Sunday, August 12, 2012

Our pond

Just about a year ago, Tropical Storm Irene gave us way too much water. Irene’s floods were followed by a dry winter, then an abnormally dry spring and summer. Previous posts have reported on our misadventures with flooding and starting a well replacement. The latest episode in this water feast/famine story is our pond springing a leak.

At first, we thought the drought was drawing the water down. The level drops most every summer, and this dry year we weren’t surprised to see a creeping exposure of shore. But when the drought broke and we got seven inches of rain inside a week -- the water level kept dropping. And dropping, to the point of threatening the fish, frogs, clams and everything that lives there. How the heck do you deal with that?

This pond is no ornamental lily pond. It’s an acre-size ecosystem, built 50 years ago by previous owners. They put a concrete “chimney” in the deep end as an outgate that controls the water level. Our wellspring feeds the pond, and when it’s full the water spills into an opening at the top of the chimney, to flow out into a woody marsh via a pipe from the bottom of the chimney. The water height can be adjusted by adding or removing wooden boards embedded in the chimney’s front face, which originally were sealed with tar. Those boards have been rotting over the years, now causing the leaks.

The whole chimney stands 12-15 feet from its base in the muck to a dock supported on top. Even with the pond half empty, the base was still 6+ feet below the surface. The worst leaks through the boards were way down below the water level.

So hubby put on his engineer hat and fabricated a replacement insert from a plywood-type material called Advantech and encased it in rubber. By devising a way to block the outflow through the pipe at the bottom, he was able to remove the old wood as far down as possible and slide in the new insert without draining the pond.

This worked well but didn’t finish the job: As expected, the new “gate” leaked in spots along the sides, with a larger leak at the bottom. Plugging those required underwater work.

At first he and a friend free-dived with just a mask and sealed most of the edges. But the main leak, down in the muck and rubble, persisted.

Thank goodness for friends who have friends with diving gear! It took three multi-hour sessions involving two men in wetsuits taking turns with scuba tanks and weights, using a ladder, multiple ropes, a can of tar, lots of disposable gloves, various scrapers, a garden trowel, and long rubber strips to fully seal the edges and that bottom section. Yours truly manned the “barge” (a 16-foot Grumman aluminum canoe) used as a support platform for the tools and supplies.

The men worked blind in silt that stirred the minute they entered the water. The fish watched, not sure if we were friend or foe, but unknowingly grateful we were saving their home.

We finished the job and the air in the scuba tanks at the same time. A trickle leak remains, which is disappointing but way better than the torrent we started with. Within a few hours it was clear that the water level had stopped dropping -- indeed, is starting back up! Now it’s a waiting game, to see if the trickle will hold or get worse as the rains return. Hubby knows he will be back down there to fully seal that trickle, but when is the question

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