Los Angeles River
The Los Angeles River has its headwaters in the San Fernando Valley and runs 50 miles (80 km) through downtown Los Angeles down to Long Beach.
It has concrete banks which help prevent seepage and overflowing. Los Angeles receives rainfall of about 16 inches (400 mm) per year, which is moderate compared to other cities: so most of the time the Los Angeles River is either a dry concrete riverbed, or it has a few inches of water that is brackish, highly contaminated, and unsafe for drinking since the river runs through mostly industrial areas which dump waste into it. When dry, the riverbed is often used by bicyclists and as a location for Hollywood movie car chases. When it does rain the river can fill very quickly, move rapidly, and become dangerous for anyone who ventures near it. Sometimes it will be raining in the foothills and the mountains (which feeds the river) but not in the city. Work crews in the dry riverbed have been caught by surprise by a sudden wall of water carrying away everything in its path including their heavy trucks.
See also
