Water that has been collected from catchment areas

Explanation

Also, it could refers to streams and/or rivers that have been selected/reserved/classified for their waters being collected for the use of the people of Bucaramanga city.

I prefer "water collected" here, rather than "collected water", because of how it fits in with the rest of the sentence. I would translate the sentence as something like: "Water collected for the consumption of the residents/human consumption is not used for the mine." In other words, the mine has/will have its own water supply, and will not take water from the supply of potable water for the residents.
The water collected may well come from catchments in the vicinity, but the ST doesn't say this; it could be collected from roof drains, or even, as is sometimes done in Chile, among other places, from systems to harvest water from fog.