Bassett Creek Water
Management Commission
Water Quality Management Policy
Executive
Summary
The lakes, rivers, ponds, streams, and
wetlands of the Bassett Creek Watershed are an important community asset. These resources
supply aesthetic and recreational benefits, in addition to providing wildlife habitat and
refuge. The Bassett Creek Water Management Commission recognizes a need to assure adequate
water quality in the water bodies in its jurisdiction, and has taken steps to protect
these resources.
Phosphorus and suspended sediment are recognized as being particularly
detrimental to the health of lakes and streams. As a result, the Commission is requiring
measures to reduce the influx of these pollutants to its water bodies. Furthermore, to
better plan its strategy, the Commission has identified projected uses and corresponding
water quality goals for each of the major water bodies in the watershed.
Wherever possible, the Commission plans to make use of regional
treatment facilities to manage water quality. However, in addition to regional treatment,
sound water management practices must occur on the local level. To this end, the
Commission intends to review plans for construction activities within its jurisdiction to
ensure that water quality goals are met.
This document sets forth the Water Quality Management Policy of the
Commission. Part I of this document explains the rationale and strategy of the Bassett
Creek Water Management Commission in establishing its Water Quality Management Policy.
Part II describes the Commission?s review process and its specific requirements for
construction activities within the watershed.
Part
I: Rationale for the Policy
Introduction
When natural areas are urbanized, stormwater runoff from
new roads, highways, industries and homes carries pollutants at above-natural rates to
adjacent water bodies. Numerous studies have documented the adverse water quality impacts
associated with converting land from its native, undisturbed state to urban land uses.
Outflow from urbanized areas accelerates the natural eutrophication of our lakes, streams
and rivers.
At the same time, an increased population density generally results in an increased
appreciation for the many benefits of urban lakes, rivers, wetlands, and streams. This
results in strong pressure to mitigate the impacts of urbanization, and to reduce the
effects of past water quality degradation.
The Bassett Creek Water Management Commission (Commission) is mandated to manage the
water resources of the watershed in order that the beneficial uses of wetlands, lakes, and
streams remain available to the community. Such uses may include simple aesthetic
appreciation, wildlife observation, swimming, boating, or others.
The Commission recognizes a public need for water quality protection and improvement
within its jurisdiction, and accepts water quality management as one of its highest
priorities. Part I of this document outlines the Commission?s objectives with regard to
water quality in the Bassett Creek Watershed. Part II gives the standards the
Commission has adopted in seeking to meet these objectives. This policy was adopted by the
Basset Creek Water Management Commission at its September 14, 1994 meeting. Revisions
to the policy were adopted at the Commission?s December 18, 1997 meeting.
Objectives and
Strategy
The expected use and corresponding desired water quality
for a particular water body may be quite different from those of another lake, pond or
stream. For example, a large lake in the midst of a residential area may be expected to
provide safe and healthful swimming for local citizens. Water quality in this situation
would need to be excellent. By contrast, the water quality expectations for a small and
relatively neglected pond in a predominantly commercial zone would be lower.
Realizing this distinction between water bodies, the Bassett Creek Water Management
Commission found it useful to classify water bodies according to their expected use and
corresponding required water quality. Table 1 shows the water quality classifications
adopted by the Commission. These classifications rank water bodies by the water quality
required to support either current, or desired future uses.
Table 1
Definition of Management Classifications
According to Desired Uses
| Level I |
Level I water bodies fully
support all water-based recreational activities including swimming, scuba diving and
snorkeling. |
| Level II |
Level II water
bodies are appropriate for all recreational uses except full body contact activities.
Recreational activities for these water bodies include: sailboating, water skiing,
motorboating, canoeing, wind surfing and jet skiing. |
| Level III |
Level III water bodies will
support fishing, aesthetic viewing activities and observing wildlife. |
| Level IV |
Level IV water bodies are water
resources generally intended for runoff management (i.e., stormwater detention) and have
no significant recreational use values. |
It can be seen that Level I water bodies will require
the highest water quality. Levels II, III, and IV water bodies require successively lower
water quality to support their intended use.
Using the system shown in Table 1, classifications for the major water bodies within
the Bassett Creek Watershed were decided upon by the Commissioners. These classifications
were based on public input, and resulted from consultation with the staff and elected
officials of the cities within the watershed.
For example, water quality goals for Medicine lake were set by the Commission in 1974,
after discussions of the effect of the lake?s water quality on its recreational use. The
water quality that existed in Medicine Lake in 1974 was consistent with the desired use.
However, since 1974, the water quality of Medicine Lake has deteriorated and future
restorative measures will be needed to reach the water quality goal. The management
classifications for Medicine Lake and for the rest of the major water bodies in the
Bassett Creek Watershed are shown in Table 2.
Table 2
Management Classifications of
Major Water Bodies in Bassett Creek Watershed
Watershed
Description |
Water
Body |
Management
Classification |
| Main Stem |
Grimes Pond
N. Rice Pond
S. Rice Pond
Birch Pond
Wirth Lake
Westwood Lake
Bassett Creek (Mississippi
River to Medicine Lake) |
Level III
Level III
Level III
Level III
Level I
Level II
Level III |
| North Branch |
Lost Lake
Northwood Lake
Bassett Creek Park Pond |
Level II
Level II
Level III |
Medicine Lake
Branch |
Parker's Lake
Turtle Lake
Crane Lake
Medicine Lake |
Level I
Level II
Level III
Level I |
Sweeney
Branch |
W. Ring Pond
E. Ring Pond
Courtlawn Pond
Twin Lake
Sweeney Lake |
Level III
Level III
Level III
Level I
Level I |
Level I = Recreational (All Activities)
Level II = Recreational (Non-Body Contact Activities)
Level III = Aesthetic Viewing
Level IV = Runoff Management
After classifying the water bodies of the Bassett Creek Watershed, the Commission set
specific water quality goals for each lake or stream, and analysis was made of the steps
that would be required to meet these goals. It became clear that the water quality goals
could not be met without taking measures to assure adequate water quality in the
subwatersheds draining to the water bodies. As a result, watershed management, including
review of land development, forms a major component of the management program for the
lakes and streams of the Bassett Creek Watershed.
The Commission's watershed management and land development policies are directed mainly
at controlling the amount of phosphorus that is carried in the runoff from the watershed.
High phosphorus levels in lakes lead to algal proliferation. An abundance of algae reduces
the clarity of the water, may result in impairment of fish habitat, and can cause scum and
odor problems. Water quality monitoring of Basset Creek waters shows control of phosphorus
levels to be the key to controlling algal growth.
Closely related to the reduction of phosphorus loads to the water bodies is the control
of suspended sediment inflows. Suspended sediment?fine particles of soil, dust and dirt
carried in moving water?results from stormwater runoff from streets and parking lots, and
abounds when erosion occurs. This sediment load clouds streams and lakes, thereby
disturbing aquatic habitats. It also is a major source of phosphorus, which is frequently
bound to the fine particles. As a result, many of the Commission?s standards are aimed at
preventing or slowing the transport of fine soil, dust and dirt particles into the streams
and lakes.
To address its water quality concerns, an overall water quality management plan is
currently being developed by the Commission. The plan will identify where regional basins
can be developed in the watershed to meet the water quality goals adopted by the
Commission. The plan will also estimate the development cost of those regional facilities.
After adoption of the water quality plan and the capital improvement plan by the
Commission, property owners/developers in the watershed of those regional facilities may
be required to contribute to the cost of those regional facilities. Their portion of the
cost will be in proportion to their contribution of nutrients to the total contribution of
nutrients to the regional facility.
The Commission intends to use regional watershed treatment facilities wherever possible
to attain the water quality goals for the watershed. In addition to regional treatment,
however, implementation of Best Management Practices (BMPs) will be required on
construction sites throughout the watershed. Such practices are seen as particularly
important in areas of the watershed where regional detention facilities have not been
established or are not feasible.
To encourage water quality protection and the use of BMPs, the Commission intends to
review plans for construction activities within the Bassett Creek Watershed in accordance
with this policy. Activities within the subwatersheds will be regulated according to the
classification (Level I, II, III, etc.) of the receiving water listed in Table 2.
General level-dependent requirements for stormwater treatment are shown in
Table 3. The treatments listed are intended to reduce phosphorus, suspended sediment,
and other pollutant loads carried by the stormwater runoff.
Table 3
General Requirements for Water Management
According to Management Classification
Management
Classification |
Best
Management Practices |
Runoff Treatment |
Sediment-tation |
Skimming |
Nutrient
Removal |
| Levels I and II (Recreation) |
Required |
Required |
Required |
Required |
| Level III (Aesthetic Viewing) |
Required |
Required |
Required |
May be
Required |
| Level IV (Runoff Management) |
Required |
Not
Required |
Not
Required |
Not
Required |
| Wetlands (Types 2-8) |
Required |
Not
equired |
Not
Required |
Not
Required |
Particular requirements designed to achieve
the Commission?s water quality goals are outlined in Part II of this document. Part II of
this document gives a complete listing of the water quality control standards and design
criteria that have been adopted by the Commission. Part II describes:
- Which projects will require a submittal for review.
- The nature of the review process.
- What exhibits will be required in the submittal.
- What the standards are for the required ?Water Quality Management Plan,? in accord with
the classification of the receiving water body.
- What the standards are for the required Erosion Control Plan.
- How a variance from the standards may be applied for.
Part II: Water Quality Management
Standards
1. Projects for
Which Best Management Practices Must be Considered
a. It is the policy of the Bassett Creek Water Management Commission (Commission) to
require that, prior to commencing construction or reconstruction of a site, all persons,
municipalities or other agencies proposing improvements, developments, or redevelopments
within the Bassett Creek watershed for residential, commercial, industrial, institutional,
or public uses shall submit information regarding the project to the Commission in
conformity with the requirements of this policy. They shall further secure comments from
the Commission regarding the conformance of the project to the policies of the Bassett
Creek Water Management Plan. [Note: an NPDES permit for construction activity is
required from the Minnesota Pollution Control Agency for projects which disturb five or
more acres of area.]
b. A commercial, industrial, institutional or public development is defined
as a project involving a site of more than 0.5 acres of land where there is no
existing commercial, industrial, institutional or public development. A commercial,
industrial, institutional or public expansion/addition is defined as a project
involving a site that was partially developed prior to adoption of the Commission?s Water
Quality Policy (September 14, 1994) and involves grading more than 0.5 acres of land. A commercial,
industrial, institutional or public redevelopment is defined as a project involving a
site of more than 5 acres of land where the commercial, industrial, institutional,
residential or public development currently exists.
c. A residential development is defined as a project involving a site of more
than 2 acres and which contains four or more proposed living units. A residential
redevelopment is defined as a project involving more than 10 acres where there
are four or more existing living units.
d. A road construction or reconstruction project involving a site of more than 5
acres of land for which the site runoff is not currently directed to an onsite or
regional treatment facility. This policy results from the Commission?s goal to eliminate
direct discharges from roadways to a Level I, II, or III water body, including Bassett
Creek.
e. If the Commission has approved a municipal Stormwater Management Plan for a
municipality, or for a subwatershed within a municipality, the requirements of this policy
which are met by the municipal plan shall be deemed satisfied upon showing compliance with
the municipal plan.
2. Review Procedure
Refer to Section B for review procedure.
3.
Required Exhibits for Submittal for Review
A submittal for review shall include two sets of exhibits
for Commission review, one set to be returned to the municipality with Commission
comments, and one set to be retained in the Commission files. The following exhibits shall
be included in a submittal:
a. A set of Project Plans, including at least:
(1) A scale drawing of the site showing property lines and delineation of lands under
ownership of the applicant.
(2) Proposed and existing stormwater facilities location, alignment and elevation.
(3) Existing and proposed site contour elevations related to NGVD, 1929 datum.
(4) Construction plans and specifications of all proposed stormwater management
facilities.
b. A Runoff Water Quality Management Plan and Computations, signed by a
registered professional engineer, and meeting the minimum requirements described in
Paragraph 4 of these standards. Pond sizing and average depth calculations must also be
provided.
c. A final Erosion Control Plan meeting the requirements of Paragraph 5 of these
standards.
d. Completed Application Form and checklist of Best Management Practices.
4. Runoff Water Quality
Management Plans--Minimum Standards
A Runoff Water Quality Management Plan shall include the
following items:
a. Delineation of the subwatersheds contributing runoff from offsite, and proposed and
existing subwatersheds onsite.
b. Delineation of existing onsite wetlands, marshes, and/or floodplain areas.
c. Existing 5-year; and proposed post-development normal, 5-year and 100-year
stormwater elevations for the site.
d. Stormwater runoff volume and rate analyses for existing and proposed conditions for
5-year and 100-year storm events.
e. All hydrologic and hydraulic computations necessary to design the proposed
stormwater quality management facilities.
f. Documentation indicating conformance with an existing municipal Stormwater
Management Plan. If a municipal Plan does not exist, documentation indicating that the
municipality has reviewed the project.
5. Best Management
Practices--Minimum Standards
a. Best Management Practices--General.
A checklist of Best Management Practices such as those shown in Table 4 (see end of
this document) shall be submitted demonstrating that, to the maximum extent practical, the
plan has incorporated the structural and non-structural BMPs, as described in the book Protecting
Water Quality in Urban Areas (Minnesota Pollution Control Agency, 1989). A list of
other BMPs is given in Table 5 to illustrate the range of practices that minimize the
adverse effects of stormwater runoff on receiving waters.
b. Best Management Practices--Expansion/Addition Projects. For commercial,
industrial, institutional or public expansion/addition projects, the Commission
realizes that existing development may limit the type of best management practices that
can be implemented for the entire site. The most desirable best management practice is to
construct a permanent wet detention basin to serve the entire site. At a minimum, a wet
detention basin must be constructed to serve the expansion/addition and, if applicable,
the increased contributing drainage area of the basin. Other appropriate best management
practices will be required for the existing development if wet detention for the increased
contributing drainage area is not practical. The Commission will work with the project
applicant to assist with determining the appropriate temporary and permanent best
management practices to implement for the project.
c. Best Management Practices--Road Projects. Best management practices must be
considered to improve the quality of stormwater runoff from road construction and
reconstruction projects. The most desirable best management practice is the
construction of a permanent wet detention basin, if possible. The Commission realizes that
existing development and right-of-way constraints will limit the type of best management
practices that can be implemented. At a minimum, temporary measures will be required to
address erosion and sediment control during construction. The Commission will work with
the project applicant to assist with determining the appropriate temporary and permanent
best management practices to implement for the project. The project applicant must submit
a description of the evaluation process used to identify feasible best management
practices to be implemented on the project.
Examples of applicable construction (temporary) best
management practices include, but are not limited to:
- Silt fence/hay bales
- Temporary diversions
- Temporary stream crossings
- Catch basin inlet protection
Examples of permanent best management practices include, but are not limited to:
- Detention basins (wet and dry); these can be formed along ditches through the use of
permeable check dams or weirs
- Infiltration
- Vegetated swales
- Slope erosion protection
- Streambank protection
- Filter strips
- Infiltration trenches
Grit chambers or sump manholes are another possible best management practice for
capturing sediment. They are less desirable best management practices because of the need
for frequent inspection and cleaning at least twice per year to be effective. If either is
proposed to be used, the project applicant will be required to submit a maintenance
schedule.
6.
General Ponding Requirements
In general, it is the Commission's policy to manage its
water resources using the regional detention basin concept. However, where regional basins
have not been constructed or cannot be developed, sound water quality management requires
the use of onsite detention basins or other features to meet water quality goals
established for Bassett Creek watershed receiving water bodies.
a. Natural or excavated low areas will be used for the detention basins. Generally
accepted reservoir routing procedures using critical duration runoff events shall be used
for design of these areas and outlets.
b. The size and design of the onsite detention basin will depend on the receiving water
body's management category (see Table 2) and flow conveyance capacity, the quantity
of impervious surface within the development, and the degree to which onsite infiltration
of runoff is encouraged. Onsite detention basins shall be designed based on the following:
(1) Water Quality Goals
Detention basin shall achieve pollutant removal efficiencies equal to or greater than
those obtained by implementing the criteria set forth by the Nationwide Urban Runoff
Program (NURP) and Protecting Water Quality in Urban Areas (MPCA, 1989) with
specific consideration to the receiving body water quality goals. Design of onsite
detention basins will depend, to some extent, on the Commission's water quality goals for
the receiving water. For example, if the receiving water body has a Level I water quality
goal, the detention basin discharging to that lake or stream must achieve high pollutant
removal efficiencies. A Level IV goal, by contrast, would not demand that efficiencies be
as high.
(2) Water Quantity Goals0--Flow Conveyance Capacity
Onsite detention basins shall avoid or minimize increases in predevelopment runoff
rates to the greatest extent practical. The capacity of the receiving body to convey
and/or store the runoff shall also be considered so as to not adversely affect water
levels off the site.
(3) Alternatives to Onsite Ponds
Alternative water quality management features may be used where onsite ponds are not
feasible. Alternative features must be designed to provide water quality benefits that
equal or exceed design criteria outlined in existing Commission policies.
7.
Water Quality Pond Design Criteria
Following is the detention basin design criteria that must
be met for each water quality management classification (Levels I, II, III, etc.)
based on the receiving water body. See Table 2 to determine the water quality management
classification of the receiving water body.
a. Level I Water Bodies and Streams
(1) The permanent pool ("dead storage") volume below the principal spillway
(normal outlet) shall be greater than or equal to the runoff volume from a 2.5-inch,
24-hour storm over the project site, assuming full development. Under special conditions,
such as expansions to existing water quality ponds, the entire contributing drainage area
will need to be considered in computing the dead storage volume, assuming full development
of the drainage area.
(2) The permanent pool average depth (basin volume/basin surface area) shall be > 4 feet,
with a maximum depth of < 10 feet. For small ponds (less than
3 acre-feet in volume) average depth shall be > 3 feet, with a
maximum depth of < 10 feet. An "effective average depth"
(basin "effective volume"/basin "effective surface area") may be
calculated for ponds that include basin shelves. The "effective volume" and
"effective surface area" are computed by extending the basin sideslopes below
the basin shelf, vertically, to the water surface.
(3) An emergency overflow (emergency outlet) must be in place and adequate to
accommodate the 100-year frequency critical duration rainfall event.
(4) Basin side slopes above the normal water level shall be no steeper than 3:1 when
possible, and preferably flatter. A basin shelf with a minimum width of 10 feet and 1
foot deep below the normal water level is recommended to enhance wildlife habitat, reduce
potential safety hazards, and improve access for long-term maintenance.
(5) To prevent short-circuiting, the distance between the major inlets and normal
outlet shall be maximized.
(6) The flood pool ("live storage") volume above the principal spillway shall
be such that the peak discharge rate from the 5-year frequency, critical duration storm
does not exceed the peak discharge for a similar storm under predevelopment conditions.
(7) Extended detention of runoff from the more frequent (1-year to 5-year) storms shall
be achieved through a principal spillway design which shall include a perforated vertical
riser, small orifice outlets, or a compound weir.
(8) The design must include effective energy dissipation devices that reduce outlet
velocities to 4 fps or less. These outlets shall consist of stilling basins or other
such devices that prevent erosion at all stormwater outfalls into the detention basin, and
at the basin outlet. Storm sewer outfalls must extend to the detention basin or other
receiving water body and must discharge at or below its normal water elevation.
(9) Trash and floatable debris skimming devices shall be placed on the outlet of
all onsite detention basins to provide treatment up to the critical duration 5-year storm
event. Submerged inlets, permanent baffled weirs or similar devices may be employed.
Timber baffled weirs are discouraged. Velocities through the devices shall be less than
0.5 fps. The top of submerged inlets shall be at least one foot below the water
surface.
(10) During construction of the basin, care shall be taken to prevent the discharge of
waterborne sediments to downstream water bodies.
b. Level II Water Bodies and Streams
(1) The permanent pool (dead storage) volume below the principal spillway (normal
outlet) shall be greater than or equal to the runoff volume from a 2.0-inch, 24-hour storm
over the project site, assuming full development. Under special conditions, such as
expansions to existing water quality ponds, the entire contributing drainage area will
need to be considered in computing the dead storage volume, assuming full development of
the area.
(2) All other requirements as listed above for Level I water bodies.
c. Level III Water Bodies and Streams
(1) The permanent pool ("dead storage") volume below the principal spillway
(normal outlet) shall be greater than or equal to the runoff volume from a 1.5-inch,
24-hour storm over the project site, assuming full development. Under special conditions,
such as expansions to existing water quality ponds, the entire contributing drainage area
will need to be considered in computing the dead storage volume, assuming full development
of the area.
(2) All other requirements as listed above for Level I water bodies.
d. Level IV Water Bodies and Streams
(1) Energy dissipation devices as described for Level I water bodies, and any and
all other practical measures needed to maintain the function and character of the
Level IV water body.
e. Wetlands (Type 2-8)
(1) Energy dissipation devices as described for Level I water bodies, and any and
all other practical measures needed to maintain the function and character of the wetland.
8.
Erosion Control Plans--Minimum Standards
Refer to Section F for criteria.
9. Variances from the Water
Quality Management Policy
a. Applications for variances shall be filed with the City where the property being
developed, redeveloped, or retrofitted is located and shall state the exceptional
conditions of the property and the peculiar and practical difficulties claimed as a basis
for a variance. The applicant shall state on the application the reasons for requesting
the variances, in accordance with all the requirements set forth in Section (c) below.
b. All applications for variances shall be referred by the City to the Bassett Creek
Water Management Commission's Engineer, and shall be reviewed by the Commission. In
reviewing the application, the Commission shall take into consideration the criteria,
standards, and goals for maintaining and improving the quality of the watershed's public
waters.
To address the applicant's hardship or special situation, the Commission may grant the
variance, contingent upon conditions that the Commission may set forth. Alternatively, the
Commission may deny the request and set forth reasons for the denial.
c. In granting variances, the Commission shall make a finding showing that all of the
following conditions exist:
(1) There are special circumstances or conditions affecting the property such that the
strict application of the provisions of these standards and criteria would deprive the
applicant of the reasonable use of its land.
(2) The variance is necessary for the preservation and enjoyment of a substantial
property right of the applicant.
(3) The granting of the variance will not be detrimental to the public welfare or
injurious to the other property in the territory in which the property is situated.
(4) In applications relating to a use in the floodplain or within the management
envelope set forth in the management plan, the variance shall not allow a lower degree of
flood protection than the flood protection elevation stated in the management standards.
(5) The granting of the variance will not be contrary to the intent of taking all
reasonable and practical steps to improve water quality within the watershed.
10. Definitions
a. Road construction or reconstruction projects include any project which
results in the complete removal of the road surface, exposing the base, and/or removal of
the vegetated surface within the road right-of-way. Examples include road widening
projects, ditch work, road replacement and utility installation. Road overlay projects and
road resurfacing projects which do not disturb the road base will not be covered by the
requirements of this policy.
b. Commercial, industrial, institutional or public development projects
typically result in larger areas of impervious surface, typically in the range of 60 to
80 percent imperviousness. Examples of these developments include shopping malls,
stores, schools, hospitals, and warehouses.
c. Residential development projects typically result in smaller areas of
impervious surface, typically in the range of 25 to 60 percent imperviousness. Examples of
these projects include single family home construction, townhome construction and
apartment building construction.
d. Commercial, industrial, institutional or public expansion/addition projects
are additions to existing projects for which approval of the existing project was obtained
prior to adoption of this water quality policy. Examples of such projects include parking
lot expansions/additions and building expansions/additions.
e. Best Management Practices are the structural, non-structural, and
institutional controls used to improve the quality of stormwater runoff. Tables 4 and 5 at
the end of this section provide examples of common best management practices. Additional
best management practices may be found in Protecting Water Quality in Urban Areas
(MPCA, 1989).
f. Onsite or regional treatment facility is a stormwater treatment basin
designed to treat the stormwater runoff generated from either the project site (onsite) or
an area larger than the project site (regional).
g. Complex projects include projects that are 40 acres or more,
controversial, involve more than one property owner, require detailed hydrologic or
hydraulic modeling, require vast changes to infrastructure (such as stormwater systems),
include many wetland impacts, require extensive environmental review, or involve many
different land uses within the same development project.
h. Stormwater (management) facilities include storm sewer pipes, ditches, ponds,
infiltration basins, etc.
i. Critical duration runoff: Generally accepted reservoir routing procedures
using critical duration runoff events refers to the hydrologic methods, usually computer
models, used to determine flowrates and flood levels resulting from stormwater runoff
events. The event which results in the highest flood level or flowrate is the critical
duration event. Examples of such methods include TR-20, Hydrocad, SWMM, HEC-1 and other
approved watershed models.
Table 4
Checklist of Common
Best Management Practices (BMPs)
For Development or Re-Development
| Description
of BMP |
Was BMP
Used in Project? |
Location
Used or Basis for Nonusage: |
| Discharge Elimination BMPs |
| 1. Reduce area of impervious
surface (pavement, roofs, etc.) |
|
|
| 2. French drains and subsurface
drains |
|
|
| 3. Infiltration trench and dry
well |
|
|
| 4. Exfiltration trench |
|
|
| 5. Porous pavement |
|
|
| 6. Retention (infiltration) basin |
|
|
| Stormwater BMPs |
| 7. Detention Basin with outlet
protection |
|
|
| 8. Extended detention basin |
|
|
| 9. Wetland treatment area |
|
|
| 10. Parking lot/rooftop runoff
storage with outlet protection |
|
|
| 11. Grit chambers/manholes |
|
|
| 12. Diversion channel |
|
|
| Floatable/Oil Removal BMPs |
| 13. Floatable skimmer |
|
|
| 14. Parking lot oil/grease
separators |
|
|
| Sediment Control BMPs |
| 15. Riprap or other storm drain
outlet protection |
|
|
| 16. Storm drain inlet protection |
|
|
| 17. Slope stabilization and
erosion control measures |
|
|
| 18. Vegetated swale |
|
|
| Nonstructural BMPs |
| 19. Street sweeping |
|
|
| 20. Fertilizer management |
|
|
| 21. Other (describe): |
|
|
Table 5
Suggested Best Management Practices
Institutional Source Controls
- No Littering Ordinance
- Pet Feces Removal Ordinance
- Chemical Use/Storage Ordinance
- Recycling Programs
- Public Education Programs
- Vacant Lot Cleanup Ordinance
- Spill Prevention Ordinance
Nonstructural Source Controls
- Program to Prevent Illicit Discharges
- Street Sweeping
- Cleaning of Storm Drains
Minor Structural Source Controls
- Diversion Channels
- Grass Swales
- Natural Channels to Reduce Erosion
- Vegetative Controls on Exposed Soils
- Storm Sewer Outlet Protection
- Slope Stabilization and Erosion Control Measures
- Riprap Protection
Minor Structural Discharge Elimination Methods
- Development and Maintenance of Recharge Areas
- Development and Maintenance of Porous Pavement
- French Drains and Infiltration Trench
Moderate Structural Controls for Floatables/Oils Removal
- Development and Maintenance of Parking Lot Oil/Grease
Separators
- Development and Maintenance of Parking Lot and Rooftop
Runoff Storage with Outlet Protection
Major Structural Controls for Floatables/Oils Removal
- Detention Basin with Outlet Skimmer
- Wetlands Treatment Area
Major Structural Controls for Floatables, Metals,
Microorganisms, and Nutrient Removal
- Lime Precipitation, Filters, and Chlorination/Dechlorination
to Detention Basins
- Lime Precipitation, Chlorination/Dechlorination to Wetlands
|
