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APPENDIX H <br />' GROUNDWATER MONITORING WELL DEVELOPMENT PROCEDURES <br />' INTRODUCTION <br /> Newly installed groundwater monitoring wells will be developed to <br /> restore natural hydraulic conductivity of the formation, remove <br />' sediments from well casing and filter pack, stabilize the filter <br /> pack and 4quifer material , and promote turbidity-free groundwater <br /> samples . <br />' Wells may be developed by bailing, hand pumping, mechanical <br /> pumping, air lift pumping, surging, swabbing, or an effective <br /> combination of methods . Wells will be developed until the water <br />' is free of sand, silt, and minimum turbidity has stabilized. <br /> In some cases where low permeability formations are involved or <br />' the drilling mud used fails to respond to cleanup, initial <br /> development pumping may immediately dewater the well casing and <br /> thereby inhibit development. When this occurs, clean, potable <br />' grade water may be introduced into the well , followed by surging <br /> of the introduced waters with a surge block . This operation will <br /> be followed by pumping . The procedure may be repeated as <br /> required to establish full development. <br /> METHODOLOGY <br />' Seal Stabilization. Cement and bentonite annular seals shall set <br /> and cure not less then 72 hours prior to well development . <br />' Decontamination • All well development tools and equipment shall <br /> be thoroughly cleaned immediately before starting each well <br /> installation. When available, each component shall be cleaned <br />' with a high temperature, high pressure washer for a minimum of 5 <br /> minutes. When a washer i5 not available, components shall be <br /> cleaned with clean water, then rinsed with distilled water. <br />' Development equipment shall not donate to, capture, mask, nor <br /> alter the chemical composition of the soils and groundwater. <br />' Introduction of Water: Initial development of wells in low <br /> permeability formations may dewater the casing and filter pack. <br /> When this occurs, clean, potable water will be introduced into <br /> the well to enhance development <br /> Bailing: Development will begin by bailing to remove heavy <br /> sediments from the well casing . Care will be taken to not damage <br /> the well bottom cap during lowering of the wailer. <br /> r <br />