Hydrogeology of The Kern River EarthCache

Hydrogeology of the Kern River

Earthcache lesson adapted from the San Joaquin Valley Geological Society.

•In the old days, before Bakersfield became a major city, the Kern River flowed south through now-vanished swamps that covered much of the area that the city occupies today. From these swamps, the river continued southward to Arvin, and finally flowed into Buena Vista Lake, which in those days covered thousands of acres. The lake overflowed regularly and sent volumes of water down the San Joaquin River, but canals have removed much of the river's might and no overflow has left the lake now for many decades.

•The river in the 1850s flowed in south-trending channel on the east side of the valley, but a flood in 1862 cut a southwesterly channel several miles to the west, pretty much along the route of the modern Old River Road. Another flood around 1869 removed snags and debris and moved the channel to its present location. In the meantime, the Bakersfield swamps were drained and filled in, enabling settlers to move into the area covered today by downtown Bakersfield.

•Floods plagued Bakersfield for many years as snowmelt regularly swelled the Kern River to raging torrent. This continued until the 1950s when the Isabella Dam and Reservoir were constructed to help regulate the river flow. In fact, the dam saved Bakersfield from flooding in 1966 when some 598,400 gallons of water per second rushed down the Kern River Canyon, nearly bringing the level of Lake Isabella up to the spillway.

•Today, the river encounters its first diversion into a canal when it first exits out of Kern River Canyon, and it encounters another diversion when it reaches the east side of Bakersfield near Hart Park. Just west of the park is where the river flow is measured by the water agencies, and the flow at this point determines what water allocations are allowed to flow down canals to farms throughout the valley.

•The first two of seven diversion weirs in town, the Bearsdley and Rocky Point weirs, are visible from Panorama Bluffs in northeast Bakersfield. From there, canal water travels north and south to irrigate farm fields. In total, the river is diverted into seven canals that run through town before what remains of the water finally flows into the remnants of Buena Vista Lake, a shadow of its former self.

•The river provides up to 700,000 acre-feet of water each year, which represents the same volume as 700,000 football fields covered by water 1 foot deep. In addition, Kern County receives another 400,000 acre-feet annually from the Central Valley Project, represented by the Friant-Kern Canal, and another 1 million acre-feet from the California Aqueduct. However, water supplies from these aqueducts are cut in half some years when droughts deliver insufficent rain to the mountains to replenish the streams.

•Interestingly, 80 percent of the drinking water used in Bakersfield is supplied from wells. Less than 20% comes from the river, most of the river water being used to irrigate thirsty farm fields.

•Up until the 1940s and 1950s, there were many shade trees along the Kern River, but diversion of water into canals for farm irrigation dried up the river banks and killed off most of the trees. For many years, the policy was to meet the irrigation needs first, and the river bed received only what was left over, which in drought years was nothing. However, as homes have grown up along the river banks, the city has found a desire to keep water in the river bed year round for recreation and to recharge the water table. Thus, water policy today is changing, and the needs of the river increasingly are being put before those of agriculture. This has led to considerable controversy, and many compromises will need to be made in future years to satisfy the needs of both farms and homeowners.

Log this earthcache:

Sources:

1) http://www.sjvgeology.org/geology/groundwater/kernriver.html

2) http://www.sjvgeology.org/geology/groundwater/index.html