ITEM:

INFORMATIONAL ITEMS/STAFF REPORTS

 

26.

QUARTERLY CARMEL RIVER RIPARIAN CORRIDOR MANAGEMENT PROGRAM REPORT

 

Meeting Date:

January 24, 2018

Budgeted:

N/A

 

From:

Dave Stoldt,

Program/

N/A

 

General Manager

Line Item No.:

 

 

Prepared By:

Thomas Christensen and

Cost Estimate:

N/A

 

Larry Hampson

 

 

                            

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 resumed for the summer season in 2017 at six Monterey Peninsula Water Management District (District) riparian habitat restoration sites.  The following irrigation systems were in use May through November: deDampierre, Trail and Saddle Club, Begonia, Schulte, Dow, and Schulte Bridge.

 

            Water Use in Acre-Feet (AF)

            (preliminary values subject to revision)

           

            January - March 2017             0.0 AF

            April - June 2017                    1.39

            July – September 2017           5.22

            October – December 2017      1.59 AF

           

            Year-to-date                            8.20 AF

 

MONITORING OF RIPARIAN VEGETATION:   Starting in June 2017, 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 26-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 2017 season show that riparian vegetation was below threshold moisture stress levels.  This was due to the fact that the Carmel River flowed all year to the lagoon and provided plenty of water for established plants along the riparian corridor. The graph in Exhibit 26-A shows average canopy ratings for willows and cottonwoods in selected restoration sites in lower Carmel Valley.  The graph in Exhibit 26-B shows impacts to water table elevations.

 

The types of monitoring measurements made during June - October 2017 are as follows:

 

            Monitoring Measurement                                       

 

            Canopy ratings                                                (See Exhibit 26-A for trends.)          

            Groundwater levels (monitoring wells)          (See Exhibit 26-B for trends.)          

            Groundwater pumping (production wells)

 

OTHER TASKS PERFORMED SINCE THE OCTOBER 2017 QUARTERLY REPORT:

 

1.                  Carmel River Mitigation Plantings: During the months of November and December, District staff  have been planting riparian trees along the Carmel River to mitigate for in channel Vegetation Management activities where downed trees or standing vegetation created blockages in the active channel. This work is carried out with permits from the U.S. Army Corps of Engineers, NOAA Fisheries, U.S. Fish and Wildlife Service, California Department of Fish and Wildlife (CDFW), and the Regional Water Quality Control Board. The goal of the vegetation management activities is to reduce the risk of streambank erosion along riverfront properties where vegetation encroachment could potentially divert river flows into streambanks during high flow periods.

 

2.                  Instream Flow Incremental Method Study: MPWMD fisheries staff collected additional data from the river channel about fish presence and effects of winter storms, which filled many of the deep pools with sand.  The District’s Consultant (Normandeau Inc.) will test whether these changes  significantly affect steelhead habitat.  A final IFIM report and memo on changes in channel conditions should be available in the 4th quarter of 2017.

 

3.                  Los Padres Dam Long-Term Plan:  The first Technical Review Committee (TRC) meeting was held on August 3, 2017.  For a dredging operation, the Consultant team recommended against using steep canyon areas upstream of the reservoir for placing dredged material and instead determined that all material presently within the reservoir could be placed on Cal-Am property downstream of the existing dam.  It was estimated that an average of 16,000 to 34,000 cubic yards of material per year accumulates in the reservoir (about 32,000 to 68,000 tons).

 

For a reservoir expansion alternative, options include installing a temporary rubber dam or permanent dam raise, a new dam downstream or a combination.   For a dam removal alternative, phased (multi-year) removal by elevation was deemed not feasible because an operating spillway would be required after each removal.  Partial or full removal of the embankment is feasible if the reservoir is to be abandoned.

 

The Consultant will refine alternatives before convening the second TRC meeting in January, which will focus on evaluating alternatives.

 

4.                  Los Padres Dam Fish Passage Study:  The Consultant team presented a preliminary ranking of passage alternatives showing a retrofit or replacement of the existing trap and truck operation as the highest ranked alternative for upstream passage.  The highest ranked alternatives for downstream passage were a floating surface collector placed at    the head or reservoir or at about mid-reservoir to capture downstream migrating fish and transport them to the dam. The Technical Review Committee was asked to comment on evaluation criteria and rankings.

 

5.                  Stormwater Resource Plan (SRP): Staff participated in the first Technical Advisory Committee meeting to develop the Stormwater Resource Plan and provided requested information to the consultant team developing the plan.  The focus of the SRP is to identify sources of stormwater throughout the Monterey Peninsula that can be recycled as new water supply.

 

EXHIBITS

26-A    Average Willow and Cottonwood Canopy Rating

26-B    Depth to Groundwater

                       

 

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