Northwest Environmental Defense Center, et al. v. Brown, et al., 617 F.3d 1176 (9th Cir. 2010)

(collected runoff from logging operations (i.e., mud and sediment that washes off logging roads) into forests and rivers is a point source discharge of stormwater associated with industrial activity requiring an NPDES permit under the CWA; the runoff is collected in a system of ditches, culverts and channels which is subsequently discharged into streams and rivers).