New Hinze Dam worries

[Brian D]

Hey, not knowing the full plan but hearing the trouble the NP is in with rotten vegitation caused by increased water levels, putrid water and lack of fish, what is going to happen to Hinze once the wall extensions have finished and the water level rises.

At Lenthals they stripped the trees to above the new water line. What are they going to do with Hinze, there is so much dence bush that the water will be rotten for years. I would guess thet can't leave the trees as this is the main GC water supply.

[nadders]

this may seem naive but is rotten vegetation a concern, i would have thought the natural breakdown of plant matter etc is a healthy part of the ecosystem

im not arguing just always wanting to learn, what problems does/will it cause?

[Brian D]

Nads have you ever experienced a dam roll over? That's when the bottom comes to the top and the top water goes down after seasonial and freak weather events. The dam shuts down for weeks.

With the rotten trees and grass in NP atm the water smells, has a funny colour and is very mercky. I hope this doesn't happen to Hinze.

[nadders]

Nah mate i am completely inexperienced in freshwater fishing, i don't know much if anything about dam mechanics lol.

the smell etc is surely jsut an aesthetic problem though right? i mean vegetation rotting and breaking down is a natural process i wouldn't have thought that fish would mind, maybe throw them off the bite for a while due to water clarity or whatever but it shouldn't bring them any harm yeah?

again not sure so please let me know if i'm wrong. just interested

[Davo_Dinkum]

i think the would know the rough water high of the dam at full.think the would keep it fairly clear.low number of trees that are kept cut back and low grass .that would have to help minimize the damage and yuck.

not sure how it all works .but have u ever had your yard flood and have water sitting on the lawn for a week or 2 .it stinks the grass dies it turns into a dirty smelly bog .

with some of the heavy rain and big amounts of rain and floods we have had this year.

with my back yard it was about 2 inches over 1/2 the back yard.

i end up having to dig trenches to get it to run off and took a few months to dry out and start to recover.

[bigtez]

I could be wrong, high school was a while ago and that is the last time I thought about this stuff.

The rotting vegetation reduces the amount of dissolved oxygen in the water and consequently the fish have trouble 'breathing'. They then go into survival mode and concentrate on seeking out oxygen and not worry about finding food as much.

Perhaps one of the experts could correct me if I am wrong.

[Davo_Dinkum]

i have heard that too bigtez.

[rayke1938]

All the trees and vegetation is to remain. The main reason is that it is too dangerous to remove it as the most of the country that is going to be submerged is very steep hillsides.

The hinze had a similar event last year when it went from below 40% to 100 % in a short period.

The fish just shut down for several months. From reports that I have heard it is pretty well back to normal now.

The hinze did not have a significant regrowth of vegetation that the NPD had during the drought as the water level was not down for such a long time and the steep terrain also helped.

Lenthalls also had a long shut down period even though they removed all the trees and vegetation and is also only coming back on stream.

Just my opinion.

Cheers

Ray

[Little Grey Men]

The rotting vegetation causes Hydrogen Sulphide which is toxic to the fish and depletes oxygen levels in the water. They seek out the best water which could be anywhere in the water column. When NPD had slight increases the fish would come in for a look around the new grass but would clear off when it started to rot. Just a waiting game I suppose.

This latest lot of water increases at NPD meant that a hell of a lot of vegetation has to break down, which is a slow painful cycle. One good thing is the amount of trees underwater means a lot more structure for us to fish in.

[nadders]

cool, thanks for the knowledge. hopefully it turns out ok

[Dinodadog]

nadders a classic case was when we were fishing from the bank at NPD a mate of mine wanted to take his 2 bass home, so he tethered them in the water and within 20mins they were dead from the rotting vegitation.

[roobs]

i was at wivenhoe and big W has a similar problem. even the snub-nose gar have all racked off. there were some bony bream about but they are known to survive in very low levels of oxygen.

[Brian D]

Well if the trees are to stay (as I suspected) then hinze is in for a huge change.

Currently there are heavy timber all around to above the water then nice grassy banks sloping down into the water with very little sunken timber. Once they raise the level 30% we'll be fishing in timber. It will be like Glenlyon ...find a tree and tie up to it.

You wont need an anchor for about 20 years. You won't be fishing off the bottom anymore, you will be fishing mid water above the tree tops. Maybe the togo will be the 1st to recover, either them or yellow.