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ITEM: |
INFORMATIONAL ITEMS/STAFF REPORTS |
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26. |
QUARTERLY
IRRIGATION PROGRAM AND RIPARIAN PROJECTS REPORT |
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Meeting Date: |
January 27, 2005 |
Budgeted: |
N/A |
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From: |
David A. Berger, |
Program/ |
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General Manager |
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Item No.: |
N/A |
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Prepared By: |
Thomas Christensen |
Cost Estimate: |
N/A |
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General Counsel
Approval: N/A
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Committee Recommendation: N/A
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CEQA
Compliance: N/A |
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IRRIGATION
OF RIPARIAN VEGETATION: For calendar year 2004, the supplemental
watering of riparian restoration plantings resumed in April of 2004 at nine
Monterey Peninsula Water Management District (District) riparian habitat
restoration sites. The following
irrigation systems were irrigated April through October: DeDampierre, Trail and Saddle, Scarlett,
Begonia, Schulte South, Schulte Bridge, Schulte, All Saints, Valley Hills, and
San Carlos.
Water Use in Acre-Feet (AF)
April - June 2004 2.50
MONITORING
OF RIPARIAN VEGETATION: During the months of May through October
2004, staff took weekly measurements of leaf water potential 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 twice a month for pre-dawn leaf water potential. A total of 14 willows and 13 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. Soil moisture measurements are conducted at
three of these sites (San Carlos, Valley Hills, and Schulte) using
tensiometers. Soil moisture values are
measured at seven stations with 18-inch and 36-inch tensiometers in the soil
column. Combined with monthly readings
from the District’s array of monitoring wells and pumping records for
large-capacity Carmel Valley wells in the Cal-Am system, the District’s monitoring
provides insight into the status of soil moisture through the riparian
corridor.
Current
monitoring results for the 2004 monitoring season to date show that
non-irrigated sample cottonwoods and willows at Valley Hills became severely
stressed from mid July to early October. Sample trees are not irrigated
intentionally to see how they respond in a natural setting with groundwater
extraction. However, the projects as a whole are irrigated and riparian
vegetation is under threshold values. Willows are considered severely stressed
when values are 7.5 bars and above, while cottonwoods are considered severely
stressed when values are 10.0 bars and above.
The
graphs in Exhibit 26-A show impacts to water table elevations and
riparian moisture stress in selected restoration sites in the lower Carmel
Valley. On June 9, 2004, stream flow ceased in the Rancho Cañada area.
Currently stream flow has returned and the Carmel River is flowing to the
ocean.
The
types of monitoring measurements made during May through October 2004 are as
follows:
Monitoring Measurement
Dawn
leaf water potential (See Exhibit
26-A for trends.)
Soil
moisture (tensiometers)
Groundwater
levels (monitoring wells) (See Exhibit
26-B for trends.)
Groundwater
pumping (production wells)
OTHER
TASKS PERFORMED SINCE OCTOBER 2004 REPORT:
1.
In-Channel Vegetation Management:
On October 5, 2004, District staff (Christensen, Bekker, Lyons, and Watters)
modified a group of trees that fell across the Carmel River approximately 150
yards upstream of Rancho San Carlos Bridge. These trees were cut in large
sections to reduce their potential for creating a debris dam that could divert
winter flows into streambanks and lead to erosion and damage to
infrastructure. The cut tree was left in the channel to provide "large wood
habitat" consistent with state and federal resource agency requirements.
2.
San Carlos Irrigation System:
On October 20, 2004, District staff (Christensen, Wheeler, Bekker, and Lyons)
removed the temporary irrigation system from San Carlos Road Bridge downstream
past Cal-Am's San Carlos Well (1,770 feet). This system is designed to water
riparian plants on the bank of the river to help alleviate moisture stress
associated with groundwater pumping. This system was removed because we have
had significant rains and the river is working its way downstream.
3. Carmel River In-Channel Vegetation
Management: District staff, (Mark Bekker, Matt Lyons, Thomas
Christensen, and Larry Hampson) finished clearing vegetation in
constricted areas in preparation for winter flows in the Carmel River. Work was
completed at three sites along the Carmel River and extended for a total
of 500 linear feet. The District operated under its Regional General
Permit from the U.S. Army Corps of Engineers and an individual Streambed
Alteration Agreement with the Department of Fish and Game.
4.
Stream Bank Revegetation: District
staff, (Thomas Christensen, Mark Bekker, and Paul Watters) helped a
Carmel Valley resident, John Kenny, revegetate his exposed and eroding bank
along the Carmel River. A total of 30 willows were planted. The District also
provided information to Mr. Kenny on irrigation practices to help
establish the vegetation. As the willows mature they should help prevent
erosion and provide stability during higher flows.
5.
Carmel River Watershed Council (CRWC) Meeting: On December 2, 2004, District staff
(Christensen, Hampson, Watters, and Dettman) participated in a Technical
Advisory Committee (TAC) meeting to help develop the CRWC's
action plan. Topics of interest included sediment management, river flow
increases, and habitat improvements.
6. Carmel River
Advisory Committee Meeting: On
December 16, 2004, District staff (Hampson, Christensen, and Bell) met with the
Carmel River Advisory Committee. Tom Moss of Monterey County Water Resources
Agency reported on the Carmel River Flood Elevation Study that is currently
underway. Other topics of interest included an update on the San Clemente Dam
seismic retrofit project and staff activities on the Carmel River.
26-A Average
Dawn Leaf Water Potential
26-B Depth to
Groundwater
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