Saltwater intrusion from the ocean has occurred in the southern Oxnard Plain due to the overdraft of groundwater. The Santa Clara Irrigating Company was formed in 1870 and drew water from the Santa Clara River, using a ditch system to irrigate the grain crops. Early settlers began pumping soon afterwards to support farming activities with what at first was a more reliable source. In the modern era, much of the groundwater has been rendered useless for agricultural or potable uses by salt-water intrusion. Unlike coastal Los Angeles and Orange County, Ventura County has no barrier in place to prevent the ocean water from intruding into the inland aquifers.