- Phase 1 of the spillway widening project at Schafer Dam is nearly done
- Phase 2 construction of the concrete weir will start in fall 2021
- Project completion scheduled for 2024
In the 1960s, Tulare County Supervisor Dennis Townsend was working for the water master of the Tule River when the dam at Success Lake got its first big test.
“In 1968, we had the 100-year flood,” he said. “The water went over the spillway. There was flooding in East Porterville and downstream farmland.”
But starting in early 2024, a similar deluge would be contained because the spillway is being raised by 10 feet, increasing reservoir storage by a third.
The federally funded project will boost flood protection for Porterville and the downstream lands from a 50-year flood event to a 100-year flood event, according to the U.S. Army Corps of Engineers.
“By adding ten feet, it doubles the protection for the city of Porterville,” said David De Groot, the new water master for the Tule River Association, the water rights holders.
The spillway project – widening the spillway and adding a 10-foot concrete weir – will also help downstream irrigation districts manage their Tule River water supply and comply with the state’s groundwater sustainability law.
Flood protection, water management, new recreation and groundwater recharge assistance – all for $135 million.
California’s dam-building era is arguably over, but the Schafer Dam spillway project on the Tule River near Porterville is a good example of how more water storage at existing dams can be achieved.
Schafer Dam was authorized by Congress in 1944 to protect the city from flooding and was completed in 1961.
The dam created Success Lake, capturing snowmelt from the Tule River drainage of the Sierra Nevada. In spring and summer, water rights holders use the water behind the dam to irrigate 140,000 acres between the dam and the old Tulare Lakebed.
Originally named Success Dam, it was renamed Richard L. Schafer Dam two years ago in honor of the Tule River water master, now emeritus, who held that title for more than 50 years.
That’s who Townsend was working for when the deluge came.
Raising the spillway is an idea that has been around 30 years or more. In 1999, Congress authorized The Success Reservoir Enlargement Project, also known as The Tule River Spillway Enlargement Project. Storing more water for downstream use is also a goal of the project under the Water Resources Development Act of 1999.
In 2003, a ribbon cutting ceremony took place. But concerns about a potential earthquake causing the dam to slump halted progress until the Army Corps of Engineers ruled out a catastrophic collapse.
The new spillway and weir project will increase water storage at Success Lake to 110,291 acre-feet, up from 84,000 acre-feet.
Fun fact: a few years ago, a survey revealed that Success Lake is bigger than thought, causing the Army Corps to revise the capacity upward to 84,000 acre-feet.
The weir increases lake capacity by over 28,000 acre-feet. That works out to a cost of about $4,821 per acre-foot of additional storage as an up-front capital cost– a good value.
The bigger lake won’t fill every year, of course, but the extra water is expected to average 6,000 acre-feet per year, said Eric Limas, General Manager of Lower Tule River Irrigation District.
“It gives us more operational flexibility” in wet years, Limas said.
For example, in very wet years, flood water from Millerton Lake could be taken from the Friant-Kern Canal and used for groundwater recharge, allowing Tule River water rights holders to store more water at Success Lake to be brought down later, he said.
Of course, “we’ll have to see how the Corps wants to operate it,” he said. The Army Corps of Engineers owns and operates Schafer Dam, so it decides when to release water.
A larger lake also boosts the opportunity to shunt water into recharge basins over more weeks in spring, Limas said. The water has been factored into the Groundwater Sustainability Plan of the Lower Tule River ID Groundwater Sustainability Agency, to help meet the goals of the Sustainable Groundwater Management Act of 2014.
Despite the regional importance of the spillway project, so far it has a low profile. In part because no groundbreaking ceremony took place due to the pandemic, and construction work to date is not easily visible from main roads. That is just fine with the local sponsors who include the County of Tulare, Kings County, the City of Porterville and a number of local water districts.
Lower Tule River Irrigation District is the lead agency for the locals sponsors.
One of the local sponsors described the dam raise as the most valuable water supply project in several decades, and almost no one is paying attention….and the locals water agencies are just fine with that. "No attention, no opposition, good cooperation" is the theme of the project.
The Army Corps of Engineers is in charge of construction at the spillway, which is being done in two phases.
Phase 1 involves widening the earthen spillway and relocating the road. In total, the spillway was widened more than 100 feet which literally moved the side of a mountain.
Phase 1 construction began last summer and finishes next month.
The dam has floodgates to release water downstream. The spillway is used if the lake is full and there’s more water coming in than can be let out.
Meanwhile, Phase 2 of building a 10-foot high concrete weir starts this fall. It’ll be an ogee weir, meaning that it’s rounded to create more room for spill over a shorter horizontal distance.
Bid specifications for Phase 2 will be released soon and the winning bid will be chosen in August or September.
The non-federal sponsors are responsible for approving environmental documents, purchasing real estate in new lake footprint, relocating power poles, wells, fences, houses and many other small details.
They are the fiscal agent and keep all the accounts. Local expenditures will be reimbursed later by the federal government.
Townsend credits “a lot of effort by Kevin McCarthy” – a Republican congressman from Bakersfield – for getting federal funding for the project.
Schafer Dam is in McCarthy’s district, and he was Majority Leader in the House of Representatives in 2018 when Congress approved full funding for the Success Lake project.
The pictures below show the local sponsors taking a tour of the Phase One project work last month.