Gravel, Base and Soil Delivery in College Station, TX

Sandy on top, slow and swelling below

The center point of ZIP 77840 falls in Boonville-Urban land complex, 0 to 3 percent slopes, on the USDA soil survey. The Boonville series makes up 50 percent of that map unit, and urban land, paved or built over, accounts for 40 percent.^[1]

The top mineral layer of Boonville is fine sandy loam, which looks and digs like an easy soil. The other ratings point the other way. The survey calls it somewhat poorly drained and puts it in hydrologic group D, very slow infiltration and high runoff. Shrink-swell in the top 100 cm rates high, at 7.5 percent.^[1]

A sandy surface with slow drainage and a high swell rating points to dense clay a short way down. Rain soaks into the sandy layer, stalls on the clay, and keeps the ground soggy after a storm. The clay swells as it wets and shrinks in a dry spell, enough to crack slabs and shift edging.^[1]

Digging on this ground can show the change clearly: an easy layer of sandy soil, then a stiff, sticky clay that holds water in the bottom of the hole. That clay is the layer to keep dry and covered under any base.^[1]

The USGS state geologic map shows the Yegua Formation at the center point. That Eocene unit is a mix of claystone, sandstone, limestone, lignite and volcanic material, which fits a clay-rich subsoil.^[2]

Plenty of rain and a short cold snap

The nearest NOAA normals station, College STN, TX, is about 3 miles away. It averages 41.8 inches of precipitation a year. The low there reaches 32 F or colder on 16 days in an average year.^[3]

The median last spring freeze at College STN is February 27, and the median first fall freeze is November 30. Freezing nights are few, so frost heave is a minor concern. Water, and the clay's reaction to it, is the main design problem.^[3]

A yearly total of 41.8 inches on a group D soil means much of each heavy storm runs off. Bare soil washes, low spots pond, and gravel laid without a crown turns into puddles. Every project here should start with a plan for where the runoff will go.^[1],[3]

Warm, wet weather speeds the breakdown of wood mulch and the growth of weeds through bare gravel. A fabric layer under decorative stone and a thick layer of mulch in beds both cut down on weeding.^[3]

Crushed Concrete or Road Base for a parking lot

In a ZIP full of apartments and rentals, gravel parking areas are a frequent job, and the base material is the first decision. Road Base, crushed rock with fines, compacts into a tight, hard layer that sheds water well. Crushed Concrete, made from recycled concrete, packs nearly as firm and drains a little more freely through its open structure.^[1],[4]

On this soil the preparation matters more than the choice. Dig past the sandy topsoil, compact the floor, and lay a woven geotextile so the clay below cannot pump up into the stone. Build the base in thin, wetted lifts. Finish with Driveway Gravel, 3/4" Crushed Stone or Asphalt Millings, and crown the surface so rain runs to the edges.^[1]

The Texas Department of Transportation names Flexible Base, Item 247, in its Standard Specifications for Construction and Maintenance of Highways, Streets, and Bridges (2024). That item defines the stone course the state lays under its paved roads.^[5]

A private lot need not match a highway item. What carries over is the method: graded, angular stone, compacted in layers, with water steered off the subgrade. Wheel stops and a firm edge keep a gravel lot tidy under daily traffic.^[1]

Lot edges take the most abuse. Where cars turn off pavement onto gravel, an extra lift of base and a border of larger stone such as #4 Crushed Stone keeps the edge from crumbling into ruts.^[1]

Draining slow ground

Water perched above the clay can sit in a lawn for days. A French drain cuts it off: a fabric-lined trench, a perforated pipe and Drain Rock or #57 Crushed Stone around it, running with a steady fall to a street drain or a lower area. On group D soil, the outlet is the part that makes it work.^[1]

A dry well rarely empties in somewhat poorly drained ground with clay below, so pipe the water out instead. Splash pads of River Rock under downspouts stop the stream from digging, and a shallow swale lined with #57 Crushed Stone can carry roof water across a yard to the street.^[1]

Foundations on high shrink-swell soil suffer when water pools at the walls in one season and the soil dries out in the next. Grade the soil away from the house, keep gutters clear, and move downspout water well out from the slab.^[1]

Lawns, beds and paths

Fine sandy loam on top is easy to plant, but the slow drainage below can drown roots in a wet spell. Raised beds filled with Garden Soil keep plants above the soggy layer. Compost worked into the sandy surface helps it hold water through hot, dry weeks without staying wet.^[1]

Mulch protects the soil from heavy rain and summer sun. Brown Shredded Mulch, Black Shredded Mulch and Red Mulch stay in place on beds, and Wood Chips suit larger areas under trees. Refresh mulch after the February 27 median last freeze and again before the November 30 median first freeze.^[3]

Paths stay usable in wet weather when they are built up and drained. Walkway Gravel or Stone Dust Screenings over compacted Road Base on fabric makes a firm walk, and a slight crown keeps puddles off it. Topsoil patches thin lawn areas once the ground is dry enough to work.^[1]

Volleyball courts and play areas are popular in a community like this one. Playground Sand or Mason Sand over a drainage layer of #57 Crushed Stone on fabric keeps the surface from turning to mud after a storm.^[3]

Shade under mature trees often defeats grass. A bed of Wood Chips, or a small seating area of Pea Gravel over fabric, gives those spots a tidy finish without a fight to grow turf.^[1]

Housing in ZIP 77840

The Census counts 25,203 housing units in ZIP 77840. Detached single-family houses make up 17 percent of them, and owners live in 10 percent of the occupied homes. The median home in the ZIP was built in 1990.^[4]

College Station as a whole has 51,494 housing units, by the same Census count. Detached houses make up 42 percent citywide, and the city's median year built is 1999.^[4]

Rentals and apartment buildings dominate the ZIP, so property managers and landlords place many of the orders: base and gravel for parking, mulch for common areas, and sand for courts and play spaces. Gravel Valet handles loads sized for each.^[4]