CY33-25

Request of Larry Krmpotich for a conditional use permit to allow the installation of a retaining wall in an area having a slope equal to or in excess of 17.6 percent. The subject property is described as Lot 3, Block 1, Mayan Way Subdivision Phase 3, Mankato. (208 Mayan Way).

The anticipated date of City Council action is August 11, 2025. 

The applicant is the property owner, Larry Krmpotich. 

The applicant is seeking a conditional use permit to allow work in an environmentally sensitive area, a slope. 

The subject property is located at 208 Mayan Way and is legally described as Lot 3, Block 1, Mayan Way Subdivision Phase 3, Mankato. 

The property is the location of an existing residential property. 

The property is zoned R-1, one family dwelling district. 

The site includes environmentally sensitive areas, including slopes/ravines, wooded areas, and a stream that traverses the very northern portion of the subject lot. 

The property is currently served by public utilities and changes are not proposed with this request. 

Mankato City Code Chapter 10, Article X, Division 2, Sec. 10-1499 related to Environmentally sensitive areas - slopes can be found here: https://library.municode.com/mn/mankato/codes/code_of_ordinances?nodeId=CH10LAUSDE_ARTXSTGEAP_DIV2SPPRAPSPPECOUS_S10-1499ENSEARLO

Mankato City Code Chapter 10, Article X, Division 2, Sec. 10-1501 related to Environmentally sensitive areas - woodlands, can be found here: https://library.municode.com/mn/mankato/codes/code_of_ordinances?nodeId=CH10LAUSDE_ARTXSTGEAP_DIV2SPPRAPSPPECOUS_S10-1501ENSEAROO

Mankato City Code Chapter 10, Article XI, Division 3, relating to Conditional Use Permits can be found at this link: https://library.municode.com/mn/mankato/codes/code_of_ordinances?nodeId=CH10LAUSDE_ARTXIADEN_DIV3COUSPE 

 

The Site Plan and Traffic Advisory Committee reviewed the item at their July 8, 2025, meeting and provided the following comments. The applicant's responses are also included below in italics. 

1. The applicant shall provide signed engineered plans along with plans indicating if any trees will be removed. The applicant shall be aware that tree replacement may be necessary if any trees are removed. Applicant's response: I am waiting for the revised drawings from Mark Lawton, should be today. Only expecting one tree to be moved. It is relatively small, I had planted it a few years ago.
2. The applicant shall provide a grading plan clearly showing slope improvements to protect the retaining wall and prevent future erosion. Applicant's response: The contractor and I have discussed extensive use of geogrid for wall strengthening, and additional fill at the base of the wall to prevent erosion of the ravine near the wall.
3. The applicant shall provide a drainage plan showing best practices for discharging storm pipes. Applicant's response: I will be re-digging my house drain tiles and consolidating them to a solid drain tile and extending it to the bottom of the ravine to minimize erosion. 
4. Applicant shall make the notification fee payment on the online portal, if not already complete. Applicant's response: Paid.

Larry Krmpotich, property owner, is requesting a conditional use permit to allow the installation of a retaining wall in an area having a slope equal to or in excess of 17.6 percent. The subject property is located at 208 Mayan Way and is legally described as Lot 3, Block 1, Mayan Way Subdivision Phase 3, Mankato.

The Mankato City Code requires a conditional use permit for work that occurs in environmentally sensitive sloped areas. Chapter 10, Article X, Division 2, Sec. 10-1499 states, "All cut, fill, and development activities on a slope equal to or in excess of 17.6 percent may be permitted only as a conditional use." The Code goes on to state that, in addition to the requirements for a conditional use permit, the plans for improvement should be signed by a registered engineer. 

Existing site conditions show an existing retaining wall on the easterly side of the property, landscaping blocks in the rear yard as well as two existing drain tile lines running from the existing house to the ravine area.  The applicant has indicated that the sloped/ravine area is eroding and desires to address the ongoing concern.

Plans submitted for the planned site improvements show the installation of a new retaining wall in the rear yard of the subject property, which is proposed to be constructed in an environmentally sensitive area meeting the definition of a slope. The plans provided identify the environmentally sensitive area as "top of slope" and the planned retaining wall encroaches into said area, thus the conditional use permit request. 

Plans show a new retaining wall spanning almost the entire width of the lot, running from west to east on the lot, and connecting with the existing retaining wall already located on the eastern side of the subject parcel. The engineering plans, S1, indicate “Corrected Property Line Locations." A recommended condition is included herein that, prior to work beginning, the property lines should be identified by a professional surveyor. Like a fence, a retaining wall is allowed up to, but not on or over the property line. A recommended condition included herein that, if encroachments on the adjacent property are necessary for construction and installation purposes or other, for the installation of the retaining wall, the applicant shall obtain written approval prior to work beginning. 

The new retaining wall is outlined to be 4' X 2' X 2', dry stack "County Rib" blocks. Plans show a variable wall height based on the existing topography of the area, and both an engineered low wall section and regular section detail are provided for these conditions. The engineered plans represent a 15' wide surcharge area for the wall construction and engineering on the southerly side of the new wall. Regrading of the existing yard, for a maximum of 3/8 inch per foot and sloping towards the new wall, is also shown.

The plans indicate that the wall will be constructed using “Rib Rock” type landscaping block retaining wall materials. Engineering plans show that there will be "geogrid SRW-7" installed as part of the new retaining system. According to the SRW products website, geogrid is," uni-directional geogrid composed of high molecular weight, high-tenacity multifilament polyester yarns that are woven into a stable network placed under tension. SRW geogrids can withstand biological degradation and are resistant to naturally encountered chemicals, alkalis and acids. These are the best geogrids for soil reinforcement applications such as retaining walls, steep slopes, embankments, and more to add strength and longevity to hardscape projects." The SRW Products website states that this geogrid product adds strength and longevity to retaining walls, provides excellent stress transfer and helps prevent wall failure.  

Plans also show drain tile running parallel with the proposed retaining wall as well as 4" PVC drain tile projecting through the retaining wall. The plans show the three drain tile lines currently in the backyard to be re-built and connected to the drain tile located behind the new retaining wall. A recommended condition is included that requires that all drainage from the subject property that traverses the retaining wall be routed to outlet to the bottom of the ravine/water source. The reason for this recommended condition is to avoid erosion that could potentially be caused due to the outlet of the pipe mid-sloped area. 

The subject property is also located in an area identified on the City's environmentally sensitive areas map and the Code as "Woodlands". The applicant has indicated that the removal of one tree will be necessary in order to accommodate the installation of the new retaining wall. The City Forester has reviewed the request and determined that the removal of the existing tree is appropriate and that additional tree plantings in the area are not appropriate given the new wall. 

The plans show protection of the existing ravine/sloped area with a silt fence. A recommended condition is included herein that, prior to work occurring, and after the installation of the BMP's, such as the silt fence, a pre-construction meeting be held onsite with the owner, the contractor and City staff. A recommended condition is also included that, prior to work occurring, the applicant should obtain a building permit. 

Staff submits the following findings with respect to the Conditional Use Permit request: 

1. The proposed use, an existing residential dwelling, is not proposed to change. The fill, cut and development activities within the slope area equal to or in excess of seventeen point six (17.6%) percent is considered a conditional use permit in Mankato City Code Chapter 10, Article X, Division 2, Sec. 10-1499. 
2. The request is in keeping with the comprehensive planning policies of the City as the underlying land use plan identifies this parcel as "Low Density Residential", which is in keeping with this request that is not seeking any changes to the current use of the property.  
3. The proposal does not interfere with or diminish the use of property in the immediate vicinity.   
4. The primary structure will continue to be served by public facilities and services, and no utility service provider changes are proposed with this proposal. 
5. The proposal does not cause undue traffic congestion as no changes are proposed to the public street system. 
6. There are no known historical or architectural resources on the site. 
7. The site contains bluffs and woodlands as natural or environmental features on the site. With the recommended conditions, it is intended that impacts to these areas will be corrected and minimized. 
8. It will not cause a negative cumulative effect and effect on the City as a whole. 
9. To the extent known, the development, when considered with the recommended conditions, conforms with all other applicable regulations of the district, and other applicable ordinances. 
10. The proposal will not jeopardize the public's health, safety, or general welfare.

Staff recommends approval of the requested conditional use permit with the following conditions: 

1. All drainage from the subject property, including, but not limited to, retaining wall drainage, skating rink drainage, roof and gutter drains, shall outlet to the bottom of the ravine. Additional bluff disturbance when installing said drain pipe is prohibited. 
2. The applicant shall obtain written approval from the adjacent property owners if encroachments are necessary for the construction and installation, or other, of the proposed retaining wall. 
3. Prior to work occurring, and after the installation of the BMP's, such as the silt fence, a pre-construction meeting shall be held onsite with the owner, the contractor and City staff.
4. Prior to work occurring, the applicant should obtain a building permit. 
5. Prior to beginning work, the property should have the property lines staked and visible for an inspector and these stakes/pins should be visible during a pre-construction meeting.