This is a really great review for my groundwater hydrology midterm this Friday. Thank you so much Dr. Wait! You are awesome. Gonna use your videos to study for my FE exam too! You rock!
Thank you. plz help us with this 1. Suppose there are two canals at different levels, separated by a strip of land 1000m wide of permeability K=12m/day. If one canal is 2m higher than the other and the depth of the aquifer is 20m below the lower canal to an impermeable base, find the inflow into or abstraction from each canal per unit length. Take annual rainfall as 1.20m per annum and assume 60% infiltration. 2. A fully developed well, with an outside diameter of 0.5m discharges a constant flow of 0.08m3/s from an aquifer whose coefficient of transmissibility is 25 x 10-3m2/s. The aquifer is in contact with a lake 2km away and has no other source of supply. Estimate the drawdown at the well face. Assume R0 =2L where L is the distance of well from lake. 3. A circular island 500 m radius has an effective infiltration N of 4 mm/day. A central well is pumped to deliver a constant Qo of 25 m3/h from an aquifer with dimensions and properties as shown in diagram. Whrat is the drawdown at the well and at the water divide? 4. Water flows through a sand aquifer with a piezometric head gradient of 0.01. a) If the hydraulic conductivity and the effective porosity of the aquifer are 2 m/d and 0.3 respectively, esti mate the specific velocity and seepage velocity in the aquifer. B) Estimate the volumetric flowrate of the groundwater if the aquifer is 15 m deep and 1 km wide and c) how long does it take the groundwater to move 100 m
Dear Dr. Isaac, Thanks for your lectures. One of the projects where the permeability is needed for the top 5 meters. The well is a semi penetrating unconfined aquifer, but we reach a depth of 30 m and no aquiclude has been encountered. What is the thickness of the aquifier (H) that should be used in the equation in this case? In addition, I don't understand how the thickness of the unconfined aquifier can affect the flow rate into the semi penetrating well. Assuming the well is 5 meters deep, does it make any difference in the flow into the well if the aquiclude is 10 meters or 100 meters deep
Good day! Tell me please, is there any information on the distribution of the depression cone in the confined aquifer? For some reason, they always depict a funnel passing through a waterproof layer. How can it spread evenly through the clay layer? It seems to me that the depression funnel in the confined horizon should be enclosed between the impermeable layers, or am I wrong? Thanks!
For a confined aquifer the depression cone that is being illustrated in the figure is of the pheratic surface (piezometric surface). It isn't the actual location of the water, but rather where the water would rise up to given its pressure within the confining layer. The actual water surface itself will be limited to the bottom of the confining layer (i.e., at the top of the confined aquifer section). If you drill an observation well into the confining layer then the water surface will rise in that observation well up to the location of the pheratic surface. I hope I understood your question, and that the reply is useful.
That is great. For unconfined example for B part of the question, you used h2=23.5 what if we get the h2=23 , will it be still acceptable? Appreciate it
@@davedimond7405 at second part (part B) is asking for draw down at r=5m. In this case you have to accept the h2 from part A, and solve for h1 then you able to find the drawn down at r=5m. As Isaac is getting this h2=23.5 so i am sking can we get this h2=23 as this is aslo a point at r=50m as the 23.5 is a point at r=100 m, appreciate it
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This is the best lecture on aquifers that you can find for the FE exam. I can't believe it's free.
Wow -- thanks.. very kind and much appreciated. Good luck on the FE!
@@IsaacWait thank you Sir
Wow great video I’m a masters student at Texas State University studying groundwater and this video really helped me a lot on my research proposal.
Great! Thank you.
the best of the best lecture of hydraulic on internet, the last 39min saved me 39hrs, thank you Isaac Wait, helped me a lot,
Thank you Yusuf - I appreciate that nice comment. Good luck and best wishes!
This is a really great review for my groundwater hydrology midterm this Friday. Thank you so much Dr. Wait! You are awesome. Gonna use your videos to study for my FE exam too! You rock!
Thanks Connor -- good luck on your midterm and on the FE!
Your videos are the best resource for studying for the FE! You are so awesome for sharing your knowledge! Thank you!
Thank you - really appreciate your kind comment. Good luck on the FE exam!!
Thank you. plz help us with this
1. Suppose there are two canals at different levels, separated by a strip of land 1000m wide of permeability K=12m/day. If one canal is 2m higher than the other and the depth of the aquifer is 20m below the lower canal to an impermeable base, find the inflow into or
abstraction from each canal per unit length. Take annual rainfall as 1.20m per annum and assume 60% infiltration.
2. A fully developed well, with an outside diameter of 0.5m discharges a constant flow of 0.08m3/s from an aquifer whose coefficient of transmissibility is 25 x 10-3m2/s. The aquifer is in contact with a lake 2km away and has no other source of supply. Estimate the drawdown at the well face. Assume R0 =2L where L is the distance of well from lake.
3. A circular island 500 m radius has an effective infiltration N of 4 mm/day. A central well is pumped to deliver a constant Qo of 25 m3/h from an aquifer with dimensions and properties as shown in diagram. Whrat is the drawdown at the well and at the water divide?
4. Water flows through a sand aquifer with a piezometric head gradient of 0.01.
a) If the hydraulic conductivity and the effective porosity of the aquifer are 2 m/d and 0.3 respectively, esti mate the specific velocity and seepage velocity in the aquifer.
B) Estimate the volumetric flowrate of the groundwater if the aquifer is 15 m deep and 1 km wide and
c) how long does it take the groundwater to move 100 m
Dear Dr. Isaac,
Thanks for your lectures. One of the projects where the permeability is needed for the top 5 meters. The well is a semi penetrating unconfined aquifer, but we reach a depth of 30 m and no aquiclude has been encountered. What is the thickness of the aquifier (H) that should be used in the equation in this case?
In addition, I don't understand how the thickness of the unconfined aquifier can affect the flow rate into the semi penetrating well. Assuming the well is 5 meters deep, does it make any difference in the flow into the well if the aquiclude is 10 meters or 100 meters deep
This lecture saved me.Thanks.
Glad it helped!
Thank you sir! I'm gonna use the same problem to my report on our Hydrology Subject. Thank you.
Thanks for your uploading, I am quite confindent to pass my groundwater management exam.
Sir, can you help me get the soft copy of this book; Driscoll, F. G. (1986). Groundwater and Wells (2nd edition).
Good day! Tell me please, is there any information on the distribution of the depression cone in the confined aquifer? For some reason, they always depict a funnel passing through a waterproof layer. How can it spread evenly through the clay layer? It seems to me that the depression funnel in the confined horizon should be enclosed between the impermeable layers, or am I wrong? Thanks!
For a confined aquifer the depression cone that is being illustrated in the figure is of the pheratic surface (piezometric surface). It isn't the actual location of the water, but rather where the water would rise up to given its pressure within the confining layer. The actual water surface itself will be limited to the bottom of the confining layer (i.e., at the top of the confined aquifer section). If you drill an observation well into the confining layer then the water surface will rise in that observation well up to the location of the pheratic surface. I hope I understood your question, and that the reply is useful.
How much competition is there in civil stream?
Very good video!
SIR, I HAVE ONE DOUBT - For the Dam discharge rate which aquifer will have a maximum radius of influence
That is great. For unconfined example for B part of the question, you used h2=23.5 what if we get the h2=23 , will it be still acceptable? Appreciate it
h2 is 24m (the saturated surface level) minus 0.5m (the draw down from the well 100m away) = 23.5
@@davedimond7405 at second part (part B) is asking for draw down at r=5m. In this case you have to accept the h2 from part A, and solve for h1 then you able to find the drawn down at r=5m. As Isaac is getting this h2=23.5 so i am sking can we get this h2=23 as this is aslo a point at r=50m as the 23.5 is a point at r=100 m, appreciate it
Dude this is awesome. Thanks for always having great content.
Very helpful
Thnk u
Thanks Mohammad - glad it was useful to you. Best regards from West Virginia.
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