BBC reporter Paulo Cabral is travelling along Brazil's Sao Francisco river, following in the footsteps of Victorian explorer Sir Richard Burton. Each week day Paulo will be posting a diary entry on the web, and responding to a selection of your e-mails.
24 June: Sabara to Pirapora Rapids
Captain Richard Burton, September, 1867 on reaching the Pirapora (fish leap) Rapids and, at last, the Sao Francisco river wrote:
"Two men were hired to guide us in the "tender" canoe which they described as very "violenta e banzeira" - unstable and difficult. The Pirapora differs from anything that we have yet viewed; it is a superior article in quality as well as quantity. At the present season it is broken by rocky outcrops, and during the floods it has dangerous whirlpools."
Unlike Burton I didn't brave the Pirapora rapids in fragile canoe. But "unstable and difficult" would be the perfect description for the bridge spanning the river today, which I had to drive across.
A disused railway bridge has become a main crossing for cars
It is in fact an old, disused railway bridge. Trains don't run on it any more and a few wooden planks were considered enough by the locals to turn it into a bridge for cars. Not for me.
Driving along the bridge I had the constant feeling that my car would slip and fall into the waters far below, or at least get stuck in one of the many holes in the old iron and wooden structure that made such a terrifying noise as I crossed.
Just like, Burton, however, I felt a surge of emotion as my expedition had, at last, brought me to the waters of the great Sao Francisco river.
Here the river is fairly clean and allows fishing without risk of contamination and, of course, water sports. To relive Burton's experience and cross the rapids by water - in a rubber boat, not a canoe - can be arranged with a local tourist agency for about US$5.
White water rafting is still possible because another of Burton's ideas was not followed up. In his book he argued that the rocky outcrops creating the turbulence on this stretch of river should be removed to make it easier for boats to cross. How dull.
Polluting factories threaten the local environment
Nowadays it seems more reasonable to keep the river just the way it is, if not for its natural beauty and environmental value, then for its huge potential in tourism and agriculture.
Embryonic wine production has already begun in irrigated fields alongside Pirapora, an initiative already tested successfully in the city if Petrolina, further down river in the state of Pernambuco.
To top it all, my hotel room overlooks the rapids. A nice view to finish the second day of my blogging and to compensate for all the rubbish I saw in the Velhas river and the highly polluting steel industries I saw on my way here.
23 June: Belo Horizonte to Sabara
In 1867 Captain Richard Burton wrote that a bucket filled with water from the Velhas' river would contain at least half a dozen fish, plenty for a man's dinner.
Yesterday, I went to the spot where Burton started his 3000 kilometre expedition, starting along the Velhas and then onto the São Francisco river and had quite a different impression: a bucket of water could well trap one or two tiny fish, but they would be lost among the plastic bottles and bags floating on the now smelly, polluted waters.
Burton predicted that this region would one day boast a flourishing fishing industry. But mining activities, chemical industries and untreated domestic sewage from the 4 million local inhabitants have made that impossible.
Riodas Velhas: the river on which Burton began his journey
All this pollution stopped me from having a refreshing swim on a sunny and hot winter's day in the river town of Sabara. But it hasn't prevented local fishermen from catching the few and quite small fishes that still inhabit these waters.
Far from a fishing industry, they catch only enough to their feed their families. And how appetising is their catch? "Ah", said an old lady walking along the banks with her grand-daughter, "it's fine, if you dress it with a lot of lemon to remove the smell and disinfect the flesh".
Burton also wrote that from his boat he could hear fish snorting. Sadly, with less animal noise life in the water and plenty of man made sounds around, I couldn't hear them.
Luckily, I encountered a biologist from a local university who'd managed to record those fish sounds. To passing female fish these strange rumbling sounds act as a mating call. Frankly, they reminded me more of old scooters.
The lush bankside vegetation Burton described on his way from Sabara to Santa Luzia isn't there anymore, either.
In its place kilometres of grass, castor beans and a few flowering trees can only hint at what this valley could be if sustainable development, and not development at any cost, had been a concern in the last decades.