The lowest point on Earth

Hywel Griffiths and I recently attended a UK-Jordan workshop on catchment management and water security in Al Kerak, Jordan (23-25th April 2019). The workshop was supported by a grant from the British Council as part of the Newton Fund Researcher Links Programme, and was organised by Jonathan Bridge (Sheffield Hallam University, UK) and Sultan Tarawneh (Mu’tah University). The idea for the workshop originated from a long-standing collaboration between UK partners and Mu’tah University that has addressed catchment modelling and management in central Jordan. Particular focus has been on the Wadi Wala catchment that drains the western Badia Desert and the central highlands south of Amman. The upper 1743 km2 of the catchment was dammed in 2002 to provide irrigation water and function as a managed aquifer recharge (MAR) test site, with the intended benefits of improving drinking water supply to local communities. Since dam closure, however, high sedimentation rates have decreased reservoir capacity by approximately 30%, impacting its MAR performance and prompting substantial new engineering works to raise the dam wall by 15 m.

Water supply issues in the Wadi Wala catchment are emblematic of the wider water challenges in Jordan, which is widely acknowledged to be one of the most water stressed countries in the world. More than 90% of the country has a mean annual rainfall less than 200 mm, resulting in restricted surface freshwater availability and limited aquifer recharge rates, while climate change and rapid population growth – accelerated in recent years by an influx of refugees from neighbouring territories like Palestine, Syria and Iraq – have substantially increased pressures on water quantity and water quality. According to a 2015 joint UNEP and WaterLex report (see, available renewable water resources have dropped dramatically from an annual per capita share of 3600 m3 in 1946 to around 130 m3 in recent years. In addition, short-lived flash floods or longer drought episodes periodically blight different regions, leading to soil erosion, ecological disruption, infrastructural damage, and even loss of human life. So what can we do about this? How can we improve catchment management to improve water security in Jordan? Can we integrate existing and new approaches to water harvesting, wastewater re-use, soil conservation, ecological restoration, river management and so on to achieve this objective?

Hywel and myself had been invited to the workshop on the basis of our previous experience with river and wetland processes, human-environment interactions, and catchment management in drylands. Our recent contribution to the British Council workshop in Argentinian Patagonia (see was also beneficial for identifying parallels and overlap in themes covered by the workshop. A blend of early career and more established researchers from both the UK (7 others, making 9 UK participants in total) and Jordan (11 total) provided complementary expertise in hydrogeology, hydroclimatology, environmental monitoring, water harvesting techniques, irrigation, sustainable water technology, land and soil conservation, among many others.

Welcome and workshop opening at Mu’tah University

Workshop discussions at the Falcon Rock Conference Centre

The workshop was organised in three parts, covering three days. On Day 1, after a welcome from research and administrative staff at the campus of Mu’tah University (located ½ hour’s drive south of Al Kerak), the participants returned to the Falcon Rock Conference Centre for talks from the invited ‘expert mentors’, followed by breakout group discussions to identify areas of mutual interest that might form the basis for project proposals. As one of the mentors, my contribution was a ½ hour talk that provided a global perspective on rivers and wetlands in drylands. The talk highlighted, inter alia, the diversity of dryland river process and form, the role of wetlands in ecosystem service provision, and approaches to management of wetlands in drylands. A booklet from the Wetlands in Drylands Research Network entitled ‘10 Reasons why the Geomorphology of Wetlands is Important’ (see was distributed to participants, along with copies of Tooth and Ralph’s recent ‘awareness-raising’ article in ‘Geography Review’ (2019, v.32). Part of the purpose of the talk was also to contextualise rivers and wetlands in the drylands of Jordan against this wider international backdrop. What are the key characteristics of Jordan’s dryland rivers? Where are the key wetlands in Jordan’s drylands, and is there any legislative protection? What are the ecosystem services provided by these rivers and wetlands and how might the services change in future?

Building on ideas outlined by Grenfell et al. (2014, Geomorphology, v.205) and Larkin et al. (2017, Earth Surface Processes and Landforms, v.42), Tooth and Ralph’s 2019 ‘Geography Review’ article includes a diagram showing how river and wetland processes, forms and associated ecosystem services might be anticipated to undergo change as systems move along an aridity gradient. The diagram hypothesises what might happen to ecosystem services under conditions of reduced flow frequency that results from climate change (e.g. global warming that leads to lower precipitation and/or greater evapotranspiration) but also perhaps from human activities (e.g. abstraction, flow diversion).

One of the images from Tooth and Ralph’s (2019) article in Geography Review (click to enlarge)

But is it a one-way street? Can we envision scenarios whereby rivers and wetlands might move in the other direction towards a condition of greater flow frequency? One of the provocations in my talk was the potential for use of controlled wastewater discharges (i.e. treated used water, or ‘greywater’) to promote more regular flows along sections of normally ephemeral channels, with the aim of enabling within- and near-channel vegetation growth. In both rural and urban settings, this might have a range of benefits, including ecological enhancement, slowing of flow velocities, increased sediment deposition, and promotion of aquifer recharge. This might help provide some level of protection against potentially erosive flash floods and also slow sedimentation rates in downstream dams. But what might be some of the limits to such schemes? Might they just promote riparian monocultures (e.g. reedbeds) with little biodiversity gains and possibly even displacement of native riparian flora and fauna? Might fine sediment deposition under vegetated, slower flow conditions lead to change in bed surface textures, perhaps detrimentally for native fauna (e.g. macroinvertebrates) adapted to living in typically coarse-grained, open framework gravels, as well as having negative implications for rates of aquifer recharge? Might the inevitable decreases in channel cross-sectional area increase local flash hazards? And what might be the consequences of long-term sediment build-up in such vegetated reaches?

As a water scarce country, Jordan is relatively well advanced in the use of wastewater, even being cited as a ‘success story’ of regulating wastewater management in the joint UNEP/WaterLex report ( According to the report, over the last 25 years or so, the number of wastewater treatment plants has more than doubled to around 28, with more than 90% of the treated effluent being re-used in agriculture where it is sometimes mixed with rainwater. But could such treated or blended wastewater be used for the alternative purposes outlined above (e.g. ecological enhancement, flow and sediment control, aquifer recharge)? As far as I am aware there have been no studies in Jordan of the potential benefits or disbenefits – in other words, the ecosystem services or disservices – of using wastewater for these alternative purposes, and no rigorous assessments of the trade-offs involved. Farther west, on the other side of the Dead Sea, ongoing focus is on water quality and human rights issues associated with untreated wastewater discharge in Israel and the Palestinian Territories (, but one of the only studies of the potential geomorphological impacts of wastewater was published nearly two decades ago by Hassan and Egozi (2001, Earth Surface Processes and Landforms, v.26). These authors showed how nutrient-rich wastewater flow from developing urban areas caused rapid shifts from dry ephemeral channels with intermittent floods to vegetated channels with continuous flow, in some instance inducing marked decreases in cross-sectional areas. Surely, there is an opportunity to revisit some of that work and examine other aspects, including the implications for ecology and surface water-ground water interactions?

Plenty of note taking as workshop discussions continue

On Day 2, workshop participants were treated to a field trip around central Jordan. The trip was led by Esraa Tarawneh, and included visits to the Wadi Mujib and Wadi Wala dams, and the Dead Sea. Technically, the Dead Sea is an inland saline lake, with water that is nearly 10 times as salty as the ocean. Owing to diversion of inflowing water from the Jordan River that enters the Sea from the north, the level of the Sea has been falling steadily (~1 m per year over the last few decades), prompting a suite of environmental and infrastructural concerns (see

Overview of the Mujib Dam, located in the bottom of what one owner of a roadside stop has dubbed the ‘Bedouin Grand Canyon’

Overview of the engineering works being undertaken to raise the height of Wala Dam wall by an additional 15 m

A view over the Jordan Rift Valley towards the Dead Sea and the West Bank

Having descended the spectacular eastern flank of the Jordan Rift Valley to park by the side of the road that runs alongside the Sea, we all scrambled down the steeply-sloping shore sediments to the lowest land point on Earth (~430 m below global sea level). Along with the bubbling evidence of subterranean springs, and outcrops of the famous Dead Sea mud (touted by many for its supposed healing properties for skin complaints and physical ailments), there was the depressing sight of the near-ubiquitous plastic trash lines. The lowest point on Earth and surely one of humanity’s lowest points?

The famous Dead Sea mud

Plastic, plastic everywhere …

One of my earliest memories of learning about the place called the Dead Sea did not involve mention of plastics. Instead, it was a photograph in a children’s atlas from the early to mid 1970s that showed someone reading a newspaper while floating in the Dead Sea. This always intrigued me, but even then I think I vaguely understood the concept of salty water having extra buoyancy. Given the limited time available on the field trip, I decided not to investigate these properties personally (although this did mean passing up a golden photo opportunity) but luckily a random tourist was on hand to provide an ample demonstration. And an impromptu investigation of the influence of buoyancy on stone skimming proved irresistible to many on the trip, myself included.  It was hardly an example of controlled experimentation, but some of those stones did seem to skim just a few extra times off the mirror smooth surface.

A tourist in the Dead Sea. And yes, he really was floating …

Delta sediments exposed by the falling level of the Dead Sea

After returning to the vehicle, we crossed over a number of the spectacular ephemeral wadis that periodically disgorge water and sediment into the Dead Sea, sometimes with catastrophic consequences ( In the blazing afternoon sun, we also had good views of the delta sediments exposed by the falling sea level before we ascended the rift flank for the 30 km journey back to Al Kerak and its spectacular stone castle. From the lowest point on Earth and its plasticized cultural low point to what is certainly one of humanity’s cultural high points.

Approaching Al Kerak, with the castle visible on the outcrop in the upper left

Given time pressures and other priorities for the field trip, there was little opportunity for further examination or discussion of Jordan’s rivers and wetlands. On this trip and more generally throughout the workshop, wetlands in drylands remained largely out of sight and out of mind. And in the evening, one of the regular stumbling blocks to raising the profile of wetlands in drylands surfaced. Jordan has two wetlands on the Ramsar list (Azraq Oasis and Fifa Nature Reserve – see, plus undoubtedly numerous other smaller wetlands. But a Jordanian participant insisted that the Fifa Nature Reserve is not really a wetland because it only floods occasionally and isn’t always wet. No matter if it is on the Ramsar list: in their view, the absence of water year-round means that it is not really a wetland. My protests about the need for a more inclusive definition of wetlands that recognizes and celebrates those wetlands that aren’t always wet – the ephemeral, seasonal or temporary wetlands of the world – seemingly fell largely on deaf ears. Coming on the back of similar confusion at the Argentinian workshop ( – scroll down to ‘Wet Places in a Dry Land: Expanding Research into Patagonia’s Desert Rivers and Wetlands’), the growing community of wetlands in drylands researchers clearly has much work still to do.

On Day 3, the workshop again returned to the Falcon Rock Conference Centre, with activities largely revolving around breakout group discussions to identify potential projects to take forward in UK-Jordan collaborations. A range of viable projects was proposed, with most interest crystallising around projects to develop environmental databases, investigate surface water-groundwater interactions, and model climate change impacts on Jordan’s water resources.

Jon Bridge reminding us of the original aims and objectives of the workshop at the start of Day 3

Notes indicating the wealth of ideas to take forward into future activities

At this stage, and amongst this particular group of researchers, it seemed that there was not much enthusiasm for a project to investigate the potential use of controlled wastewater discharges for promoting more regular flows along sections of normally ephemeral channels, and for monitoring the impacts on river and wetland ecosystem services. To be fair, it would be a challenging project to execute, particularly given the need for controlled experimentation and ongoing monitoring over several years (minimum 3-5 years?), most likely using paired catchments. Input from specialists in Jordanian riparian ecology would also be key to the success of any such project. But at least the idea has been sown, and even if it takes some time to grow, may still be worth pursuing in future. In country so water stressed, yet also periodically blighted by disastrous flash floods, it almost seems criminal not to investigate all possible alternative uses and re-uses of the limited water supplies.


Plastics, plastics everywhere, breaking bit by bit

Saturday 10th January 2015

Here’s a really interesting story that is likely to keep on running: nautical-themed Lego pieces keep washing up on beaches in Cornwall and farther afield, nearly 18 years after the sinking of the Tokio Express container ship about 20 miles off Land’s End.  The losses included 62 containers, one of which was filled with nearly 5 million Lego pieces bound for New York.  The BBC News Magazine first covered the story back in July 2014:

An update has been published within the past few weeks, including a map of where the Lego pieces are being found (see image):

map of lego pieces

lego facebook page 2A Facebook page has even been set up to keep track of the finds (see image), some of which are likely related to the Tokio Express’s cargo, and others which may not be.  As yet, I have still to find any of the Lego pieces on Aberystwyth’s beaches but I’ll keep on looking …

This unplanned ‘experiment’ is akin to a controlled tracer exercise in geomorphology, whereby a collection of coloured pebbles are placed on a beach or in a river bed, and attempts are made to recover the pebbles at various intervals thereafter to see how far they have moved during tidal, wave or flood events. From this information, geomorphologists can learn much about the processes, patterns and rates of sediment movement in flowing water. Given that we can send manned missions to the Moon, control rovers on Mars, and even land instruments on comets more than 6 billion kilometres away (, you would think that we would know most of what we need to about these fundamental processes.  Not so.  The mechanics of sediment movement in flowing water is exceptionally complex – just think of those countless billions of sediment particles of all shapes and sizes jostling and being jostled within highly turbulent waters – and still defeats the attempts by some of the best brains to model or predict the phenomenon with any great degree of accuracy.  So even basic field experiments – planned or unplanned – still provide useful information.  As the BBC articles outline, in the case of the Lego, oceanographers and coastal geomorphologists will be able to learn much about the vagaries of oceans currents and tides, adding to our knowledge about the poorly-known watery 70% of our planet.

Although a uniquely quirky case study, the Lego story is also illustrative of the larger debate about plastic pollution in the world’s oceans.  Large areas of the oceans have become known as ‘garbage patches’, the most infamous being the huge Pacific Garbage Patch, located half way between Hawaii and California (  Were Samuel Taylor Coleridge’s ancient mariner and crew to be becalmed in this part of this ocean today, rather than complaining about a lack of drinking water, they may well have had reason to comment on all the shredded plastic bags, torn crisp packets, broken tupperware, bits of polysterene and numerous other plastic items swirling in the water column.

Regardless of whether ‘plastic soup’ is a better term than ‘garbage patch’, the problem is the same: large quantities of industrial (‘man-made’) materials are entering natural systems. Plastics, ceramics, glass, metals, bricks … the list of manufactured items goes on and on.  Ocean plastic pollution thus is illustrative of a wider debate still: namely the extent of the legacy that our industrial age will leave behind for future generations.  Some of these industrial materials will degrade over time, simply returning the compounds and elements to the Earth.  Others will be buried more or less intact in sediments on the ocean floor or along beaches.  Others will transform, perhaps fusing with natural materials to form new types of rock (e.g. so-called ‘plastiglomerate’ on Hawaiian beaches –  Others still will break down to smaller and smaller pieces but perhaps always remain in some form or other.  Physical breakdown of large plastic items to smaller and smaller pieces (collectively termed ‘microplastics’) is a particularly insidious problem, given the largely unknown implications for pollution of food chains.  Marine animals accidentally ingest some of the microplastics, which can fill the stomach and lead to death by starvation, and there is also the potential to affect higher trophic levels.  18 years after they were washed overboard and released to the ocean, some of the Lego pieces are washing up on beaches in Cornwall and farther afield in good condition.  But given 180 years, 1800 years, 18000 years or longer, into how many bits will these nearly 5 million Lego pieces fragment?