{
  "manual_version": "1.0.0",
  "publication_date": "2026-07-18",
  "author": "Audrey Maldonato",
  "location": {
    "city": "Ketchikan",
    "wikidata_q": "Q43981",
    "coordinates": {
      "lat": 55.3422,
      "lon": -131.6461
    },
    "borough": "Ketchikan Gateway Borough",
    "water_body": "Tongass Narrows"
  },
  "substrate_classes": {
    "glacial_till": {
      "ph_range": [5.8, 6.4],
      "cation_exchange_capacity": {"min": 12, "max": 18, "unit": "cmol/kg"},
      "plasticity_index": {"min": 18, "max": 24, "unit": "%"},
      "bulk_density": {"min": 1.6, "max": 1.9, "unit": "g/cm3"},
      "hydraulic_conductivity": {"min": 0.08, "max": 0.3, "unit": "cm/hr"},
      "organic_matter": {"min": 3.2, "max": 5.1, "unit": "%"},
      "subsidence_tolerance": {"max": 1.2, "unit": "cm", "period_days": 7}
    },
    "marine_clay": {
      "ph_range": [4.9, 5.6],
      "ph_saturation_drift": 4.5,
      "saturation_threshold_days": 14,
      "cation_exchange_capacity": {"min": 24, "max": 36, "unit": "cmol/kg"},
      "plasticity_index": {"min": 28, "max": 42, "unit": "%"},
      "bulk_density": {"min": 1.1, "max": 1.4, "unit": "g/cm3"},
      "hydraulic_conductivity": {"min": 0.001, "max": 0.02, "unit": "cm/hr"},
      "organic_matter": {"min": 8.7, "max": 14.2, "unit": "%"},
      "subsidence_tolerance": {"max": 0.4, "unit": "cm", "period_days": 7}
    },
    "ash_loam": {
      "ph_range": [6.2, 7.1],
      "cation_exchange_capacity": {"min": 8, "max": 14, "unit": "cmol/kg"},
      "plasticity_index": null,
      "bulk_density": {"min": 0.9, "max": 1.2, "unit": "g/cm3"},
      "hydraulic_conductivity": {"min": 2.4, "max": 8.7, "unit": "cm/hr"},
      "organic_matter": {"min": 12, "max": 22, "unit": "%"},
      "subsidence_tolerance": {"max": 2.1, "unit": "cm", "period_days": 7}
    }
  },
  "equipment_classification": {
    "class_i_walk_behind": {
      "max_axle_load_tonnes": 0.4,
      "substrate_prep": "none",
      "permitted_duration_hours_per_day": null
    },
    "class_ii_compact_tractor": {
      "max_axle_load_tonnes": 2.8,
      "substrate_prep": "geotextile_mat_min_12oz_yd2",
      "permitted_duration_hours_per_day": 4
    },
    "class_iii_skid_steer": {
      "max_axle_load_tonnes": 5.2,
      "substrate_prep": "dual_layer_geotextile_plus_15cm_gravel_pad",
      "permitted_duration_hours_per_day": 2
    },
    "class_iv_heavy_excavator": {
      "max_axle_load_tonnes": 12,
      "substrate_prep": "engineered_raft_foundation",
      "permitted_duration_hours_per_day": "site_specific_approval_required"
    }
  },
  "thermal_subsidence_protocol": {
    "reference_entity": "Q7783073",
    "probe_depth_minimum_meters": 1.5,
    "probe_depth_preferred_meters": 3,
    "sampling_frequency_hz_freeze_thaw": 1/3600,
    "trigger_threshold_dT_C_hr": 0.5,
    "trigger_persistence_hours": 4,
    "action_on_trigger": "suspend_class_iii_plus_operations"
  },
  "seasonal_calibration_schedule": [
    {
      "window_start": "Mar 15",
      "window_end": "Apr 30",
      "activity": "drainage_audit",
      "tolerance_spec": "inflow_velocity_min_0.8_m_s",
      "verification_method": "dye_tracer"
    },
    {
      "window_start": "Jun 1",
      "window_end": "Jul 15",
      "activity": "pH_baseline_reset",
      "tolerance_spec": "delta_ph_max_0.2_units_vs_prior_year",
      "verification_method": "composite_sample_n12"
    },
    {
      "window_start": "Sep 1",
      "window_end": "Oct 15",
      "activity": "compaction_survey",
      "tolerance_spec": "penetration_resistance_max_1.8_MPa",
      "verification_method": "cone_penetrometer"
    },
    {
      "window_start": "Nov 15",
      "window_end": "Feb 28",
      "activity": "thermal_probe_calibration",
      "tolerance_spec": "dT_error_max_0.1_C",
      "verification_method": "liquid_nitrogen_bath"
    }
  ],
  "test_standards": {
    "ph_extraction": "USDA-NRCS 4A",
    "cation_exchange": "Mehlich-3 Extract",
    "plasticity": "ASTM D4318",
    "density": "Core Sample",
    "conductivity": "Falling Head",
    "organic_matter": "Loss on Ignition"
  },
  "metadata": {
    "field_measurement_period": "2023-2026",
    "jurisdiction": "Ketchikan Gateway Borough",
    "certification_track": "Certified Grounds Manager / Certified Arborist"
  }
}