Pond Boss Forums POND CONSTRUCTION Soil questions Soil tests in excavated pond

A friend of mine decided to rent a dozer and dig himself a pond. I went out and collected dirt samples after a brief discussion with Mike Otto on what the soil looked like. These are the samples prior to adding water:



It looked like some red clay, some dark clay, and there was even some greyish-blue clay. However, after adding water around the samples, I learned otherwise:



Most of the samples pretty much dissolved/ fell apart immediately. While there is some clay content, it seems to be mosty a sandy loam kind of soil. We thought about disking in some bentonite and packing it down. We all actually work in the oilfield and were thinking of using drilling mud, which is bentonite. Anyone have any luck or thoughts on this project? The idea of bentonite was reinforced by Mike's lastest article. Thanks!

Here are a number of links to prior discussions on bentonite and methods to stop pond leaks. Several note the use of drilling mud in various methods. See the first link for our successful use of drilling mud.

http://www.pondboss.com/ubb/ultimatebb.php?ubb=get_topic;f=20;t=001709
http://www.pondboss.com/cgi-bin/ubbcgi/ultimatebb.cgi?ubb=get_topic;f=20;t=001716
http://www.pondboss.com/ubb/ultimatebb.php?ubb=get_topic;f=3;t=000081#000003
http://www.pondboss.com/cgi-bin/ubbcgi/ultimatebb.cgi?ubb=get_topic;f=20;t=001522
http://www.pondboss.com/ubb/ultimatebb.php?ubb=get_topic;f=20;t=001522#000001

shawn, i havent checked out ewests links which undoubtedly provide the info you need, but just thought i'd chime in on yer situation. first, if needed, tilled and compacted bentonite would be fantastic if your resources can handle it (maybe you have a good wholesale supply?). Regarding yer pond substrate soil, a formal lab test (sieve analysis) takes all guess work out of it, and will help you decide how much bentonite you'll need to shift your pond substrate to a clay dominant soil.


second, just a little about your dirt. Based on your test results, its interesting how much variation you have in pond area. How long did you let the samples sit in water after mixing and before taking picture? The one on left appears like a clay dominant soil, it’s the only one showing colloidal suspension. perhaps you can salvage excavated dirt from this area to add to the other areas. The others clearly settled out and are likely silt (plus or minus sand) dominant soils.

in general terms for anyone trying to identify what they have........sand, silt and clay are the three primary types of particles that make up most soil. A laboratory sieve analysis tells you exactly what percentage of each is in your soil. for a SWAG in the field, sand is obvious, you can see and feel the grains. clays and silts are trickier, especially silt soils, moisture conditions can make one seem like the other, but there are a few things you can try in addition to a water/jar test. (1) wet a handful of dirt (from each of your different areas) and make a ball in your hand, roll it around and twirl and squeeze out a thin thread. You have to work it a while, make it pliable before trying the thread. if its clay you can twirl out the thread a ways before it breaks, the more silt it has in it, the easier the thread breaks apart. (2) with the same moistened dirt, you can roll out a little cigar shape and pull each end. a pure clay will stretch (i.e. it exhibits plasticity), the more silt it has, the less it stretches, pure silt has effectively no plasticity, the cigar just breaks. (3) another quick way i can tell a silt soil is to place a small piece between top and bottom of front teeth, rub it a bit between teeth, (grit = silt) .....if its mostly slick....its mostly clay soil, if its mostly gritty.....its mostly silt soil.

needless to say sand and silt dominant soils leak, while the clay dominant soils dont....(o.k. they just leak REALLY slow)...few people are lucky enough to have pure clay (Brettski :rolleyes: ) and do fine if their pond substrates are mixtures of clay with sands and silts, but the clay HAS to be the dominant particle in soil.

Good luck shawn

Shawn, a neighbor of mine is getting the truck drivers to dump the old mud in the bottom of his leaky water holes and turning them into first class ponds.

I have 3 "leakers" but we can't get the trucks to them.

Thanks for the help, everybody. The pictures were taken seconds to no more than a couple of minutes between adding water. Dave, like you, I hope to have a drilling mud haul off in the area that I can get some mud from. I'll keep everyone updated on the project. Thanks again.

Thanks for the help folks. Shawn wrote in for me since I am pretty unfamiliar with the whole pond concept. Not a whole lot of planning, just rent a dozer and dig a hole. I figured since me neighbor to the north and my neighbor to the south have ponds on the same old creek line, it would be the right spot. Will definitely be finding some bentonite though. Luckily I am a drilling engineer for an oil company so I should have some contacts that can supply me with some drilling mud or some bulk bentonite.

Thanks again for the help, I'll keep you informed of the progress.

Rob, my friend is using junk frac mud. It works and is free. As you know, they have to find places to dump it.