Soil Ecology and Research Group last update October 28, 2000

Murphy Canyon Riparian Restoration on Marine Corps Air Station Miramar, San Diego, California: First Annual Report

Introduction
Marine Corps Air Station Miramar (MCAS), hereinafter referred to as the "Station", is located on 23,116 acres of land in San Diego County, California four miles east of the Pacific Ocean and thirteen miles north of downtown San Diego. Construction projects associated with the realignment of NAS Miramar filled 0.14107 acres of vernal marsh, 0.008814 acres of coastal and valley freshwater marsh and 0.06562 acres of disturbed riparian forest for a total of 0.29483 acres of wetlands. The Department of the Navy, in accordance with the Department of the Army permit (95-20158-ES) on the Realignment of Naval Air Station Miramar to Marine Corps Air Station Miramar, is required to mitigate impacts to non-vernal pool wetlands at a 2:1 replacement ratio by restoring or creating riparian habitat. The Department of the Navy signed a Cooperative Letter of Agreement with the Soil Ecology and Restoration Group (SERG) at United States International University (USIU) in June 1999 to restore a 1.03 acre area of riparian habitat on the eastern section of the Station. During the first year, a channel was graded and the site was planted with both seedlings and cuttings of riparian and coastal sage scrub species. Monitoring of flora and fauna on the site will continue through June 2004. Data collected from this project will aid in future riparian restoration projects on Miramar and similar habitats. In addition, the success of this project will result in a surplus of 0.43 acres of wetlands restoration over the required 0.6 acres for mitigation. This surplus may be available as banked mitigation for future project needs.

Study Site
The 1.03 acre, flat site is located in Murphy Canyon along the eastern edge of a river bed (Figure 1). The site is bordered to the east by a dirt road and to the north and south by riparian habitat. Vegetation on the site in August 1999 was primarily exotic species such as slender wild oat (Avena barbata), tocalote (Centaurea melitensis), filaree (Erodium sp.) and fennel (Foeniculum vulgare). Native vegetation on the site and surrounding area in August 1999 consisted of arroyo willow (Salix lasiolepis), poison oak (Toxicodendron diversilobum), fuchsia-flowered gooseberry (Ribes speciosum), laurel sumac (Malosma laurina), flat-top buckwheat (Eriogonum fasciculatum) and mule fat (Baccharis salicifolia). The east and west edges of the canyon are sloped approximately 45 degrees and covered with coastal sage scrub

Figure 1. Location of riparian restoration site on Marine Corps Air Station Miramar.

and chaparral. Access to the site is via a dirt road from the former Camp Elliot area of the Station. Possible cause of disturbance, found by reviewing historical aerial photographs, USGS maps and the history of the area, is most likely Camp Elliot activity, although creation of the dirt road may have added to the impact. The reference site for this project is located approximately 2.7 kilometers northeast of the restoration site in the former Camp Elliot area of the Station. The reference site is riparian woodlands bordered to the south by "H" Avenue. Vegetation on the reference site is dominated by California sycamore (Platanus racemosa) and Arroyo willow (Salix laevigata).

Site Preparation
Site preparation began by clearing exotic vegetation on the site using a John Deere 450 bulldozer with an eight foot wide blade and tilling it into the soil. A channel approximately 3 meters (m) wide,1 m deep and 165 m long through the center of the site running parallel to the dirt road was constructed using the bulldozer in January 2000 (Figure 2). The channel connects to the riverbed on the north and south end of the site.

Two below ground water monitoring wells were installed in March 2000; one on the east side of the channel and one on the west side (closest to the riverbed). Wells were created from 1.52 m lengths of PVC pipe, with slits cut into the pipe to allow water flow (Figure 3). The slits were covered with screens to prevent sediment from leaking into the wells. Holes for the wells were dug using a power auger and by hand using shovels and a 15 pound digging bar. The pipes were placed 1 meter into the ground. The holes were filled back in around the pipe with rocks from the site and commercial grade sand and sealed at the top with Bentonite.

Container Plant Propagation
Two hundred and twenty-one container plants from both seeds and cuttings were grown in the greenhouse at San Diego State University and the shadehouse at USIU between July 1999 and January 2000. This was less than the 245 species originally proposed as not all seedlings were ready for planting. All propagation material was collected on the eastern section of the Station. Cuttings were 15 to 20 cm in length cut at an angle at the bottom and straight on the top end. First placed in sand flats until roots sprouted, the cuttings were then transplanted to a

Figure 2. Grading of channel through restoration site.

Figure 3. PVC Pipe used for monitoring well (Red end into ground).

container with a 1:1:1 (super soil: perlite: sand) standard potting mix. Seedlings were watered three times per week and fertilized once each month. Water and fertilizer were reduced two months prior to planting and plants were removed from under shade cloth at least four months prior to planting.

Planting
A total of 221 container seedlings were planted January through March 2000 (Table 1).. Planting areas were separated into three planting zones ( Heffernan 1999). Coastal sage scrub species were planted in zone 1 (adjacent to the dirt access road), willow and mule fat in zone 2 (adjacent to riverbed and channel) and cottonwood, sycamore and elderberry in zone 3 (clusters or patches). Holes for seedlings were dug at least 1.5 m apart using either a shovel or power auger. Plant protection in the form of Treepees, cone shaped plastic coverings one to two feet tall with a one foot wide base, or tubex were placed over each seedling to reduce herbivory (Figure 4).

One hundred and ten additional cuttings of Arroyo willow, Mule fat and California sycamore were cut and placed directly into the ground in February and March 2000. These cuttings were approximately 35 centimeters (cm) long and placed approximately 25 cm deep into the ground.

Table 1. Container plant species planted on restoration site in Spring 2000.

Figure 4. Restoration site after completion of planting in March 2000.

Maintenance
Supplemental irrigation was provided to the seedlings twice each month May through June 2000 via a 180 gallon water tank in the bed of the SERG four wheel drive (4WD) pickup truck. Water was supplied to the site, gravity fed, through a ¾" garden hose and 3 gallon watering cans. Each seedling received approximately ¾ gallon per watering.

Treepees and Tubex will be removed from around each seedling as it outgrows the protection device.

Exotic vegetation was not sprayed on the site due to a six week delay in receiving permission from the Navy to use herbicide. Exotic grasses on the site were cut down using a weed trimmer. A Pest Management Plan and Purchase Approval Request Form 12ND WESTDIV 6250/14 will be submitted with the 2001 annual report as herbicide was not used this year.

Monitoring
Water levels on the site were measured in the wells in March 2000 and June 2000. Vegetation percent cover, density and ground substrate were monitored on 22 June 2000 using a modified California Native Plant Society (CNPS) method (Sawyer and Keeler-Wolfe, 1995). Perennial shrub vegetation on the site was analyzed using four 25 meter (m) transects, with measurements taken every 0.5 meters for a total of 50 points per transect. Three of the transects were established perpendicular to the riverbed and the road and one transect parallel to the road in the coastal sage scrub zone. Transects positions were selected to avoid existing native vegetation on the site. Plant density for each species of perennial shrubs was measured by counting numbers of plants within 2.5 m on each side of the transect for a total area of 125 m2 for all three transects in the riparian area. The transect in the coastal sage scrub area parallel to the road was narrowed to 1 m on each side (50 m2 total area) due to the close proximity of the dirt road. The zero meter point of each transect was marked with a 1 m wooden stake painted red for future surveys. Percent survival of container seedlings was determined by assigning each plant a rating of 0 (dead), 0.5 (alive, but unhealthy), or 1 (alive and healthy). Installation of the project and progress was photographed using 35 mm film from selected photo points.

Five soil samples, 10-12 centimeter (cm) deep, were collected on both the site and in the undisturbed riparian area on the station in June 2000. Soil samples are being analyzed for available nitrogen (ammonium and nitrate), available phosphorus, pH and organic matter by A & L Laboratories.

Birds, reptiles and small mammals were monitored in August 1999 before site preparation began. Relative materials, methods and results may be found in the restoration plan for this site (Heffernan 1999). Flora and fauna surveys will be conducted next in May 2001.

Results
Ground water in the wells was found at 3.7 feet on the east side of the channel and 2.5 feet on the west side of the channel in March 2000. There was no measurable water in the wells in June 2000, however, moisture was still present in the form of condensation indicating moist soil. In addition, water flowed through the artificial channel on the site on two occasions during precipitation events in March 2000. Water levels in the channel reached up to 25 cm as evidenced by moist soil on the sides of the channel.

Overall percent seedling survival on the site in May 2000 was 76 percent, below the required 98 percent (Table 2).

Overall percent cover in June 2000 was 4 percent, below the required 10 percent (Table 3). However, the density was 388 seedlings per acre, well over the 300 plants per acre success criteria.

Table 2. Container plant survival on restoration site in May 2000.

Results of soil analysis will be included in next year's annual report as soil analysis by A&L Laboratory was not complete at the time of this report.

Table 3. Results of annual vegetation survey in June 2000.

Discussion
The presence of water in the artificial channel demonstrates successful creation of the channel. This water will aid in the future success of the restoration site by extending the area of the site exposed to water.

Percent survival was low at 76 percent due to the ranking system used. Most of the seedlings grew after planting, but died back in May. The seedlings that were alive, but unhealthy were counted at 50 percent. These seedlings are being kept alive through the summer with supplemental watering until next winter when their roots grow deep enough to tap into the water table. As these seedlings improve in health over the next growing season, the survival rate should notable increase.

Percent cover was also low as seedlings stopped growing in May. However, plant density at 388 plants per acre was higher than expected and should lead to increased percent cover next year. Exotic vegetation cover was high at 38.4 percent due to the delay in receiving approval to use pesticides. Dried exotic vegetation was cut down, but the seed already matured and fallen on the ground.

Conclusions and Recommendations
Water levels in the wells will continue to be monitored in March, June, September and January each year. In addition, water flow through the channel will be monitored during the winter months.

To ensure native plant percent cover reaches success criteria, additional cuttings from Arroyo willows, Black willows and Cottonwoods will be installed on the restoration site in the January 2001. Permission to spray exotic vegetation on the site has been granted through the year 2004. To compensate for the growth and germination of weed seed such as Mustard and exotic grasses during spring 2000, the site will be sprayed with herbicide two times during spring 2001. This should allow a diversity of exotic vegetation to germinate and be sprayed before producing seed. Exotic vegetation on the site will continue to be sprayed through the year 2004.

Data collected on small mammals, birds and reptiles on the site in August 1999 will serve as a baseline for surveys to be conducted in May 2001 through 2004.

References
Heffernan, Lisa. Murphy Canyon Riparian Restoration on Marine Corps Air Station Miramar, San Diego, California. October 1999. Soil Ecology and Restoration Group. United States International University.

Second Annual Report (December 17, 2001)

Third Annual Report (February 17, 2003)