Lining a pond bank with rock can help with bank erosion and water turbidity caused by it.
Happened to be out yesterday and noticed a muddy streak of water heading off across the pond. It was a very windy day. It looked like the muddy streak was coming from somewhere out in the pond toward the bank.
Upon further examination the muddy water was in fact coming from a small portion of the bank which had exposed clay. The waves were washing the clay into suspension then the undertow current was taking the muddy water out in the opposite direction of the wind and waves. So what looked like muddy water coming in from the center of the pond was actually muddy water moving out.
Earlier this summer I had taken the backhoe and deepened this area of the pond shoreline. What originally was intended as a swimming area with a gently sloping bank lined with fine gravel (man sand) turned into a huge FA bed. I also found we really liked swimming off the dock instead of the bank anyway. So this area was deepened. Most of the near shore was still rock lined though.
But in one small area the backhoe had come close enough to the high water line that clay was exposed. This small area was where the turbid water was coming from. Took the loader and sprinkled 2-3" rock out into the water in this area and shortly the streak of muddy water was starting to go away. The rocks were breaking up the water and discouraging the clay to go into suspension. Problem solved.
Point is, rock lining around a pond shoreline will definitely help with pond turbidity if the pond is exposed to wind and the dirt or clay is prone to suspension. My shorelines covered in rock are slowly becoming vegetated and eventually will not even visually be able to tell the rock was ever there. But it will still be there, below the roots of the plants, in case wave erosion tries to dislodge some of my bank.
Thought some might be interested in the pictures. The first and second pictures are of the bank area showing the turbidity caused by the erosion (003 and 005). The last picture (004) is a portion of the bank a few feet away where the rock is properly protecting from erosion and showing clear water like it should be.
Without the rock lining the shore line I'm satisfied that at least part of the time I would have a muddy looking pond. Just this small 3' of unprotected section with the waves pounding it was causing a significant streak of muddy water flowing out toward the pond center.
Here are a couple other threads concerning lining the bank with rock or rip-rap. Some like it, some don't. Having read these in the past was what caused me to think of doing the above post just to show how in some cases rock lining the shore line can be helpful.
Here is an update. When I sprinkled the rock in the water to stop the bank erosion and resulting turbidity I could see results within minutes. Within hours the pond had mostly cleared up with the bank no longer adding suspended clay.
When adding the rock, the water was muddy so I could not see what I was doing. By just gently tapping the loader bucket controls while moving forward was trying to spread a thin layer of rock over the bare area.
The two photos below were taken today around noon or about 3/4 of a day after adding the small area of rock (only the width of the loader bucked or about 6').
As you can see I did not get perfect coverage. There are still some clay spots bare but the bare spots are not very big. No wind today so the water is very clear and easy to see the added rocks. What I want to show is that even though I did not get complete rock coverage, there was enough rock to break up the current created from the wave action to stop the erosion.
When scuba diving in high water current situations divers quickly learn to not burn up their air supply and energy by trying to swim against the current. By ducking behind a coral head or any obstruction on the bottom, the current is broken up and the water travels above the tops of the obstructions. Same principal with this rock on the bank. Even though there is not perfect coverage, the rock that is there was enough to break up the current and make it travel a couple inches higher above the clay.
I'll go ahead and put a little more rock there now that I can see what I'm doing. But I wanted to show that even without complete rock coverage, the rocks were doing their job by breaking up the current caused by the wave action and stopping the resulting shore line erosion and water turbidity.
PBer's, In your experience (and opinion), does smaller size ( < / = 1"), medium size (1 -3"), or large size (3-5") limestone work best at keeping turbidity to a minimum around your pond? My ryegrass is coming in, but I'm still having an issue with erosion from the clay banks.
Average wave size would determine rock size...heavier wave action will mean heavier stone needed. The steepness will matter also...a shallow slope, the waves break easier...sharper slopes, the waves will crash into harder.
Thanks, Rainman...the local aggregate yard sells it in 3 different sizes (listed above) and I was unsure of which way to go. I think the smallest size offered will work best for my little pond. We don't get much wave action up in the piney woods. I think the smaller size will pack down better as well.
The finer stuff will tend to wash down the bank worse, especially on a steeper bank. Stuff too big is hard to walk on.
What I like to do the best is put a thin layer of larger rock, as thin as a single rock thickness. 2-4" stuff I like best. Then a layer of finer stuff over the top. 0-2".
Like was said, if the bank is steeper, (steeper than 4:1 in my opinion) you might want to make a "curb" where you want the rock to stop at, or it might just find it's way to the bottom of the pond.
If you don't put down geotextile fabric under the rock, it'll work it's way into the soil over time. Smaller rock will work in quicker than larger rock.
Larger rock, if below the waterline, will provide habitat and cover for invertebrates like crayfish. They will be able to hide between or under the rocks.
Smaller rocks pack too tightly together and don't leave room for them. I've seen RES making spawing beds on 3/4"-1" river rock beds.
PBer's, In your experience (and opinion), does smaller size ( < / = 1"), medium size (1 -3"), or large size (3-5") limestone work best at keeping turbidity to a minimum around your pond? My ryegrass is coming in, but I'm still having an issue with erosion from the clay banks.
Just for reference, the rock that I "sprinkled" into the water that you can see in the second set of pictures was mostly in the 2-3" range. It is what we use in this area for rock in the lateral drain field of a septic tank sewage system and is locally called "lateral rock" at the limestone quarry.
And Rainman, it is not hard to look around the farmstead and see places to use the "Tonka toys". But most of it involves "work" and I prefer the projects that are "play".
The banks of my pond are very gradual on 3 sides, however the dam side slope is a bit more aggressive. Most of my erosion issues come from the gradual sloping watershed sides. I'm going to have to make a decision and live with it. Thanks, for all the input. Im leaning towards medium size aggregate. I priced a 13 ton (dump truck) load of limestone for $600.00 delivered...does that sound competitive?
The banks of my pond are very gradual on 3 sides, however the dam side slope is a bit more aggressive. Most of my erosion issues come from the gradual sloping watershed sides. I'm going to have to make a decision and live with it. Thanks, for all the input. Im leaning towards medium size aggregate. I priced a 13 ton (dump truck) load of limestone for $600.00 delivered...does that sound competitive?
Sounds high for my area. We just had 40 tons of #2 stone delivered and spread on a soft roadbed, and the bill was far less than $600.
A lot depends on how far they have to truck it.
"Forget pounds and ounces, I'm figuring displacement!"
If we accept that: MBG(+)FGSF(=)HBG(F1) And we surmise that: BG(>)HBG(F1) while GSF(<)HBG(F1) Would it hold true that: HBG(F1)(+)AM500(x)q.d.(=)1.5lbGRWT? PB answer: It depends.
Sparkplug, They are a local outfit...they indicated that there would be no delivery charges. Maybe, I need to do a little more investigation on the subject. Thank you, for your input.
Rainman, I've never purchased aggregate of any kind in bulk and I'm ignorant of rock pricing. Thanks, for your and Sparkplug's candor. That's one of the reasons that I value this forum.
Is it true that a square yard of limestone is just over a ton in weight? This same business indicated that a 13 ton load of limestone would measure approximately 11 sq. yards. I have no idea.
Being an engineer, I could not help rising to this bait. Limestone comes in low, medium and high density sooooo..a 1 yard block of limestone weighs between 3000 and 4300 pounds. So the 2000 pound for aggregate could be close if it is low density stuff and then again size matters in this case!
Stickem, are you referring to square yards or cubic yards? Also, what size stone are they quoting you?
Last edited by sprkplug; 11/11/1407:59 PM.
"Forget pounds and ounces, I'm figuring displacement!"
If we accept that: MBG(+)FGSF(=)HBG(F1) And we surmise that: BG(>)HBG(F1) while GSF(<)HBG(F1) Would it hold true that: HBG(F1)(+)AM500(x)q.d.(=)1.5lbGRWT? PB answer: It depends.
Sparkplug, they were referring to cubic yards as in a load in a dump truck. They indicated a 13 ton load = ~11 cubic yards. Small sizes up to 5" for $600.00. Sizes 5" and larger $650.00 (same size weight load).
Bill D., interesting! Thanks, for crunching the numbers.
Now I see the cost. Ask them what the price on a load of #2 stone would be. My experience with stone "size does matter." The bigger the stone, the more it costs!
I'm with Bill, things make a little more sense now. I am a little curious when they say up to 5"....lot of room for interpretation there. What are they calling this particular size? (up to 5")
"Forget pounds and ounces, I'm figuring displacement!"
If we accept that: MBG(+)FGSF(=)HBG(F1) And we surmise that: BG(>)HBG(F1) while GSF(<)HBG(F1) Would it hold true that: HBG(F1)(+)AM500(x)q.d.(=)1.5lbGRWT? PB answer: It depends.
One thing that makes a lot of difference in the coverage a person gets per ton of rock is if it has fines or has been screened to remove fines.
Fines have their place. If a person needs the rock to "pack" finer particles are essential.
But a person will get more coverage, or in other words a bigger volume load, if the fines are removed. Rock with the fines removed is lighter per volume than the same maximum size rock with fines.
It is like filling a jar with marbles. When filled it will weigh a certain amount. But if sand is added and the jar shaken so the sand will fill the pores between the marbles, the same volume container will weigh more with the sand (fines) than without the fines.
Graded rock with the fines removed usually is higher priced per ton than rock with the fines included. For a road where it needs to pack using this cheaper per ton rock works well. But rocks with the fines removed will go further because there is more volume. The same number of tons in a truck load will result in a significantly larger volume load of rock with fines removed than with fines left in. It costs a little more per ton (because it costs to run the rock over more screens to remove the fines) but will have significant better coverage in applications where the fines are not needed or not desired. Cheaper per ton does not always translate to cheaper per project.
For bank erosion control the rock with fines removed will go farther. On the other hand, if the pond could use additional lime anyway (is acidic). Much of the fines will wash into the water with wave action and be of benefit.
Sparkplug, no I used the term "up to 5 inch"...they used the term "5 inches and smaller"...there are many aggregate sizes; > 1", 1 to 2", 2 to 3", 3 to 5" and larger.
Sparkplug, no I used the term "up to 5 inch"...they used the term "5 inches and smaller"...there are many aggregate sizes; > 1", 1 to 2", 2 to 3", 3 to 5" and larger.
While I've never bought stone in Texas, I will admit to being baffled by this particular grading system. Here, stone is bought by the grade, or number. The larger the number, the smaller the stone GENERALLY.
For a new driveway, I like #2 for a base (average around 3-4" or so), and then top dress it with #8 (3/4-1"). #11 is about the size of a fingernail.
"Forget pounds and ounces, I'm figuring displacement!"
If we accept that: MBG(+)FGSF(=)HBG(F1) And we surmise that: BG(>)HBG(F1) while GSF(<)HBG(F1) Would it hold true that: HBG(F1)(+)AM500(x)q.d.(=)1.5lbGRWT? PB answer: It depends.