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

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

In short: Tivoli is a very deep sandy soil that formed in wind-blown dune sand along river valleys in northwestern Oklahoma. It is sandy throughout, drains excessively and has no clay subsoil, so clay shrink-swell is not its main foundation issue. Instead, foundation concerns on Tivoli land center on how loose sand behaves around water, slopes and footings.

Where does Tivoli soil occur?

The USDA Natural Resources Conservation Service (NRCS) keeps an Official Series Description (OSD) for each named soil. Tivoli was established in Major County, Oklahoma, in 1936, and its type location is about 2.5 miles northeast of Woodward in Woodward County ¹. The OSD places it in Major Land Resource Areas 78B and 78C in Oklahoma, Kansas and Texas, and calls it extensive ¹.

Tivoli forms on sand dunes on sand sheets and stream terraces in river valleys and dissected plains, with hummocky relief and complex slopes of 1 to 45 percent ¹. "Eolian" means wind-deposited; Tivoli's parent material is sandy eolian sediment ¹. That places it in the Northwest (Gypsum Hills) on sandy deposits along major rivers, part of the Quaternary alluvium and terraces group. The land is mostly used for grazing, with sand bluestem, sand dropseed and sand reedgrass as native cover ¹.

What are Tivoli soil's key properties?

"Psamments" are sandy soils with little horizon development. Tivoli has no B horizon; a sandy surface layer sits on sandy C layers, in places with a transitional AC layer between ¹. "Single grain" means the sand grains do not stick together into clods ¹.

What does Tivoli soil mean for foundations?

Little shrink-swell

NRCS rates shrink-swell by linear extensibility, with under 3 percent classed as low ³. Tivoli has no clay-rich layer at all, so it lacks the material that drives seasonal swelling ¹. The rated value for a map unit is in Web Soil Survey ².

Loose sand, water and slopes

Because the sand is single grain and drains rapidly, water from roofs, leaks or broken lines soaks in and moves through quickly ¹. How concentrated water moves soil from beside and beneath footings is covered on erosion, undermining and washout voids. The ASCE homeowner guide recommends at least 3 inches of fall over the first 5 feet from the house, downspouts that discharge at least 3 feet out, and compacted clay rather than sandy soil for backfill against the foundation so it sheds water ⁴.

Tivoli slopes range up to 45 percent ¹; where a building pad was leveled with placed soil, fill consolidation settlement is a separate question from the native sand. Wind-deposited soils are also screened for collapse behavior; see collapsible and loess soils and hydrocollapse.

Climate

Northwestern Oklahoma's rainfall on Tivoli land averages about 26 inches a year ¹. The Oklahoma Mesonet runs 120 automated weather stations, with at least one in every county, for tracking local rainfall ⁵.

Related

• Pratt soil
• Woodward soil
• Collapsible and loess soils
• Slope and erosion stabilization
• Soil Series Index