A liner assembly (222A) for a sand trap (10) having a perimeter (12) that defines a cavity (13) and a substrate (18) within the cavity (13) includes a first layer (230A) and a second layer (232A). The first layer (230A) is positioned on the substrate (18) and can be formed from a substantially water-permeable material. The second layer (232A) can be formed from a substantially water-impermeable material and is applied to the first layer (230A). The second layer (232A) can be applied to the first layer (230A) as a liquid, such as a polyurea material. In one embodiment, at least one of the layers (230A, 232A) extends within the substrate (18) at least partially outside the perimeter (12) of the sand trap (10). The second layer (232A) can include an aggregate material that is integrally formed as part of the second layer (232A).