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1 5. The Contractor shall run clean water continuously down the gravel-fill pipe during the operation and add gravel as needed. 6. The Contractor shall bail or air lift sediment from the bottom of the well as required. 7. It is anticipated that the air-lift swab development shall continue for approximately 60 hours for each well or until all sand and mud have 16 { been washed through screened sections of the well to the satisfaction of the City. Upon completion of this procedure, the well shall again be bailed or air lifted clean of all accumulated sediment to its full depth. F. Development with Test Pump (Surging and Pumping): 1. After completion of well development using the air-lift swab, the Contractor shall commence well development using a test pump. The �p test pump shall be capable of pumping up to 4,000 gpm and be [[ equipped to throttle flow between 500 and 4,000 gpm for the Production Well, and between 4 and 30 gpm for the Nested Monitoring Well. 2. The quantity of water being pumped from the well at commencement of 5 development pumping shall be limited and gradually increased as the water clears. From time to time, the pump shall be stopped and the water in the pump column allowed to flow back through the pump bowls and through the screened sections into the aquifers. This procedure, ` with increasing pumping rates, shall be repeated as development of the well continues and shall be done in a manner satisfactory to the City. This procedure shall be repeated at approximately 250 gpm increments up to 4,000 gpm for the Production Well and at 2-gpm increments up to 30 gpm for the Nested Monitoring Well. 3. Development of the well shall be continued for approximately 48 hours or until the specific capacity has been maximized and the well produces not more than 5 parts per million of sand by volume 15 to 20 minutes after surging at a pumping rate of at least 2,500 gpm for the Production Well and 20 gpm for the Nested Monitoring Well. The achievement of proper well development will be judged by the City based upon examination of pumped water samples. During the test, the rate of sand production shall be measured by the Contractor using a Rossum-type tester (Journal of American Water - Works Association, Volume 46, No. 2, February 1954). The Rossum- type tester shall be furnished by the Contractor. The results of all sand production tests shall be expressed in parts per million at 5-minute intervals and shall be provided to the Engineer immediately. The final sand production test shall be conducted in the presence of the Engineer. 5. Clean water shall be added continuously down the gravel fill pipe during development. 6. If, during the development operations, there is any indication of _ settlement of the gravel pack, more gravel shall be added as needed and the quantity recorded and reported to the Engineer. 7. After completion of development pumping, the Contractor shall clean the l well of all accumulated sediment and foreign material prior to running the well production and aquifer tests. Division III-27