Post by spacecowboy2006 on Mar 15, 2017 19:48:29 GMT
When Alameda Creek flooded in December of 1955 it was reminiscent of when the stream was full from bank to bank naturally.
Flood waters inundated farms, roads, and homes the day after the flood crested. Heavy rain filled Alameda Creek to overflowing and the floodwaters spilled out over the flatlands of Fremont and Union City. Historical and geological records show that the creek has probably flooded like this every 50 to 100 years for many thousands of years.
Alameda Creek is the largest stream in the county, draining all of Livermore Valley through Niles Canyon. Before urban development, each flood laid down another layer of sediment on the flatlands of the Fremont area. Indeed, the flatlands were built by the creek. The soil here consists of layer upon layer of sand, silt, clay, and gravel deposited by the floodwaters of Alameda Creek. These deposits form an alluvial fan, a gently sloping fan-shaped deposit, radiating from the outlet of Alameda Creek near Niles.
With new homes and businesses locating on the Alameda Creek fan, it was no longer desireable to allow nature to take its course. Prompted by the flood of 1955 and a similar flood in 1958, the residents voted to create the Alameda County Flood Control District and a flood control channel was built to carry floodwaters out to the bay. This channel, about 200 feet wide, 10 miles long, and bordered by 20-foot high levees, holds much more water than the original creek bed. As of the spring of 1997, it has not yet been overtopped by flooding. The natural cycle of flooding and alluvial fan construction has been suspended for now.
Maps of the extent of the 1955 flood waters, along with flood height records back to 1919, are published on U.S. Geological Survey Hydrologic Atlas HA-54 by L.E. Young.
links include images: explore.museumca.org/creeks/z-fremontflood.html
www.google.com/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=alameda+creek+flood+1955&*
Flood waters inundated farms, roads, and homes the day after the flood crested. Heavy rain filled Alameda Creek to overflowing and the floodwaters spilled out over the flatlands of Fremont and Union City. Historical and geological records show that the creek has probably flooded like this every 50 to 100 years for many thousands of years.
Alameda Creek is the largest stream in the county, draining all of Livermore Valley through Niles Canyon. Before urban development, each flood laid down another layer of sediment on the flatlands of the Fremont area. Indeed, the flatlands were built by the creek. The soil here consists of layer upon layer of sand, silt, clay, and gravel deposited by the floodwaters of Alameda Creek. These deposits form an alluvial fan, a gently sloping fan-shaped deposit, radiating from the outlet of Alameda Creek near Niles.
With new homes and businesses locating on the Alameda Creek fan, it was no longer desireable to allow nature to take its course. Prompted by the flood of 1955 and a similar flood in 1958, the residents voted to create the Alameda County Flood Control District and a flood control channel was built to carry floodwaters out to the bay. This channel, about 200 feet wide, 10 miles long, and bordered by 20-foot high levees, holds much more water than the original creek bed. As of the spring of 1997, it has not yet been overtopped by flooding. The natural cycle of flooding and alluvial fan construction has been suspended for now.
Maps of the extent of the 1955 flood waters, along with flood height records back to 1919, are published on U.S. Geological Survey Hydrologic Atlas HA-54 by L.E. Young.
links include images: explore.museumca.org/creeks/z-fremontflood.html
www.google.com/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=alameda+creek+flood+1955&*