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Sampling and Analysis Plan (SAP) will be developed for the field activities. All field activities will be conducted using standard Geomatrix field protocols. Analytical services for soil and water chemical analyses will be performed by Precision Enviro-Tech(PET), the Port's contracted analytical laboratory. TASK 1 —DESCRIPTION OF HYDROLOGIC SETTING Geomatrix will conduct a technical analysis of the hydrology of the Roberts Island site. This task will review existing reports and data concerning the surface and subsurface hydrology of the site and will include a site reconnaissance to identify any pertinent hydrologic features that might affect the hydrology of the site. The review will include previous reports written on behalf of the Port for site assessments of nearby dredge placement areas, reports by the Army Corps of Engineers (ACOE) regarding dredge placement sites on Roberts Island, and published reports on the hydrology and hydrogeology of Roberts Island and/or nearby delta lands (including Rough and Ready Island and the Port of Stockton). The deliverable for this task will be a description of the hydrologic setting including regional surface water(rivers, sloughs, canals, drainageways), groundwater(stratigraphy, groundwater occurrence, water quality, and usage), and groundwater/surface water interactions. TASK 2—EVALUATION OF VADOSE ZONE This task will provide the background data needed to evaluate the ability of the existing soils to mitigate potential releases of dissolved metals and other constituents in the dredged material. Five soil borings will be drilled across the 40-acre disposal site (Figure 1). Each boring will be advanced, using a hollow-stem auger rig, until the boring reaches the water table (estimated to be within about 10 feet of the surface). Continuous core samples will be taken using a sleeved, split-spoon sampler. Samples will be collected where significant breaks in lithology are noted. It is estimated that three samples per boring will be submitted for physical analysis (grain size and permeability), and four samples per boring will be submitted for chemical analysis (pH, cation exchange capacity, and organic carbon content). The physical analyses will be done to provide a relative measure of the hydraulic conductance of the vadose zone. Although infiltrometer testing was recommended by the RWQCB,when the dredge materials are introduced onto the surface, the surface infiltration capacity will be significantly changed from pre-placement conditions and reduce the quantitative value of the infiltrometer tests. We believe the physical testing will provide sufficient information to estimate the amount of water JAMARKET\PROPOSAL\2000 Props\6988-POS\Amended work plan.doc 2