Joshua Tree National Park, 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 Joshua Tree National Park, California.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Blackeagle-Rock outcrop complex, 15 to 75 percent slopes | 58K | Somewhat excessively drained | D | Very limited | Very limited |
| Rock outcrop-Blackeagle complex, 30 to 75 percent slopes, dry | 52K | D | Not rated | Not rated | |
| Goldenhills-Bulletproof-Fanhill-Whiterobe complex, 30 to 75 percent slopes | 37K | Somewhat excessively drained | A | Very limited | Very limited |
| Rock outcrop-Blackeagle complex, 30 to 75 percent slopes | 36K | D | Very limited | Very limited | |
| Desertqueen-Hexie-Rock outcrop, 15 to 50 percent slopes | 36K | Well drained | D | Very limited | Very limited |
| Pintobasin gravelly sand, 1 to 3 percent slopes, rarely flooded | 24K | Somewhat excessively drained | A | Very limited | Very limited |
| Seanna-Grubstake-Pinecity complex, 30 to 75 percent slopes | 22K | Well drained | D | Very limited | Very limited |
| Meccapass-Bulletproof-Rock outcrop complex, 30 to 75 percent slopes | 18K | Well drained | A | Very limited | Very limited |
| Xeric Torriorthents-Bigbernie association, 30 to 75 percent slopes | 17K | Somewhat excessively drained | A | Very limited | Very limited |
| Ironped-Rock outcrop-Hexie complex, 30 to 60 percent slopes | 16K | Somewhat excessively drained | D | Very limited | Very limited |
| Jadestorm-Blackeagle-Rock outcrop complex, 15 to 50 percent slopes | 16K | Somewhat excessively drained | D | Very limited | Very limited |
| Smithcanyon-Pinecity association, 15 to 50 percent slopes | 15K | Somewhat excessively drained | D | Very limited | Very limited |
| Rock outcrop-Jadestorm complex, 30 to 60 percent slopes | 15K | D | Not rated | Not rated | |
| Pintobasin-Carrizo complex, 2 to 8 percent slopes | 15K | Somewhat excessively drained | A | Not limited | Very limited |
| Morongo loamy sand, 2 to 4 percent slopes | 12K | Somewhat excessively drained | A | Very limited | Very limited |
| Perurose-Coxpin-Pintobasin association, 2 to 15 percent slopes | 11K | Somewhat excessively drained | A | Somewhat limited | Very limited |
| Oldale-Carrizo complex, 2 to 8 percent slopes | 11K | Well drained | A | Not limited | Very limited |
| Pinecity loamy sand, 2 to 8 percent slopes | 11K | Somewhat excessively drained | D | Very limited | Very limited |
| Carrizo-Rubylee complex, 1 to 4 percent slopes | 10K | Excessively drained | A | Not limited | Very limited |
| Pintobasin-Joetree-Patscamp complex, 2 to 8 percent slopes | 10K | Somewhat excessively drained | A | Very limited | Very limited |
What This Means
Building & Foundations
About 74% of soils are rated "very limited" for dwellings with basements. Specific challenges include shallow bedrock, steep slopes, flood-prone areas, sandy or gravelly soils with low bearing capacity. A geotechnical assessment is recommended before building.
Septic Systems
About 84% 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.