What is Water flow: Definition and 162 Discussions

Environmental flows describe the quantity, timing, and quality of water flows required to sustain freshwater and estuarine ecosystems and the human livelihoods and well being that depend on these ecosystems. In the Indian context river flows required for cultural and spiritual needs assumes significance. Through implementation of environmental flows, water managers strive to achieve a flow regime, or pattern, that provides for human uses and maintains the essential processes required to support healthy river ecosystems. Environmental flows do not necessarily require restoring the natural, pristine flow patterns that would occur absent human development, use, and diversion but, instead, are intended to produce a broader set of values and benefits from rivers than from management focused strictly on water supply, energy, recreation, or flood control.
Rivers are parts of integrated systems that include floodplains and riparian corridors. Collectively these systems provide a large suite of benefits. However, the world's rivers are increasingly being altered through the construction of dams, diversions, and levees. More than half of the world's large rivers are dammed, a figure that continues to increase. Almost 1,000 dams are planned or under construction in South America and 50 new dams are planned on China's Yangtze River alone. Dams and other river structures change the downstream flow patterns and consequently affect water quality, temperature, sediment movement and deposition, fish and wildlife, and the livelihoods of people who depend on healthy river ecosystems. Environmental flows seek to maintain these river functions while at the same time providing for traditional offstream benefits.

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  1. S

    Velocity of Fluid flow due to gravity

    I am designing a system for an engineering project at school. It's essentially a clock to be powered by water turning a mechanical system of gears (not generating electricity). Imagine a rectangular basin full of water placed at some height above the ground. There is a hole in the bottom...
  2. danielng245

    Please help calculate flowrate frm blower to push water down

    How to calculate how much flowrate from blower i can push water pool 2,75m*1,8m down by 1,25m in 1 sec? Note : Blower Pressure 0.03 bar - 0.035 bar There is an empty room above the water pool with dimension of 2.75m*1.8m*1.7m This process happen in a closed chamber...
  3. P

    How Does a Rain Catchment System Affect Water Levels in a Tank?

    I am volunteering at an orphanage in Guatemala. There is no well, and the city water is a relatively expensive. I would like to install a rain catchment system on our roof for use in the outhouse bathroom and garden. I've diagrammed it and attached the image. My question is this: Will the...
  4. D

    Please explain curious behavior with my rainwater barrel

    I have a barrel that collects rainwater from the gutters on my house. At the bottom of the barrel is a manual 'faucet' with a round handle for turning the flow on and off. On that spigot, I have installed a "Y" fitting. One side of the "Y" goes to the irrigation hose which I turn on when the...
  5. S

    Water flow rate (or pressure) drop question

    Hi, I'm not sure if I'm posting in the right spot but I'm going to guess this is an easy question for you all. I'm going to give as much detail as I can, maybe too much.. My 2 family house condo has a single 2" or 3" water supply from the street. It is split to supply the first floor and...
  6. N

    Why does water flow faster through a hose if its choked?

    A thought came to me while pouring antifreeze into my car today. As I pour in the anti-freeze it fills to the brim and takes awhile to flow through the cooling-system. However, if I choke the hose a few times it for some reason swallows the antifreeze faster. Is this similar to the bottle-neck...
  7. Corin511

    What is the relationship between water stream diameter and distance from faucet?

    Homework Statement Daphne goes to the kitchen for a glass of water. She turns on the faucet so the stream of water is laminar flow. She notes that the diameter of the water steam decreases with distance below the faucet assuming that the water exits the faucet of diameter D with speeds v0...
  8. R

    Water flow in pipe with two open vertical offshoots

    Homework Statement Water (η = 1.00E-3 Pa·s) is flowing through a horizontal pipe with a volume flow rate of 0.0125 m3/s. As the drawing below shows, there are two vertical tubes that project from the pipe. Assume that H = 0.0458 m and L = 0.738 m. Calculate the radius of the horizontal pipe...
  9. V

    Calculating Change in Flow for P1 & D1

    If I have a flow , Q1 l/sec and a pressure P1 Bar , Pipe Diameter D1 how can I work out the change in flow if either/or both the Pressure or Pipe Diameter change. Assuming laminar flow and pipe material do not change. Thanks
  10. Y

    What is the relationship between flow rate and pressure in pipes?

    [b]1. Good day to all. Would appreciate all your help for my understanding please. I am quite new to this topic of fluid dynamics. a) Say i have a 1200mm pipe which eventually serves a main distribution network. However, I will close the valve to the distribution and allows the water to...
  11. O

    Install Rain Drainage System: 6000 m2 - 9.5 m 6" Pipe Every 10 m

    I have a hanger i need to install rain drainage system, note the rain in the area is medium. Dual areas total of 6000 m2 will collect water. Each area 3000 m2 will have a downward 9.5 meter 6" pipe every 10 meters and goes horizontally 10 meters for the main outlet pipe. both 3000 m2 area...
  12. H

    Calculating Nusselts Number for Water Flow

    hey guys i got a problem.If you are given the bulk temperature of water, flowing at a velocity of 1.5m/s, to be 32 degrees celsius and is flowing through a 2.54cm ID duct which has a wall temperature of 43 degrees celsius. How can you calculate the nusselts number using three different ways?
  13. Q

    How do you calculate total head in ground water flow?

    Its attached below. I don't understand how you work out the total head. Can someone explain how you do it? I'm really struggling. I know how to do the elevation, which is just the height above/below the datum level. And I've checked the solutions as well, it seems like you're supposed to work...
  14. S

    How Does the Decay Constant Influence Water Flow in Exponential Decay Models?

    When modelling exponential decay in class we did a water flow through a burette experiment. We were given the equation V(t)= V0 e^-λt and ln(V0/V)=λt Where lambda is the decay constant, V0 is the initial volume and V is the volume at any time t. What does the decay constant actually tell you in...
  15. J

    Calculating velocity of water flow form tap

    Homework Statement A measuring cylinder collects 475 mL of this water in a minute. At the top the diameter of the stream is 0.700 cm. Homework Equations What is the velocity of the stream 20.0 cm below the top? The Attempt at a Solution im not sure which formula to use? i was...
  16. Z

    Force of a water flow through a U-shaped pipe

    Homework Statement Water flows at a speed of 0.75 m / s through a U-shaped tube whose cross-section is circular with a radius of 10 mm. How large is the force F to be to compensate for water power on the tube? Homework Equations I am not sure. Perhaps; Pressure=Force/Area...
  17. R

    Calculating Water Flow: Time to Fill Canister

    I have been trying to work out a formula to calculate how long it might take to fill a container of a known capacity in various depths of fresh water. The container would have a foot valve for entry and a pipe extending above the surface for air displacement. Tests at 1metre deep have given...
  18. C

    Water flow rate equation. HELP

    Hi, Me and 4 others are stumped on our HNC Electrical Project. We need an equation that calculates from the flow rate of water and diameter of a pipe, what amount of electrical power outage can be gotten by using a simple turbine connected to the pipe. Any sort of help would be greatly...
  19. J

    Is there water flow against gravity?

    Hi all, I have been with this issue for some time and think I reached a conclusion but am not sure and was hoping that you guys could help me out with this. http://spreadzed.com/water_flow/water.png I was considering the scenario where you have a closed tube like the one you see in the...
  20. A

    [Fluid Mechanics] Water Flow in a Hose

    Homework Statement Given: Water flows through a 15.24m long, 1.6cm diameter hose. pressure at the outdoor tap = 275.8kPa volumetric flowrate, Q = 7.5e-4 m^3/s (i.e. 7.5L for 10 seconds) viscosity of water, μ = 0.001 Pa*s density of water, ρ = 1000 kg/m^3 Look for: the roughness of...
  21. B

    Calculating Water Flow into a Pipe

    Hi all, I have a practical problem at work that I need some help with please! In the ground, there is a gas pipe that runs alongside a burst water pipe. There is a hole in the gas pipe of approx 40mm in diameter, and the water is blasting the hole with constant water pressure of 4000...
  22. R

    What is the Optimal Water Flow Rate for Different Pipe Diameters and Pressures?

    what is the water flow rate at an open 1/2" tap through 19mm diameter and 22mm diameter pipes at 4 bar pressure? I currently have 1/2" pipework and the delivery rate is terrible although I am told the incoming supply is from a 22mm pipe with 4 bar pressure. I am thinking of replacing the...
  23. K

    Restrictive piping and water flow

    Hi, new to the forum and I'm looking for some help with water flow problem. I have a geothermal heating system. However, when installed a regular hot water tank was used to act as a buffer/holding tank to heat my floor. My question to anyone that can help is this; The manufacturer recommends...
  24. R

    Water flow calculation through tee pipes

    Hi I need help calculating water flow through a few tee pipes. Water flows to the plant through a 36” diameter pipe @3500m3/h and 220kPa for 9m before teeing out to a 24’’ pipe (1.5m high with butterfly valve). The original 36’’ than immediately encounters a 90 degree bend before it is...
  25. M

    Calculating Water Flow Time in a Tube | Gravity-Powered Flow Question

    Hi all! If I had a tube with diameter x cm, filled with water, how would I calculate the time it takes for a volume V of the water to pass a point in the tube, flowing completely due to gravity. Thanks
  26. T

    Water flow down a porous channel (Navier-Stokes/Fluid dynamics)

    Homework Statement Water flows down a channel whose floor is porous, so that water seeps out of the bottom of the channel at a speed v, where v is constant and much less than the flow speed, U, along the surface of the channel. The seepage rate is slow so that H may be regarded as constant...
  27. 1

    Calculating Drop Size, Number and Time for Water Flow Through Capillary

    Homework Statement Trough a capillary with an inner radius r=1mm water flows in a form of small spherical droplets. What is the radius of the drops, the number of drops in m=10g water and the time needed the water to expire, if the surface tension of the water is =72x10^-3N/m, and the period...
  28. M

    What are some tips for improving accuracy in shallow water flow simulations?

    I'm trying to create a simulation of shallow water flow and I keep getting huge values of variables. Does anyone here have experience with this type of computer simulations?
  29. D

    MHB Watch Amazing Water Flow Visualizations - From brusspup!

    Here is a great video of water flow: http://www.youtube.com/user/brusspup
  30. P

    Solving Water Flow in a Taper Pipe Problem

    Homework Statement Water entering a house flows with a speed of 0.228 m/s through a pipe of 1.08 cm inside radius. What is the speed of the water at a point where the pipe tapers to a radius of 2.39 mm?Homework Equations Continuity equation: A1V1 = A2V2 Bernoulli's Principle: P1 + .5pv1^2 +...
  31. M

    Shallow water flow - equation system unstable

    Hello, everyone. I'm working on simulating shallow water flow. I'm using the MacCormack scheme and fractional predictor-corrector steps. The Dxy factor should make the equation system stable but no matter what numbers I input, the results skyrocket, up to 10^80 and more. Has anyone worked...
  32. B

    Water Flow, Mass Flow through 5 Gallon Jug

    Here is the run down first, I'm trying to find a min mass flow rate for my project which needs to be 1 GPM, and max 4 GPM. Now water is going out of a 5 gallon jug, that has the top cut off, and the water is flowing into a PVC pipe. The area is already set at 1.5 inches, which I know is to...
  33. N

    Maximising water flow into an intake on a race boat

    I've looked at lot of information on the net and have picked up a few things. My query is how to work out the optimum radius and measurements for the lead into an intake on a racing jet boat? We cruedly term it the 'spoon effect' where the water runs along the bottom of the boat and up into...
  34. M

    Range of Water Flow with 2bar and 45° Angle

    hlw, this is Shafieur...i m in a problem to calculate the range of water with pressure 2bar and angle 45 degree. pipe dia is 1.5 inch...
  35. D

    Water flow feed rate for hydroponic grow unit

    how do you calculate the amount of water that can be supplied to pvc pipe with an exact number of holes drilled into it to feed plants water 3/32" diameter hole in 1/2 pvc pipe each pipe has 29 hole 5 pipes approx 88" long connected to a 1" pvc pipe manifold water fed through drilled holes must...
  36. L

    Calculating Heat Capacity & Water Flow to Melt Honey Barrels

    Hi there, I am not an engineer but i do have scientific background. It is just a long time since i did any calculations! I am trying to design myself a new way of melting barrels of honey. I have 200L, 300kg barrels of crystalized honey that I need to melt. One method I envisage is to make an...
  37. W

    Calculate Power from Water flow

    Hi, I am interested in building a water turbine. I am not sure how to calculate the theoretical maximum power that can be derived from a flow. If I assume I have a flow of 5m/s and a channel (or pipe) 1m^2 then I have a volume of 5,000 l/s How do I calculate the energy that this flow...
  38. B

    Steam, preesure and water flow project. I Cant understand the behavior.(+Movie)

    Hello All, I'm working on a project and one of the main parts is this pressure vessel that is sealed air tight that has 2 tubes coming out. One is straight and the other is a U tube. I have a 2.5 KW heater coil in the water to boil the water in order to create steam to raise pressure and move...
  39. E

    What restricts the water flow?

    If I want to measure the flow at the bottom of a rain water pipe, then want to add a nozzle... how can I calculate the flow at the nozzle? will it be the same? I have experimentally measured Q at the big pipe. I want to design a Pelton turbine so I have to know how to calculate the flow...
  40. E

    Question asking me to show that the water flow rate is approximately 26kg\s

    [b]1. A farmer builds a water storage tank 12m above ground. The water is fed via a 200m long, 125mm diameter pipe to a field for irrigation purposes. The pipe has a friction factor of 0.008. Using the K data below, show that the water flow rate (kg/s) in the pipe is approximately 26kg/s...
  41. C

    Water flow speed through a pipe

    Homework Statement Water flows through a 1.3 cm diameter pipe into a 295 L bathtub, which it fills in 5 min. What is the speed of the water in the pipe? Homework Equations V_in=v_L*t*A_L (Equation I got in my class lecture, I think its a variation of bernoulli's.) The Attempt at a...
  42. P

    Calculating Water Flow Duration in Cylinder Reservoir

    Hello. Homework Statement There is a vertical cylinder-shaped reservoir full of water: Height h = 18 meters Radius R = 2 meters If suddenly a hole appeared on the bottom (radius r = 0.25 meters) how long would it take to empty the reservoir? Homework Equations Probably related to...
  43. Overflowing

    Water flow rate through a slot at surface

    I've been searching all over in aquarium related forums for an answer to this questions and haven't been able to find a definitive answer. Background: Many saltwater reef aquariums utilize a filtration system located in a sub-tank (called a sump) beneath or remote of the display tank...
  44. A

    Measuring Water Flow From an Elevated Bottle: Physics in Action!

    If I do an experiment where I want to work out how fast a certain amount of water will empty from an ordinary plastic bottle elevated greater than horizontal, what Physics could I apply if I measure the angle at which it is emptied, the height above the ground and how long it took to empty. I...
  45. P

    Raising a Sunken Vessel: Calculating Air & Water Flow

    This is a real world problem. We have a vessel sunk in about 50' of water and need to raise it. We have devised a way to pump the water out and pump air into replace the water. It is important that we keep the differential pressure very close to Zero and running a "snorkle" tube is not an...
  46. A

    Calculating water flow rate to achieve lower skin temperature

    Hi! I need some help with the following - I have a square oven that has an outer shell of stainless steel (10mm thick) that has a skin temperature of 180degC. Outer shell size of each side is 800mm x 800mm. This has to be water cooled to bring down the skin temperature to 50degC. We need to...
  47. S

    Detecting Water Flow Through Pipe

    I'm looking for a way to detect water flow through a pipe. For example, I want to detect when a toilet flushes or leaks. I'm looking for a way to detect this that doesn't require anything submerged in the tank or inserted into the water line. I really just want to know that water is flowing...
  48. B

    Calculating Change in Temp. with Steam & Cold Water Flow

    Homework Statement Steam is passing a pipe that has cold water flowing through. I need to find the change in temperature from when the water enters the pipe to when it leaves the pipe. Homework Equations First i found the total thermal resistance using...
  49. D

    How Does the Continuity Equation Apply to Changing Water Flow in Pipes?

    Homework Statement http://img41.imageshack.us/i/1721001.jpg/ #18 Homework Equations proportions The Attempt at a Solution i would think water flowing is directly proportional to the diameter so i got V1/D = V2/d V2 = d*V1/D but the answer is E
  50. N

    Calculate Force on Steel Wall from Water Flow

    We have a water pipe which is 750mm diameter assumed running full with a flow rate of 152l/s. When the water exits the pipe there is a steel wall approx 1.2m in front of it and I need to determine the force that the water exerts on the wall? I have claulcated that the water is running at...
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