Islands of Agrigan, Alamagan, Anatahan, Pagan, and Sarigan, Commonwealth of the Northern Mariana Islands
The most common soil here is Haplustands, on about 16% of the land. Hatisu and Plasanbola come next.
About 83% of the land drains well.
USDA rates 98% of the land very limited for a standard septic drain field, and 89% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: bedrock lies within 40 inches under 55% 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 Islands of Agrigan, Alamagan, Anatahan, Pagan, and Sarigan, Commonwealth of the Northern Mariana Islands, 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 D (very slow infiltration, high 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 Islands of Agrigan, Alamagan, Anatahan, Pagan, and Sarigan, Commonwealth of the Northern Mariana Islands. 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 |
|---|---|---|---|---|---|
| Haplustands-Rock outcrop complex, 45 to 150 percent slope | 7K | Well drained | D | Very limited | Very limited |
| Hatisu-Apilam complex, 45 to 150 percent slopes | 5K | Well drained | B | Very limited | Very limited |
| Plasanbola very gravely highly organic ashy loam, 35 to 125 percent slopes | 3K | Well drained | D | Very limited | Very limited |
| Apilam ashy silt loam, 45 to 150 percent slopes | 2K | Moderately well drained | D | Very limited | Very limited |
| Vitrandic Ustorthents-Cinder land complex, 15 to 35 percent | 2K | Well drained | A | Somewhat limited | Very limited |
| Rock outcrop, escarpment-Rubble land complex, 45 to 150 percent slopes | 2K | D | Very limited | Very limited | |
| Songsong ashy loam, 45 to 100 percent slopes | 1K | Well drained | B | Very limited | Very limited |
| Plasanbola-Rock outcrop complex, 45 to 125 percent slopes | 1K | Well drained | D | Very limited | Very limited |
| Cinder land, `a`a lava substratum-Rock outcrop complex, 45 to 125 percent slopes | 947 | Well drained | Very limited | Very limited | |
| Apilam ashy silt loam, 15 to 45 percent slopes | 933 | Moderately well drained | D | Very limited | Very limited |
| Lava flows, `a`a lava, 0 to 45 percent slopes | 807 | Excessively drained | Very limited | Very limited | |
| Cinder land-Rock outcrop-Vitrandic Ustorthents complex, 10 to 45 percent slopes | 639 | Well drained | Very limited | Very limited | |
| Lava flows-Vitrandic Ustorthents, sandy complex, 45 to 100 percent slopes, extremely stony | 607 | Excessively drained | Very limited | Very limited | |
| Shomushon-Cinder land complex, 15 to 45 percent slopes | 559 | Well drained | A | Very limited | Very limited |
| Dekairu ashy fine sandy loam, 15 to 45 percent slopes | 517 | Well drained | C | Very limited | Very limited |
| Songsong ashy loam, 15 to 45 percent slopes | 510 | Well drained | B | Very limited | Very limited |
| Lava flows, coastal escarpments, 0 to 99 percent slopes | 493 | Excessively drained | Very limited | Very limited | |
| Vitrandic Ustorthents, colluvial, 15 to 45 percent slopes | 472 | Well drained | A | Very limited | Very limited |
| Cinder land-Rock outcrop-Vitrandic Ustorthents complex, 35 to 100 percent slopes | 457 | Well drained | Very limited | Very limited | |
| Rock outcrop, tuff escarpments-Cinder land complex, 45 to 150 percent slopes | 419 | D | 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 89% 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.