ITEM: |
INFORMATIONAL
ITEMS/STAFF REPORTS |
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15. |
QUARTERLY CARMEL RIVER RIPARIAN CORRIDOR
MANAGEMENT PROGRAM REPORT |
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Meeting Date: |
October 16, 2017 |
Budgeted: |
N/A |
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From: |
Dave Stoldt, |
Program/ |
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General Manager |
Line Item No.: |
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Prepared By: |
Thomas Christensen and |
Cost Estimate: |
N/A |
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Larry Hampson |
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General Counsel Review: N/A |
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Committee Recommendation: N/A |
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CEQA
Compliance: This
action does not constitute a project as defined by the California
Environmental Quality Act Guidelines Section 15378. |
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IRRIGATION
OF RIPARIAN VEGETATION: The
supplemental watering of riparian restoration plantings resumed for the summer
season in 2017 at six Monterey Peninsula Water Management District (District)
riparian habitat restoration sites. The
following irrigation systems were in use May through September: deDampierre, Trail
and Saddle Club, Begonia, Schulte, Dow, and Schulte Bridge.
Water Use in Acre-Feet (AF)
(preliminary values subject
to revision)
April - June 2017 1.39
MONITORING
OF RIPARIAN VEGETATION: Starting in June 2017, staff recorded monthly
observations of canopy vigor on target willow and cottonwood trees to provide
an indication of plant water stress and corresponding soil moisture
levels. Four locations (Rancho Cañada,
San Carlos, Valley Hills, and Schulte) are monitored monthly for canopy ratings
based on a scale from one to ten. This scale evaluates characteristics such as
yellowing leaves and percentages of defoliation (see scale on Exhibit 15-A). A total of 12 willows and 12 cottonwoods at
these locations provide a data set of established and planted sample trees that
are representative of trees in the Carmel River riparian corridor. Combined
with monthly readings from the District’s array of monitoring wells and pumping
records for large-capacity Carmel Valley wells in the California American Water
service area, the District’s monitoring provides insight into the status of
soil moisture through the riparian corridor.
Current
monitoring results for the 2017 monitoring season to date show that riparian
vegetation is below threshold moisture stress levels. At present, the Carmel River is still flowing
to the Lagoon and providing plenty of water for established plants along the
riparian corridor. The graph in Exhibit 15-A shows average canopy ratings for
willows and cottonwoods in selected restoration sites in lower Carmel
Valley. The graph in Exhibit 15-B shows impacts to water table elevations.
The
types of monitoring measurements made during June - September 2017 are as
follows:
Monitoring Measurement
Canopy
ratings (See
Exhibit 15-A for trends.)
Groundwater
levels (monitoring wells) (See Exhibit
15-B for
trends.)
Groundwater pumping (production
wells)
OTHER
TASKS PERFORMED SINCE THE JULY 2017 QUARTERLY REPORT:
1.
Carmel
River Vegetation Management: During
the month of September, District staff have been carrying out Vegetation
Management along the Carmel River at 15 sites where downed trees or standing
vegetation has created a blockage in the active channel. This work is carried
out with permits from the U.S. Army Corps of Engineers, NOAA Fisheries, U.S.
Fish and Wildlife Service, California Department of Fish and Wildlife (CDFW),
and the Regional Water Quality Control Board. The goal of the vegetation
management activities is to reduce the risk of streambank erosion along
riverfront properties where vegetation encroachment could potentially
divert river flows into streambanks during high flow periods.
2.
Instream Flow Incremental Method Study: MPWMD fisheries staff collected additional data from
the river channel about fish presence and effects of winter storms, which filled
many of the deep pools with sand. The
District’s Consultant (Normandeau Inc.) will test whether these changes significantly
affect steelhead habitat. A final IFIM
report and memo on changes in channel conditions should be available in the 4th
quarter of 2017.
3.
Los Padres Dam Long-Term Plan: The first
Technical Review Committee (TRC) meeting was held on August 3, 2017. For a dredging operation, the Consultant team
recommended against using steep canyon areas upstream of the reservoir for placing
dredged material and instead determined that all material presently within the
reservoir could be placed on Cal-Am property downstream of the existing
dam. It was estimated that an average of
16,000 to 34,000 cubic yards of material per year accumulates in the reservoir
(about 32,000 to 68,000 tons).
For a reservoir expansion alternative, options include
installing a temporary rubber dam or permanent dam raise, a new dam downstream
or a combination. For a dam removal alternative, phased
(multi-year) removal by elevation was deemed not feasible because an operating
spillway would be required after each removal.
Partial or full removal of the embankment is feasible if the reservoir
is to be abandoned.
The Consultant will refine
alternatives before convening the second TRC meeting in January, which will
focus on evaluating alternatives.
4.
Los Padres Dam Fish Passage Study: The
Consultant team presented a preliminary ranking of passage alternatives showing
a retrofit or replacement of the existing trap and truck operation as the
highest ranked alternative for upstream passage. The highest ranked alternatives for
downstream passage were a floating surface collector placed at the head or reservoir or at about
mid-reservoir to capture downstream migrating fish and transport them to the
dam. The Technical Review Committee was asked to comment on evaluation criteria
and rankings.
5.
Stormwater Resource Plan
(SRP):
Staff participated in the first Technical Advisory Committee meeting to develop
the Stormwater Resource Plan and provided requested information to the
consultant team developing the plan. The
focus of the SRP is to identify sources of stormwater throughout the Monterey
Peninsula that can be recycled as new water supply.
EXHIBITS
15-A Average Willow
and Cottonwood Canopy Rating
15-B Depth to
Groundwater
U:\staff\Boardpacket\2017\20171016\InfoItems\15\Item-15.docx