North Cascades National Park Complex, Washington
The most common soil here is Doubtful, on about 10% of the land: a gravelly ashy sandy loam, gritty and crumbly. Stetattle and Perfect come next.
About 72% of the land drains well; groundwater comes within two feet of the surface under 4% of it.
USDA rates 98% of the land very limited for a standard septic drain field, and 98% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: 1% of the land floods occasionally or more, and bedrock lies within 40 inches under 80% of it.
Soils change over short distances, so look up an address below for the soil at that exact spot and the reasons behind each rating.
The soils you're most likely standing on
The biggest named soils in North Cascades National Park Complex, Washington, each drawn five feet deep from its official USDA description, in its recorded colors.
Dots mark gravel; white flecks mark lime. Shares are by acres across the survey area, and each mapped patch usually mixes several of these soils.
The biggest mapped areas
The dominant drainage class is Well drained and the dominant hydrologic group is A (high infiltration, low runoff). The most common soil order is Andisols — soils formed in volcanic ash, very light and porous. 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 North Cascades National Park Complex, Washington. Search your address to find the exact soil composition, drainage, and series details at your specific location.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Rock outcrop-Glaciers-Harlequin complex, 25 to 100 percent slopes | 144K | Very limited | Very limited | ||
| Doubtful-Treen-Rock outcrop complex, 35 to 100 percent slopes | 73K | Well drained | D | Very limited | Very limited |
| Doubtful-Triumph-Perfect complex, 35 to 100 percent slopes | 68K | Well drained | B | Very limited | Very limited |
| Mox-Doubtful-Perfect complex, 35 to 100 percent slopes | 55K | Well drained | A | Very limited | Very limited |
| Stetattle-Doubtful-Arriva complex, 15 to 100 percent slopes | 52K | Well drained | B | Very limited | Very limited |
| Spickard-Tepeh-Maggib complex, 15 to 100 percent slopes | 52K | Well drained | A | Very limited | Very limited |
| Thorton-Ragged-Benzarino complex, 35 to 100 percent slopes | 37K | Well drained | A | Very limited | Very limited |
| Stetattle-Forbidden-Triumph complex, 15 to 65 percent slopes | 22K | Well drained | A | Very limited | Very limited |
| Despair-Goode-Rock outcrop complex, 35 to 100 percent slopes | 18K | Well drained | A | Very limited | Very limited |
| Rock outcrop-Despair complex, 35 to 100 percent slopes | 18K | Very limited | Very limited | ||
| Water | 17K | Not rated | Not rated | ||
| Thorton-Ragged-Ledeir complex, 15 to 65 percent slopes | 14K | Well drained | A | Very limited | Very limited |
| Benzarino-Ragged-Rock outcrop complex, 35 to 100 percent slopes | 11K | Well drained | D | Very limited | Very limited |
| Tricouni-Ragged-Easy complex, 5 to 50 percent slopes | 11K | Well drained | A | Very limited | Very limited |
| Stehekin-Primus-Stetattle complex, 35 to 100 percent slopes | 10K | Well drained | A | Very limited | Very limited |
| Noca-Perfect complex, 35 to 100 percent slopes | 10K | Well drained | A | Very limited | Very limited |
| Farway-Sawtooth-Despair complex, 35 to 100 percent slopes | 10K | Well drained | A | Very limited | Very limited |
| Chilliwack-Perfect-Terror complex, 15 to 65 percent slopes | 10K | Well drained | A | Very limited | Very limited |
| Perfect-Spickard-Stetattle complex, 15 to 65 percent slopes | 8K | Well drained | A | Very limited | Very limited |
| Chilliwack-Forbidden-Stetattle complex, 15 to 65 percent slopes | 6K | Well drained | A | Very limited | Very limited |
Soil Orders in This Area
The USDA classifies every soil into one of 12 soil orders. Here are the dominant orders found in this survey area.
What This Means
Building & Foundations
About 98% 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 98% 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.