TO: City of Boulder Open Space Board of Trustees

FROM: Boulder Area Trails Coalition Board of Directors

DATE: September 28, 1998

SUBJECT: Dry Creek Trail Alignment, South Boulder Creek Management Plan

REFERENCES:

As a result of the field trip and our discussions with the staff, we have been able to better characterize a Dry Creek trail alignment south of the Baseline reservoir that we believe minimizes user impacts to the area while providing appropriate, additional access to provide some compensation for that being proposed for removal elsewhere in the management area. The proposed alignment would also serve as the western segment of a trail connecting the South Boulder Creek and Teller Farm trail systems as envisioned in the Boulder County Comprehensive Plan. As we discussed in our previous letter (Reference 1), we believe this trail alignment provides an important regional trail connection and adds an essential element of balance between recreation and preservation to the management plan.

Attached is a rough map of the proposed trail alignment. In general, the alignment follows the path we walked on Friday (with some significant modifications in the middle section to avoid potential raptor perches in the cottonwoods near Baseline reservoir). The trail would begin at the existing Dry Creek trailhead and would run west along the alignment proposed by the Open Space staff through the first (or front) field and cross the irrigation ditch at the existing bridge into the second (or back) field. The trail would then turn southwest and parallel the irrigation ditch on the east boundary of the Open Space property. When the irrigation ditch turns sharply to the west the trail would cross the ditch on a new bridge and then parallel the ditch on its south side for about three tenths of a mile. The trail would continue to follow the irrigation ditch as it turns southwest. After a tenth of a mile the trail would turn south along the eastern side of an existing interior fence line until it reaches an old farm road. The trail would follow the farm road south, crossing over an existing bridge, until South Boulder Road is reached. The trail would then turn west and parallel South Boulder Road on the north side of the large existing dirt berm until the intersection of South Boulder Road and Cherryvale Road is reached. Here the trail would join the existing Open Space trail connecting to the Cherryvale trailhead and to the South Boulder Creek trail. The total length of the proposed additional trail alignment is 1.3 miles (plus 0.5 miles which is shared with the Dry Creek trail recommended in the management plan). A rough estimate of the construction cost for the new trail section is $37,500 ($5/foot for 6 foot crusher fines trail surface and $10,000 for the ditch crossing).

This trail alignment utilizes existing, available Open Space lands south of Baseline Reservoir. It avoids the wetlands, prairie dog Habitat Conservation Areas, Preble’s meadow jumping mouse, Spiranthes diluvialis, and Ute ladies’-tresses habitats, and is out of sight or sound of adjacent private homes. It can be separated from the Habitat Conservation Areas and potential raptor perches by physical boundaries (existing or new fences and the irrigation ditch). It is sited to avoid close proximity to or visibility from the clusters of cottonwood trees along the southeast edge of the Baseline reservoir that have been used for raptor perches.

Although the 1/4 mile (400 meter) radius exclusion zone from the raptor perch sites recommended by the Open Space staff cannot be maintained (the Open Space corridor itself is less than 1/4 mile wide in some areas), we believe this requirement is unnecessarily restrictive (see Reference 2 for this and the following discussion). The alignment maintains a buffer of from 250 to 400 meters from the northern cluster of cottonwoods and is visually and physically shielded from the southern cluster. The staff’s recommendation is based on buffer zone suggestions for nesting raptors and we are dealing in this case primarily with perches, not nest sites. The only nesting raptors are a pair of Swainson’s hawks in the northern cluster of cottonwoods. This nest has been successful despite extensive human activity in close proximity (dog walking in the back field and motor boats and picnic tables on the immediately adjacent reservoir property). However, we support the staff’s recommendation to provide an additional buffer for this area (the staff’s recommendations and the proposed trail alignment provide buffers from 250 to 400 meters). We believe this significantly enlarged buffer area provides reasonable and adequate protection for the nest from Open Space properties. With the suggested alignments, the southern perch site will have an 800 meter buffer to the north and will be visually and audibly shielded from human disturbances to the east and south by the irrigation ditch and its raised northern bank and associated trees. The staff’s own research indicates that such shielding is an appropriate alternative to large buffer distances ("Nonthreatening activities, such as those occurring on recreational trails, may be compatible with a nest or perch location in close proximity if that activity is visually or audibly buffered by vegetation or topography.", Reference 2, p. 635). We encourage the staff to work with the various parties that have an interest in Baseline reservoir to minimize human disturbances to the northern and the southern perch sites from recreational uses of the adjacent reservoir lands.

We believe this trail alignment is the best of the various alternatives that have been proposed. It avoids the private property, poor quality user experiences, and safety issues of the other alternatives. It preserves and protects the environmental values of the Dry Creek area while providing our Open Space users an opportunity to appreciate and enjoy those values. We believe it will provide a high quality recreational experience that can be realized in an environmentally sensitive manner.

Therefore, we request that the Open Space Board of Trustees direct the staff to actively pursue this trail alignment along the south side of Baseline reservoir.