Asbury Manor-CS090112 (2)
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Ken Griffin - Re: Fwd: Fw: Large volume of water in drainage - Asbury Manor
From:Ken Griffin
To:Clay Phillips
Date:1/12/2009 1:16 PM
Subject:Re: Fwd: Fw: Large volume of water in drainage - Asbury Manor
CC:Glenn Hollowell
Clay
Glenn's memo is long, but the real information is in the last paragraph. This all revolves around
chlorine residuals in the water. And, it seems like the approach we took 49 days ago is actually saving
water. Assuming the lessor of the options in Glenn's response, we probably used 1/2 the water we
would use flushing hydrants. (49 days = 7 weeks / 100,000 gallons per week at various locations =
700,000 gallons of water / our method used 372,000 gallons.) The valve will be closed today.
ken g
>>> Glenn Hollowell 1/12/2009 12:47 PM >>>
Ken,
This "blowoff" was installed by Utility Ops personnel in order to bring up the chlorine residual in this
area of town. It was turned on the Monday before Thanksgiving. We have been struggling with
chlorine residuals in this part of town and other areas. They have been monitoring this area on a weekly
basis. Based upon the discussions that I had with Utility Ops. employees this morning, we are finally
starting to see a good, consistent chlorine residual in this area. As you are aware, we are required to
keep at least a 0.5 ppm chlorine residual in the water system at all times. This area has been giving us
residual problems since September. For the last week or so, the residual in this area has been just above
a 1.0 ppm. The maximum residual that we can have in the system is a 4.0 ppm. We feel confident that
the residual should remain good the rest of the year. I have instructed Ernest to go ahead and remove
this blowoff for the remainder of the season. He stated that he was going to continue to monitor the
area. Now that the residual in the area seems to have stabilized above a 1.0 ppm, any additional
flushing required can probably be handled on an "as needed" basis utilizing fire hydrants.
As I stated earlier, we have been struggling with chlorine residuals in various parts of town since
September. This year, we have had to flush quite a bit more than we normally would. This has been
one of those "bad years" for residual problems. It seemed like it took the water source a long time to
cool off this year. Cold water temperatures will hold a chlorine residual much longer than warmer
temperatures. With the limited number of personnel we currently have, this blowoff was installed in
this manner so that we would not have to have Utility Ops employees flushing fire hydrants most
everyday in this area. Using this type of setup enables us to leave the blowoff unmanned and still be
able to flush the area. By installing a meter on the blowoff, we are able to accurately record how much
water was flushed for our monthly reports.
During November, we flushed 8.3 MG of water in order to keep our chlorine residual legal. During
November of 2007, we only had to flush 2.4 MG. This past October, we flushed 14.1 MG for residual
purposes; but, only 4.9 MG during October of 2007. The meter that we installed for this blowoff only
has 372,000 gallons registered on it at this time. That equates to about 7600 gallons per day that was
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flushed down the channel. The meter was running for 49 days. Normally we use fire hydrants to flush
the water system. We set the fire hydrant to put out approximately 1500 gallons per minute when we
flush. The water running down the channel per day equates to about 5 minutes worth of flushing from a
fire hydrant. On average, fire hydrants are flushed for 15 to 20 minutes a time. This is somewhere
between 23,000 to 30,000 gallons at every flush. Before this blowoff was installed, we were having to
flush this area 2 or 3 times per week at multiple locations. We were probably flushing at least 100,000
gallons per day or 200,000 to 300,000 gallons per week just in this part of town. Since the blow off was
installed, we have not had to flush through a hydrant in this area. I know it sounds crazy, but we have
actually been saving water by using this method of flushing. This method of flushing has the added
benefit of flushing for 24/7 instead of a fifteen or twenty minute period twice a week. Based upon the
residual numbers that we have been getting, we will probably only have to flush this area once per
month using a hydrant. This should last until the water starts to warm up again this Spring. If we
continue to use this method of flushing, we will try to be more discreet with where it is installed in the
future. I believe Mr. Kingsbury may have misread the meter when he made his observation. I believe
the meter was putting out 5.5 gpm instead of 55 gpm.
I hope this helps clear up the confusion over this matter. Let me know if you need any further
information.
Thanks,
Glenn D. Hollowell, P.E.
Assistant Director of Public Works
972-462-5150
ghollow@ci.coppell.tx.us
>>> Ken Griffin 1/12/2009 8:35 AM >>>
>>> Clay Phillips 1/11/2009 3:47 PM >>>
Ken,
Any word yet on what this might be....see below. Thanks.
Clay
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