4. A single well pumps water from a horizontally infinite confined aquifer at a rate of 6 m³/day beginning at time t = 0. The aquifer has a transmissivity (T) of 50 m²/day and a storativity S of 0.0001. Use the Theis solution (eqs. 9.4.5-7) and Table 9.1 in the Margulis online textbook to calculate the drawdown in a monitoring well located 44 m from the pumping well after 10 days and after 90 days.

4. A single well pumps water from a horizontally infinite confined aquifer at a rate of 6 m³/day beginning at time t = 0. The aquifer has a transmissivity (T) of 50 m²/day and a storativity S of 0.0001. Use the Theis solution (eqs. 9.4.5-7) and Table 9.1 in the Margulis online textbook to calculate the drawdown in a monitoring well located 44 m from the pumping well after 10 days and after 90 days.

Structural Analysis

6th Edition

ISBN:9781337630931

Author:KASSIMALI, Aslam.

Publisher:KASSIMALI, Aslam.

Chapter2: Loads On Structures

Section: Chapter Questions

Problem 1P

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A well is constructed to pump water from a confined aquifer. Two observation wells, MW1 and MW2, are constructed at distances of 10 m and 100 m, respectively. Water is pumped from the pumping well at a rate of 0.8 m³/min. At steady state, drawdown is observed as 5 m in MW2 and 19 m in MW1. Note that drawdown is greater for well MW1 located closest to the pumping well. Determine the Transmissivity (cm²/s) if the aquifer is 40 m thick. (Please enter your answers with 2 decimals)
A well with a diameter of 1 (m) pumps at a steady rate of 500 (m3/day) from a confined aquifer. An observation well A is located 100 (m) away from the pumping well and has a hydraulic head of 200 (m). What is transmissivity(T = K*b)?
A pumping test in an aquifer has yielded the following data: A pumping well with a diameter of 15 cm pumps at a rate of 12 m³/day, and draws the aquifer down by 3.6 m. Drawdown at a monitoring well 20 m away is 1.1 m. a) Calculate the Transmissivity of the aquifer. Assume this number is representative of the entire aquifer. b) Determine saturated hydraulic conductivity, and identify a soil type from table 7.2 in the Margulis book. The aquifer thickness is 20 m. ●
An unconfined aquifer is 10 m thick and is being pumped so that one observation well placed at a distance 76 m shows a drawdown of 0.5 m. On the opposite side of the extraction well is another observation well 100 m from the extraction well, shows a drawdown of 0.3 m. Assume the coefficient of permeability of 50 m/day. a.) What is the discharge f the extraction well? b.) Suppose the well at 100 m from the extraction well is now pumped. Show with a sketch what this will do to the drawdown. c.) Suppose the aquifer sits on an aquaclude that has a slope of 1/100. Show with a sketch what this will do to the drawdown.
Q3. A 200 mm diameter well which fully penetrating a confined aquifer of thickness 25 m is pumped at a constant rate of 2000 m3/day. The steady state drawdown in the well is 8 m and the drawdown in a piezometer 100 m from the well is 1.4 m.(a) Ignoring well losses, calculate the transmissivity of the aquifer, the hydraulic conductivity of the aquifer material and the radius of influence of the well.(b) Repeat the calculation for an unconfined aquifer with saturated thickness 25 m
9) A well is located in a confined aquifer near the intersection of a constant head and impervious boundary. a) Estimate the steady state drawdown in the well for Q=2 ft³ s, rw = 1 ft, distance from the well to stream= 300ft and distance from well to impervious boundary= 150 ft. T = 0.14ft²/s b) Estimate the steady state drawdown at point P located midway between the well and the steam. The angle between the stream and the impervious boundary is 90°
A confined aquifer of 15 m constant thickness is sandwiched between two aquicludes as shown in the figure (not drawn to scale) 55.2 m BT Peizometer P Reference Datum Aquiclude Piezometric Surface Aquiclude Peizometer Q L = 2500 m 34.1 m ונטוב SOM The heads indicated by two piezometers P and Q are 55.2 m and 34.1 m, respectively. The aquifer has a hydrau- lic conductivity of 80 m/day and its effective porosity is 0.25. If the distance between the piezometers is 2500 m, the time taken by the water to travel through the aquifer from piezometer location P to Q (in days, round off to 1 decimal place) is
9.An unconfined aquifer with K-30 m/day is bounded by a stream on one side as shown in Figure 2, At a distance of 80 m from the stream, a well of 0.4 m diameter is pumped at rate of 3000 m³/day. What is the drawdown in the well? Q=3000 m³/day 20 m m 801 Figure 2 C C d=0.4 m K=30 m/day Impermeable Layer m³ / day
The time – drawdown data for a confined aquifer is given below for a discharge of 1500 gpm. The distance of the observation well is 300 ft. here, T=52849.388 ft^2/day and S=0.000568 A.Show that the basic criteria for using Cooper-Jacob approximation is satisfied. B.For the computed T and S values, what is the limiting value of time ‘t’ that satisfies the basic criteria of well function parameter ‘u’?
2. (a) A well in an aquifer is pumped over a long period at a rate of 0.05 m3 /s under approximate steady-state conditions. The steady-state drawdowns, from the water table level, at two observation wells at 25 m and 50 m from the abstraction well were observed to be 15.3m and 9.5m, respectively. If the saturated thickness of the aquifer prior to pumping is 80 m, determine the hydraulic conductivity of the aquifer material. (b) Will the actual drawdown in the pumping well be more than the theoretical drawdown? If yes, why and what measures can you recommend for reducing the drawdown in the pumping well?
If the distance and observed potentiometric surface between two adjacent wells are 1000 m and 3 m, respectively. Find an estimate of the time it takes for a molecule of water to move from one well to the other. Assume of 3.5 m/day and effective porosity of 0.35.
A well in an unconfined aquifer is pumped at the rate of 50 L/s ( 800 gal/min.). The thickness of the aquifer is 30 m. and the elevation of the phreatic surface is 25 m. above the underlying aquiclude at an observation of well 20 m away from the well and 34.6 m above at a well 50 m. away. What is the value of K for this aquifer?