Possible Underground Leak

[EOIT]

I work at an older power plant with several outdoor water storage tanks on site. Near one of these tanks we have developed a large puddle ~ 8 ft around and 1 ft at its deepest point.

At first we thought there was a leaky valve contributing to the accumulation of water, but after securing the valve, sandbagging the site, and allowing a few sunny days to pass the puddle is not noticably smaller. There are a couple of known pipes running under this area but when it was excavated a few months ago no leaks were found. One concern is that there are 'bubbles' coming up from the dirt which is somewhat perplexing.

Now as the new eng. on the block my boss wants me to solve the problem. So, does anyone have any suggestions on looking for underground leaking. I was thinking about adding a dye to the tank to see if that 'surface' in the puddle, if anyone has any suggestions on what type/brand that would be useful.

Thanks in advance.

 

[unclesyd]

You have several avenues of approach first I would check with the local utility company a talk to someone about their approach.
This is one type service they could use.

http://www.util-locate.com/leaks.htm

There are quite a few ultrasonic systems for detection of leaks in swimming pools and pipes available in most localities .

You might give these people a call and see what available in the Ultrasonic line also they have service companies located around the country.

http://www.uesystems.com

You might also want to do a search on Google “underground leak detection

 

[eyec]

if you have access, you may want to run a crawling video-probe down the line.