FOBOS comments on Eldorado Mtn/Doudy Draw Trails

Submitted July 27, 2007. (All GPS coordinates (N latitude/W longitude) reported in WGS84)

The Visitor Master Plan provided for the creation of “Natural Areas” and established as two of the goals for such areas:

  1. “Accommodate low-impact visitor activities where adequate trails exist or can be built, and resource impacts can be minimized.”
  2. “Protect the quality of natural…resources (especially where high-value resources exist).”

Thus, new trails in designated Natural Areas should be designed and constructed in a manner that minimizes their impact on the area’s natural values.

The proposed trails will introduce intensive recreation (mountain biking), along with hikers, dogs, and equestrians into a biologically rich part of Boulder City open space in which no designated trails currently exist. As an area of relatively high-elevation grasslands and forests, with extraordinarily important ecotones, along with densely vegetated drainages, the Eldorado Mountain-Doudy Draw (EMDD) Natural Area supports substantial populations of bear, elk, wild turkey, deer, small mammals and as many as 30 breeding bird species, and it constitutes recognized hunting grounds for mountain lions. Because much of the Natural Area has been without trails and off limits to dogs, wildlife populations thrive in this Natural Area, as do important native plant communities. The OSMP Inventory Report (2/24/06) points out that:

  • the xeric tallgrass communities in this and adjacent areas are unmatched in our region in terms of size, quality, and composition. “Noxious weed species pose a major threat.” (p.18);
  • the shrublands “support the highest breeding bird densities of any OSMP ecosystems…and provide habitat for bears, deer, mountain lion, and small mammals…that utilize them for food, cover, and movement across the landscape.” This area holds part of the second largest deciduous shrubland in the OSMP system, and these shrublands are “a relatively rare habitat type” along the northern Front Range and on the OSMP system and “a rare and threatened community statewide” (p.19);
  • the riparian communities “provide habitat for many animals, including bears, mountain lions, songbirds, raptors, deer, elk, small mammals, herptiles” and “undeveloped riparian corridors are becoming increasingly scarce along the Front Range and particularly in the Denver-Boulder metropolitan area” and are threatened by “infestations by non-native species” (p.20);
  • mature Ponderosa forests, another “rare habitat type along the Northern Front Range and in the OSMP system,” see regular use by Abert’s squirrels, bobcats, mountain lions, wild turkey, bear, and a wide variety of bird species (p. 21);
  • Needle and Thread grassland communities, on the rocky mesas, are another “rare and threatened community statewide.” Dalmatian toadflax and other high priority noxious weeds (like jointed goatgrass and sulfur cinquefoil) “pose a significant potential threat.” (p. 22);
  • additional invasive species (e.g., chicory, diffuse knapweed, cheatgrass, myrtle and leafy spurge) are also called out as threats because they spread along recreational trails and threaten the quality of adjacent native plant communities and wildlife in this area (p.26);
  • recreational activity along trails, especially when accompanied by dogs, displaces and decreases reproductive success of wildlife species that depend on this habitat (p.30-31);
  • species that seem to have thrived in this area, like the elk and wild turkey, “require grasslands and forests in juxtaposition, are known to only a few areas on OSMP lands, and are shy to human presence” (p.31 &33).

For these reasons, quantification of pre-trail occurrence and use of the area by these species is essential if we are to be able to assess the trails’ impacts on the natural resources and make wise management decisions as promised in the VMP (VMP p. 62-63).

It should be noted again that this Natural Area was originally and appropriately designated as a Habitat Conservation Area because of its extraordinary natural values—critical habitats and large habitat blocks not penetrated by trails. FOBOS regrets that political decisions have intervened to downgrade the area to “Natural Area”, thereby opening the door to inappropriate intensive recreation and a rapid proliferation of visitors without adequate prior study to provide a baseline for comparison with the inevitable and deleterious impacts to the natural resources that will come with the increased use, the variety of ecosystems that will be fragmented, and the native species that will be affected.

The challenge for the community and the City is to provide for reasonable and well managed visitor access while allowing the native flora and fauna to sustain themselves and to protect the area’s priceless natural values. Alignment decisions should be based on selecting alternatives that achieve some reasonable degree of resource conservation. We present here several alternatives that have not yet been considered and that would lessen ecological damage compared to options presented by the OSMP documents dated July 3, 2007 while still providing a good visitor experience.

FOBOS regrets OSMP’s plan to build trails before staff has established baseline information with respect to the existing condition of the habitat and the resident plant and animal communities, as promised in the Dec.8, 2006 TSA Plan. We strongly urge OSMP to follow that Plan and sound land-management practices and, prior to trail building, to establish monitoring programs that will develop this information and will describe remedial management actions that will be utilized should impacts exceed levels defined as acceptable. We also recommend that this monitoring be used to track impacts of the increased visitation associated with the trails and that management actions be taken, as needed, based on the definitions of acceptability.


  • Do not construct a trail in Spring Brook Meadow. Several alternative routes for Trail 13 and connecting stems are described below.
  • Delay construction of trails in the northern section (the 13s–upper, lower, stem). These trails are deeply flawed, as described below. More time is needed to determine their impacts and to consider alternative routes, some of which are proposed below.
  • Minimize placement of trails along the forest/grassland ecotones. These areas are well documented as uniquely important habitat for many animal species. The proposed trail alignments for both 13 and 14 tend to follow the ecotones for much of their length.
  • Consider a modified version of upper 14. Both upper and lower 14 would cut through an important and highly valuable forest/grassland ecotone as well as interior forest and consequently are highly disturbing. Upper 14 appears to have fewer deficiencies, and we recommend a modified version of it (described below) over any version of lower 14.
  • Avoid trail placement along side slopes with unstable soils. The proposed alignments include substantial segments that would traverse hillsides with considerable slope and with highly fragile soil types. There are significant construction issues as well as user safety issues associated with such segments.
  • Begin monitoring immediately. Our preference is that construction of a modified version of upper 14 proceed after sufficient monitoring is completed, and be connected to Doudy Draw with an alternate alignment that we propose. See Alternative route for Stem Trail proposed below. The use of Trail 14 would be observed for a sufficient length of time to assess its effects on wildlife, trail sustainability, and compliance. Such observations should inform decisions about the possibility of other trails in the subarea.

FOBOS again requests a monitoring plan that

  • will provide critical baseline information on the alignments of any possible trails, and
  • will be carried out for at least one year before construction begins.

FOBOS requests that, before trails are built, the OSMP Department provide detailed documentation about procedures for monitoring user impacts and how/when impacts would be used to trigger management decisions, including temporary or permanent trail closure, based on the definitions of acceptability (see VMP p. 62-63). The public should be involved in the formulation of these definitions, as promised in the TSA Plan.

  • Minimize trails in riparian areas. Very few generally undisturbed riparian areas remain in OSMP lands and the negative impacts of trails in riparian areas are well documented. Consequently all routes that must cross riparian drainages should be routed perpendicular to the drainage and, where desirable, include a bridge that directs visitor travel and prevents riparian access.
  • Given the extent of invasive weed cover in Doudy Draw, weed control must occur prior to any Doudy Draw Re-Route and prior to the start of trail building up “Trail 13 – Stem” or our “Alternative route for Stem Trail” and on through this area. The potential for weed invasion – both during construction and through visitor use – also underscores the need for pre-construction monitoring so that the kind of measures promised in the VMP (e.g., see p. 63) and TSA Plan can be fulfilled.

FOBOS’s current understanding of the initial controlled experiments on jointed goatgrass at the mouth/lowest segment of Doudy Draw is that full scale control application of the tested herbicide could begin this fall. OSMP would then have information on whether these efforts were successful in spring of 2008, well before any construction should begin on the reroute of the Doudy Draw Trail. If our understanding is correct, these results would provide reasonable data on control of at least one of the invasives that are particularly problematic in the TSA and should be applied to additional segments of Doudy Draw and to social trails with high priority invasives prior to construction of new trails.


Enormous ecological value and function will be lost from development of trails in the Doudy Draw/Spring Brook sub-area. A summary of some ecological damage and losses is presented below for proposed trail sections. The Trail Suitability Analyses give short shrift to this, not even using the information contained in the Inventory Report for the TSA.

The currently proposed main trail alignments (upper and lower 13 and 14) track long sections of the ecotone along the top/edge of pediment terraces, cutting off habitat upon which wild turkey, deer, elk, and other wildlife depend. These routes can be expected to affect turkey, deer, and elk populations, but much-needed pre- and post-monitoring is required to quantify the effects. Effects on forest nesting birds, particularly forest raptors also need to be monitored.

The proposed trail alignments repeatedly cross riparian areas and shrub communities. This configuration will draw visitors into these areas, which now provide important habitat for diverse species, as highlighted in the OSMP Inventory Report (see page 1 of these comments). The impact will be significant, since these trails are being planned as multiple-use trails: hikers, mountain bikers, equestrians, and dogs (on Trail 13), many of which can be expected to be off-leash, based on compliance data gathered so far by OSMP.

The trail alignment process has been rushed, and this rapid pace is unfortunately leading to poor choices. Some important alternative routes have not been considered in the haste to build trails during 2007 that will have permanent, detrimental impacts and bring additional visitors into the area. OSMP staff and the public should not be forced by political considerations to choose among inadequately studied, poorly conceived routes.

There is a lack of sufficiently detailed knowledge of natural resources along trail alignments and at the scale of impending impacts. (Prior to public comment on alignments, baseline monitoring plots have been established and data collection has begun along alignments which may not be the final/best routes.) This shortcoming stems from two factors: (1) Lack of specific monitoring. (2) Absence of detailed maps to guide decisions. The excellent Inventory Report did not consider resources at the trail scale—the scale of impacts caused by trails, ecotone disruption, and visitor behavior.

Sound planning would use newly developed maps that include the full range of resources that are typically considered in siting trails (e.g., wildlife presence and needs, ecotones, and invasive plants, soils, and geology [including scarps and slumps from landslides], as well as plant communities and areas of rare plants that are already mapped) all at the appropriate scale for planning routes and making decisions.

Some trails will funnel visitors (including a predictable proportion of off-leash dogs) into pristine areas of special, irreplaceable ecological values (e.g., Spring Brook area—mature forests, ecotones, and rare and relict terrace grasslands on the ancient pediment surface).

The proposed trail plan would promote increased off-trail travel into these pristine areas. As examples:

  • the trail through the southern part of Spring Brook meadow (brown on OSMP map) will feed an off-trail “desire line” down the meadow to Fowler Trail East and up the meadow to link with the Goshawk Ridge Trail bridge;
  • the proposed brown “ramp” from upper/lower 13 into Spring Brook area that parallels and is close to the stream bottom will invite visitation into the bottomlands, especially along the many gently sloping deer trails (widened by recent horse travel);
  • many short-cuts to link more directly to trail segments; those shortcuts will be used to avoid long, gentle, looping stretches of trails;
  • many tempting pathways into native grasslands, mature forests and riparian areas from upper 13.

FOBOS is concerned about safety issues and user conflicts — mountain bikes, dogs, hikers, and horses on very narrow trails, long parts of which will be cut into and run along very steep side-hills that make it difficult at best to step off the trail to give way for visitors that have the right-of-way. As another safety issue, it should be noted that this area is used by lions for deer hunting, always in-season.

Soils and substrates for most of the area have not been taken into account. This problem bears on suitability and sustainability of long sections of trails (much of upper 13 and upper 14, as well as all of lower 13 and lower 14 below the flat terrace surfaces).

The design of trail routes has been strongly controlled by topography and by limited criteria for construction standards. Routing along gentle grades results in unnecessarily long stretches of trails through important wildlife habitat and grasslands that are highly sensitive and vulnerable to plant invasion including spread of noxious weeds. In addition, the attempts to create ‘sustainable’ trails by limiting climbing grade and possible ponding of water are negated by the choice of routes that cut for long distances across very unstable side-hill slopes of Pierre Shale—the very opposite of sustainable.

Spring Brook area We recommend no trail in the Spring Brook area (such as “Trail 13- Spring Brook”) for the following reasons:

Exceptional habitat for deer and elk; possible presence of Preble’s Jumping mouse; lion hunting grounds; vulnerability to weed invasion, as demonstrated by high-priority weeds (such as Dalmatian toadflax and Sulfur cinquefoil) along the social trail.

Funneling visitors into Spring Brook will inevitably promote off-trail travel throughout the area, including the length of the meadow along the desire-line northward.

FOBOS requests that, if a trail is constructed in the Spring Brook area south of the meadow (as shown in brown), OSMP make and articulate detailed plans about (1) how it intends to control human, dog, and horse travel in this area; and (2) the conditions that would trigger trail closure if compliance is lacking.

“Ramp” Trail (shown on the OSMP map in brown) from Lower & Upper 13 into Spring Brook
A major problem with this alignment is the long “ramp” (about 1000-feet long, from top of terrace [pediment] surface gradually down into drainage) that traverses the steep wall. Most of this track generally parallels and is very close to the bottomland and offers continuous opportunities and temptations to drop off the trail down into the riparian area. Maintaining on-trail travel through here is merely wishful thinking. The route is also on unstable substrate of Pierre Shale.

The 13s
Lower and Upper Trail 13 have many failings (only some of which are adequately described in the Trail Suitability Analysis) and are unsuitable because they would:

  • result in excessive ecosystem degradation (incursions into several high-quality native grassland assemblages that are rare in the OSMP system and that could be avoided) and would unnecessarily fragment habitat;
  • provide pathways for invasion by weed species unless major control efforts are initiated prior to construction;
  • be built on unsuitable substrate that could be avoided, leading to an unsustainable trail (especially most of lower 13);
  • unnecessarily promote off-trail travel.

More details and documentation follow: Lower 13 cuts through large areas of otherwise uncommon and extraordinary grassland that includes at least 8 species of native grass and a native sedge (listed in appendix A).

Both upper 13 and lower 13 traverse across the old pediment and cut the relict native grassland that includes mountain muhly, a relict species in an extremely rare setting. This small area of less than about 10 acres should be protected. Trails can and should avoid passing through (as in several earlier plans) or even close to this habitat. Lower 13 also would pass by a prairie dog colony on the pediment that is expanding south.

Both upper and lower 13 will cut through an important and highly valuable forest/grassland ecotone as well as interior forest and consequently are highly disturbing.

Lower 13 is mostly on very step side-hill, with unstable shale substrate, that includes shrubland and native grassland communities (as described on page 1 of these comments).

Upper 13 offers many temptations to drop off the trail into riparian areas. The long track of lower 13 up the drainage will promote short-cutting across the drainage.

Trail 13 – Stem would be highly damaging to native grassland and to the riparian area, through which it cuts. There is the important question about the wetlands permit that is stated in the Suitability Analyses. Since this is one of very few drainages in the OSMP system that do not have trails in them, any crossings, if permitted, must take the least invasive route.

Nearly all of 13 Stem is unnecessary if lower 13 is not selected (see Alternative route for Stem Trail below.)

The 14s

Both trails would fragment habitat. Both upper and lower 14, as proposed, will cut through an important and highly valuable forest/grassland ecotone as well as interior forest and consequently are highly disturbing.

Lower 14 is mostly on a very step side-hill, with shale substrate, that includes shrubland and native grassland in places. In addition, as the OSMP Suitability Analysis points out, it may entice visitors into the Lindsay Pond and Bull Gulch areas.

Upper 14 cuts along the forest edge and wipes out a huge part of deer bedding ground in the area.

Of the two 14 alignments, Upper 14 is preferable – if only because its location will not allow visitors to look down on and be enticed to go to Lindsey Pond. As mentioned it will eliminate a substantial part of the ecotone – and wildlife’s access to it.

**Our first preference, as noted on p. 3 above, is to build Upper 14 and an Alternative Stem Trail once Doudy Draw high priority weeds are under control and baseline monitoring has been completed; to intensively monitor the impact of visitor use on these trail segments and use the results to inform decisions regarding the other ecotonal areas to the north and west; and to continue to explore options for Trail 13 alignments.

**Our Preferred Alternative route for Stem Trail (shown on Map 2)— from Doudy Draw to trails 13/14:

Connect with “Trail13 – Stem” at a point (39.92380/105.26014 [Map 2, STEM1]) close to the saddle (where it breaks from “potential Doudy Draw Re-Route”), continue in a route southwest and west to intersect with the junction of Trail 13 – Stem and Lower 14 at (39.92170/105.26331 [Map 2, STEM6]). Intermediate locations, connected by looping “as needed”, are:

  • 39.92319/105.26174 [STEM2], crosses first minor gulley to the west;
  • 39.92334/105.26226 [STEM 3], on ridge between the two drainages in the vicinity;
  • 39.92257/105.26208 [STEM 4], crosses railroad grade;
  • 39.92182/105.26229 [STEM5], on upper part of ridge.

A route similar to this will likely become a social trail anyway to move visitors directly to a 14 trail from the saddle.

**Our Preferred Alternative for Trail 13 is 13A (not shown on map) – Route 13A uses the existing, abandoned railroad (RR) grade to go northward from our “Alternative route for Stem Trail” around the terrace/mesa. We have investigated this option and found no conservation easements or legal constraints to prevent it. Staff has stated that there is a concern with a “spring”. A fence now separates the spring (which we believe to be the Spring of Concern) from the railroad grade where the two are in proximity. Bridges would be needed over the creek crossings, but use of the existing roadbed would avoid problems with the Pierre Shale. In addition, this route offers spectacular views, and many opportunities for interpretation – e.g. landscape level ecology and possibilities for highlighting different biological community types, geological formations, geomorphic features, watersheds, human history and land-use patterns. In addition it offers a trailbed that is: wide enough for the proposed multiple uses allowing safe passage; an existing human-constructed substrate so that new construction can focus on providing a durable trail surface, adequate drainage, bridges to connect segments of roadbed; and a route without major rare, sensitive, imperiled habitats, biological communities, or species of concern. Our proposed route goes from the RR grade to the west through the trees north of Spring Brook and crosses the brook at a place without dense shrub communities. We propose a bridge over the brook at this point with appropriate fencing/structures to both direct visitors to the connection with the “Fowler Trail East” roadbed (at a spot a short distance north of the hairpin turn and the start of the existing social trail) and to keep visitors from going down into the creekbed.

Advantages of Route 13A: This alignment would avoid the rare and threatened grassland communities on the mesa top, leave the Spring Brook meadow and the large block of mature Ponderosa forest and grasslands-forest ecotone unfragmented, minimize impacts to riparian crossings, and address the threat of the intrusion of invasive species into this rare habitat. In our view this is the only “13” route that will lead to fulfillment of the TSA Plan’s promise that “trails will not be built that would critically fragment large habitat blocks or create impacts to highly sensitive areas.”

Alternatives to OSMP Trail Alignments IF OSMP Proposed Trails must be built:
Route “Trail 13 – Springbrook” southward, staying east of Spring Brook and above it. Connect with Water Board Road east of Spring Brook. The part of the trail north of the current fence (currently grazed area) should be designated as “on-trail” only.

If “Trail 13 – Springbrook” must be routed across Spring Brook, a trail could easily have a more direct ingress into Spring Brook from the east, requiring steeper trail, perhaps with one or two switchbacks. Points on the terrace at which Upper 13 could drop off the terrace and join the “ramp” on a gentle grade (N lat/W long) are:

  • 39.92226/105.26909
  • 39.92245/105.26902 (connecting to the ramp at 39.92244/105.26922)

These points are shown as R1, R2, and R3 on Map 1, attached.
Alternative route for “Trail 13 – Upper” if that route must be built – (see red dotted line on Map 3, below) – if this alignment is chosen we prefer that it be placed further south than currently flagged to avoid rich, native grassland on the old pediment. (GPS points are given in Appendix B that could define this route [shown on Map 1 as 13ALT1 and 13ALT2]). This trail should also stay on the east side of Spring Brook and proceed south to the Denver Water Road.


  • Much of the proposed trail system will traverse steep hillsides (i.e., be cut into side-slopes of as much as 23 degrees). Unless trails are very wide, there will be little room to maneuver to avoid bikes, dogs, and horses that require wide passage. We note that staff has indicated trail width to be mostly about 30-inches wide, not enough room for other visitors to avoid horses.
  • Moving off-trail on the uphill side to avoid contact will be difficult for all but the most agile, and moving quickly off-trail on the downhill side would be treacherous for small children and those of limited mobility. For all visitors, agile or not, moving off trail will cause erosion on this loose slope.


Long stretches of the trail system are proposed for slopes in shale that are now unstable or that will likely become unstable and deeply eroded within a short period of time, unless engineered to stabilize at high cost and with significant impact. Overall, the costs of building and maintaining the trails would appear to be much higher than estimated.

  • Most of the proposed routes between Doudy Draw and the terrace surfaces to the west are in shale, and major segments of these tracks (lower 13 and lower14) are to be constructed with side cuts into steep slopes of shale.
  • Long, continuous sections of trails lower 13 and lower 14 would incise shale and slumped shale slopes between 18 and 23 degrees.
  • There is very high probability of undercutting slopes and initiating new slumps (unless uphill sides are anchored and buttressed). Staff indicated on the field trip (July 19, 2007) that upslope walls as much as 2-3 feet will result from trail building on these steep side hills.
  • Other long, continuous sections of trails 13 and 14 traverse the shoulders of terraces—the boulder-strewn, very steep hillsides (also on about 20-degree slopes) just below the terrace surfaces. Shale underlies these areas, as well. The cobbles and boulders are simply resting on the shale—they do not form a gravel surface as they do on the mesa top.


Trail routes are driven dominantly by three factors: (1) grade, (2) drainage, and (3) visitor experience, at the expense of natural values and resources.

The Suitability Analyses are very weak with respect to natural resources of wildlife and plant habitats, and the links between the two appear lacking.

Prevention of the spread of weeds and invasive plants is inadequate. Large sections of weeds on the paths into this area should be controlled before building these trails. Otherwise, there will be direct and immediate influx of weed seeds by many vectors (not just by trail construction, the only vector mentioned in the Suitability Analysis).

The planned trails will inevitably and unacceptably harm natural resources in the affected Natural Area. The trail layout will funnel visitors into highly sensitive and attractive landscapes, thereby directly promoting off-trail travel into these lands. There are alternatives that would be preferable environmentally and still provide an excellent visitor experience.


FOBOS believes that there is much room and opportunity for improvements to the trail alignments as currently flagged, and as presented on the public hike. FOBOS hopes that OSMP will consider closely our recommendations and alternative routings that would minimize ecological damage to the Natural Area and that may well cut trail-building and maintenance costs.

The current plan could be greatly improved by bringing together existing and new knowledge about valuable wildlife and plant resources to inform decisions. Moreover, a few important and viable options have not been considered.

FOBOS is deeply concerned about impacts of the proposed trails on wildlife and their habitats, as well as on native plant communities. Because of the lack of systematic monitoring of many critical ecological factors for at least a full year following route decisions and prior to the proposed 2007 trail construction, data are inadequate to assess with accuracy some of the impacts on species such as elk, bear, cougar, and turkey. In addition, the data are inadequate to determine acceptability levels and standards that will trigger future management decisions (see VMP). Further, the TSA Plan (Dec 8, 2006, p. 23) states that “more information will be needed where trails are proposed.” Without this, it will not be possible to “protect rare, imperiled, and highly-vulnerable resources,” “prevent the spread of invasive weeds,” “maintain viable habitats for the native plants and animals,” and “detect unintended impacts early…(to) ensure impacts to important resources are avoided, minimized and mitigated” as promised in the TSA (pp.8, 9, and 15).

Finally, FOBOS believes that this trail-building plan could be improved in many respects to bring trail alignments into compatibility and consistency with the stated importance and concern regarding conservation of valuable natural resources in the Natural Area. Many of the OSMP options on the table are unreasonably out-of-balance in favoring intensive recreation and the human visitor over the exceptional natural values in the Doudy Draw/Spring Brook subarea.

The plans for trails 13 and 14 are in many ways inconsistent with following stated guidelines and goals for Natural Areas in the Visitor Master Plan:

  • Accommodate low-impact visitor activities where adequate trails exist or can be built, and resource impacts can be minimized.
  • Protect the quality of natural …. resources (especially where high value resources exist).

High value resources do exist in the Doudy Draw/Spring Brook subarea, as documented in the Inventory Report and with subsequent observations by OSMP staff and volunteers.

The trail plan should be revised to provide for conservation of these priceless natural resources.

Appendix A

  • Native grasses and sedge in Lower 13 trail path
  • Big bluestem Tall dropseed (Eastern prairie [sporabalus])
  • Prairie dropseed (Eastern prairie [sporabalus])
  • Blue grama Mountain muhly (in relict, rare grassland on very old pediment surface)
  • Western wheatgrass
  • Sun sedge
  • June grass
  • Agassiz bluegrass

Appendix B

GPS points that define alternative routing of Trail upper 13 further south than currently flagged to avoid rich, native grassland on the old pediment. Points are east to west from current flagged route to the Water Board Rd.

  • 39.92136/105.26614 [Map 1 13ALT1], east end of alternative route at flagged tree
  • 39.92140/105.26824 [Map 1 13ALT2], west end of burned area (mostly open forest and healthy grassland) to Water Board Rd. north of bridge site.

This route achieves a loop trail. It also stays on the terrace surface more than about 30 m away from its edge above the Spring Brook area.