Pond Boss Forums GENERAL QUESTIONS Help Pond muck removing and deepening questions

Hi all
I'm lurking this extraordinary forum for a long time. Finally I ve decided to register and ask some questions.
This is my pond

Inlet pipe is in the right short side and can provide water only from june to september. It's also spring and rains fed all over the year. Water is very clear in winter and very turbid in summer. The only weed is Phragmites palustris all around the shore. After years I've finally found a way to get rid of nutrias and now I've replanted some waterlilies for the fifth time in 4 years hoping they will survive now that nobody will eat them.
It's 98x446', about 1 acre, with a depth mostly about 6-7'.
I think nobody has never dredge it in the last 40 years, so I'm thinking to do it as soon as possible (not so soon because I have a just surgically operated knee and my wife is pregnant of twins, my 3rd and 4th children ).
It's stocked with LMB, PS, CGC, Crucians, Mosquitofish and some bullheads.
I don't want to drain it for many reasons:
- here (Italy) fisheries have only LMB, BH and CGC. No way I will never find sources to restock forage fishes.
- I don't have another pond (neither my neighbors) to temporary stock my fishes.
- All the farm is on a flat land, so it will be very difficult to drive away all that water.
- I've already spent a lot of money and time to get the pond stocked with those fishes. Initially (about 15 years ago) the pond was populated only by PS, carp and crucians.
- Finally now I have good sized LMB, BH and PS's population.

So my thought is to rent an excavator with long reach arm to remove about 4' of muck and silt from the bottom of the left half of the pond.
I will dredge only half pond this time to permit fishes to avoid as much as possible the muddy water that surely will blow.

I have time and I'm open minded to all your thoughts and advices to be fully prepared to do the right things when the right moment will come.

Thank you

Welcome Filippo, and congrats on your twins.
I know nothing about dredging ponds so will wait with you to see what those with experience have to say.

Cmm

Filippo, can you let us know what you mean when you list carp and crucians separately? Are crucians smaller carp?

Is there power (electricity/hydro) there or would you have to have a aeration system running by solar power?

Do you think if you removed 6-7' of silt/muck you could open the pond to a 12 or 14' depth?

Dredging will also lower the water level. You will lose the wet muck and some water with it. Siphoning will do the same. Do you have other water sources?

Welcome Filippo I have done this long reach excavating on my ponds several times. You will find that digging on one end of the pond will muddy the water in the entire pond within a few minutes. The action of the machine will mix all of the water. The biggest risk I have seen is if you have under water plants or algae growing in much of the pond they will be covered in silt and die back. The plants decaying will cause the oxygen level to drop and you will loose your fish starting with the largest ones first. You will see this within a few days after digging. You should be prepared to loose some fish if you do this.

That said if you can dig before the plants start to grow you may avoid loosing some fish. Colder water holds more oxygen so spring or fall is best. I would only dig maybe 25% of the pond at a time.

Next think about where you will put the mud you dig out. Your going to have more muck then you planed for and it may spread out like pudding depending on the soil type. Then hire the best operator you can find. The better the operator the more muck removed and least damage to the area.

It is scary to risk your fish, and I have lost some, but in the end the pond will be better for it.

Good luck!

@ CMM thank you very much. I'so happy about it. Finally, after two daughters 7 and 4, I will have two sons to play, fish, etc. with. Another good reason to make that pond better than now.

@ Canyoncreek sorry but I didn't know the english name of those fish so I've used google translator and the result was "crucian". Here we call it "carassio" and it's different (and smaller, max 2 lb) from carp as you can see below

There's no electricity near the pond and, for now, no aeration too.
I'm thinking about solar powered aerator, like I've seen here on the forum, but as it's so simple to get solar panels here as it's hard to find the rest of materials needed like the right air pump, sinking air hose, etc. because here there's no culture of farm ponds and fisheries, so nobody has the right equipments, knowledges and materials for pond managing.
About the depth I'm pretty sure I can reach 14-15'. I'm calm about leaks because a geological analysis has established that there is a layer of 60' of clay.

@ Dave and Woodster unfortunately the only abundant and manageable water source is the one provided for irrigation and it's available only from june to september. My thought would be of dredge on early september and leave all the sediments piled on the fields around the pond for about a week just to let them dry enough to be easily loaded on a dump and trasported on an uncultivated area. While dredging the left side I will keep open the inlet pipe (I will still have the water in the ditch) on the right side to:
- replace continuously the lost water
- add oxygenated and clear water for fishes
- try to push as much as possible the muddy water to the left side.
No problem for decay of weeds because at the moment I don't have any submerged plants or algae. The only weeds growing in the pond are 99.99% Phragmites palustris all around the shores.
I'm able to drive an excavator (I have a 30k lb FH, but with normal arm) so my thought is to rent only the machine without operator. Btw I've already asked to some companies around and there's no one single operator expert on this kind of work just because nobody asks for it. So sad but true.

Meanwhile many thanks for your useful and appreciated tips

A pic of last april, just to let you see the water color in early spring


This is august



I'll post brand new and major detailed pics as soon as I'll be completely recovered from knee surgery.

This is november water
https://www.youtube.com/watch?v=cA01IoWKtvg&feature=youtu.be

I have another question.
The muck/silt removed, which remained underwater without oxygen for so many years, what features does it have? I mean, you can spread it on fields or crops may be affected?
In the case it is not harmful, I must wait until it is completely dry or can be spread also wet?

From what I've read in other posts, it seems a lot of people spread the muck on farm fields and then mix it with the existing soil. I don't think it matters whether you spread it wet or dry although it will be like thick soup/pudding when wet and will be difficult to move.

Thank you Bill.

About water turbidity in the hot months can you tell me if the situation will improve by increasing the pond's depth and adding some submerged weeds like American pondweed and eel grass?

Why does the water get turbid toward the end of summer, especially when the water coming in slows down? I could see it if you got lots of rain/watershed, that brings turbidity.

Could the fish you mention, "carassio", be doing this? As the water warms they become more active and stir the bottom up. Are they bottom feeders?

Could the turbid color actually be a form of brown colored plankton?

Do you get stronger winds into the fall time, where it would stir up shallow water? Deepening might help with that.


PS. Do you still have carp in the pond? They stir up the water. Catfish will too if you get to many in there.

Hi Fish n chips,
surely carps, carassi and cats stir bottom up from spring to fall. I think carps above all, because carassi and cats are smaller and fewer (cats are not channel but a species that grows up to 1 foot). LMB feed on fingerlings of all three, so their population is large but stable.
LMB have been stocked 5 years ago. Carps, carassi and cats are in the pond from ever, so I think that over the years their total population will decline until a point of equilibrium.
Rain/watershed do their part; weather events in recent years have focused and have become more intense, so when it decides to rain, a lot of water flows to the pond rich in nutrients and soil particles. As rain is wind. In the last years happens that after several days of calm could arrive 2-3 days of strong wind, but this happens in every season, so I dont think this could be a turbidity cause.
Surely the pond is rich in nutrient from fields and fishes waste and without other weeds except shoreline Phragmites maybe they cause phytoplankton blooms. I dunno if it can be brown.

Yes, I have read it can be. Bill Cody would be the guy to get answers from on this. If I recall correctly, there are a few forum members on here that experience this on a regular basis.

Seems like the turbidity is caused either by the watershed coming in or the bottom feeding fish. Anyway to create a green space that would filter the water where the water flows in? Looks like you might have a "ditch" that feeds it, which would be impossible to control the sediment there. If that's the case, you might have to just live with it.

I doubt that dredging will fix the turbid waters. I am not saying that your pond wouldn't benefit from it, just that you need to find the cause for the turbid waters (if its not phyto) and address that separately from the dredging.

You're right, the pond is fed by a ditch. I keep it covered of grass hoping it could "filter" some nutrients and sediment along the way (it s a 1.3 miles long ditch starting from the main canal to the pond).
No way I can create a bigger green area before the pipe to let the incoming water filter.
I will deal with turbidity after dredging then, if water won't become clearer after it.
However I d like to hear about by others who have the same brown issue. If they won't appear here I'll try to search the forum.

Plankton blooms can be shades of olive to brownish due to numerous different algae. The "carassio" fish, as the food becomes limiting, could be 'working' the sediments stirring up sediment nutrients that help feed algae causing the bloom. Some algae species bloom at different times of the year.

Lurking around it seems that phytoplankton is green, zooplankton is brown. But also dead phytoplankton and some other kind of phytoplankton is brown....
Is there a way to understand what s my brown bloom is?

Thank you Bill for your reply.
What can I do to limit these blooms?
Do muck removal and deepening can help?

the fact that the pond is very narrow and very long may help you. Could you get about 100' of plastic sheets or a roll of vinyl, or the vapor barrier sheet that they wrap houses with that is 100' and use that to divide the pond into one section that is 1/3 of the pond and leave the other 2/3. Then have the excavator work on 1/3 of the pond. The majority of the stirring up of the bottom and exposing water to silt could stay in that 1/3 until that section is done, then let that silt settle, then divide the pond into another small section this time with 2 of the sheets 100' long?

If you startled the fish out of the area you were working to the other side of the pond, then sectioned off that area, would that not limit some fish damage?

Maybe in real life this plan wouldn't work due to depth of the pond...

This could be a good idea CC. I could find a PE sheet in various measures here, but I should find a way to keep the underside firmly planted in the uneven bottom of the pond and the top side floating.
The best method that I found time ago looking online would have been to hire an inflatable rubber dam, putting it in the middle of the pond, pumping the water out of the half I want to dredge, rescue the fishes to the other half and go dredge it. But no one has it to hire in Italy and buy one online the size I need would be too expensive for my pocket.

Do you have any Secchi disk readings for the pond clear water vs bloom water preferably on a monthly basis? You can make a homemade Secchi disk using any white disk around 20cm diameter.
http://www.secchidipin.org/makedisk.htm
http://www.mathinscience.info/public/0%20How%20to/oceanography_studies/secchidisk.pdf

Using Secchi Disk Note the disk does not have to be black & white
http://rmbel.info/how-to-use-a-secchi-disk/

The bass appear healthy and can obviously feed well enough to have good body condition. Unless you are having fish kills due to plankton bloom crashes then I would not be too concerned with the bloom. Blooms are caused by the correct balance of nutrients to feed that particular type of bloom.

Never thought about this Secchi disk. I'll try to make a homemade one as soon as my knee will be ok and start making monthly readings with it.
I usually have some kills (never more than 7/8) all over the year, but I think it's normal (I can't assure they are caused by blooms). Except for this winter during which I ve lost a dozen of nice 15-18" LMB. They all appeared healty (no signs, no scars, good colors of body/mouth/gills) and I can't understand the death cause. The winter here has been extremely dry and warm. The pond level dropped to 4' from november to february, with only a two day long thin ice layer.
Maybe the warm climate in association with the low water level have caused such a reduction of the DO to kill some of the biggest LMB? Are LMB more sensitive about DO than CGC? In the pond there are carps much bigger than LMB, but no one died.

We just had our pond "mucked out" a few weeks ago. We had to repair the dam which was leaking, so the pond wasn't much more that a bog really. Even still, the "muck that was taken out had the consistency of sludge. We dumped in in an old creek bed and it ran like lava. If yours is anything like that, you won't be able to pile it anywhere.

It's a flat land all around the pond and I'll dredge out muck and clay mud together. I hope this will help to keep all piled up as much as possible.
Last year I've used my own excavator to dregde out some dirt at 8' from the shore (that's the max distance I can reach with this machinery). There were not so much muck and the clay mud was really compact and full of Phragmite's roots. My thought about not many muck is that in shallow water bacterial activity is stronger due to the presence of more DO and/or that light and sludgy muck constantly slides towards deeper areas. Can be correct?

Yes, I think that is correct.

When I worked my pond and I got into areas of hard clay (and even heavy sand), the bucket really has to be forced into the clay to remove it. Then the muck is just pushed out of the bucket as the clay goes in (you will see this effect when you pour it out onto the ground too. The solids immediately go to the bottom and the muck just oozes everywhere) Now you might say that this is OK because the muck will just settle back into that hole and you will get it the next bucket full. However, half the muck will disperse into the water column and go everywhere, the other half that is in the hole will become so "fluidized" that it will be just like bailing soup out.

That was my experience, mileage may vary. This is why most like to dry the pond out before doing any digging. I get why you don't want to, just realize that it may be a lot harder process. I think you may want to start in the deepest area where the muck is, then don't dig into the hard bottom, but get a feel for where that is. Then lightly scrape that area. only taking the muck. After you get all the muck, then start deepening. I think you will need to always go back to the deepest areas (as you dig the rest)and remove the muck as it will slide and settle into those deeper areas.