Suresh,

If the reservoir draws down after events, I would assume that it has some
sort of low flow outlet. So you will need to find out info on that, but you
can assume a small pipe of some sort. It would not have huge effect on
flood routing. As to stage storage, you will need to extrapolate that high
enough to maximum weir flow level. The weir is a type of broad crested weir
for which you can obtain the appropriate rating curves with an internet
search, but given your lack of data, a coefficient of 2.6 should work fine.
Go to HydroCAD.net to get a free demo of nifty software that can then run
the computations for you. I hope this helps.

Bill

contact info:

Integrated Land Management, Inc.
3 Lucas Lane
Malvern, PA 19355
610-644-0606 (o)
610-644-6583 (f)
484-995-6840 (c)
wlucas@...

_____

From: hydrologymodel@...
[mailto:hydrologymodel@...] On Behalf Of sureshbabu
parasuraman
Sent: Saturday, January 13, 2007 2:37 AM
To: hydforum@yahoogroups.com; hydrology forum2;
hydrologymodel@...
Subject: [hydrologymodel] A help on Reservoir routing - Reg.



Hi group members,

I am trying to do reservoir routing. I am having stage-storage table for the
reservoir(upto TWL only), and inflow hydrograph details.
I am not having any data like rating curves for the reservoir or
stage-discharge or storage-discharge relationships or table values.

I know only the starting level of the reservoir before the storm event. I
know weir length over which spill occur after reaching the Top water
level(TWL). Spill over weir occur after reaching TWL. Before that no spill
or no scouring too.
Now I am assuming no scouring even spill starts, As i don't have data on
scouring from the reservoir.


My Queries are,

1. I tried to do the puls method. But i struck up with "how to develop the
curves - 2S/del t + O and 2S/del t - O" which is useful for further steps of
the method. I already mentioned above the availability of data with me. I
find difficult with those above data to develop the above curves.

2. I don't know how to develop relation - 2S/del t + O Vs O with the above
available data. Once I got this, I can do other things easily.

2a. How to get stage-discharge or storage-discharge relationship or table
values with the above data of stage-storage table. Even I don't have
stage-surface area values too.

3. My weir length 18 m. How to select the weir coeff.? type of weir is bell
shape. This is the info i have. Spill over weir is in a box type chamber and
go to a channel and go to a next reservoir. Suggest me a good weir coeff.
for my discharge calc. over the weir. I try to use 3. Is it ok.?
I use Q = CL(H^3/2)

4. suggest me some other good method/easy method for the same above problem
of res.routing. Or send me some good literatures on the same subject.

Every efforts from the group would be appreciated.

Thanks in advance.

With regards
suresh"Defeat the Defeat, Before the Defeat defeats You".P. SURESH BABU
RESEARCH ASSOCIATE INSTITUTE OF REMOTE SENSINGANNA
UNIVERSITY,CHENNAI-600025. PH: 22351723 EXTN: 3121RES:5/157-A, "CP.GEETHA
ILLAM",1st MAIN ROAD, SARASWATHY NAGAR, VALLALAR STREET,OTTERI
EXTENSION,VANDALUR,CHENNAI-48.PH:91-44-22751433