Pond Boss Forums POND CONSTRUCTION Selecting a site Pond near ag land - concerns?

I'm looking at buying a piece of land near some agricultural land and building a nice pond with largemouth bass, etc. I would not be able to control runoff in to the pond, so I'm wondering how concerned I should be about fertilizers, herbicides running into my pond. I assume it has to do with how far the ag land is from my pond, so can someone tell me how far away is far enough, etc? There actually is an existing 1 acre pond on the land that I want to enlarge.

Thanks

Chet,

Ask the current land owner if he's had any problems in the past. Does he have any pictures of what the pond looks like during the peak of the season.

One of our ponds is a 2.5 acre pond that receives 100% of its water from a watershed that drains off a small dairy. That pond suffers from excessive nutrient loading, duckweed, watermeal and anaerobic activity. Not the ideal pond as far as water quality is concerned.

The level of intensity of your upstream "agricultural activity" is going to determine you water quality and the potential problems you might have.

Dig for as much information as you can before you purchase. If it seems that your "dream pond" is likely degredaded due to the upstream acitivity...keep looking for another piece of property to purchase.

My $.02 from first hand experience.

Chet:

There are three things I can think of to be concerned about with when you have a pond that has cropland for it's watershed: 1) fertilizer, 2) pesticides/herbicides, and 3) sediment.

As Trent pointed out, the condition of the existing 1 acre pond over the course of the (agricultural) year would probably be the best indication of how the runoff would affect it if you enlarge it. Anecdotal evidence would be better than none, pictures would be better (although even if they were digital pics with a firm date code, how do you know if they portray typical, good, or bad conditions?).

If the current pond does not have a problem with super-dense algal blooms from fertilzer (and hence possible eutrophication and resulting fishkill) or a big sediment input from runoff, you know that the existing buffer zone between the pond and the ag land has probably been sufficient to screen these two problem sources. Will your expansion of the pond reduce the width of the buffer zone? If this is the case, you could possibly improve the effectiveness of the buffer strip per unit width by changing it's composition. Tall, thick grass is a better buffer than short, over-manicured grass. Woodlands, which unfortunately take a long time to develop, are probably the best buffer strip of all. You might want to put in a sediment trapping pond or wetland upstream to catch as much of the three problem sources as possible before they can impact the main pond.

Pesticide and herbicide effects I am not very experienced with. Their presence in the pond would cause me to limit the amount of fish I ate from it. I think they tend to persist in the sediments on the pond's bottom; you could possibly have samples of the current pond's bottom muck analyzed for 'cide content. If the current pond has a healthy population of frogs, that is probably a good indication that there has been minimal 'cide application into the pond, as amphibians tend to be very susceptible to health and breeding problems due to these chemicals. OTOH, an absence of frogs could just mean the fish in the pond are eating them (bass especially). I think, but have no evidence to support, that a buffer strip or wetland that does a good job of screening sediment and fertilizer from the pond would be more effective at keeping chemicals out of it than a poor buffer would.

Another indication is what the ag land is being used for : past, present and planned future activity. Hayfields and pastures (which make up most of the watershed for my pond) have minimal impact - a fairly small amount of sediment washes off, they might get limed yearly at most (which would probably be a benefit to the pond), and they might get fertilized in one large chemical application per year or have manure applied round the calender. Manure (and, I think, fertilizer) during growing season will have very low impact on the pond, while manure in Winter, especially if spread over ice/snow, could have a big effect. Pesticide application is probably nonexistent or very low (I only have to worry about this a little during my wife's annual Roundup Rampage - she is very good about not spraying close to the pond).

Conventionally plowed and planted fields will send all three kinds of input (fertilizer, 'cides, and sediment) into the pond. This ag use has the potential for the largest sediment input. No-till fields will have a much lower sediment input, but probably the largest pesticide/herbicide application. I personally consider no-till the least desirable ag use to have upstream from a pond, and hayfields the most desirable.

Do the fields have drainage tile that empties into the pond? These provide a direct shortcut into the pond for the three types of problems, which I don't believe could be compensated for with an above ground buffer zone. Heavy sediment, 'cide, and/or fertilizer loads heading for the pond through drainage tile would in my mind pretty much necessitate an upper sediment pond or wetland.

I do not mean to completely scare you off from ag land in a pond watershed. A mature forest is probably the best watershed for any pond to have, but I would rather have ag land for my pond's watershed than a ritzy rural subdivision (with massive Chemlawn applications and septic system discharge) or a golf course (IIRC, the heaviest chemical applications per acre in America).

Thanks Guys

As it pertains to ag chemicals running off into the pond, is the biggest concern for the health of the fish, or the health of the people who eat the fish? My intuition tells me that if I'm OK eating soy products that have had a direct exposure to chemicals, than should I be concerned about eating a fish who grew up in a pond 200 yards from where the chemicals were sprayed? It doesn't add up for me. Can you shed some light on this?

Chet, there's a lot more I don't know about agricultural pesticide/herbicide effects on fish and fish-eater health than what I do know. I would not be surprised to find that much of what I do "know" is wrong. But let me run down a few things I'm fairly sure of.

1. The chemicals may build up or remain in sub-pond soils for a long time.

2. Any that enter the aquatic food chain tend to be in higher concentration as you move up the chain - invertebrates would have a low level, forage fish more, predator fish the most.

3. The chemicals are legal to use on crops where their effects have been studied. The soy products you eat came from beans with chemicals used that (should have and I believe did have) had the effects of their residuals in the beans tested, and determined "safe" for the level expected to be present when harvested. But the affects they have on aquatic life downstream from the bean field is much less likely to have been studied, IMHO.

I would personally not be worried about the health of the fish - they're just fish. (What's that noise outside, why it's a mob of angry pondmeisters with pitchforks and torches, come for the heretic! ) So if I wasn't planning on eating any fish from the pond, it wouldn't bother me at all. If I was eating a few fish now and then (less than the local state guidelines for fish consumption, for example), I don't think I'd worry too much. If I liked to eat pond fish as much as I do (I'd eat BG twice a week if I could raise and catch enough), no way would I want a pond fed by a no-till farming watershed.

That's just my opinion and I'm no expert on ag chemicals. I'm not sure we have any here, if so I sure hope they'll post some info. We do have some real experts on aquatic chemicals, but I don't think most of those are also used in agriculture (although some are). Maybe our unofficial research librarian, ewest, can locate some published studiesof the effects of ag chemicals on fish???

theo quick answer here but I think for the most part I'm correct. No way to bioaccumulate herbicides/pesticides. That is with PCB, heavy metals, etc. Many of the chemicals used are also used for aquatic use and they could not get the labels approved without testing fish tissues first.

So I think the use of herbicides upwatershed would not be major concern however as Trent said if too much nutrients the pond might be in trouble. Here in the SE it can sometimes be a blessing b/c it helps lack of nutreint situation.

I would trust Greg's input on this 10 or 20 times as much as my own.

And that's probably giving myself too much credit.