New York Codes, Rules and Regulations
Appendix 5-B
Section 5-B.4 - Well yield and water flow

Current through Register Vol. 44, No. 14, April 6, 2022

(a) The purpose of the water well yield test is to provide evidence that a water well will produce a sustainable flow rate for an extended period of time and to quantify that flow rate. Before being put into use, new and redeveloped wells shall be tested for well yield. The yield test for water well flow rates shall meet the following performance requirements:

(1) water well yield tests shall be performed for a period of time adequate to quantify well yield.

(2) water level and flow rate observations shall be made and recorded, at a minimum, before the start of the yield test, immediately upon the cessation of water withdrawal, and periodically during drawdown, and recovery periods. Frequency of measurements shall be made as necessary for the test method.

(3) water discharged during a yield test shall be discharged in a manner that avoids short circuiting of the water back into the aquifer.

(4) for wells that have been subjected to hydrofracturing the yield test shall not commence until redevelopment has been completed and, as a minimum, until the volume of water pumped/discharged into the aquifer has been removed from the well.

(5) the well yield determined for new wells shall be recorded on the Well Completion Report form submitted for that well to the New York State Department of Environmental Conservation. Data generated during the yield test shall be provided to the owner of the well, and provided upon request to the State or local agency(ies) having jurisdiction.

(b) The standard well yield test should include:

(1) A minimum four-hour period of stabilized drawdown while pumping at a constant flow rate.

(2) During the period of stabilized drawdown the stabilized water level shall not fluctuate more than plus or minus 0.5 foot (i.e., within a vertical tolerance of one foot) for each 100 feet of water in the well (i.e., initial water level to bottom of well) over the duration of constant flow rate of pumping. Water level measurement may be determined by steel tape, calibrated pressure gauge attached to an air line terminating at least five feet above the pump intake, electric sounder, or pressure transducer.

(3) The recovery period shall include observation of the water level in the well after cessation of pumping from the drawdown level back to at least 90 percent of the initial water level or for a period of 24 hours, whichever occurs first. If the water level does not recover to 90 percent after 24 hours, the tested flow rate may not be sustainable for an extended period of time.

(c) The well yield test requirements set forth in subdivision 5-B.4(b) may be modified, or an alternative yield test that meets the minimum performance requirements forth in subdivision 5-B.4(a) may be used as follows:

(1) where the local health department having jurisdiction has determine that adequate hydrogeologic information and uniform conditions exist; or

(2) when an experienced hydrogeologist or licensed professional engineer directs and certifies the test; or

(3) for facilities planned for well water use of less than 500 gallons per day, pumping, bailing or air lift test methods may be used,

(4) the well yield of a flowing artesian well may be determined by direct flow measurement if the artesian flow rate equals or exceeds the desired water use rate.

N.Y. Comp. Codes R. & Regs. Tit. 10app 5-B § 5-B.4

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