Bill calls for look at raising dam spillway, increasing lake capacity at McClure

The Merced Irrigation District is backing a bill in Congress that would allow consideration of an increase in the water capacity of Lake McClure, possibly providing enough power to serve 1,700 homes.

That would be done by raising its spillway, the structure that controls the flow of water from the New Exchequer Dam, by up to 10 feet.

The project would cost $40 million and use only MID funds.

However, the New Exchequer Dam Spillway Modification Project has sparked opposition from conservationists who are concerned with dam safety and possible flooding of trails and land.

MID officials contend the project would be beneficial.

John Sweigard, general manager, said the bill would allow MID to increase the height of the existing spillway gates and the ungated spillway by up to 10 feet, which would in turn increase the capacity of Lake McClure. Mike Jensen, public information officer for MID, said the spillways are a half mile from the dam and the project would expand the reservoir about 1,700 feet upriver from the existing terminus upstream of Bagby Recreation Area.

Lake McClure sits on the Merced River and has a capacity of 1.02 million acre-feet of water and an average annual reservoir inflow of 975,000 acre-feet. An acre-foot of water contains about 326,000 gallons.

The proposed project would allow MID to store up to an additional 70,000 acre-feet of water, Jensen said. According to the bill's language, the additional water would be stored between May 1 and July 31 during wet years, which are expected to be once every three years or so, Jensen said.

"We would be able to use that for all kinds of uses: irrigation, hydroelectric generation and groundwater recharge," Jensen said. "There are also recreational benefits from additional water."

The bill, House Resolution 869, was introduced by Rep. Jeff Denham, R-Atwater, to the U.S. House of Representatives in March. The bill has been referred to the Subcommittee on National Parks, Forests and Public Lands.

The bill also has bipartisan support from Rep. Dennis Cardoza, D-Merced, and Rep. Jim Costa, D-Fresno, Jensen said.

Merced County Supervisor John Pedrozo said the project would benefit the whole economy, community and keep farmers happy. "We are always concerned (with water). We don't think about it this year because of the abundance of rainfall, but I've been through a drought in 1977 when we had no water to irrigate and we were short of water," he recalled.

He said raising the spillway would be a plus. "Anytime you can expand to hold more water, it's definitely a benefit," he said. "Since we can't build a new dam in California, we have to look at other avenues to make this thing work."

Agriculture produces hundreds of millions of dollars for the local economy, he said. "We need to focus on that," said Pedrozo, who used to farm alfalfa and silage corn and raises dairy heifers. "There are also all kinds of recreational use up there. Water is a necessity for agriculture."

Concerns raised

However, resistance to the bill comes from opponents who maintain that there are undisclosed environmental and social impacts that haven't been studied by MID.

Michael Martin, director of the Merced River Conservation Committee based in Mariposa, said the move would encroach on the National Wild and Scenic Rivers system.

About 122 miles of the Merced River is designated as a Wild and Scenic River above elevation 867 feet. The National Wild and Scenic Rivers System was created by Congress in 1968. The act is intended to safeguard the special character of designated rivers, while recognizing the potential for their appropriate use and development, according to the National Wild and Scenic Rivers website.

Sweigard said the Wild and Scenic Rivers Act is designed to protect rivers from development. He said there would be minimal impacts with this project. "At low flow the river is shallow. At really high flows, the water can get very deep. It can get 10 feet deeper from low flow to high flow or more than 10 feet," Sweigard explained.

For example, during the week of March 15, the flow increased enough in all stretches of the Merced River in the range of 10 feet, he said.

Water levels wouldn't change based on what MID would be doing, but he said MID would like to do what Mother Nature has done for shorter periods of time. "We're doing the same thing in a controlled manner," Sweigard said.

Jensen said the Federal Energy Regulatory Commission boundary for MID's hydroelectric project on the Merced River was established in the 1960s. FERC is the independent agency that regulates the interstate transmission of electricity, natural gas, and oil. When the river's Wild and Scenic designation was later made in the 1990s, it overlapped the existing FERC boundary.

"This placed Wild and Scenic River Act restrictions on MID's project," Jensen said.

Martin said the project would damage the trail and flood government and private land. "It probably will impact salamander habitats and flood at least two of the campgrounds," he added. "The last reason we are concerned about it is, while it's claimed by MID it's going to improve their flood control, it would appear to us just the opposite."

Martin said raising the level of the lake to 10 feet higher than its current capacity would limit the amount of flood space. He said flood space allows for rainwater and snowmelt in the spring to collect so that they don't flood the Merced and San Joaquin rivers. "We would like to know about the potential flood risks as well as what are the dam safety issues," he added.

In any case, FERC would have to review the project.

"If the legislation were to pass, it would allow for consideration of the project," Jensen stressed. "Right now, we can't even ask if it can be done."

Reporter Ameera Butt can be reached at (209) 385-2477 or abutt@mercedsun-star.com.