How repair broken reservoir

Answer from: Junior666
You must increase the biomass in other areas, specifically underneath
The broken reservoir. You will get to a level where there are long roots
Hanging from the roof of the cave. Help these roots reach the cave floor by
Making sure no seeds hit the roots. Once they hit bottom the reservoir
Will fill with water and the soil will be suitable for planting.

Answer from: jr
To fix the broken reservoir, you need to do two things:

1. Go to the upper right-hand corner of the broken reservoir. There will be a gaping hole with wind coming in. This must be patched. Amani will suggest patching the hole with Bizanie membrane. You must visit another chamber with one this type of membrane and harvest a cutting. (If you don't first visit the hole and receive the message from Amani, you won't be able to take the cutting.) One you have the cutting, return to the Broken Reservoir and patch the hole.

2. After the hole is patched, there's no point in remaining in the reservoir or the Cascades chamber below. They will remain sterile until ... go to the Lethe Gorge and build the biomass up to level 2. Once you do this, the flood gates will open and both the Broken Reservoir will come to life and then you able to nurture organisms and raise the biomass.

Answer from: Andrew
First, go to the hole in broken reservoir that is blowing out wind.
Next go to Lethe Gorge. It will tell you to get Bizanie. Which is a jelly like substance that blocks some passages.
Go back to broken reservoir. The girl will tell you to get Bizanie.
Go to Canyon Vista to get the Bizanie.
Go back to broken reservoir. Patch up the hole.
Go to Lethe gorge. The roots will be moving downwards.
Push the seeds away that try to prevent the roots from reaching the bottom.