Flows on the Stanislaus River will be lowered over the Fourth of July weekend. Recently, the Stanislaus has been running high and cold at 2,000 cubic feet per second (cfs).
The Bureau of Reclamation (BOR), the federal agency that operates New Melones Dam, has made adjustments to their operations plan, where their operating permit stated that they could not store water after June 30, which would have resulted in outflows from New Melones being equal to the inflows.
According to Oakdale Irrigation District General Manager Steve Knell, the BOR is out of compliance with their state permit, which creates some legal questions.
On June 28, BOR Public Affairs Specialist Louis Moore said that the BOR will lower the flows in the Stanislaus to 1,500 cfs on July 1 and it will remain at that level until July 5. Then the flows will increase at 8 a.m. on July 5 to 1,750 cfs and then up to 2,000 cfs by 10 a.m.
Knell said that the BOR also contacted Tri-Dam (a partnership of OID and South San Joaquin Irrigation District for the Beardsley, Donnells and Tulloch dams) on June 27 and asked management there to build up storage in Beardsley Dam, which is upstream of New Melones. Beardsley outflows will be reduced 1,000 cfs, which results in inflows to New Melones being lessened. However, Knell said this manipulation of the watershed can only be done for about five to six days then more water has to be released from Beardsley downstream.
Moore said that the concerns of the community about the river being high are valid but that the BOR tries to make sure those considerations are met and that they manage the water.
He acknowledged that the pending storm will create more runoff and a string of higher temperatures, which are predicted for the July 4th weekend, would also increase runoff.
“Precipitation in the Sierras does concern us,” Knell said. “Snow, then rapid warming, those are all events that concern us.”
Knell also noted that this is a 164 percent water year this year.
Moore said that conditions play a major role in runoff and what gets released but he would not state what the expected flows on the river would be for the rest of the summer because he said they have no way to know the conditions before they happen, except to refer to historical data.
Knell said that OID received a new operations plan earlier this week from BOR that states that the Stanislaus, downstream of Goodwin Dam, will be 2,000 cfs from July through September, with the exception of the aforementioned holiday weekend flows. Knell added that there is still a lot of water to come off the Sierras as there is a lot stored in the form of snow and OID feels that BOR should have been releasing water sooner in the year.
A big issue for OID in all of this is the fact that the spillway for New Melones has never been completed. Spillways are for emergencies when the primary outlet of the dam can’t keep up with the inflows from runoff and storage is too high. The primary outlet for New Melones allows water to go through at 8,300 cfs, Knell reported.
As of the June 28 morning report, New Melones’ available storage was approximately 144,000 acre feet. Inflows to New Melones have been over 9,600 cfs at the highest point in mid-June to 4,700 cfs as of the June 28 report. These numbers fluctuate daily, sometimes significantly. In an example, Knell said that 8,488 cfs inflow (on June 22) equals about 17,000 acre feet of inflow per day.
Though the dam was completed in 1979 and the reservoir filled in 1983, the New Melones spillway is only approximately one-mile complete while another one-mile stretch to the river is incomplete. Knell has called it the “spillway to nowhere.” He said the spillway was supposed to be done but they ran out of money and Congress never reauthorized completion of the project.
“A big snow event like this year…makes you think about the ‘what ifs,’” Knell said. “We’re the big losers if that spills.”
Tulloch reservoir is downstream of New Melones. Knell said that if water was spilled from New Melones, it would sweep a significant amount of trees and debris into the river and flush it into Tulloch. The Tulloch Dam has gates in its spillway and that debris would likely pile up and plug the gates, and raise the Tulloch water level.
“While it may not happen, why are we playing the risk game?” asked Knell. “Why aren’t we being more proactive and have a buffer?”
Knell said that it’s hard to get the Feds motivated to fix the spillway issue.
“Is it going to take a spill for them to fix this problem?” he asked.
He also said that as long as inflows stay high, the real risk comes if there’s a delayed, big runoff event and there’s not enough storage to play with.
“For the condition of the spillway, BOR should be more aggressive in managing the river so there’s not a problem,” Knell said, adding that OID plans to “beat the drum” more in Washington and work with local legislators to get the spillway finished.
Moore said that there is plenty of storage in New Melones; however, Knell said that OID would prefer that the BOR take a more conservative approach. Knell said that storage is still building behind New Melones and with the backoff on flow, that also converts to storage.
Pete Lucero, also of the BOR Public Affairs Office, stated online that they didn’t anticipate increasing releases above 2,000 cfs in the Stanislaus in July unless there are “extraordinary inflows due to snowmelt runoff in the upper watershed.”
The question that remains is what will be the snowmelt runoff? Knell reported that the highest accumulation of precipitation in the New Melones watershed was 45.33 inches in 1983. That year also had the highest inflow at 2.18 million acre feet. In the 2011 water year, we’ve accumulated 45.94 inches, making this the largest accumulation year by more than half an inch. He said that so far, only about 1.59 million acre feet has flowed into New Melones.
So how much is left in the watershed? The snow may not all melt this year, just how much and how quickly remains to be seen.
Knell said one thing is clear: “It’s going to be a long runoff season with the rivers high and cold for a good part of the summer. River rescue business should be good, unfortunately.”
He added that people should just stay out of the river in years like this.