This might prove of interest to you guys with ponds. It'd be a great way to check out structure conditions, bottom makeup, etc.

I've been considering buying one of those live video underwater cameras to fish and evalute the pond with. However, the price has proven a bit too much to me. I've got some basic knowledge of electronics and so I did a search on the web for plans on building one of these cameras yourself. There are two websites that sell plans for this project, and claim you can build it for under $100. I'm going to try to figure it out on my own but may opt to buy the $9 plans from one site.

From what I gather thus far, your basic setup would be: A low light level B&W minicam encased in PVC pipe, a pole to mount it on, both a video and power cable running down to it, a B&W portable TV set, and a 9-12vdc battery power source. You can also use LEDs on the camera housing to enhance low light conitions. Beyond that my research has just begun. Any thoughts welcome.