Search results for query: *

psmart, thanks for your feedback but if a local rainfall distribution and custom unit hydrograph are used then what's left of the NRCS method ? I have come across a method called alternating block model which might be useful cause i only have IDF curves, can you point me to text books or web...

Hi, I've never worked in hydrology before and just got an opportunity to work on storm water management system project which will include lots of modelling of routing structures, pipes, channel and possibly reservoirs. I’m doing text books readings and have the following questions for a start...

People, Just wondering , has anyone faced anything strange when working with watercad 6.0 or 6.5 system curves , I got the system curve off watercad and drew it against the same pump curve I've inserted into watercad but the crossing point doesn't give the flow that watercad is giving in the...

All, thanks for all the replies, I thought the title of my question was enough to avoid the confusion. jimcasey, if it externally sensed, you said it will work normally , but for which direction ? both direction of flow ? if the valve is internally sensed and it work like you said then why...

All, I've come across an existing PRV valve installed in a way that it is subject to flow in the reverse direction it should normally works in. I know that some PRVs come with a check valve feature so this shouldn't be a problem for them, my question is what happen to the valve if this feature...

All, these are existing pumps, throttling will be for a short period of time. its pumping 300 l/s against 72m head through 600mm GRP pipeline. control valve and VSD are more expensive in capital cost and will take long time to be done. the client wants something low in capital (high in O&M is...

Hi, I can easily draw a system curve for a single pipeline, but how do you do that when you have a network of pipes? I know that each route will have a different system curve, should I just draw the system curve for the route that will give me the lowest pressure and match this with a pump...

Hi all, I have a situation where the pumps are pumping outside of its curve, max flow. the client has no problem with throttling the outlet to move the duty point back on the pump curve, he knows all about the energy losses and don't care. I was concerned about the pressure drop required to...

Hi, I ran a Google search looking for this but nothing came up so far. Does anyone have a technical paper or a guide in estimating pipe roughness over time (more than 10 years) for GRP pipes ? I would expect the roughness to be directly related to the type of fluid transferred, velocity ...

All, What are the main benefits of modeling a sewer system with a backwater analysis? I know that this way you can locate hydraulic jump locations and exact water depths in each pipe segment but are there any other advantages? I can see the benefit of locating a hydraulic jump but isn’t an...

All, How would you size the house connection for a high rise building, I know that no body put these in water distribution models so how do you size it ? I thought about assuming a fixed velocity "say 0.5m/s" and use the peak demand for each building to come up with a reasonable size...

Thanks a lot everybody. That was very helpful. I’m new in the water distribution network design. There is a senior guy in the office who is convinced that controlling the pumps near consumers “2km away” would give the best indication of system pressure. I checked the model for severe changes...

cdafd, I wish they do! regards.

gouveia, you are right, this a development in a city. but not in the states. I have never heard of IFC before. the city I'm working in is an old third world country city that has nothing like the develpment we are working on. the local authorities there don't have a clue on what standards or...

All, Hi, I was looking into using an altitude valves for a buried "underground tank". how will this valve sense the high water level in the tank if it will be positioned above the high water level. Would a simple solution of lowering the altitude valve to below the high water level solve this...

*Pump2005, you said system pressure : how do you measure that and where do you measure it and how do you send the signal to your pumps ? *thewellguy, "I would use vfd's to control the pumps from a transducer located in the pumphouse" Can you please explain more, do mean pressure transducer...

RGasEng, Thanks for your help, I was mainly looking to get standard to estimate the required flow at fire hydrants installed on the potable water network in a city. I have not read through yet but I think the NFPA codes I mentioned have that in them but they are not intended for cities.I ran a...

Hi All, I was looking for the NFPA code on Standard on Water Supplies for URBAN "cities" areas Fire Fighting but couldn't find one. there is NFPA 1142 which is for suburban and rural areas and there is NFPA 1141 which is Standard for Fire Protection in Planned Building Groups but when I read...

unclesyd, Thanks again, to clarify 1- I'm not really concerned about the system after the tank; I'm looking to control the system feeding the tank only. 2-I have not said "altitude switch" maybe this is the same thing as "altitude valve" which I did mention, but I really don't know whether...

Hi all, I'm currently working in a closed system of potable water distribution system, pumping directly to consumers, there are no storage tanks that I can use to shut off the pumps when it gets filled, so what is the most common way of controlling the pumps in this case ? 1- Pressure sensors...