ITEM:

INFORMATIONAL ITEM/STAFF REPORT

 

20.

QUARTERLY CARMEL RIVER RIPARIAN CORRIDOR MANAGEMENT PROGRAM REPORT

 

Meeting Date:

October 21, 2024

Budgeted:

N/A

 

From:

Dave Stoldt,

Program/

N/A

 

General Manager

Line Item No.:

 

Prepared By:

Thomas Christensen

Cost Estimate:

N/A

 

 

 

 

                            

General Counsel Review:  N/A

Committee Recommendation:  N/A

CEQA Compliance:  This action does not constitute a project as defined by the California Environmental Quality Act Guidelines Section 15378.

 

IRRIGATION OF RIPARIAN VEGETATION: The supplemental watering of riparian restoration plantings is currently being carried out for the summer and fall season at seven Monterey Peninsula Water Management District (District) riparian habitat restoration sites. The following irrigation systems were in use April through September: Sleepy Hollow, deDampierre, Trail and Saddle Club, Begonia, Schulte, Valley Hills, and San Carlos.

 

            Water Use in Acre-Feet 2024 (AF)

            (preliminary values subject to revision)

            January - March          0.00 AF

            April - June                 0.41

            July – September        1.53

            Year-to-date                1.94 AF

 

MONITORING OF RIPARIAN VEGETATION:   Starting in July 2024, staff recorded 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 for canopy ratings based on a scale from one to ten. This scale evaluates characteristics such as yellowing leaves and percentages of defoliation (see scale on Exhibit 20-A). A total of 12 willows and 12 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. Combined with monthly readings from the District’s array of monitoring wells and pumping records for large-capacity Carmel Valley wells in the California American Water service area, the District’s monitoring provides insight into the status of soil moisture through the riparian corridor.

 

Current monitoring results for the 2024 monitoring season to date show that riparian vegetation is experiencing little to no moisture stress associated groundwater extraction because of the wet winter. It is important to note that irrigation around municipal wells is carried out to help alleviate impacts from water extraction. The graph in Exhibit 20-A shows average canopy ratings for willows and cottonwoods in selected restoration sites in lower Carmel Valley.  The graph in Exhibit 20-B shows impacts to water table elevations. The types of monitoring measurements made during July through September are as follows:

 

            Monitoring Measurement                                       

            Canopy ratings                                                (See Exhibit 20-A for trends.)          

            Groundwater levels (monitoring wells)          (See Exhibit 20-B for trends.)          

            Groundwater pumping (production wells)

 

OTHER TASKS PERFORMED SINCE THE JULY 2024 QUARTERLY REPORT:

 

1.                  Regional General Permit: District staff have been working to renew the Regional General Permit (RGP) with the U.S. Army Corps of Engineers. This permit allows the District to carry out vegetation management along the Carmel River. The work helps reduce blockages in the Carmel River and reduces the risk associated with downed trees and encroaching vegetation in the active channel. Vegetation management work is expected to be completed by the end of October.

 

EXHIBITS

20-A    Average Willow and Cottonwood Canopy Rating

20-B    Depth to Groundwater

                       

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