The document provides a preliminary plan for removing and revegetating roads at Robles Pass Preserve to reduce environmental impacts. The plan involves a 4-phase approach: 1) Signage and planting at the entrance. 2) Revegetating the upper bedrock section. 3) Filling the central section and planting. 4) Working from top to bottom with erosion controls and planting. Methods include decompacting soil, installing water structures, and replanting with native species to stabilize the soil and restore habitat over time. Documentation of progress will ensure the plan's goals are met.

1. Preliminary Plan for the Road Removal and Revegetaion
Demonstration Project at Robles Pass Preserve
Prepared by
Steven Steinberg
Master of Landscape Architecture Candidate
for
Pima County Natural Resources, Parks and Recreation

2. Table of Contents
Section 1. Road Removal Strategies
1.a Why Remove Roads?
1.b What is road removal?
1.c Erosion control
1.d Revegetation.
1.e Camouflage
1.f Preventing continued illegal use
Section 2. Road Removal Plan for Robles Pass
2.a
2.b
2.c
2.d
Introduction
Plan Outline
General Site Analysis Guidelines
Robles Pass Site Analysis
Roads
View Sheds
Vegetation
2
3
4
5
6
7
Section 3. Road Removal Procedure
8
9
10
The Plan
Phase I
Phase II
Phase III
Phase IV
Aerial Photograph of the Project Road
References
11
12
13
Photos
Figures 1,2
Figures 3,4
Figures 5-8
Figures 9-12
Figures 13,14
Figure 15
5
7
8
9
11
12
1

3. Section 1. Road Removal Strategies
1.a Why Remove Roads?
Roads may have negative impacts in several areas:
o
o
o
Environmental
Hydrologic processes (Luce, 2002)
 Compaction Reduces soil infiltration
 Concentrating water through road drainage structures
 Converting subsurface flow to surface flow
Watershed disruption
 Soil erosion and gully formation.
 Sediment runoff into streams.
Ecological (Wisdom, 2000).
 Direct loss of Habitat
 Habitat fragmentation
 Increased human impact, as a result of improved access.
Aesthetic
 Negative viewsheds
 Noise
1.b What is road removal?
It is a process of remediation whereby unwanted roads are put out of service.
There are three categories of road removal:
o
o
o
Closure
Decommissioning
Obliteration
Road Closure consists of blocking the entrance of an unwanted road.
Three common methods are:
 Installing a gate
 Building a berm
 Cutting a ditch.
Road closure is the least expensive method, but also least effective for
keeping out motorized vehicles (Roads Scholar Project 1996). It is most effective
if the entrance is camouflaged.
Decommissioning is utilized when there is a need to close a road temporarily,
with the option of reopening it at some future date.
The process consists of:
 Outsloping the road bed.
 Removal of culverts and stream crossings.
 Removal of inboard ditch.
2

4.  Installing cross drains and water bars.
Obliteration is the complete removal and recontouring of the road bed.
 Cut outslope to original grade. Original grade can be located by (Merrill,
Casaday 2001):
 Visual inspection while digging
 Look for differences in soil layers.
 Visual comparison of the surrounding slopes
 Place fill against cut bank.
 Form to original contour with blade.
 Rip top layer of soil
 Aeration
 Decompaction
1.c Erosion control
Whichever means of remediation is chosen, erosion must be controlled. Often there is an
initial increase in soil loss until the system stabilizes (Switalski, et al. 2004).
Methods of erosion control.
Ripping involves scraping and or furrowing the top layer of ground with a
bulldozer or other equipment.
 By decompacting and roughening the surface, the soil, ripping achieves
several results
 Higher infiltration rates of rain water.
 Aeration of soil for improved vegetation establishment
 Reduction of weed growth.
 Effectiveness of ripping depends on:
 Stability of the slope (Bloom 1998),
 Soil texture (Luce 1997),
 Use of soil amendments ( Cotts et al. 1991)
o Controlling storm water flow
 Diversion and retention structures divert flow to stable drainage path
(Zeedyk Jansens, 2006)
 Swales and berms are trenches, with a mound on the downhill side,
built along the contour to hold water,
 Rolling dips- a series shallow and wide dips, used where there is
traffic
 Diversion drains are similar to swales and berms, except they are
designed to drain the water away from the site.
 Micro-catchments are small crescent shaped depressions and berms
used to hold water. Can be used for planting.
 Water slowing structures
 Rock or log lines on contour slow water flow and allow for increased
infiltration.
 Mulch
 Protects soil from drying by sun and wind
o
3

5. 

o
Adds organic material.
Horizontal mulch: branches and limbs laid across the road.
Revegetation stabilizes the soil.
1.d Revegetation
Revegetation is the key to successful road removal and habitat remediation.
Successful revegetation will remediate the negative impacts of roads.



Environmental
 Stabilizing soil
 Improve hydrologic processes through water flow regulation
Ecological
 Habitat restoration
 Mature trees, shrubs, and cacti block access for vehicles and provide
shelter for wildlife.
Aesthetic
 Camouflage road scars
Revegetation methods
Many of the strategies used for erosion control are essential for successful revegetaion.
o Soil decompaction and aeration
Incre
ased water retention, infiltration, and permeability.
 Structures to hold and slow water flow.
 In addition to the structures described in the erosion control section,
digging pits of various sizes will catch water and increase overall soil
moisture (Bagley, Scott, 1999).
o Seeding
 Direct seeding is not reliable in desert environments (Bainbridge, and
Virginia, 1990). It is highly dependent on rainfall unless extensive
sprinkling systems are set up.
 Seeding is a secondary longer term process that will occur naturally over
time, once the system stabilizes.
 Replenishing the road surface with soil from the surrounding area will
help establish a seed bank. (HÄLBICH, T.F.J., 2003).
 Seeds must be from native species that are found in the local area.
o Replanting salvage from the surrounding area, if available and abundant. For
example Opuntia species are good candidates for desert revegetaion.
o Transplanting nursery stock.
 Larger plants are more successful (Bagley, Scott, 1999).
 Irrigation, if possible to establish plants.
 Use rain water harvesting methods.
 Plant in late fall to early spring.
 Deep pipe irrigation (Bainbridge, Fidelibus, and MacAller 1995).
4

6. 1.e Camouflage can be used to lessen the visual impact of the road scar until the
vegetation matures.
o Vertical mulch: “planting” dead limbs, branches, and clumps of dried grass
Vertical mulch has many other advantages (Bagley, Scott, 1999).
 Reduces wind speed.
 Facilitates deposition of blowing soil and organic litter.
 Creates safe sites for plant establishment.
o Breaking up the straight lines at the road edges.
1.f Preventing continued illegal use by off road vehicles is essential to the
success of the project. While signs might work for most, there are always those who will
not respect barriers and the young plants and structures can easily be destroyed. The open
nature of the desert environment allows for alternative access to the existing roads. As
can be seen in figures 1 and 2 partial barriers are not effective. They can lead to more
habitat destruction when illegal users drive around them in search of new routes.
o A perimeter fence that cannot easily be breached, such as cable
o Step over gates
o Strict enforcement with fines and confiscation of vehicles.
Fig 1. Ineffective barrier at Southeast entrance.
Fig. 2 Partial barriers can easily be bypassed as at
the Irvington Place entrance.
5

7. Section 2. Road Removal Plan for Robles Pass
2.a Introduction
The proposed methods for habitat remediation at Robles pass are an adaptation of the
techniques and study results found in the existing literature. Much of the techniques are
still in the experimental stages and each area is unique. Much of the literature concerns
more forested terrains and roads that have been built on contour. The situation at Robles
Pass presents many challenges.
o The roads are steep and many are severely eroded.
o There is limited access for large machinery, without building more roads.
o Hauling material will be time consuming.
o There is an extensive network of roads in the preserve.
o Continued access by illegal off road vehicles.
2.b Plan Outline
1. Site Inventory and analysis
o Roads
o View Sheds
o Existing Vegetation
2. Chose priorities.
3. Chose equipment
4. Stockpile material
5. Recontour and restructure road
6. Construct water control and water retention structures
7. Revegetate.
8. Irrigate to establish plants.
9. Regular Inspection
10. Evaluation over time
12. Ongoing documentation
2.c General Site Analysis Guidelines
Begin by visually inspecting the area, using aerial photographs and topographic maps as
aids and for documentation. Record data using photographs and field notes.
o Roads
 Slope: Can machinery safely access the site, or is hand work necessary?
 Degree of erosion: Is there enough material on site or does soil need to
brought in? What are the extents of rutting and channeling?
 Surface texture: Is there exposed bedrock, loose soil and gravel? How will
this affect ripping and digging?
6

8. Access points: How accessible is the road for construction and where are
the most effective closure points?
 Recontouring: Is recontouring needed and will it cause more destruction of
habitat?
o View Sheds
 Access the site from various locations and distances, within and without
the boundaries of the site. What are the projected perspectives of user
groups? What is visible from the surrounding neighborhoods?
o Vegetation
 Take an inventory of the existing vegetation.
 Record vegetation changes along the length of the road. Do the changes
correspond to slope, surface material, soil texture, exposure, elevation?
 Note predominant tree and shrub species. What are the average spacing
and ratios between individual plants and different species?
 Smaller annual and perennial herbs and grasses for custom seed mix.
 Patterns of dead or dying shrubs and trees. (This information can be used
for initial camouflage and habitat remediation).

2.d Robles Pass Site Analysis
Roads
Robles Pass Preserve has an extensive network of wildcat roads due to historic illegal off
road vehicle use and some mining.
The roads show varying degrees of erosion, fr om several inches of topsoil loss to gully
formation. Only the m ining road was built fo llowing the contour. The other roads run
straight up and down hillsides and ridges, or in washes.
There are signs of continued use by ORV’s.
Fig.3 There is extensive erosion on many of the
roads in the preserve.
Fig.4 Habitat loss and dumping.. Tire treads are
visible.
7

9. Fig.5 This photo, taken from the south side of the
park shows the extensive nature of the wildcat roads.
Fig.6 Gully formation
View Sheds
There are many attractive views at Robles Pass, from inside and into the preserve.
From many of the interior areas there are no visible signs of the surrounding city.
The many road scars are visible form many locations inside thus detracting from the
natural experience that is the goal of the preserve. Some road scars are visible from the
surrounding neighborhoods and roads.
Fig.7 Sunrise at Robles Pass
Fig. 8 Road scars have a negative impact on the
scenic beauty of the site.
8

10. Vegetation
There are two predominant tree species at Robles Pass, foothills palo verde (Parkinsonia
microphylla) and white thorn acacia (Acacia constricta) along with several cactus
species, Prickly pear (Opuntia engelmanii), the Saguaro (Carnegiea giganta), and
various cholla species (Opuntia spp.). These species are found throughout the preserve.
Other trees and shrubs that are found in many locations are Ocotillo (Fouquieria
splendens), creosote (Larrea tridentata), velvet mesquite (Prosopis pubescens), jojoba
(Simondsia chinensis), wolfberry, (lyceum sp.), and fairy duster (Caliandra eroiphylla),
Brittle bush (Encelia farinosa) and triangle leaf bursage (Ambrosia deltoids) are every
common. There are many small annuals, perennials, and grasses that would provide the
seed bank for long term stability of the system.
(Note: Identification of annuals and grasses is not complete)
Figs. 9-12, below, show the varied vegetation found at different locations in the preserve.
It is significant for developing a planting plan that will reflect local conditions.
Fig.9
Fig.10
Fig.11
Fig.12
9

11. Section 3. Road Removal Procedure
At the Robles Pass Preserve we have prioritized the roads to be removed. Each road in
the preserve has its own set of problems and solutions, and the details of each plan, while
following the basic guidelines, are modified to reflect each individual case. The plan is
developed as a synthesis of the goals for removal, the guidelines in Section 1, Road
Removal Strategies, and the site analysis. The decision for the first road (to be referred to
as Project Road A) was based on the high visibility of the road scar and its central
location.
Current condition of the Road
The Project Road is approximately 1300 ft. in length and averages 8 to 10 ft wide. There
is no extensive erosion, or loss of soil. For the most part the road surface is at the same
level as the surrounding desert. The edges are lined with built up rock that was pushed
aside by the off road traffic. There is some gully formation in the center section and the
lower section needs some recontouring.
The Plan
For purposes of phasing, The Project Road A was divided into three sections along its
length. The upper section of exposed bedrock, the middle section, with a surface of sand,
gravel, and some rock, and the lower section with a network of several entry roads that
converge at about 120 ft up the slope. The work will be done with a Sweco Trail Dozer.
This four foot wide dozer will have minimum impact and will be able to access the site
and maneuver the narrow, steep roads. Along with a small trailer the plant material and
water can be hauled in.
The documentation of the project will be ongoing, recorded with photos and notes.
Phase 1
o Signage will be displayed prominently at the base of the road, indicating that a
revegetaion program is under way. Temporary structures will be erected, so as to
leave one five foot wide access for the Sweco. Posts with a chain can be put at
this entrance.
o The entry will be planted with Parkinsonia microphylla, Acacia constricta,
Opuntia engelmanii.
o The two gullies in the central section will be filled in and diversion drains will be
dug above the head of each gully. Vegetation will help to stabilize the fill.
Phase II
o The upper section of bedrock is to be revegetated.
o Approximately 25 holes for planting will be dug by hand where feasible in and
around the rock slopes. These trees will be irrigated by a small pump and by hand,
when close enough, from a water trailer or small tank brought in with the sweco.
Phase III
o From this point on the work will proceed from top to bottom, filling in the central
section.
10

12. The trails being constructed in the preserve will cross the road at two points.
These will provide a good supply of plant material for planting especially prickly
pear and cholla. The trimmed branches and limbs from the trail building will be
used for vertical and horizontal mulch. Soil from tread building will also be
utilized. These materials usually are scattered in the desert, a time consuming
process. Both projects will benefit from this proximity.
o As access will be closed off as the project progresses, it will be most efficient to
work in sections so that the plant materials and water can be brought in on a
trailer close to the planting area. Plants will be brought in at approximately 20 at
a time so they can be trailered in as close to the planting area as possible, and
planted in a timely manner. This will also facilitate initial irrigation as the
watering can be done as the work progresses, minimizing the need to walk up and
down the hill.
o Planting holes will be dug at approximately 10 foot spacing for the Parkinsonias
and Acacias, and smaller holes will be filled in between them, for Opuntias and
other small shrubs.
o A combination of drainage ditches, swales and berms, water catchments, pits, log
and rock lines will be installed along with the holes as access allows.
o
Phase IV
o The access area at the base of the road will be closed off and the planting will be
completed.
o The signs and temporary barriers will stay in place until the trees have become
established.
o A small water trailer will be brought in and water pump set up, preferably solar
operated, as a supplement to rain water to help the plants become established
more quickly.
Post Completion Evaluation
o Monitoring will be done on a continuing basis to evaluate the results of the road
closing project.
.
Fig. 13 Robles Pass preserve.
Location of Project Road A is shown in center
Fig. 14 View of road scar from the east. The
visible portion is the upper two thirds.
11

13. Fig. 15 Close up of the Project Road A.
12

14. Bagley, Scott. Desert Road Removal: Creative Restoration Techniques
Road-RIPorter, July/August 1999, Volume 4 #4
http://www.wildlandscpr.org/biblio-notes/desert-road-removal-creative-restorationtechniques
Bainbridge, David A. A Guide for Desert and Dryland Restoration
Bainbridge, D.A. and R.A. Virginia. 1990. Restoration in the Sonoran Desert of
California. Restoration and Management Notes 8(1): 3-14.
Bainbridge, D.A., M. Fidelibus, and R. MacAller. 1995. Techniques for plant
establishment in arid ecosystems. Restoration and Management Notes 13(2): 190-197.
Bloom, A.L. 1998. An assessment of road removal and erosion control treatment
effectiveness: a comparison of 1997 storm erosion response between treated and
untreated roads in Redwood Creek Basin, northwestern California. M.S. thesis. Arcata,
CA: Humboldt State University.
Cotts, N.R., E.F. Redente, and R. Schiller. 1991. Restoration methods for abandoned
roads at lower elevations in Grand Teton National Park, Wyoming. Arid Soils Research
and Rehabilitation 5: 235-249.
HÄLBICH, T.F.J. Mine rehabilitation in the arid Succulent Karoo vegetation zone on the
South African west coast, Namakwa Sands—case study. Heavy
Minerals 2003, Johannesburg, South African Institute of Mining and Metallurgy, 2003
Luce, C.H. 1997. Effectiveness of road ripping in restoring infiltration capacity of forest
roads. Restoration Ecology 5(3): 265-275
Merrill, Brian R.,Casaday, E. 2001. Field Techniques for Forest and Rang Road
Removal. California State Parks, North Coast Redwoods District, Roads, Trails, and
Resources Maintenance, Jan. 2001
http://www.parks.ca.gov/pages/23071/files/field%20techniques%20for%20road%20remo
val%20part%201.pdf
VanderMeer, Mark. Blowing Smoke and Throwing Seeds: A Road Ripper’s Guide to
Spotting Pathetic Revegetation Plans Road-RIPorter. May/June 1998, Volume 3 #3
Zeedik, B. Jansens, J-W. Introduction to Erosion Control.. Joint Publication of, Earth
Works Institute, Quivira Foundation, Zeedyk Ecological Consulting. March, 2006
13