This document was prepared to assist developers and consultants to design and manage projects in accordance with the policies of the Bassett Creek Water Management Plan. Copies of the Plan, as adopted by the Bassett Creek Water Management Commission, may be obtained from Barr Engineering Co. The cost of the Bassett Creek Water Management Plan is $25.

This document includes the following:

1. Requirements for Improvements and Development Proposals

This section includes general submittal requirements as set forth in the Bassett Creek Water Management Plan.

2. Appendix: Water Quality Management Policy

The Appendix includes the Commission's Water Quality Management Policy adopted September 14, 1994. The policy outlines specific requirements for development and redevelopment proposals. Water quality requirements are primarily based on the area of the proposed site and the receiving water body of site runoff.

The types of projects that must be submitted to the Commission for review are described in Part A.

In order to facilitate the management of the water resources of the watershed, cooperation between the Bassett Creek Water Management Commission, member municipalities and concerned citizens is important. Consistent with policies of the Commission and the Joint Powers Agreement, the Commission desires to be informed of improvements or land development proposals which may affect the water and related resources of the watershed. The Commission will provide information and assistance in the preliminary planning stages of these improvements or land development proposals; however, because of the increasing number of developments requiring review, a review procedure is necessary. The Commission will limit their formal review of improvements and development proposals until the City staff has completed their review and established that the improvement or development proposals conform to their local municipal ordinances and regulations. The Commission will then review the proposals and submit their comments and recommendations to the City and other appropriate governmental agencies prior to the final approval or disapproval of the City or other governmental agency.

All persons, municipalities or other agencies proposing improvements or developments within the Bassett Creek watershed shall submit sufficient information to determine the effect that their proposal may have on the water resources of the watershed within the following guidelines:

1. Floodplains

Any proposal which would consist of a major alteration of existing structures, erection of new structures, filling, floodway encroachment, activities considered incompatible with acceptable floodplain uses or be subject to damage by the 100-year flood, and is located below the management envelope included in the Bassett Creek Water Management Plan must be submitted for Commission review. This section shall apply to structures such as bridges, footbridges, culverts, and pipe crossings of any nature, including sanitary sewer, water supply, and electrical and telephone lines.

2. Artificial Storage Sites

Any proposal within the limits of the proposed artificial storage sites established by the Bassett Creek Water Management Plan that may be in conflict with the minimum requirements as outlined in the Plan shall be submitted for Commission review.

3. Lakes and Wetlands

Proposals that may affect the water surface elevation, outlet storage capability or shoreline, or be incompatible with existing or proposed land use around the lakes and wetlands in the Bassett Creek watershed shall be submitted for Commission review.

4. Water Resources

Proposals that would alter remaining protected water resources in the watershed, involve the discharge of industrial or other waste to any watercourse or storm sewer, require extensive land alteration, are directly tributary to the watercourses of the watershed, or may otherwise affect the existing water quality shall be submitted for Commission review. In addition, the Commission shall be informed of the proposed application of chemicals or other treatments to lakes and ponds in the watershed.

5. Diversion of Surface Water Runoff

Proposals to provide intra- or inter-watershed diversion which may affect flood levels, lakes levels, and minimum streamflows in the watershed shall be submitted for Commission review.

6. Land Use Changes

Proposed changes in land use, zoning, and municipal drainage plans which may require the modification of the Water Management Plan shall be submitted for Commission review.

7. Appropriations

Ground or surface water appropriations which may temporarily or permanently alter the existing ground and surface water levels in the watershed shall be submitted for Commission review.

8. Utility Crossings

The construction of utilities through or paralleling the creek which require disturbance of the bed or banks of the creek or the diversion of the creek shall be submitted for Commission review.

9. Permit Applications

One copy of all permit applications made to the Minnesota Department of Natural Resources for work in public waters including supporting documentation shall be submitted for Commission review.

10. Water Quality Management Policy

The Commission's Water Quality Management Policy outlines criteria for the design of water quality enhancement features. The policy is intended to insure that water quality objectives are achieved throughout the watershed. A project must be designed in accordance with the water quality policy, when the proposed site meets one of the following development or redevelopment criteria:

a. A commercial, industrial, institutional or public development project involving a site of more than 0.5 acres of land where there is not existing commercial, industrial, institutional or public development.

b. A commercial, industrial, institutional or public redevelopment 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 project involving a site of more than 2 acres and which contains four or more proposed living units.

d. A residential redevelopment project involving more than 10 acres where there are four or more existing living units.

11. Construction Erosion Control

When construction is proposed that will result in more than 200 cubic yards of cut or fill or more than 10,000 square feet of grading, an erosion control plan must be submitted for Commission review. Specific requirements for erosion control plans are included in this report.

The following procedures have been established for review of development proposals by the Bassett Creek Water Management Commission:

1. The Commission will review the developerNs submittal only after the applicant demonstrates that the project has received preliminary approval from the municipality indicating compliance with existing municipal plans.

2. The Commission meetings are held the third Thursday of each month. In order for a proposed project to be included on the agenda, plans should be submitted to the Commission staff at least two weeks prior to the meeting date. Complex projects may require additional review time.

3. Upon receipt of a submittal, the Commission staff will review the submittal and prepare recommendations to the Commission. A memorandum describing each project and the staff recommendations will be sent to the Commissioners and applicant approximately one week before each meeting.

4. The Commission will review and comment upon the submittal at its regularly scheduled meeting. The Commission will approve, conditionally approve, or reject the submittal. A letter with its comments, including a list of deficiencies or required modifications, will be sent to the municipality and to the permit applicant.

5. The applicant shall submit an application form and two sets of plans and specifications for Commission review, one set to be returned to the municipality with Commission comments and one to be retained in the Commission files. The application form must be signed by City staff.

6. Refer to Water Quality Management Policy for required exhibits, if applicable. The Water Quality Management Policy requires preparation and submittal of project plans and a runoff water quality management plan.

The floodplain of a stream can be defined as that area adjacent to a stream which is inundated during times of flood. More specifically, the Minnesota Floodplain Management Act of 1969 defines the floodplain as that area adjoining a watercourse which is subject to inundation by a flood of 100-year frequency. Under the provisions of this act, local governmental units are required to adopt floodplain management ordinances which will include "the delineation of floodplains and floodways, the preservation of the capacity of the floodplain to carry and discharge regional floods, minimization of flood hazards, and the regulation of the use of land in the floodplain." Under the provisions of the required ordinances, no major alteration to existing structures, no new fill and no floodplain use which would unreasonably constrict flood flows will be allowed in the floodplain unless further provisions are made to fully compensate any detrimental effects.

The floodplain in the Water Management Plan has been estimated assuming existing channel conditions and runoff resulting from a 100-year storm occurring over the ultimately urbanized watershed. It represents that area which is subject to floodplain regulations until municipalities have completed storage and channel improvements which are a part of this or subsequent phases of the Water Management Plan. At the present time, all of the municipalities in the Bassett Creek watershed have adopted floodplain management ordinances and are restricting development of floodplain areas.

The following policies regarding floodplain regulation within the Bassett Creek watershed have been adopted:

1. The floodplain of Bassett Creek is defined as that area lying below the 100-year flood elevations as shown in the Water Management Plan of the Commission, or as subsequently revised due to channel improvement, storage site development, or requirements established by appropriate state or federal governmental agencies.

2. No land use of a type which would be damaged by flood waters is permitted within the floodplain.

3. Allowable types of land use which are consistent with the floodplain, such as recreation areas, parking lots, excavations and storage areas, agriculture, and other open space uses, would be allowed only to the extent that they would not increase flooding. Permanent storage piles, fences, and other obstructions which would collect debris or provide restriction to flood flows are not allowed.

4. Filling will generally not be allowed within that floodplain established in the Water Management Plan. If any municipality desires to fill within the established floodplain, such filling will require the approval of the Commission and require provisions for compensating storage and/or channel improvement so that the flood level shall not be increased at any point along the channel due to the fill.

5. Expansion of existing non-conforming land uses within the floodplain will be prohibited unless they are fully floodproofed in accordance with existing codes and regulations.

1. Water Quality Management

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. The Water Quality Management Policy was adopted to protect, preserve, and manage the water resources in the Bassett Creek watershed. The policy is discussed in Part A and a copy of the policy is provided in the appendix.

2. Control of Streambank Erosion and Streambed Degradation

Streambank erosion and streambed degradation control measures must:

a. Be employed whenever the net sediment transport for a reach of stream is greater than zero or whenever the streamNs natural tendency to form meanders directly threatens damage to structures, utilities or natural amenities in public areas.

b. Include effective energy dissipation devices or stilling basins to prevent streambank or channel erosion at all stormwater outfalls. Specifically:

i. Outfalls with outlet velocities of less than 4 fps that project flows downstream into the channel in a direction of 30° or less from the normal flow direction generally shall not require energy dissipators or stilling basins, but they may need some riprap protection.

ii. Energy dissipators shall be sized to provide an average outlet velocity of no more than 6 fps. If riprap is also used, the average outlet velocity may be increased to 8 fps.

iii. Riprap stilling basins shall not be used where outlet velocities exceed 8 fps.

c. Specify riprap consisting of natural angular stone suitably graded by weight for the anticipated velocities.

d. Provide riprap to an adequate depth below the channel grade and to a height above the outfall or channel bottom so as to ensure that the riprap will not be undermined by scour or rendered ineffective by displacement.

e. Specify that riprap be placed over a suitably graded filter material or filter fabric to ensure that soil particles do not migrate through the riprap and reduce its stability.

f. Require that streambank stabilization and streambed degradation control structures be submitted for review by the Commission. The review will consider the need for the work, the adequacy of design, unique or special site conditions, energy dissipation, the potential for adverse effects, contributing factors, preservation of natural processes, and aesthetics.

3. Grit Chambers

Grit chambers for presettlement of stormwater must:

a. Be designed and sized to provide theoretical settlement of a 0.3-mm grit particle in still water at 10°C (based on StokeNs Law).

b. Be designed to provide sufficient storage volume for the settled particles consistent with the maintenance schedule.

c. Include a device to diffuse inflow and provide a relatively uniform distribution of flow over the cross section of the chamber.

d. Provide convenient access for equipment and maintenance personnel to the chamber site and into the chamber itself.

e. Be inspected at least three times a year (spring, summer and fall) to determine the volume of stored grit, and be cleaned immediately whenever significant grit has accumulated or there is a likelihood that the chamber will be full of grit before the next scheduled inspection.

4. Regional Detention Basins

Regional detention basins must:

a. Conform to municipalities stormwater runoff criteria.

b. Have water quality features designed based on Level I management classification as set forth in the water quality management policy.

5. Sediment Collection and Nutrient Entrapment

Wetlands used for sediment collection and nutrient entrapment must conform to the criteria for on-site or regional detention basins (whichever are appropriate). In addition, these wetlands and detention basins must:

a. Detain stormwater runoff in the first 1 1/2 feet of stormwater storage depth for an average period of no less than 48 hours.

b. Provide an outlet structure capable of draining the wetland or basin substantially dry to permit harvesting of wetland vegetation and removal of sediment.

c. Be harvested every fall (usually before October 15) by cutting the vegetation and removing the cuttings to an approved disposal site.

Sediment, in terms of volume, ranks above domestic sewage, industrial wastewaters and chemicals as a major contributor to water pollution. In addition to filling stream channels, ponds and lakes, sediment reduces the oxygen content of water and it carries adsorbed phosphorus into streams and lakes where the phosphorus often stimulates algal blooms.

As development of the Bassett Creek watershed continues, sediment concentration in runoff will increase due to construction activity, unless effective sediment control measures are implemented. Increased sediment concentrations are also associated with runoff from streets, parking lots and other impervious surfaces associated with development.

In order to protect the water resources of the Bassett Creek watershed from increased sediment and associated water quality problems, the Commission has established the following policies to encourage land use planning and development that minimizes sediment yield:

1. The use of on-site settling ponds and/or filter fabric (silt fence) to control the sediment in runoff from construction sites, land clearing or grading operations, is required on all projects as set forth in this document.

2. The sedimentation ponds will be cleaned on a regular interval determined by calculating the sediment yield expected from the tributary watershed and comparing it to the capacity of the pond.

3. Preservation and improvement of marsh areas for sediment removal by natural filtration is recommended as long as the natural intrinsic value of the wetland is not adversely affected.

4. The design of storm sewer, stream channel improvements and channel crossings must consider temporary erosion control and sediment reduction measures to be implemented during construction and permanent measures to eliminate erosion and reduce sediment production during operations.

1. During construction where grading involves more than 200 cubic yards of cut or fill, or disturbs more than 10,000 square feet, an Erosion Control Plan shall meet the standards given in the Erosion and Sediment Control Manual (Hennepin County Conservation District, 1989) and Protecting Water Quality in Urban Areas (MPCA, 1989).

2. Erosion control plans submitted for review shall show proposed methods of retaining waterborne sediments on-site during the period of construction, and shall specify methods and schedules to determine how the site will be restored, covered, or revegetated after construction.

3. In addition, the project proposer shall:

a. Provide specific measures to control erosion based on the grade and length of the slopes on the site, as follows:

(1) Silt fences shall be placed along the toe of the slopes that have a grade of less than 3 percent and are less than 400 feet long from top to toe. The silt fences shall be supported by sturdy metal or wooden posts at intervals of 4 feet or less.

(2) Flow lengths up-slope from each silt fence shall not exceed 400 feet for slopes that have a grade of less than 3 percent.

(3) Silt fences shall be placed along the toe of the slopes that have a grade of 3 to 10 percent and are less than 200 feet long from top to toe. These fences shall be supported by sturdy metal or wooden posts at intervals of 4 feet or less.

(4) Flow lengths up-slope from each silt fence shall not exceed 200 feet for slopes that have a grade of 3 to 10 percent.

(5) Diversion channels or dikes and pipes shall be provided to intercept all drainage at the top of slopes that have a grade of more than 10 percent and are less than 100 feet long from top to toe. Silt fence shall be placed along the toe of said slopes, and shall be supported by sturdy metal or wooden posts at intervals of 4 feet or less.

(6) Diversion channels or dikes and pipes shall be provided to intercept all drainage at the top of slopes that have grades of more than 10 percent. Also, diversion channels or diked terraces and pipes shall be provided across said slopes if needed to ensure that the maximum flow length does not exceed 100 feet. Silt fence shall be placed along the toe of said slopes, and shall be supported by sturdy metal or wooden posts at intervals of 4 feet or less.

b. Require that silt fences or hay bales, staked with at least two sturdy metal or wooden posts per bail, be installed around each catch basin inlet on the site and that this barrier remain in place until pavement surfaces have been installed.

c. Ensure that flows from diversion channels or pipes are routed to sedimentation basins or appropriate energy dissipators in order to prevent transport of sediment to outflow conveyors and to prevent erosion and sedimentation when runoff flows into the conveyors.

d. Provide that site-access roads be graded or otherwise protected with silt fences, diversion channels or dikes and pipes to prevent sediment from leaving the site via the access roads. Each site-access road shall have coarse aggregate filter berms with a minimum height of 2 feet above the adjacent roadway and with maximum side slopes of 4:1.

e. Require that soils tracked from the site by motor vehicles be cleaned daily (or more frequently, as necessary) from paved roadway surfaces throughout the duration of construction.

f. Assure that silt fences and diversion channels or dikes and pipes be deployed and maintained for the duration of site construction. If construction operations interfere with these control measures, the silt fences, diversion channels or dikes and pipes may be removed or altered as needed but shall be restored to serve their intended function at the end of each day.

g. Specify that disturbed areas be revegetated or mulched permanently or temporarily if it can be reasonably anticipated that significant additional grading will not occur within 30 calendar days. A schedule of significant grading work will be required as part of the erosion and sedimentation control plan.

h. Require that temporary or permanent mulch be disc-anchored and applied at a uniform rate of not less than 2 tons per acre.

i. Provide a temporary vegetative cover consisting of a suitable, fast-growing, dense grass-seed mix spread at 1.5 times the usual rate per acre. If temporary cover is to remain in place beyond the present growing season, two-thirds of the seed mix shall be composed of perennial grasses.

j. Provide a 4-foot wide sodded area along the curb line of all streets adjacent to the site and along all property boundaries where runoff could leave the site.

k. Specify a permanent vegetation cover consisting of sod, a suitable grass-seed mixture, or a combination thereof. Seeded areas shall be either mulched or covered by fibrous blankets to protect seeds and limit erosion.

l. Provide temporary on-site sedimentation basins whenever other erosion and sedimentation control practices are inadequate. On-site detention basins shall be designed to 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).

The following rules and regulations regarding water resource management are enforced by the Department of Natural Resources.

1. Permit Application

Any project constructed below the ordinary high water mark (OHW) which alters the course, current, or cross-section of state protected waters or wetlands is subject to the regulatory jurisdiction of the Minnesota Department of Natural Resources (DNR). This includes filling, excavation, construction of structures, water level control and drainage projects.

For lakes and wetlands, the OHW is defined as the highest water level that has been maintained for a sufficient period of time to leave evidence upon the landscape. The OHW is commonly that point where the natural vegetation changes from being predominantly aquatic in nature, to predominantly terrestrial. For watercourses, the OHW is the elevation of the top of the bank of the channel.

Any work requiring a permit and commencing without a permit is a violation of state law and constitutes a misdemeanor punishable by fines of up to $700 and/or 90 days in jail. If there is a question about whether or not a particular lake, marsh, or stream is a protected water or wetland, copies of the DNR protected waters map are available for public inspection at the DNR Metro Region, Soil and Water Conservation District offices, and County Auditor offices.

To ensure equitable allocation and the conservation of surface and groundwater resources, appropriation permits are required for any withdrawal of water exceeding 10,000 gallons per day or a total of 1 million gallons.

2. Land Use