Uploaded on 2014-12-10 by mario_abb

Most building materials have a life cycle; they are gathered or manufactured, used in the construction site, spend their useful life in a building and are eventually get replaced or demolished in order to be repaired or replaced. The first and last parts of their cycles they are “flows”, and the middle part of their lives they are “stocks”. The cycle can be from a few years to decades and in some cases centuries long. Fresh produce as the one sold in fairs (bottom picture) has a shorter life cycle, it flows in as food, and flows out as solid waste. In both cases the origin of the sand and the fresh produce is the lower valleys of La Paz, called Mecapaca, most produce sold in town comes from there and is irrigated by the river Choqueyapu which ironically passes through the city, where raw sewage is dumped into it, the river's waters are not treated and go to irrigate the produce, that means there is a huge risk of spreading disease, not to mention other effects with the industrial waste dumped by factories in town. Fortunately this is not a very industrialized city, but the consequences of not treating waste water will catch up with the city. ![Stocks and Flows in the form of building materials][1] ![Fresh produce sold in a street fair][2] ![enter image description here][3] [1]: https://edxuploads.s3.amazonaws.com/14182449628703788.jpg [2]: https://edxuploads.s3.amazonaws.com/14182157715025997.jpg [3]: https://edxuploads.s3.amazonaws.com/14182459715318172.jpg