The weather had been hanging right above freezing for several days and I wasn't sure just how much thawing had been going on in the penstock, other than it wasn't happening fast enough for my liking. Plus there was the lower several 100 meters of steel line into the pelton wheel, it was laying in a shallow ditch covered in leaves and a foot of snow. The snow had been shoveled off most of the penstock a few days previous and walked the line from the bottom to see how it fared. Suddenly, right there at the big stacked rocks, I see a small creek running alongside the penstock that was not there before.
Well holy smokes if the penstock isn't split open and gushing water out the wound.
I climbed the goat trail up the mountain to the intake pond to turn off the water and had a better study of the damage when I got back down.
It has blown the welded seam of the high pressure pipe enough to stick your hand in for a length of five paces. There can be only one reasonable explanation. The ice in the upper black PVC line thawed first, enough to let the ice column start racing downhill. The inside of that pipe would be pretty slippery and any ice in the line could reach a great speed on the near vertical slope. I reckon the the lower steel section was still froze solid. There must have been a pocket of air and some water in between and the column came down and compressed it enough to blow a thick wall high pressure penstock. It must have been a pretty impressive event, as there is evidence of the explosion blown for 6 meters from the split seam.
It is a wonder I didn't hear it.
This was a pretty major problem, more so than anything I've run across before, and one that would be guarantied to be costly, and time consuming to repair.
I retreated to the lodge, lit a candle, put some wood in the stove and cooked a wiener on a stick through the door while I pondered how I was going to get myself out of this most recent jackpot.
The next day at first light I beat a trail up to the site with the Honda and hauled up some chain and a 20 ton jack. With the jack between the chain and the steel pipeline I could press the seam edges back together enough for tacking with a welder.
A local Stevie suggested chains all around. I admit to a bit of an aversion to tire chains and that option never crossed my mind. Anyways we go down the road to the village of Skatin' and bum some chains. Equipped all around the little pickup bounced and clawed its way up the trail towards the base of the falls like a champ and delivered the welding machine to the injured penstock.
I slugged my way up that steep rocky mountainside once more to turn on the water. Arriving back down an hour later, I discover a regular sprinkler going on at the weld. Once the pipe filled with water and reached its operating pressure of 1378 KP (200 psi) it found pin holes in my welding job and was spraying a fine mist from several spots. Well OK I thought that might happen, I marked them with a soapstone and trudged back up the mountain to turn off the water. Arriving back down sweating an hour later I fired up the welder and re-welded the marked areas. Satisfied I took a deep breath and started up the goat trail again to turn on the water. Arriving back down again, I see there is still some pin holes making a high pressure fine mist.
Good lord, I marked them again and headed up the mountain once more to turn off the water and welded over them when I got back down. Whew, glad that's done and headed up to turn on the water. So I drag my self down the mountain aching in spots I didn't know I had, to be greeted by several spots spraying out of the weld again. Well for crying out loud. I decided after three round trips I didn't have another hillside in me and figured I would come back next day to finish up. I was able to start the pelton wheel generating and spent the first night with lights and baseboard heaters in two weeks.
An hour and a half later I was writing a post on my site here.
Early the next morning I turned the system off and bounced and clawed my way back up to the site. I again used a soapstone to freshly mark the offending mist makers. I took another deep breath and started up the mountain to turn off the water flow. Once up there it takes only a minute to drop the flat gate in the intake and cut off the flow of water from the pond. Then you just turn around and start down. It is just as hard on you going down it seems and your knees protest the entire way. I reached the lower section where the pickup was and started up the welder to grind the trouble spots down a bit and then welded over them. I climbed back up the trail once more to turn the water back on. Before I even reach the truck I can see from up the hill there is water sprays coming out. In fact it seemed there was more than the last time. So right back up that torturous goat trail the goats avoid to the intake again to turn off the water, only to turn around and come back down and re-weld it all and go back up to turn on the water only to find it still spraying in a couple spots. I looked at the fine mist. I looked up in the clouds towards the intake. I looked at the fine mist again. I looked up in the clouds towards the intake.
I decided it might be kind of nice to have a nice cool fine mist of water to run back and forth naked in on those really hot summer days. Actually, I plan to go up and have another go at it when I have more time and possible to get up to the intake with the Honda, and avoid having to climb that friggin mountainside.
I had other things to move on to.
Once I opened the water pressure up to the pelton wheel the lights all came on and water to the cabin was re-established and by the time I got back over here the puddles forming from underneath let me know there was plenty of fittings that froze and split. I had drained it all I thought but some pipes were probably frozen by the time I opened the drain. There were 8 repairs needed, including the inch and a half gate valve on the main line to the cabin. I keep spare fittings and valves around so it was not too big a deal.
When I discovered the split open penstock , there was no way I thought it would be up and running running in 3 days.
The hot tub is still down, something got froze there and leaks so I'm going to have to round up some help to get it out so I can work on it.
This will be a winter I will not soon forget.
I got an early start to go in and return the welder to its owner.