Flyfishing Big Water

Big rivers present a daunting prospect for most anglers compared to the intimate nature of small streams. They have strength of character, impose barriers, and command respect, confronting us with varying degrees of intimidation, both physical and psychological. But while big waters may challenge anglers physically, emotionally and demand a wider range of skills, mixed with their magic of uncertainty they also provide great opportunity. Whatever it is that trout like or need, it is found in greater volume on big rivers.

While most New Zealand’s trout streams are not ‘as big’ on the world scale of rivers, we are blessed with plenty that engage the essence of big water, whether through the width of their beds, or the force of their flow. Fishing big waters presents very real problems of scale, access, and technique, compounded by genuine danger. It’s often tough to get an overview of what confronts you.

One of the key frustrations associated with bigger rivers is that, while they provide a greater volume of productive water, there are also significant areas of unproductive water to avoid. The art of recognising high percentage water and dismissing low percentage water is one of the greatest skills in productive flyfishing and is particularly relevant in any approach to bigger water. Firstly, a broad overview of the river is needed to narrow down the options and some simple things are worth doing that will minimize the legwork. Google Earth and topographic maps are very helpful. Field research on big rivers involves a lot of driving, looking for physical vantage points from which to visually assess the nature of the river; elevated roadside cuttings, nearby hills, and old logging skid-sites can all provide good river views.

On big rivers, there are often combinations of several ‘productive parcels’ in one area and a target hot spot is where the number of productive parcels is maximized and the distance between them minimized. These are worth searching for and on rivers with well-defined courses, prize water may remain relatively stable from year to year. However, on many of the South Island’s big, braided rivers, the quest for productive water generally begins again each season.

As with other angling, consideration of the habits of your quarry is essential and the key is to concentrate your angling on the prime water that gives the trout what it needs. Most of the time we are trying to catch feeding trout, so sort out the prime feeding areas. If you are trying to tempt trout that are not feeding (e.g. on a spawning run), sort out the prime sheltering lies. Fishing the right water will always provide a head start on those who may have impressive mechanical skills, but don’t take the time to study the water.

Arguably, anglers don’t simply fish a river, but rather approach it to fish different water types. That’s why reading water is the most elemental skill. River fishing, regardless of the size, is a combination of fishing the different ‘parcels’ of water comprised of runs, pools, riffles, pocket water, backwaters, flats, edges, eyes, and tailouts. Being able to identify water types and recognize their opportunities refines your approach and narrows the choice of techniques. This information needs to be further modified by considerations of the time of year and the fundamentals of water temperature, clarity, and flow.

Regardless of the size of a river, trout are very much ‘creatures of the margins’. As American author John Gierach eloquently puts it in Trout Bum (1986): “They operate at the edges of things: fast and slow currents, deep and shallow water, air and stream, light and darkness, and the angler who understands that is well on his way to knowing what he is doing.”

For the walk and wade fly angler, the most obvious limitation to water that can be fished is casting distance. Pragmatically, when the water exceeds wading depth, anything beyond casting distance is purely of aesthetic value. However, it is a misconception (probably born from the limitations of fly-casting distance) that on the biggest rivers trout avoid the central areas because of the weight and depth of the water and stick only to areas close to the structure of the banks. Aerial and drift surveys by Otago Fish & Game on the Clutha River (New Zealand’s largest mean flow) reveal that trout are quite evenly spread across most of the river, favouring, if anything, the centre of the river more during the daytime.

Surface flow characteristics do not represent a fish’s immediate holding environment. River trout in New Zealand generally inhabit moderate water velocities (0.2-0.5 metres per second) with recent research (Hayes) suggesting that brown trout prefer ‘on the nose’ velocity limits of between 0.2 - 0.3 metres per second but will move briefly to feed in water column velocities of 0.3 - 0.5 metres per second. These velocity ranges are safely achieved among the bottom structure of most of our boulder strewn, free-stone rivers, regardless of size.

The physiology of brown and rainbow trout is quite different. Rainbows are adapted to spending more time in the water column than browns and accordingly are better able to ultilise faster water velocities. This is reflected in the observed difference in distribution of rainbows and browns across a river, with larger resident browns particularly frequenting the shallower, quieter margins of a river, while rainbows stick to the deeper, faster water further out.

Deep holes and water over 4-5 metres looks very attractive to new chums, but it is what I regard as “one percent’ water. It presents serious practical problems for any fly angler to catch fish. While these areas may provide ‘shelter water’ for some trout, they are unlikely to support much algal growth (due to the lack of light to promote photosynthesis) and, therefore, don’t hold the grazing invertebrates that make up most of our trout’s diet.

Practically, especially where surface water velocities far exceed trout holding velocities, drag also makes it difficult for flies to sink deep enough or drift naturally in this water, regardless of how heavily nymphs are weighted. While modern sink-tip and sinking line technology offers some options, this isn’t top ‘feeding water’. Unless trout are visible cruising on the surface (generally only in slow currents) and present obvious opportunities for dry fly, emerger, or lighter weighted nymph tactics, I suggest skipping fishing these areas, although I regularly see huge amounts more time wasted on it.

There is a temptation with big rivers to take a more brutal approach than on small streams. But while there may be a bit more latitude in approaching the water, care still needs to be taken not to unnecessarily scare the fish. Any approach to a potential fishing area should be conducted quietly and conservatively, because the same rule applies -- “spook one fish, maybe spook the lot”. On big water that is likely to equate to a lot more fish, with the downside that, as mentioned earlier, it is probably going to be quite a hike to the next parcel of productive water.

It is generally harder to spot fish on big rivers, particularly on windy or overcast days because of the wider expanses of water and the frequent lack of a dark background. When it isn’t possible to spot easily, focus on any limited areas that have a backdrop of trees or high banks. The high banks are also useful for spotting with the advantage of height, which eliminates glare. Ultimately, however, to become a consistently successful fisher of big waters, an angler will require the development and refinement of good blind (imaginative) fishing techniques.

When stalking, spotting, and casting to sighted trout it often begs the question: “Did you simply spot the fish, or did your eyes confirm what you expected to see?” Mostly I suspect it is the latter, in which case intelligent blind fishing is a lot less about chuck and chance and more about testing an angler’s suspicions and aspirations. The better an angler gets at reading water, the more imagination can be applied and more successful they become. It is perhaps worth noting that the most successful blind fishermen I know are, without exception, also the best trout spotters. Both approaches are complimentary, especially when fishing big rivers.

The time of year significantly influences what types of ‘water parcels’ to focus on. Early season is the toughest time to successfully fish big rivers, with angling opportunity limited by high water levels, cold water temperatures, and difficult wading. Fish will tend to hold in slightly deeper water, so it is best to concentrate on areas of slower flows in the established holding water, such as mid-depth pools and big runs. The best places are where the river meanders and flows into features, such as bedrock cliffs and high banks, or along areas of riverbank stabilisation, with extended areas of willows or riprap. Big water presents the opportunity to use a much wider variety of techniques than is typical of small streams, especially downstream techniques.

Where the water depth is generally less than two metres (most river trout are caught from water that is less than 2m), standard heavy weighted nymphing techniques, using floating lines and indicators, will probably be most productive. However, where the water is deeper, or coloured, or if temperatures are cold (below 7C), time spent fishing streamer flies, using sinking line technology (from sink-tips through to deepwater express shooting heads), is also worthwhile. Sinking line techniques, using streamers and nymphs, can be effective on big waters throughout the season and more anglers should use them, especially when trout are clearly not evident in more easily visible shallow water. Development of a range of downstream techniques will also help extend an angler’s time on big water, especially when confronted with strong afternoon headwinds typical of most exposed big valley systems, which severely handicap standard upstream dead-drift techniques. Most anglers would also do better using heavier weight rods (#7 to #8) during the early part of the season to better cope with winds and heavy nymphs.

Bigger rivers come into their own as the season progresses and by mid-summer can become the hot spots in many areas. As river flows drop and water temperatures climb, fish become more active for longer periods and start spreading around. Areas of pocket water, most usually associated with the narrowing or gorging of a riverbed, will now be worthy of interest and expect brown trout at least to move to shallower water (0.4 - 1.5m). Floating lines, fished using heavy and medium weighted nymphs, will be productive. Look for the start of good dry fly action too, especially during the Coloburiscus hatches characteristic of most New Zealand rivers from mid-November through to mid-late December.

By January, the strong equinox winds that plague the exposed valleys of large rivers will have started to ease and, if an angler is lucky, they won’t become too much of a casting hazard until mid-late afternoon.

During the height of summer and early autumn when river flows drop to their lowest, more fishable water is exposed and many big rivers are less intimidatory. As they become more benevolent and easier to get around on, big rivers have real appeal, especially as fishing on small streams often deteriorates as their trout populations become stressed from low flows and warm water.

When water temperatures rise, focus on the prime feeding areas created by shallow riffles (sexy water). These are associated with ledges and drop-offs at the heads of pools and adjacent to deep runs and will hold good concentrations of active trout. Areas of a river that favour riffle development generally occur in association with the widening of the riverbed.

Another largely overlooked ‘productive parcel’, which frequently presents itself to the walk and wade angler when big rivers drop to their lowest levels, is found in any extensive areas of flat water that were unwadeable earlier in the season due to water depth and force of current. These large areas of flats are characterised by relatively even water depth and laminar surface flow and, in brown trout territory at least, are often favoured by good numbers of trout. The smallest fish will tend to congregate in small pods and are usually impossible to approach, but the better fish will spread and hold in association with any slightly larger stones or depressions in the substrate that create a break in the bottom current velocity.

Here the best approach is to work slowly and quietly upstream, zig-zagging across the water as far as safe wading allows searching for individual fish. Because these areas require stalking and spotting, success tends to be limited to calm, bright, sunny days with a high sun angle from behind and to areas with a backdrop of trees to facilitate spotting the fish. The smooth water characteristics created by the laminar surface flow require fine 5x-6x tippets (flourocarbon provides significant benefits in this situation) and small #16 to #20 flies, with my preference being small bead caddis nymphs or parachute dries. The prospects of stalking this sort of previously un-fished water in high summer is always a tantalising prospect. So, look for these areas during any early season excursions, making mental notes of potential prospects when the water level drops sufficiently. Good flats will often provide several hours of fishing in a relatively short distance for the careful and patient angler.

January to February is cicada time throughout most New Zealand regions and, where they exist, it is a special time of excitement and opportunity on big water, with many otherwise seemingly untouchable trout appearing. Fish will position adjacent to prominent current lines, and it pays to work those big dries along any tree-lined runs, or areas flanked with riprap and grassed banks. Often good feeding lines lie on the far side of the current from the angler and it is not possible to change banks to attack rising fish in the conventional manner. The problem with trying to attack any fish from a downstream position across a current is that there will be almost instant drag on the fly. An excellent technique in these circumstances (where it is possible to wade into a position upstream of the drift line and cast the necessary distance across the river) is to cast the cicada slightly downstream on an angle (30 - 45 degrees), incorporating an upstream reach and then start walking the fly downstream. It is essentially the same technique employed from a drift boat, without the obvious advantages of a secure floatation device … so be wary of any sudden changes in depth! With the inclusion of some slack line and regular mending, it is possible to achieve regular floats of 20 metres or more before having to re-cast. The bonus is picking off some trout that are usually safe on the far side of the current.

At the other extreme of summer dry fly fishing, big water also frequently provides wonderful opportunities for early morning spinner falls, when trout feed profusely on the fallen bounty in the slower waters of any extensive flats and broad tail outs. These trout seldom hold a position and actively range across wide areas, hoovering the small, spent mayflies off the surface. It is not uncommon to see a dozen or more trout on the surface at the same time, but success can be elusive. Small low profile dries, such as a Parachute Adams, or specialist spinner patterns in sizes #14 to #20 are usually effective. The secret is to target an individual fish, waiting until it rises before immediately dropping the dry fly only centimetres directly ahead of its feeding path. Long drifts are seldom desirable, because before your fly reaches the rising position the fish is likely to have moved several metres away again on another tack. Water that often appears smooth also can be notoriously difficult to maintain a drag-free drift for any distance. When trout come up on a spinner fall, they are seldom up for more than an hour (two at the most) and often much less, so casting becomes a precision game, if the angler is to maximize the opportunity.

A common problem on big open waters from early January to early March, is for water temperatures to quickly climb out of the productive fish catching range (11-17C). When the temperature climbs to 19C (which is not uncommon on big, braided riverbeds like Marlborough’s Wairau River between 1330 – 1530 hrs.), trout will very quickly go off the feed until the water temperature starts to drop again. This means successful angling is most likely limited to early morning or late evening.

Big rivers support huge caddis populations and prolific evening hatches are often a feature. This is a time when trout, that have been laying low under the shelter of the deeper water in the centre of large rivers, move into the shallower margins to chase hatching caddis. Once again, big water lends itself to downstream techniques and traditional down-and-across small wet fly (soft hackle) techniques can prove very effective in these circumstances, especially on trout rising in the more boisterous water, where it is not possible to keep track of a dead-drifted dry fly.

Because of their size, and because regular success will require improved blind fishing techniques, big waters start to place a premium on casting skills. I often hear the obviously self-limiting excuse that: “I catch all my fish within 10 metres anyway, so I don’t have to cast a long way”. But undoubtedly, improving your ability to handle a longer line will open up more angling opportunities on big rivers. If you struggle to cast a line longer than 10-15m, then swallow your pride and get some tuition…you will be amazed at the progress within even one lessons.

There is a point where rivers, particularly in their lower regions, become so big that bank fishing and wading opportunities become limited. Generally, these areas become the preserve of live-bait anglers or spin fishermen, but the fly angler, who can sort out a point and work a streamer fly down the current line and along the banks, still has an opportunity, especially early and late in the season when a few sea-run trout are present. As rivers grow in size, the use of a boat significantly expands opportunities and is ideal where access is difficult, or few bank or wade fishing opportunities exist. Over time, boats will play a bigger part in our fishing scene.

Success on big water is fundamentally about approach, not simply mechanics. Ultimately, successfully flyfishing big rivers depends as much on attitude as the depth of angling skills, and managing and overcoming the psychological intimidation is the priority.

An old timer once put it to me that when approaching a big river, “just think of it as two small rivers…one up either side”. While this is a bit of a simplification, his advice encouraged me to look at big water differently and gave me a focus. What this old chap was really suggesting was to minimize the uncertainty of big water by breaking the river up into familiar ‘parcels’ and then concentrate on what was in front of me. This is, after all, the simple essence of flyfishing any water.

“Most of the world is covered by water. A fisherman’s job is simple: Pick out the best parts.”

- Charles W. Waterman