Река Питалума: описание, экология и проблемы бассейна.

River in California, United States

Located in southern Sonoma County, California, and a portion of northeastern Marin, the Petaluma River Watershed drains 146 square miles (378 km2). The watershed is approximately 19 mile (31 km) long and 13 mile (21 km) wide with the City of Petaluma near its center. At 2295 feet (700 m), Sonoma Mountain is the highest point in the watershed, and its western slopes drain to the Petaluma River by way of tributaries such as Lichau Creek, Lynch Creek, Washington Creek, and Adobe Creek. The lower 12 mile (19 km) of the Petaluma River flow through the Petaluma Marsh, the largest remaining salt marsh in San Pablo Bay. The marsh covers and is surrounded by approximately of reclaimed wetlands. Chinook salmon (Oncorhynchus tshawytscha) are seen in the main stem of the Petaluma River and The United Anglers of Casa Grande High School have seen chinook at the turning basin, near the Lynch Creek confluence. The high school students constructed a salmonid hatchery in 1993 and in 2002 74 Chinook salmon returned to spawn in the Adobe Creek tributary.

The marshes provide an important wildlife habitat and fish hatchery. However, since the onset of intensive immigration in the mid 1850s, the water quality has diminished, partly due to overgrazing and other agricultural uses. Pollutants present in the river include nitrates, phosphates, petroleum hydrocarbons, pesticides and sediment. Urban runoff, particularly from the City of Petaluma, adds heavy metals and hydrocarbons to the river. Starting about 1990, material steps were taken to mitigate the pollution. Because the Petaluma River is relatively well protected, most of the pollution comes from nearby storm drains. It is up to the people of Petaluma to keep the river clean. Because most of the length of the waterway is tidal and urban/suburban, there is a significant collection of tidally deposited debris along the banks. Despite the poor aesthetics including turbidity, the water quality is not particularly poor. It has been alleged that the greatest threat to the Petaluma River is the planned Dutra asphalt plant. The reported concerns involve the "loud noises it will create" that will scare away the birds and "throw off the entire ecosystem".

The following bridges span the Petaluma River moving upstream from San Pablo Bay through Petaluma: the Black Point Railroad Bridge (NWP), California State Route 37, Haystack Landing Bridge (NWP), U. S. 101, D Street, Washington Street, Lakeville Street, NWP, Payran Street, NWP, Oak Drive, Corona Road, Petaluma Boulevard North, and Rainsville Road. The longest highway span, the 4 lane Route 37 bridge, is 2183 feet (665 m) long and was built in 1958. The oldest public bridge, built in 1925, is a 114 feet (35 m) concrete triple span carrying two lanes of Petaluma Boulevard North. Removal and replacement of the U. S. Route 101 highway bridge over the river began in 2013. The existing bridge was an 866 feet long, twin reinforced concrete box girder bridge (with a pre cast I girder span over the river) that was built in 1955. It had two lanes of traffic in each direction, limited sight lines, and no shoulders. The new bridge is a 907 feet long, precast, post tensioned spliced concrete girder design with three lanes of traffic in each direction and standard shoulders. Construction completed in mid 2016.