The Triangle boasts hundreds of miles of greenway, including more than 100 miles of walking and biking trails. The Crabtree Creek Greenway is designed to link the City of Raleigh’s greenway system with Umstead State Park in Cary. WithersRavenel has provided planning, engineering, and design services for two major portions of the greenway.
For the original segment of the greenway, WithersRavenel evaluated potential trail alignments immediately west of Duraleigh Road in Raleigh. Portions of this land have mountainous terrain, which requires multiple vertical alignments. Designing trails next to streams usually does not have grades over 1%. However, one trail by Crabtree Stream had a 23% grade. WithersRavenel created a computer model to simulate walking on the trail. This was done to check if it met ADA guidelines for accessibility.
Additionally, WithersRavenel provided surveying, design, easement maps, permitting and bidding support, and post-construction-award services for the original trail segment. The permitting effort included:
- Conditional Letter of Map Revision (CLOMR)
- Clean Water Act Section 401/404 permits
- Encroachment permits
- Erosion and sediment control permits
WithersRavenel worked with the Federal Emergency Management Administration (FEMA), U.S. Army Corps of Engineers (USACE), North Carolina Department of Water Resources Division of Water Quality, and the North Carolina Department of Transportation.
The other main part of the greenway is a 2.25-mile segment. It runs from Black Creek in Morrisville. It goes along the southern edge of Lake Crabtree in Cary. Finally, it ends at Evans Road and Aviation Parkway in Morrisville. WithersRavenel provided surveying, hydraulics/hydrology, landscape architecture, environmental and wetland delineation, design, cost estimating, and permitting for this segment.
The WithersRavenel team built several bridges and boardwalks. This was necessary because the trail goes through floodplains and wetlands. A key part of the design is a new boardwalk. It is 730 feet long and goes over the southern part of Lake Crabtree, where Black Creek flows into the lake. This provides an out-of-the-ordinary trail experience in an area where trail users enter Umstead Park near the Weston development in Cary.
The American Council of Engineering Companies (ACEC) of North Carolina awarded WithersRavenel an Engineering Excellence Award for its innovative achievements on the recently completed 1.7-mile section of the Crabtree Creek Greenway that runs along Lake Crabtree in Cary.