Ravil I try to answer your questions below.
1. What river is more interesting: Cotahuasi or Colca (Lunar Canyon)?
Both rivers are very interesting. I would suggest you do both. The Lunar canyon is not so long. Maybe 40 km total. I have done it in one day but also did ot very slowly and made it 10 days long with lots of camping and hiking. I think 3 days, 4 maximum for lunar canyon. The "Upper Colca" from cabanaconde is 3 more days but only good in kayak. It is too small for rafts with difficult portages.
- Is possibly start from Cotahuasi village and then portage Sipia fall? Or we need take the mules and go below Sipia fall?
Yes you can even start above Cotahuasi. A new road goes up Cotahausi so you can follow the road and start where you like and see the river. You can perhaps another 1-2 days above Cotahuasi town. The river never touches the town. It is actually in deep canyon called Aimana gorge when it passes below the town. There is a trail to the river with a swinging bridge over the canyon. Just below the bridge there is a difficult portage where you have to carry all equipment several hundred meters out of the canyon then walk about 1 KM and find a trail (very hard to find) that leads back down to the river in a very steep canyon...I would not want to do this with a raft or be in a raft in the Aimana gorge as it is small and very steep. Where the Aimana gorge opens up it meets the road coming down from Cotahuasi so it is easy to put in here and it is still several km above SIPIA. This section down to Sipia falls is very steep. Maybe 50 meter per kilometer average and would be very EXTREME in raft but it is possible and the trail is always close to river if there were problems.
The portage around SIPIA takes 4-5 hours per my memory. You can put -in below SIPIA below a small group of houses and then raft FLATWATER canyon that has very steep section at 57 meters per kilometer. Rafts usually continue portage and start below town of Velinga. From here is probably 60 km to Iquipe where you can take out. If you want you can continue all the way to the ocean or to where Pan AMerican highway crosses river right near coast. It is 2 more days which are sometimes hard because of wind and or slow water.
- What section is interesting on Apurimac: "Black Canyon" or "Commerical section"?
Both sections are interesting. You should do both if you do Apurimac and if you want very extreme continue to the "Acombamba Abyss" dowstream.
- What length of second and third section of Apurimac? I would guess "commerical section is 50 KM and Acombamba Abyss is more than 100km if you go all the way to San Francisco. You can make Abyss section shorter by getting out when canyon opens up at a bridge. It is very hard to find vehicles at this bridge so you need to carefully arrange transportation. See descriptions of each section in website
www.peruwhitewater.com - Where is the end of Acobamba Abyss section?
you have two options for takeout
I got out after 4 very diffiucly days at a bridge where diffiuclt whitewater finishes. It is just below where Rio Pachachaca comes into APurimac and just above where Rio Pampas comes in. From the bridge you go to Adahuaylas then Abancay then back to Cuzco.
My wife did ABYSS in a raft and it took 10 days. She continued into jungle town of San Francisco then to Ayacucho then Abancay then back to Cuzco.
- You wrote: "I would not do this section until June or after" (about Abyss). I didn`t know: June is the better time for it?"
Yes you can do in June, July, August, september and first half of October.
Before June the Abyss has too much water and in late October the rains start and river can rise very quickly. Usually November to end of April it is much too big. When went end of October and had 3 days of rain. The river grew over five times the size we stared on and was diffiuclt camping, brown water that was hard to filter and slippery rocks to portage.
PS the google map was not very good for showing the river. I am going to try to fotocopy another map and draw on it approximately where each section is. right now we rented our house to other people so are living in tents for 2 weeks. I will not be able to do anything for about 2 weeks.