26. QUARTERLY
IRRIGATION PROGRAM AND RIPARIAN PROJECTS REPORT
Program/Line
Item No.: N/A
Staff
Contact: Thomas Christensen Cost Estimate: N/A
General
Counsel Approval: N/A
Committee
Recommendation: N/A
CEQA Compliance:
N/A
IRRIGATION
OF RIPARIAN VEGETATION: The
supplemental watering of riparian restoration plantings in calendar year 2003
began in May at nine Monterey Peninsula Water Management District (District)
riparian habitat restoration sites and ended in October. The following irrigation systems were
operated May through October:
DeDampierre, Trail and Saddle, Scarlett, Begonia, Schulte South, Schulte
Bridge, Schulte, All Saints, and Valley Hills.
Quarterly use for the year to date is as follows:
Water Use in Acre-Feet (AF)
April - June 2003
1.38
MONITORING
OF RIPARIAN VEGETATION: During the months of May through October
2003, staff took weekly measurements of dawn 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 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 installed 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.
Monitoring
results for the 2003 monitoring season show that non-irrigated sample willows
and cottonwoods at Valley Hills and Schulte are severely stressed. Willows and
cottonwoods at Rancho Cañada and San Carlos were below threshold values. 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 Lower
Carmel Valley. As of August 4, 2003 stream flow ceased in the Rancho Cañada
area. Stream flow returned to the Rancho Cañada area on December 29, 2003.
Starting November 1, 2003, monitoring of riparian vegetation is suspended until
May of 2004 because there is sufficient soil moisture for maintenance and
growth of the vegetation.
The
types of monitoring measurements made during May through October 2003 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’S 2003 REPORT:
1.
Training
Assistance to Carmel River Watershed Conservancy (CRWC): On Saturday October 11, 2003, District
Staff (Larry Hampson and Thomas Christensen) participated in a CRWC workshop to
train volunteers in procedures for conducting a watershed assessment. The
CRWC has agreed to compensate the District for staff's time in the
workshop. At the October 30, 2003 meeting, the Board approved a contract
between the District and CRWC to provide additional services to assist in the
watershed assessment. For all work performed under this contract, the
District would be compensated for staff time.
2. In-Channel Vegetation Management: On October 28, 2003, District staff (Christensen, Hampson, Lyons, and Bekker) made modifications to two black cottonwoods that had fallen across the Carmel River channel downstream of Highway One near the Carmel Area Wastewater District treatment plant. The crowns of these trees were removed to prevent erosion associated with diversion of high flows and collection of debris.
3. Carmel
River Watershed Assessment: On Saturday, November 22, 2003, Thomas
Christensen and Larry Hampson conducted a workshop on the "Proper
Functioning Condition" method for assessing the health of riparian
corridors. The all-day workshop was being held at the Carmel Middle
School in cooperation with the Carmel River Watershed Council (CRWC) and
followed the same format as the previous workshop given in October. The
methodology will be used in the watershed assessment to
be carried out in 2004 under the sponsorship of the CRWC.
4. Large
Wood Habitat Structures Monitoring: District staff (Christensen and
Hampson) surveyed river cross-sections in the area of the large wood
habitat structures at the DeDampierre Ball Fields near Carmel Valley
Village. Cross-sections help track pool formation and river bed change
associated with the large wood installation, and is surveyed on
an annual basis.
U:\staff\word\boardpacket\2004\2004boardpacket\20040129\InfoItems_Reports\26\item26.doc