Trenching to disrupt water table / flow - 05/07/09 06:08 PM
Hi all - reporting back on the leaking pond and seeking advice of course!
I have a 1/4 pond with tiers at 3, 7 and 10ft...all tilled & packed with bentonite at this point.
Problem is I still have strong water flow below ground that blows out the bentonite during the rainy season, then leaks out when the water table / flow lowers. Last fall a french drain (drain rock, perf pipe feeding collected water into the pond) was put in to disrupt the flow, (see very artistic rendering) but it was not dug as deep as the pond bottom it is trying to protect. So it’s still blowing out the bottom few feet of the slope and leaking. A little hard to see in the pictures, but the water is flowing directly in from the slope…the slope above is dry. The bare dirt is where the sides sloughed off.
Here’s the dilemma – the original trench was done incorrectly and I want to go back to them with a little more knowledge this time. How do I create a trench that’s deep enough to disrupt the flow and still collect the water? Feed it somehow into the existing trench? The feed is gravity based so if I trench deeper than the 2nd tier of the pond…I need to pipe the feed into the 3rd tier?
Or trench the water around the pond completely and release it below the dam to get rid of the pressure altogether?
From a tactical standpoint what options are there for trenching 10+ ft down, as narrow as possible? Guessing this isn’t equipment I can pickup at Sunset Rentals and do myself.
Any insight is appreciated…
Brad in Oregon -
I have a 1/4 pond with tiers at 3, 7 and 10ft...all tilled & packed with bentonite at this point.
Problem is I still have strong water flow below ground that blows out the bentonite during the rainy season, then leaks out when the water table / flow lowers. Last fall a french drain (drain rock, perf pipe feeding collected water into the pond) was put in to disrupt the flow, (see very artistic rendering) but it was not dug as deep as the pond bottom it is trying to protect. So it’s still blowing out the bottom few feet of the slope and leaking. A little hard to see in the pictures, but the water is flowing directly in from the slope…the slope above is dry. The bare dirt is where the sides sloughed off.
Here’s the dilemma – the original trench was done incorrectly and I want to go back to them with a little more knowledge this time. How do I create a trench that’s deep enough to disrupt the flow and still collect the water? Feed it somehow into the existing trench? The feed is gravity based so if I trench deeper than the 2nd tier of the pond…I need to pipe the feed into the 3rd tier?
Or trench the water around the pond completely and release it below the dam to get rid of the pressure altogether?
From a tactical standpoint what options are there for trenching 10+ ft down, as narrow as possible? Guessing this isn’t equipment I can pickup at Sunset Rentals and do myself.
Any insight is appreciated…
Brad in Oregon -