The pump test procedure for new wells shall consist of:
1) A Step-Drawdown Test (for proposed permanent pump capacity ≥ 70 gpm) to assess individual well performance with regard to yield and sensitivity to chloride changes and nearby aquifer properties followed by:
2) A Constant-Rate Test (for proposed permanent pump capacity > 50 gpm) to further assess nearby hydraulic properties of the aquifer Please refer to the Hawaii Well Constructions and Pump Installation Standards for more detailed instruction and discussion of required pump test procedures.

Step-Drawdown Test
1. Measurement of water level in the pumped well shall be made at 15-minute intervals for 45 minutes prior to the initiation of the step-drawdown test in order to obtain the pretest static water level.
2. The step-drawdown test will consist of continuously pumping the well at progressively increasing fractions of the proposed discharge at a minimum of 3 rates.
a. The minimum length of time for each discharge rate shall be ½ hour and dependent on the occurrence of an observable change in water level in the well from the previous pumpage rate.
b. The test shall begin with the lowest pumping rate and conclude with the highest rate.
3. As a minimum, a water sample taken at the end of the test shall be tested for chloride content.

Constant-Rate Test
1. The long-term test should not commence until the water level in the pumped well has fully recovered from the step-drawdown test. The static water level in the pumped well shall be measured at 15-minute intervals for 45 minutes.
2. The pump rate for the long-term test shall be an amount as determined by the step-drawdown test or equal to the proposed pump capacity.
3. The test should be run in accordance with Table 9 in the Hawaii Well Construction and Pump Installation Standards.
4. Measurement of chloride concentration and temperature of the discharge water during the long-term test shall be made at the beginning of the test and every six hours thereafter.
5. Depth to water in all wells shall be measured at intervals of 10 minutes or less during the first 2 hours of pumping, at intervals of 1 hour or less to the 24th hour, and at an interval of 2 hours or less for the remainder of the required test period.
6. A sufficient number of water level measurements shall be made in the pumped well following termination of the long-term continuous test to establish water-level recovery. Immediately upon termination of the test, the depth to water in the pumped well shall be measured at a frequency that corresponds to the pattern required during the pumping period and for such a period of time required for the water level in the well to recover to within 80% of the water level observed at the beginning of the test.

For the pumping test, at least three bores are to be installed, one as abstraction/pumping bore and two observation bores.

The advantages of the pumping test are probably self-evident (Freeze and Cherry, 1979). A pumping test provides in-situ parameters of aquifer, and these parameters are averaged over a large and representative aquifer volume.

Disadvantages of practical and theoretical. In terms of practical disadvantage of the method lies in its expense, and theoretical relates to the nonuniqueness of pumping-test interpretation.

The screen must fully penetrate the aquifer, which means the top of screen must be over the water level to prevent potential vertical gradient.

What distances do you use between the pumping bore and observation bores?