Channel Islands Area, California, Parts of Santa Barbara and Los Angeles Counties
The dominant drainage class is Well drained and the dominant hydrologic group is D (very slow infiltration, high runoff). This report summarizes the major soil map units across the survey area to help you understand what to expect when buying, building, or gardening in Channel Islands Area, California, Parts of Santa Barbara and Los Angeles Counties.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Rock outcrop-Spinnaker-Topdeck complex, 30 to 80 percent slopes | 11K | D | Not rated | Not rated | |
| Dewpoint-Masthead-Coastwise complex, 20 to 55 percent slopes | 9K | Well drained | D | Very limited | Very limited |
| Masthead-Coastwise-Dewpoint complex, 20 to 55 percent slopes | 9K | Well drained | D | Very limited | Very limited |
| Windage-Typic Xerorthents-Buoy complex 30 to 75 percent slopes | 9K | Well drained | C | Very limited | Very limited |
| Spinnaker-Starboard-Rock outcrop complex, 30 to 75 percent | 8K | Somewhat excessively drained | D | Very limited | Very limited |
| Oboship-Nauti-Bosun complex, 50 to 75 percent slopes | 7K | Well drained | B | Very limited | Very limited |
| Ahoy-Hawser complex, 2 to 30 percent slopes | 7K | Moderately well drained | C | Very limited | Very limited |
| Fantail, thin surface-Forestay-Fantail association, 20 to 75 percent slopes | 7K | Well drained | C | Very limited | Very limited |
| Typic Durixerolls, 5 to 15 percent slopes | 6K | Well drained | D | Somewhat limited | Very limited |
| Windage-Hawser-Typic Haploxeralfs complex 30 to 65 percent slopes | 5K | Well drained | C | Very limited | Very limited |
| Ustalfs-Rock outcrop complex, 30 to 100 percent slopes | 5K | Well drained | D | Very limited | Very limited |
| Windage-Buoy complex 30 to 50 percent slopes | 5K | Well drained | C | Very limited | Very limited |
| Masthead-Coastwise-Typic Haploxeralfs complex, 45 to 75 percent slopes | 4K | Well drained | D | Very limited | Very limited |
| Buoy-Rock outcrop-Ballast complex, 30 to 75 percent slopes | 4K | Well drained | C | Very limited | Very limited |
| Rock outcrop | 4K | D | Not rated | Not rated | |
| Lodestone-Typic Xerorthents-Windage complex, 25 to 60 percent slopes | 4K | Moderately well drained | D | Very limited | Very limited |
| Eelcove-Sanclemente-Ustalfs association, 2 to 75 percent slopes | 4K | Well drained | D | Very limited | Very limited |
| Shoba-Thirst-Rock outcrop association, 2 to 30 percent slopes | 3K | Well drained | D | Very limited | Very limited |
| Nauti-Flyer-Marpol complex, 25 to 55 percent slopes | 3K | Well drained | C | Very limited | Very limited |
| Fiale-Tongva-Topdeck association, 15 to 60 percent slopes | 3K | Moderately well drained | D | Very limited | Very limited |
What This Means
Building & Foundations
About 82% of soils are rated "very limited" for dwellings with basements. Specific challenges include shallow bedrock, steep slopes. A geotechnical assessment is recommended before building.
Septic Systems
About 87% of soils are rated "very limited" for septic absorption fields. Despite good drainage overall, limitations may stem from shallow bedrock, steep slopes, or seasonal conditions. Engineered or alternative systems are frequently required. Always get a professional perc test before purchasing land that needs septic.
Gardening & Agriculture
Well-drained soils on sloped terrain — good for most plants but watch for erosion. Terracing, contour planting, and mulching help retain moisture and topsoil. Drip irrigation is more effective than sprinklers on slopes.