ITEM:		INFORMATIONAL ITEMS/STAFF REPORTS
33.	QUARTERLY IRRIGATION PROGRAM AND RIPARIAN PROJECTS REPORT
Meeting Date:			January 29, 2009	Budgeted	N/A
From:			Darby Fuerst,	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 resumed in March of 2008 at ten Monterey Peninsula Water Management District (District) riparian habitat restoration sites. The temporary San Carlos system was installed on August 11, 2008 and removed in late November. The following irrigation systems were in use March through November: De Dampierre, Trail and Saddle Club, Scarlett, Begonia, Schulte South, Schulte Bridge, Schulte, All Saints, Valley Hills, San Carlos, and Dow.

Water Use in Acre-Feet (AF)

(preliminary values subject to revision)

January - March 2008 0.01 AF

April - June 2008 2.85

July – September 2008 5.34

October – December 2008 2.26

Total in 2008 10.46 AF

MONITORING OF RIPARIAN VEGETATION: During May through October 2008, staff recorded weekly 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 every week for canopy ratings based on a scale from one to eleven. This scale evaluates characteristics such as yellowing leaves and percentages of defoliation (see scale on Exhibit 33-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. 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 CAW system, the District’s monitoring provides insight into the status of soil moisture through the riparian corridor.

Monitoring results for the 2008 monitoring season show that riparian vegetation experienced moisture stress in some areas. Signs of yellowing and defoliation up to 30% for willows and up to 50% for cottonwoods occurred this fall, but the overall riparian corridor still shows resilience given the critically dry spring. The graphs in Exhibit 33-A and 33-B show average canopy ratings for willows and cottonwoods in selected restoration sites in the lower Carmel Valley and impacts to water table elevations.

The types of monitoring measurements made during May through October 2008 are as follows:

Monitoring Measurement

Canopy Ratings (See Exhibit 33-A for trends.)

Soil moisture (tensiometers)

Groundwater levels (monitoring wells) (See Exhibit 33-B for trends.)

Groundwater pumping (production wells)

OTHER TASKS PERFORMED SINCE THE OCTOBER 2008 REPORT:

1. Vegetation Management at Odello Levee Notch: District Riparian Projects Coordinator Thomas Christensen coordinated with Mission Fields residents and California Department of Parks and Recreation to selectively remove riparian vegetation in a section of the south levee along the Carmel River just downstream of the Highway 1 Bridge known as the Odello Levee.   A notch in the levee was constructed by Monterey County during the 1995 flood season to protect the Mission Fields area from flooding.  This area subsequently became choked with vegetation and debris. Mission Fields residents, whose properties are included in County Service Area 50, were concerned that flood waters would not be able to pass through the notch onto the State Parks-owned area to the south, thereby reducing flooding north of the river. The District was asked to help with this project by the Carmel River Advisory Committee because the District has experience with vegetation management along the Carmel River. Christensen, River Maintenance Specialist Mark Bekker and River Maintenance Worker Matt Lyons, along with State Parks staff and a California Conservation crew, performed the work on November 18.  Cuttings from the notch areas were used for revegetation in the south arm of the Carmel River lagoon.

2. San Carlos Irrigation System: On November 25, 2008, District staff (Christensen, Bekker, Lyons, and Geisler) removed the temporary irrigation system from San Carlos Road Bridge downstream past CAW’s San Carlos Well (1,770 feet). This system is designed to water riparian plants on the bank of the Carmel River to help alleviate moisture stress associated with groundwater pumping. This system was removed because trees had gone dormant for the winter and recent rains have increased soil moisture.

EXHIBITS

33-A Average Willow and Cottonwood Canopy Rating

33-B Depth to Groundwater

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