Gravel, Stone and Soil Delivery in Ada, OK

Old river terraces with stone already in them

The geologic map at the center point of ZIP 74820 shows Terrace Deposits of Pleistocene age. Terraces are old floodplains left high and dry as streams cut lower. The unit lists coarse alluvium, fine alluvium and volcanic material among its sediments.^[1]

The USDA soil survey maps Chigley gravelly sandy loam, 1 to 5 percent slopes, at that point. Chigley makes up 85 percent of the map unit. The word gravelly means pebbles are mixed into the top layer, which fits ground built on old stream terraces.^[2]

Gravelly sandy loam digs harder than plain loam, and a shovel will hit stones. Gravelly ground drains better near the surface than finer soil does. For a bed, those pebbles mean you will want to add fine soil rather than dig in place.^[2]

The ground at the center point rises about 1,000 feet above sea level, on a gentle slope of 1 to 5 percent. That fall is enough to move rain off a drive if the surface is shaped for it.^[2],[3]

Slow infiltration under a fast top

Chigley is rated moderately well drained, but its hydrologic group is C, a class where water soaks in slowly. The two ratings fit together. The sandy, gravelly top lets rain in, then a tighter layer lower down slows it, and water can perch on that layer after a long rain.^[2]

Shrink-swell in the top 100 cm is moderate, at 4.5 percent linear extensibility. The soil swells some when wet and shrinks some when dry. A compacted stone base spreads that movement so a drive or a slab stays even.^[2]

The survey places lithic bedrock at about 60 inches below the surface. Lithic means hard rock that a hand tool will not cut. Most driveways and patios never reach that depth, but a deep post hole, a dry well or a deep footing could. Water that soaks down can also spread along the top of that rock instead of sinking further.^[2]

Rain, snow and freeze at the Ada gauge

The NOAA normals station at Ada, OK, about 5 miles away, averages 41.5 inches of precipitation a year. Spring storms in this part of the state can drop a lot of rain at once, so plan for heavy bursts as well as the yearly total.^[4]

Snowfall at the gauge averages 4.1 inches a year. A light snow melts off a dark gravel drive quickly, and a crowned surface lets the melt run to the sides instead of soaking the base.^[4]

Ada records 72 days a year when the low reaches 32 F or colder. Freezing nights followed by mild days work water in and out of any fines in a drive, so a base with good drainage lasts longer.^[4]

The median last spring freeze at the gauge is April 2. The median first fall freeze is November 4. Plant beds after the April date, and spread a fresh layer of mulch before the November one to shield roots.^[4]

A drive that sheds water on a gentle slope

Start by setting the grade. On a 1 to 5 percent slope, run the drive across the fall where you can, or add a crown, so water leaves the surface quickly instead of running down its length. Water racing down a long straight drive cuts ruts in loose stone.^[2]

Scrape off the top soil to firm ground. Gravelly sandy loam often makes a fair subgrade once it is compacted. Lay a fabric where the ground stays wet after a rain, a sign of the slow group C layer below.^[2]

Place Road Base in layers and roll each one. Top it with Driveway Gravel or 3/4" Crushed Stone. Where a culvert or a ditch crosses the drive, armor the inlet and outlet with Riprap so storm runoff does not wash the bank.^[4]

For a heavier rural drive that sees trucks and trailers, 1-1/2" Crushed Gravel under the base adds strength. Railroad Ballast, with its large angular pieces, can stabilize a soft entrance or a steep culvert crossing.^[2]

Paths and pads on pebbly ground

Walkways and parking pads on gravelly sandy loam need less digging than they would on soft clay. The pebbles in the Chigley top layer give the subgrade some bite once it is rolled. Strip the grass and roots, level the ground and run a plate compactor over it before any stone goes down.^[2]

For a garden path, Walkway Gravel or #89 Crushed Stone packs into a firm tread that a wheelbarrow can cross. Pea Gravel feels softer underfoot but rolls on a slope, so save it for flat runs. Decomposed Granite gives a smooth, tan surface that sets up hard when wetted and rolled.^[2]

A pad for a trailer, a shed or a tank needs more strength. Lay Road Base or Crushed Concrete in compacted lifts, then add a top of 3/4" Crushed Stone. Extend the base a little past the footprint of whatever sits on it, so the edges do not crumble under a jack or a wheel. A pad on the downhill side of a lot should have its own small swale so water from above runs around it, not under it.^[2]

Asphalt Millings suit a work yard or a long farm lane. They take less work to keep tidy than loose stone because the old binder knits the pieces together on hot days. Spread them over a firm base and roll them while the weather is warm. Edge a millings lane with larger stone so the outer strip does not ravel when tires drift onto it.^[2]

Beds, drains and homes in ZIP 74820

Garden beds on gravelly ground need fine soil added. Mix Garden Soil or Topsoil with Compost and build the bed up rather than trying to sift out the pebbles. Brown Shredded Mulch or Wood Chips on top keeps the soil cool and damp.^[2]

Where rain perches on the tighter layer, a French drain of Drain Rock or #57 Crushed Stone leads it away from a foundation. Pea Gravel and River Rock make good surfaces for a dry creek that carries roof runoff across a yard.^[2]

The Census counts 14,552 housing units in ZIP 74820, compared with 8,119 inside the City of Ada. Detached single-family houses make up 76 percent of homes in the ZIP and 70 percent in the city.^[5]

Homes in the ZIP have a median build year of 1977, and the city median is 1969. Owners occupy 63 percent of occupied homes in ZIP 74820. Many older drives in a housing stock of that age have thinned out and need a new top layer.^[5]

The Oklahoma Department of Transportation publishes Aggregate Base, Type A, Section 303, in its Standard Specifications for Highway Construction (2019).^[6]