ITEM:

INFORMATIONAL ITEM/STAFF REPORT

 

15.

QUARTERLY CARMEL RIVER RIPARIAN CORRIDOR MANAGEMENT PROGRAM REPORT

 

Meeting Date:

October 17, 2022

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 May through September: Sleepy Hollow, deDampierre, Trail and Saddle Club, Begonia, Schulte, Valley Hills, and San Carlos.

 

            Water Use in Acre-Feet 2022 (AF)

            (preliminary values subject to revision)

            January - March          0.20 AF

            April - June                 0.70

            July – September        3.12

            Year-to-date                4.02 AF

 

MONITORING OF RIPARIAN VEGETATION:   Starting in June 2022, staff recorded monthly 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 monthly 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 15-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 2022 monitoring season to date show that riparian vegetation is experiencing moisture stress levels associated groundwater extraction and the lack of rainfall. It is important to note that irrigation around municipal wells is carried out to help alleviate impacts from water extraction. The graph in Exhibit 15-A shows average canopy ratings for willows and cottonwoods in selected restoration sites in lower Carmel Valley.  The graph in Exhibit 15-B shows impacts to water table elevations. The types of monitoring measurements made during June through September are as follows:

 

            Monitoring Measurement                                       

            Canopy ratings                                                (See Exhibit 15-A for trends.)          

            Groundwater levels (monitoring wells)          (See Exhibit 15-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 five 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

15-A    Average Willow and Cottonwood Canopy Rating

15-B    Depth to Groundwater

                       

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