Winter is coming

After over a month of rain and favorable conditions, the Cantareira System has recovered somewhat. During the first week of April 2015, the reservoir was already at 19.3% of its reserve capacity. ANA and SABESP pointed out in December 2014, with a conservative estimate, the Cantareira System would reach 97.4 million cubic meters in April 2015. It is a little strange to estimate rainfall patterns and water volumes four months in advance for complex phenomena, and as we can see, they were completely wrong. The stored water volume has now reached 183.5 million cubic meters, and fortunately, this is a sigh of relief to Sao Paulo.

The question going into every mind is clear: we are finally back to normal?

I think we cannot know the answer to that question. For complex systems we cannot know what will happen or predict the future. What we know is that winter is coming (a recall for Games of Thrones theme alert and constant surveillance), and winter in Sao Paulo is a 6 month dry season. The other thing we know is that São Paulo water management is weak, making decisions on bad science and leaving the higher political pressure influence their actions. I rarely doubt that this combination will help solve this water crisis. What we need is less politics, less talking in media, less promises, and more serious preparation, more serious investments, more research and more stakeholder and consumer engagement to the future challenges that are to come...  

Before water collapse (in São Paulo)?

After a very dry 2014, summer rains and storms have started to hit São Paulo. During the last weeks of December and first weeks of January the Cantareira System recorded its first water level increases since April 16. The State Government and Sabesp - the water management company - could finally breathe out when reservoirs began to increase their levels of water. As rains continued non stop, national TV and newsletters even started to say that the summer drought that haunted Sao Paulo region during 2014 was not to be repeated this year. The rain and storms did not only came as a blessing, they also overflowed rivers, streams and downed threes, disrupted electrical lines, created traffic jams and so one in the metropolitan areas of São Paulo. It was a hard kick off of the new year for the São Paulo citizen. And to make things even worse, during the second half of January the rains and storms suddenly stopped. During the last two weeks it has been dry again in the Sao Paulo region. Consequently water levels of the Cantareira system has been going down, and is now at 5.1%. Some expert mean that the decision taken during the next months will be decisive to the city and the regions future.

Sabesp pumping up the technical reserve (dead volume)

Photo Daniel Meyer

So what is happening here? 

Experts such as Meehl et al. 2009 means that these wicked events are part of a new pattern of more extreme weather across the globe, shaped in part by human-induced climate change. As the climate has warmed, some types of extreme weather have become more frequent and severe in recent decades, with increases in extreme heat and drought. Heat waves are longer and hotter. Heavy rains and flooding are more frequent as well as drought In a wide swing between extremes. The extreme weather events are part of the increase in the variability of key components of Sao Paulo’s social ecological system. 

If this is an effect of Climate Change could be discussed, but these wicked warning signals are important indicators for today’s water managers in São Paulo, and I think it is clear that the city is moving into a regime shift. A regime shift is a large, sudden, and most of the time unpredictable change in a system. Once it occurs, a new regime is established that can be hard to reverse. Nevertheless, the government and the water management company Sebesp seems to follow the same old logic as during 2014, they want to prevent a regime shift at any cost. The government is now admitting for the first time there is water rationing in the state and will start implement water rotation and reduce pressure for certain city areas. And Sabesp is starting the planning of the use of a third dead volume. The third dead volume cote will correspond to 41 billion liters of water. Some say its the last reserve available.

Government agencies work under political pressure, but history has learned us that politics usually work against innovative change and for status quo. However, the short-time actions proposed by the government and Sabesp could paradoxically lead to sever consequences and even push the whole system further away from a desirable outcome. Technically, water rotation is complicated, because the lack of water in the network facilitates increase the risk of  contamination. And the use of a third dead volume will just make local ecosystem fade further, and make the water quality for citizens poorer. 

What is needed here is much more innovative action, private investment and civil society engagment, which should involve many more institutions than just the government. However, this is not happening at the scale needed, as most are still looking up at the sky for the rains.

Source: Gerald A. Meehl, Lisa Goddard, James Murphy, Ronald J. Stouffer, George Boer, Gokhan Danabasoglu, Keith Dixon, Marco A. Giorgetta, Arthur M. Greene, Ed Hawkins, Gabriele Hegerl, David Karoly, Noel Keenlyside, Masahide Kimoto, Ben Kirtman, Antonio Navarra, Roger Pulwarty, Doug Smith, Detlef Stammer, and Timothy Stockdale, 2009: Decadal Prediction. Bull. Amer. Meteor. Soc., 90, 1467–1485.