Exhibit 4 - Design Parameters.pdf

Trail Fundamentals - 45

Design Parameters (FSH 2309.18, Section 23.12, Exhibit 01)

Design Parameters are technical guidelines for the survey, design, construction, maintenance, and assessment of National Forest System trails, based on their Designed Use and Trail Class and consistent with their management intent1. Local deviations from any Design Parameter may be established based on trail-specific conditions, topography, or other factors, provided that the deviations are consistent with the general intent of the applicable Trail Class.

Designed Use PACK AND SADDLE Trail Class 1 Trail Class 2 Trail Class 3 Trail Class 4 Trail Class 5

Wilderness (Single Lane)

12” – 18” May be up to 48” along steep side slopes 48” – 60” or greater along precipices

18” – 24” May be up to 48” along steep side slopes 48” – 60” or greater along precipices

24” May be up to 48” along steep side slopes 48” – 60” or greater along precipices

Non-Wilderness (Single Lane)

12” – 24” May be up to 48” along steep side slopes 48” – 60” or greater along precipices

18” – 48” 48” – 60” or greater along precipices

24” – 96” 48” – 60” or greater along precipices

Non-Wilderness (Double Lane)

60” 60” – 84” 84” – 120”

Design Tread Width

Structures (Minimum Width)

Other than -bridges: 36” Bridges without handrails: 60” Bridges with handrails:

84” clear width

Other than bridges: 36” Bridges without handrails:

60” Bridges with handrails:

84” clear width

Other than bridges: 36” Bridges without handrails:

60” Bridges with handrails: 84” clear width

Type Native, with limited grading

May be frequently rough

Native, with some on-site borrow or imported material where needed for stabilization and occasional grading

Intermittently rough

Native, with improved sections of borrow or imported material and routine grading

Minor roughness

Protrusions ≤ 6” May be common and continuous

≤ 3” May be common, not continuous

≤ 3” Uncommon, not continuous

Design Surface2

Obstacles (Maximum Height)

Typically not designed or actively managed for equestrians, although use may be allowed

12”

6” 3”

Typically not designed or actively managed for equestrians, although use may be allowed

10/16/2008

Trail Fundamentals - 46

PACK AND SADDLE Trail Class 1 Trail Class 2 Trail Class 3 Trail Class 4 Trail Class 5

Target Grade 5% – 20%

3% – 12% 2% – 10%

Short Pitch Maximum

30% 20% 15%

Design Grade 2

Maximum Pitch Density 15% – 20% of trail

5% – 15% of trail 5% – 10% of trail

Target Cross Slope 5% – 10%

3% – 5% 0% – 5% Design Cross Slope Maximum Cross Slope 10%

8% 5%

Height 8’ – 10’

10’

10’ – 12’

Width 72” Some light vegetation may encroach into clearing area

72” – 96”

96”

Clearing

Shoulder Clearance 6” – 12” Pack clearance: 36” x 36”

12” – 18” Pack clearance: 36” x 36”

12” – 18” Pack clearance: 36” x 36”

Design Turn

Radius

4’ – 5’

5’ – 8’ 6’ – 10’

1 For definitions of Design Parameter attributes (e.g., Design Tread Width and Short Pitch Maximum) see FSH 2309.18, section 05.

2 The determination of trail-specific Design Grade, Design Surface, and other Design Parameters should be based upon soils, hydrological conditions, use levels, erosion potential, and other factors contributing to surface stability and overall sustainability of the trail.

Trail Fundamentals - 53

Design Parameters (FSH 2309.18, Section 23.23, Exhibit 01)

Design Parameters are technical guidelines for the survey, design, construction, maintenance, and assessment of National Forest System trails, based on their Designed Use and Trail Class and consistent with their management intent1. Local deviations from any Design Parameter may be established based on trail-specific conditions, topography, or other factors, provided that the deviations are consistent with the general intent of the applicable Trail Class.

FOUR-WHEEL DRIVE VEHICLE > 50" Trail Class 1 Trail Class 2 Trail Class 3 Trail Class 4 Trail Class 5

Single Lane 72” – 84”

72” – 96” 96” – 120”

Double Lane 16’

16’ 16’

Tread Width

Structures (Minimum Width)

96” 96” 96”

Type Native, with limited grading

May be continuously rough

Sections of soft or unstable tread on grades < 5% may be common and continuous

Native, with some on-site borrow or imported material where needed for stabilization and occasional grading

Intermittently rough

Sections of soft or unstable tread on grades < 5% may be present

Native, with imported materials for tread stabilization likely and routine grading

Minor roughness

Sections of soft tread uncommon

Protrusions ≤ 12” May be common and continuous

≤ 8” May be common and continuous

≤ 4” May be common and continuous

Design Surface2

Obstacles (Maximum Height)

36” May be common or placed for increased challenge

24” Common and left for increased challenge

12” Uncommon

Target Grade 10% – 21%

5% – 18% 5% – 12%

Short Pitch Maximum

25% 20% 15%

Grade2

Maximum Pitch Density

Typically not designed or actively managed for 4WD Vehicles > 50”, although use may be allowed

20% – 30% of trail

10% – 20% of trail 5% – 10% of trail

Typically not designed or actively managed for 4WD Vehicles > 50”, although use may be allowed

10/16/2008

Trail Fundamentals - 54

FOUR WHEEL DRIVE VEHICLE > 50" Trail Class 1 Trail Class 2 Trail Class 3 Trail Class 4 Trail Class 5

Target Cross Slope 8% – 15%

5% – 12% 5% – 8% Design Cross Slope Maximum Cross Slope 15%

12% 8%

Height 6’ – 8’

6’ – 8’ 8’ – 10’

Width 72” – 84” Some light vegetation may encroach into clearing area

72” – 96”

96” – 144”

Clearing

Shoulder Clearance 0” – 6”

6” – 12” 12” – 18”

Turn

Radius

10’ – 15’ 15’ – 20’ 20’ – 30’

1 For definitions of Design Parameter attributes (e.g., Design Tread Width and Short Pitch Maximum) see FSH 2309.18, section 05.

2 The determination of trail-specific Design Grade, Design Surface, and other Design Parameters should be based upon soils, hydrological conditions, use levels, erosion potential, and other factors contributing to surface stability and overall sustainability of the trail.