FIELD DOCUMENTS - Laserfiche WebLink

Home Browse Search

Y Wright Environmental Services, Inc. Monitoring Well Development 1 . Wells will be developed until the water is free of fine grained sediments and/or until field measurements of pH, and electrical conductivity have stabilized. Approximately 3 to 10 well volumes of water will be removed during development of the well. The actual number of volumes withdrawn for development i$ well dependent and based on the field judgment. Duration of development will be specific for each well and site aquifer conditions and continue until the water clears and sand content is minimal or ceases. Measurements of aquifer parameters may be taken to observe for aquifer conditions. Notes of well development will be kept including quantity of water removed, turbidity, and sand yield and well recharge. 2. Only precleaned equipment will be inserted into the well during development, and will be decontaminated by washing or steam cleaning after its use. Development water will be collected and stored in in drums. Monitoring Well Sampling 1 . Depth to groundwater will be measured to the nearest 0.01 foot, and the well checked for presence of separate phase product. If present, the apparent thickness of the product will be measured. The well will not be sampled if separate phase product is present. 2. The standing well volume calculated, and usually between 3 to 10 well volumes will be purged from the well prior to sampling depending on well performance and yield (USEPA (1985) sampling guidance indicates that the number of purge volumes are related to aquifer strata and specific for each well). Measurements of aquifer parameters (conductivity, temperature and the pH) of the water will be taken until parameters have stabilized to indicate that aquifer water is entering the well over at least two purge volumes. The sampler will keep field notes for each well sampled. That field log will record sampling measurements and observations. Aquifer parameters which will be measured are; pH, temperature and electrical conductivity. Aquifer water is assumed to be entering the well when these parameters are measured within a 10% range of the previous measurements. The sample will be collected when the well recovers to within 80% of the original depth to water measurement. 3. The groundwater samples may be collected using a Teflon® or disposable bailer or sampling pump discharge. Sampling gear will be thoroughly steam-cleaned or cleaned with soapy (TSP) water, rinsed with with deionized or distilled water prior to the collection of each sample. When bailers are used, a separate clean bailer will be used to sample each individual well. Wes Sampling Protocols last rev. 2/96 Page 5