria, 1986; Morris et
(6):
50-90
(-5)-80
Variation
al., 1981; Sheiberger and
6
2
6
4
Davis, 1982; ABAG, 1979;
No. Values
14
14
Oberts et al.,
Considered:
1989; Rushton and Dye,
1990; Hey and Barrett,
1991; Martin and Smoot,
1986; Reinelt et al, 1990,
cited in Woodward-Clyde,
1991
8004000H:\wp\final\postcon\chap5.tbl
5-6
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6.0
REFERENCES
APWA Research Foundation, n.d. "Costs of Stormwater Management Systems." Urban
Stormwater Management. APWA.
Bassler, R.E. n.d. Grassed Waterway Maintenance. Agricultural Engineering Department/
University of Maryland.
British Columbia Research Corporation. 1991. Urban Runoff Quality and Treatment: A
Comprehensive Review. Greater Vancouver Regional District.
Cahill, T.H., W.R. Horner, J. McGuire and C. Smith. October 25, 1991. Interim Report:
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Washington, DC.
Casman, E. 1990. Selected BMP Efficiencies Wrenched from Empirical Studies. Interstate
Commission on Potomac River Basin.
City of Austin Environmental Resource Management Division; Environmental and Conservation
Services Department. 1990. Removal Efficiencies of Stormwater Control Structures.
Environmental Resource Management, Austin, Texas.
City of Austin. 1988. Inventory of Urban Nonpoint Source Pollution Control Practices.
Day, G., D.R. Smith, and J. Bowers. 1981. Runoff and Pollution Abatement Characteristics
of Concrete Grid Pavements. Virginia Water Resources Research Center/ Virginia
Polytechnic Institute.
Dorman, M.E., J. Hartigan R.F. Steg, and T. Quasebarth. August 1989. Retention. Detention
and Overland Flow for Pollutant Removal from Highway Stormwater Runoff. Volume
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Dupuis, T.V. and N.P. Kobriger. July 1985. Effects of Highway Runoff on Receiving Waters.
Volume IV: Procedural Guidelines for Environmental Assessments. FHWA. Report
No. FHWA/RD-84/065.
Field, R. 1985. "Urban Runoff: Pollution Sources, Control,and Treatment." Water Resources
Bulletin. Vol. 21, No. 2. American Water Resource Association.
Finnemore, J.E. October 1982. Stormwater Pollution Control: Best Management Practices.
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Glick, R., M.L. Wolfe, and T.L. Thurow. 1991. Urban Runoff Quality As Affected By Native
Vegetation. Presented at the 1991 International Summer Meeting sponsored by ASAE.
(Albuquerque, New Mexico). ASAE Paper No. 91-2067.
Hartigan, J.P., T.S. George, T.F. Quasebarth and M.E. Dorman. 1989. Retention. Detention,
and Overland Flow for Pollutant Removal from Highway Stormwater Runoff. Vol. II
Design Guidelines. FHWA. Report No. FHWA/RD-89/203.
IEP, Inc. 1991. Vegetated Buffer Strip Designation Method Guidance Manual. Narragansett
Bay Project. USEPA and RI DEM.
Kuo, C.Y., K.A. Cave and G.V. Loganathan. 1988. "Planning of Urban Best Management
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Lindsey G., L. Roberts and W. Page. June 1991. Stormwater Management Infiltration
Practices in Maryland: A Second Survey. MD Department of the Environment,
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Livingston, E. and E. McCarron, J. Cox, and P. Sazone. 1988. The Florida Development
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Lugbill, J. 1990. Potomac River Basin Nutrient Inventory. MWCOG.
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Macal, C.M., and B.J. Broomfield. 1980. Costs and Water Quality Effects of Controlling Point
and Nonpoint Pollution Sources. National Science Foundation, Argonne National
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Metropolitan Washington Council of Governments. 1989. State of the Anacostia - 1989 Status
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Minnesota Pollution Control Agency. 1989. Protecting Water Quality in Urban Areas
Ocean County. Date Unknown. Ocean County Demonstration Study: Stormwater Management
Facilities Maintenance Manual.
Pitt, R. 1986. "Runoff Controls in Wisconsin's Priority Watersheds." Urban Runoff Quality -
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Pitt, R. and G. Shalwly. June 1981. San Francisco NURP Project: NPS Pollution
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Puget Sound Water Quality Authority. June 1989. Managing Nonpoint Pollution - An Action
Plan Handbook for Puget Sound Watersheds.
Schueler, T. December 9, 1992. Performance and Longevity of Urban BMP Systems.
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Management Practices."
Schueler, T., P. Kumble, and M. Heraty. March, 1992. A Current Assessment of Urban Best
Management Practices: Techniques for Reducing Non-Point Source Pollution in the
Coastal Zone.
Schueler, T. 1987. Controlling Urban Runoff: A Practical Manual for Planning and
Designing Urban BMPs. MWCOG.
Shaver, E. 1991. Sand Filter Design for Water Quality Treatment. Presented at 1991 ASCE
Stormwater Conference in Crested Butte, Colorado.
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Silverman , G.S. and M.K. Stenstrom. 1988. "Source Control of Oil and Grease in an Urban
Area." Design of Urban Runoff Quality Controls. Proceedings of an Engineering
Foundation Conference. Potosi, Missouri. July 10-15, 1988. ASCE. pp. 403-420.
Smith, D.R., M.K. Hughes, and D.A. Sholtis. May 30, 1981. Green Parking Lot Dayton.
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Source Water Pollution Control Measures. Technical Report Number 31.
Tull, L. 1990. Cost of Sedimentation/Filtration Basins. City of Austin.
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Division.
Virginia Department of Conservation and Historic Resources, DSWC. 1987. Chesapeake Bay
Research/Demonstration Project Summaries July 1. 1984 - June 30. 1985. VA DCHR.
Washington State Department of Transportation/University of Washington. March 1988.
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Whalen, P. and M.G. Cullum. 1988. An Assessment of Urban Land Use/Storm water Runoff
Quality Relationships and Treatment Efficiencies of Selected Stormwater Management
Systems. South Florida Water Management District Resource Planning Dept.; Water
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Controls." Urban Runoff Quality - Impact and Quality Enhancement Technology.
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Woodward-Clyde. 1989. Analysis of Storm Event Characteristics for Selected Rainfall Gages
Throughout the United States.
Woodward-Clyde. 1986. Methodology for Analysis of Detention Basins for Control of Urban
Runoff Quality. Prepared for Office of Water, NPS Division, USEPA, Wash., D.C.
Young, G.K. and D. Danner. March 1982. Urban Planning Criteria for Non-Point Source
Water Control.
Yousef, Y.A., M.P. Wanielista, H.H. Harper, D.B. Pearce and R.D. Tolbert. July 1985. Best
Management Practices - Removal of Highway Contaminants by Roadside Swales. Final
Report. Florida Department of Transportation.
80040000H:\wp\fina]\postcon\chap6
6-5
Woodward-Clyde
January 28, 1993
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APPENDICES
-------
APPENDIX A
STATE REGULATIONS
-------
STATE STORMWATER MANAGEMENT/BMP REGULATIONS1
State/Region
Regulation/Guidelines*
Where Required
Storm for which post-
develop. peak runoff rate
must be equal or less than
pre-develop.
Required Pollutant
Removal
Volume of Water
Required for Quality
Treatment
Alabama
No state law
—
—
—
—
Alaska
No state law
—
—
—
—
American Samoa
No state law
—
—
—
—
California
No state law
—
—
—
—
Connecticut
No state law
—
—
—
—
Delaware
Sediment and Stormwater
Regulations
Statewide for sites greater than
5,000 sf
both 2 year - 24 hour and
10 year - 24 hour
80% suspended solids
1/2" runoff
Florida
Stormwater Discharge
Regulations of 1982
Statewide for sites requiring
permits
No statewide requirement
80% total annual
pollutant load
No statewide requirement
Guam
No state law
—
—
—
—
Hawaii
No state law
—
—
—
—
Louisiana
No state law
—
—
—
—
Maine
No state law
—
—
—
—
Maryland
Stormwater Management
Regulations of 1984
Statewide for sites greater than
5,000 sf
both 2 year - 24 hour and
10 year - 24 hour
What is achieved by
using the BMPs from
the preferred BMP list
1/2" runoff
"This information is based on telephone contacts completed in 1991.
The state regulations should be consulted for current requirements.
80040000\wp\final\postcon\state.tbl
A-l
Woodward-Clyde
January 28, 1993
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STATE STORMWATER MANAGEMENT/BMP REGULATIONS1
State/Region
Regulation/Guideline*
Where Required
Storm for which post-
develop peak runoff
rate must be equal or
less than pre-develop
Required Pollutant
Removal
Volume of Water Required for
Quality Treatment
Massachusetts
No state law
—
—
—
—
Michigan
No state law
—
—
—
—
Minnesota**
Metropolitan Surface Water
Management Law and
Comprehensive Local Water
Management Act
Mandatory in the 7
metropolitan counties and
voluntary for the remaining
counties.
No statewide
requirement
No statewide
requirement
No statewide requirement
Mississippi
No state law
—
—
—
—
New Hampshire
Water Supply and Waste
Disposal Law
Statewide for sites greater
than 100,000 sf
10 year - 24 hour
New Jersey- Coastal
Zone
Coastal Zone Management
Rules of 1980
For areas requiring coastal
permits
both 2 year - 24 hour
and 10 year - 24 hour
No statewide
requirement
1 year - 24 hour storm or 1 1/4"
rainfall
New York
No state law
—
—
—
—
North Carolina
Administrative Code
In coastal counties 1/4 acre to
1/3 acre
—
—
1" rainfall
Northern Mariana
Island
No state law
—
—
—
—
Ohio**
No state law
—
—
—
—
'This information is based on telephone contacts completed in 1991.
The state regulations should be consulted for current requirements.
80040000\wp\final\postcon\state.tbl
A-2
Woodward-Clyde
January 28, 1993
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STATE STORMWATER MANAGEMENT/BMP REGULATIONS1
State/Region
Regulation/Guideline
Where Required
Storm for which post-
development peak runoff rate
must be equal or less than pre-
develop.
Required Pollutant
Removal
Volume of Water Required
for Quality Treatment
Oregon
No state law
—
—
—
—
Pennsylvania
No state law
—
—
—
—
Puerto Rico
No state law
—
—
—
—
Rhode Island
Design and Installation
Standards for Stormwater
BMPs (will be
incorporated into wetland
laws, expected Dec. 1991)
Wherever coastal or wetland
permit required
both 2 year, 10 year and 100
year
Recommended TSS
removal rate of 80%
Recommended 1" per
impervious acre
South Carolina -
Coastal Zone
South Carolina Coastal
Council Stormwater
Management Guidelines
For some sites within coastal
zone
5 year - 24 hour
No statewide requirement
1" rainfall
Virgin Islands
No state law
—
—
—
—
Virginia -
Stormwater Management
Act of 1989
Mandatory for state sponsored
development, voluntary elsewhere
both 2 year - 24 hour and 10
year - 24 hour
No statewide requirement
1/2" runoff
Virginia -
Chesapeake Bay
Chesapeake Bay Act
For sites greater than 2,500 sf in
Chesapeake Bay Preservation
Areas
both 2 year - 24 hour and 10
year - 24 hour
No net increase in NPS
pollution.
For redevelopment- 10%
reduction in NPS loads
1/2" runoff
Washington
No state law
—
—
—
—
Wisconsin
Water Pollution Law
(permit process being
developed)
Statewide for sites greater than 3
acres
both 2 year and 10 year
What is achieved by
using BMP from the
preferred BMP list
What is required in the
preferred BMP list
~Does not include state water quality standards
** Awaiting Coastal Zone Approval
'This information is based on telephone contacts completed in 1991.
The state regulations should be consulted for current requirements.
80040000\wp\final\postcon\state.tbl
A-3
Woodward-Clyde
January 28, 1993
-------
APPENDIX B
EFFICIENCY DATA
-------
MANAGEMENT PRACTICE'S REMOVAL EFFICIENCY DATA
MANAGEMENT PRACTICE FOR URBAN STORMWATER RUNOFF
Infiltration Basin
Infiltration Trench
Vegetative Filter Strip (VFS)
Grassed Swale
Porous Pavement
Concrete Grid Pavement
Filtration Basins
Water Quality Inlet - Catch Basin
Water Quality Inlet - Catch Basin with Sand Filter
Water Quality Inlet - Oil/Grit Separators
Dry Extended Detention Ponds*
Wet Ponds*
Wet Extended Detention Ponds*
Stormwater Wetlands*
Extended Detention Wetlands*
Natural Wetlands*
Pond/Wetland Systems*
Wetlands
'Compiled by Metropolitan Washington Council of Governments
80040000H:\wp\fina]\postcon\append-b.tb!
B-l
Woodward-Clyde
January 28, 1993
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Mangement Practice: INFILTRATION BASIN
DESCRIP-
TION
LOCA-
TION
WATERSHED
AREA
(acres)
TREATMENT
VOL.
INFIL-
TRATION
RATE
(in./hour)
REMOVAL EFFICIENCY (%)
STUDY TYPE
REFERENCE
TSS
TP
SP
TN
N03
COD
Pb
Zn
OTHER
Infiltration
Basin
DC
5 ac. minimum,
20 ac.
maximum
Complete 2 yr
runoff volume
0.27
minimum
99
65-75
60-70
BAC: 98
BOD: 90
TM: 95-99
From field
testing of
similar rapid
infiltration land
treatment
systems
NVPDC, 1979
and EPA, 1977
cited in
Schueler, 1987
Infiltration
Basin
DC
5 ac. minimum,
50 ac.
maximum
runoff from 1
in. storm
0.27
minimum
90
60-70
55-60
BAC: 90
BOD: 80
TM: 85-90
From modeling
studies and
field studies
NVPDC, 1979
and Griffin, et
al, 1980 cited
in Schueler,
1987
Infiltration
Basin
DC
5 ac. minimum,
SO ac.
maximum
0.5 in. runoff
/impervious
acre
0.27
minimum
75
50-55
45-50
BAC: 75
BOD: 70
TM: 75-80
From modeling
studies and
field studies
NVPDC, 1979
and Griffin, et '
al, 1980 cited
in Schueler,
1987
Recharge
Device
Great
Lakes
Efficiency
independent of
watershed area
109 cf./ac.
6.0
45
45
45
45
45
45
45
45
Read from
chart
developed from
NURPdata
analysis
EPA, 1983
Recharge
Device
DC
Efficiency
independent of
watershed area
Runoff from 1
in. storm
0.5 to 8.27
75-
98
75-98
75-98
75-98
75-98
75-98
75-98
75-98
From model
Woodward-
Clyde, 1986
Recharge
Device
DC
Efficiency
independent of
watershed area
0.5 in.
runoff/imper.
acre
0.5 to 8.27
55-
90
55-90
55-90
55-90
55-90
55-90
55-90
55-90
From model
Woodward-
Clyde, 1986
Recharge
Device
Great
Lakes
Efficiency
independent of
watershed area
109 cf./ac.
6.0
50
50
50
50
50
50
50
50
From model
Woodward-
Clyde, 1986
80040000H:\wp\final\postcon\appcnd-b.tbl
B-2
Woodward-Clyde
January 28, 1993
-------
Management Practice: INFILTRATION TRENCH
DESCRIP-
TION
LOCA-
TION
WATER-
SHED
AREA
(Acres)
TREAT-
MENT
VOL.
INFIL-
TRATION
RATE
(In. /Hour)
REMOVAL EFFICIENCY (%)
STUDY TYPE
REFERENCE
TSS
TP
SP
TN
N03
COD
Pb
Zn
OTHER
Infiltration
trench
DC
5 ac max
Complete
storm
volume
0.27
minimum
99
65-75
60-70
BAC: 98
BOD: 90
TM: 95-99
From field
testing of
similar rapid
infiltration
land treatment
systems
NVPDC, 1979 and
EPA, 1977 cited in
Schueler, 1987
Infiltration
trench
DC
5 ac max
runoff
from 1 in.
storm
0.27
minimum
90
60-70
55-60
BAC: 90
BOD: 80
TM: 85-90
From modeling
studies and field
studies
NVPDC, 1979 and
Griffin, et al, 1980
cited in Schueler,
1987
Infiltration
trench
DC
5 ac max
0.5 in.
runoff/
impervious
acre
0.27 min
75
50-55
45-55
BAC: 75
BOD: 70
TM: 75-80
From modeling
studies and field
studies
NVPDC, 1979 and
Griffin, et al, 1980
cited in Schueler,
1987
Infiltration
trench
NA
NA
NA
NA
96
41
61
BOD: 84
NA
Biggers, et al,
1980 and USEPA,
1983 cited in Kuo,
et al, 1988
Infiltration
trench
NA
NA
NA
NA
50
60
(-8)
NA
NURP, 1983 cited
in Lugbill, 1990
Recharge
Device
Great
Lakes
Efficiency
independent
of
watershed
area
109 cf./ac.
6.0
45
45
45
45
45
45
45
45
Read from chart
developed from
NURP data
analysis
EPA, 1983
Recharge
Device
DC
Efficiency
independent
of
watershed
area
Runoff
from 1 in.
storm
0.5 to 8.27
75-98
75-98
75-98
75-98
75-98
75-98
75-98
75-98
From model
Woodward-Clyde,
1986
80040000H:\wp\final\postcon\append-b.tbl
B-3
Woodward-Clyde
January 28, 1993
-------
Management Practice: INFILTRATION TRENCH
DESCRIP-
TION
LOCA-
TION
WATER-
SHED
AREA
(Acres)
TREAT-
MENT
VOL.
INFIL-
TRATION
RATE
(In./Hour)
REMOVAL EFFICIENCY (%)
STUDY TYPE
REFERENCE
TSS
TP
SP
TN
N03
COD
Pb
Zn
OTHER
Recharge
Device
DC
Efficiency
independent
of
watershed
area
0.5 in.
runoff/imp
er.
acre
0.5 to 8.27
55-90
55-90
55-90
55-90
55-90
55-90
55-90
55-90
From model
Woodward-Clyde,
1986
Recharge
Device
Great
Lakes
Efficiency
independent
of
watershed
area
109 cf./ac.
6.0
50
50
50
50
50
50
50
50
From model
Woodward-Clyde,
1986
80040000H:\wp\final\poslcon\appcnd-b.tbI
B-4
Woodward-Clyde
January 28, 1993
-------
Management Practice: VEGETATIVE FILTER STRIP (VFS)
DESCRIPTION
LOCA-
TION
WATER-
SHED
AREA (ac)
VFS
SLOPE
VFS
LENGTH
POLLUTANT REMOVAL EFFICIENCY (%)
STUDY
TYPE
REFERENCE
TSS
TP
SP
TN
N03
COD
Pb
Zn
OTHER
Vegetative buffer
RI
NA
NA
NA
Sec Chart
Based on
multiple
aimulations
of pollutant
(TSS)
generation,
transport &
removal for
buffer strips
under various
site
conditions
using the P8
urban
catchment
model.
IEP, 1991
Vegetative filter
NA
2.5%
85'
Dropped
from 80% to
50% in 1
season
Varied from
20-80%
Ave= 53%
16 month
study for
sediment
control
Hayes &
Hairston, 1983
cited in
Casman, 1990
Orchard grass
buffer
Virginia
NA
NA
31'
70-98
65-95
(-192J-70
66
Monitored
test plots, no
information
on pollution
source
Dillaha, et al,
1989 cited in
Glick, et al,
1991
Bluegrass sod
buffer
NA
NA
4'
78
Pollutant
source - up
slope bare
soil
Neibling and
Alberts, 1979
cited in Glick,
et al, 1991
80040000H:\wp\final\postcon\appcod-b.tbl
B-5
Woodward-Clyde
January 28, 1993
-------
Management Practice: VEGETATIVE FILTER STRIP (VFS)
DESCRIPTION
LOCA-
TION
WATER-
SHED
AREA (ac)
VFS
SLOPE
VFS
LENGTH
POLLUTANT REMOVAL EFFICIENCY (%)
STUDY
TYPE
REFERENCE
TSS
TP
SP
TN
N03
COD
Pb
Zn
OTHER
Grass level
spreader
Virginia
NA
NA
70'
70
(Increasing
length from
70* to 150*
increased
removal rates
only
minutely)
28
20
51
NN:11
Monitored
March to
June '87 - 8
storms,
Pantops
Shopping
Center,
Charlottesvill
e, VA
VA Dept. of
Cons., 1987
Filter strip-
properly designed
and operated
Minn.
NA
NA
NA
30-50
Nonpoint
Source Control
Task Force,
1983 cited in
Minnesota
PCA, 1989 ,
Turf strip
D.C.
NA
NA
20'
20-40
0-20
0-20
0-20
TM: 20-40
Schueler, 1987
Forested strip
with level
spreader
D.C.
NA
NA
100'
80-100
40-60
40-60
60-80
TM: 80-
100
Schueler, 1987
VFS- Source
parking lot
NA
NA
NA
Buffer not effective in reducing pollutant.
Preliminary study, final conclusions not yet reached, but prelim indicates buffer not effective for urban runoff.
Possible reasons, 1) conc. in urban runoff significantly lower than agricult. or forest 2) urban runoff has excess
transport capacity when entering buffer and detaches sediment and adsorbed pollutants with no deposition
occurring.
Glicic, el al,
1991
Vegetative
Control
NA
NA
NA
See Chart
9096 of
TSS
removal
50 % of
TSS
removal
CU:60%
of TSS
removal
Generated
from
research, see
grass swales
along
highways
table
Hartigan,
et.al., 1989
Agriculture VFS
NA
NA
NA
o Effectiveness
as it is being hi
o VFS more ef
o Effectiveness
of VFS de
ried.
ective in r
of VFS hi
ureases with ti
emoving SS th
;hly dependen
me as sediment
in nutrients
on condition o
accumul
f filter
ites within
it unless the v
egetation can
grow as fast
Casman, 1990
80040000H:\wp\final\poslcon\appcnd-b.tbl
B-6
Woodward-Clyde
January 28, 1993
-------
Management Practice: VEGETATIVE FILTER STRIP (VFS)
DESCRIPTION
LOCA-
WATER-
VFS
VFS
POLLUTANT REMOVAL EFFICIENCY (%)
STUDY
REFERENCE
TION
SHED
AREA (ac)
SLOPE
LENGTH
TSS
TP
SP
TN
N03
COD
Pb
Zn
OTHER
TYPE
Agriculture
vegetated filter.
D.C.
NA
11%
30'
95
80
70
4
NH4: 69
TKN: 80
P04: 30
Runoff from
Agriculture
feed lot,
storm
Dillah et al,
1988 cited in
Casman, 1990
NA
11%
15'
87
63
61
-36
NH4: 34
TKN: 64
P04: -20
simulated- 2
year in
Potomac
Region. Did
not capture
NA
16%
30'
88
57
71
17
NH4: -35
TKN: 72
P04: -51
change in
filter
efficiency
over period
of time. 2
NA
16%
IS1
76
52
67
3
NH4: -21
TKN: 69
P04: -108
test runs
separated by
7 days
Agriculture, VFS
on sandy loam
MD
NA
3%
30'
82
42
Runoff:
41
Leachale:
87
Total: 83
Agriculture
study, 3
simulated
storms over 3
weeks during
Magette, 1987
cited in
Casman, 1990
NA
4%
30*
82
25
Runoff:
48
growing
season.
Subsurface
NA
5%
so-
86
52
Runoff:
51
Leachate:
3
Total: 11
leaching loss
important
component of
inorganic N
movement
from
NA
3%
ls-
65
22
Runoff:
-15
Leachate:-
10
Total:-20
agricultural
areas
NA
4%
15'
66
27
Runoff:-6
80040000H:\wp\final\postcon\appcnd-b.tb!
B-7
Woodward-Clyde
January 28, 1993
-------
Management Practice: VEGETATIVE FILTER STRIP (VFS)
DESCRIPTION
LOCA-
WATER-
VFS
VFS
POLLUTANT REMOVAL EFFICIENCY (%)
STUDY
REFERENCE
TION
SHED
AREA (ac)
SLOPE
LENGTH
TSS
TP
SP
TN
N03
COD
Pb
Zn
OTHER
TYPE
NA
5%
15'
72
41
Runoff:
-17
Leachate:
39
Total:36
Agriculture,
mixture rye,
fescues and
bluegrass on loam
soil:
Surface Runoff
Only:
Surface and
Groundwater:
NA
2%
2%
85'
85'
99
95
94
84
OP:98
TKN: 99
NH4: 88
OP:92
TKN: 92
NH4:78
Measured
surface and
subsurface
leaving site
over 2 years.
Parlor waste
discharged 2
times a day.
Schwer &
Clausen, 1989
cited in
Casman, 1990
Snow-melt
35
TKN: 57
Seasonal
Efficiency
Winter
95
TKN: 94
Growing
96
TKN: 98
Spring/Fall
96
TKN: 94
o As loading rates increase, efficiency decreases
80040000H:\wp\final\postcon\flppcnd-b.lbl
B-8
Woodward-Clyde
iftnuaiy 28, 1993
-------
Management Practice: GRASSED SWALE
DESCRIPTION
LOCATION
SLOPE
LENGTH
(FT)
REMOVAL EFFICIENCY (%)
STUDY TYPE
REFERENCE
TSS
TP
SP
TN
N03
COD
Pb
Zn
OTHER
Low vegetation density &
height
DC
2-6%
NA
No significant water quality benefit measured, but report concluded that if residence time and
infiltration capability increased, then could be effective BMP
Study 3 swales, NURP
at Wash. DC suburbs
Schueler, 1987;
British Columbia
Res. Corp., 1991;
and EPA, 1983
Grassed swale with no check
dams
DC
high
NA
0-20
0-20
0-20
TM: 0-20
OD: 0-20
Schueler, 1987
Grassed swale with check
dams
DC
low
NA
20-40
20-40
20-40
TM: 0-20
OD: 20-40
Schueler, 1987
Swale in low density
residential
FL
NA
NA
99 +
99 +
99 +
TKN: 99 +
BOD: 99
Monitoring study in
Brevard Co, Florida
Post, et al 1982 cited
in Whalen, et al,
1988
Swale for commercial
parking lot designed to
provide surface detention,
with a clay layer placed
below top soil layer to
prevent infiltration
NH
low
NA
Negli-
gible
Negli-
gible
25
50-65
50
TKN: 28
BOD: 11
Cu: 48
Cd: 42
NH3: 25-51
ON: Not sig.
NN: 32
Monitoring study in
Durham, NH; Over 11
storms monitored in
Durham, NH as part
of NURP.
Oakland, 1983, and
Athayde, et al 1983
cited in Whalen, et
al, 1988; Schueler,
1987; EPA, 1983;
British Columbia
Res. Corp, 1991
Swales
NA
NA
NA
Pollutants may reach ground water and discharge indirectly into receiving water
Whalen, et al, 1988
80040000H:\wp\final\postcon\append-b.tbl
B-9
Woodward-Clyde
January 28, 1993
-------
Management Practice: GRASSED SWALE
DESCRIPTI
ON
LOCA
SLOPE
LENGTH
REMOVAL EFFICIENCY (%)
TION
(FT)
TSS
TP
SP
TN
N03
COD
Pb
Zn
OTHER
STUDY
TYPE
REFERENCE
Swale
NA
NA
NA
80
80
60
Cu: 60
Compiled
from
literature
Horner, 1988
cited in British
Columbia Res.
Corp, 1991
Vegetative
Control
*
*
~
See
Chart
90% of TSS removal
50% of
TSS
removal
Cu: 60% of TSS removal
~Generated
from
research, see
grass swales
along
highways
table
Hartigan, et a],
1989
Roadside
drainage
system -
grass swales.
Toront
o
residen
tial
NA
NA
Warm Cold
Weather Weather
Weighted
Storm Melt Total
Water Water Annual
90 13 28
Warm Cold
Weather Weather Weighted
Storm Melt Total
Water Water Annual
Flow: 90 13 20
Monitoring
conducted
1984-1985.
100 rains.
50 snowmelts
monitored.
Pitt and (
Mclean, 1986
cited in Pitt,
1986
Agricultural
vegetated, 1
foot channel,
4% cross
slope
DC
5%
30'length
58
19
7
-158
NH4:-11
TKN:9
P04:31
Runoff from
Agr. feedlot,
storm
simulated 2
yr in
POtomac
Region. Did
Dillaha et al,
1988
cited in
Casman, 1990
15' length
31
2
0
-82
NH4:1
TKN:1
P04:-3
not capture
change in
filter
efficiency o
er time. 2
test runs
separated by
7 days.
80040000H:\wp\final\postcon\appcnd-b.tbl
B-10
Woodward-Clyde
January 28, 1993
-------
Management Practice: GRASSED SWALES ALONG HIGHWAYS
WATER
-SHED
LENGTH
REMOVAL EFFICIENCY (%)
STUDY
TYPE
DESCRIP-
TION
LOCATION
AREA
(Acres)
SLOPE
(FT)
TSS
TP
TKN
Pb
Zn
Cr
Ni
Cu
OTHER
REFERENCE
Grass swale
along 1-4 @
Mflitland
Florida
NA
0.8%
160
91%
90%
44%
88%
41%
17 storm
events, 8
month
period.
Removal
efficiencies
vary by
storm
Yousef, et al,
1985
Grass swale
along 1-5 @
NE 158th
ADT =
.100,000 veh
Washington
NA
220
80%
83%
69%
63%
Homer, 1982
cited in
Dupuis, 1985
Grass swale
along:
1-4 @ South
Orange
Blossom Trail
Florida
0.56 ac/
6356
imperv.
<3.5%
200
87-98%
-47 to
+26%
13-51%
33-94%
69-81%
29-65%
42-78%
NOx: 12-
52%
TOC:
58-66%
13 storms
monitored
Hartigan, et
al 1989
1-66
1-270
Virginia
Maryland
1.27 ac/
67%
imperv.
NA
4.7%
3.2%
200
200
52-65%
36-41%
-33 to
+ 12%
17-26%
3-46%
17-78%
8-98%
27-49%
18-47%
-34 to
+ 16%
5 - 83%
12-28%
-43 to
+22%
NOx: 2-
11%
TOC:
29-76%
Nox: -28
to -143%
12 storms
monitored
4 storms
monitored
Removal of metals correlated with TSS removal. Nutrient removal varies widely, appears unrelated to TSS removal. Results suggest that not only
channel lengths, but also channel slope and channel geometry (to reduce flow depth) also contribute to TSS removal, and metals removal
Grass lined
channel, flow
depth less
than 6 inches
Washington
NA
< 8%
200
80%
80%
COD:
80%
Washington
State, 1988
80040000H:\wp\fmal\postcon\appcnd-b.tbI
B-l 1
Woodward-Clyde
January 28, 1993
-------
Management Practice: POROUS PAVEMENT
DESCRIPTION
LOCATION
WATER-
SHED
AREA
(Acres)
TREAT-
MENT
VOL.
(In/Acre)
INFIL-
TRATION
RATE
(In/Hour)
REMOVAL EFFICIENCY (%)
STUDY TYPE
REFERENC
E
TSS
TP
SP
TN
N03
COD
Pb
Zn
OTHER
Porous pavement -
partial exfiltration
Rockville, MD
NA
NA
NA
95
65
85
82
98
99
Pollutant export
over series of
storms monitored
at a terminal
underdrain and
compared to
runoff From
adjacent
conventional
pavement
OWML,
1983, 1986
cited in
Schueler,
1987
Porous Pavement -
partial exfiltration
Prince William,
VA
NA
NA
NA
82
65
80
Pollutant export
over series of
storms monitored
at a terminal
underdrain and
compared to
runoff from
adjacent
conventional
pavement
OWML,
1983, 1986
cited in
Schueler,
1987
80040000H:\wp\fmal\postcoii\flppcnd-b.tbI
B-12
Woodward-Clyde
January 28, 1993
-------
Management Practice: CONCRETE GRID PAVEMENT
DESCRIPTION
LOCATION
REMOVAL EFFICIENCY (%)
STUDY TYPE
REFERENCE
REDUCTION IN STORM RUNOFF
3 types of grid pavements:
lattice, castellated and
poured-in place pavers, all
at 4% slope
Lab
98.7 TO 100
Lab setting. Runoff volume and pollution
reduction associated for 10 simulated
rainfall events and most with return period
of less than 10 years
Day, 1981
Lattice papers (turfstone)
Downtown municipal
parking lot Dayton,
Ohio
65 to 97
Monitoring study for a period of 10 weeks
for 11 rain fall events with return period of
less than 2 years. The results were
compared to computer simulation of the
hydrological characteristic of the lot as if it
were paved in asphalt.
Smith, et al., 1981
80040000H:\wp\final\po3lccFn\appcnd-b .lb!
B-13
Woodward-Clyde
January 28, 1993
-------
Management Practice: FILTRATION BASINS
DESCRIPTION
LOCATION
WATER-
SHED
AREA
(ACRES
TREAT-
MENT
VOL.
(In.Acre)
FILTRA-
TION
RATE
(In/Hour)
REMOVAL EFFICIENCY («)
STUDY
TYPE
REFERENCE
TSS
TP
SP
TN
N03
COD
Pb
Zn
OTHER
Filter media
consisting of
varying layers of
gravel, sand
Lab
NA
NA
NA
80-95
30
BOD:70-90
OP: 50
Lab study
Wanielista, et
al 1981 cited
in City of
Austin, 1988
Filter media
consisting of alum
sludge/sand mixture
Lab
NA
NA
NA
80-90
90
BOD:70-90
OP: 90
Lab study
Wanielista, et
al 1981 cited
in City of
Austin, 1988
Test filter
Lab
NA
NA
NA
OP:75-92
Field study
Harper et al,
1982 cited in
City of Austin,
1988
In-line filtration
basin, overflows
when storage vol.
exceeded
Barton Creek
Square Mall,
Austin, TX
NA
NA
NA
78.3
27.3
33.3
59.5
BOD:75.6
TOC:60.0
TDS:(-12.9)
NN:(-111.0)
Fe:55.0
FCol:80.7
Excludes
storms
which
overtop the
pond
Welborn et al,
1987 cited in
City of Austin,
1988
In-line filtration
basin, overflows
when storage vol.
exceeded
Barton Creek
Square Mall,
Austin TX
NA
NA
NA
58.1
49.9
32.4
38.7
47.4
BOD:75.6
TOC:50.0
TDS:8.9
NN:(-47.3)
TKN:49.4
Fe:49.2
FCol:82.9
Includes
storms
which
overtop
pond
City of Austin,
1988
Filtration basin -
filter media 3" sod,
4" course sand, 8?
gravel
Highwood
Apartments
Austin, TX
3 ac J50%
imperv.
1/2"
runoff
86
31
45
71
49
TP04:19
NN:(-5)
TKN:48
27 storms
monitored
between
1985-1987
City of Austin,
1990
Filtration basin -
filter media 18"
fine sand, 12"
coarse sand, 6"
gravel
Barton Creek
Square Mall,
Austin, TX
79 ac./7%
imperv.
1/2"
runoff
75
44
50
88
82
TP04:59
NO2+N03:
(-13)
TKN:64
30 storms
monitored
between
1985-1987
City of Austin, ¦
1990
80040000H:\wp\finAl\postcon\appcnd-b.tbl
B-14
Woodward-Clyde
January 28, 1993
-------
Management Practice: FILTRATION BASINS
DESCRIPTION
LOCATION
WATER-
SHED
AREA
(ACRES
TREAT-
MENT
VOL.
(In.Acre)
FILTRA-
TION
RATE
(In/Hour)
REMOVAL EFFICIENCY (%)
STUDY
TYPE
REFERENCE
TSS
TP
SP
TN
N03
COD
Pb
Zn
OTHER
Filtration basin -
filter media 12"
sand, filter fabric,
gravel
Jollyville,
Austin, TX
9.5
ac/81%
imperv.
1/2"
runoff
87
32
68
81
80
TP04:61
N02+N03:(-
79)
TKN:62
20 storms
monitored
between
1988-1989
City of Austin,
1990
Off-line
sedimentation/
filtration basin
Austin, TX
NA
equal or
less than
1/2"
runoff
80-
100
60-
80
20-
40
OD:40-60
M:60-80
BAC:40-60
Estimates
based on
above
noted
studies
City of Austin,
1990
On-line sand/sod
filtration basin
Austin, TX
NA
equal or
less than
1/2"
runoff
80-
100
0-20
20-
40
OD:20-40
M:40-60
BAC:20-40
Estimates
based on
above
noted
studies
City of Austin,
1990
On-line sand
filtration basin
Austin, TX
NA
equal or
less than
1/2"
runoff
60-80
40-
60
o o
-------
Management Practice: WATER QUALITY INLET - CATCH BASIN
DESCRI-
PTION
LOCA-
TION
WATER
-SHED
AREA
(Acres)
TREAT-
MENT
VOL.
(In/Acre)
REMOVAL EFFICIENCY (%)
STUDY
TYPE
REFERENCE
TSS
TP
SP
TN
NO
3
COD
Pb
Zn
OTHER
Catch
basin
cleaned 2
times a
year
Toronto
Residen
tial
NA
Warm Cold Weighted
Storm Melt Total
Water Water Annual
8 8 8
Monitoring
conducted
during
1984 &
1985. 100
rains, 50
snowmelts
monitored
Pitt &
McLean, 1986
cited in Pitt,
1986
Catch
basins -
cleaned 2
times a
year
Boston,
Mass.
NA
NA
60-
97
10-
56
BOC:
54-88
NA
Aronson,
1983 and
Field, 1982
cited in Field,
1985
80040000H: \wp\final\postcon\append-b. tbl
B-16
Woodward-Clyde
Januaiy 28, 1993
-------
Management Practice: WATER QUALITY INLET - CATCH BASIN WITH SAND FILTER
DESCRIPTION
LOCATION
DRAINAGE
AREA
LOCATION
REMOVAL EFFICIENCY (%)
STUDY TYPE
REFERENCE
TSS
TP
SP
TN
N03
COD
Pb
Zn
OTHER
Catch Basin with
sand filter
Austin, Texas
5 ac max
75-86
31-44
45-68
71-88
49-80
Monitoring studies
by City of Austin,
Texas for 3
filtration sites:
Highwood, BCSM
and Jollyville 1.
Removal rates for
pollutants have
not been widely
tested, but they
are expected to
have removal
efficiencies similar
to those of
filtration basins
for highly
impervious
drainage areas that
are less than 5
acres. Results of
monitoring studies
for filtration
basins in Austin,
Texas is med.
Shaver, 1991
80040000H:\wp\fmal\postcon\append-b.tbl
B-17
Woodward-Clyde
January 28, 1993
-------
Management Practice: WATER QUALITY INLET/OIL-GRIT SEPARATORS
DESCRIPTION
LOCATION
WATER-
SHED
AREA
(Acres)
TREAT-
MENT
VOL.
(In/ Acre)
REMOVAL EFFICIENCY {%)
STUDY
TYPE
REFERENC
E
TSS
TP
SP
TN
N03
COD
Pb
Zn
OTHER
Wfater quality
inlet - 3 chamber
NA
1 ac
impervio
us area
max
400 cu ft
wet storage
per
impervious
acre
0-20
Insuff.
knowledge
Insuff.
knowledge
Insuff.
knowledge
insuff.
knowledge
Insuff.
knowledge
BAC insuf.
knowledge
Pollutant
removal
capability
of water
quality
inlets has
never been
tested in
the field,
but some
general
estimates
inferred
from
studies on
similar
structures
such as
catch
basins and
oil/water
separators.
Schueler,
1987
Catch basin 3
chamber-
cleaned twice a
y-
NA
1 ac max
NA
10-25
5-10
5-10
5-10
10-25
5-10
Nutrients 5-10
Large particles
- 50% eff.
Finer particles
assoc. w/large
portion of
heavy metals
and organic
pollutants
resuspended.
Pitt, 1985
cited in
Schueler,
1987 and
City of
Austin, 1988
80040000H:\wp\fina]\postcon\append-b.tbl
B-18
Woodward-Clyde
Januaiy 28, 1993
-------
Management Practice: STREET CLEANING - POLLUTANT REMOVAL IN RUNOFF WATER
DESCRIPTION
LOCATION
WATER-
SHED
AREA
(Acres)
REMOVAL EFFICIENCY (%) IN RUNOFF
STUDY TYPE
REFERENCE
TSS
TP
SP
TN
N03
COD
Pb
Zn
OTHER
Street cleaning on
smooth streets.
One or more
passes/week
One pass/2 weeks
One pass/month
One pass/2 months
One pass/3 months
Toronto
residential
NA
Warm Cold
Weather Weather Weighted
Storm Melt Total
Water Water Annual
25 0 5
23 0 5
20 0 4
16 0 3
13 0 3
Outfall & source
area monitoring
conducted during
1984 & 1985. 100
rains, 50 snowmelts
monitored
Pitt & McLean,
1986
Street cleaning on
rough streets
One or more
passes/week
One pass/2 weeks
One pass/month
One pass/2 months
One pass/3 months
Toronto
residential
NA
Warm Cold
Weather Weather Weighted
Storm Melt Total
Water Water Annual
15 0 3
12 0 2
10 0 2
7 0 1
6 0 1
Outfall & source
area monitoring
conducted during
1984 & 1985. 100
rains, 50 snowmelts
monitored
Pitt & McLean,
1986 cited in
PiH, 1986
Broom street
sweeping
National
NA
No significant reduction in urban runoff quality except in areas with accelerated pollutant accumulations
(commercial and industrial zones) and in areas with direct surface water runoff to the receiving body.
NURP studies
monitored 381 storm
events under control
conditions and 277
during street
sweeping operations
EPA, 1982 cited
in City of Austin,
1988
Rotary broom
sweeper
Bellevue,
Washington
NA
No decrease and possible increase in loadings of solids in runoff from city streets
NURP study
Cited in Puget
Sound Water
Quality
Authority, 1989
Street sweeping
National
NA
Ineffective in 4 out of 5 areas studied
NURP study
Cited in Puget
Sound Water
Quality
Authority, 1989
Street cleaning, 3
passes/week
Castro Valley,
Alameda
County, CA
NA
Less
than 10
35
TS:20
Cu: Less
than 10
In-situ, NURP
funded
Cited in Pitt, et
al, 1981
80040000H:\wp\fmal\postcon\appcad-b.tbl
B-19
Woodward-Clyde
January 28, 1993
-------
Management Practice: STREET CLEANING - POLLUTANT REMOVAL IN RUNOFF WATER
DESCRIPTION
LOCATION
WATER-
SHED
AREA
(Acres)
REMOVAL EFFICIENCY (%) IN RUNOFF
STUDY TYPE
REFERENCE
TSS TP SP TN N03 COD Pb Zn OTHER
Street sweeping
National
NA
o Based on statistical testing, no significant reductions in EMCS are realized by street sweeping.,
o Benefits of street sweeping, if any, are not large (i.e. greater than 50%), and an even larger site
data ba9e is required to identify the possible effect,
o Street sweeping increasing EMCS generally not shown by the data, though it could occur in
isolated, site specific cases.
5 NURP projects, 10
sites, compared end-
of-pipe
concentrations for
adjacent swept and
unswept basins
Cited in EPA,
1983
80040000H:\wp\final\postcon\append-b.tbl
B-20
Woodward-Clyde
January 28, 1993
-------
Management Practice:
STREET CLEANING - POLLUTANT REMOVAL ON STREET SURFACE
DESCRIPTION
LOCATION
WATER-
SHED
% REMOVAL ON STREET SURFACE
STUDY
TYPE
REFERENCE
AREA
(Acres)
TSS
TP
SP
TN
N03
COD
Pb
Zn
OTHER
Intensive street
cleaning programs
NA
NA
TS: 25-50
NA
Pitt, 1985 cited in
City of Austin,
1988
Broom sweeper
Virginia
NA
40
42
31
35
47
BOD: 43
TS: 55
NA
NVPDC, 1979 cited
in City of Austin,
1988
Vacuum sweeper
Virginia
NA
74
77
63
76
85
BOD: 77
TS: 93
NA
NVPDC, 1979 cited
in City of Austin,
1988
Street sweeping
Wise.
NA
TS: 10
NURP study
in Wise.
SEWRPC, 1983
cited in City of
Austin, 1988
Street cleaning -
mechanical and
vacuum-assisted
mechanical,
frequency varied
between 2 passes per
day and less than 1
pass per week:
Asphalt in good
condition
Asphalt in poor
condition
San Jose, CA
NA
30-60
40
5-12
30-60
40
5-12
30-60
40
5-12
TS: 30-60
TKN: 30-60
OP: 30-60
TS: 40
TKN: 40
OP: 40
TS: 5-12
TKN: 5-12
OP: 5-12
In-situ
Removal
efficiencies
for COD,
TKN, Pb,
OP, Zn, Cr,
Cu, Cd
approx equal
toTS
Pitt, 1979 cited in
Finnemore, 1982
Rough oil and
screenings surface
80040000H: \wp\final\postcon\append-b .tbl
B-21
Woodward-CIydc
January 28, 1993
-------
Management Practice:
STREET CLEANING - POLLUTANT REMOVAL ON STREET SURFACE
DESCRIPTION
LOCATION
WATER-
SHED
AREA
(Acres)
% REMOVAL ON STREET SURFACE
STUDY
TYPE
REFERENCE
TSS
TP
SP
TN
N03
COD
Pb
Zn
OTHER
Mechanical sweeping
RA Vacuum
Castro Valley,
Alameda
County, CA
Castro Valley,
Alameda
County, CA
NA
47-65%
59-71 %
54-63%
58-74%
52-66%
60-71%
TS: 53-64
TKN: 50-63
OP: 52-64
Cu: 55-64
TS: 61-69
TKN: 60-72
OP: 58-70
Cu: 57-70
RA is most
effective in
cleaning
streets with
light
loadings; as
loadings
become
heavier, the
difference
between the
two becomes
insignificant.
Cited in Pitt, et al,
1981
Street sweeping, 4
passes per month
(1/week)
Wisconsin:
Residential
NA
2%
8-12%
TS: 4
Simulation
model studies
Cited in
Southeastern
Wisconsin Regional
Planning, 1991
Commercial
NA
3656
53%
TS: 47
Industrial
NA
27%
37%
TS: 28
Street cleaning,
Cleaning
One
Two
Three
NA
Adimi, 1976 cited
mechanical sweeper
Frequency Pass
Passes Passes
in Young, et al,
efficiency as a
(Days)
i%l
(%) (%)
1982
function of sweeping
frequency and
60
41.0
74.0
94.8
number of passes
30
60.5
87.9
97.6
14
66.0
92.1
98.4
7
75.5
95.0
99.0
1
79.4
96.4
99.3
80040000H:\wp\finaI\po5lconVappcnd-b.tbl
B-22
Woodward-Clyde
January 28, 1993
-------
The Pollutant Removal Capability of Pond and Wetland Systems: A Review
NOTK: T he table below provides summary data on the pollutant removal capability of nearly sixty stormwater pond and wetland systems. Each
study differs with respect to pond design, number of storms monitored, pollutant removal calculation technique, and monitoring
technique, so exact comparisons between studies are not appropriate.
Note: An asterisk (*) denotes an Inferred value
Table taken from Schueler et al, 1992
80040000H:\wp\final\postcon\append-b.tbl
B-23
Woodward-Clyde
January 28, 1993
-------
The Pollutant Removal Capability of Pond and Wetland Systems: A Review
TYPE
NO.
NAME
STATE
NO. OF
STORMS
WATER-
SHED
AREA
(Acre.)
TREAT-
MENT
VOL.
(In./Acrc)
rkmoval efficiency <%)
TSS
TP
SP
TN
N03
COD
Pb
Zn
OTHER
WET PONDS
7
Seattle
WA
5
0.75
86.7
78.4
64.4
65.1
65.2
Cu: 66.5
8
Boynton Beach
FL
8
91.0
76.0
87.0
TKN: 58.0
9
~race Street
MI
18
VB/VR=.52
32.0
12.0
6.0
(-1.0)
26.0
TKN: 7.0
BOD: 3.0
10
Pitt-AA
MI
6
4872.0
VB/VR=0.52
32.0
18.0
7.0
23.0
62.0
13.0
TKN: 14.0
BOD: 21.0
11
Unqua
NY
8
VB/VR=3.07
60.0
45.0
80.0
TOC: 7.0
12
Wavcrly Hills
MI
29
VB/VR=7.57
91.0
79.0
62.0
66.0
69.0
95.0
91.0
Cu: 57.0
TKN: 60.0
BOD: 69.0
13
Lake Ellyn
IL
23
VB/VR=10.70
84.0
34.0
78.0
71.0
Cu: 71.0
14
Lake Ridge
MN
20
315.0
0.08
A: 90.0
B: 85.0
61.0
37.0
11.0
8.0
41.0
24.0
10.0
17.0
73.0
52.0
TKN: 50.0
TKN: 28.0
15
West Pond
MN
8
76.0
0.15
65.0
25.0
61.0
8.0-79.0
66.0
TOC: 19.0
TKN: 23.0
Cr: 48.0-76.0
Cd: 12.0-91.0
16
McCarrons
MN
21
608.0
0.19
91.0
78.0
85.0
90.0
90.0
17
McKnight Basin
MN
20
725.0
0.22
A: 85.0
B 85.0
48.0
34.0
13.0
12.0
30.0
14.0
24.0
11.0
67.0
63.0
TKN: 31.0
TKN: 15.0
18
Monroe Street
WI
238.0
0.26
90.0
65.0
70.0
70.0
70.0
65 0
Cu: 75.0
FColi: 70.0
Pest: 25-50.0
Hydro: 75-90
19
Runaway Bay
NC
5
437.0
0.33
54.0
24.0
42.0
TKN: 20.0
Nole: An asterisk (•) denotes an Inferred value
Table taken from Schueleret al, 1992
80040000H:\wp\final\postcon\«ppend-b.tbl Woodward-Clyde
Januaiy 28, 1993
B-24
-------
The Pollutant Removal Capability of Pond and Wetland Systems: A Review
NO. OF
WATER-
SHED
TREAT-
MENT
RKMOVAL KI-TICIKNCV <%)
TYPE
NO.
NAME
STATE
STORMS
AREA
(Acres)
VOL.
(In ./Acre)
TSS
TP
SP
TN
N03
COD
Pb
Zn
OTHER
20
Buck] and
CT
7
20.0
0.40
61.0
45.0
22.0
18.0-59.0
51.0
Cd: < 0
TKN: 24.0
TOC: 33.0
Cu: 38.0
21
Highway Site
FL
13
41.6
0.55
65.0
17.0
21.0
7.0
41.0
37.0
22
Woodhollow
TX
14
381.0
0.55
54.0
46.0
39.0
45.0
41.0
76.0
69.0
TKN: 26.0
NH3: 28.0
BOD: 39.0
FColl: 46.0
23
SR 204
WA
5
1.8
0.60
99.0
91.0
69.1
88.2
87.0
Cu: 90.0
24
Farm Pond
VA
51.4
1.13
85.0
86.0
73.0
34.0
NH3: (-107.0)
25
Burke
VA
29
27.1
1.22
(-33.3)
39.0
77.0
32.0
21.0
84.0
38.0
WET PONDS
26
Weatleigh
MD
32
48.0
1.27
81.0
54.0
71.0
37.0
35.0
82.0
26.0
TKN: 27.0
(Cont'd)
27
Mercer
WA
5
7.6
1.72
75.0
67.0
76.9
23.0
38.0
Cu: 51.0
28
1-4
FL
6
26.3
2.35
54.0
69.0
97.0
41.0-94.0
69.0
TOC: 45.0
TKN: 68.0
Cd: 43.0-51.0
Cu: 66.0-81.0
29
Timber Creek
FL
9
122.0
3.IM
64.0
60.0
80.0
15.0
80.0
30
Maitland
FL
30-40
49.0
3.65
90.0
87.0
95.0
96.0
PP: 11.0
Cu: 77.0
NH3: 82.0
31
Lakeaide
NC
5
65.0
7.16
91.0
23.0
82.0
TKN: 6.0
Nolt: An asterisk (*) dmutes an Inferred vaJut
Table taken from Schueleret al, 1992
80040000H:\wp\fmal\poslcoo\append-b.tbl
B-25
Woodward-Clyde
Januaiy 28, 1993
-------
The Pollutant Removal Capability of Pond and Wetland Systems: A Review
TYPE
NO.
NAME
STATE
NO. OF
STORMS
WATER-
SHED
AREA
(Acres)
TREAT-
MENT
VOL.
(In./Acre)
REMOVAL rmCIENCV (%)
TSS
TP
SP
TN
N03
COD
Pb
Zn
OTHER
WET ED
32
- Uplands
ONT
5'„
860.0
82.0
VA V
69.0
< V.v
i ,
11;
vijv; •
V»\R.'
' > :.
"V.
FCoU: 97.0
33
f\Eajt Barr haven
ONTj
2139.0,
'jV"
' ¦ 's'i
^7\°*
* ''/Y
sh.'.--..
hi'- ¦'
'$0
-• I .
FColi: 56.0
34
Kennedy-Burnett
ONT
395.0 ,
: S,0-61
, 98.0
.
.79.0
• » n
¦i&dki
'f
•C V'
;s.39-0..
¦:!
21.0
BOD: , 36.0
FColl: 99.0
stormwater
WETLANDS
35
EWA3
IL
72.0
59.0
70.0
Fe: 41.0
36
EWA4
1L
76.0
55.0
42.0
Fe: 43.0
37
EWA5
IL
89.0
69.0
70.0
Fe: 50.0
38
EWA6
1L
98.0
97.0
95.0
Fe: 92.0
39
B31
WA
13
461.7
0.01
14 0
(-2.0)
4 0
40
PC 12
WA
13
214.8
0.03
56.0
(-2.0)
20.0
41
McCarrons
MN
21
608.0
0.31
87.0
36.0
24.0
79.0
68.0
42
Queen Anne's
MD
0.50*
65 0
39.0
44.0
23.0
55 0
NH4: 55 0
ON: (- 5.0)
PP: 7.2
43
Swift Run
MI
5
1207.0
0.60
85.0
3.0
29.0
80.0
2.0
82.0
BOD: 4.0
44
Tampa Office Pond
FL
3-8
6.3
0.61
64.0
55.0
65.0
34.0
ON: (-3.7)
45
Highway Site
FL
13
41.6
0.81
66.0
19.0
30.0
18.0
75.0
50.0
46
Palm Beach PGA
FL
2340.0
2.00*
50.0
62.0
33.0
NH3: 17.0
BOD: 35.0
TOC: 10.0
TKN: 16.0
ED WETLANDS
47
Benjamin Franklin
VA
' '< [, '
40.0
0.08 ,
62.0
,-y ^ ?
14.9
M-'iV
23.6
¦\ "V-
,60.0
;:7cV
. 3 '1 1
(-73.5)
i * . ¦ '
Cd: (-79.8)
NH3:0.0
TKN: 4.4
N«lf. An fcsttrUk (•) denotes an Inferred value
Table taken from Schueler et al, 1992
80040000H: \wp\final\postcon\append-b. tbl
B-26
Woodward-Clyde
January 28, 1993
-------
Table L LITERATURE RESEARCHED TO INVESTIGATE PERFORMANCE CHARACTERISTICS OF WETLANDS
Study
Location
Name/LD.
Detention Pood
/Wetland
Constructed
/Natural
Wetland
Classifies too
Martin and Smooc
1986
Orange County,
Florida
Onmge Couniy
Treatment System
detention pood
wetland
constructed
hardwood
cypress dome
Harper et *L
1986
Florida
Hidden Lake
wetland
natural
hardwood
swampland
Reddy etaL
1982
Orange Coonty,
Florida
Lake Apopka
wetland
constructed
f marsh
Blackburn et aL
1986
Palm Brirh.
Florida
Palm BcadiPGA
Treatment System
wetland
constructed
and natural
southern
marshland
Esry and Cairns
1988
Tallahassee,
Florida
Jadcaoo Lake
detention pood
wetland
constructed
southern
marshland
Brown* R.
1985
Twin Cities Metro
Area,
Minnesota
Twin Cities Metro
wetlands
natural
and
constructed
northern
peatland
Wotzka and Oberu
1988
Rooeville,
Mxcoeaou
McCarrons
Treatment System
detention pood
wetland
constructed
cattail marsh
HickoketaL
1977
Minnesota
Wayzau
wetland
natural
north cm
peailand
Barten
1987
Waseca,
Minnesota
Clear Lake
wetland
constructed
marsh
Taken from Woodward-Clyde, 1991
Woodward-Clyde
January 28, 1993
80040000H: \wp\finaI\postcon\append-b.thl
B-27
-------
Table L LITERATURE RESEARCHED TO INVESTIGATE PERFORMANCE CHARACTERISTICS OF WETLANDS
Study
Location
Name/LD.
DrtrnHoo Pood
/Wetland
Constructed
/Natural
Wetland
Classifies ton
¦ i 11 i
Mdorin
1986
Fremont,
California
DUSTManfa
wetland
constructed
brackish marsh
Morris etaL
1981
Tafaoe
California
Taboe Basin
Meadowlaad
wetland
constructed
?
o
high elevation
riverine
Scbcrger and Davis
1982
Am Arbor,
Michigan
PmtftrM-Ann Arbor
Swift Ron
detention pood
wetland
constructed
and
natural
northern
peailand
ABAG
1979
Palo Alto,
California
Palo Aho Marsh
wetland
natural
brackish marsh
JoUy
1990
SL Agatha,
Maine
Long Lake Wetland-Pood
Treatment System
detention pood
wetland
constructed
citrail marsh
Oberts et al.
1989
Ramsey-Washington Tanners Lake, McKnighl
Metro Area, Lake, Lake Ridge, and
Minnesota Carver Ravine
detention poods
wetlands
constructed
rc»i| marsh
ReineltetaL
1990
King County,
Washington
B3I and PCI 2
wetlands
natural
palustrine
Rushloa and Dye
1990
Ttmp^
Florida
Tampa Office Pood
wetland
constructed
marsh
Hey and Barren
1991
Wadjworxh,
Illinois
Des Plaints River Wetland
Demonstration Project
wetland
constructed
freshwater
riverine
Taken from Woodward-Clyde, 1991
Woodward-Clyde
January 28, 1993
80040000H:\wp\final\postcon\«ppend-b.tbl
B-28
-------
Ttble 2. AVERAGE REMOVAL EFFICIENCIES FOR TOTAL SUSPENDED SOLIDS AND NUTRIENTS IN WETLANDS REPORTED IN THE LITERATURE
Studv
System Name
System Tvtje
Mirtin and Smoot
Orange County
detention pond •
1986
Treatment System
wetland •
entire ryrtem
Harper etal.
Hidden Lake
wetland
1986
Reddy etal.
Lake Apopka
rrjervoin
1986
flooded fleldi
Blackburn et al.
Palm Beach PGA
•yitera
1986
Treatment Syitem
Exry and Caimi
Jackson Lake
lyitan
1988
Brown
Fish Lake
wcllamVpond
1985
Lake Elmo
wetland
Lake Riley
wetland
Spring Lake
wetland
Wotzka and Obert
McCanons Wetland
detention pond *
1988
Treatment System
wetland *
«yitera
Hlckok etal.
Wayzau Wetland
wetland
1977
Barten
Clecr Lake
wetland
1987
Melorin
DUSTManh
1986
Basin A
wetland •
Basin B
wetland •
Basin C
wetland •
System
wetland
Morrii etal.
Angora Qtek
wetland
1981
Tallac Lagoon
wetland
Scherger and Davli
Pittafield-Ann Arbor
detention pond *
1982
Swift Run
wetland
ABAO
Palo Alto Marsh
wetland
1979
Jolly
Long Lake Wetland-Pond
entire lysicm
1990
Treatment System
Obcrti etal.
Tanners Lake
detention pond *
1989
McKirfghtLake
detention pondi *
Lake Ridge
wetland
Carver Ravine
wetland-pond fynem
Relnelt et al.
B3I
wetland
1990
PC12
wetland
Ruth ton and Dye
Tampa Office Pond
wetland
1990
Hey and Barrett
Dei Plalnei River Wetland
1991
EWA 3
wetland
EWA 4
wetland
EWA 5
wetland
EWA 6
wetland
Median pollutant efficiency for wetland rysterna (without *):
Negative removal efficiencies indicate net export In pollutant loads.
Taken from Woodward-Clyde, 1991
80040000H:\wp\final\postcon\append-b.tbl
POLLUTANT REMOVAL EFFICIENCY (PERCENT)
TSS VSS TN TKN Org. N NH3 NQ3 TP Ortho-P Pit. P COD BOD
65
66
89
60
60
85
19
21
36
17
23
39
60
54
61
-17
40
9
33
17
43
SI
2
28
76
-30
21
7
18
17
83
-1.6
•24
62
80
7
-109
81
4.8
-7.6
57.5
51.9
68.1
64.2
60.9
7J
75.1
16.7
50
16
17
33
62
35
96
76
37
70
90
78
95
SI
-20
78
80
20
-20
-20
38
20
-14
36
•36
7
11
0
50
25
-86
37
27
-43
-7
28
23
-30
-10
91
87
94
95
87
94
85
24
83
88
26
85
60
22
63
78
36
78
57
25
53
90
79
93
94
•44
78
76
25
55
54
52
40
63
40
51
76
22
-27
-1
-1
-8
-5
18
16
32
2
12
29
46
-4
36
58
65
28
37
68 -
-25
-46
-18
-57
54
36
•20
•88
20
33
50
35
5
-120
39
76
14
20
23
49
87
85
37
¦6
54
95
94
92
63
85
85
20
50
57
67
1
5
14
24
-6
7
15
28
•10
I
II
17
9
7
34
37
1
20
34
-5
-3
•14
12
8
I
14
56
4
20
-2
-2
64
-3.7
55
65
72
76
89
98
70
42
70
95
59
55
69
97
76
79
24
5
7
33
46
46
28
23
55
45
Woodward-Clyde
January 28, 1993
B-29
-------
Tabic 1 AVERAGE REMOVAL EFFICIENCIES FOR METALS AND OIL AND GREASE IN WETLANDS REPORTED IN THE LITERATURE
Martin andSmoot
Orange County
detention pond •
1986
Treatment System
wetland *
entire system
Harper et aL
Hidden Lake
wetland
1986
Rcddy ct aL
Lake Apopbi
reservoirs
1986
flooded fields
Blackburn et aL
Palm Beach POA
system
1986
Treatment System
Etry and Calm*
JacJuoh Lake
system
1988
Brown
Fiih Lake
wetland/pond
1985
Lake Elmo
wetland
LakeRJIcy
wetland
Spring Lake
wetland
Wotzka and Obcrt
McCarrooi Wetland
detention pond *
1988
Treatment System
wetland ~
system
HJckok et al.
Wayzata Wetland
wetland
1977
Barten
Clear Lake
wetland
1987
Mtiorin
DUSTManh
1986
Basin A
wetland •
Basin B
wetland •
Basin C
wetland •
System
wetland
Morris et a].
Angora Creek
wetland
1981
Tall ac Lagoon
wetland
Scherger and Davit
PiOifieki-Aim Arbor
detention pond *
1982
Swift Rtm
wetland
ABAO
Palo Alto Marsh
wetland
1979
Jolly
Long Lake Wetland-Pond
entire system
1990
Treatment System
Oberu et aL
Tanners Lake
detention pond *
1989
McKitighlLake
detention ponds *
Lake Ridge
wetland
Carver Ravine
wetland-pond system
Reinelt et aL
B3I
wetland
1990
PC12
wetland
Rushton and Dye
Tampa Office Pond
wetland
1990
Hey and Barren
Dei Plaincs River Wetland
1991
EWA3
wetland
EWA4
wetland
EWA 5
wetland
EWA6
wetland
Median pollutant efficiency for wetland systems (without *):
Negative removal efficiencies indicate net enpoit in pollutant loads.
Lead
Zinc
Copper
Cadmium
Nickel
Chromium
Oil and
total
dissolved
total
dissolved
uxal dissolved
toul dissolved
total dissolved
total dissolved
Oreasc
39
29
15
-17
73
54
56
75
83
70
70
65
53
56
41
57
40 29
71 79
70 70
73 75
85
68
90
94
30
27
83
18
61
S3
59
63
52
i
83
82
42
24
-29
42
34
63
42
80
67
-20
-60
17
-19
36
-12
11
26
35
47
13
66
32
•57
13
•23
61
40
29
69
79
48
70
70
75
-13
Taken from Woodward-Clyde, 1991
80040000H: \wp\final\postcon\append-b. tbl
B-30
Woodward-Clyde
January 28, 1993
-------
Table 4. WETLAND GEOGRAPHIC AND HYDRAULIC CHARACTERISTICS
Study
System Name
Watershed
Land Use
%
Lend Use
System
Type
Wetland Watershed Wedand/
Size Size Watershed
(acres) (acres) Ratio
Average
Flows
(cTs)
Basin
Volume
(acre-ft)
Detention
Time
(hours)
Depth
w
Inlet
Condition
Comments
Martin and Smoot
1986
Orange County
Treatment System
residential
highway
forest
33
27
40
detention pond
wetluid
rystrm
0.2
0.78
0.98
41.6
0.5%
1.9%
2.41
2.5
1.2-1.9
0.5-2.8
7J
8
8-11
0-5
discrete
discrete
• Short circuiting was observed during several storms.
Harper el al.
1986
Hidden Lake
residential
NA
wetland
Z5
55.2
4.5%
0.22
NA
NA
NA
diffuse
• The wetland is not a basin, but similar to a grassy iwaJe.
Reddy et a).
1982
Lake Apopka
agriculture
100
reservoirs
flooded fields
0.9
0.9
NA
NA
0J6
0.23
2.6
0.6
9.4 days
4.8 days
33
0.7
diffuse
• Design configuration suggest* little short circuiting occurred.
Dl&ckbum et al.
1986
Palm Beach POA
Treatment System
residential
golf course
NA
wetland
wetland
89
296
2350
3.8%
12.6%
NA
NA
NA
NA
diffuse
• Design configuration suggests Hole short circuiting occuncd.
• Generally sheet flow exists within the artificial wetland.
Ei ty and Caims
1988
Jackion Lake
urban
NA
detention pond
wetland
20
9
2230
1
o o
NO
* *
NA
150
13.5
NA
1JS
1J
diffuse
• Design configuration suggests little short circuiting occurred.
Brown
1985
Flih Lake
residential
commercial
agriculture
open
30
5
12
53
wetland
16
700
23%
0.001-0.01
64
NA
4
discrete
• The major influent to these natural wetlands is
discrete channelized flow.
• The schematic suggests large areas of dead storage.
Lake Elmo
residential
commercial
agriculture
open
12
34
53
wetland
225
2060
10.9%
0.001-0.65
900
NA
4
discrete
• Short circuiting was not discusied by the author.
Lake Riley
residential
commercial
agriculture
open
13
2
30
55
wetland
77
2473
3.1%
0.004-U5
231
NA
3
discrete
Spring Lake
residential
commercial
agriculture
open
5
37
wetland
64
5570
1.1%
0.008-4
256
NA
4
discrete
Wocka and Oben
1988
McCarrons Wetland
Treatment System
urban
NA
detention pond
wetland
system
Z47
6.2
1.67
600
0.4%
im>
1.4%
0.05-.2
24-9.7
24 days
13
diffuse
diffuse
• Three discrete inlets help to minimize short circuiting and
dissipate surface water energy.
Hickok et al.
1977
Wayzata Wetland
residential
commercial
NA
wetland
7.6
65.1
11.7%
0.08
NA
NA
NA
discrete
• Design configuration suggests minimal short circuiting
existed regardless of a single discrete inlet
Barten
1987
Gear Lake
urban
NA
wetland
32.9
1070
4.9%
U
10
3-5 days
0.5
diffuse
Mdorin
1986
DUST Marsh
urban
agriculture
93
7
wetland A
wetland B
wetland C
wetland (system)
5
6
21
32
2960
0.2%
0.2%
0.7%
1.1%
10-250
150
4-40 days
4.7
diffuse
• Design configuration suggests little short circuiting occurred
due to long and narrow wetland basins.
Morrit et al.
1981
Angora Creek
Tallac Lagoon
wetland
wetland
NA
NA
2816
2781
NA
NA
8.46
8.68
NA
NA
NA
NA
NA
NA
difftise
diffuse
• Plow occur* as channelized flow until the storm volume
is large enough to force sheet flow through the meadowlands.
Scherger and Davii
1982
Pitufield-Arm Arbor
Swift Run
residential
commercial
agriculture
open
45
19
13
23
detention pond
wetland
25.3
23 j
4872
1207
0.5%
2.1%
0-2916
0-166
21-176
15-60
4-105
12-82
0-6
0-3
discrete
discrete
• The schematic suggests large areas of dead storage exist
Taken from Woodward-Clyde, 1991
8(XM0000H:\wp\rmoI\p<»tooaVappend-b .tbl Woodward-Clyde
January 28, 1993
B-31
-------
Table 4. WETLAND GEOGRAPHIC AND HYDRAULIC CHARACTERISTICS (concluded)
Wetland Watershed Wetland/
Average
Bailn
Detertion
Watershed
%
System
Size
Size
Watershed
Fk>w«
Volume
Time
Depth
Inlet
Study
Syoem Name
LandUie
Land U*e
Type
(acre.)
(acres)
Ratio
W
(acre-ft)
(hours)
w
Condition
Comments
AJBAQ
Palo Alto Manh
residential
62
wetland
613
17600
33%
150-320
400-750
30
1-6
diicrete
• Water level and volume are controlled by the tidal cycle.
1979
commercial
12
• Channelized /low exist until the tide Increases earning
open
26
the surrounding manh to become Inundated.
Jolly
Long Lake Wetland-Pond agriculture
100
wetland-pond
1J
18
83%
aoi
1J
NA
0.5-8
diffuse
• Entire system consists of a sedimentation basin, grus niter
1990
Treatment System
strip, constructed wetland, and deep porxi.
Oberti et al.
Tanners Lake
residential
NA
pond
0.07
1134
negligible
NA
0.1
NA
3.0
discrete
• Monitoring occurred during a dry period.
1989
McKnightLake
residential
NA
pond
5J3
5217
0.1%
NA
13.2
NA
4.9
discrete
Lake Ridge
residential
NA
wetland
0.94
531
02%
NA
2.0
NA
4.8
dJaerete
Carver Ravfrie
realdentlal
NA
wetland-pond
037
170
0.2ft
NA
1-0
NA
Z0
discrete
Relneh et al.
B3I
urbanized
NA
wetland
4.9
461.7
1.1%
1.5
0.03-0.43
3.3
NA
discrete
• Storm flows redoce detention times.
1990
PC12
rural
NA
wetland
3.7
214.8
1.7*
0.7
0.05-0.60
2.0
NA
discrete
• Channelization reduced effective area In wetland
Rushton and Dye
Tampa Office Pood
commercial
100
wetland
035
63
5.6ft
NA
032
NA
0-1.5
diicrete
• Overflow from adjacent wetlands occurred during extremely
1990
hi ah water; leak and breach problems occurred during study.
Hey and Barrett
Dei Plainei River Wetland
NA
NA
EWA3
5.6
-
-
5
NA
NA
1
discrete
• Water Is pumped to the system from the river (drainage area
1991
Deuioiuuaiion Project
NA
NA
EWA4
S.6
•
•
0.6
NA
NA
1
dJterete
of 210 square miles) for 20 hours per week.
NA
NA
EWAS
4.5
-
-
4
NA
NA
1
diicrete
NA
NA
EWA 6
8.3
•
-
1
NA
NA
1
diicrete
NA a Not available
Taken from Woodward-Clyde, 1991
80040000H:\wp\final\postcon\append-b.tbl
B-32
Woodward-Clyde
January 28, 1993
-------
Table 5. SAMPLING CHARACTERISTICS FROM THE WETLANDS REVIEWED
Number
Studv
Location
Time
of Stndv
Length of
Stndv
Type of
Samule
of Storms
Monitored
Method of Computing
Efficiencies
Mirtin and Smooc
1986
Orange County,
Florida
1982-1984
2 years
7 main gisb
6 compost*
13
ROL
Harper etaL
1986
Florida
1984-1985
1 year
composite
18
ER
ReddyetaL
1982
Orange County,
Florida
1977-1979
2years
gxmb
-150
MC
Blackburn a tL
1986
Palm Beach,
Florida
1985
1 year
tingle gnb
36
MC
Eny and Caims
1988
Tallahassee,
Florida
1985
NA
NA
1
NA
Brawn
1985
Twin Cities
Metro Area,
Minnesota
1982
1 year
5-7
SOL
Wouka and Obens
1988
Roaeville,
Minnesota
1984-1988
2 yean
25
ROL
HidcoketaL
1977
Minnesota
1974-1975
10 months
NA
NA
SOL
Banen
1987
Waseca,
Minnesota
1982-1985
3 years
27
BR
Mcorin
1986
Coyote Hilly
Fremoat,Ca.
1984-1986
2 yean
11
SOL
Morris a aL
1981
Taboe Basin,
California
1977-1978
1 year
r'nglr grab
-75
MC
Schergcr and Davii
1982
Ann Arbor,
Michigan
1979-1980
8 months
oompocrie
7
SOL
ABAG
1979
Palo Alio,
California
1979
3 months
8
ER
Jolly
1990
Sl Agatha,
Maine
1989
5 months
mmpneiv.
11
SOL
Oberts et aL
1989
Ramaey-Wadimgum
Metro Area,
Minnesota
1987-1989
2 yean
compocoe
7-22
SOL
Rjcinelt ct aL
1990
KmgCowty,
Washington
1988-1990
2 years
composite
13
SOL
Rush too and Dye
1990
Tampa,
Florida
1989-1990
12 months
composite
3-8
ER
Hey and Banea
1991
Wadawotth,
Illiixjil
1990
8 months
discrete
continuous
SOL
Table Notes;
ER «* Event mean ooaceatratioa
SOL = Sum of event loads
ROL = Regression of event loads
MC =t Mean ooacentrmnoa
NA = Not available
Taken from Woodward-Clyde, 1991
80040000H:\wp\fuul\po3tcon\append-b.tb] Woodward-Clyde
January 28, 1993
B-33
-------
NOTATION
BAC: Bacteria
BOD: Biological Oxygen Demand
Cd: Cadmium
COD: Chemical Oxygen Demand
Cr: Chromium
Cu: Copper
FCol: Fecal Coli
Fe: Iron
N: Nutrients
NH3: Ammonia
NN: Nitrate/Nitrite
N03: Nitrate
OD: Oxygen Demand
ON: Organic Nitrogen
OP: Ortho-Phosphorus
Pb: Lead
SP: Soluble Phosphorus
TDS: Total Dissolved solids
TKN: Total Kgeldahl Nitrogen
TM: Trace Metals
TN: Total Nitrogen
TOC: Total Organic Carbon
TP: Total Phosphorus
TS: Total Solids
TSS: Total Suspended Solids
Zn: Zinc
NA: NOT AVAILABLE
80040000H:\wp\final\postcon\append-b.tbl
B-34
Woodward-Clyde
January 28, 1993
-------
COMPUTER RUNS TO DETERMINE REMOVAL EFFICIENCY OF
INFILTRATION BASINS AND TRENCHES IN VARIOUS REGIONS
8(XM0000H:\wp\final\postcon\append-b.ttil Woodward-Clyde
January 28, 1993
B-35
-------
PACIFIC NORTHWEST
Perc.
Mean Coef, of Variation
Volume 0.5 1.09
Intensity 0.035 0.73
Duration 15.9 ¦ 0.8
Interval 123 1.5
Area= 1 ac
Rv= 0.5
Volume= 90% ave runoff 817 cf
(0.23 in. runoff) (1 ac * 0.50 * 0.50 in * 90%)
QR VR
63.525 907.5
Height
Surf. Area
* Fig 4*
*Fig 1*
*Fig
3
(in/hr)
M
(sq. ft.)
QT
QT/QR
VB
VB/VR
E
VE/VR
% FLOW
%
VOL
% REMOVA
8.27
2
408.4
281.4
4.43
816.8
0.9
38.1
0.9
100
58.0
100.0
2.41
3.2
255.2
51.3
0.81
816.8
0.9
6.9
0.9
66
58.0
85.7
2.41
8
102.1
20.5
0.32
816.8
0.9
2.8
0.9
31
58.0
71.0
1
1.2
680.6
56.7
0.89
816.8
0.9
7.7
0.9
68
58.0
86.6
1
2
408.4
34.0
0.54
816.8
0.9
4.6
0.9
48
58.0
78.2
1
5
163.4
13.6
0.21
816.8
0.9
1.8
0.8
19
55.0
63.6
0.5
3
272.3
11.3
0.18
816.8
0.9
1.5
0.8
16
55.0
62.2
0.27
8
102.1
2.3
0.04
816.8
0.9
0.3
0.3
0
23.0
23.0
Computed from Woodward-Clyde, 1986
80040000H:\wp\final\postcon\append-b.tbl Woodward-Clyde
January 28, 1993
B-36
-------
PACIFIC SOUTH
Perc.
Mean Coef. of Variation
Volume 0.54 0.98
Intensity 0.054 0.76
Duration 11.6 0.78
Interval 476 2.09
Area= 1 ac
Rv= 0.5
Volume = 90% ave runoff 871 cf
(0.24 in. runoff) (1 ac * 0.50 * 0.54 in * 90%)
OR VR
98.01 980.1
.
Height
Surf. Area
* Fig 4*
*Fig 1*
* Fig 3
fin/hr)
im
(sq. ft.)
QT
QT/QR
VB
VB/VR
E
VE/VR
% FLOW
% VOL
% REMOVA
8.27
2
435.6
300.2
3.06
871.2
0.9
145.8
0.9
100
58.0
100.0
2.41
3.2
272.3
54.7
0.56
871.2
0.9
26.6
0.9
50
58.0
79.0
2.41
8
108.9
21.9
0.22
871.2
0.9
10.6
0.9
21
58.0
66.8
1
1.2
726.0
60.5
0,62
871,2
0.9
29.4
0.9
54
58.0
80.7
1
2
435.6
36.3
0.37
871.2
0.9
17.6
0.9
36
58.0
73.1
1
5
174.2
14.5
0.15
871.2
0.9
7.1
0.9
15
58
64.3
0.5
3
290.4
12.1
0.12
871,2
0.9
5.9
0.9
12
58
63.0
0.27
8
108.9
2.5
0,03
871,2
0.9
1.2
0.8
0
50.0
50.0
Computed from Woodward-Clyde, 1986
80040000H: \ wp\final\postcon\append-b. tbl
B-37
Woodward-Clyde
January 28, 1993
-------
EAST GULF
Mean Coef. of Variation
Volume
0.8
1.19
Intensity
0.178
1.03
Duration
6.4
1.05
Interval
130
1.25
Area =
1 ac
Rv=
0.5
Volume =
90% ave runoff
1307
cf
(0.36 in. runoff)
(1 ac * 0.50
* 0.80 in * 90%)
QR
VR
323.07
1452
* * *
* * *
Perc.
Height
Surf. Area
* Fig 4*
*Fig 1*
* Fig 3
Rate (in/hr)
M '
(sq. ft.)
QT
QT/QR
VB VB/VR
E VE/VR
% FLOW
% VOL
% REMOVA
8.27
2
653.4
450.3
1.39
1306.8 0.9
40.3 0.9
72
55.0
87.4
2.41
3.2
408.4
82.0
0.25
1306.8 0.9
7.3 0.9
23
55.0
65.4
2.41
8
163.4
32.8
0.10
1306.8 0.9
2.9 0.9
8
55.0
58.6
1
1.2
1089.0
90.8
0.28
1306.8 0.9
8.1 0.9
24
55.0
65.8
1
2
653.4
54.5
0.17
1306.8 0.9
4.9 0.9
18
55.0
63.1
1
5
261.4
21.8
0.07
1306.8 0.9
2.0 0.8
0
50.0
50.0
0.5
3
435.6
18.2
0.06
1306.8 0.9
1.6 0.8
0
50.0
50.0
0.27
8
163.4
3.7
0.01
1306.8 0.9
0.3 0.2
0
18.0
18.0
omputed from Woodward-Clyde, 1986
80040000H:\wp\final\postco(i\append-b tbl
Woodward-Clyde
B-38 Januaiy 28, 1993
-------
MID-ALTLANTIC
Mean Coef. of Variation
Volume 0.64 1.01
Intensity 0.092 1.2
Duration 10.1 0.84
Interval 143 0.97
Area =
Rv =
Volume =
1 ac
0.5
90% ave runoff
(0.29 in. runoff)
1 053 cf
(1 ac * 0.50 * 0.64 in * 90%)
Perc.
OR
VR
1 66.98
1161.6
* * *
Height
Surf. Area
fln/hr)
M
(sq. ft.)
Q1
QT/QR
V8
8.27
2
526.4
362.7
2.17
1052.7
8.27
5
210.5
145.1
0.87
1052.7
8.27
8
131.6
90.7
0.54
1052.7
2.41
3.2
329.0
66.1
0.40
1052.7
2.41
8
131.6
26.4
0.16
1052.7
1
1.2
877.3
73.1
0.44
1052.7
1
2
526.4
43.9
0.26
1052.7
1
5
210.5
17.5
0.11
1052.7
0.5
3
350.9
14.6
0.09
1052.7
0.27
2
526.4
11.8
0.07
1052.7
0.27
5
210.5
4.7
0.03
1052.7
0!27
8
131.6
3.0
0.02
1052.7
V8 VB/VR
'Fig 4*
VE/VR
* Fig 1*
% FLOW
* Fig 3
% VOL
% REMOVAl-
0.9
44.7
0.9
81
58.0
92.0
0.9
17.9
0.9
51
58.0
79.4
0.9
11.2
0.9
35
58.0
72.7
0.9
8.1
0.9
30
58.0
70.6
0.9
3.3
0.9
13
58.0
63.5
0.9
9.0
0.9
33
58.0
71.9
0.9
5.4
0.9
19
58.0
66.0
0.9
2.2
0.9
7
58.0
60.9
0.9
1.8
0.9,
0
58.0
58.0
0.9
1.5
0.8
0
53.0
53.0
0.9
0.6
0.5
0
39.0
39.0
0.9
0.4
0.3
0
25.0
25.0
Computed from Woodward-Clyde, 1986
80010000H: \wp\finaI\postcon\append-b.tbl
B-39
Woodward-Clyde
Januaiy 28, 1993
-------
VEGETATIVE FILTER STRIP REMOVAL EFFICIENCY CHART
Wood ward-Clyde
80040000HAwp\final\postcon\append-b.tbl January 28, 1993
B-40
-------
50-
40-
30-
20-
10-
i0*
40%
0.04
0.08
0.12 0.16 0.20
AVERAGE FLOW DEPTH ( FT.)
0.24
0.28
Virginia Channel - Mean Runoff Event
Florida Channel • Mean Runoff Event
Taken from Hartigan et al, 1989
80040000H:\wp\fmal\postcon\append-b.tbl
B-41
Woodward-Clyde
January 28, 1993
-------
Taken from IEP, Inc. 1991
80040000H:\wp\final\postcon\append-b.tbI
0.3 0.4 0 5 0.6 0.7
BUFFER AREA/ IMPERVIOUS AREA
C I
B-42
Woodward-Clyde
January 28, 1993
-------
APPENDIX C
COST DATA
-------
BMP CONSTRUCTION COST ESTIMATES
(Cost include construction costs only, exclude land, engineering, etc.)
INFILTRATION BASIN
INFILTRATION BASIN- Washington, D.C. (based on equation from regression analysis from bids for
for 53 ponds and taking out 50% of outlet cost; Wiegand et al, 1986
C=3.05*V~0.75
Storage
Total
Annual
Volume
Cost
Cost/Cu. Ft.
Maint. Cost
(cu. ft.)
(1988 S)
($/cu. ft.)
(% caDital cost)
10,000
3,146
0.31
3-5%
20,000
5,290
0.26
3-5%
30,000
7,170
0.24
3-5%
40,000
8,897
0.22
3-5%
50,000
10,518
0.21
3-5%
60,000
12,059
0.20
3-5%
70,000
13,537
0.19
3-5%
80,000
14,963
0.19
3-5%
90,000
16,345
0.18
3-5%
100,000
17,689
0.18
3-5%
Note: Cost estimates from Schueler et al, 1985 were not used since
and updates
INFILTRATION BASIN- Oconomowoc, Wisconsin (estimated for 3 foot deep infiltration basin)
Storage Total Annual
Volume Cost Cost/Cu. Ft. Maint. Cost
feu, ft.) (1988 $) ($/cu. ft.) (% capital cost)
NA NA 1.18 13%
80040000\123\report
C-1
January 29, 1993
-------
INFILTRATION BASINS- Southeastern Wisconsin (estimated from graphs calculated from unit costs); SWRPC, 1991
Storage
Total
Annual
Volume
Cost
Cost/Cu. Ft.
Maint. Cost
(cu. ft.)
(1988 $)
($/cu. ft.)
(% capital cost)
30,000
22,000
0.73
5%
50,000
30,000
0.60
4%
75,000
38,000
0.51
3%
100,000
44,000
0.44
3%
250,000
110,000
0.44
3%
500,000
210,000
0.42
3%
750,000
300,000
0.40
3%
1,000,000
340,000
0.34
3%
80040000\123\report
C—2
January 29, 1993
-------
CHART 1. UNIT CONSTRUCTION COST AND TOTAL ANNUAL COST OF INFILTRATION BASIN
INFILTRATION BASIN
TOTAL ANNUAL COST/CU FT STORAGE
10.000
S lorn tie. cu.ft.
100,00-)
O
O
c
o
c
o
CJ
c
D
0.1
1000
INFILTRATION BASIN
COST/CU FT STORAGE
10000
100000
Storage, cu. fL
1000000
10000000
80040000\123\report
C-3
January 29, 1993
-------
INFILTRATIONTRENCH
INFILTRATION TRENCH - Washington, D.C. (based on equation from regression analysis from bids for
7 trenches); Wiegand, et.al., 1986
C=26.55* Vs 0.63 V= volume of void space
Storage Total Annual
Volume Cost Cost/Cu. Ft. Maint. Cost
(cu. ft.) (1988 $) ($/cu. ft.) (% capital cost)
300
996
3.32
NA
500
1,373
2.75
NA
750
1,773
2.36
NA
1,000
2,125
2.13
NA
2,000
3,289
1.64
NA
3,000
4,247
1.42
NA
4,000
5,090
1.27
NA
5,000
5,859
1.17
NA
6,000
6,572
1.10
NA
7,000
7,242
1.03
NA
8,000
7,878
0.98
NA
9,000
8,485
0.94
NA
10,000
9,067
0.91
NA
SURFACE INFILTRATION TRENCH- Washington, D.C.; Macal, et.al., 1987
Storage Total Annual
Volume Cost Cost/Cu. Ft. Maint. Cost
(cu. ft.) (1988 $) ($/cu. ft.) (% capital cost)
NA NA NA 5-10%
80040000\123\report
C—4
January 29, 1993
-------
UNDERGROUND INFILTRATION TRENCH - Washington, D.C.; Macal, et.al., 1987
Storage Total Annual
Volume Cost Cost/Cu. Ft. Maint. Cost
(cu. ft.) (1988 $) ($/cu. ft.) (% capital cost)
NA NA NA 10-15%
INFILTRATION TRENCH- Wisconsin (estimated from graphs calculated from unit costs, assumed
storage volume equals 40% total volume); SE Wise. Reg. Planning Comm., 1991
Storage
Total
Annual
Volume
Cost
Cost/Cu. Ft.
Maint. Cost
(cu. ft.)
(1988 $)
($/cu. ft.)
(% capital cost)
Comments
198
1,815
9.17
7%
5'x3'x33'
304
1,805
5.94
5%
5'x8'x19'
300
2,750
9.17
7%
5'x3'x50
2004
12,525
6.25
7%
10'x3'x167'
2016
9,450
4.69
5%
10'x8'x63'
3996
21,756
5.44
6%
15'x3'x222'
3984
16,600
4.17
6%
15'x8'x83
9600
40,000
4.17
6%
15'x8'x200'
80040000\123\report
C —5
January 29, 1993
-------
INFILTRATION TRENCH - (based on equation); Kuo, et.al., 1988
cost= 1.28* (0.68* (w*/* (d +1))+0.28*((w*l) + (w*d) + (l*w))+2.5*(d+1) + 0.04*((20+w) + (40+1))
Storage Total Annual
Volume Cost Cost/Cu. Ft. Maint. Cost
(cu. ft.) (1988$) ($/cu. ft.) (% capital cost) Comments
5'x2'x20'
5'x3'x33'
5'x8'x13'
5'x3'x50'
5'x8'x19'
s'xs'xer
5'x8'x25'
10'x3'x167'
5'x3'x125'
10'x4'x250'
10'x8'x125'
80
364
4.55
NA
198
768
3.88
NA
234
799
3.41
NA
300
1,145
3.82
NA
304
1,013
3.33
NA
402
1,521
3.78
NA
400
1,306
3.27
NA
3,004
6,806
2.27
NA
750
2,805
3.74
NA
4,000
12,844
3.21
NA
4,000
11,879
2.97
NA
80040000\123\report
C—6
January 29, 1993
-------
CHART 2. UNIT CONSTRUCTION COST AND TOTAL ANNUAL COST OF INFILTRATIONTRENCH
80040000\123\report
C—7
January 29, 1993
-------
VEGETATIVE BUFFER STRIP
GRASS BUFFER STRIP- Washington, D.C.; Schueler, 1987
1988 Annual
Establishmen
Area
Cost/ac.
Maint. C
Method
(acres)
($/ac.)
(% capital
Hydroseedin<
1-2
2,024
NA
Hydroseedin<
2-5
1,793
NA
Hydroseedinc
5+
1,486
NA
Conventional
1-2
1,845
NA
Conventional
2-5
1,691
NA
Conventional
5+
1,486
NA
Conventional
1-2
8,686
NA
blanket or net
Sodding
1-2
11,171
NA
FOREST BUFFER STRIP- Washington, D.C.; Schueler, 1987
1988
Cost/acre
i&acl
Conifers- seedlings
Deciduous- seedlings
Nursery stock- inexpensive species
Nursery stock- expensive species
102
205
1,025
5,124
Annual
Maint. Cost
(% capital cost)
NA
NA
NA
NA
80040000\123\report
C—8
January 29, 1993
-------
MARSH BUFFER STRIP- Washington, D.C.; Schueler, 1987
1988 Annual
Cost/acre Maint. Cost
($/ac.) (% capital cost)
Rhizomes, plugs or small pots 2,050 NA
SOD GRASS FILTER STRIPS- Wisconsin (estimated from graphs calculated from unit costs);
SE Wise. Reg Planning Comm., 1991
Annual
Cost/acre Maint. Cost
($/ac.) (% capital cost)
40' Wide VFS 27,200 3%
60' Wide VFS 25,400 3%
80' Wide VFS 24,500 3%
100'Wide VFS 25,700 3%
80040000\123\report C-9 January 29, 1993
-------
SWALES
GRASS SWALES- 15 ft wide, 3:1 sideslope (approx. 2.5 ft deep)- Washington, D.C.; Schueler, 1987
Excavation/shaping plus:
Seeding/straw mulching
Seeding/net anchoring
Sodding/stapling
1988
Cost/linear ft.
($/linear ft)
4.61
8.45
7.94
Comments
more economical
than the curb and
gutter they replace
SODDED GRASS SWALES- Wisconsin (cost estimated from graph calculated from unit costs);
SE Wise. Reg. Planning Comm., 1991
1988
Cost/linear ft.
(S/lin ft)
1" bottom, 1' deep 9
10'bottom, 1'deep 15
1' bottom, 3' deep 20
10' bottom, 3' deep 28
1' bottom, 5' deep 40
10' bottom, 5' deep 50
80040000\123\report
C-10
January 29, 1993
-------
POROUS PAVEMENT
Cost presented are Incremental Costs, ie. cost beyond that required for conventional asphalt pavement
POROUS PAVEMENT - Wisconsin (Based on unit costs); SWRPC, 1991
Incremental Capital Cost/Ac
(Incremental costs, i.e. cost beyond
that required for conventional asphalt
pavement.)
Low
Cost/Ac
$40,051
High
Cost/Ac
$78,288
Moderate Annual
Cost/Ac Maint. Cost
$59,169 $200/ac/yr*
incremental O&M costs( includes
vacuum sweeping, high-pressure
jet hosing and inspections)
POROUS PAVEMENT - Washington, D.C. (Based on unit costs); Schueler, 1987
Incremental
Capital Cost/Ac
Low
Cost/Ac
NA
High
Cost/Ac
NA
Moderate
Cost/Ac
$76,916
Annual
Maint. Cost
NA
Comment
Economy of scale not evident
80040000\123\report
C-11
January 29, 1993
-------
CONCRETE GRID PAVEMENT
Cost presented are Incremental Costs, ie. cost beyond that required for conventional asphalt pavement
CONCRETE GRID PAVEMENT - National Concrete Masonry Association (Based on unit costs)
Incremental
Capital Cost/Ac
Low High
Cost/Ac Cost/Ac
NA
NA
Moderate
Cost/Ac
$65,340
Annual
Maint. Cost
NA
Comment
ave. incremental costs are between
$ 1.00 to $2.00 per sq. ft.
CONCRETE GRID PAVEMENT - Smith, 1981
Incremental
Capital Cost/Ac
Low
Cost/Ac
NA
High
Cost/Ac
NA
Moderate
Cost/Ac
Annual
Maint. Cost
$43,560 -$1,900*
Comment
ave. incremented costs are about
$ 1.00 per sq. ft.
*there is a net decreased in operation
and management cost for concrete
pavements with life span of 20 years
80040000\123\report
C—12
January 29, 1993
-------
FILTRATION BASINS
SEDIMENTATION/FILTRATION BASINS- Austin, Texas (engineer's estimates); Tull, 1990
Storage
Drainage
Total
Annual
Volume
Area
Cost
Cost/Cu.Ft.
Cost/Acre
Maint. Cost
(cu. ft.)
(acres)
(1988)
($/cu.ft.)
($/ac.)
1% capital cost)
1,815
1
13,613
7.50
13,613
NA
1,815
1
19,058
10.50
19,058
NA
3,630
2
16,880
4.65
8,440
NA
3,630
2
19,602
5.40
9,801
NA
9,075
5
25,682
2.83
5,136
NA
18,150
10
38,115
2.10
3,812
NA
27,225
15
46,283
1.70
3,086
NA
36,300
20
54,450
1.50
2,723
NA
54,450
30
70,785
1.30
2,360
NA
80040000\123\report
C-13
January 29, 1993
-------
CHART 3. UNIT CONSTRUCTIONCOST AND TOTAL ANNUAL COST OF FILTRATION BASIN
Storage, cu. ft.
80040000\123\report
C—14
January 29, 1993
-------
WATER QUALITY INLETS/ CATCH BASINS
3 Chamber Water Quality Inlet (Oil/Grit Separator); Schueler, 1987
Storage Annual
Volume Maint. Cost
(cu.ft.) Cost.$ (% capital cost) Comments
NA 7,500 NA ave= $ 7,000 to
$ 8,000
3 Chamber Water Quality Inlet (Oil/Grit Separator) - Montgomery County, Maryland
Storage
Volume
fcu.ft.)
NA
Cost/Acre
$/ac.
17,500
Annual
Maint. Cost
(% capital cost)
NA
Comments
ave= $ 15,000 to
$ 20,000 per acre
Water Quality Inlet (Catch Basin with Sand Filter) - Shaver, 1991
Storage
Volume
fcu.ft.)
NA
1988 Annual
Cost/Acre Maint. Cost
$/ac. (% capital cost)
10,000 NA
Comments
located in 1986,
Maryland
80040000\123\report
C-15
January 29, 1993
-------
Water Quality Inlet (Catch Basin) - Wisconsin, 1991
Storage Annual
Volume Maint. Cost
(cu.ft.) Cost,$ (% capital cost)
NA 3,000 NA
Water Quality Inlet (Catch Basin) - Austin, Texas
Storage Annual
Volume Maint. Cost
(cu.ft.) Cost.$ (% capital cost)
NA 1,150 NA
80040000\123\report C-
Comments
None
Comments
ave= $ 900 to
$1,400, cost of
standard inlets
January 29, 1993
-------
DRY PONDS
DRY PONDS- Chester County,
Storage Drainage
Volume Area
(cu. ft.) (acres)
65,340 19
91,480 30
222,200 72
335,400 35
APWA Res. Foundation
Total
Cost Cost/Cu. Ft.
(1988 $) ($/cu. ft.)
20,035 0.31
16,695 0.18
26,713 0.12
18,946 0.06
DRY PONDS
- Fairfax, Virginia; APWA Res. Foundation
Storage
Drainage
Total
Volume
Area
Cost
Cost/Cu. Ft.
(cu. ft.)
(acres)
(1988 $)
($/cu. ft.)
6,530
8
12,018
1.84
13,940
36
11,985
0.86
15,250
11
7,673
0.50
16,120
18
5,031
0.31
25,260
16
9,412
0.37
28,310
12
11,847
0.42
37,900
227
7,899
0.21
48,790
43
12,269
0.25
70,570
25
6,855
0.10
94,960
55
15,107
0.16
104,110
32
6,913
0.07
112,820
20
12,142
0.11
253,080
94
20,232
0.08
382,020
99
50,050
0.13
80040000\123\report
Cost/Acre
($/ac.)
1,033
557
370
541
Cost/Acre
1448
337
731
287
592
982
35
286
278
276
218
611
215
507
17
January 29, 1993
-------
DRY PONDS- Washington, DC (based on WASHCOG NURP equation from
approx. 30 dry ponds) EPA, 1983
C=77.4*V~0.51
regression analysis for
Storage
Drainage
Total
Volume
Area
Cost
Cost/Cu. Ft.
Cost/Acre
(cu. ft.)
(acres)
(1988 $)
($/cu. ft.)
($/ac.)
1,000
NA
3,217
3.22
NA
5,000
NA
7,311
1.46
NA
7,500
NA
8,991
1.20
NA
10,000
NA
10,411
1.04
NA
25,000
NA
16,613
0.66
NA
50,000
NA
23,658
0.47
NA
75,000
NA
29,093
0.39
NA
100,000
NA
33,691
0.34
NA
250,000
NA
53,760
0.22
NA
500,000
NA
76,557
0.15
NA
750,000
NA
94,143
0.13
NA
1,000,000
NA
109,021
0.11
NA
Annual
Maint. Cost
(% capital cost)
3-5%
3-5%
3-5%
3-5%
3-5%
3-5%
3-5%
3-5%
3-5%
3-5%
3-5%
3-5%
80040000\123\report
C—18
January 29, 1993
-------
CHART 4. UNIT CONSTRUCTION COST AND TOTAL ANNUAL COST OF DRY POND
DRY POND
TOTAL ANNUAL COST/CU FT STORAGE
1,000
Storage cu.ft.
1,000,000
0.01
100
1000
DRY PONDS
COST/CU FT STORAGE
10000 100000
Storage, cu. fL
1000000 10000000
80040000\123\report
C-19
January 29, 1993
-------
ALL PONDS >10,000 cu. ft. and < 100,000 cu. ft. - Washington, D.C. (Based on equation from regression analysis
from bids for 53 ponds); Wiegand, et.al., 1986
C=6.11*V~0.752
Storage
Drainage
Total
Annual
Volume
Area
Cost
Cost/Cu. Ft.
Cost/Acre
Maint. Cost
feu. ft.)
(acres)
(1988 $)
($/cu. ft.)
($/ac.)
(% capital cost)
10,000
NA
6,419
0.64
NA
5%
20,000
NA
10,810
0.54
NA
5%
30,000
NA
14,663
0.49
NA
5%
40,000
NA
18,205
0.46
NA
5%
50,000
NA
21,531
0.43
NA
5%
60,000
NA
24,695
0.41
NA
5%
70,000
NA
27,730
0.40
NA
5%
80,000
NA
30,659
0.38
NA
5%
90,000
NA
33,498
0.37
NA
5%
100,000
NA
36,260
0.36
NA
5%
MALLONSITE DETENTION PONDS-
- Orlando, Florida; APWA Res. Foundation
Storage
Drainage
Total
Annual
Volume
Area
Cost
Cost/Cu. Ft.
Cost/Acre
Maint. Cost
feu. ft.)
(acres)
(1988 $)
($/cu. ft.)
($/ac.)
(% caDital cost)
18,000
NA
14,400
0.80
NA
NA
160,000
NA
84,800
0.53
NA
NA
250,000
NA
75,000
0.30
NA
NA
500,000
NA
105,000
0.21
NA
NA
1,000,000
NA
140,000
0.14
NA
NA
80040000\123\report
C-20
January 29, 1993
-------
4 DETENTION PONDS AND INTERCONNECTING PIPE - Wisconsin; APWA Res. Foundation
Storage Drainage Total Annual
Volume Area Cost Cost/Cu. Ft. Cost/Acre Maint. Cost
(cu. ft.) (acres) (1988$) ($/cu. ft.) ($/ac.) (% capital cost)
392,040 55 158,689 0.40 2,885 NA
80040000\123\report
C-21
January 29, 1993
-------
WET PONDS
WET PONDS- Chester County, Penn.; APWA Res. Foundation
Storage
Volume
(cu.ft.)
161,170
174,240
1,002,000
Drainage
Area
(acres)
12
275
174
Total
Cost
(1988 $)
8,348
61,339
98,143
Cost/Cu. Ft.
($/cu. ft.)
0.05
0.38
0.56
Cost/Acre
(S/ac.)
720
223
564
Annual
Maint. Cost
(% capital cost)
NA
NA
NA
WET PONDS- Fairfax, Virginia; APWA Res. Foundation
Storage
Drainage
Total
Volume
Area
Cost
Cost/Cu. Ft.
Cost/Acre
(cu. ft.)
(acres)
(1988 $)
($/cu. ft.)
($/ac.)
NA
12
10,201
NA
823
NA
13
4,626
NA
349
NA
17
1,695
NA
102
NA
27
20,677
NA
768
98,880
56
7,371
0.07
132
115,430
57
7,861
0.07
139
NA
105
4,979
NA
47
Annual
Maint. Cost
(% capital cost)
NA
NA
NA
NA
NA
NA
NA
80040000\123\report
C—22
January 29, 1993
-------
ALL PONDS >10,000 cu. ft. and < 100,000 cu. ft.- Washington, D.C. (based on equation from regression analysis
from bids for 53 ponds); Wiegand, et.al., 1986
C=6.11*V~ 0.752
Storage
Drainage
Total
Annual
Volume
Area
Cost
Cost/Cu. Ft.
Cost/Acre
Maint. Cost
(cu. ft.)
(acres)
(1988$)
($/cu. ft.)
($/ac.)
(% capital cost)
10,000
NA
6,419
0.64
NA
NA
20,000
NA
10,810
0.54
NA
NA
30,000
NA
14,663
0.49
NA
NA
40,000
NA
18,205
0.46
NA
NA
50,000
NA
21,531
0.43
NA
NA
60,000
NA
24,695
0.41
NA
NA
70,000
NA
27,730
0.40
NA
NA
80,000
NA
30,659
0.38
NA
NA
90,000
NA
33,498
0.37
NA
NA
100,000
NA
36,260
0.36
NA
NA
80040000\123\report
C —23
January 29, 1993
-------
WET PONDS > 100,000 cu. ft.- Washington, D.C. (based on equation from regression analysis from bids for 13 wet
ponds.); Wiegand, et.al., 1986
C=33.99*V~ 0.644
Storage
Drainage
Total
Annual
Volume
Area
Cost
Cost/Cu. Ft.
Cost/Acre
Maint. Cost
feu. ft.)
(acres)
(1988 $)
($/cu. ft.)
($/ac.)
(% capital cost)
100,000
NA
58,176
0.58
NA
NA
125,000
NA
67,167
0.54
NA
NA
150,000
NA
75,535
0.50
NA
NA
175,000
NA
83,418
0.48
NA
NA
200,000
NA
90,909
0.45
NA
NA
225,000
NA
98,073
0.44
NA
NA
250,000
NA
104,958
0.42
NA
NA
500,000
NA
164,014
0.33
NA
NA
750,000
NA
212,953
0.28
NA
NA
1,000,000
NA
256,297
0.26
NA
NA
10,000,000
NA
1,129,129
0.11
NA
NA
20,000,000
NA
1,764,440
0.09
NA
NA
30,000,000
NA
2,290,918
0.08
NA
NA
80040000\123\report
C—24
January 29, 1993
-------
WET PONDS - Washington, D.C.; Schueler, 1987
Storage Drainage Total Annual
Volume Area Cost Cost/Cu. Ft. Cost/Acre Maint. Cost
(cu. ft.) (acres) (1988 $) ($/cu. ft.) ($/ac.) (% capital cost)
NA NA NA NA NA 3-5%
SMALL ONSITE DETENTION PONDS- Orlando, Florida (in text and estimated off graph); APWA
Res. Foundation
Storage
Drainage
Total
Annual
Volume
Area
Cost
Cost/Cu. Ft.
Cost/Acre
Maint. Cost
(cu. ft.)
(acres)
(1988 $)
($/cu. ft.)
($/ac.)
(% capital cost)
18,000
NA
14,400
0.80
NA
NA
160,000
NA
84,800
0.53
NA
NA
250,000
NA
75,000
0.30
NA
NA
500,000
NA
105,000
0.21
NA
NA
1,000,000
NA
140,000
0.14
NA
NA
OFFSITE DETENTION PONDS CREATED FROM NATURAL LOW AREAS- Orlando, Florida; APWA
, Res. Foundation
Storage Drainage
Volume Area
(cu. ft.) (acres)
250,000 NA
500,000 NA
1,000,000 NA
2,000,000 NA
Total
Cost Cost/Cu. Ft.
(1988 $) ($/cu. ft.)
40,000 0.16
55,000 0.11
50,000 0.05
80,000 0.04
Cost/Acre
(Sfec.)
NA
NA
NA
NA
Annual
Maint. Cost
(% capital cost)
NA
NA
NA
NA
80040000\123\report
C—25
January 29, 1993
-------
OFFSITE DETENTION PONDS REQUIRING SUBSTANTIAL EXCAVATION- Orlando, Florida; APWA
Res. Foundation
Storage
Volume
(cu. ft.)
500,000
1,000,000
2,000,000
Drainage
Area
(acres)
NA
NA
NA
Total
Cost
(1988$)
505,000
760,000
1,000,000
Cost/Cu. Ft.
($/cu. ft.)
1.01
0.76
0.50
Cost/Acre
fS/ac.)
NA
NA
NA
WET PONDS WITH PUMPED REMOVAL - Chicago, III.; APWA Res. Foundation
Storage Drainage
Volume Area
(cu. ft.) (acres)
26,100,000 13,250
Total
Cost Cost/Cu. Ft. Cost/Acre
(1988 $) ($/cu. ft.) ($/ac.)
5,380,346 0.21 406
WET PONDS- Tri-County, Michigan; SE Wise. Reg. Planning Comm., 1991
Storage Drainage
Volume Area
(cu. ft.) (acres)
283,140 NA
Total
Cost Cost/Cu. Ft. Cost/Acre
(1988 $) ($/cu. ft.) ($/ac.)
81,243 0.29 NA
Annual
Maint. Cost
(% capital cost)
NA
NA
NA
Annual
Maint. Cost
(% capital cost)
NA
Annual
Maint. Cost
(% capital cost)
2.5%
WET PONDS - Southeastern Wisconsin; SE Wise. Reg. Planning Comm., 1991
Storage
Volume
(cu. ft.)
43,560
130,680
217,800
435,600
871,200
Drainage
Area
(acres)
NA
NA
NA
NA
NA
Total
Cost
(1988 $)
32,542
61,460
94,022
146,492
227,900
Cost/Cu. Ft.
ft.)
0.75
0.47
0.43
0.34
0.26
Cost/Acre
($/ac.)
NA
NA
NA
NA
NA
Annual
Maint. Cost
(% capital cost)
NA
NA
NA
NA
NA
80040000\123\report
C—26
January 29, 1993
-------
WET PONDS - Southeastern Wisconsin (estimated from graphs caluculated from unit costs);
SWRPC, 1991
Storage
Drainage
Total
Annual
Volume
Area
Cost
Cost/Cu. Ft.
Cost/Acre
Maint. Cost
(cu. ft.)
(acres)
(1988 $)
($/cu. ft.)
($/ac.)
(% capital cost)
30,000
NA
25,000
0.83
NA
5%
50,000
NA
31,000
0.62
NA
4%
75,000
NA
40,000
0.53
NA
4%
100,000
NA
48,000
0.48
NA
4%
250,000
NA
100,000
0.40
NA
3%
500,000
NA
200,000
0.40
NA
3%
1,000,000
NA
330,000
0.33
NA
3%
WET PONDS- Salt Lake County, Utah; SE Wise. Reg. Planning Comm., 1991
Storage
Volume
(cu. ft.)
NA
Drainage
Area
(acres)
160
Total
Cost
(1988 $)
53,068
Cost/Cu. Ft.
ft/cu- ft-)
NA
Cost/Acre
($/ac.)
NA
WET PONDS- Fresno, California; SE Wise. Reg. Planning Comm., 1991
Annual
Maint. Cost
(% capital cost)
1.5%
Storage
Drainage
Total
Annual
Volume
Area
Cost
Cost/Cu. Ft.
Cost/Acre
Maint. Cost
(cu. ft.)
(acres)
(1988 $)
($/cu. ft.)
(S/ac.)
(% capital cost)
NA
NA
1,231,163
NA
NA
0.5%
NA
NA
1,716,868
NA
NA
0.3%
NA
NA
7,207,230
NA
NA
<0.1%
NA
NA
1,201,538
NA
NA
0.9%
NA: Not Available
80040000\123\report
C—27
January 29, 1993
-------
CHART 5. UNIT CONSTRUCTION COST AND TOTAL ANNUAL COST OF WET AND EXTENDED DETENTION WET PONDS
O
o 01
U
CO
£3
C
c
<
o
H
5
10,000
WET & ED WET PONDS
TOTAL AN]
MUAL COST/CU F1
fSTORAGE
100,000 1,000,000
Storage, cu.ft.
3
O
CO
o
O
c
o
o
c
D
0.01
1000
WET PONDS
COST/CU FT STORAGE
10000
100000 1000000
Storage, cu. fL
10000000 100000000
80040000\123\report
C—28
January 29, 1993
------- |