Kofa Area, Arizona, Parts of La Paz and Yuma Counties
The dominant drainage class is Somewhat excessively drained and the dominant hydrologic group is A (high infiltration, low 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 Kofa Area, Arizona, Parts of La Paz and Yuma Counties.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Hyder-Plomosa-Rock outcrop complex, 3 to 70 percent slopes | 381K | Somewhat excessively drained | D | Very limited | Very limited |
| Gunsight, Guvo and Hyder soils, and rock outcrop, 5 to 90 percent slopes | 287K | Well drained | D | Very limited | Very limited |
| Gunsight-Cristobal complex, dry, 1 to 10 percent slopes | 224K | Somewhat excessively drained | A | Not limited | Not limited |
| Momoli-Carrizo family complex, 1 to 5 percent slopes | 220K | Somewhat excessively drained | A | Very limited | Somewhat limited |
| Gunsight-Rillito complex, 1 to 10 percent slopes | 198K | Somewhat excessively drained | A | Not limited | Not limited |
| Carrizo family-Riverbend family-Riverwash complex, dry, 0 to 3 percent slopes | 181K | Excessively drained | A | Very limited | Very limited |
| Rock outcrop-Plomosa-Hyder complex, dry, 3 to 45 percent slopes | 167K | Somewhat excessively drained | D | Very limited | Very limited |
| Gunsight, Guvo and Hickiwan soils, 2 to 35 percent slopes | 150K | Somewhat excessively drained | D | Very limited | Very limited |
| Gunsight family-Gypsic Haplosalids-Gypsic Haplosalids, eroded complex, dry, 1 to 15 percent slopes | 141K | Somewhat excessively drained | A | Somewhat limited | Not limited |
| Gunsight-Pinamt complex, 1 to 15 percent slopes | 133K | Well drained | A | Not limited | Not limited |
| Hickiwan-Gunsight complex, 3 to 30 percent slopes | 117K | Somewhat excessively drained | D | Very limited | Very limited |
| Gunsight very gravelly sandy loam, dry, 1 to 8 percent slopes | 104K | Somewhat excessively drained | A | Not limited | Not limited |
| Denure-Rillito-Pahaka complex, 0 to 1 percent slopes | 103K | Somewhat excessively drained | A | Very limited | Somewhat limited |
| Rock Outcrop-Hyder-Guvo-Gunsight complex, 5 to 80 percent slopes | 96K | Well drained | D | Very limited | Very limited |
| Bosa, Garzona and Hulda family soils, and Rock outcrop, 10 to 90 percent slopes | 90K | Well drained | D | Very limited | Very limited |
| Cellar-Hulda family-Rock outcrop complex, 5 to 90 percent slopes | 89K | Somewhat excessively drained | D | Very limited | Very limited |
| Superstition-Coolidge-Rositas family complex, dry, 0 to 6 percent slopes | 86K | Excessively drained | A | Not limited | Not limited |
| Gunsight family-Typic Calcigypsids complex, dry, 5 to 45 percent slopes | 82K | Somewhat excessively drained | A | Very limited | Very limited |
| Denure-Pahaka-Wellton complex, 0 to 3 percent slopes | 78K | Well drained | A | Very limited | Somewhat limited |
| Gunsight, Guvo and Hyder soils, and rock outcrop, dry, 5 to 90 percent slopes | 64K | Well drained | D | Very limited | Very limited |
What This Means
Building & Foundations
About 70% 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 56% 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.