Review Natural Resources Aspects of Preliminary Plat for Williams Woods (Project #20-138); Case of Bill Boyum

The City has received a Preliminary Plat application for a proposed nine (9) lot subdivision on approximately nine-four (94) acres. The project involves six (6) individual parcels, all affiliated with 7363 175th Ave NW (the "Subject Property"). The Environmental Policy Board (EPB) previously reviewed the Sketch Plan for this project, but this submittal now includes more detailed plans, including While this project is only at the Sketch Plan step, which does not include detailed plans, including a Tree Inventory and Preservation Plan. 

The Subject Property is located in the R-1 Residential (Rural Developing) District and is guided as Rural Developing in the 2040 Comprehensive Plan. Minimum lot size in this district is 2.5 acres and the maximum density permitted is one unit per 2.5 acres. The Subject Property is approximately 94 acres in size and the project is only proposing nine (9) total lots, well within the allowable thresholds.

Natural Resources Inventory and Tree Preservation

The City's Natural Resources Inventory (NRI) identifies multiple moderate quality natural areas within the Subject Property, including both Oak Forest and Dry Prairie. Due to the limited number of proposed lots, the project has the potential to minimize impacts to these natural areas. While there will be some disturbance, it appears that grading will be limited mostly to the public road and house pad locations. Due to the oaks present on the Subject Property, any clearing activities will need to occur outside of April 15 to July 15 due to concerns with potential introduction of oak wilt to the area.

Due to the size of the Subject Property and the limited areas of site disturbance, the Applicant had proposed limiting the tree inventory to just those designated areas of potential impact. This approach seemed reasonable and was approved with the understanding that the project must still comply with the tree preservation standards in City Code (retaining at least thirty percent [30%] of the significant tree diameter at breast height [DBH] inches on site). 

Based on the submitted Tree Inventory and Preservation Plan, approximately 64% of the existing significant tree Diameter at Breast Height (DBH) inches will be preserved.  Again, this only includes the trees that were inventoried (only those that were in areas of proposed disturbance), there are many more trees on the Subject Property overall, meaning that an even greater percentage of tree inches are actually being preserved.

Wetlands and Floodplain

There are both wetlands and floodplain on the Subject Property. Approximately thirty (30) acres of the Subject Property contain either wetland and/or floodplain. The floodplain is designated as General Floodplain, meaning that there has not been detailed modeling done to determine Floodway and Flood Fringe boundaries. However, as long as there are no proposed buildings within the floodplain boundary, which there are not, additional modeling is not required. Staff is working with the MN DNR Floodplain staff to verify that the proposed driveways and public road are permissible (they do cross the floodplain boundary).  The developer will likely need to provide documentation that neither would create a rise of more than 0.5 feet.  Additionally, the developer will also need to provide documentation that no driveway or the public road will be more than two (2) feet below the Regulatory Flood Protection Elevation.

A wetland delineation has been completed. The Preliminary Plat does include the required sixteen and a half foot (16.5') wetland setback. There appear to be minimal impacts to wetland on Lots 3-5, simply due to needing the driveways to access buildable locations on each of the lots. Depending on the actual impacts, this may qualify under the de minimus exemption in the Wetland Conservation Act; however, that is determined by the Local Governmental Unit (LGU), which is the Lower Rum River Watershed Management Organization (LRRWMO).

Landscaping

Each of the nine (9) lots have existing trees that will be located between the proposed house pads and the public street.  Additionally, based on the amount of trees being preserved across the Subject Property, no additional plantings would be required.

All costs associated with the project are the Applicant's responsibility.

Motion to recommend approval of the Tree Inventory and Preservation Plan.