Watershed protection activities in the San Gabriel and Los Angeles River watersheds shall be consistent with the San Gabriel and Los Angeles River Watershed and Open Space Plan as adopted by the San Gabriel and Lower Los Angeles Rivers and Mountains Conservancy and the Santa Monica Mountains Conservancy. Notwithstanding any other provision of law, this plan shall be implemented pursuant to Division 23 (commencing with Section 33000) of the Public Resources Code in the watershed of the Los Angeles River upstream of the northernmost boundary of the City of Vernon and pursuant to Division 22.8 (commencing with Section 32600) of the Public Resources Code in the San Gabriel River and in the lower Los Angeles River watershed.