What is Taloka soil and how does it affect Oklahoma foundations?

Reviewed by Preston, Oklahoma foundation repair consultant · Updated 2026-10-14

In short: Taloka is a very deep soil of northeastern Oklahoma with a silty surface that changes abruptly to a dense clay subsoil. It is somewhat poorly drained and holds a perched water table 12 to 24 inches down from late fall through spring. For foundations, the clay subsoil and the seasonal wetness are the main factors.

Where does Taloka soil occur?

The USDA Natural Resources Conservation Service (NRCS) keeps an Official Series Description (OSD) for every named soil. The Taloka OSD lists the series in Major Land Resource Areas 112, 116 and 118 of northeastern Oklahoma, northwestern Arkansas and southeastern Kansas, with moderate extent ¹. Its type location is in Wagoner County, about 4 miles southeast of Wagoner ¹.

Taloka forms on interfluves and paleoterraces (old, high stream terraces) on plains with 0 to 3 percent slopes ¹. It developed in loamy and clayey colluvium or alluvium weathered from interbedded Pennsylvanian shales and sandstone, sometimes with a thin loess cap ¹. That puts it in the Tulsa Metro and the Northeast. Most Taloka land is farmed for small grains, sorghum and soybeans ¹.

What are its key properties?

The "E" horizon is a pale, leached layer above the subsoil; in Taloka it runs from about 8 to 28 inches and ends at an abrupt boundary where texture jumps to silty clay or clay loam ¹. Redox features (gray and rust mottles that form under repeated saturation) appear in all layers below 8 inches ¹.

Parsons is a competing series on similar landforms, and Choteau, Dennis and Bates occur nearby ¹.

What do the properties mean for foundations?

A clay layer under a silty cap

With 35 to 60 percent clay, Taloka's subsoil can shrink when it dries and swell when it wets ¹⁴. The OSD does not record deep cracks or slickensides for this series ¹. NRCS rates shrink-swell by linear extensibility, and values above 3 percent can damage buildings and commonly call for special design ³. The rated value for a specific map unit is in Web Soil Survey ². Lab tests such as plasticity index are described on soil testing and lab values.

Perched water and slow drainage

A perched water table is water held up temporarily above a slow-draining layer. On Taloka it sits 12 to 24 inches down from November through May in normal years ¹. HUD's soil guide identifies water table depth, natural drainage and seepage as key controls on soil moisture, and notes that lawn watering and covering the soil also change it ⁵. Seasonal saturation is linked to crawl space moisture, perimeter wetting heave and water pressure on basement walls.

Dry summers

The same clay can shrink in hot, dry weather. HUD notes that vegetation can worsen shrinkage during warm, dry periods ⁵, and the ASCE guide links non-uniform drying near trees to uneven settlement ⁴. See perimeter drying settlement.

Related

• Groundwater and perched water
• Soil series in the Tulsa metro
• Parsons soil
• Drainage solutions
• Soil Series Index