Meeting Date:

October 15, 2007





David A. Berger,




General Manager

Line Item No.:


Prepared By:

Thomas Christensen

Cost Estimate:



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 April of 2007 at eleven Monterey Peninsula Water Management District (District) riparian habitat restoration sites.  The following irrigation systems were in use April through September: DeDampierre, Trail and Saddle Club, Scarlett, Begonia, Schulte South, Schulte Bridge, Schulte, All Saints, Valley Hills, San Carlos, and Dow.


            Water Use in Acre-Feet (AF)

            (preliminary values subject to revision)


            January - March 2007   0.09 AF

            April - June 2006           1.25

            July – September            6.95

            Year-to-date                  8.20 AF


MONITORING OF RIPARIAN VEGETATION:  During the months of May through September 2007, staff recorded weekly 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 every week for canopy ratings based on a scale from one to eleven. This scale evaluates characteristics such as yellowing leaves and percentages of defoliation (see scale on Exhibit 29-A).  A total of 10 willows and 9 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 2007 monitoring season to date show that riparian vegetation has experienced moisture stress in some areas.  Some signs of yellowing and defoliation are occurring but the overall riparian corridor still shows resilience given the critically dry year. The graphs in Exhibit 29-A and 29-B show average canopy ratings for willows and cottonwoods in selected restoration sites in the lower Carmel Valley and impacts to water table elevations.


The types of monitoring measurements made during May through September 2007 are as follows:


            Monitoring Measurement                                        


            Canopy Ratings                                                (See Exhibit 29-A for trends.) 

            Soil moisture (tensiometers)                                         

            Groundwater levels (monitoring wells)   (See Exhibit 29-B for trends.) 

            Groundwater pumping (production wells)                     






1.         San Carlos Irrigation System: On July 9, 2007, District staff completed installation of the temporary irrigation system from Rancho San Carlos Road Bridge downstream past CAW’s San Carlos Well. This system irrigates a total of 3,600 lineal feet of riverbank vegetation and is designed to water riparian plants on the bank of the river to help alleviate moisture stress associated with groundwater pumping. This system will be removed after the first significant rains this fall.


2.         Schulte Road Bridge Irrigation System Expansion: District staff (Christensen, Bekker, and Lyons) recently expanded the Schulte Road Bridge Irrigation System by 600 lineal feet in the downstream direction. Staff noticed riparian vegetation stress in this area and decided to tie into an existing system to offset impacts from the critically-dry water year conditions, combined with CAW pumping from the alluvial aquifer.


3.         Annual River Clean Up: On August 30, 2007, District staff (Christensen, Bekker, Lyons, and Kenner) performed a portion of the annual Carmel River clean up from Rancho San Carlos Road Bridge to Rancho Cañada Golf Course.  Car parts, tires, and plastic were removed from the river bed.



29-A    Average Willow and Cottonwood Canopy Rating

29-B    Depth to Groundwater