30/11/2017 · Understanding Washed Gravel, Drainage Gravel, and River Rock. Written by Builders Sand Gravel Inc. on November 30, 2017. Posted in Blog. Most gravel has a rough, textured look. These rocks are used for long driveways, roads, and other heavy duty appliions. Washed gravel, on the other hand, has the appearance of smooth river rocks, making it ideal for more upscale properties .