Location:
Route 215 (approximately 15 miles
in length) beginning at the junction with Route 23 (near Cass) to Oark in the
Ozark National Forest (also designated as U.S. Forest Highway 65). The route
is north of I-40, with Arkansas Route 23 as the western terminus, in NW
Arkansas’ Franklin and Johnson Counties
(generally 45 miles East-NE of Fort Smith and 35 miles South-SE of
Fayetteville).
Project
Description:
Route 215 is an improved 2-lane
facility of approximately 15 miles in length following along the Mulberry River
(providing a scenic overlook) with its steep slopes and providing access to the
Redding and Wolfpen Campgrounds in the White Rock Wildlife Management Area of
the Ozark National Forest.
Purpose and Need Summary: (abstracted from the project’s 1994 Environmental
Assessment)
The previously existing route was not adequate for the current or
anticipated future traffic. The travel lane was too narrow, the surface rough
(gravel), and an unnecessary amount of dust and siltation were being produced,
all of which detracted from the personal experience and water quality of the
streams and river in the area. The road provides access to the Mulberry River Valley
for local residents, recreationists, and other forest users. The road provides
access to campgrounds, hiking trails, and scenic views of the Mulberry River.
The Mulberry River is very popular among canoeists and it is highly regarded as
a smallmouth bass river. Hunters also heavily use the National Forest during
hunting season. The reconstructed roadway is meant to reduce dust and siltation
thereby enhancing the personal experience and improving the water quality of
the area.
History of the Project:
The intended project’s
environmental assessment was completed in 1994 based on a route to be
constructed on existing alignment. The
improvement was specified to be two 10’ paved travel lanes with 2’ shoulders
where possible, or curb and gutter where necessary. The route was split into five project segments (beginning near
Cass and extending eastward). The first
two segments were the design responsibility of the Arkansas Highway and
Transportation Department and they were open to traffic in 1997 and 1998,
respectively. The last three segments are the design responsibility of the
Eastern Federal Lands Highway Division (FHWA). The third segment is near
completion and the fourth is under construction. It is anticipated that the
final segment will be let in 2003. Once
all five segments are complete the entire roadway is to be incorporated into
the state’s highway system. The
upgrading of the corridor is part of the Forest Service’s master plan to
provide a scenic drive across the Ozark National Forest.
Context-Sensitive Factors:
Several principles were
established for erosion and sediment control during and after
construction. The visual environment of
the forest, the viewscape from the Mulberry River, and the vistas overlooking
the river were deemed extremely important to maintain and enhance. Improvement measures include: revegetation
of cut and fill slopes; location of borrow and waste areas so as to not be
visible from the river; and use of native stone to the largest extent possible
for retaining walls, gabion walls, riprap and ditch lining. Because of the
potential instability of the mountain, cuts were kept to a minimum. An
additional requirement was to leave in place stone retaining walls at culverts
and even a rock box culvert with large stone slabs (it has been covered over by
the new roadway and its sides have been extended with pipe). The roadway
alignment closely tracks the existing land contours to minimize both cuts and
fills.
Highway
Agency (Partnerships):
Arkansas State Highway and
Transportation Department
Federal
Highway Administration (specifically the Eastern Federal Lands
Highway Division)
Resource Agencies Involved:
U.S. Forest Service
National Park Service
Arkansas Natural Heritage Commission
Arkansas Dept. of Environmental
Quality
Arkansas Natural and Scenic River
Commission
Significant
Environmental Issues:
Natural Environment:
The major issues
include the fact that the road is in a national forest and follows a
river. Concerns were for preserving
and enhancing scenic quality as well as water quality. Design principles included following the
terrain and creating as little disturbance as possible with the alignment and
using natural materials to the largest extent possible. The roadway provides improved access to
forest uses and an improved view from the roadway, while also protecting the
viewshed of the Mulberry River below.
Design
Issues and Special Features:
Design Speed:
A 20 mph design speed was used to minimize changes to the existing alignment and 40 mph used elsewhere, when possible.
Right-of-Way:
There were no recorded existing right-of way limits. The roadway project was mandated to be on the existing alignment with minimal changes to the existing landscape.
Clear Zones:
Various combinations of components were used including barrier walls, curb and gutter, and guardrail
Number of Lanes:
2-lanes
with discontinuous 2’ paved shoulders
Lane Width:
10’ paved
travel lanes
Special Features:
Design speed chosen to allow use of much of the existing gravel road alignment. Retaining structures were used adjacent to cuts and fills in lieu of slope flattening. Native stone was used extensively for veneer on crash worthy walls, riprap/gabion retaining walls and ditch lining. Controlling erosion and sediment during and after construction has been a major concern. The design maintains the visual quality of the viewscape from the Mulberry River and provides for scenic overlooks of the forest and river for the roadway traveler.
Adjacent land use:
Primarily forest (hunting and
hiking), river (fishing and canoeing), and campgrounds. The Mulberry River
falls under the protection of the federal Wild and Scenic Rivers Act and is
listed in the Arkansas Natural and Scenic Rivers Registry.
Project
Development Schedule and Costs:
Design: (Design
costs are not available.)
Construction:
Segment 1 $3,822,144 completed
7/97
Segment 2 $3,167,260 completed
10/98
Segment
3 $1,803,888 under construction (near complete)
Segment
4 $4,497,577 under construction (let 9/01)
Segment
5 $3,750,000 to
be let 2003
Project
Outcome and Lessons Learned:
The Arkansas State
Highway and Transportation Department is knowledgeable of context-sensitive
design practices. However, this project
extended the parameters of past initiatives/experience especially for the
design of a secondary road. The
‘client’ certainly ‘did not want a flat straight road’. The preliminary design for the first segment
underwent significant revision as the designers began to appreciate the full
extent of the client’s requirements. In
order to preserve and protect the natural environment and create a built
roadway environment that was to be esthetically pleasing design speed, roadway
geometric features and natural materials were brought together. Some of the built features that look simple
are made possible by using geotechnical design methods and special materials
that cannot be seen. The photographs
that accompany this case study show the results of this extraordinary roadway
development effort.
Route
Diagram and Photographs: (see attached)
Information
Contact(s):
Steve R. Mitchell, AICP
Senior
Planner
Arkansas
State Highway and Transportation Department
501
569-2065
Steve.Mitchell@ahtd.state.ar.us
Design Engineers:
Claude Klinck, PE
Arkansas State Highway and
Transportation Department
501 569-2531
Dave Webber, PE
Eastern Federal Lands Highway
Division (FHWA)
703 404-6315