The following values for a confined aquifer are measured from the ground surface: depth to piezometric level before pumping = 25 ft depth to top of aquifer = 75 ft depth to bottom of aquifer = 125 ft. A 24-inch diameter well is driven to the bottom of the aquifer an pumped at 500 gpm until steady state conditions are attained. The drawdown at an observation well 50 ft from the pumping well is 10 ft and the drawdown at an observation well 100 ft from the pumping well is 5 ft.
(a) Make a sketch that clearly defines the problem.
(b) Determine the hydraulic conductivity and transmissivity
(c) Determine the drawdown at the well.
(d) Determine the distance from ground level to the piezometric level at the well.
Hydraulic conductivity of confine aquifer can be calculated by Thiems equation
Transmissivity T = KB
The following values for a confined aquifer are measured from the ground surface: depth to piezometric...
A well is constructed in a confined aquifer. The aquifer has a uniform thickness of 50 ft overlain by a aquitard and the bottom is 115 ft below ground surface (bgs). A pumping test weas used to determine the hydraulic conductivity of the aquifer. The initial piezometric (potentiometric) surface of the confined aquifer was 49 ft bgs at the pumping well and the observation wells. After water was pumped at a rate of 0.46 cu ft/sec for several days, the...
(Q4). For the confined aquifer shown in the figure, find the hydraulic conductivity, K and transmissivity, Tif the pumping rate from the well (Q) is 250 gpm. The thickness of the confined aquifer is 75 ft. The draw down at a distance of 50 feet away is 8 feet and the drawdown at a distance of 200 feet away from the well is 2 ft. The original piezometric head (h.) is 100 feet from top of the shale surface as...
An aquifer test with a constant pumping rate of 200 gpm was conducted in a confined aquifer with a saturated thickness of 12 m. Head measurements in an observation well located 76.2 m (250 ft) from the pumping well yields the following plot. Use the Cooper-Jacob (1946) straight-line method to compute transmissivity [m/d], hydraulic conductivity [m/d and m/s], storativity and specific storage m ] of the aquifer 0 0.2 0.4 0.6 0.8 1.2 0.1 10 100 1000 Time (min) An...
Question 5: (25 marks) A fully penetrating pumping well is located in a confined aquifer that can be considered to have an infinite extent in all directions. There is no recharge to the aquifer and no other pumping wells in the area. There are two observation wells located at 100 and 500 m, respectively, from the pumping wells. The aquifer and the pumping well have the following properties: Depth to top of aquifer: 50 m Aquifer thickness: 5 m Aquifer...
1. (2 points) A well in a uniform, homogeneous, isotropic confined aquifer is pumped at a rate of 815 L/min. After 3 days it looks as if the water levels have stabilized in observation wells at distances of 20 m and 200 m from the pumping well. The drawdown in the well at 20 m is 6.5 m and the drawdown in the well at 200 m is 3.5 m. a) Use the Thiem solution to determine the aquifer transmissivity....
An unconfined aquifer has an initial thickness of 15.80 m. The initial water table is horizontal and located 4.7 m below the ground surface. A 15-cm diameter well is driven to the bottom of the aquifer and pumped at 3000 Lpm until steady state conditions are achieved. At this time the drawdown at the well is 4.35 m and the drawdown in an observation well located 850 m away is 0.12 m. (a) Make a sketch that defines the problem....
The drawdown doserved at a confined aquifer well after pumping it during 1400 minutes at a flow rate of 500 gal/min is 20.39 ft. The drawdowns observed at the same time at two observation wells located at 10 ft and 100 ft from the pumped well are 20 and 19.7 ft, respectively. Find the transmissivity of the aquifer and the well radius. Answ: T-8.8x105 gpd/ft, r-0.5 ft. 3.
please explain the answer for part D. 6.124pts) Giselle has installed a water production well in an unconfined aquifer, She is concerned about the possibility that when the well is in use drawdown will ower the piezometric and that the water will stop flowing. She has asked for your help in the analysis well surface to the bottom of the Currently, the drawdown at observation well A, 120.0 m from the pumped well, s 12.0m. Observation at 80.0 meters is...
A 10 inch diameter well is drilled to the bottom of an unconfined aquifer. The water table is originally 500 ft above the bottom of the aquifer. If 100 gal/min is pumped from the well, the equilibrium depth of the water in the well is 224 ft and the radius of influence is 1000 ft. (1) Determine the transmissivity T of the aquifer and (2). How much drawdown should be expected at a distance of 300 ft from the well?
Problem 24 A well is screened in a completely confined aquifer is to be pumped at a rate of 165,000 ft/d for 30 days. If the aquifer transmissivity is 5320 ft/d and the storativity is 0.0007, what is the drawdown at 50, 150, 250, 500, 1000, 3000, 5000, and 10,000 ft Problem 25 If the aquifer in problem 24 is not completely confined, but overlain by a 8.0 ft leaky confining layer with a vertical hydraulic conductivity of 0.024 ft/d...