§ 5-7. Drainage.

(a)

Obstruction of drainage structure . Drainage structures that adjoin or run on, across, or through any property, may not become obstructed or fall into a state of disrepair. Drainage structures must be maintained in a state that allows for the free and unrestricted passage of water therein.

(1)

Notice to land owner to remedy conditions.

a.

Generally . Whenever the public works director, or the director's designee, shall determine that any drainage structure is obstructed, in a state of disrepair, or is not adequate, the owner of such premises shall be notified on which such condition exists or adjoins, to remedy such condition at once, so that such obstruction shall be removed and condition corrected. The existence of the condition which obstructs or impedes the free flow of surface water from, on or in the streets or drainage easements as herein set forth shall constitute a nuisance.

b.

Trees or fences in drainage easements . Whenever the public works director, or the director's designee, shall determine that any fence or tree obstructs or impedes the free flow of surface water from, or in any drainage easements, or interferes with remedying or correcting of obstructions in any drainage structure, the director or director's designee shall notify as provided in chapter 1, the owner of such premises on which such fences or trees exist, to remove said fences or trees at once. The existence of fences or trees which obstruct or impede the free flow of surface water from, or in any drainage easement, or interferes with remedying or correcting of obstructions in any drainage structure, as herein set forth, shall constitute a nuisance. The city shall not be required to pay compensation for any such fences or trees that are removed.

(2)

Failure to comply with notice. Any person who fails or refuses to comply with the notice given by the city as herein provided, within 20 days after such notice, is guilty of a misdemeanor. In addition thereto, the city shall have all rights granted to it by law to abate the nuisance.

(3)

Regrading. The regrading of a property may not adversely affect neighboring properties and shall be subject to the grading, erosion, and sediment control regulations set forth in sections 4-3(i) and 4-3(j) of this Code.

(b)

Development standards . All development and redevelopment will demonstrate compliance with the most stringent requirements of the following:

(1)

The performance standards of section 4-3(i) of this Code.

(2)

The requirements of either the Bassett Creek Watershed District or the Shingle Creek Watershed District, whichever is applicable.

(3)

Infiltration requirements.

a.

Infiltration systems must be prohibited when the system would be constructed in areas:

1.

That receive discharges from vehicle fueling and maintenance, regardless of the amount of new and fully reconstructed impervious surface;

2.

Where high levels of contaminants in soil or groundwater may be mobilized by the infiltrating stormwater. To make this determination, the owners and/or operators of construction activity must complete the MPCA's site screening assessment checklist, which is available in the Minnesota Stormwater Manual, or conduct their own assessment. The assessment must be retained with the site plans;

3.

Where soil infiltration rates are more than 8.3 inches per hour unless soils are amended to slow the infiltration rate below 8.3 inches per hour;

4.

With less than three feet of separation distance from the bottom of the infiltration system to the elevation of the seasonally saturated soils or the top of bedrock;

5.

Of predominately Hydrologic Soil Group D (clay) soils;

6.

In an Emergency Response Area (ERA) within a Drinking Water Supply Management Area (DWSMA) as defined in Minn. R. 4720.5100, Subp. 13, classified as high or very high vulnerability as defined by the Minnesota Department of Health;

7.

In an ERA within a DWSMA classified as moderate vulnerability unless the permittee performs or approves a higher level of engineering review sufficient to provide a functioning treatment system and to prevent adverse impacts to groundwater;

8.

Outside of an ERA within a DWSMA classified as high or very high vulnerability unless the permittee performs or approves a higher level of engineering review sufficient to provide a functioning treatment system and to prevent adverse impacts to groundwater;

9.

Within 1,000 feet up-gradient or 100 feet down gradient of active karst features; or

10.

That receive stormwater runoff from entities regulated under NPDES for industrial stormwater; automobile salvage yards; scrap recycling and waste recycling facilities; hazardous waste treatment, storage, or disposal facilities; or air transportation facilities that conduct deicing activities.

(4)

Mitigation provisions. There may be circumstances where the permittee or other owners and operators of a construction activity cannot cost effectively meet the conditions for post-construction stormwater management for TSS and/or TP required by the city's MS4 permit (Part III.D.5.a(2)) on the site of the original construction activity. For this purpose, the permittee shall identify, or may require owners or operators of a construction activity to identify, locations where mitigation projects can be completed. The following conditions must be met:

a.

Mitigation project areas are selected in the following order of preference:

1.

Locations that yield benefits to the same receiving water that receives runoff from the original construction activity,

2.

Locations within the same Department of Natural Resource (DNR) catchment area as the original construction activity.

3.

Locations in the next adjacent DNR catchment area up-stream.

4.

Locations anywhere within the city's jurisdiction.

b.

Mitigation projects must involve creation of new structural stormwater BMPs or the retrofit of existing structural stormwater BMPSs, or the use of a properly designed regional structural stormwater BMP.

c.

Routine maintenance of structural stormwater BMPs already required by the city cannot be used to meet mitigation requirements.

d.

Mitigation projects shall be completed within 24 months after the start of the original construction activity.

e.

The city shall determine, and document, who is responsible for long-term maintenance on all mitigation projects.

(5)

Linear redevelopment projects. A net reduction from pre-project conditions (on an annual average basis) of: stormwater discharge volume, total suspended solids, and total phosphorus.

a.

Where the lack of right-of-way precludes the installation of volume control practices that meet the conditions for post-stormwater management in Part.III.D.5a(2) of the city's MS4 permit, the permittee shall ensure that a reasonable attempt be made to obtain right-of-way during the project planning process.

b.

Exceptions for stormwater discharge volume will be made only under the following circumstances:

1.

The owner and/or operator of a construction activity is precluded from infiltrating stormwater through a designed system due to any of the infiltration related limitations described in subsection (b)(2) in this code, or

2.

The owner and/or operator of the construction activity implements, to the MEP, volume reduction techniques, other than infiltration on the site of the original construction activity that reduces stormwater discharge volume, but may not meet the conditions for post-construction stormwater management in the MS4 permit.

(Code 072684; Ord. No. 15-13, § 1, 12-14-2015; Ord. No. 18-17, § 1, 2-25-2019; Ord. No. 19-03, § 1, 4-22-2019)