Laserfiche WebLink
U <br /> 4.6. PERFORATIONS <br /> 4.6.1. The perforating of casing shall not deform the casing. The casing shall not be <br /> perforated within fifty (50) feet of the ground surface if the total depth of the well is <br /> greater than fifty (50) feet. The upper most perforation shall be below an impervious <br /> stratum in an aquifer of good quality water. <br /> 4.6.2. .If a well with perforations fifty (50) feet deep or less from the ground surface is <br /> deepened, the perforations fifty (50) feet deep or less shall be sealed off to prevent <br /> commingling with water in a deeper aquifer of good quality. <br /> 4.7. WELL GROUTING AND CONSTRUCTION <br /> The primary purpose is to prevent contamination, pollution and degradation of water wells and <br /> of the ground water by intrusion of poor quality water and cross contamination of aquifers. <br /> 4.7.1. The annular space between the well casing and the wall of the drilled hole, or between <br /> the conductor pipe and the wall of the drilled hole, or the well casing shall be filled <br /> i with approved cement grout or bentonite clay, or other sealant material approved by <br /> I the Director, from the ground surface into an impervious formation under-laying the <br /> uppermost aquifer. If an impervious formation sloes not exist, the annular space shall <br /> be filled to a sufficient depth to prevent polluted or contaminated water from entering <br /> the well. The minimum depth of the annular seal shall be as follows: <br /> Public Water supplies-------- ---- -- 1008 <br /> Individual Domestic Wells----- ------- 100& <br /> Industrial Wells - --------------- 100& <br /> Agricultural Wells --- --- -- -- ----- 50 R. <br /> 4.7.1.1. Local conditions will determine depth of seal. Any deviation from <br /> Ordinance requirements will require, a Special Water Well Permit. <br /> 4.7.2. Gravity installation of sealing material, without the aid of tremie or grout pipe is <br /> prohibited unless the interval to be sealed is dry and in no case where the interval is <br /> over 30 feet in depth. <br /> 4.7.2.1. In placing the annular seal, a tremie pipe shall be installed within 5 feet of <br /> the desired seat depth and removed as the grout is installed. <br /> 4.7.3. Sealing Material: <br /> 4.7.3.1. Neat Cement - 1 bag (94 lbs.) Portland Cement to 5 to 10 gallons of <br /> potable water. <br /> 4.7.3.2. Cement Grout - Not more than two (2) parts by weight of sand and one (1) <br /> part by weight of cement (per bag of cement) to 5 to 7 gallons of potable <br /> water. <br /> 4.7.3.3. Bentonite-sealing materials and their uses shall be in accordance with the <br /> manufacturers specifications or as approved by the Director. <br /> 4.7.3.4. Quick setting type cement, retardants to setting, bentonite, or other <br /> additives, may be used not to exceed 5% of the volume. Hydrated lime <br /> may be used up to 10% of the volume. <br /> 4.7.4. In grouting the annular space, the grout shall.be.applied in one continuous process. <br /> Deviations from this process may be approved on a site specific basis by the <br /> Director. The annular seal shall have a minimum width thickness of two (2) inches. <br /> 4.7.5. No repair or deepening of a well shall be done without prior approval from the <br /> Director. <br /> 4.7.5.1. Each well will be evaluated on a site specific basis to determine the <br /> feasiblity of the work desired. <br /> 9 <br />