Ord 1990-014 - Laserfiche WebLink

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2.0 WaRP: PLAN The Health and Safety Plan developed for the previous Ground- Water Assessment project will be utilized for the following tasks. TASK 1 - Well Installation and Development We propose to install three new monitoring wells, the locations of which are shown on Figure 1. Well installation procedures are presented below. The new wells will screen the uppermost water-bearing strata at the site. If the water-bearing strata is under artesian pressure, thawell screen will be confined to the upper portion of the water-bearing strata. If unconfined (water table) conditions are present, the screen will be located to extend partly above and partly below the water table, but would not extend above the potentially water-bearing strata. This will preclude the possibility of providing hydraulic connection between possibly contaminated and uncontaminated zones. Based on currently available information, the "upper Taylor marl" is not a source of ground water, but rather serves to effectively retard the downward movement of ground water and possible contaminants. Provided the site work confirms this to be true, and if the sediments above the "upper Taylor marl" are dry at a given well location, the well will be completed to intercept ground water should it eventually occur in the uppermost permeable sediments. The monitoring wells will be drilled and completed by a drilling contractor licensed to install monitoring wells in Texas. MFG personnel will observe the drilling operations, log the geologic samples and design the wells based on the geologic log. EPA- approved methods and Texas Department of Health guidance will be strictly adhered to during well installation and completion. Detailed geologic logs, well completion forms and construction specifications will be prepared. The wells will be drilled using the hollow stem auger method. Samples will be collected continuously with split-spoon and/or shelby-tube sampling tools in order to accurately describe the stratigraphy in the vicinity of the wells. The soil samples will be described according to ASTM D2488 (Standard Practice for Description and Identification of Soils, Visual-Manual Procedures). Soil samples will be screened fo~ volatile organic carbon's with a portable organic vapor meter'. The pilot holes for the wells will be drilled with 4-1/4 inch ID, 9 inch O.D. augers. If the hole is stable, the augers will be pulled and the well will be installed in the open bore hole. The casing string, centered in the borehole, will be held under 2