ITEM:

INFORMATIONAL ITEM/STAFF REPORT

 

20.

QUARTERLY CARMEL RIVER RIPARIAN CORRIDOR MANAGEMENT PROGRAM REPORT

 

Meeting Date:

October 16, 2023

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 six 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, and San Carlos.

 

            Water Use in Acre-Feet 2023 (AF)

            (preliminary values subject to revision)

            January - March          0.00 AF

            April - June                 0.04

            July – September        0.83

            Year-to-date                0.87 AF

 

MONITORING OF RIPARIAN VEGETATION:   Starting in July 2023, 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 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 2023 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 2022 QUARTERLY REPORT:

 

1.                  Carmel River Vegetation Management: In September, District staff carried out vegetation management at ten sites where downed trees or encroaching vegetation created blockages in the active channel. The work was carried out with permits from the U.S. Army Corps of Engineers, NOAA Fisheries (NMFS), U.S. Fish and Wildlife Service, California Department of Fish and Wildlife, and the Regional Water Quality Control Board. The work will reduce the risk of streambank erosion along riverfront properties.

 

EXHIBITS

20-A    Average Willow and Cottonwood Canopy Rating

20-B    Depth to Groundwater

                       

 

 

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