What Is River Rock?
River rock is a type of naturally smooth, rounded stone that has been shaped by water flow over time. It is prized in landscaping for its attractive, organic appearance and comes in various colors including tan, brown, gray, white, and multi-colored blends. River rock is widely used for garden beds, pathways, dry creek beds, drainage areas, and decorative borders.
Unlike angular crushed stone, river rock's smooth surface makes it comfortable to walk on and less likely to damage plants or irrigation lines. Its rounded shape also provides excellent drainage, making it ideal for areas that need to manage water runoff.
River Rock Calculation Formulas
River Rock Coverage by Size
| Rock Size | Recommended Depth | Coverage per Ton |
|---|---|---|
| Pea Gravel (3/8") | 2-3 inches | 70-80 sq ft at 2" |
| Small (1-3") | 3-4 inches | 50-60 sq ft at 3" |
| Medium (3-5") | 4-6 inches | 40-50 sq ft at 4" |
| Large (5-8") | 6-8 inches | 25-35 sq ft at 6" |
Installation Tips
- Always lay landscape fabric beneath river rock to prevent weed growth and keep stones from sinking into the soil.
- Edge the area with metal, plastic, or stone edging to keep rocks contained.
- For walkways, compact a base layer of crushed gravel before adding river rock on top.
- A minimum depth of 2 inches is needed for small pea gravel; larger rocks need proportionally deeper beds.
- Order 5-10% extra material to account for settling and uneven ground.
Frequently Asked Questions
How deep should river rock be for landscaping?
For most landscaping applications, 2-4 inches is ideal for small to medium river rock. Larger decorative stones (5 inches and up) need 4-6 inches of depth for full coverage and stability.
How many tons of river rock do I need for 100 square feet?
At a 3-inch depth, 100 square feet requires about 25 cubic feet (0.93 cubic yards) of river rock, which weighs approximately 1.25 tons for medium-sized stones.
Is river rock good for drainage?
Yes, river rock is excellent for drainage. Its rounded shape creates natural voids between stones that allow water to flow through easily. It is commonly used in French drains, dry wells, and around foundation perimeters to direct water away from structures.