Is agricultural runoff a problem on the AT

[goodolelefty]

I'm about to start my thru hike and I got to thinking about agricultural waste (pesticides, fertilizer, ect) runoff in the water sources. The filter I have now will be fine against biological contaminates, but should I be concerned about chemicals? Is there a simple solution to this problem?

[Slo-go'en]

For the most part the AT travels along the top of the ridge and most of the water you find is from springs or small spring feed streams high up. You can't get much better water then that.

When you drop down into a valley with a large or major river or something flowing along a road, you don't want to drink from that no matter what you have to filter/treat it with. My rule of thumb is if it's too wide to cross in a couple of steps, it's too big to drink from.

[rafe]

For the most part the AT travels along the top of the ridge and most of the water you find is from springs or small spring feed streams high up. You can't get much better water then that.

When you drop down into a valley with a large or major river or something flowing along a road, you don't want to drink from that no matter what you have to filter/treat it with. My rule of thumb is if it's too wide to cross in a couple of steps, it's too big to drink from.

The too-wide rule is new to me. There are plenty of wide, safe streams up high. The fords in the HMW in Maine. Several in the White Mtns., eg. Cascade Brook. Sure, water from high up the mountain is (usually) better than water running next to a cow pasture or highway. But gravity does not work in our favor in this regard.

I only mention Cascade Brook because it's fresh in memory. Had to abort a (winter) hike there because I didn't think I could cross it safely.

[bigcranky]

Yes, it's definitely an issue in valleys. I avoid drinking from large streams and rivers at low elevations for this reason.

[Rain Man]

Yes, agricultural and residential and commercial chemical run-off is a special concern in various streams along the AT. Some have signs announcing that and even prohibiting swimming and/or fishing or warning not to eat fish caught in the stream.

The ATC posts this information (somewhere, check with them) and my guidebooks tell me which to avoid.

[rafe]

Good thread. Simple answer to the OP's question is, yes. It's a concern.

See, it's more than just walking. If nothing else, you'll spend a surprising amount of brain power on the issue of water. Which water sources to trust. The likelihood of finding water on any given mile or the next X miles. How much to carry at any given time. Dry camp possible? Time to carry more. Woods soaking wet from days of rain? Now you've got other problems.

The higher up the mountain, the better, at least there's no concern for agriculture. There's still some concern for wildlife using the stream (or the lakes/ponds/marshes that feed it) and of course humans or their pets. Trouble is, the biggest streams are down low. Streams invariably peter out as you approach the ridge or summit.

Always good to consider the terrain above, and in the vicinity of the stream. Where's this stuff coming from?

[Deadeye]

The too-wide rule is new to me. There are plenty of wide, safe streams up high. The fords in the HMW in Maine. Several in the White Mtns., eg. Cascade Brook..

I wouldn't call it a "rule" per se, but the bigger the stream, the more opportunities for wildlife to contaminate it. The closer to the source, the fewer opportunities for pollution in any form.

[Deadeye]

which is really meant to say no, agricultural runoff is not a big problem on the AT. Most water sources on the AT are upstream from the agricultural pollution sources.

[Dogwood]

Depends on who you ask. For me, Yes, agricultural areas are a major concern for biologicals, shart, pee, and chemicals(herbicides, pesticides, inorganic synthetic fertilizers, fungicides, etc) no matter where modern industrial commercialized farming is occurring. For the mega populated east coast and the mega used AT despite the idea that the AT is a footpath through the wilderness it abuts agricultural areas frequently. Saying the AT is routed high therefore no or low agricultural influenced run off in water sources is not a gamble I will always take consuming untreated drinking water.

[Hikes in Rain]

\ My rule of thumb is if it's too wide to cross in a couple of steps, it's too big to drink from.

New idea to me, as well, but as a water resource engineer, I think is a valid rule of thumb!

[Another Kevin]

Depends on who you ask. For me, Yes, agricultural areas are a major concern for biologicals, shart, pee, and chemicals(herbicides, pesticides, inorganic synthetic fertilizers, fungicides, etc) no matter where modern industrial commercialized farming is occurring. For the mega populated east coast and the mega used AT despite the idea that the AT is a footpath through the wilderness it abuts agricultural areas frequently. Saying the AT is routed high therefore no or low agricultural influenced run off in water sources is not a gamble I will always take consuming untreated drinking water.

Occasionally Dogwood and I agree.

The A-T is mostly above the farmland, so you're mostly getting water running into the farms and not out of them. But sometimes it dips into the valleys, and then beware! I also always treat the water, even up high, because you never know when you have beavers upstream. And a lot of springs are still surface water that happens to have sunk in permeable soil but doesn't have a long enough percolation path really to be filtered. Up high, I don't worry about chemical contamination with very rare exceptions, so simple microfiltration or chlorine dioxide seems as if it's plenty.

One of the exceptions: I don't drink from Surebridge Brook in Harriman. Harriman was once an industrial wasteland, and Surebridge Brook comes out of what was once a tailings pond. Even though the mines closed over a century ago, it's still full of heavy metals, especially at times of low water. (It also tastes vile.) Filtration won't help much with that. Ion exchange might, but I don't carry ion-exchange media.

[George]

the lower elevation areas of the AT often coincide with city water availability

if you want to worry about something make it ticks/ lyme

[Odd Man Out]

I was hiking in central VA where there are a lot of ridges followed by valleys, repeat. It was summer and the ridges were all dry so I had to be sure not to go up without a load of water. In one valley, I came to a creek coming out of a beaver dam by a cow pasture. I regretted having to fill up there, but figured I had no choice. I didn't have a good guide so I didn't realize that a mile later i would get to a nice creek coming off the next mountain. I dumped all my water and took the time to filter another few liters. Needless to say, checking your guide books can help. On the other hand, I'm not dead yet. The bridge at the beaver dam did make a nice picnic table for lunch.

[StubbleJumper]

I have taken water out of a wide variety of sources. Some are, quite clearly, mineral laden. You can see it from the colour of the rocks and from the deposits in a creek. You can taste it in the water (for those who have walked down to the Animus on the CT, you will know this...you can see the minerals. We drink a few litres from those sources, and we don't worry about it. Some of those minerals are probably good for us, and some might be bad for us, but the amount of minerals found suspended in a couple of litres is trivial.

Turning to OP's question, to what extent are rivers contaminated with ag runoff? In cattle country, clearly there is a potential bacteria load that can be managed with filters or Aqua Mira. But from the perspective of crop production, to what extent does runoff from fertilizers or pesticides matter? I would propose that a couple of litres of water from a river in a valley probably won't make a difference to your health. A bit of urea won't cause you any trouble at all. A bit of glyphosate won't cause you any trouble at all. The concentrations are trivial to begin with and your consumption is trivial (ie: a couple of litres), so don't worry about it.

[FreeGoldRush]

A bit of urea won't cause you any trouble at all.

Farmers are aware that these chemicals concentrate after rain because they all run downhill into drains. Some of the chemicals they apply work in the soil, so this is of concern to them. As hikers we drink water from exactly the areas where these chemicals concentrate. It would be super unwise to assume you are getting only a little bit of them. I own some land and have applied some of the chemicals before. The last thing I'd do is go looking for drinking water after putting this stuff on the ground.

[StubbleJumper]

Farmers are aware that these chemicals concentrate after rain because they all run downhill into drains. Some of the chemicals they apply work in the soil, so this is of concern to them. As hikers we drink water from exactly the areas where these chemicals concentrate. It would be super unwise to assume you are getting only a little bit of them. I own some land and have applied some of the chemicals before. The last thing I'd do is go looking for drinking water after putting this stuff on the ground.


You are aware that the human body naturally produces urea? The biggest risk of urea runoff into a watershed is not the immediate impact on water quality, but rather the inevitable algae blooms which follow. The wrong type of blue-green algae can be toxic. But small quantitiies of urea? Harmless.

Similarly, the most common non-selective herbicide used for agricultre in the United States is glyphosate. It's used on millions of acres of Roundup Ready corn and soy, and it's one of the least harmful pesticides out there.

I'm not an advocate for drinking river water, but frankly that's mostly about flavour rather than safety. A couple of litres of river water won't hurt anyone (in fact, my city's water supply is from a river with agricultural runoff, and the water is perfectly fine).