GEManualSec10StdsCodeRefPage

GRADING AND EXCAVATION MANUAL 2010 Edition

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SECTION 10: STANDARDS AND CODE REFERENCES

Listed in this section are the standards defined here and in the Code, with reference to the applicable section of the Code, that are subject to review by the Engineering Department. This list is intended to be used as a guideline for site design and planning, but does not include all of the regulations that may be applied by other agencies or departments. Be advised that any errors or omissions in this section shall not be construed to relieve the requirement of those standards. As always, the Engineering Department is available to discuss our regulations and how they are applied to any specific development proposal.

Grading Standards:

2:1 max. slope or retain

Retaining walls over 4-feet must be designed by a CO PE
Retaining walls over 4-feet onsite must be approved in a letter or as-built drawing by a CO PE

Positive drainage

Directed away from all structures
Directed towards appropriate destination (i.e. County road-side ditch, river, lake, or stream)
Drain daylighting must occur 20 feet from the County road-side ditches

Slope protection provided

Netting
Slope drains
Benching of fill
Furrows perpendicular to slope
Rip-rap or concrete swales

Proper grading procedures

Compacted fill to appropriate density and moisture content
Clean topsoil at top 6”
Finished grades to clean lines and grades, per plan
Include all utilities and any leach field finished grades

Driveway Standards (§5107.03: Standards for Driveway Design):

Location/separation (§5107.03.A & §5107.03.B)

30-ft from adjacent driveway, measured from flare edge to flare edge
50-ft from intersection, measured from driveway flare edge to edge of right-of-way for local access
Per left turn stacking distance for higher functional classifications

Grade (§5107.03.E)

6% max. multi-family, commercial, institutional or industrial
8% max. residential
Up to 12% in backcountry zoning, to limit disturbance
Parking pad (conforming to standards and §5107.04.F) in lieu of grade standard may be installed on lots platted prior to October 1, 1986

Driveway Width (Table 5-12 in Chapter 5: Road & Bridge Standards)

22-ft min. for multi-family, commercial; 65‘ min. centerline radius of curvature
12-ft min. for residential driveway w/length<200-ft serving one unit
14-ft min. for residential driveway w/length>200-ft serving one unit, or w/length<200-ft serving 2-4 units; 40’ min. centerline radius of curvature
16-ft min. for residential driveway w/length>200-ft serving 2-4 units; with 40 ‘ min. centerline radius of curvature

Driveway Openings (Table 5-12)

Openings are to be perpendicular to the right of way (§5107.03.M)
Min. 18’ to max. 24’ width at flares for lots serving on unit
Min. 20’ to max 24’ width at flares for lots serving 2 to 4 units
Min. 24’ to max 30’ width at flares for Multi-family lots
Min. 24’ width at flares for Commercial lots serving
Shared openings must have recorded easements

Turnouts and Turnarounds for Emergency Equipment (Table 5-12)

Length <400 feet - no turnouts required
Length 400-800 feet - one 8’ x 30’ turnout at midway point; one turnaround for emergency equipment within 150’ of dwelling unit
Length >800 feet – every 400 feet, place 8’ x 30’ turnout; one turnaround for emergency equipment within 150’ of dwelling unit
Multifamily, Industrial, Commercial – one turnaround as specified in Figure 5-7 if the driveways dead end

Surfacing (§5107.03.G)

Class VI road base or recycled asphalt, 4” min. depth, on SFR’s or duplexes on gravel roads
Paved for duplexes and multi-family, commercial, etc… w/4” compacted base course and 2” min Hot Mix Asphalt (HMA), in accordance with §5103.03.C and §5203.09

Sight distance (§5107.03.I and Table 5-4)

200-ft min. on local access roads
400-ft min. on collectors

Drainage (§5107.03H and per this manual)

Away from structure, towards appropriate destination
Culvert per right-of-way permit

15”Æ min.
6” min. cover
Or as required by Road & Bridge Department

Snow storage (§5107.03.L)

25% of driving surfaces to be provided as snow storage
Must be in logical, accessible location, separate but adjacent to driving surfaces
Must be provided off right-of-way, on owners property

Wetlands and surface water standards (Chapter 7: Water Quality Control Regulations)

25-foot setback applies at all locations
Strict erosion control standards will apply in all cases where grading is proposed adjacent to surface waters, wetlands, or their setbacks
A financial guarantee for the cost of wetland mitigation or setback enhancement will be required prior to issuance of a GE permit on any project where wetland disturbance or surface water impacts are required, unless specifically waived in writing by the County Engineer
Exemptions may be granted per §7200 at the sole discretion of the County Engineer

GRADING AND EXCAVATION MANUAL 2010 Edition

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