By Patrick Keys
Summary: Watersheds delineated by topography and gravity are becoming obsolete. A new method of summarizing water supplies is needed. Enter the multished – defined as the surface, ground, and artificial water supplies for a particular location/region.
Note: I borrowed the theme of this post’s title from these two papers: “Stationarity is Dead: Whither Water Management” by Milly et al. 2008 and “Stationarity is Dead: Long Live Transformation” by Craig, R.K., 2010.
Introducing the concept
The watershed is rapidly becoming out-dated as a useful boundary for water supply managers. For many regions, surface water flowing downhill has not encompassed the primary water supply for many years. Gravity is now supplemented by, for example, pumps for groundwater and reverse osmosis for seawater, to provide copious additional supplies.
This post aims to define this new mode of thinking as the multished. Why? Because assessments of water scarcity and water security are based on the availability of water supplies. If significant volumes of water are omitted from these assessments of water scarcity, then regions may be wrongly labeled as “water scarce” or “water insecure”. Future posts in this multished series will explore the specifics of how the multished framework could realistically influence transboundary water security.
Lets start with a working definition. The multished is the combination of surface, ground, and piped flows that provide water to a single location (e.g. nation, city, farm). The virtual watershed* and the precipitationshed** are both omitted from the multished for the reasons specified at the bottom of this post, however they may be included as the multished definition expands.
The multished is not appropriate for management of physical processes like flooding. However, the multished is appropriate as a tool for considering water availability for municipal, industrial, energy, or even agricultural irrigation water. More importantly, the multished is an important tool for reframing negotiations in perceived zero-sum situations.
This post will introduce this topic via a city with an interesting, and rapidly changing, multished (future posts will examine the actual numbers in greater detail).
Amman, Jordan (©Pat Keys 2011. All Rights Reserved)
Amman, Jordan: water poor or water rich?
Currently, Amman experiences chronic water shortages. Why? In short, it is a high-elevation desert city, with very little surface runoff, low rainfall, a booming population, and inefficient infrastructure. This lack of adequate supply forces periodic delivery, with water flowing from the tap often only twice a month.
Amman draws limited water supplies from the Zarqa river (which is part of the larger Jordan watershed). If you look at the surface watershed of Amman, it is very small, at 129 square kilometers (sq km):
Amman watershed (©Pat Keys 2011. All Rights Reserved)
Local surface runoff from the Zarqa river is virtually unmeasureable, because the channel has turned into a sewer. Amman does not survive because of its surface watershed; Amman survives because of its multished. If all of the supplies available to Amman are considered, the region supplying water looks something like this:
Amman Multished 2012 (©Pat Keys 2011. All Rights Reserved)
And, by the year 2050, Amman’s multished could look like this…
Amman Multished 2050 (©Pat Keys 2011. All Rights Reserved)
Let me explain.
1. Water flows south through the King Abdullah Canal (KAC), from the Yarmouk River (which forms much of the border between Jordan and Syria)
King Abdullah Canal, near Adasiyah Diversion, Jordan (©Pat Keys 2011. All Rights Reserved)
2. Water flows east from Israel, through the Beit Zera diversion, which is part of Israel’s National Water Carrier (NWC) network. It is likely that any water that flows through the Beit Zera diversion is of local origin such as from the Sea of Galilee. However, given the NWC can pump water in multiple directions, it is possible that water that flows in the North of Israel is actually desalinated sea water, or water pumped from the groundwater aquifers beneath the West Bank.
Beit Zera diversion, Israel(©Pat Keys 2011. All Rights Reserved)
And if planned construction proceed as follows…
3. Water will flow north through pipes that pump water out of the Disi Aquifer (in the South of Jordan).
Pipes for transporting Disi Aquifer waters north
(©Pat Keys 2011. All Rights Reserved)
4. If the planned Red Sea to Dead Sea Canal (aka the Red Dead Canal, or RDC) is constructed, the multished of Amman will extend south to the Red Sea.