Statutory Civil Compliance & Earthwork Engine

Mountain Steep-Slope Feasibility & Permitting Engine

Deterministic site development evaluation based on the North Carolina Mountain Ridge Protection Act (NCGS § 113A-205) and County Unified Development Ordinances (Buncombe, Henderson, Haywood, Jackson). Calculates cut-and-fill mass balance, impervious surface caps, engineered retaining walls, and rock breaker mobilization.

Parcel Size (Acres) A_parcel

Average Natural Slope (%) Slope_%

Site Elevation Above Sea Level (Feet) Elev_ft

Subsurface Soil & Geology Profile Geol

Proposed Structural Envelope (Sq Ft) A_footprint

Civil Feasibility & Mass Balance Derivation

Estimated Civil Budget

$78,500 – $112,000

Max Impervious Cap

32,670 sq ft (30%)

Raw Cut Volume

1,420 cu yds

Compacted Fill Req.

1,225 cu yds

Mandatory Statutory & Municipal Permits:

Licensed PE Dispatch & Feasibility Brief

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Regulatory Framework & Mass Balance Equations

1. NC Mountain Ridge Protection Act (NCGS § 113A-205)

Parcels exceeding 3,000 feet in elevation with a natural crest line elevation 500+ feet above adjacent valley floors are designated protected mountain ridges. Structural height is legally restricted to 35 feet from average natural grade, and clearing of natural ridge vegetation is restricted to 15 feet from exterior structural footings.

2. UDO Steep Slope Threshold Matrix

              • <15% Slope: Standard Review (50% max impervious surface)

              • 15%–25%: Minor Steep Slope Review (40% impervious cap)

              • 25%–35%: Severe Steep Slope (30% impervious cap, no uncompacted fill)

              • >35%: Critical Slope (15% impervious, mandatory borehole geotech seal)

3. Cut-and-Fill Compaction Mass Balance

Hillside terracing requires balancing excavation cut with structural embankment fill:

              V_cut = (0.5 × W_bench × H_cut × L_bench) / 27

              V_fill_compacted = V_fill_raw × 1.15 (15% standard compaction shrink)

4. Rock Breaker Mobilization Contingency

When excavation on >25% grades encounters shallow granitic bedrock or saprolite ledges, standard excavator buckets reach refusal. A 5,000 ft-lb hydraulic breaker mounted on a 25-ton carrier ($240–$325/hr) is mobilized, adding $22–$35/cu yd across all ledge strata.