ITEM:

INFORMATIONAL ITEM/STAFF REPORT

 

21.

QUARTERLY CARMEL RIVER RIPARIAN CORRIDOR MANAGEMENT PROGRAM REPORT

 

Meeting Date:

January 27, 2025

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 was 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 October: Sleepy Hollow, Dampierre, 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                             0.23

            July – September                    1.53

            October – December               0.32 AF

           

            Year-to-date                            2.08 AF

 

MONITORING OF RIPARIAN VEGETATION:   Starting in July 2024, staff recorded bimonthly 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 21-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.

 

Monitoring results for the 2024 season show that riparian vegetation experienced little to no moisture stress associated with groundwater extraction because of the wet winter (2023-2024). The graph in Exhibit 21-A shows average canopy ratings for willows and cottonwoods in selected restoration sites in lower Carmel Valley.  The graph in Exhibit 21-B shows impacts to water table elevations. The types of monitoring measurements made during July through mid-October are as follows:

 

            Monitoring Measurement                                       

            Canopy ratings                                                (See Exhibit 21-A for trends.)          

            Groundwater levels (monitoring wells)          (See Exhibit 21-B for trends.)          

            Groundwater pumping (production wells)

 

OTHER TASKS PERFORMED SINCE THE OCTOBER 2024 QUARTERLY REPORT:

 

1.                  District staff carried out vegetation management along nine reaches of the Carmel River to prevent debris dams or diversion of high winter flows into vulnerable streambanks. The majority of the work includes cutting downed trees into smaller sections so they can safely move through the system during high flows.

 

EXHIBITS

21-A    Average Willow and Cottonwood Canopy Rating

21-B    Depth to Groundwater

                       

U:\staff\Boardpacket\2025\012725\Informational Items\21\Item-21.docx