Abstract: A filtering device and method is provided for filtering debris from liquid flowing over a surface. The device includes a flexible, liquid-permeable elongated body possessing a plurality of faces including a planar bottom face configured to rest on the surface. The liquid-permeable elongated body is formed of a plurality of compressed fibers and an adhesive bonding together the fibers. The device may be arranged on the ground on a construction site to inhibit loose debris from being washed away by rainwater into storm drains and nearby bodies of liquid.