MIDDLE VAAL RIVER UPDATE SEPTEMBER

Sheesh, it’s not been an easy winter!

WATER AND WEATHER

Base water temps are on the up, which means we are right on the edge of spring time action. Water is exiting the Barrage at 13 degrees this morning which means it should be circa 16 a few kilometers downstream: 16 is typically what it takes to send the fish into the shallow, faster water foraging for food.

Flows have been unusually high over the past 4 weeks or so: this is due to releases from the Vaal Dam sitting at 22m^3/s (normally around 10-15 m^3/s in spring before rains come) to dilute relatively high TDS (Total Dissolved Solids) levels in the Barrage (more here http://en.wikipedia.org/wiki/Total_dissolved_solids).

This high flow may result in a Yellowfish spawn as soon as water temps reach 20 degrees because yellows are triggered to spawn by a combination of flows and minimum water temp (water temp at dawn).

Visibility has been below expectation all winter, one of the theories is around high populations of diatoms (more here http://en.wikipedia.org/wiki/Diatoms) resultant from the floods last summer: regardless of the cause, clarity hasn’t been great and I don’t see it improving over summer with the increased heat and storm water run-off.

Hopefully the cold fronts are almost behind us and we can start looking forward to spring and summer weather. See the latest long range forecast here: http://www.weathersa.co.za/FcastProducts/ExtendedRange/MonthForecast.jsp

INSECT ACTIVITY

Finally the winter mayfly hatches have made an appearance (better late than never) although the fish did not really respond with much interest. Reports in from the past few days suggest flyfishers have seen increased mayfly hatches but only the odd fish making a real effort to capitalise on the easy meal.

The summer may hatches will kick-off soon and are often a combination of sizes and colours, you need creams, rust, olive, medium dun in a variety of sizes from 12-16, and don’t forget emergers!

Caddis hatches should start developing from now… be warned and arm your boxes with smallish cream adult patterns and lots of olive and green larvae and pupae. A report just in from Dirk Human in the Bothaville area suggests the first caddis hatch has come off, probably the large Hydropsychidae caddis (whitish cream adults, green larvae and pupae).

Oh yes, don’t forget the blackfly larvae, they are always around and the fish love’em! Basically they look like midge larvae, black and olive in colour and in sizes 16-20. The pupa are those little cone shaped cases on the rocks that look like caddis pupae.

APPROACH AND TECHNIQUE

Well if you dig nymphing you’re gonna love the next few months! Try to rely less on a yarn indicator this summer, you will develop more intuitive skills around where your flies are and what they’re doing and detecting takes, also fishing without an indicator allows for a more rhythmic approach to nymphing: Fishing into the swing at the end of the drift, fishing teams of soft hackles and fishing a lot closer in through the use of Polish/Czech/short line nymphing… trust me, you won’t be sorry… leave the yarn at home or in your pocket for a few months.

Thanks for your feedback via email. I know a lot of you had problems commenting on the blog, all is working now, it is easy and quick to post a comment, please do so! Your regular blog posts ensure everyone benefits from your experiences and not just me J

Yay, spring is on the way!

Keith

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email: keith@yellowsonfly.com

web: www.yellowsonfly.com

blog: http://yellowsonfly.blogspot.com/

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MIDDLE VAAL RIVER UPDATE AUGUST

The River is starting to stir from her slumber…

WATER AND WEATHER

New spills reported, facts not forthcoming: 2 alleged pollution related fish kills have been rumoured in the past week, 1 is immediately below the Barrage and the other on the Mooi/Vaal confluence: I have not spoken with any eye witnesses and do not know the size of the problem, or if there has infact been a pollution/kill at all. Keep an eye on the blog for more news if/when I get it (http://yellowsonfly.blogspot.com/ for those that are reading this report on the FOSAF website). In South Africa as a whole it is currently safe to assume that most municipalities are discharging untreated or under treated sewage into their local river: The fish are in the sh1t…it’s just the concentration that varies.

A survey has been undertaken to capture water user’s views on pollution in the Vaal River system, please visit the following link to participate: http://www.td-sa.net/.

On the whole, water conditions seem to be gradually improving through winter with clarity improving toward a meter in visibility in the upper region of the middle Vaal (between Barrage and Potch). Visibility in the lower end (Potch to Bloemhof) seems to be a little worse and rather inconsistent. I am not absolutely sure what is causing this: I have a theory that the discharge from mines and agriculture in this area has a large impact on water quality this time of year because of the lower flows and therefore lower potential for dilution… but that’s just a theory… (see 1^st paragraph in the report for an alternative theory)

The past week or so has seen slightly warmer air temperatures which have translated into warmer water temperatures and in turn the fish seem to have been a little more active with a few fly fishers reporting some action over the period. Water temperatures climbed by over a degree at the barrage outflow in the past week and a bit which took water downstream of the barrage close to 14 degrees in the shallower pieces of this part of the river.

It looks like we are in for another hefty cold front this week which should take us back to the typical 9-12 degree water temps for winter.

On the whole it is likely that we will have an early spring as both meteorological forecasts and animal and plant behaviour corroborate the view: Plants and trees are budding already, peach trees in some areas have been blossoming for weeks, black wattle are almost all yellow with flower, masked weavers in my neighbourhood have been building nests for the past 2 weeks …hopefully this is a good omen for the Vaal and a really good spring season.

Flow rates are still pretty steady at around 15m^3/s with occasional blips to 20 or 25. You may have noticed some higher flows on the DWAF Hydrology website; that was due to equipment malfunction. The Goose Bay and Schoemansdrif sensors are creating endless grief for the DWAF team in charge of this data, rest assured they know the information is important and make every effort to keep us informed.

INSECT ACTIVITY

Most of you probably find the discussion of aquatic insects at species level pretty unimportant: I have spent about 4 years now documenting the aquatic insect activity of the middle Vaal river and for that reason have been trying to better understand these bugs at least to Family and Genus level. In this process I ended up with a view (through misunderstanding some scientific literature) that Baetis mayflies do not exist in the Vaal River: Baetis is not synonymous with Baetidae, Baetis is a Genus in the Baetidae Family. Anyway, I was misguided, if you visit http://www.ru.ac.za/academic/departments/zooento/Martin/baetidae.html you will get a view of how this whole thing hangs together. You will also get a look at a few examples of what the winter mayfly nymphs in the Vaal look like. Slender nymphs tied mottled in sizes 14-18 are what you need.

Mayfly hatches have been coming off in slightly greater density in the past few weeks probably due to the upward shift in water temperature. But the insects remain pretty quiet; I think this might be due to the very cold weather, regular frontal systems and a river that is still stabilising after huge floods just 4 months ago. Hopefully it will all pick up in the next few weeks as we move into spring. Use this time to tie flies if you are not willing to brave the cold for the odd fish.

Tie lots of adult caddis patterns (12-16) for the caddis hatches that should start mid august and be at full speed in early September. Remember these insects hatch after dark on the hot days so as we move into summer don’t pack up when the sun sets… I usually get on the river at that time for a few hours of mind-blowing dry fly action without another angler in sight. Check out the Hydrolator on my website for a pattern that works for me and is pretty robust: http://www.yellowsonfly.com/News_Vaal_River_r.html

APPROACH AND TECHNIQUE

It’s tough at the moment, really tough. Guys are having the occasional good day with a few largies and smallies each, but this is rare at the moment. I won’t lie to you, this winter the middle Vaal has been unwilling to offer us the easy pickings of winters past.

For some insight on technique peruse the previous reports for the winter months on my website at http://www.yellowsonfly.com/News_Vaal_River_r.html. the left hand navigation bar has links to downloadable reports in the archive.

Hang in there, it’s gonna get better!

Keith

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email: keith@yellowsonfly.com

web: www.yellowsonfly.com

blog: http://yellowsonfly.blogspot.com/

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