(A) A property owner or contractor who removes substantial vegetative growth for any reason including landscaping, excavating for a building foundation or other purpose, or adds soil or other fill on property within the city shall take the necessary precautions to prevent soil erosion, damage to adjacent property and control runoff to surface water. Property owners and contractors shall adhere to erosion and sediment control standards and specifications contained in the Minnesota pollution control agency (MPCA) publication "Protecting Water Quality In Urban Areas", as may be amended, the city of Farmington comprehensive plan and official controls, and any applicable water management plan of the city or other governmental units. Projects disturbing more than one acre shall follow the most current general permit to discharge stormwater associated with construction activity under the national pollutant discharge elimination system/state disposal system permit program (the permit) issued by the MPCA, as amended. The city may impose additional erosion and sediment control requirements if, in the opinion of the city engineer or designee, said measures are necessary to protect adjacent properties and manage surface water runoff.
1. No land shall be developed and no use shall be permitted that result in water runoff causing flooding, erosion, or deposit of sediment on adjacent properties. Such runoff shall be properly channeled into a storm drain, watercourse, ponding area, or other public facilities subject to the review and approval of the city engineer or designee. Appropriate erosion and sediment control measures shall be taken throughout the construction process. They include, but are not necessarily limited to, the use of erosion control fences, wood fiber blankets, rock construction entrances, seeding and/or mulch. If silt fence is required for erosion control, the builder is responsible for properly installing erosion control immediately after backfill of a foundation. If the required erosion control is not installed within twenty four (24) hours after backfill of a foundation, the builder will be issued a stop work order until erosion control measures meet city requirements. The builder is responsible to maintain the silt fence during the construction process. Other techniques or combinations of the above may be used. The erosion and sediment control measures shall be maintained and repaired throughout construction and until such time as the property has been either sodded or a seeded vegetative cover has taken hold. The city engineer or designee may require additional erosion and/or sediment control at any time to ensure that erosion does not occur. All temporary erosion and sediment control devices including silt fence, gravel, hay bales or other measures shall be removed from the construction site and properly disposed of or recycled. This removal and disposal must occur within thirty (30) days of the establishment of permanent vegetative cover on the disturbed area. Final stabilization of the site must be completed in accordance with the permit.
2. Proposed erosion and sediment control measures may be approved by the city engineer, or designee, as part of site plan, landscaping or grading plan reviews in the context of site topography and drainage. Erosion and sediment control may be specified by the city engineer, or designee, as part of a site survey for individual building permits or other city approvals. Plans and permits must be kept up to date by the owner or contractor. Erosion and sediment control measures may also be specified by the city engineer, or designee, as needed and deemed appropriate during the construction and postconstruction periods for permitted or unpermitted activities separate from the above.
3. Exposed soil, including stock piles shall be stabilized immediately where activity has permanently or temporarily ceased on any portion of this site and will not resume for a period of time exceeding fourteen (14) days. After connecting drainage ditches or swales that drain water from the site, the last two hundred (200) linear feet must be stabilized within twenty four (24) hours after connecting to surface water. All seeded areas shall be mulched and disk anchored, or covered with a Minnesota department of transportation approved fiber blanket, as necessary for erosion protection and seed retention.
4. Mud, dirt, or other sediment carried onto city streets, trails or adjacent properties from the building site shall be removed by the property owner or contractor prior to the close of each workday. If cleanup of the mud, dirt or other sediment is not carried out as required above, the city engineer, or designee, may direct city crews and/or contract a third party to complete the cleanup and bill the property owner or contractor for all associated costs, or deduct these amounts from any required bond or security. Unpaid charges will be certified by the city for collection with taxes and no city license, permit, or other approval shall be issued for the property while any charge is outstanding.
5. Temporary rock entrances are required on every construction site and are required after backfilling of foundation. If the rock entrance is not installed immediately after backfilling, a stop work order will be issued until the rock driveway is installed. Rock driveways will also be required during the winter months after backfilling the foundation.
6. All on site stormwater conveyance channels shall be designed and constructed to withstand the expected velocity of flow from a 10-year frequency storm without erosion.
7. If dewatering is to take place, adequate treatment must be provided so that nuisance conditions will not result from the discharge.
8. If temporary sediment basins are to be utilized, design and construction must follow according to the permit.
9. Management of solid and hazardous wastes.
10. A trained person shall inspect the entire site at least once every seven (7) days during active construction and within twenty four (24) hours after a rainfall event greater than 0.5 inch in twenty four (24) hours. A record of rainfall amounts must be documented.
11. Final stabilization:
(a) Interior lots shall be sodded from the roadside edge or the unpaved right of way to the back corners of the furthermost building.
(b) Corner lots with two (2) sides of the lot adjacent to the street; in the front yard, sod shall be installed from the roadside edge or the unpaved right of way in the front of the building to the back corners of the furthermost building. Sod shall also be installed on the street side yard within the boulevard commencing at the rear corner of the building to the rear lot line.
(c) All areas that required silt fences during construction and along any portions of the lot that adjoin drainage easements shall be sodded. Any remaining disturbed areas not mentioned above may be seeded. Silt fences must be maintained throughout the construction period until new vegetation is established.
(d) Turf slopes in excess of three to one (3:1) are prohibited.
12. Failure to comply with any of the above requirements will result in the issuance of a stop work order halting construction until the project area is brought into compliance. Failure to remedy the situation within a reasonable time determined by the city engineer or designee will result in the issuance of a citation for violation of this section. Failure to have erosion and sediment control measures in place may also result in denial of a certificate of occupancy for the structure under construction.
13. The city shall collect a surety for the as built certificate of survey and turf establishment before any building permit is issued. The surety is returned to the person who posted the security when the as built certificate of survey, sod and seed requirements have been approved. If these requirements are not met, the surety will be used to either complete the grading of the lot consistent with the grading plan and/or complete the installation of the sod and seed.
14. The city of Farmington may at our discretion use turbidity measurements as an indicator of potential noncompliance with these standards. If NTU measurements taken at a point of site stormwater discharge exceeds fifty (50) NTUs (25 NTUs for trout stream) a construction erosion control inspection of the site shall be completed. Enforcement procedures and time frames to correct noncompliant conditions shall be as specified by these standards and NPDES general construction permit. Exceedance of the turbidity indicator alone shall not constitute noncompliance. Sampling and analysis of turbidity shall be completed as follows:
(a) Samples should be taken from the horizontal and vertical center of the outflow, and care should be taken to avoid stirring bottom sediments.
(b) A written narrative of site specific analytical methods and conditions used to collect, handle and analyze the samples will be completed and kept on file, and a chain of custody record kept if the analysis is performed at a laboratory.
(c) All sampling shall be collected by "grab samples" and the analysis of these samples must be conducted in accordance with methodology and test procedures established by EPA method 180.1 or standard method 2130B.d. Other sampling protocol include:
(1) Sample containers should be labeled prior to sample collection.
(2) Sample should be well mixed before transferring to a secondary container.
(3) Sample jars should be cleaned thoroughly to avoid contamination.
(4) Sampling and analysis of receiving waters or outfall below the minimum detection limit should be reported at the detection limit. (Ord. 015-691, 3-2-2015)