EXHIBIT
14-B
MONTEREY
PENINSULA WATER MANAGEMENT DISTRICT
January 26, 2012
1. CALL TO ORDER/ROLL CALL
2.
PUBLIC
COMMENT - Anyone
wishing to address the Committee on a matter not listed on the agenda may do so
during Public Comment.
3.
CONSENT
CALENDAR
A. Minutes from the October 27, 2011 Regular
Meeting of the Carmel River Advisory Committee Regular Meeting are attached as Exhibit A.
ACTION REQUIRED:
The Consent
Calendar contains routine items that will be approved or accepted upon
ratification of the Consent Calendar. A
Committee member may request that a Consent Calendar item be considered
separately by the Committee.
4.
UPDATE
AND DISCUSSION ON CARMEL RIVER WATERSHED ACTIVITIES
BACKGROUND: This is a regular agenda item. Lorin Letendre, President of the Carmel River
Watershed Conservancy (CRWC), will update the Committee about CRWC activities.
RECOMMENDATION: No action is required. This is a discussion item.
5.
DISCUSSION
OF LOS PADRES DAM AND RESERVOIR
BACKGROUND: Los Padres Dam and Reservoir lie
approximately 25 miles upstream of the Pacific Ocean and the reservoir provides
the only significant surface storage in the Carmel River watershed. Recently, there has been renewed interest in
this dam and reservoir for the following reasons:
·
NOAA Fisheries, the
California Department of Fish and Game (CDFG), California American Water
(Cal-Am), and MPWMD are cooperating to design plans and construct passage improvements
at the dam for downstream steelhead migrants (smolts and adults);
·
The reservoir has lost more
than 40% of its storage capacity to siltation since 1948; Cal-Am has proposed completing a feasibility
study in 2012 for dredging sediment out of the reservoir;
·
Beginning in 2017, the
Monterey Peninsula is facing a significant cutback in the amount of water that
can be diverted from the Carmel River; MPWMD would like to evaluate the
potential for increasing the water supply by expanding storage at the
reservoir;
·
NOAA Fisheries is
encouraging Cal-Am to study the feasibility of removing Los Padres Dam to avoid
impacts to both upstream and downstream steelhead migration;
·
Significant channel degradation
has occurred between Los Padres Dam and San Clemente Dam and in the river
downstream of San Clemente Dam as a result of sediment starvation (entrapment
of sediment from the upper watershed by both Los Padres and San Clemente Reservoirs);
The
following is a brief listing of the status and current operation of the dam and
reservoir and some of the associated issues:
Site
Facilities:
·
Dam and reservoir constructed
in 1948 and 1949 by California Water and Telephone (Cal-Am predecessor) to
supply water needs of the Monterey Peninsula;
·
Located at River Mile
24.8, about 12 miles east of Carmel Valley Village;
·
Embankment dam
(earthfill) about 150 feet high; concrete spillway 18 feet high, 110 feet wide,
600 feet long (approximate dimensions);
·
Spillway capacity estimated
to be about 38,000 cubic feet per second (cfs) (flow to top of spillway);
·
Maximum release through the
dam is about 30 cfs;
·
Contributing watershed drains
a 44.8 square mile area that is partly National Forest and partly Ventana
Wilderness;
·
Original reservoir
capacity was 3,030 acre-feet; current capacity has been reduced to 1,775
acre-feet due to siltation; 100% siltation is estimated to occur by year 2100
or earlier (based on historical rate);
·
Reservoir surface area is
about 55 acres at spillway elevation; maximum extent of reservoir inundation
extends upstream to approximately the confluence with Danish Creek.
Operations:
·
The reservoir normally
fills and spills in fall/winter after several inches of rainfall (the only recorded
exceptions to this since 1949 were during the 1976-77 drought and one year
during the 1987-91 drought); after the reservoir fills, the watershed is
considered to be in an “uncontrolled condition” – i.e., the reservoir provides
no flood control for downstream properties;
·
There are three fish
ladders below the dam (one fully functional, one partially functional, one
abandoned); Cal-Am operates a trap and truck operation to move steelhead upstream
of the dam in winter; juvenile and adult steelhead migrate downstream over the
spillway;
·
Releases from storage are
made to the Carmel River main stem once the level drops below the spillway; rediversion
of flow occurs at Cal-Am owned municipal production wells downstream of San
Clemente Dam, primarily between River Mile 3 and 8; releases are governed under
a quarterly budget process set up by a Memorandum of Agreement between CDFG,
Cal-Am, and MPWMD. NOAA Fisheries also
participates in water budget decisions;
·
Releases from storage
during the dry season generally range from 5 to 15 cfs, depending on inflow
conditions and water year type; the effect of the reservoir on water
temperature in the river can be variable and result in raising or lowering the
water temperature in the river by several degrees; releases during periods of
very low storage can be both warmer than incoming river flow and anoxic (low or
no dissolved oxygen);
Water
Rights:
·
SWRCB issued permit 7130A
for Los Padres Dam in 1948; Cal-Am was licensed in 1985 (License 11866) to
divert up to 3,030 acre-feet per annum (AFA) between October 1 of each year
through May 31 of the following year; the right to divert was subsequently
reduced to 2,179 AFA by SWRCB Order 95-10;
·
SWRCB Permit 20808B –
New Los Padres Dam – MPWMD currently holds rights to 18,674 AFA (note: this is
junior to all other rights along the Carmel River);
Issues
to consider:
·
Los Padres Dam blocks
upstream steelhead migration to approximately 50% of the spawning habitat in
the Carmel River watershed; the long concrete dam spillway can injure, abraid, or stress fish that migrate downstream;
releases from storage during times of poor water quality can degrade downstream
aquatic life and in the worst case result in a fish kill (e.g., as occurred in
1981);
·
In dry periods, releases
from storage in the summer typically constitute more than 50% and up to 90% of
the flow in the river downstream of Los Padres Dam; without releases from
storage, it is estimated that the Carmel River could dry up or pool up in the lower
24 miles (to the confluence with Cachagua Creek) during very dry periods;
·
The Sleepy Hollow
Steelhead Rearing Facility, located a mile downstream of San Clemente Dam, is
dependent on a flow of at least three cubic feet per second in the river in
order to operate;
·
Cal-Am’s diversion right
of 2,179 AFA at Los Padres Dam is a substantial portion of its 3,376 AFA of authorized
rights to divert in the Carmel River; the
right to divert at the dam was reduced from 3,030 AFA, which was the
original storage capacity of the reservoir in 1948, to 2,179 AFA in 1995 (based
on the estimated storage capacity at that time); if reservoir storage is not
maintained, SWRCB could further reduce the right to divert to storage and to beneficial
use in the future; a reduction in authorized Carmel River diversion rights
would have a significant effect on the domestic water supply to the Monterey
Peninsula;
·
The upper watershed is
steep and prone to episodes of erosion; periodic large wildfires can be followed
by very wet periods with high rates of erosion; the dam and reservoir
disconnect habitat and natural river functions between the upper and lower
portions of the watershed; Los Padres Dam blocks movement of sediment and
significant quantities of large wood into the lower river from the upper
watershed and contributes to poor spawning habitat between San Clemente Dam and
Los Padres Dam; the reservoir contains approximately two million cubic yards of
sediment that would naturally have flowed into the lower river and to the
Carmel River State Beach; channel degradation in the lower 16 miles of the
river and lack of sand at the mouth of the river can be traced back in part to
sediment retention in the two main stem reservoirs in addition to former sand and
gravel mining operations in the lower river and at the Carmel River State Beach
between the 1920s and 1970s;
·
Recovering and
maintaining storage capacity is likely to be expensive; existing facilities
(dam, bridge, pipeline, roads) are more than 60 years old and may require
maintenance; maintaining storage capacity would require an ongoing maintenance
dredging program; there is limited area (~ 10 acres) near the site to store dredged
sediment;
·
Recovering or increasing
winter storage by dredging could allow for increased diversions to municipal
supply, increased summer releases in a portion of the river downstream, and more
flexibility in controlling water quality during dry period releases; stockpiled
gravel and cobble from a dredging program could be injected into the channel to
improve spawning habitat downstream of Los Padres Dam; spawning gravel would
eventually pass into the lower Carmel River and improve spawning habitat in
that reach;
·
Current Division of
Safety of Dams standards require a dam to safely resist maximum credible
seismic and flood forces; new procedures developed since 1948 for calculating a probable maximum flood (PMF)
show that the dam spillway will not pass a PMF at a level equal to or less than
the top of the spillway; modifications to the dam or reservoir may require improving
the spillway to meet the new standard;
·
Modifications to the dam
or reservoir could trigger additional mitigation activities for potential
impacts to steelhead, California red-legged frogs, wetlands, upland habitat,
historical and cultural resources.
Stakeholders
in the future of the dam and reservoir include: the current dam owner (Cal-Am);
several local, state, and federal agencies including the District, the Resource
Conservation District of Monterey County, CDFG, SWRCB, NOAA Fisheries, and the
U.S. Fish and Wildlife Service; non-profit groups such as the Carmel River
Steelhead Association, the Carmel River Watershed Conservancy, and the Planning
and Conservation League; recreational users (boating, fishing, hiking); and
research organizations such as the Watershed Institute at California State
University Monterey Bay. In addition,
the U.S. Forest Service (USFS) manages virtually all of the contributing watershed. USFS land management policies – particularly
for fire management – can have a direct effect on the volume of sediment and
large wood that enters the reservoir.
STAFF RECOMMENDATION: The Committee
should consider whether to sponsor a community workshop to take input on the
Los Padres Dam and Reservoir and its effect on water supply for the Monterey
Peninsula and on the environment of the Carmel River. If the Committee chooses to hold a workshop,
the following should be identified: stakeholders to be contacted; a time and
place for a meeting; a meeting facilitator; and agenda items for discussion.
ACTION REQUIRED:
This is a discussion item. The
Committee may take input from the public on this item and take action as
appropriate.
6.
STAFF
REPORTS - Staff
will report on the following:
a)
Integrated
Regional Water Management Planning (Hampson)
b)
Update
on Carmel River Watershed Rainfall and Flow Conditions (Christensen)
c)
Report
on Schulte Road Bridge Replacement Project (Hampson)
7.
ITEMS
TO BE PLACED ON FUTURE AGENDAS
Committee
members should bring up any new business at this time to determine whether it
should be included on a future meeting’s agenda.
8.
ADJOURNMENT
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