A 2000-page environmental impact report has been released detailing the steps required for the removal of the Matilija dam in California, US.
The dam removal – a US$110M project – requires tearing down the massive concrete dam across Matilija Creek and handling the 4.6Mm3 of sediment that have built up behind the wall since the dam was built in 1947. According to the plan, workers would dredge about 1.5Mm3 of fine sediment from the shallow lake north of the dam, mix the sand with water to a gravy-like consistency and pipe the slurry south for spreading on 47.8ha near Highway 150 and the Ventura river.
The dam, 2.4m thick at the top and 10.7m at the base, would be blasted and the concrete trucked to a recycler. Federal funds are expected to cover 65% of the US$110M cost and local or state funds will make up the remaining 35%.