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

Table of Contents

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

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Section 1. Road Removal Strategies

1.a Why Remove Roads? Roads may have negative impacts in several areas:

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.

o Ecological (Wisdom, 2000). Direct loss of Habitat Habitat fragmentation Increased human impact, as a result of improved access.

o 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 Closure o Decommissioning o 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.

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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.

o 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

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Adds organic material. Horizontal mulch: branches and limbs laid across the road.

o 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).

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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.

t

the Irvington Place entrance.

Fig. 2 Partial barriers can easily be bypassed as a

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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?

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 Fig.4 Habitat loss and dumping.. Tire treads are roads in the preserve. visible.

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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. 8 Road scars have a negative impact on the Fig.7 Sunrise at Robles Pass scenic beauty of the site.

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Vegetation o predominant tree species at Robles Pass, foothills palo verde (Parkinsonia

rve.

joba

t complete)

igs. 9-12, below, show the varied vegetation found at different locations in the preserve.

There are twmicrophylla) 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 preseOther trees and shrubs that are found in many locations are Ocotillo (Fouquieria splendens), creosote (Larrea tridentata), velvet mesquite (Prosopis pubescens), jo(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 theseed bank for long term stability of the system. (Note: Identification of annuals and grasses is no FIt is significant for developing a planting plan that will reflect local conditions.

Fig.9 ig.10

Fig.11 Fig.12

F

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Section 3. Road Removal Procedure

t the Robles Pass e

to

ondition of the Road ly 1300 ft. in length and averages 8 to 10 ft wide. There

he Plan of phasing, The Project Road A was divided into three sections along its

d,

gnage will be displayed prominently at the base of the road, indicating that a to

e upper section of bedrock is to be revegetated. hand where feasible in and

d,

this point on the work will proceed from top to bottom, filling in the central

A 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, whilfollowing 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 as Project Road A) was based on the high visibility of the road scar and its central location.

urrent cC The Project Road is approximateis 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. TFor purposeslength. The upper section of exposed bedrock, the middle section, with a surface of sangravel, 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.

hase 1 Po Si

revegetaion program is under way. Temporary structures will be erected, so as 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.

ase II Pho Tho Approximately 25 holes for planting will be dug by

around the rock slopes. These trees will be irrigated by a small pump and by hanwhen close enough, from a water trailer or small tank brought in with the sweco.

hase III P

o Fromsection.

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o 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

be

o be brought in on a

and

d smaller holes will be filled in between them, for Opuntias and

installed along with the holes as access allows.

o The access area at the base of the road will be closed off and the planting will be leted.

supplement to rain water to help the plants become established

ation o Monitoring will be done on a continuing basis to evaluate the results of the road

pear and cholla. The trimmed branches and limbs from the trail building will 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 twork in sections so that the plant materials and water cantrailer close to the planting area. Plants will be brought in at approximately 20 ata time so they can be trailered in as close to the planting area as possible, andplanted 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 down the hill.

o Planting holes will be dug at approximately 10 foot spacing for the Parkinsonias and Acacias, another small shrubs.

o A combination of drainage ditches, swales and berms, water catchments, pits, logand rock lines will be

Phase IV

compo 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 amore quickly.

Post Completion Evalu

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.

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Fig. 15 Close up of the Project Road A.

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