lower river. In addition, several major wastewater treatment plants discharge effluent to the river, the largest being the Los Coyotes plant, which has an output of 30 million gallons (110,000 m3) per day. A total of 598 businesses, manufacturers and other parties are licensed to discharge storm water into the San Gabriel River, and more than 100 storm drains empty directly into the river. The upper reaches of the river, although undeveloped, are subjected to heavy recreational use and are impacted by trash, debris, fecal coliforms and heavy metals. The U.S. Forest Service removes about four hundred 32-gallon bags of trash from the East Fork each weekend. A 2007 study found that Coyote Creek, the main tributary of the lower San Gabriel River, exhibited "acute and chronic toxicity" from pesticides and industrial chemicals, while toxicity levels in the main stem San Gabriel River, Walnut Creek and San Jose Creek were "significantly reduced" from 1995 levels due to improved water treatment systems. The Alamitos and Haynes generating stations are located on the lower San Gabriel River and discharge their cooling water into the river. This has had adverse impacts on habitat surrounding the river's estuary. A considerable portion of the groundwater in the San Gabriel River watershed is also polluted, mostly from industrial chemicals. The San Gabriel Valley has four Superfund sites where water is being extracted for treatment before being pumped back into the ground. Crossings From mouth to source (year built in parentheses): Marina Drive (1963) - Pacific Coast Highway (1931) Second Street - twin bridges (1964) - East 7th Street - twin bridges (1941, 1959) College Park Drive (1964) Southbound Interstate 605 ramp to northbound Interstate 405 (1966) - San Diego Freeway (1964) Southbound Interstate 405 ramp to northbound Interstate 605 (1966) East Willow Street (1962) East Spring Street (1952) East Wardlow Road (1963) San Gabriel River Bicycle Path [bike bridge] Carson Street - twin bridges (1971) Del Amo Boulevard (1966) South Street (1952) 183rd Street (1972) Artesia Boulevard (1941) Railroad (West Santa Ana Branch, disused) - Artesia Freeway (1968) [Pedestrian Bridge] Alondra Boulevard (1952) Rosecrans Avenue (1951) Foster Road [Pedestrian Bridge] Eastbound Interstate 105 ramps to Interstate 605 (1987) - Glenn Anderson Freeway and Metro Green Line (1987) Interstate 605 ramps to westbound Interstate 105 (1987) Imperial Highway (1952) Railroad (Union Pacific) Firestone Boulevard (1934) Florence Avenue (1951) - Santa Ana Freeway (1953) Telegraph Road (1937) Railroad