Tag: water

Energy Flows in a Desalination Plant

From a 2006 EU-funded research project called ADU-RES, here is a Sankey diagram from one of their reports (p. 24).

It features the energy flows of an autonomous desalination unit based on renewable energy. The plant (ITC’s Dessol) where they gathered the data is on the Spanish Canary Islands. “The system is conceived for small settlements (1-1500 inhabitants), since the scale/cost factor of the required investment/land restricts the capacity of production installed to 100 m³/day”.

The figures represent annual average specific energies in kWh per m³ of desalinated water (or pumped seawater?).

Sacramento/American River Sankey

From the thesis of architect and designer Gabriel Guerriero comes this beautiful Sankey diagram. Labels show quantitites but I have no information on the unit of measurement.

Gabriel writes:

“[This Sankey diagram] illustrates the measures of capacity and exchange of water in the Sacramento/American river confluence. Sankey diagrams are an essential constructive framework to analyze the breaching processes and estimate the manipulated water flows. The work is supported with calculations derived from California Department of Water Resources measurements as a means to describe where flows become broken, crosswired, appropriated, or out of tolerance. While the Sankey should hold a useful matrix to describe a section of a closed system, the Sacramento/American River measurements describe a broken system of flows in which the input of 100% on the top end results in disrupted quantities of output.”

A similar diagram for the Colorado river catchement can be seen here.

UNEP: Nigeria Freshwater Challenge

UNEP’s GRID Arendal web page that “collect[s] and catalogue[s] all graphic products that have been prepared for publications and web-sites from the last 15 years in a wide range of themes related to environment and sustainable development.” It has mainly maps and infographics. Not that many Sankey diagrams, but one I found this one interesting:

It is titled ‘Nigeria and the Freswater Challenge’, originally from a 2005 study by the Stockholm Environment Institute (SEI).

The description says:

Out of the total precipitation reaching Nigeria, it can be separated into green and blue water. Green water (79% of the precipitation) represents the fraction of rainfall that generates soil moisture and which supports terrestrial ecosystems. It is not returned to groundwater and rivers, but will eventually evaporate or transpire through plants. Blue water, on the other hand, represents the fraction (21%) of the precipitation that runs into rivers and aquifers, and that has a potential for withdrawal for societal use. Out of this, the environmental water flow is the amount of water needed to sustain ecosystem services. In the case of Nigeria, there is a huge potential to increase the withdrawal for irrigation and food production to meet current and future needs.

Flows display percentages rather than absolute values. The green water arrow representing 79% is broken down further and reveals the contributions, but only on one segment. Nice idea!

Freshwater Consumption and Distribution

The below distribution diagram (aka ‘Spagehetti diagram’) was presented on flowing data. It shows the top 10 nations in regard to freshwater consumption on the left, and the sectors where water is consumed on the right (column “Use”).

The author of the diagram is Jen Christiansen and it was originally published in a Scientific American article by Mark Fischetti.

The unit is million cubic metres per year. Only the absolute water consumption per nation is given, no values for the water consuming activities. Many of the commentators of the post pointed out that a per capita consumption of water would give a different, a “fairer” picture.

I refrain from commenting the content of the graphic. But I like the clear layout with the bands running in parallel and nicely stacked.

Water Footprint Sankey Diagram

Water footprinting has been a hot topic in the last two or three years. Water use for the production of a product, ot the water consumption of an individual, a business, or a nation are referred to as water footprint. A mere volumetric water fooprint is the simplest version, but more elaborate methods for assessing the impact on the water system have also been developed (e.g. Hoekstra, Pfister, Milà i Canals). The water footprint is also finding its way into Life Cycle Assessment with some impact assessment methods being expanded to cover the water issue.

The below is a simple Sankey diagram of embodied water. It has been published on the website of consultancy firm Ceram. Ceram conducted a water use study at the Wienerberger brick production site with a gate-to-gate perspective. So this is far from being a full water footprint, as it covers only the processes on-site, but nevertheless it is one of the first examples of a Sankey diagram being applied in that domain. [Anyone knows of other water footprint Sankey diagram examples, please let me know.]

There are no absolute values, but only percentage shares of water intake, water embodied in the product and evaporation. Only a small fraction of the water contained in the (wet) brick mass remains in the final bric (2.4%) with the larges fraction evaporating in the drying process.

Efficient Water Use in Saudi-Arabia

Consumption of water resources in arid and semi-arid areas has become an important issue over the last years. The Wafeer water conservation project is trying to raise awareness and educate people in Saudi-Arabian industry in regard to the efficient use of water. On page 21 of their Water Efficiency Manual, the following Sankey diagram can be found:

The report describes that “Sankey diagrams enable visual representation of both quantitative and qualitative characteristics of water entering and leaving different activities and therefore serve as a good communication aid.”

The above diagram does not show any unit, but presumably is meant to be in cubic metres (per year?). It shows water (blue) and waste water (grey) flows, as well as evaporation losses (red).

More water Sankey diagrams of similar style can be found on pages 19 through 23 in this workshop presentation on ‘The Importance of and Difficulties in Water Accounting’.