Gravel, Landscape Rock and Soil Delivery in Denver, CO

Dry air, long cold

The NOAA normals station at Denver Water Dept, about 2 miles away, averages just 15.8 inches of precipitation a year but 40.7 inches of snowfall. Light, dry snow can pile up and then vanish under strong sun within a day or two, so surfaces here go from frozen to wet to dry over and over through winter.^[1]

The same station counts 150 days a year when the low drops to 32 F or below. Its median last spring freeze is April 30, and the median first fall freeze arrives on October 12. A gardener planting tender annuals before the end of April takes a real gamble, while gravel and stone work can carry on through most of the year as long as the ground is not frozen hard.^[1]

The ground at the center point of ZIP 80202 stands 5,190 feet above sea level.^[2]

Sunny, dry air and frequent wind pull moisture out of exposed soil quickly, which argues for mulch on every bed and a stone cover on any slope that would otherwise blow or wash. A layer of Wood Chips on a new bed, or Stone Dust Screenings packed firm on a utility path, keeps dust down until plants or foot traffic settle the surface.^[1]

Clay loam that swells and shrinks

The USDA survey maps the center point as Urban land-Altitude complex on 0 to 3 percent slopes. Paving and buildings account for 55 percent of the map unit, and Altitude soil makes up 20 percent. Its top mineral layer is a clay loam, rated well drained but placed in hydrologic group C, the class with slow infiltration.^[3]

Shrink-swell in the top 100 cm is moderate, at 5.1 percent. Clay loam with that rating gains volume when snowmelt soaks it and loses volume again in a dry spell. Over a few seasons, that movement cracks thin slabs and tilts loosely built paver patios. A gravel surface tolerates it far better, because loose stone simply settles back into place.^[3]

Slow infiltration also means water from a quick spring storm runs off rather than soaking in. Keep gutters and downspouts pointed at a bed of River Rock or a trench of Drain Rock that leads away from the foundation, so moisture does not collect against the clay beside the house.^[3]

Paving and buildings cover a little over half of the mapped unit, so the soil in a given yard may be imported fill rather than native Altitude clay loam. Before ordering, dig a test hole a spade deep. Firm, sticky brown clay means native ground. Loose, mixed material with brick or gravel in it means fill, which should come out of the footprint of any drive or patio and be replaced with packed Road Base.^[3]

Well drained and slow to soak are not a contradiction. The drainage class describes how quickly the profile sheds extra water over time, while the hydrologic group describes how fast rain enters the surface during a storm. For a project, that means water will not sit for weeks, yet a heavy burst will still run off before it soaks in.^[3]

Snow and the gravel driveway

A drive that sees a plow or a shovel all winter needs a surface that stays locked. Start with fabric over the clay, then pack Road Base in thin lifts until it rings under a hammer. A finish of 3/4" Crushed Stone or Driveway Gravel bonds with the base and resists being pushed into the snowbank.^[1],[3]

Set the plow blade or snowblower skid shoes slightly high, so they ride over the stone instead of scraping it. Each spring, rake displaced gravel back from the edges and top up thin spots. Where melting snow piles drain across the drive, a shallow crown and a stone-lined edge keep that water from softening the base.^[1]

Recycled options work here too. Crushed Concrete packs nearly as hard as Road Base for a work yard or side lot, and Asphalt Millings form a dark, firm surface that sheds snow quickly once the sun hits it.^[3]

Driveway repairs wait for thawed, dry ground. After the median last spring freeze of April 30 at the Denver Water Dept station, rake ruts level, spread fresh Driveway Gravel where the base shows through and pack it with a plate compactor. A small top-up each spring takes far less effort than rebuilding a drive that was left to break down.^[1]

Rock gardens and low-water beds

Little rain and strong sun make Denver a natural home for gravel gardens. Decomposed Granite paths and patios pack firm, drain well and blend with native plantings. River Rock in swales and dry creek beds handles the occasional downpour, and larger Riprap anchors a slope or a retaining edge.^[1],[2]

For planted beds, clay loam benefits from organic matter. Work Compost into the top layer, or build raised beds with Garden Soil, then cover the surface with Brown Shredded Mulch or Wood Chips. Mulch keeps the clay from crusting under summer sun and shields roots during the long run of freezing nights.^[1],[3]

Timing matters for anything living. With a median first fall freeze of October 12 at the Denver Water Dept station, fall planting should finish early enough for roots to settle. Spread Topsoil to level a new lawn area in late summer, and add fresh mulch after planting to hold soil warmth into the first cold nights.^[1]

River Rock or Decomposed Granite

Two materials carry most low-water landscapes, River Rock and Decomposed Granite, and they do different jobs. River Rock is smooth, washed stone that never packs down. It stays loose, drains at once and shows off its color, which makes it the right pick for dry creek beds, downspout outlets and borders around shrubs where nobody walks.^[1]

Decomposed Granite is the opposite: fine, gritty and full of small particles that bind when wetted and tamped. It makes a firm surface for walking, sitting or setting a bench. On clay loam, lay it over a packed base and a fabric layer, because repeated freezing and thawing will otherwise work it into the soil. Many yards use the pair together, with Decomposed Granite for paths and the patio and River Rock for edges and drainage lines.^[1],[3]

Homes and the state base spec

The Census counts 14,719 housing units in ZIP 80202, and only 2 percent are detached single-family houses. The median home in the ZIP was built in 2007. Owners live in 23 percent of the occupied homes there.^[4]

Denver as a whole has 359,581 housing units. Detached houses make up 40 percent of the city's housing, and the city's median build year is 1975.^[4]

The Colorado Department of Transportation describes the crushed layer under its pavements as Aggregate Base Course, Class 6, Section 304, in its Standard Specifications for Road and Bridge Construction 2025.^[5]