ITEM: |
CONSENT
CALENDAR |
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2. |
CONSIDER EXPENDITURE OF
FUNDS FOR EMERGENCY WINTERIZATION OF THE SLEEPY HOLLOW STEELHEAD REARING
FACILITY TO WITHSTAND WINTER STORM SEDIMENT LOAD FROM THE BASIN COMPLEX FIRE |
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Meeting
Date: |
November 17, 2008 |
Budgeted: |
No |
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From: |
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Program/ |
Aquatic Resources/ |
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General
Manager |
Line Item
Nos.: |
Fisheries |
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Prepared
By: |
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Cost
Estimate: |
$36,000 |
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General Counsel Approval: N/A |
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Committee Recommendation: The Administrative Committee considered this item on November 10, 2008 and recommended approval. |
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CEQA Compliance: A Notice of Exemption will be filed. |
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SUMMARY: The
recent Basin Complex Fire burned much of the Carmel River Watershed above Los
Padres Reservoir, and some of Finch Creek area in the upper Cachagua Creek
Watershed. Reports by experts from the
U.S. Forest Service predict that winter storm flows above Los Padres Reservoir
(LPR) may be up to 86% higher than normal for a given amount of rainfall, which
could translate into approximately 38% higher flows at San Clemente Dam. These higher flows may also carry up to nine
times as much sediment downstream into LPR as would normally occur. It is not known at this time how much of this
sediment will be trapped by LPR versus how much of the sediment will continue
downstream and affect the Sleepy Hollow Steelhead Rearing Facility
(SHSRF). However, based on 1994
estimates for sediment detention at LPR, more than 28% of this sediment may
move downstream. Therefore, without
immediate modifications to the Sleepy Hollow Steelhead Rearing Facility (SHSRF),
the District will be unable to reliably hold fish through the first significant
storm in December and will need to release them into the river early. The suspended sediment levels anticipated in
the Carmel River this winter are likely to cause the intake pumps to the SHSRF
to fail. This failure would likely
result in the loss of the majority of fish being reared in the facility within
about eight hours. Even if the pumps do
not fail, the severe sediment load itself would be harmful to the fish being
reared at the SHSRF, and could cause a significant increase in mortality if
turbid water conditions persisted for more than one week.
RECOMMENDATION: Staff recommends that the District Board authorize expenditure of funds up to $36,000 for an emergency project to winterize and protect the SHSRF from potential harmful sediment loads during storm flows. These funds are available in the District’s flood/drought emergency reserves. At this time, the recommended project is to retrofit the SHSRF’s two large circular tanks to be a temporarily recirculating system for up to eight weeks after the first major winter storms.
BACKGROUND: While
the District has existing plans to upgrade the water intakes to the SHSRF, those
plans are designed to solve coarse sediment or suspended bed load problems that
threaten the intake pumps in the coming years.
This probable increase in coarse sediment is due to the anticipated loss
of sediment trapping capacity at San Clemente Reservoir. Those plans do not address the suspended
sediments that are expected to be generated in the near term, beginning this
winter runoff season, until the watershed revegetates and the fire damaged
soils stabilize. Fisheries staff believe
that a potential order of magnitude increase in the amount of suspended
sediment normally observed in SHSRF intake waters in recent winters, will make
operation of the SHSRF untenable during any large storm, and for weeks after
most of this year’s winter storms. The
water will likely be so murky, with zero visibility, that the fish will not be
able to feed, and staff will not be able to see them while attempting to net
them out of the rearing channel. This
level of suspended sediment also reduces the fishes’ ability to breath and irritates
their gills to the extent that some will try to jump out of the rearing channel. The suspended sediment load may also be so
great as to interfere with the District’s backpack electrofisher, which is the
method used on the last pass to capture remaining fish. It takes two to three weeks for a five-person
crew to remove fish from the 800-feet long rearing channel, and the pumps could
fail at any time under an extreme sediment load, which could result in a near
complete loss of any fish remaining in the rearing channel. As a result, Fisheries staff have been consulting
with representatives of the Natural Resource Conservation Service, Resource
Conservation District of Monterey County, State Office of Emergency Services,
National Marine Fisheries Service (NMFS), and the California State Department
of Fish and Game (CDFG) as to what options should and could feasibly be
pursued. These discussions have led to three
options:
1) Isolate the SHSRF from its river intake, and
turn it into a recirculating system, whereby fish would continue to be reared
in the rearing channel using its static water volume, filtered and
re-circulated back to the headworks using equipment leased from Rain-for-Rent. This lease would be for eight weeks and would
cost approximately $23,000. In addition to this lease, electrical work would
also be required to accommodate the recirculating system. A draft conceptual diagram of the plumbing
and pumps for the recirculating rearing channel is included as Exhibit 2-A.
2) Remove the fish from the rearing channel in early
December, release the smallest ones into the river and hold the larger ones in
the two 22-foot and 30-foot circular Tanks #1 and #3, that were part of the
original Facility, but have not been in use in recent years. These tanks would need to be plumbed with
modular aquaculture filtration units, that include U.V. sterilization of the
filtered effluent, before it is returned to the tanks. Based on preliminary estimates, modular units
for this option would cost approximately $31,200, not including additional
electrical upgrades An example of this
type modular filtration system for the rearing tanks is included as Exhibit 2-B.
3) Begin releasing all of the 30,000 plus
steelhead being held in the SHSRF, a) as soon as we have any significant
forecast for large winter storms, or b) as soon as Los Padres Reservoir
approaches the level at which it will spill freely and no longer impede
sediment coming downstream, or c) December 1, whichever occurs first.
Option #1: Staff
are still refining this option based on the Rain-for-Rent
bid, and hope to finalize the design by the week of November 10, 2008. If this approach is successful, it could
provide a long term back-up for some of the SHSRF intake upgrades, and the
District could eventually purchase the pipe, pumps, and filter systems
necessary to make the installation permanent.
If the movement of coarse bedload were to threaten or break the normal
intake pumps under a new intake design, then the SHSRF could be taken off line
and run in a recirculating mode, while the intake pumps were pulled for repair
or replaced with stand-by pumps. This
approach allows the rescued fish to continue living in the rearing channel,
while conditions for survival in the river may be very poor. The drawback of this approach is that it
requires balancing the flow of two sets of pumps, wiring them into the existing
facility alarm system, and filtering the large volume of recirculating rearing channel
wastewater, which may slowly accumulate organic toxins and wastes from the
steelhead being reared in it.
Option #2: The
second option of rearing fish in the two large diameter tanks is potentially
more expensive, but is technologically simpler.
Staff does not yet know if the modular filtration units can be shipped
and installed in time before the winter storms.
The District would also own the equipment being purchased versus leasing
it annually. However, there are two
significant drawbacks. The fish face an
extra stage of handling from the rearing channel into the tanks, then back into
the river, versus going directly from the rearing channel to release, and this
will increase SHSRF holding mortality. This
approach will also increase unaccounted for fish losses due to intra-specific
predation in the open water of a circular tank that does not have any escape
cover. So we could only keep two of the
largest size classes of fish, and the rest would still have to be released to
the river, so they would not be preyed upon in the tanks.
Option #3: The
last option is the least costly, but is not congruent with the SHSRF’s mitigation
objectives of holding fish until the lower river habitat they were rescued from
has been re-wetted and allowed to recover for up to 30 days. Fish released early from the SHSRF will
compete for food and space with, and prey on, the smaller fish living in the
river. Despite the recent rain, flow in the
river is still very low at this time, flowing approximately six cubic feet per
second at the USGS Robles Del Rio gaging station. The river front has also not yet advanced
very far downstream from the point it dried back to in the summer. Thus, there are not likely to be enough
holding areas to readily accommodate an additional 30,000 plus steelhead from
the SHSRF, in approximately eight to nine miles of river. This approach might be mitigated by
increasing flows from Los Padres Reservoir to increase habitat volume. Any flow increases will need the concurrence
of California American Water, CDFG, and NMFS and require a thorough evaluation
of their potential impacts to water supply.
The impending winter storm flows are also likely to bring so much
sediment downstream that it could harm significant numbers of the fish holding
in the river, which may be unable to find shelter from the storm flows in
zero-visibility water, and may be harmfully affected if not killed by the
suspended sediment load. Releasing the
SHSRF fish into this environment before they are able to access the ocean could
cause significant mortality to the rescued fish that have been carefully reared
this year, and reduce their contribution to the returning adult run over the
next three to four years.
Risk Analysis: It
is important to consider the qualitative risks of the potential loss of steelhead
productivity in evaluating these three options.
The first option of recirculating and filtering the rearing
channel’s flows is the most experimental, and staff are still in the process of
designing it
with enough redundant systems and fail safes to make it as reliable as
possible. It depends on maintaining all
of the recirculating volume of the rearing channel, as we will not be able to
replace any losses with river water, as it will be too sediment-laden to
utilize. We will fill Tank # 3 with approximately
8,950 gallons of water as a reserve supply.
If this system fails, we would have only about eight hours to get as
many fish as possible out of the rearing channel and into the river, before the
dewatering of the channel would begin stranding fish. The benefit of this option, is that if it
does not fail, the fish are not handled an extra time versus the second option,
and continue to be reared in the environment they have become used to.
The second option of moving most fish into the 22-foot and 30-foot
circular rearing tanks requires more fish handling than normal, and the fish
being held in the open rearing tanks might be subject to a great deal of
cannibalism. If we can get them to feed
heavily enough, cannibalism may be minimal, but it may take the fish a few days
to as much as few weeks to adjust to a new environment and return to regular
feeding patterns. This option relies on
pre-fabricated filter systems designed for aquaculture and aquarium systems
that are very reliable. If they fail, the
tanks would hold their volume, and staff could release all the fish to the
river in only a couple of days, if needed.
The third option follows normal SHSRF procedures, but occurs weeks
prior to the time we would prefer to release fish. The risk to the steelhead we have reared is
that they may find themselves in crowded, low-flow conditions, prior to the
return of winter storm flows, competing with the natal fish in the river. Then, once the first large storms hit, the
fish may be unable to find refuge from storm flows in the crowded habitat, and
be tumbled down-river in very turbid water.
The severe turbidity and sediment load of this winter’s storms may cause
very high mortalities of any fish in the river, and we would be losing the
mitigation benefit of having reared many of these fish, if they die before
reaching the ocean.
IMPACT TO STAFF/RESOURCES: If the Board wishes to pursue either of these options as a potentially effective approach to keeping the SHSRF running during future winter storms, then funds would need to be authorized for this effort this Fiscal Year. Pursuing these alternatives will take a significant amount of the Associate and Senior Fisheries Biologists’ time as project managers, and will delay the production of the 2007-2008 Annual Mitigation and Monitoring Report by two to three months. If the approach is proven tenable this winter, then funds would be needed in the following Fiscal Years, if the Rain-for-Rent contract is renewed or another equivalent bidder is found. Informal contacts with State and Federal resource agencies responsible for steelhead management indicate that they cannot provide any grant funding to underwrite this effort, but applications have been made to the Federal Emergency Management Agency and the State Office of Emergency Services for funding to offset part or all of these expenses. District staff will continue to pursue such applications for funding as directed by the Board, as a means to offset potential costs to the District for this purpose.
EXHIBITS
2-A Draft Conceptual Diagram of the Plumbing
and Pumps for a Design of a Recirculating Rearing Channel
2-B Example of a Modular Filtration System for
the Rearing Tanks at the Sleepy Hollow Rearing Facility
U:\staff\word\boardpacket\2008\2008boardpackets\20081117\ConsentCal\02\item2.doc