The Monticello Dam spillway in Northern California was turned on for the first time on 4 February since 2019 due to high water levels in the manmade Lake Berryessa, according to the Solano County Water Agency.

Its release system is known as a “glory-hole” style, as a result of the plughole-like effect as the water flows out.

Officials say this system was used because the dam was too narrow for a traditional release spillway.