WORK PLANS - Laserfiche WebLink

Home Browse Search

� I Ramcon Standard Procedures Standard Procedure 4 Groundwater Monitoring and Sampling Depth-to-Water Measurements Depth-to-water measurements are made with an electric water level gauge made specifically for that purpose. The tape shall be labeled in easily read measurements of no less than 1/100th foot. All materials entering the well bore shall be de-contaminated either prior to site access or on site. In either case the cleaning shall be recorded in the field log or documents specific to that purpose. Prior to site work the relative order of well contamination shall be determined, if applicable to that site. If practical, all wells on the site are accessed and the well caps opened to equilibrate wellbore pressure with ambient atmospheric conditions. Audible indications of well de-pressurization (hissing or gurgling) may warrant extended durations of equilibration time. Well head condition shall be noted on the field forms to document site conditions and notify responsible personnel if repair is warranted. The measuring device is activated and the battery check is tested to ensure operation. The unit is lowered slowly until water is indicated by audible and visual alarms. The unit is raised until the engagement point is determined. This point is carefully indexed to the measuring point on the well riser and the depth to water to the nearest 1/100th foot is read off the measuring tape. The unit is decontaminated and the next well is measured. Well Purging and Recording Groundwater monitoring wells may be purged with either submersible pumps or bailers. If bailers are utilized,they shall be dedicated to that well,or disposable and utilized once only. All reasonable precautions shall be employed to ensure that equipment utilized arrives on site free of substantive hydrocarbon contamination and that during use it does not come into contact with the ground. Disposable Bailers Polyethylene 1-liter capacity disposable bailers (VOSS" or equivalent) are utilized for well purging and sampling. Braided polyethylene disposable rope is utilized with the bailer. Subsequent to each purging and sampling event,the materials are disposed. New rope and a bailer are removed from their sealed packages and purging may begin. Care is taken not to drop the bailer or allow it to free fall to the water surface. Typically, the length to water is determined, and the rope is trimmed to that length plus extra to allow movement. The free end may be secured to a solid object or belt loop to prevent inadvertent loss of the bailer. The cumulative number of bailers purged or the volume is recorded as water is removed until three to four well volumes have been purged. Centrif lgal Puntps Purging pumps must be decontaminated prior to first and each succeeding use. On sites where well order of clean to dirtiest is unknown,a rinsate VOA sample should be collected for possible analysis,if warranted. The pump is lowered into the well bore to several feet off bottom and stabilized at the surface. The pump discharge is readied in such a fashion that representative purge water may be evaluated for stabilization readings and monitoring. When sufficient volume of water has been evacuated the pump may be H:\WPDATA\MIKE\Proceed\4H20.D0C Pa,-,e 2 of