Artesian Flowing Wells Field of Phu Tok Aquifer

Phu tok Aquifer is the most productive water bearing rock in the Northeastern region of Thailand. Generally, well drilled in this aquifer yields approximately 20–50 m3/hr with some wells yield over 150 m3/hr. This aquifer characterized both unconfined and confined aquifer. Data collected from core sampling and TV bore hole show water bearing fractures in the fine grained massive sandstone intercalated with thin shale layers. These intermittently bedding plane fracture zones were found vertically at 60-65 and 95-110 m below ground surface. Three directions of vertically fractures were also found at 103-104 m in the test well with underlain densely sandstone until 120 m of depth. Wells drilled to 60-70 m fractures at the area where surface elevation between 150 and 170 m above mean sea level were artesian well with rising water about 1-3 m. Natural discharge rate from 2-5 inches of diameter casing is 5-10 m3/hr. Fractures at 90-110 m yield 150 m3/hr through 6 inch casing well with 5-6 m of risen water above the ground. It is found from pumping test of Phu Tok Aquifer that hydraulic conductivity of unconfined aquifer at shallower than 50 m is 0.005-17 m/d. Transmissivity and storage coefficient are 0.05-20 m2/d and 7×10-3-0.725 respectively. The confined aquifer at depth not exceed 90 m has hydraulic conductivity value of 0.2-10 m/d while transmissivity and storage coefficient are 3.19-150 m2/d and 1×10-10-1.6×10-2. Another confined aquifer at 90-120 m of depth have hydraulic conductivity value of 0.08-15 m/d and transmissivity and storage coefficient values of 1.7-178 m2/d and 4×10-7-4.5×10-3 respectively.