ITEM: INFORMATIONAL ITEMS/STAFF REPORTS
25. CARMEL
RIVER FISHERY REPORT
Meeting
Date: December 15, 2003 Budgeted: N/A
Program/Line
Item No.: Aquatic
Staff Contact: Dave Dettman/ Resources Fisheries, 2.4
Beverly Chaney Cost Estimate: N/A
General Counsel Approval: N/A
Committee Recommendation: N/A
CEQA Compliance:
N/A
AQUATIC HABITAT AND FLOW CONDITIONS: During November 2003, Carmel River streamflow conditions were critical or lethal for rearing juvenile steelhead in the lower river and good for rearing fish upstream of Schulte Road Bridge. In October, mean daily streamflow recorded at the District’s Carmel River Sleepy Hollow Weir gaging station averaged 8.0 cubic feet per second (cfs) and ranged from 7.3 to 9.2 cfs.
In November
2003, 0.87 inches of rainfall was recorded by Cal-Am at San Clemente Dam
(SCD). The long-term November average
at this site is 2.21 inches. For Water
Year 2004 through the end of November, the total rainfall is 1.14 inches, or
39% of average.
The
Carmel River Lagoon has been closed since July 2, 2003. In November, water depth continued to
recover from the seasonal minimum in August, and now is ranging below five feet
(See chart below). Streamflow at the
District’s Highway One Bridge declined to zero on July 27 and the riverfront
receded upstream, ultimately stabilizing at point approximately 0.5 mile
downstream of Schulte Road Bridge in early September. During November, the riverfront advanced downstream to near
Cal-Am’s Cypress Well in response to lower Cal-Am production.
Carmel Lagoon Water Level November 2003
SLEEPY HOLLOW STEELHEAD REARING FACILITY: As of the first week in December, the Facility is in demobilization mode, with only the river pumps running. The cooling tower has been shut down and staff is dip netting and electrofishing the fish from the rearing channel. By September 5, 2003, staff had stocked 28,327 fish at the Facility, or approximately one-half of the total number rescued from the lower river. As of November 30, 2003, an estimated total of 21,235 fish had survived including 13,385 fish on hand, 7,850 fish that were released, and 576 fish that voluntarily escaped to the river. To date, overall survival is estimated at 75% (21,235/28,327).
Turbidity Levels:
Throughout this year’s rearing season, the turbidity of water at the
intake to the Facility has been elevated due to continuing operations at San
Clemente Dam, where Cal-Am has been required to lower the water surface
elevation for the Interim Drawdown Project (IDP). The purpose of the IDP is to reduce the safety risk to downstream
lives, following a seismic failure of San Clemente Dam. One environmental consequence of the IDP has
been elevated turbidity of water released through the dam. During the IDP,
turbidity levels in the reservoir have ranged from approximately 7 to 68
Nephelometric Units (NTUs), representing a 10- to 100-fold increase compared to
typical pre-project levels (See inset chart below).[1] Currently, at the Facility intake turbidity
is about 20 NTU’s, significantly above pre-project levels and in a range that
can affect fish health. While the
increased turbidity has not apparently caused direct mortality to fish in the
Facility, levels in the 15+ ranges appear to interfere with feeding, especially
in rearing tanks, where particles tend to remain in suspension. In the upper end of the rearing channel,
turbidity is equal to or slightly lower than river levels, but some of the
suspended material settles out in the channel.
Sediment Discharge from San Clemente Dam and
Early Release of Fish from Sleepy Hollow: As reported last month and
described above, staff has been making early releases of fish from the Facility
on account of the risk posed by the potential discharge of sediment from San
Clemente Reservoir. As of December 2,
2003, this appears to have been a prudent decision because the sediment plume
at the lower end of the inundation zone has piled sand and silt onto the upstream
face of the dam, and is within 50 horizontal feet of the newly bored ports in
the dam. Last month, staff reported
that sediment could begin moving past the dam within the next six months to two
years. It now appears (see photos below) that this could occur within
the next month, or so, depending on streamflow, and whether Cal-Am is allowed
to close the ports and let the reservoir spill at elevation 525 feet, or is
required to hold the current elevation of 514 feet, whenever feasible. While there is some small risk associated
with releasing the fish earlier, before the lower river has advanced to the
lagoon, staff believes the risk of holding fish for an extended period, while
increased sediment is mobilized during early storm events, is far greater.
December 2, 2003 Photos of Sediment Plume in Lower
San Clemente Reservoir
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