ITEM:

INFORMATIONAL ITEMS/STAFF REPORTS

 

26.

QUARTERLY IRRIGATION PROGRAM AND RIPARIAN PROJECTS REPORT

 

Meeting Date:

October 16, 2006

Budgeted

N/A

 

From:

David A. Berger,

Program/

N/A

 

General Manager

Line Item No.:

 

Prepared By:

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 resumed in May of 2006 at eight Monterey Peninsula Water Management District (District) riparian habitat restoration sites.  The following irrigation systems were in use May through September: Trail and Saddle Club, Scarlett, Begonia, Schulte South, Schulte Bridge, Schulte, All Saints, and Valley Hills. One additional site came online in September with the completion of an irrigation system at the emergency bank stabilization project at the Dow and Kenny properties.

 

         Water Use in Acre-Feet (AF)

         January - March 2006   0.00 AF

         April - June 2006        0.89

         July – September 2006 3.28

         Year-to-date             4.17 AF

 

MONITORING OF RIPARIAN VEGETATION:  During the months of May through September 2006, 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 2006 monitoring season to date show that riparian vegetation is below threshold stress levels.  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 and 26-B show impacts to water table elevations and riparian moisture stress in selected restoration sites in the lower Carmel Valley.

 

The types of monitoring measurements made during May through September 2006 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 JULY 2006 REPORT:

 

1.       Public Outreach to Carmel Valley and Carmel Kiwanis: The District’s Riparian Projects Coordinator, Thomas Christensen, updated the Carmel Valley and Carmel Chapter of the Kiwanis on the District’s Environmental Protection Program, our ASR project, and the San Clemente Dam Seismic Safety Project EIR/EIS. Highlights included a discussion of the alternatives for the San Clemente Dam and the basic principles behind the ASR Phase 1 Project.

 

2.       Carmel River Vegetation Management:   During the week of September 25, 2006, District staff (Christensen, Bekker, Lyons, Watters, and Kenner), along with a California Conservation Corps (CCC) crew, performed vegetation management activities at four sites where vegetation has blocked the main channel of the Carmel River. Vegetation was removed at these constrictions to prevent potential bank de-stabilization that could occur during winter high flows. Three additional sites will be addressed in the month of October.        

 

EXHIBITS

26-A   Average Dawn Leaf Water Potential

26-B   Depth to Groundwater

 

 

 

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