WORK PLANS - Laserfiche WebLink

Home Browse Search

KOPPEL-STOCKTON TERMINAL MONITORING WELL ABANDONMENT AND CONSTRUCTION WORK PLAN source of nitrate upgradient(north or northwest) from Koppel. Potential sources include leaching from the ponding area north of Koppel or historical practices at Cal-Farm and PM Ag Facilities. During the last sampling event,Monitoring Well KP-10S was never located;however,it is assumed to be damaged. Abandoning and replacing this monitoring well is recommended. The replacement well (Monitoring Well KP-10S-R)will continue to monitor upgradient sources of nitrate concentrations migrating onto Koppel and will be the northernmost well located at Koppel (see Figure 1). 2.3 Monitoring Well KP-BG-1 Monitoring Well KP-BG-1 was considered the background well for the site and is located adjacent to a railroad spur, on a vacant lot.During a site visit conducted in September 2009, it was determined that the well was filled with debris up to the water level(approximately 5 feet below ground surface) and could not be repaired. It appeared that the well had been damaged by a combination of construction activities and vandalism(CH2M HILL,2009). Ammonia has never been detected (1999 to 2009) and nitrate has been detected at very low concentrations ranging from 11.3 to 40.3 mg/L. Although Monitoring Well KP-BG-1 was considered the background well for the site,it is not representative of upgradient nitrate concentrations that are migrating onto Koppel from the north. Additionally,a sufficient amount of data has been collected to characterize nitrate and ammonia concentrations near KP-BG-1. Abandoning Monitoring Well KP-BG-1 is recommended,however replacing this well is not recommended.The proposed replacement Monitoring Well KP-10S-R and existing Monitoring Well KP-12S will serve as background wells (see Figure 1). Details regarding drilling,well abandonment and construction,development,and sampling of monitoring wells KP-IOS-R and KP-4D are provided in the following sections. 3.0 Well Drilling Procedures Monitoring wells to be abandoned (Monitoring Well Pair KP-5S and KP-5D and Monitoring Wells KP-BG-1 and KP-10S) and the proposed well locations (Monitoring Wells KP-10S-R and KP-4D)are shown on Figure 1. Access agreements are being obtained or updated with the current property owners,BNSF Railroad,Headwater Resources, and the Port of Stockton,to facilitate abandonment and construction of wells. Well destruction and construction permits will be obtained from San Joaquin County prior to drilling. Utility clearance will be obtained by contacting Underground Services Alert prior to drilling.In addition,the existing site-specific health and safety plan will be reviewed prior to fieldwork and updated if necessary. Hollow-stem augers with a 10-inch inner diameter will be used to advance the boreholes. The boreholes will be sampled and logged at 5-foot intervals.Soil cuttings will be collected in bins during drilling and spread on the surface of the northern planting location.Well development water will be used to irrigate the trees in the various planting areas. RDM102300006(CLR4507.DOCX) 3 E9NWIMMNRDD