S8, Ep 25: The Science of Stealth: Mac Brown on Fishing Techniques for Low Flow Scenarios

In this episode of The Articulate Fly, host Marvin Cash reconnects with Western North Carolina guide and casting instructor Mac Brown for another installment of Casting Angles, the recurring series focused on fly fishing technique and education. With drought conditions pushing water levels to July-like lows as early as April, Marvin and Mac make the case for thinking about technical trout fishing tactics now rather than waiting for summer. The conversation centers on two foundational concepts — Snell's window (the fish's cone of vision through the water surface) and the Rule of Six (a field formula for calculating safe approach distances) — and explains how understanding both allows anglers to grid a stream systematically rather than blindly targeting the most obvious foam lines. Mac and Marvin also touch on dry-dropper rigging for low-water flats, delicate presentation techniques including reach casts and horizontal rod planes, terrestrial fly selection, hatch conditions on Smoky Mountain freestones, and current fishing conditions on the Tuckasegee River.

EPISODE SUMMARY

Guest: Mac Brown — Fly Fishing Guide, Casting Instructor, and Owner at Mac Brown Fly Fish (Western North Carolina / Great Smoky Mountains)

In this episode: Guide and IFFF-certified casting instructor Mac Brown joins host Marvin Cash to discuss low-water trout fishing strategy during an early-season drought. Topics include Snell's window and the Rule of Six, stream gridding methodology, stealthy approach tactics, and current hatch and fishing conditions on Western North Carolina tailwaters and freestone streams.

Key fishing techniques covered:

• Snell's window and the Rule of Six — calculating fish vision diameter (depth × 2.25) and safe approach distance (angler height in the water x 6) 
• Stream gridding — systematically working a grid pattern across the full width of a stream rather than targeting only primary foam lines
• Reach cast — horizontal rod presentation to keep fly line out of the fish's feeding lane and reduce drag on dry flies
• Dry-dropper rigging for flat, technical water — using terrestrials (beetles, ants, crickets, grasshoppers) as the dry with an unweighted or lightly weighted nymph dropper cast well upstream of the target
• Stealth and camouflage — staying beyond the fish's window (generally 30–40 ft in slow clear water), minimizing overhead rod motion, and wearing muted/camo clothing

Location focus: Tuckasegee River (DH sections near Bryson City and Webster), Great Smoky Mountains National Park freestone streams, Davidson River; general application to technical freestone and spring-creek-style water

Target species: Wild and stocked trout (rainbow trout implied throughout; brown trout and general trout fishing)

Equipment discussed: Unweighted pheasant tail nymphs (sizes 16–18), micro caddis (size 18), midges (sizes 20–32), terrestrial dry flies (beetles, ants, crickets, grasshoppers), 9-foot fly rods; MacBrownFlyFish.com for school/guide/lesson bookings

Key questions answered:

• What is Snell's Law and how does it affect trout fishing approach distance?
• How do I grid a stream to cover water more effectively?
• What flies and tactics work best when freestone streams run low and clear in spring?

Best for: Intermediate to advanced anglers fishing technical freestone streams, tailwaters, and spring-creek-style water during technical or low-water conditions

FULL TRANSCRIPT:

Marvin Cash00:00:03

Hey, folks, it's Marvin Cash, the host of The Articulate Fly. We're back with another Casting Angles with the man himself, Mac Brown. Mac, how are you doing?

Mac Brown00:00:12

I'm doing great, Marvin. How are you?

Marvin Cash00:00:14

Just trying to stay out of trouble. Was the Easter Bunny good to you?

Mac Brown00:00:17

Oh, the Easter Bunny was great. We've had a. Had a busy week since we talked last and it's been good. It's been good. It's been getting a little bit warm during the day.

Marvin Cash00:00:26

Yeah, it's funny you say that.You know, I was listening to some stuff on the radio today and I mean, we all kind of know it because haven't seen any rain, that we're most of the states in a drought. I think I got another burn warning on my phone to not like burn anything outdoors.But you know, what that really means on the angling side is we're going to get to technical fishing earlier than we normally would.So we thought we'd talk to people about stuff that we actually do later in the season when the fishing gets more technical, like longer leaders, more delicate presentations and things like that.

Mac Brown00:00:57

Yeah, yeah, I think that'd be a good topic. And it's. It's definitely warmed up a lot quicker than normal.I mean, when I think back, even the school we did in March, we were out wet, wading in like 80 to 80, 85 degree weather in middle of March, you know, after we finished in Lancaster. So, yeah, it's been warm for a while. It's not just like just the last few days. I mean, we got warm fast.We came straight out of a cold winter and straight to high heat with not much transition time.

Marvin Cash00:01:25

Yeah.And so, I mean, we can talk about presentation later, but one of the things we were talking about before we started recording was basically the rule of six and Snell's.And so I thought it'd be really helpful, you know, to help folks out in terms of explaining what the rule of six is and talk to them about kind of how, you know, applying a little Snell's law can help them grid the water a little bit better.

Mac Brown00:01:45

Yeah, that'd be good. That'd be good for this time of year because it's definitely low. I mean, it's already low, you know, floating, floating out on the Tuck.The last last week and a half, it's been a. Like, the kind of water levels we see in July are happening in early April.So now, of course, because it's a tailwater, east and west fork, of course, they can adjust that, but I Think part of it is there might be political pressure from Jackson County Chamber or whatever to put on Duke to tell them, hey, we want really low water for all these tourists, can walk around easier. But I think it's also from the lack of rain, you know, so when it's that low, it just makes it a little bit trickier for one, getting rice down.But then the other problem that compounds that. Now you got low water to get the rafts down, and you got a ton of people standing in the raft routes, you know, so then starts to get a little crazy.Not so much down in Bryson because you got the Oconaluftee, Ravens Fork. But, like, if you're up in Webster, it does get a little crazy because there's only, like a specific raft route.And if five people are standing in it, how does the raft go down the water, you know?

Marvin Cash00:02:49

Yeah.And if we talk about, you know, Snell's law and the rule of six, I mean, kind of two things, the shorthand, you know, we understand that basically, you know, fish can see almost 360 degrees behind, and there's only a dead spot, like directly behind the fish. And so, you know, the question is, how big is that circle of vision on the surface?And the rough rule of thumb is, you know, for every foot of depth, you multiply that by 2.25 and that's how big the circle is.

Mac Brown00:03:15

Right, right. That's right.So if a fish is 2ft deep, you know, 2.25, you know, skinnier water, like what you're going to see out of the natural freestones, you're going to see a lot of water where the fish are feeding in the kitchen, which is the riffle. And you're talking 6 to 6 inches to a foot of water when they're in the kitchen feeding.So now you're talking about gridding off in a lot smaller quadrant, because we're talking about two foot cast. Two foot, two foot, two foot all the way across the stream, like where those. Not just the foam line, that's the problem.You know, for years with these guide schools and things, people think, would a fish sit in the cart, so they throw all their cast in one basket and ignore everything else.So they're fishing literally one little spot of current where there's current and 15 spots across the creek, but they're throwing it all in the biggest, sexiest foam line they can see. You follow me. So usually what they find in this part of the country and in New Zealand and everywhere that I've ever traveled Think about this.If a fish was a lot better quality fish, quality fish being big fish, which is ones people usually want to catch, I mean, they try to catch anyway. Let's say that a big fish can't sit there with 50 little rainbow in the same quadrant of a foam line.So if you got a really nice big foam line, chances are that's the majority of a bunch of smaller fish.Because where that bigger fish always is is off on a exclusive foam line that's small enough just to bring him or her the dinner that they can protect because the foam line is just big enough for them and them only.So that's what's funny about it because everybody that tends to throw in the main, the main foam line, where it's a four foot foam line of a bunch of numbers, a little fish, then you got a really quality fish sitting over there that's 25 inches in a little freestone and he's got it all to their self. That's why this whole grid. And off topic, I think that's a real good topic because the water's going to be lower a lot quicker than normal.And talking about the grid factor, so the grid factor just means running on the 2.25. You know, if you're fishing water three foot deep, what's your grid? And there's an answer to throw on that grid pattern.And I don't think a lot of anglers ever think about that. They just kind of chunk it out and hope for the best. And that's a, it's a good topic for a podcast, Marvin.

Marvin Cash00:05:31

Yeah, well, I try.You know, so the, the other thing I would say too on the grid thing is, you know, if you're fishing upstream, you want to basically fish back to front, close to far right, so you don't line fish. And you know, to your point earlier, what I always tell people is, you know, obviously there are better spots in the grid than others.And the way I try to compensate for that is if I have a place that I think is a better spot than another spot on the grid, I might throw a few more casts there, but I'm still going to work the entire grid.

Mac Brown00:05:57

That's right. And where it works really well too. Think about the, I mean, this is worth saying too about the grid line and, and speeds and getting good drifts and.Because we're going to jump into that in a minute with the rule of six.But this is where like let's say the current straight above you, the foam line, let's, let's Say it's, you know, only two foot big, straight above you. You could turn something over straight. In those examples, using a reach man, just reach it out of there.Because if you got your fly line sitting in the same current that you're trying to fish, there's a couple things going on. One, it's bringing your dry fly too fast because the water's going to move fastest up on the top, right?So if it's going to pull, if the fly line is going to help act as an extra pull, the dry flies getting pulled too much. The other thing is you got your fly line sitting on top of the fish you're trying to catch.So imagine throwing a cast 30, 40ft upstream, and all you do is reach the rod up to the side, just dig and lazy, make the cast and lazy, just throw the rod over to the side. And now your fly's in the current, your fly line's in a little bit slower current, and everything works out beautifully.And the fish that you're trying to catch don't see a fly line and a leader sitting on top of it. All they see is the fly coming down their window, the window of vision. Does that make sense?

Marvin Cash00:07:06

Yeah, absolutely.And, you know, you want to let folks kind of explain the rule of six and how that interacts with kind of the size of the circle we talked about earlier at kind of one, you know, one foot times 2.25.

Mac Brown00:07:17

Yeah, yeah. The way.The way I learned it as a kid was going up and getting frustrated, you know, getting too close, and now I'll see the shadows and realize right away I already messed up. Then you stay back a few feet further as a little kid and you realize, oh, I messed up again.So basically, when you start out doing this, before you understand it, you just mess up a lot. And you learn that you got to stay out pretty far. What's pretty far? So as a kid, you know, five foot tall kid times six, 30ft.So basically, your distance you're trying to fish is 40 to 30ft if the water's slow and smooth, because that way you're invisible to the fish you're trying to catch. At 40 to 30ft, you hadn't spooked them yet. But then everything 30ft and closer, if the water's clear, they've already seen you.It's hard to catch things when they already saw you, because what happens, they run to the next county as soon as you stepped up in the water within that window. So the window works by taking the distance to the fish's Window that we just talked about, that window is a circle.So if the fish is a foot deep, that circle is 2 and a 2 and 2. 2.25Ft around it. So the rule of six says, let's say that fish's window is 30ft away. Divide that by six gives you the answer number five.So if a rod's nine feet long, are you going to make that cast down to the side, like a horizontal cast, or you want to put the rod tip up vertical? Because now the line's coming in, you've already blown it because you made a bunch of motion up high.So the rule of six just tells you how far you can approach. And that gets really important when water gets technical and low, or spring creek with very low flows.Now, in a riffle, all this goes out the window if there's a lot of fast water. But what happens with all the fast water? When the water gets really low, the amount of fast water starts disappearing rapidly.So that's why all these things come about. So Snell's window, It's what we call the fish's window. This was all figured out long ago.So it's just a way to do it more from a science background of. Instead of just going out and trial and error and failure to figure out what works, you know.

Marvin Cash00:09:14

Yeah. And so I've got a couple blogs I wrote a while back. I'll link those in the show notes.But the other thing, too, to understand, folks, is that, you know, in that kind of circular field of vision, and what we're really talking about is the water bending the light. So if you kind of think about it, it's like there's a.A funnel of vision that comes up out of that circle that we're talking about on the surface of the water.But, you know, when trout see, one of the reasons why they spook so easily is everything that kind of the edge of that circle down near the water gets smushed. And that's why they're so incredibly sensitive to motion.So that's another reason why you really want to kind of be stealthy, you know, to max point, keep that cast in the horizontal plane and not make a lot of movement. And also, too, you know, wear a. A light green shirt or something that kind of blends in so you don't stick out like a sore thumb.

Mac Brown00:09:59

That's right. Yeah. That used to be a big. In the early years up here in the park, that used to be a big, really big thing.First thing, I'd send everybody back, you know, don't show up with some white or pink or light blue, you know, clothing, you know, and then people, sure enough, they show up with light pink and fluorescent colored clothing. And I'm like, oh, this is going to be a tough day. It just makes it tough.I mean, it's funny because most of the people that you know, like Jimmy Estes and all the different friends that I've, that I've met here that are really into fly fishing since like 1985 of when they go out west.You know, a lot of these anglers from Carolina, when they show up in Montana and Colorado, they're all dressed in like almost turkey hunting clothing. You know what I mean? They, they wear camo. They wear camo for a reason.

Marvin Cash00:10:45

Yeah, it works.And so I would say too, you know, just the kind of, the typical kind of technical water conditions, you know, is the water, you know, volume goes down, it's a lot smoother. So you want to try to avoid waiting if possible. Right. And then I would also say, right, you know, lengthen your leader.But it's also, you know, we were talking before we started recording too, that, you know, this is the place where like, you know, the dry dropper is really good because if you have relatively flat water, you basically have one shot and you can't really mend it. You gotta like, put it where it needs to be. Maybe you can cast past the fish and kind of lightly pull it online.But, you know, that's really kind of what, you know, you can't go out there with a, you know, quarter size Oros and start and think you're gonna catch fish in. In flat water.

Mac Brown00:11:30

That's right. And yeah, a lot of this, what we're talking about is probably more tailored right now for the.Well, it's tailored also for the dh, but definitely like the freestone, the technical stuff that happens like in the national park or the Davidson river or anything that's similar like that. But, you know, because they just put, you know, we talked last week and talking about the lack of fish in March.And sure enough, a week ago, Marvin, they put a bunch in and Bryson and Webster and everybody's Yahoo. Right now there's lots of boats. All of a sudden, the month of March. I mean, every time I floated, I'd see maybe one boat, if that.Now it's a different story.So now when you float in town, we're seeing about 15 to 20 boats, you know, because there's fresh fish and a lot of this stuff, it will still happen on these DH waters. But it's really paramount that it happens on the freestone stuff, for sure, like, already, because the water's already getting warmer.The water's already lower. So it's going to be like fishing in June and July and late April and May, basically. Because the water temps are already late June in April.

Marvin Cash00:12:32

Yeah. And I would say, like on the dry dropper front, you know, terrestrials for your dry, you know, double your chances.Beetles, ants, crickets, grasshoppers. The other thing I would say, too, is, you know, you gotta really watch the weight.So if you're fishing a weighted dropper nymph, the way to compensate for that so you don't have that plop that scares fish, is if you cast well above the fish you're targeting with less weight, you got more time for it to get in the zone before it gets to the fish.

Mac Brown00:12:59

That's right. No, we've been. It's funny you say that because that's what we've been using a bunch already is unweighted pheasant tails. Just unweighted small.16, 18. Because we're not seeing the March browns, the Hendricksons.All the classic hatches that I've been able to, you know, see here since 85, they're just not happening every trip last week. I was on the water with a trip every day last week, and we're seeing, like, size 20, size 32 midges, and that's it. A little bit of black caddis.That's like size 18, little micro caddis. And I'm like, where's the March Browns? Where's the Hendricksons? This is when they should be popping off.But, you know, I don't know if we'll see them at all, because I remember. I remember last year, I saw one hatch of Henriksen's the whole springtime.So it's not like people think, oh, Hendricksons hatch this time of year, and that people come up from, you know, like, Atlanta and think they hatch every day in big numbers. That's not the truth. You can sit out there all day long from sun up till dark and not even see one all day long.So the hatches are kind of been on a downward spiral for a lot of decades. So we don't have the classic hatches that we used to talk about back, you know, 30 years ago.

Marvin Cash00:14:06

Yeah, well, before we give away all our secrets, we probably should shift gears and let you talk about, you know, any upcoming schools. You got how to get a guide trip and how to get a casting lesson. Right.

Mac Brown00:14:15

Yeah. We just finished a two day casting weekend this weekend which was really fun. And yeah, there's another school coming up in March.I mean, not March, April 19th. And that's just in a. That's coming up quick next week. So that's another five day school. Yeah.So the probably the best way to get, you know, info is MacBrownFlyFish.com that'll have all the pertinent information and it'll have everything you need to know. Just reading that and go over on the menu.If you're interested in the school, go over and look at the, you know, the special class itinerary and that's where all those things are listed.

Marvin Cash00:14:50

Yeah. And we know no smoke signals because you got a burn ban in, in Swain county. So don't do that.So email or call Matt because he doesn't do the DM stuff on social media very much, right?

Mac Brown00:15:01

Yeah, that's right.

Marvin Cash00:15:03

Well, there you go. Well, listen folks, it's warming up.I would tell you, you know, if you're targeting trout, it's just going to get harder every day, you know, if we don't get a bunch of rain and I don't see any in the forecast. So you go at yourself to get out there and catch a few. Tight lines, everybody. Tight lines, Mac.

Mac Brown00:15:17

Tight lines, Marvin.