STAFF REPORT

Planning and Development Committee, May 14, 2008

Green Level Stream Restoration and Greenway Project (PR08-28)
Consideration of approval of the Green Level Stream Restoration and Greenway Project Plan

Speaker:  Mr. Doug McRainey
 

From:  Mary G. Henderson, Director, PRCR
Prepared by:  Paul Kuhn, Senior Parks Planner

Approved by:  William B. Coleman, Jr., Town Manager

Approved by:  Benjamin T. Shivar, Assistant Town Manager

Introduction

In 2007 the Town of Cary was awarded $280,020 from the Natural Resources Conservation Service of the United States Department of Agriculture for the purpose of completing an open space, stream restoration and greenway plan in Green Level along the Flat Branch tributary.  This grant was obtained to plan for the protection of this riparian corridor’s natural resources ahead of development.  Specifically, the project extent is within the Jordan Lake Watershed in west Cary between Green Level Church Road and Green Level West Road, a distance of two miles. This is the second grant the Town has received from USDA to complete a similar study, with the first being the White Oak Creek Stream Restoration and Greenway Study, completed in March 2007.

Planning Process

The planning for the Green Level study was initiated in August 2007.  It was completed by the firm of Baker Engineering and their sub-consultant HadenStanziale. The planning process took approximately nine months to complete.  Public input was a part of the planning process and two public meetings were held to seek public input on the study.

Summary of Plan

The study area includes a riparian corridor that is located west of Green Level Church Road, which includes the historic Green Level area of the Town of Cary.  Residents of the area have identified this riparian corridor by the name "Flat Branch."  While most of the study area is forested, the watershed contains multiple land uses including active farmland, low density residential, and two parcels that are currently under development. The initial phase of the project included an inventory and analysis of the base data. It involved the collection of watershed and geographic information system (GIS) data. Field assessments focused on classifying stream reaches within the project boundary, identifying bank erosion on project reaches, as well as classifying natural communities and developing a farmland/land use GIS database for the study area. Identification of the greenway corridor alternatives was performed by HadenStanziale and focused on potential trail routings based upon viewsheds, educational points of interest, potential stream and wetland crossings, and potential easement requirements. Potential parcels for open space and farmland preservation were also identified.

The total length of stream reaches assessed in the study area was approximately 1.5 miles. While the majority of the evaluated stream reaches were relatively stable, with most maintaining natural access to their floodplains, the lower 1,700 linear feet (LF) of Flat Branch was more incised and had moderate to high bank height ratios, which correspond to a greater risk of bank erosion during flood events.  It is this lower segment of the Flat Branch that is recommended for Priority Level I and II stream restoration. These levels of restoration address dimension (cross-section), pattern (sinuosity), and profile (channel slope and bed form diversity). This approach will allow the stream to reestablish itself with its floodplain and restore a meandering channel. This restoration has been designed to complement previously designed stream restoration immediately downstream of the project area, as presented in the White Oak Creek Stream Restoration and Greenway Project, Design Alternatives Report of May 2007. A preliminary estimate of the construction cost for the stream restoration component is $274,000.

In terms of the proposed greenway, a 6,649 linear foot greenway corridor was developed based on an evaluation of the routing options and discussions with staff, state, and local agencies.  The greenway, as proposed, would extend from Green Level Church Road in the north (southern edge of Weldon Ridge and Southbridge PDD) to Green Level West Road in the south. The majority of the greenway follows a proposed sewer line that is planned to run adjacent to Flat Branch for the lower 5,000 feet of the project area. While a final sewer alignment is not available at this time, the preferred alignment was evaluated and appears to meet the needs of the project in this area.  It will also parallel the planned Weldon Ridge Boulevard to avoid anticipated future development along this parcel. In this respect, the greenway corridor has been planned to minimize cost, address community needs, and avoid landowner conflicts as practicable. The proposed greenway ends at its intersection with Green Level West Road, where it will cross the road and link with the next phase of the White Oak Creek Greenway which will in turn link directly to the American Tobacco Trail. A trailhead is planned at the recently completed pump station on Green Level West Road at the trail intersection of both the White Oak Creek and Flat Branch Greenways. Construction cost for the greenway is estimated at $851,600.

The study recommends that a substantial amount of the buffer located between the Flat Branch tributary and the future extension of the Weldon Ridge Boulevard be preserved as open space.  In addition, potential farmland was assessed for protection and the study recommends several additional parcels within the watershed for open space and/or farmland preservation. The attached map indicates which parcels are recommended for protection. Cost estimates for the acquisition of these parcels were not completed as part of this study.

The study was presented to The Greenway Committee at its February 2008 meeting and the PRCR Advisory Board and its March 2008 meeting, and both unanimously recommended approval of the plan.

Implementation:  This plan does not include an implementation strategy.

Fiscal Impact:  Since this project was a study, there were no operating impacts other than the staff time required to manage the project. The entire study was funded through the grant.

Staff Recommendation:  Staff recommends approval of the Green Level Stream Restoration and Greenway Plan.