Understanding Vaal flow rates

 

dwaf Capture

 

 

There are only three things that determines the regularity of our fishing trips to the Vaal. The weather, the flow rate and whether you obtained your partner’s permission well in advance. About the weather there is not much we can do and being situated on the Highveld, fishing whilst there is lightning around, is just plain suicidal. The flows even less so as a flow rate above 40 M³/sec makes it just not worthwhile – whilst it is possible to fish in flows of 40M³/sec you must remember that something happened to cause the flows to reach this level – more than likely rain in the catchment area which means that you will be fishing in dirty water.

The flowrate above the barrage, or between the Vaaldam and Barrage is determined by the level of the Vaaldam as well as heavy showers between the dam and the barrage. The flowrate between the Vaaldam and barrage remains relatively constant throughout the year.

 

Below the barrage – Middle Vaal-

 

Firstly though it is important to remember that flows above 40M³/sec below the barrage does not mean that there are high flows above the barrage.   (The barrage is situated close to the N1 Highway crossing the river). 

The outflow from the barrage during spring/summer changes on a regular basis as different sized gates are opened determined by rainfall, the barrage level and individual water needs further down the river. During Autumn/Winter/early spring the flows remain mainly constant between 10M³/sec and 25M³/sec (May – Oct).

To obtain the daily flowrate there are two sites that one can use.

Firstly the daily barrage information supplied by Rand Water and the Department Water & Sanitation accessible at: http://www.reservoir.co.za/

Once you have opened the home page clicking on “Hydrology” and “Daily Flow” will open a calendar where you can monitor the current week’s flows.

 

 Daily flow 14 Jan to 20 Jan

 The top blue section shows the current flows indicated in the second line and should be enough for the general Vaal river fly fisherman to determine if going to the river will be worthwhile or not.

 

yellow line

 

Let’s quickly look at the attached picture and determine whether it will be a good idea to go fishing on 21 January 2017. We can see high flows of between 59.4 M³/sec and 74.2 M³/sec between 14 January and 16 January. Of course this is a no go as flows above 40 M³/sec becomes dangerous.

For the period 17 – 20 January the flows are decreasing daily from 29.8 M³/sec to 10.69 M³/sec. taking the above into consideration it is rather obvious that one can venture down to the river the following day. (*Note: Water released from the barrage takes about a day to reach Parys.)

Always remember that in the lowest flows you will always find deep pockets that will hold fish and of course wading is not a problem. High flows are dangerous and fish tend to go of the bite whilst waiting for the strong flows to normalise.

 

“But did they open a gate last night or this morning?”

 

geel streep 2

 

 

Flowrates are published on the Reservoir website at 07:00 every morning thus it is important to know whether gates were opened or closed before you decide to go to the river. If at 07:00 you see that they have opened gates and the outflow is now above 40 M³/sec I would strongly advise staying home and tying flies or watching the week-end game. (Unless you will be day fishing below Parys).

Looking at the second blue section of the Vaal Barrage information on the picture indicates the number and size of gates currently opened. My golden rule is that if the outflow in column three is below 40 M³/sec for the day, as well as the previous day, we should have a good day.

From this we can see that 17 – 20 January would have been perfect for fishing although you might have to contend with dirty water due to the heavy flows between 14 and 16 January.

 

Department: Water & Sanitation

 

To cross-reference your information you can also look at the information published on the website of the Department: Water & Sanitation. Here you can access the flowrate station situated at Goose Bay Canyon which is between the popular Yellowfish Paradise and Eendekuil.

http://www.dwa.gov.za/Hydrology/

and clicking on the Unverified Data and Forecast link.

 

 

 

forecast link

 

Vaal River flow rate

 

 

Clicking on Station C2H140 should give you the real time flowrate for the “Vaal at Goose Bay Canyon”.

 

Vaal river flowrate

 

At times it might be worthwhile to cross check your information on both sites as the Stations can sometime misbehave as shown between 19 and 20 January when the outflow from the barrage was 29 and 10 M³/sec respectively for the two dates.

 

What have we learnt?

 

Flows above 40M³/sec and rising can be very dangerous when fishing the Vaal river.

My personal experience is that if you want to have an enjoyable day’s fishing on the Vaal you ideally need to fish in flows that has been below 40M³/sec for two or more consecutive days as well as to check the reservoir site at 07:00 on the day to make sure that no extra gates were opened during the morning.

 

 

yello23

 

What do I do if I NEED to fish?

If you desperately need to fish and the flows are misbehaving there are always venues above the barrage that are not affected by the release of water. The flows here are pretty constant unless there was a sudden massive downpour or they have opened gates at the Vaal dam wall.

For places above the barrage try:

 

Lekoa Lodge

http://www.lekoalodge.com/home

 Vaal Streams

http://www.vaalstreams.co.za/

 Vischgat

http://www.vischgat.co.za/home/

https://www.facebook.com/pages/Vischgat-visvang-oord/564402783629691

 

 

 

 

 

 

 

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