ITEM: INFORMATIONAL ITEMS/STAFF REPORTS
29. QUARTERLY IRRIGATION PROGRAM AND RIPARIAN PROJECTS REPORT
Meeting Date: January 30, 2003 Budgeted: N/A
Program/Line Item No.: N/A
Staff Contact: Thomas Christensen Cost Estimate: N/A
General Counsel Approval: N/A
Committee Recommendation: N/A
IRRIGATION OF RIPARIAN VEGETATION: This quarterly report is for the period October through December 2002. The supplemental watering of riparian restoration plantings ceased at the end of October. The following irrigation systems were irrigated during this period: DeDampierre, Scarlett, Begonia, Schulte South, Schulte Bridge, Schulte, All Saints, Valley Hills, and San Carlos. Quarterly and annual totals for 2002 are as follows:
Water Use in Acre-Feet (AF)
January - March 2002 0.02 AF
July - September 2002 4.24
October – December 2002 1.82
MONITORING OF RIPARIAN VEGETATION: During the month of October 2002, 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 (San Carlos, Valley Hills, Schulte, and Cañada) 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 gypsum blocks and tensiometers. Soil moisture values are measured at seven stations with 18-inch and 36-inch tensiometers paired with gypsum blocks set at 18 inches and 36 inches 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.
Current results for the 2002 monitoring season showed that riparian vegetation experienced increased levels of moisture stress associated with groundwater pumping and warm summer temperatures. 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 following graphs show impacts to water table elevations and riparian moisture stress in selected restoration sites in the lower Carmel Valley. Starting November 1, 2002, monitoring of riparian vegetation is suspended until May 2003 because there is sufficient soil moisture for maintenance and growth of the vegetation.
The type of monitoring measurements made during May through October 2002 are as follows:
Dawn leaf water potential (See Exhibit 29-A for trends.)
Soil moisture (gypsum blocks)
Soil moisture (tensiometers)
Groundwater levels (monitoring wells) (See Exhibit 29-B for trends.)
Groundwater pumping (production wells)
OTHER TASKS PERFORMED SINCE OCTOBER 21, 2002 REPORT:
1. Field Tour for University of California Berkeley (UCB) Class: On September 22, 2002, District staff (Christensen and Hampson) gave a tour of District restoration projects to students in a UCB graduate course on river restoration. This is an annual event associated with a class emphasizing restoration techniques and design taught by Dr. Matt Kondolf.
2. U.S. Fish and Wildlife Service (USFWS) Authorization: On October 11, 2002, Dawn Reis, a consultant knowledgeable about California red-legged frogs (CRLF), trained District staff in identifying, handling, and relocating CRLF encountered in the conduct of District activities. After completion of this training, the USFWS authorized several District staff members to monitor for CRLF and to move frogs when construction and other activities are conducted along the river.
3. San Carlos Irrigation System: District staff removed the temporary irrigation system in the area of Cal-Am’s San Carlos Well on November 15, 2002. This system is designed to offset moisture stress on riparian vegetation associated with groundwater pumping during periods of little or no river flow.
4. Carmel Middle School Outreach: District staff (Christensen and Wheeler) met with Craig Hoenberger of Carmel Middle School on November 26, 2002 to talk about a student willow and cottonwood planting project on Carmel Middle School property. Students will take cuttings from cottonwoods and willows and plant them in spring and fall 2003.
5. Carmel River Flow Threshold Report, Jones, Stokes and Associates (JSA): District staff worked closely with JSA to assist in preparation of the Threshold Report. Staff compiled District data to allow the consultant to make conclusions with regards to instream flows necessary to support steelhead and riparian vegetation in the Carmel River.