Angeles National Forest Area, California
The dominant drainage class is Somewhat excessively 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 Angeles National Forest Area, California.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Trigo, granitic substratum-Exchequer families-Rock outcrop complex, 60 to 100 percent slopes | 53K | Somewhat excessively drained | D | Very limited | Very limited |
| Caperton-Trigo, granitic substratum-Lodo families complex, 50 to 85 percent slopes | 40K | Well drained | D | Very limited | Very limited |
| Rock outcrop-Chilao family-Haploxerolls, warm association, 15 to 120 percent slopes | 36K | D | Very limited | Very limited | |
| Lodo-Modesto families complex, 30 to 70 percent slopes | 28K | Somewhat excessively drained | D | Very limited | Very limited |
| Rock outcrop-Lithic Xerorthents-Rubble land association, 60 to 120 percent slopes | 23K | Excessively drained | D | Very limited | Very limited |
| Pismo-Chilao-Shortcut families complex, 45 to 80 percent slopes | 22K | Somewhat excessively drained | D | Very limited | Very limited |
| Trigo-Calleguas families-Haploxeralfs complex, 30 to 70 percent slopes | 20K | Well drained | D | Very limited | Very limited |
| Caperton-Capistrano families complex, 35 to 80 percent slopes | 20K | Well drained | D | Very limited | Very limited |
| Stukel-Sur-Winthrop families complex, 60 to 100 percent slopes | 19K | Somewhat excessively drained | D | Very limited | Very limited |
| Trigo, granitic substratum-Exchequer families-Rock outcrop complex, 30 to 60 percent slopes | 18K | Somewhat excessively drained | D | Very limited | Very limited |
| Bakeoven family-Lithic Xerorthents-Sur family, moderately deep complex, 45 to 80 percent slopes | 18K | Well drained | D | Very limited | Very limited |
| Pismo family-Rock outcrop complex, 50 to 80 percent slopes | 18K | Somewhat excessively drained | D | Very limited | Very limited |
| Stonyford-Millsholm families complex, 30 to 70 percent slopes | 16K | Well drained | D | Very limited | Very limited |
| Pismo-Trigo, dry-Exchequer, dry families complex, 30 to 70 percent slopes | 16K | Somewhat excessively drained | D | Very limited | Very limited |
| Rubble land-Rock outcrop complex, 50 to 100 percent slopes | 14K | Excessively drained | Very limited | Very limited | |
| Waterman-Springdale-Pacifico families complex, 30 to 70 percent slopes | 13K | Somewhat excessively drained | D | Very limited | Very limited |
| Typic Xerorthents, warm, 55 to 90 percent slopes | 12K | Excessively drained | A | Very limited | Very limited |
| Vista-Trigo, granitic substratum-Modesto families complex, 40 to 70 percent slopes | 12K | Well drained | D | Very limited | Very limited |
| Trigo family, dry-Lithic Xerorthents, warm complex, 50 to 80 percent slopes | 12K | Somewhat excessively drained | B | Very limited | Very limited |
| Haploxerols, shallow-Lithic Xerorthents, warm complex, 45 to 75 percent slopes | 12K | Well drained | D | Very limited | Very limited |
What This Means
Building & Foundations
About 100% of soils are rated "very limited" for dwellings with basements. Specific challenges include shallow bedrock, steep slopes, sandy or gravelly soils with low bearing capacity. A geotechnical assessment is recommended before building.
Septic Systems
About 100% of soils are rated "very limited" for septic absorption fields. The well-drained soils may actually drain too fast for standard leach fields, allowing effluent to reach groundwater. Engineered or alternative systems are frequently required. Always get a professional perc test before purchasing land that needs septic.
Gardening & Agriculture
Soils tend to drain very quickly, meaning nutrients and water don't stick around long. Raised beds with amended soil, drip irrigation, and heavy mulching will give the best results. Compost is your best friend here — it improves water retention dramatically.