ITEM:

INFORMATIONAL ITEMS/STAFF REPORTS

 

23.

QUARTERLY IRRIGATION PROGRAM AND RIPARIAN PROJECTS REPORT

 

Meeting Date:

October 17, 2005

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 2005 at nine Monterey Peninsula Water Management District (District) riparian habitat restoration sites.  The following irrigation systems were in use May through September:  DeDampierre, Trail and Saddle, Scarlett, Begonia, Schulte South, Schulte Bridge, Schulte, Valley Hills, and All Saints.

 

            Water Use in Acre-Feet (AF)

            January - March 2005              0.00 AF

            April - June 2005                     1.59

            July – September 2005             6.15

            Year-to-date                            7.74 AF

 

MONITORING OF RIPARIAN VEGETATION:  During the months of May through September 2005, 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 2005 monitoring season to date show that non-irrigated sample willows at Valley Hills became severely stressed in late September. Sample trees are not irrigated intentionally to see how they respond in a natural setting.  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 23-A and 23-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 2005 are as follows:

 

            Monitoring Measurement                                        

 

            Dawn leaf water potential                                  (See Exhibit 23-A for trends.) 

            Soil moisture (tensiometers)                                         

            Groundwater levels (monitoring wells)               (See Exhibit 23-B for trends.) 

            Groundwater pumping (production wells)                     

           

 

 

OTHER TASKS PERFORMED SINCE MARCH 2005 REPORT:

 

1.         Carmel River Riparian Irrigation System: District staff (Lyons, Bekker, Christensen, and Kenner) tuned up the Rancho Cañada and Cypress Irrigation Systems by repairing damaged irrigation lines and replacing clogged emitters. Both of these systems are designed to offset impacts to riparian vegetation associated with groundwater pumping in the vicinity of Cal-Am production wells and to help new riparian restoration plantings become established.

 

2.         Carmel River Vegetation Management Project Notification: On July 19, 2005, District staff notified the U.S. Army Corps of Engineers, NOAA Fisheries, U.S. Fish and Wildlife Service, Monterey County, and the Regional Water Quality Control Board of four sites that are scheduled for vegetation management activities this fall. A total of approximately 1,180 lineal feet of stream encompassing approximately 0.40 acre in the channel bottom will be affected by the project.  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 the streambanks during high flow periods.

 

3.         Supplemental Carmel River Action Plan: On September 26, 2005, District staff (Christensen and Hampson) provided information on District restoration activities on the Carmel River for the Planning and Conservation League Foundation (PCLF) tour of San Clemente Dam, Carmel River Lagoon, and Valley Hills Restoration Project. Several consultants and the PCLF are working on a supplemental Carmel River Action Plan that is exploring solutions for the San Clemente Dam seismic retrofit.          

 

EXHIBITS

23-A    Average Dawn Leaf Water Potential

23-B    Depth to Groundwater

 

 

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