N.H. Admin. Code § Env-Ws 379.11

Current through Register No. 45, November 7, 2024

Section Env-Ws 379.11 - Proposal for Pumping Test Program for Large Production Wells

(a) For all large overburden production wells and for large bedrock production wells with permitted production volumes less than 216,000 gallons, the applicant shall present, in the preliminary report, a detailed proposal for performing either a standard pumping test or an alternate pumping test.

(b) For large bedrock production wells with permitted production volumes equal to or greater than 216,000 gallons, the applicant shall present, in the preliminary report, a detailed proposal for a pumping program that provides data for predicting a sustainable yield and a wellhead protection area on the basis of site specific data and conservative assumptions.

(c) The pumping test program shall be conducted to gather the information necessary to:

(1) Demonstrate that the permitted production volume is sustainable;

(2) Demonstrate that acceptable water quality can be consistently delivered;

(3) Assess impacts to surrounding water resources;

(4) Develop contamination control programs for any known sources of contamination;

(5) Perform the refinement of the wellhead protection area and to justify the selected refinement methodology; and

(6) Demonstrate the system source capacity required by Env-Ws 370-377.

(d) An alternate pumping test shall:

(1) Meet or exceed the requirements of the standard pumping test; and

(2) Be verified, using pumping test data, in the final report as appropriate for site conditions.

(e) A standard pumping test shall meet the following criteria:

(1) The pumping test shall consist of 3 periods, as follows:

a. The antecedent period, during which non-pumping conditions are monitored, starting 7 days immediately preceding the start of pumping;

b. The pumping period, which shall be as follows:

1. For all large overburden production wells, the pumping period shall be for 5 days or until the water level at the pumping well, or at the nearest observation well within 5 feet of the pumping well, has changed less than 0.05 feet in 24 hours, whichever occurs first, except that the pumping period shall not be less than 48 hours in duration;

2. For large bedrock production wells with permitted production volumes less than 216,000 gallons, the pumping period shall be for at least 72 hours; and

3. For large bedrock production wells with permitted production volumes less than 216,000 gallons, the pumping period pumping shall be for 7 days unless, after 72 hours, one of the following conditions exist:

(i) The water level in the pumping well has fluctuated less than 0.05 feet in 24 hours; or

(ii) A theoretical 180-day drawdown does not exceed 90% of the total available drawdown at the time of the test, or 5 feet, whichever is greater, and is derived using the following methodology:

i. Water level data shall be plotted as a semi-logarithmic plot of drawdown versus elapsed time in minutes, with time on the logarithmic axis;

ii. Elapsed time shall be the number of minutes elapsed since pumping began;

iii. A straight line shall be drawn through the data on the semi-logarithmic plot;

iv. The line shall be drawn with a slope based on the data points from the end of the pumping period; and

v. The drawdown indicated by that line for a time of 180 days, or 259,200 minutes, shall be the theoretical 180-day drawdown; and

c. The recovery period, during which the aquifer system recovers from the stress of pumping beginning immediately at shut-down of the pumping well and continuing until the water level in the pumping well or the nearest well within five feet of the pumping well has recovered 95%;

(2) The pumping of and discharge from the test well and the system's other production wells shall be as follows:

a. The pumped water shall be discharged outside the contributing area of operating wells so there is no effect on the aquifer's response to pumping;

b. The pumping rate in the test well shall be recorded at least as often as water level measurements, after the first 10 minutes of pumping;

c. The discharge rate from the test well shall be measured using a circular orifice weir or other device which provides measurements of equal precision;

d. The discharge from other system wells shall be measured using cumulative flow meters;

e. The test well shall be pumped at a single, constant rate that when multiplied by 24 hours produces the proposed permitted production volume in accordance with Env-Ws 379.12; and

f. The system's other wells shall be operated continually, at constant rates during the pumping period unless data is provided which shows these wells will not affect aquifer response to pumping the proposed production well;

(3) Groundwater level measurements shall be made:

a. To the nearest 0.01 foot;

b. At the following locations:

1. The test well;

2. The water system's other production wells;

3. One background monitoring well located outside the expected influence of the test well;

4. For large overburden production wells, at least 4 monitoring wells within the expected area of influence of the test well; and

5. For large bedrock production wells with permitted production volumes less than 216,000 gallons, at such locations as to gather sufficient site specific information such as that obtainable from monitoring wells or geophysical techniques;

c. During the antecedent period, twice daily in the background well, test well and one selected monitoring well, when such wells are used in a pumping test program;

d. During the pumping period, beginning at one minute after the start of pumping until shut down, so that at least 10 data points per log cycle of time in minutes are recorded for the test well and selected monitoring wells; and

e. During the recovery period, beginning at one minute after shut down of the pump until the end of the recovery period, so that at least 10 data points per log cycle of time, in minutes, are recorded for the test well and selected monitoring wells.

(4) Surface water levels in waters within 1000 feet of the pumping well shall be:

a. Collected twice daily throughout the pumping test program;

b. Measured to the nearest 0.01 foot; and

c. Monitored more frequently if the surface water elevation is affected by any dam or other control structure;

(5) Rainfall measurements shall be measured to the nearest 0.1 foot throughout the program at the well site;

(6) If the aquifer is subject to confining conditions, barometric pressure measurements shall be collected throughout the program at the well site;

(7) Site activities and weather conditions shall be observed and logged at the site throughout the program; and

(8) Data analyses and presentation shall include, at a minimum, the following information:

a. A table of the time elapsed since pumping began and;

1. The pumping rate;

2. The recorded groundwater levels;

3. The groundwater levels corrected for other hydraulic influences;

4. The surface water level; and

5. The rainfall data;

b. A daily log of site activity and weather conditions;

c. Plots of recorded and corrected water level data versus time, as log-log and semi-logarithmic graphs, with time plotted on the logarithmic axis, in each of the following formats:

1. Drawdown versus time, with time expressed in minutes of elapsed time, plotted on the logarithmic axis; and

2. Recovery versus time, with time expressed in minutes of elapsed time, plotted on the logarithmic axis;

d. Semi-logarithmic plots of drawdown at the end of pumping versus distance plotted with distance on the logarithmic axis, specifying well names with all data points;

e. For large overburden wells, the analysis and presentation shall also include:

1. Estimates of transmissivity and storage coefficient based on time-drawdown and distance-drawdown plots; and

2. An explanation of the estimating method, presented in the final report, which is based on a comparison of the assumptions underlying the method and aquifer characteristics observed during the pumping test;

f. A plan of the well site constructed as follows:

1. The plan shall be at a scale of one inch equals 100 feet;

2. The plan shall clearly show the locations of all measurements taken;

3. Any surface water in the study area shall be identified;

4. The sanitary protective area shall be shown;

5. Any paths, roadways, structures or other uses inside or adjacent to this area shall be clearly shown and described; and

g. A table of the horizontal distance between observation points and the pumping well.

(f) The proposal for the standard pumping test shall include the following:

(1) The proposed pumping test production rate;

(2) A site sketch showing locations of:

a. Monitoring wells;

b. Surface water staff gauges; and

c. Discharge locations;

(3) A description of and justification for monitoring well layout, construction, and screening;

(4) An outline of borehole drilling and sediment sampling techniques;

(5) A table showing the schedule for monitoring well and surface water level measurements;

(6) A description of the construction of any surface water level staff gages;

(7) The information demonstrating the discharge location is appropriate;

(8) A description of the method and equipment that will be used to ensure a constant pumping rate is maintained;

(9) A schedule for measurement of discharge;

(10) The anticipated operating schedule for nearby wells identified in Env-Ws 379.09;

(11) A description of how any other of the system's wells will be operated while the new well is being tested;

(12) The anticipated pumping test duration and criteria for pump shut down;

(13) The test well construction and screening; and

(14) A description of proposed data analyses and presentation methods.

(g) For all large overburden production wells and large bedrock production wells with permitted production volumes less than 216,000 gallons, an alternative pumping test method is one which differs from the standard method and meets the objectives of the pumping test in accordance with Env-Ws 379.11(c) and the following criteria:

(1) The pumping test provides data necessary for the proposed wellhead protection area delineation method;

(2) The pumping test will produce results which are superior or equivalent to the results obtained using the standard method; and

(3) The pumping test method is justified in the final report based on observations collected during the pumping test program.

(h) The proposal for an alternative pumping test shall include the same material required for the standard under Env-Ws 379.11(f) and information demonstrating the program will meet or exceed the requirements for the standard pumping test.

(i) Additional monitoring wells shall be required when necessary to meet the objectives of the pumping test.

N.H. Admin. Code § Env-Ws 379.11

(See Revision Note at chapter heading for Env-Ws 300) #6521, eff 6-4-97; ss by #6979, eff 4-21-99; ss by #8871, INTERIM, eff 4-21-07, EXPIRES: 10-18-07