Monday, August 28, 2006

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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