Aquatic Gardens Ponds, Streams, Waterfalls & Fountains: Volume 1. Design & Construction Volume 2. Maintenance, Stocking, Examples V. 1 Print and eBook on Amazon V. 2 Print and eBook on Amazon   by Robert (Bob) Fenner

Pond Liners   10/21/11
Hi,
At present we have a hole in the ground that is approx 55' in diameter and 6' deep. This was excavated by previous owners. I was thinking that I would like to reduce this to 45' in diameter and about 4' at its deepest.
<Mmm, okay... there are ways to backfill, put up walls...>
(Q1). The soil is heavy clay, should I puddle the soil to prevent water seepage or put a liner in or something else?
<Need to have soils tests done to determine. See the "yellow pages"... Some clays work, some can be augmented...>
(Q2). The water table is fairly high here, therefore should I have drainage put in before we start or is that dependent on the type of liner?
<Good question and yes! W/ any (sizable) volume basin, provision should be made for drainage
If the answer to Q1 is puddle the clay can I put something on top of the clay to prevent unwanted weeds?
<Not really. I've seen (over the decades) various mats, weaves....
materials advanced that assert they'll do this. Never work. Best to keep a close eye on the system, physically remove, use bio-control/s or chemically treat if/when you spot "weeds">
In the summer this hole can dry out allowing lots of vegetation to grow.
if the answer to Q2 is a liner, will drainage prevent water seeping under the liner and thus cause it to lift or can I put pea gravel on the liner to prevent it lifting?
<I wouldn't use gravel... a mess, and will destroy the liner to remove>
Many thanks for your help
Jim
<Welcome. Bob Fenner>

Natural pond to waterfall transition construction? 6/17/09
Hello,
I am planning to construct a waterfall from a manmade (branch fed) non-liner pond over an earthen dam and would appreciate how to make the transition from the pond into the waterfall trough. Currently the pond which is approximately 25' long 15' wide and 6' deep at the center, drains through an 8" PVC pipe installed vertically and elbows under the dam to drain into the existing stream bed.
<A good idea to "sleeve" this overflow... to direct water and solids from the bottom of the water column... cut some notches in the larger diameter pipe's bottom... and slip it over the 8", a couple inches higher in height...>
This keeps the water level from overflowing the earthen dam.
<Good>
I intend on constructing a concrete trough, roughly 3' wide and 12" deep over the top of the dam and using a liner underneath and down the waterfall path. The top of the dam is about 6' across before the fall starts of about 20 feet in length at an angle of approximately 45 degrees back into the existing small stream bed. My concern is where the pond meets the trough.
I was told not to extend the waterfall liner into the pond since water will be able to leak under the liner,
<This is so... capillation will/would work here to weaken the earthen dam...>
so I plan to start the liner about 3' back (under the concrete) from where the pond meets the mouth of the trough.
I intend on using plastic cement with wire grid or rebar to cover the trough and waterfall.
<With the water level lowered...>
I am unsure on how to construct the "mouth" of the trough.
<And I am hesitant to encourage your doing so w/o more substantive information>
Any suggestions on how to form the mouth of the trough to prevent leakage or erosion under the cement would be greatly appreciated.
<Well...>
Also I will extend the 8" PVC pipe to just above the water level to act as an overflow during heavy rains since this small creek can turn into a small torrent at times.
<A very good idea... I would have two such egresses, both sleeved>
Appreciate your suggestions.
Alan
<Do understand my alacrity here... and direction in encouraging you to have a soils engineering firm up to review your situation in detail. At the worst, what might be the consequence of the earthen dam giving way all at once? Are there weir dams distal? I would be very hesitant to modify the existing berm myself. Bob Fenner> 

Re-install Large Pond In Clay Soil, Pond Near House Re Installed After Collapse  11/15/07 Dear Crew. Put in 4' deep x 8' wide x 33' long Koi pond about 3 years ago. < Wow, that is a really big pond.> Concrete block mortared together for side walls. In bottom we put 2" sand, then underlayment of carpet backing, then EDPM vinyl liner. We included a large biological waterfall (using a 150 gallon rubber water tank filled with filtering materials). The pond lays 4' from the house and stretches along the length of the front sideway between the house and the sidewalk. The soil here is clay and develops very deep wide crevices during the heat of summer. < A typical expansive clay.> About a year and half ago we drained the pond because our house foundation fell. We had a contractor put concrete piers along the perimeter to re-level. We don't know if the pond had anything to do with it, but don't believe it did, although we continually had quite a bit of water loss that we feel was the waterfall. <The house fell for a reason. The piers transfer the load of the foundation from your house down past any influence from the pond. Hopefully the soil there is much stiffer.> In the meantime our two gorgeous Koi have been living in 150 gallon tank, and we want to go ahead and re-install the pond, but want to take extra precautions against any possible leaks as it is so close to the house. Do we need to do anything extra than your suggestions of liner, then concrete, etc.? My plan is to keep the old liner in (although not trustworthy as re-modeling materials during structure tear down were thrown into it), go ahead and put a new liner in and proceed from there. Also, we have decided to bring the pond up to a 2' depth and need advice as to what material would be best to do this......just dirt or what about pea gravel......or sand?? This would go over the old liner, and then we would continue per your site instructions..... Sorry to be so lengthy but would appreciate any thoughts before we do this. Thanks Darla McLeroy <Any material that you use to bring up the pond bottom needs to be compacted to prevent differential settlement. Use whatever is the most cost effective and densify the material in 8" lifts using a mechanical hand whacker up to the grade you desire. The last lift or top material needs to be a material that is recommended by the manufacturer of the liner. If you use a pea gravel as fill then a sand used on top will just fall through. If you use soil it needs to be free of any sharp objects like stick and stones. Pea gravel is almost self compacting but holds lots of water between the pore spaces.-Chuck>

Clay pond problems  7/11/06 Hello, I live in a remote area of British Columbia. We don't have a aquaculture center within 300 km.s. Four years ago, while digging the foundation for our new home, my husband decided to have the excavator operator dig a pond for me. <Good timing> The plan was to pack the clay banks with the excavator to waterproof it. <Mmm... doesn't often work> Much to their surprise five feet down they came across a spring that rapidly started filling the pond to a depth of four feet. Great! Except that the banks are about ten feet higher than the water surface and the grade is very steep. Too steep and mushy for a sheepsfoot roller. <Dangerous...> The pond is about one eighth of an acre and in a very wooded area, now inaccessible to an excavator. The soil on and around the banks in a dense clay/silt composition, mosses, wildflowers and grasses have started to grow around the pond. The pond is located in a natural swale and fills to the rim in the spring. Every year the level does seem to be staying higher. <Typical... consolidation of "over-burden"... do make preparation for when it will overflow...>    I would like to keep the water level up, create a natural looking bog for filtration and stream for aeration and prevent silty run off from getting into the pond. <Okay> I've heard of packing horse manure into it, which I think would put too many nutrients into the pond, <Yes... a mess that would take years to remedy. Don't do this> Bentonite clay which isn't cost effective <... is amongst the cheapest routes> and due to the extreme nature of our climate (it's either very dry or very wet) isn't applicable or scarifying the soil and foot packing it. Please can you offer some suggestions? Its a huge project that I would like to do properly. Thank you for your time- I've been scratching my head over it for a while- Nancy Jensen <A tough query to respond to... there's no telling what the disposition of the "eternal spring" under this basin will do... If you were really desirous of making this basin permanent, I would drain it, fit a liner... and a concrete berm/safety bench around the perimeter... As it is, w/o putting a few tens of thousands of dollars into this project, what you have in mind cannot be done with surety. Bob Fenner>

Natural ponds Date: Sun, 6 Mar 2005 Can you recommend a book that looks at constructing a pond in the most natural ways possible, i.e. without concrete or plastic base, maybe just working with stone or clay, non-electrified filtration or aeration ideas etc..? Thanks. <For one: Earth Ponds. Bob Fenner> 

Aquatic Gardens Ponds, Streams, Waterfalls & Fountains: Volume 1. Design & Construction Volume 2. Maintenance, Stocking, Examples V. 1 Print and eBook on Amazon V. 2 Print and eBook on Amazon   by Robert (Bob) Fenner