Lake McClure
Sierra Sun Times file photo
February 20, 2017 - Currently Lake McClure is slightly above 90 percent of its capacity and 15 feet below the reservoir’s maximum storage level. As is normal, water is continuing to be released from the reservoir’s primary outlet through New Exchequer Power House at the base of the dam under direction of the U.S. Army Corps of Engineers. Merced Irrigation District (MID) owns and operates New Exchequer Dam on the Merced River, which creates Lake McClure.
Contrary to information provided in a news report, there were no “levee breeches” along the Merced River on Thursday night. Water overflowing from a private ditch lead to a temporary road closure on Merced Falls Road near Snelling.
Lake McClure is a multi-purpose reservoir, providing flood protection, water storage and recreation. It has a capacity of 1 million acre feet and is located in the foothills of Mariposa County.
As is normal when Lake McClure exceeds approximately 67 percent of its capacity during flood-control months, the U.S. Army Corps of Engineers directs MID’s water releases from the reservoir. These releases are being made to provide space for storm runoff reaching the reservoir. So far, 2017 is the wettest year on record in terms of both snowpack and precipitation in the Merced River watershed. Water releases have continued to be made since mid-January from New Exchequer Dam through the direction of the U.S. Army Corps of Engineers.
The average inflow to Lake McClure over the past 24 hours has been approximately 12,500 cubic feet per second (CFS). MID is currently releasing flows of up to 7,000 CFS through MID’s primary outlet at the base of New Exchequer Dam.
Lake McClure’s primary release system for water is through the hydroelectric project at the base of New Exchequer Dam. It also has two emergency spillways if Lake McClure exceeds operational limits: a gated spillway is able to provide controlled releases if needed. A second ungated spillway could also be used for emergency releases.
Additionally, MID remains in daily contact with the local Office of Emergency Services. MID expects to continue releasing high outflows of water downstream of the reservoir for several months to accommodate flows of melting snow and future precipitation.
At various points along the Merced River, privately owned and operated diversion ditches are maintained by landowners with riparian water rights on the river. On Thursday night flows in the river overtopped one of the private ditch gates near the Snelling area. That water eventually made its way to Merced Falls Road east of the town of Snelling. Although these are private ditches and outside the jurisdiction or control of Merced Irrigation District, MID water crews immediately responded to an OES request and assisted to divert water back to the Merced River with the approval of the landowner. Overnight Thursday and well into Friday, MID continued to support local efforts to shore up and plug areas of concerns along the private ditches in areas at which they diverge from the main stem of the Merced River.
Source: MID
