Acorn Trail Realignment

The trails in Arastradero Preserve receive heavy use from all visitors during every season. Due to the heavy clay soils and drainage patterns, many of the trails are especially vulnerable to damage and require frequent maintenance. Typical problems include ponding and ruts due to lack of proper drainage, berms on the outside of trails and lack of tread definition. The Acorn Trail is no exception, with soil problems compounded by poor layout.

     Trail Center volunteers rerouted several hundred feet of the Perimeter Trail in 1998, closed a volunteer trail and repaired erosion damage. In 1999, we repaired 600 ft. of the Perimeter Trail between Portola Stables and Gate B. [See the description and schedule for the project]

     An aerial photo [158KB] of the project, including trail names and project features is available. The City of Palo Alto's site includes a map of the preserve. You may also wish to see a MapQuest map of the Preserve and surrounding area.

Acorn Trail (March 11, Apr. 22, May 13 and June 3): We will realign the southeast section of the Acorn Trail between Meadowlark and Corte Madera Trails. The existing trail is a moderately steep section vulnerable to erosion and largely impassable during the wet season, particularly at the bottom. The grade on the upper half is 12-13%; on the lower half, 13-17%. The reroute will move this segment to the south; the junction with Meadowlark Trail will be shifted slightly uphill of its present location, while the junction with Corte Madera Trail will be shifted approximately 300 yards south. The new alignment will create one of the Preserve's few wooded trails.

Detailed Description: The new alignment begins at the Meadowlark Trail, ten to fifteen feet south of the existing crossing (on the south side of the old fence line); a small adjustment to the Acorn Trail on the other side of Meadowlark would be necessary. The trail curves through meadow into the drainage, crossing approximately 30 feet above a gullied section of the drainage (erosion control may be an adjunct project). It then curves to the southeast, crosses the ridge approximately fifty feet uphill of the fence line, then drops down across the meadow between the fence line and the drainage to the southeast. At the drainage, the trail crosses above a large area of poison oak and continues to drop down the south side of the drainage. Upon reaching a sharp elevation break at the edge of the low ridge, the trail turns southwest and drops until meeting Corte Madera Trail twenty feet uphill of the edge of the oak woods and approximately 300 ft. southwest of the existing junction.

     Following completion of the reroute, the old trail will be closed and restored to natural conditions.

Trail Width: 3.5-4 ft.

Maximum Grade: 10% for new construction; existing grade for maintenance

Outslope: 2-3% (standard)

Flagging: At grade level (consult crew leader)

Hazards and Other Considerations: poison oak, wasps (possible), ticks. The new alignment crosses a stand of purple needlegrass (Nisella pulchra), which will be removed from the trail route for replanting elsewhere on the preserve

Total Distance: Approx. 1400 ft.

Structures required: 1-2 culverts

Expected Number of Workdays: 2

Access to Worksite and Parking: Parking at Preserve main lot, along Alpine Rd. near Page Mill intersection, Page Mill Park & Ride

Water, Restrooms, Picnic Area: Water and restrooms at main lot (or as arranged); picnic area to be announced at workday

Emergency: 911 from phone at main lot or by cell phone

Nearest Hospital: Stanford Hospital. From Alpine Rd., go to Page Mill Rd., turn left and go to I-280 entrance. Take I-280 2 mi. north to Alpine Rd. exit; go right on Alpine and travel 2 mi. to Sand Hill Rd. Turn right and travel 1.5 mi. Stanford Hospital entrance and follow signs to Emergency.



     
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