ITEM:

INFORMATIONAL ITEMS/STAFF REPORTS

 

26.

QUARTERLY IRRIGATION PROGRAM AND RIPARIAN PROJECTS REPORT

 

Meeting Date:

January 26, 2006

Budgeted

N/A

 

From:

David A. Berger,

Program/

N/A

 

General Manager

Line Item No.:

 

Prepared By:

Thomas Christensen

Cost Estimate:

N/A

 

General Counsel Approval:  N/A

Committee Recommendation:  N/A

CEQA Compliance:  N/A

 

IRRIGATION OF RIPARIAN VEGETATION: The supplemental watering of riparian restoration plantings was conducted in 2005 during the months of May through November at nine Monterey Peninsula Water Management District (District) riparian habitat restoration sites.  The following irrigation systems were in operation:  DeDampierre, Trail and Saddle, Scarlett, Begonia, Schulte South, Schulte Bridge, Schulte, Valley Hills, and All Saints. However, it should be noted that an error discovered in the meter readings for the Schulte Bridge system has been corrected. Therefore, the two previous Water Use calculations for the quarterly reports were not accurate. The correct water use for the year is in the table below.

 

            Water Use in Acre-Feet (AF)

            January - March 2005              0.00 AF

            April - June 2005                     1.30

            July - September 2005             3.88

            October – December 2005       1.12

            Total in 2005                            6.30 AF

 

MONITORING OF RIPARIAN VEGETATION:  During the months of May through October 2005, staff took weekly measurements of leaf water potential 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 twice a month for pre-dawn leaf water potential.  A total of 14 willows and 13 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.  Soil moisture measurements are conducted at three of these sites (San Carlos, Valley Hills, and Schulte) using tensiometers.  Soil moisture values are measured at seven stations with 18-inch and 36-inch tensiometers in the soil column.  Combined with monthly readings from the District’s array of monitoring wells and pumping records for large-capacity Carmel Valley wells in the Cal-Am system, the District’s monitoring provides insight into the status of soil moisture through the riparian corridor.

 

 

Monitoring results for the 2005 monitoring season show that non-irrigated sample willows at Valley Hills became severely stressed in late September. Sample trees are not irrigated intentionally to see how they respond in a natural setting.  Willows are considered severely stressed when values are 7.5 bars and above, while cottonwoods are considered severely stressed when values are 10.0 bars and above. The graphs in Exhibit 26-A and Exhibit 26-B show impacts to water table elevations and riparian moisture stress in selected restoration sites in the lower Carmel Valley.

 

The types of monitoring measurements made during May through October 2005 are as follows:

 

            Monitoring Measurement                                        

 

            Dawn leaf water potential                                  (See Exhibit 26-A for trends.) 

            Soil moisture (tensiometers)                                         

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

            Groundwater pumping (production wells)                     

           

 

 

OTHER TASKS PERFORMED SINCE SEPTEMBER’S 2005 REPORT:

 

1.         In-Channel Vegetation Management: During the beginning of October, District staff (Christensen, Dettman, Hamilton, Lyons, Rymer, and Bekker) completed the selective removal of vegetation at four sites along the Carmel River.  This work helps prevent erosion when vegetation and debris dams deflect high flows away from the center portion of the channel into the streambanks. Staff obtained the necessary permits from federal and state agencies.  The project consisted of work at the following four locations.

 

(1) Beginning at Robles Del Rio Bridge at River Mile (RM) 14.5 and extending approximately 95 feet downstream.  Only the largest trees growing on a mid-channel island were removed. The large trees were placed in the flowing stream to provide large wood habitat. The remaining trees were left for shade and cover based on field visit discussions with the California Department of Fish and Game (CDFG).

 

(2) Beginning at approximately RM 11.8 near the east end of Garland Park and extending approximately 80 feet downstream along the Sutherland property.  A section of riparian vegetation was removed to allow debris to pass this section of the main channel because of recent erosion just upstream.

 

(3) Beginning approximately two miles upstream of the Robinson Canyon Road Bridge by Ronnoco Road (RM 10.1), and extending approximately 345 feet downstream.  The top, middle, and end sections of an overflow channel, as well as two sections in the main channel, were opened up to allow debris and high flows to pass.

 

(4) Beginning about ¼ mile upstream of Via Mallorca Bridge(RM 3.5) and extending 70 feet downstream adjacent to the Hacienda Carmel Community Association property.  Vegetation causing a mid-channel gravel bar and debris pile was removed because of recent erosion just upstream.

 

2.         Participation in Coastal Training Program:  District staff (Thomas Christensen and Larry Hampson) participated in a training program focusing on the Carmel River watershed held by the Elkhorn Slough Coastal Training Program on November 3 and 4, 2005.  Thomas and Larry spoke on the District’s environmental protection and habitat restoration programs on the Carmel River.             

 

EXHIBITS

26-A    Average Dawn Leaf Water Potential

26-B    Depth to Groundwater

 

 

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