Crushed Rock, Gravel and Soil Delivery in Omaha, NE

Clay That Moves

At the ZIP's center point, the USDA survey maps the Urban land-Udorthents complex, 0 to 10 percent slopes, occasionally flooded. Urban land, paved or built over, covers 59 percent of the unit, and the Albaton series accounts for 5 percent. The top mineral layer is silty clay.^[1]

Shrink-swell in the top 100 cm is rated very high, at 12 percent linear extensibility. A soil like that swells noticeably when it soaks up water and shrinks and cracks as it dries. Anything laid directly on it, from a slab to a stepping stone, rises and falls with the seasons.^[1]

The survey rates the Albaton soil poorly drained, in hydrologic group D with very slow infiltration and high runoff. Rain sits on top of silty clay or sheds off it rather than soaking in, and the ground stays wet long after a storm.^[1]

Udorthents are soils that have been cut, filled or reworked, which is common close to a city center. What sits a spade's depth down can be a mix of clay, fill and debris, so dig a test hole before deciding on base depth.^[1]

Rock Below and Ground Height

The mapped bedrock unit at the center point is the Kansas City Group, layers of limestone and shale from the Pennsylvanian period.^[2]

The USGS reading for ground height at the ZIP's center point is about 990 feet above sea level.^[3]

For a driveway or patio, the bedrock rarely comes into the picture. The swelling clay and fill above it are what the project has to deal with, and they shape every choice about fabric, base thickness and drainage.^[1]

Snow, Ice and a Long Cold Season

Omaha Eppley Airfield, NE, about 4 miles away, is the NOAA normals station for this ZIP. It averages 31.9 inches of precipitation and 27.1 inches of snowfall a year.^[4]

Eppley logs 135 days a year when the low reaches 32 F or colder. The median last spring freeze there is April 18, and the median first fall freeze is October 21.^[4]

Clay that holds water and freezes is the classic recipe for frost heave. Each freeze turns trapped water into ice lenses that push the surface up, and each thaw leaves the ground soft. A gravel drive survives this only if water drains out of the base before it freezes.^[1],[4]

Grit and salt from plowed streets end up along the edge of a gravel drive over the winter. Rake that edge in spring and top it with fresh stone so the grit does not clog the surface.^[4]

Spring thaw is the weak point. As the snow melts and the top of the clay softens while the ground below stays frozen, a thin base turns to mud under tires. Thickness and good stone carry a drive through those weeks.^[4]

Building a Drive on Swelling Clay

Dig out the topsoil and any soft or organic material, then grade the clay so water flows off to the sides. On silty clay, roll out a woven geotextile fabric before any stone goes down. Without it, the clay pumps up into the base each time it gets wet and the stone slowly disappears.^[1]

Lay a thick bottom course of 1-1/2" Crushed Gravel or #4 Crushed Stone and compact it. The large angular pieces bridge over soft spots and give water room to drain. Follow with compacted Road Base, which binds into a firm, tight layer that sheds rain from the surface.^[1]

Finish with 3/4" Crushed Stone or #57 Crushed Stone. A crowned surface and ditches or a Drain Rock trench along the low side give water a way out, which matters on a soil that will not absorb it.^[1]

Asphalt Millings and Crushed Concrete are recycled options for the surface or the base. Millings pack into a firm, dark top that resists washboarding once warm weather sets them.^[4]

The Nebraska Department of Transportation calls for Crushed Rock for Base Course in Section 305 of its Standard Specifications for Highway Construction (2017). A highway base is a graded, compacted rock layer meant to carry trucks over the same kind of clay, and a home drive follows the same idea at smaller scale.^[5]

Fill, Topsoil and Raising a Grade

On occasionally flooded ground, raising the grade is often the first step for a shed pad, a patio or a garden. Fill Dirt is the material for bulk raising: it packs firm and has little organic matter to rot and settle. Spread it in thin layers and compact each one, since a thick, loose lift will settle unevenly for years.^[1]

Keep heavy clay fill out of spots near a foundation where water should drain away. Fill Sand passes water and suits backfill around pipes and behind walls, while Topsoil finishes the surface where grass or plants will grow.^[1]

A raised grade only helps if it sheds water to somewhere lower. Before adding fill, watch where water goes during a heavy rain, and make sure the new slope sends it away from buildings and neighbors rather than onto them.^[1]

Housing in 68102

ZIP 68102 has 6,251 housing units by the Census count. Detached single-family houses make up 2 percent of them, compared with 62 percent across Omaha.^[6]

The median home in the ZIP was built in 1953, older than the 1973 median across Omaha's 213,023 housing units. Owners occupy 16 percent of the occupied homes in 68102.^[6]

Downtown landscape work can mean planters, courtyards and small parking areas more than large yards. Raised planters filled with Garden Soil skip the native clay altogether and drain far better.^[6]

Old foundations and walls can make digging near downtown unpredictable. Expect buried brick, concrete and old utility lines, and have the lines located before any digging starts.^[6]

Beds and Drainage on Heavy Clay

Heavy silty clay is fertile but suffocates roots when it stays wet. Build garden beds up instead of digging down, and fill them with Garden Soil or Topsoil mixed with Compost. The root zone then sits above the wettest ground.^[1]

Keep water away from foundations. On a soil with very high shrink-swell, a wet strip along a wall swells and pushes, while a dry strip shrinks and pulls away. A sloped grade, gutters that empty well away from the house and a band of River Rock under the drip line keep moisture even.^[1]

Mulch beds with Brown Shredded Mulch, Black Shredded Mulch or Red Mulch after the April 18 median last freeze, once the soil warms. Mulch keeps clay from crusting in rain and from cracking open in a dry summer. Add a fall layer before the October 21 median first freeze to protect perennial roots.^[4]

For a soggy area that never dries, a French drain of Drain Rock around a perforated pipe, wrapped in fabric, carries water to a lower outlet. On group D soil, a drain needs a real exit, since the clay around it will not soak the water up.^[1]