Disposition Summary

Approve the variance to allow a T-turnaround in lieu of a cul-de-sac at the western terminus of Signal View Road.
A. The T-turnaround on this stub street will allow for future access to the adjacent properties and allow for less grading into an area with steep slopes and a closed contour (possible sinkhole).
B. The road stub-out was a requirement of the 2022 concept plan approval, and the T-turnaround will allow for the conversion to a standard road cross section when the road is extended into the adjacent property.
C. The granting of the variance will not be detrimental to public safety, health, or welfare because the turnaround meets the American Association of State Highway and Transportation Officials (AASHTO) standards.

Approve the Concept Plan subject to 14 conditions.

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Staff Recommendation

Approve the variance to allow a T-turnaround in lieu of a cul-de-sac at the western terminus of Signal View Road.
A. The T-turnaround on this stub street will allow for future access to the adjacent properties and allow for less grading into an area with steep slopes and a closed contour (possible sinkhole).
B. The road stub-out was a requirement of the 2022 concept plan approval, and the T-turnaround will allow for the conversion to a standard road cross section when the road is extended into the adjacent property.
C. The granting of the variance will not be detrimental to public safety, health, or welfare because the turnaround meets the American Association of State Highway and Transportation Officials (AASHTO) standards.

Approve the Concept Plan subject to 14 conditions.

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1. Connection to sanitary sewer and meeting any other relevant requirements of the utility provider.
2. Provision of street names consistent with the Uniform Street Naming and Addressing System within Knox County (County Ord. 91-1-102).
3. If during design plan approval or construction of the development, it is discovered that unforeseen off-site improvements within the right-of-way are necessary as caused by the development, the developer will either enter into an MOU with the County for these improvements or reimburse the County for their direct expenses (if completed by County crews) to make corrections deemed necessary.
4. All sidewalks and crosswalks within the public right-of-way shall meet the applicable ADA standards. The design details shall be worked out with Knox County Engineering and Public Works during the design plan phase.
5. Providing a mid-block crosswalk at the intersection of Road 'M' and Mount LeConte Drive per the requirements of Knox County Engineering and Public Works during the design plan phase.
6. Implementation of the street and intersection improvement recommendations as outlined in the Couch Mill Road Subdivision Transportation Impact Study prepared by AJAX Engineering (revised 2/18/2022), as revised and approved by the Knox County Department of Engineering and Public Works and Planning staff (see Exhibit C). The design details and timing of the installation of the improvements shall be worked out with the Knox County Department of Engineering and Public Works during the design plan stage for the subdivision.
7. Meeting all application requirements of the Knox County Stormwater Management Ordinance (Chapter 26, Article VI of the Knox County Code), including but not limited to, obtaining approval from the director of the Department of Engineering and Public Works to modify or fill any sinkholes (closed contours). If the approved geotechnical report determines that a closed contour identified by Knox County Engineering and Public Works is not a sinkhole, the certification to be provided by Knox County Engineering and Public Works must be placed on the final plat and sealed by the applicant's engineer.
8. Providing the location of all sinkholes/closed contours and the 50-ft buffer (building setback) on the final plat per Section 3.06.B of the Subdivision Regulations.
9. If any building construction is proposed within the 50-ft buffer area around the designated sinkholes/depressions (including the depressions), a registered engineer must prepare a geotechnical report to determine soil stability. That report must be submitted to the Knox County Department of Engineering and Public Works for consideration. Any construction in these areas is subject to approval by the County following a review of the report. Engineered footings must be designed for these areas. For those lots that do not have a building site outside of the 50-ft buffer, approval by Knox County will be required prior to final plat approval. The sinkholes/depressions and 50-ft buffer shall be designated on the final plat even if they are approved to be filled.
10. Providing the proposed road stub-out at the western terminus of Signal View Road and notification of future street connections per Section 3.04.C.2.b. & d. of the Subdivision Regulations.
11. The temporary turnaround at the western terminus of Signal View Road must meet the American Association of State Highway and Transportation Officials (AASHTO) design standards, as required during the design plan phase by Knox County Engineering and Public Works. The portions of the turnaround located outside of the 50-ft public right-of-way may be put in an easement.
12. Meeting all applicable requirements of the Knox County Zoning Ordinance.
13. Meeting all applicable requirements of the Knox County Department of Engineering and Public Works.
14. Prior to certification of the final plat for the subdivision, establish a property owners association that will be responsible for the maintenance of the common areas, amenities, and drainage system.

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This proposal is for 13 additional house lots in Phase 3 of The Haven at Hardin Valley Subdivision (formerly Brown Property-Couch Mill Road), increasing the total to 118 house lots in this phase, and 372 lots in the entire subdivision. The subdivision was originally approved in March 2022 (1-SA-22-C / 1-D-22-UR), and final plats for Phase 1 were recorded in 2024 (135 house lots). The first unit of the next phase, Phase 2A, is also on this agenda for approval (6-SF-25-F), comprising 28 lots.

A revised concept plan application is part of this request because there will be 6 or more new lots, which is the threshold for requiring a concept plan. Since all the new lots are in Phase 3, the revised concept plan is not required for Phases 1 and 2. The road layout and location of lots remain largely unchanged. To accommodate the additional lots, the typical lot width is now 55 ft, with a few exceptions that are larger, whereas the original plan had a mix of lot widths of 55 ft and 65 ft. In addition, three lots were added to the western end of Signal View Road.

TRANSPORTATION IMPROVEMENTS
The developer has entered into a Memorandum of Understanding (MOU) with Knox County regarding the off-site improvements to be completed in partnership with the county. This includes a roundabout at the intersection of Sam Lee Road, Swafford Road, and Steele Road, and a sidewalk along Couch Mill Road/Sam Lee Road, from the subdivision's western access point to the aforementioned roundabout.

SINKHOLES
There are several large sinkholes on this property. The dashed line around the sinkholes represents the 50 ft buffer from the uppermost closed contour of the feature required by the Subdivision Regulations (Section 3.06.B.). Each lot must have a buildable area outside of the closed contour of a sinkhole. Still, a house can be built within the 50 ft buffer if a geotechnical study prepared by a registered engineer states that building within the 50 ft sinkhole area is acceptable with engineered foundations. During the design plan phase, the uppermost closed contour of the sinkholes will be further defined, which may result in the sinkholes being larger than depicted on this Concept Plan and potentially leading to the loss of lots.

VARIANCE
The applicant requests a T-turnaround instead of a cul-de-sac at the western terminus of Signal View Road. This is intended to be temporary because this is a stub street that will provide future access to the adjacent property to the west. Staff recommend approval of this request because of the short length of this street segment (approximately 308 ft) and the limited number of houses (7). The proposed T-turnaround must meet AASHTO design standards.

HILLSIDE PROTECTION AREA
There are approximately 31.82 acres of hillside protection (HP) area in the 50.65 acres in the slope analysis. This acreage is approximately 5 acres more than stated on the concept plan for Phase 3 due to the difficulty in matching the case boundary to a development boundary that does not align with parcel lines and has several changes in direction. The slope analysis recommends a disturbance budget of 18.76 acres of the 31.82 acres in the HP area.

However, when evaluating the disturbance within the HP area, we consider the full area of development. The slope analysis, created in conjunction with the review of the 2022 concept plan, states that there are 37.48 acres in the HP area and recommends a disturbance budget of 23 acres in the HP area. Most of the HP area is located around the large sinkholes in the northwest portion of the property, which are predominantly in Phase 3. Besides the steep slopes associated with the sinkholes, the property consists mainly of rolling hills. The 2022 concept plan disturbed approximately 20.9 acres of the HP area, which complies with the slope analysis recommendations. The road layout and location of lots have remained relatively unchanged, resulting in no significant change in the disturbance area.