Wednesday, August 02, 2006

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 1st 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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5 comments:

  1. Anonymous1:36 PM

    hi guys,
    Just realised it is a mare to post comments on this blog, I have fixed the problem, please go ahead and contribute. The more you add your views and experiences on the Middle Vaal the richer the forum for everyone.
    good fishing,
    keith

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  2. Anonymous4:46 PM

    Yes these past winter months have been rather unproductive ,but I am sure all that time spent on the water will pay off very soon as we have noticed a lot more activity around . The pollution spills are very concerning as I believe this issue has had a significant effect on our system and more importantly our yellows. Our great group of fishing buddies from Klerksdorp spend a lot of time further down ( Potch , Orkney , Stilfontein ) area .... Awesome fishing spots. Colin picked up a nice 7 Pd rubber lip using a carrot nymph last sat. The fish was in great condition, We will keep you updated on catches, condition and patterns. Thanks again. What are your views on these croc rumours going around ?

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  3. there were a few crocs located in the Klip/Barrage area, 1 was shot, the rest are "at large" as I understand it. But they are all around 1.5m long and above the Barrage: If you are crazy enough to actually fish in the Klip the crocs are the least of your worries :-)

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  4. Anonymous9:48 AM

    Hi guys any ideas on what the fishing will be like this weekend. in terms of weather conditions,flow,feeding depths,fly selections .... hope your nets honk of fish

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  5. Anonymous1:21 PM

    HI GUYS, I managed to put in 2 hours on the river this weekend. It was great landed two decent yellows of about 2 kg each. Conditions were good, warm slight wind, clarity about between 20 and 30 cm. Still not much surface activity. Was fishing the tail end of a relatively deep pool, casting across, down and a slow retrieve against the flow. I found that the takes were very slight , not aggressive at all ( maybe a strike indicator would result in more hook ups) First fish was taken on a olive caddis pattern behind a green stone fly , second on a carrot nymph.

    ReplyDelete