Wet places in a (normally) dry land

Sunday 24th March 2019

“Nid oes yma ddwfr croew ond sydd yn sefyll yn llyn ar ol gwlaw, yr hwn ni chefais ddim mwy o hono er pan wyf yma nag a gefais yn y Bala mewn diwrnod lawer gwaith.”  [“There is no fresh water here, except for that which stays as pools on the land after rain, that which I have not had any more of since being here than I had in one day in Bala many times.”]

So wrote William Jones in November 1865 in a letter sent from eastern Patagonia to his family in Bala, north Wales. Around six months earlier Jones had left Liverpool, England, sailing on the Mimosa into the Irish Sea and then the vast expanses of the Atlantic Ocean with around 150 other Welsh men, women and children. With financial backing from a Welsh emigration committee, and the blessing of the fledgling Argentine government, the intention was to establish a new settlement in the largely unmapped Patagonian region. In late July 1865, the emigrants finally reached the Patagonian coastline, disembarking at a location in present-day Puerto Madryn. Having endured considerable hardships during the first few months, in his letter Jones was comparing the rainfall in eastern Patagonia (mean annual rainfall about 200 mm) to the more familiar quantities in Bala (mean annual rainfall about 1000 mm). The lack of regular, extended rainfall in eastern Patagonia came as a great disappointment to the new arrivals, who had been lured from their old homeland with the promise of abundant water and plentiful pastures. But mean annual rainfall figures can be deceptive, and even arid regions can receive heavy bursts of rain every once in a while. And when these bursts come, they can be very heavy indeed, with totals that sometimes exceed 100 mm in 24 hours. In later months and years, Jones and the other Welsh settlers no doubt would have experienced some heavier rainfalls in their new homeland, as would their descendants. Indeed, in the last few years, extreme rainfall has led to widespread flooding in many parts of Patagonia, including in the still sparsely populated central regions of Chubut Province and the main population centres in the east (Puerto Madryn, Gaiman, Trelew, Rawson, Comodoro Rivadavia).

Front cover of the report on the Puerto Madryn floods of 2016

Extreme rainfall and flooding can have negative consequences, including severe erosion and sedimentation, both of which may pose threats to infrastructure and personal property. On 21st January 2016, for instance, nearly 70 mm of rain fell in Puerto Madryn in just 4 hours, leading to widespread flooding and damage to streets, houses, and industrial and commercial properties. But rainfall and flooding can also be beneficial, even essential, for they can help to replenish groundwater and reservoir supplies, and provide the lifeblood for desert ecosystems. Even in normally arid Patagonia, a variety of rivers, wetlands, shallow lakes and springs abound: wet places in a dry land. These wet places – only temporarily wet though many may be – provide a variety of ecosystem services, including water and food supply, promotion of biodiversity, and provision of recreational opportunities. In fact, in otherwise dry lands, the importance of these wet places as delivers of ecosystem service may be disproportionately important. Nonetheless, as previous blog posts have commented (e.g. see https://stephentooth.wordpress.com/2017/08/03/453/ and https://stephentooth.wordpress.com/2014/11/17/wetlands-in-drylands-how-good-is-the-service/), these ecosystem services are commonly unrecognised or underappreciated, and certainly are rarely managed for optimal or sustainable service delivery. So how do we go about changing this state of affairs?

Providing opportunities for knowledge exchange activities among different interest groups – academics, university students, policy makers, engineers, local communities, school children, and so on – is a good start. And on the back of previous work in Argentina (see https://stephentooth.wordpress.com/2014/01/06/a-potted-summary/) and other lines of research, Hywel Griffiths, myself and Gabriel Kaless from La Universidad National de La Patagonia San Juan Bosco (UNPSJB) were able to secure funding for a project through the British Council Higher Education Links Grants scheme. Entitled ‘Wet Places in a Dry Land: Securing Ecosystem Services from Patagonia’s Desert Rivers and Wetlands’, the project funding enabled Hywel and I to visit Patagonia in March 2019 to help run a series of workshops that would include many of the aforementioned interest groups. Coincidentally, and somewhat ironically, the timing of the trip also enabled us to avoid most of a spell of bad weather in Wales but instead experience first hand the capricious nature of the Patagonian weather.

Saturday 9th to Sunday 10th March

It all started well enough. The Saturday morning replacement bus/train journey from Aberystwyth to Birmingham airport was uneventful, and the Birmingham-Frankfurt and Frankfurt-Buenos Aires flights were bearable and on time. Our baggage arrived in Buenos Aires, and arrived intact. The transfer across Buenos Aires to the domestic airport was done in record time thanks to quiet Sunday morning traffic. For once, even the two hour flight south to Trelew left on time. A window seat enabled us to see first hand the aridity of the eastern Patagonian coastal regions, and we marvelled at the hardiness of the early Welsh settlers, many of whom trekked 40 miles south from their point of initial disembarkation to the lower Chubut valley in order to establish the first settlement.

Flying south to Trelew

The flight to Trelew landed on time, and again our baggage was there. Thankfully, we were at the front of the queue for car hire and despite the usual comedy routine of communications about just what was, and what was not, included in our reservation and just why our credit card details needed to taken, we left the airport swiftly. Given the various mishaps and near-disasters that had dogged various stages of travel in our previous visits to Argentina (for example, see https://stephentooth.wordpress.com/2014/01/11/a-change-of-fortune-and-a-change-of-clothes/), we also left the airport relieved.

A half hour drive west and we were at a house in Gaiman, our temporary base for the next week. Tea and cakes with the owner of our house were followed by a short sleep and shower, both essential for freshening up prior to our first meeting in person with Gabriel. First impressions confirmed what could be gleaned from the previous skype meetings and numerous email exchanges: here was someone who recognized the opportunity provided by the British Council scheme and who had also been working hard to make the workshops a success. We got straight to work with further planning for the week’s activities, and on a breezy night, continued discussions over a meal of milanesa and Patagonian beer in a local eatery.

Getting straight down to work

 

 

 

 

 

 

 

Designing baseline surveys for the workshop participants

 

Monday 11th March

Monday’s activities took place at the Trelew campus of UNPSJB, where there was a mixed audience of around 70 academics, students, representatives of government and other decision-making authorities, and other professionals. Before the start of our workshop, we had some hurried meetings with our translator (English-Spanish, Spanish-English), as we knew that she would be essential for ensuring smooth dialogue. Thankfully, email exchanges beforehand had answered most of her and our questions, and we were ready to go.

Crossing fingers and gritting teeth: nervous anticipation by Hywel and our translator ahead of the opening presentation

Pre-presentation activities for workshop participants

Cramming notes ahead ahead of presenting

In a room that seemed to get hotter with every minute thanks to the healthy attendance and the sun that blazed through the single-paned windows onto the blinds, the morning theme focused on flood risk and perceptions. Opening presentations were given by Hywel and myself on flood memories and adaptations among the early Welsh settlers and their descendants, and were followed by presentations by local Argentine researchers on the common mismatch between technical assessments and social perceptions of urban flood and mudflow hazards.

Paula Ferrari talks about past floods in Trelew

Gabriel chairs a plenary discussion

The afternoon theme focused on desert and semi-desert rivers and wetlands and involved a presentation by myself and Hywel that provided a global perspective on these wet places in a dry land, and one by Gabriel and colleagues on the measurement, recording and impacts of extreme rainfall and flood events. Following each set of presentations, there was lots of engaged, rapid discussion in Spanish among the audience, both in the smaller breakout group activities and the ensuing plenary discussions. Plenary discussions were chaired by Gabriel, with the translator helping Hywel and I to keep track of the key points, and it was clear that there was plenty of interest in the Welsh settlement history and the unique historical perspective that this brings to the analysis of environmental change in the Patagonian environment. Furthermore, despite some confusion over the very concept of a wetland in a dryland – a confusion that Gabriel later admitted might have been due to the choice of word ‘humedal’ as a translation of wetland – there was obvious interest in developing more of a Patagonian perspective on desert and semi-desert wetlands.

What do you mean by ‘a wetland in a dryland’? Some confusion is evident

The source of the confusion

Reflection on the first day’s activities

 

Tuesday 12th March

Tuesday’s activities took place at El Centro Nacional Patagónico (CONICET-CENPAT) in Puerto Madryn, located about 1.5 hours drive from Gaiman. The location had been chosen specifically to ensure wider engagement with academics and researchers based in the city, and around 25 people were present.

The format was essentially a repeat of the previous day’s presentations, activities and discussions, but the smaller, more specialist audience helped to bring a more technical, research-led perspective on discussions. While many similar issues were aired – particularly the complex definition of wetlands in drylands – others were given more prominence than on the previous day, such as the importance and challenges of communicating the science of rivers, wetlands and ecosystem services to different interest groups, and the potential strategies for doing so.

Taking notes during a plenary discussion session

More food for thought emerging from the discussions

El Centro Nacional Patagónico is located just a short distance from where the first contingent of Welsh emigrants set foot on the Patagonian shore. On a warm and sunny yet breezy day, Hywel and I took advantage of the generous lunch break to walk to the shore, where we tried to imagine the first thoughts of those emigrants as they contemplated their new home. At the end of the day, in the setting sun and enveloping dusk, we also did a quick tour of the various monuments to the Welsh settlers that are dotted along the Puerto Madryn seafront, some of which rightfully acknowledge the role played by the native peoples in helping the fledgling settlements. And thanks to CENPAT’s generosity, we were then treated to a meal in a local seafood restaurant. In setting out for the 1.5 hour drive back to Gaiman, we ran into the inevitable late night police roadblock on the outskirts of town, but luckily our immaculate paperwork and knowledge of the Welsh footballer Gareth Bale smoothed the potentially awkward conversation, and the delay was only minor.

The south end of Puerto Madryn seafront, located near to where the first contingent of Welsh emigrants disembarked 154 years ago

 

Wednesday 13th March

Reflections on the second day’s activities and a look forward to day 3

Wednesday’s activities again took place at the Trelew campus of UNPSJB. Again, there was a mixed audience of about 70 people but today the room was much cooler thanks to cloud cover and periodic burst of rains. While the coolness was welcome, the rain provided a portent of things to come. This day’s theme was different yet complementary to those on previous days, focusing more explicitly on ecosystem services. Presentations were given by CENPAT and UNPSJB researchers on aspects of ecosystem service delivery and landscape restoration approaches in the lower Chubut River valley, while a presentation by Hywel and myself highlighted how geotourism can tap the often underappreciated cultural ecosystem services.

A view from the back of the room as day 3 gets underway

Just before our presentation, we had been whisked away to a noisy corridor to give an interview to a local TV network about the workshops and its intentions. While the interview went well, it was brief, and plans were made for a more extended interview the next day at the network’s station. After our presentation, breakout group activities and a plenary discussion took place. As with the previous days’ discussions, I found it hard to follow everything that was said: my understanding of rapidly spoken Spanish is just not up to the task. But I had quickly realised that this was not the point anyway. Instead, it mattered more that discussions had been generated amongst a cross section of people who live and work in Patagonia, and who need to be engaged with the issues. And even with a partial understanding, and the translator’s summary of the main points, we got the feeling that the relatively unknown topic of geotourism had created a genuine buzz amongst many of those present, with positive feedback being given to our presentation and several useful contacts for potential future projects being made.

Andrés Malnero gives a colourful presentation

 

Hywel presenting some of Sioned Llywelyn’s PhD findings: can approaches to geotourism developed in Wales be applied in the Patagonian context?

Wednesday lunchtime and afternoon provided a chance to start fleshing out the details of the numerous possible future collaborative projects, identification of which is a key requirement of the British Council scheme. Luckily, there was no shortage of enthusiasm, more a need for prioritisation and logical sequencing of projects, especially bearing in mind the necessity for additional funding.

A working lunch at the Touring Club.  One side of the table …

… and the other.

Hywel opens his presentation to the Welsh Association of Trelew San David

Wednesday evening involved a presentation by Hywel (in Welsh, with Spanish translation) to the Welsh Association of Trelew San David. A tremendous electrical storm that was breaking in the valley around the time of the presentation had kept a few potential attendees away but added a tinge of excitement to proceedings. The presentation provided lots of scope for discussion among the local Welsh-speaking community, some of whom are descended from the early settlers, particularly as we were able to report a summary of our findings from our previous project undertaken in early 2014.

Heavy rain creates problems in some of Trelew’s bars and restaurants

After the presentation had finished, we heeded reports of a power cut in Gaiman that had resulted from the storm. As such, we stayed in Trelew with some people from the presentation, enjoying food and a drink in a restaurant despite the continuous heavy rain that ensured a steady drip of water through parts of the roof.

We returned to Gaiman late in the evening, finding in the still incessant rain that the electricity was still out in much of the town.

Thursday 14th March

In the morning, still there was no power and the rain continued. We headed into Trelew for a meeting with Gabriel who would take us to the intended interview at the TV station, but a power cut there had meant that this had to be cancelled. This news came too late for our translator who had travelled all the way down from Puerto Madryn, but we made good use of a meeting in a local café with a review of the previous day’s activities and plans for future projects.

Heading into the desert on a very wet day

The rain had raised some uncertainty over whether our initial plans for a trip to stream gauging sites located in the Patagonian desert should go ahead. Heavy rain can make the dirt tracks in the desert tough going or impassable. But with the rain seemingly easing, we decided to go for it. Travelling up the north side of the lower Chubut valley by tarred road, then crossing the irrigated floodplain and river onto the dirt tracks on the south side of the valley, after about an hour we found ourselves passing through increasingly more rugged terrain. Some very heavy bursts of rain continued, but having got this far, we were not going to be deterred.

A flow gauge but with nothing to measure

Our first visit was to a stream gauging station located along one of the numerous normally dry creeks that dissects the desert margins of the valley on its course to the permanently-flowing Chubut River. Since starting my PhD studies in Australia just over 26 ago, I have spent many hours wandering up and down similar creeks – technically known as ephemeral rivers – in various parts of the world, yet had never witnessed any actually flowing. And I’ll admit that I was a little disappointed when even the heavy rain seemed to do no more than simply dampen the sandy bed. Just what sort of rainfall does it take to get these creeks to actually carry flow?

A view across a very wet desert

But as we drove around other parts of the desert, it became obvious that on the usually sun-baked surfaces above the rivers, water was starting to pool or be shed downslope, while smaller creeks were starting to carry flow. We walked across rugged hillsides to larger creeks, many of which were also now starting to flow, and flow more forcefully. We were wet through but hey, ‘merece la pena’ … it was worthwhile. Finally, I would have my own photos and videos of a water-activated desert to use in future presentations. But after a few hours, we were all getting a bit cold, and it was time to head back to town for an evening parilla (barbeque).

A desert pavement, shedding water in the rain just like one constructed of concrete

Walking across the hillside to a creek in flood

A desert creek roaring ever more loudly

A flow gauge, now with something to measure

The desert had other ideas. As we returned to cross the previously dry creek with its gauging station, we found that a raging torrent now blocked our exit. With a depth of around 1 m and an estimated flow speed of about 2 m per second, this was far too dangerous to cross by vehicle, and we had no choice but to wait it out and hope that the water level would drop sufficiently in a couple of hours.

Our route out of the desert is blocked

We made good use of the delayed departure, visiting other flooded creeks to capture more footage. But as the day wore on, the rain continued in bursts, and the water level did not seem to be receding very fast, concern set in. Serious thoughts were being given to spending a night in a nearby house that formed part of a kaolin plant set in the desert, but with just what food provisions I didn’t dare ask. I was more concerned about the almost unthinkable possibilities of not being able to exit the desert even the next day and then missing our flight back to Buenos Aires. “Cuando en el desierto patagónico los arroyos braman” (“When the creeks roar in the Patagonian Desert”). So goes the title of an article written by Gabriel and colleagues. The creeks were roaring for sure, and I was doing some inner roaring of my own. Luckily, just when all seemed lost, at dusk the owner of the kaolin plant took us to the creek to assess the situation. It was still flowing, albeit slightly less deeply and swiftly than a hour or two beforehand. But it was enough to convince the plant owner that it was safe to cross, and without much warning he did just that, barreling through the turbid current and soft sandy bed to the drier, firmer gravel on the far side.

With some trepidation, we followed, and also crossed safely. A slow journey at dusk then ensued along the rest of the dirt road, which now supported significant pools of water. But after dark, we finally reached the relative safety of the tarred road that runs along the more central and northern part of the lower Chubut valley, and we all breathed a collective sigh of relief.

Eventually, we made back to Trelew and the parilla, tired but with a tale that will live long in the memory.

Friday 15th March

The Chubut River in Gaiman with its cargo of desert sediment

After breakfast, we packed and left Gaiman, heading into Trelew for a meeting at the university with Gabriel and others to discuss future project proposals and British Council reporting requirements. The rain was easing but in Gaiman the Chubut River had turned the colour of milky hot chocolate thanks to the sediment-laden runoff from the desert creeks that join the river farther upvalley, while in Trelew, large puddles occupied many of the side roads. Reports were also being received of heavy rain and flooding in Puerto Madryn. While not on the scale of some previous rural and urban flood events that have impacted on this part of eastern Patagonia in recent years, the potential for the severe disruption that can result from rainfall and river flooding was abundantly clear.

A flooded side road in Trelew

A whiteboard full of potential project ideas …

The discussions about future project proposals and reporting requirements were easy. With no shortage of ideas, instead the difficulty was scribbling every idea into the available whiteboard space. We would have plenty to contemplate during our return trip and in the weeks and months to come.

… but which ones to prioritise?

 

Remainder of Friday 15th, and Saturday 16th to Sunday 17th March

As for the return trip …. one quick stop at a lifesize model of the world’s largest dinosaur (a 42 m long, 12 m tall titanosaur sauropod, located near Trelew airport) before we returned our hire car. One uneventful mid evening flight to Buenos Aires. One night in a very noisy downtown Buenos Aires hotel. One Sunday morning walk around the decaying streets of San Nicolás, Monserrat and San Telmo. As for the very turbulent, cramped flights to Frankfurt and Birmingham, the less said the better. The same goes for the expectedly awful train/replacement bus journey from the Birmingham Airport to a location close to Aberystwyth (note the emphasis on close to, but not actually to, Aberystwyth, thanks to rail engineering works and the seemingly little thought given to those who actually needed to reach the end of the line). But thanks to the generosity of a local friend who arranged to pick us up late at night, both Hywel and I got back to our respective homes just before midnight.

Postscript

People sometimes question why academics at a Welsh university are doing geographical research in Argentine Patagonia. We typically counter by saying that despite the great distance between the two regions, we share some common history and have enduring cultural ties. But also relevant is that despite considerable differences in average climatic conditions, we also face many common environmental challenges, including dealing with extremes of rainfall, flood and drought, and ensuring wise use of the ecosystem services provided by rivers and wetlands. And to neatly illustrate this point, as we were leaving rain-soaked, partially flooded eastern Patagonia and making our journey back to Wales, we learnt of heavy rain in Bala and many other parts of Wales. According to Natural Resources Wales, Capel Curig, located only about 30 miles by road from Bala, had received more than half a month’s worth of rain (136.6 mm) in 24 hours.

Screen shot of a BBC website highlighting heavy rainfall and flooding in Wales

The Conwy, the Dyfi, the Wye and many other rivers were in flood, with flood warnings issued for several towns (including Bala), while landslides had occurred in some steeper terrain, leading to severe disruption to rail and road transport. Meanwhile in parts of eastern Patagonia, the bad weather had also continued: we later heard that since Friday schools in parts of Puerto Madryn, Trelew and Rawson had been closed and many people had not had potable water in their houses.

Under a warming, more variable climate, the overwhelming scientific consensus is that such weather extremes are likely to be more common in the years ahead, a situation that inevitably will influence the nature and quality of ecosystem service delivery and regularly test community and wider societal resilience. Significant challenges will be faced, to put it mildly. But through schemes that promote knowledge exchange between academics and other interested parties, such as those funded by the British Council, we are more likely to be able to identify strategies and solutions that will help us rise to such challenges.

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Extreme events, restricted coverage

Saturday 13th January 2018

After the end of a year that has been declared to be the one of the warmest on record (see http://www.bbc.co.uk/news/science-environment-41859288 and http://www.noaa.gov/news/2017-was-3rd-warmest-year-on-record-for-us), a year marked by yet another series of extremes events (e.g. floods, droughts, hurricanes, wildfires), you might think that 2018 would be relatively quiet in comparison. Not a bit of it … at least not based on the first two weeks of the new year. January 2018 has started in ferocious mood, with a ‘bomb cyclone’ (technically ‘explosive cyclogenesis’) in North America, extreme heat in Sydney, coastal storms in Britain, and heavy rain, flash floods and mudslides in California. It’s unclear whether this mood will last through 2018 (e.g. see an article in The Conversation) but the signs are not positive.

Much of the mainstream media coverage of these extreme events understandably focuses on the ‘disaster’ element: infrastructural damage, travel disruption, and the human tragedies, lucky escapes or heroics. But is there room for just a little more science? Having skimmed the media coverage of the later two events – British coastal storms and Californian mudslides – two things strike me.

The first is an observation that despite abundant opportunity to use terms such as ‘geomorphology’, ‘geoscience’. ‘earth surface processes’, ‘topographic change’ or ‘landscape change’, rarely is this done, even alongside the potentially suitable graphics that accompany such articles. Surely, readers of the BBC and other quality news outlets can handle a smattering of these terms as part of a wider, human-focused story?

The second, and more important, is the underlying tone of surprise that seems to accompany the reporting of the sediment movement that may be associated with extreme hydrometeorological events. Large amounts of sand are moved during extreme coastal storms, leading to chopping back of the beach face, creation of ‘sand cliffs’, and shifting of the course of beach-traversing rivers. Sediment-laden flows are generated by heavy rains on steep, weathered, burnt, hillsides. Isn’t all this to be expected? You can forgive British readers for not being so familiar with flash floods and mudslides that sometimes follow intense fires. But anyone who has visited the British coastline on a regular basis should know that in the absence of hard engineering works, sandy beaches are highly dynamic. Extreme wave events typically accomplish substantial erosion, with large volumes of sand commonly moving offshore, but ensuing large, moderate and small wave events will gradually move this sand back onshore to ensure beach rebuilding. Case studies from Ireland have shown how sandy beaches can suddenly disappear and then re-appear months, years, or even decades later (http://theconversation.com/why-beaches-lose-their-sand-and-then-suddenly-reappear-77503). Much depends on the sequence of different size wave events, and there are legitimate concerns over the apparent greater frequency of the extreme events that may be disrupting the historically roughly balanced rhythm of offshore-onshore sand movement and initiating a longer term trend towards increasing erosion. But even if this is the case, there are opportunities as well as threats. Previous events in places like eastern Ireland, west Wales and the English coastline have shown how mobile beach sand can lead to serendipitous discoveries, including new exposures of mid Holocene submerged forests, Bronze Age deer antlers and wattle walkways, as well as numerous other archaeological finds. For flanking coastal wind-blown sand dunes, erosion and continual sand mobility – perhaps during extreme wave or wind events – in many cases may actually be essential for maintenance of biodiversity, as shown by case studies of dunes along the south and west Wales coastlines (https://stephentooth.wordpress.com/2015/10/29/10-reasons-why-10-rheswm-pam-8/).

In other words, extreme events provide both threats but also opportunities for renewal, discovery and change, with potential for geotourism, ecotourism and archaeologically-based tourism initiatives. Admittedly, in the aftermath of events like the Californian mudslides that have led to serious infrastructural damage and loss of life, it’s hard to see any positives. But in other cases, can the opportunities provide a counternarrative to the prevailing tone of pessimism or surprise commonly associated with reporting on extremes? This idea of ‘erosion as attraction’ has been raised by others (e.g. Matless, D. 2016. Climate change stories and the Anthroposcenic. Nature Climate Change, 6: 118-119, doi: 10.1038/nclimate2862) but why does this alternative perspective rarely feature in the mainstream media coverage of extreme events?

The duality of wetlands in drylands: deluge and drought

Thursday 3rd August 2017

The 2nd Wetlands in Drylands (WiDs) meeting took place at Macquarie University in Sydney, Australia, between 24-26th July 2017.  Organised by Tim Ralph, the meeting involved presentations and breakout group discussions, and was followed by a four-day excursion to the Macquarie Marshes in inland central New South Wales.  Following on from the inaugural WiDs meeting held near Parys, South Africa in November 2014, a meeting that led to formation to formation of the Wetlands in Drylands Research Network (see http://wetlandsindrylands.net/), this post is an attempt to cast a perspective over the activities.  The activities provided an opportunity not only to assess progress in wetlands in drylands research since the Parys meeting, but also to place these activities against the backdrop of more than two decades of research and management in the Macquarie Marshes in particular.

1 WIDs Day 1 intro

Tim Ralph giving the opening address at the WiDs 2017 meeting at Macquarie University (Photo: Will Farebrother)

A day-by-day outline of activities at Macquarie University is provided elsewhere (see http://wetlandsindrylands.net/latest-posts/).  Stepping back a little, it is noteworthy that compared to the Parys meeting, which was specifically for 16 UK and South African wetland researchers alone (this was a stipulation of the catalysing funding scheme), the Macquarie meeting was larger (~50 attendees) and more diverse.  A common lament at the Parys meeting was the absence of involvement from other people whose social and professional lives revolve around wetlands in drylands (e.g. representatives of local community groups, subsistence and commercial farmers, wetland managers and policy makers).  Most wetlands in drylands are living and working landscapes, such that the relatively new term ‘social-ecological system’ can be readily applied.  While blue-skies wetland research remains important, in many instances this can benefit from, and dovetail with, additional perspectives.  But thanks to Tim’s sterling organisational efforts, the Macquarie meeting and the associated excursion was blessed with inputs not only from wetland researchers spread across four continents but also from additional constituencies: wetland managers and policy makers, wetland landholders, and – importantly – representatives of the Traditional Owners of the Macquarie Marshes (the Aboriginal Wayilwan nation).  As befitted the meeting theme of ‘Dynamic Landscapes’, specialist sessions focused on hydrogeomorphological, biogeochemical and ecological dynamics, and the resilience and sensitivity of wetlands in drylands, but later sessions were set aside to consider the interactions between science and management, and indigenous knowledge and management.

As a consequence of this diverse involvement and structure, discussions following presentations and in the breakout groups were considerably enriched, with particular attention focusing on how best to build and maintain strong relationships between scientists, managers and other stakeholders to address the many challenges facing wetlands in drylands.  What are the main barriers to, and opportunities for, communication and sharing of wetland knowledge and insights?  How best can wetland researchers translate findings into forms that can be assimilated by wetland managers?  To what extent should management concerns help to shape wetland research priorities?  Can environmental water flow releases from reservoirs work in synergy with ‘cultural flows’ to enable maintenance of local customs associated with water (e.g. fishing)?  And how can cultural perspectives on wetlands – oral histories and the like – be dovetailed with scientific perspectives?

The excursion – dubbed the ‘Macquarie Marshes Research Outreach Event’ – provided an opportunity to continue such discussions in a specific field setting.  This is one of Australia’s iconic wetlands in drylands, known especially for its diverse aquatic and semi-aquatic habitats that occur amidst the otherwise dusty, semi-arid plains of inland New South Wales.  Internationally, these wetlands are best known for their periodic profusion of waterbird populations, which in large part led to their 1986 listing as a Ramsar Wetland of International Importance (https://rsis.ramsar.org/ris/337).  Fed largely by seasonal rainfall gathered in its southern headwaters, historically the Macquarie River flowed freely northwest and north past towns such as Wellington, Dubbo and Warren, eventually disgorging its water and sediment amongst a confusing tangle of active and abandoned channels, marshlands, swamplands, floodplains, woodlands and lagoons.  In particularly wet years, the extent of flood inundation could expand to around 3000 km2 (300 000 ha) – an area roughly fifty-five times the size of Sydney Harbour or 1% of the total area of the United Kingdom – only to shrink back to much smaller areas of more-or-less permanently wet, ‘core wetlands’ during drier years.  Such a wetting-and-drying dynamic is the natural norm in inland Australia’s highly variable climate, and is associated with a well-adapted boom-and-bust ecology.  The local Aboriginal peoples would have known these rhythms well, adapting their cultural practices accordingly.  But European explorers and colonists took far longer to appreciate them.  In 1818, John Oxley arrived at the edge of the marshes in flood and turned around, concluding that he had arrived at an inland sea.  A decade later, Charles Sturt came during a drought and found largely dry floodplains, albeit ones dotted with small waterbodies, concluding instead that only in very heavy rains could the marshes and adjacent lands be inundated.  Even with the benefit of nearly 200 years of collective hindsight, fleeting visits still colour many people’s perceptions of the value of wetlands in drylands.  The marshes offer a very different personal experience in a wet year compared to a dry year, but both are needed for a fuller comprehension of the system’s workings.

2 middle Macquarie River

Winter low flows in the middle Macquarie River between Dubbo and Warren (Photo: Stephen Tooth)

3 Marshes wet & dry 2008-2010

The southern part of the Macquarie Marshes Nature Reserve in times of drought (late September 2008) and flood (late November 2010) (Photos: Tim Ralph)

And like many other wetlands in drylands around the globe, the absence of this longer-term perspective has been partly culpable for a steady decline in the health of the Macquarie Marshes, whether this be measured in terms of tree deaths, reduced diversity of vegetation and fish communities, or declining waterbird numbers.  Upstream dam construction and associated flow regulation, urban and agricultural flow extractions, and creeping encroachment from irrigated lands have all taken their toll on the marshes.  To this toxic mix, add complications from river and floodplain engineering schemes, marsh-dissecting roadworks, and greater flow variability resulting from climate change, and their declining health should come as no surprise.  In short, apart from a few areas of the marshes where inundation is now more-or-less permanent (and somewhat ironically can result in tree deaths and adverse soil geochemical changes), in many other parts, flooding events are now less frequent and less extensive, while desiccation events are becoming more frequent and more severe.

4b swamp stomp compiled

Swamp stomping in Buckiinguy Swamp (Photos: Stephen Tooth)

4a Willancorah swamp

Willancorah Swamp in the southern marshes (Photo: Stephen Tooth)

Roughly 90% of the Macquarie Marshes is now in private ownership, with the remaining 10% in protected areas, most notably the Ramsar-listed Macquarie Marshes Nature Reserve, but even these sorts of designations have not provided immunity from the overall health decline.  The two main portions of the reserve (southern and northern) are not accessible to local people or visitors from farther afield, so many of the deleterious changes that have taken place within the southern portion especially – desiccation, tree deaths, channel erosion, and so forth – have gone largely unnoticed.  In itself, this lack of public awareness is part of the problem.  In a 1992 commentary in the National Parks Journal, Bill Johnson (a former ranger with the NSW National Parks and Wildlife Service) argued that that while there was a need to halt many of the processes contributing to their decline and to begin restoration, the long-term viability of the Marshes is “totally dependent upon the involvement of the wider community in the management of the wetlands and the Macquarie River”.  An Australian Geographic article from March 1996 provided a snapshot of conditions in the marshes, highlighting the rich birdlife in particular, but not shying away from reporting some of the negative ecological changes, including tree deaths, waterbird declines, and the spread of invasive species such as the European carp and feral pigs.  It also sampled a wide range of local community views on the management of the marshes, including a quote from a now-departed local resident: “If people can’t visit the marshes, they won’t care about them”.  In this respect too, personal experience is vital for influencing perceptions of the value of wetlands in drylands.

5 dry marshes nature reserve

The entrance to the dominantly dry southern portion of the Nature Reserve (Photo: Stephen Tooth)

5b kangaroos

Mobs of roos within the Nature Reserve (Photo: Stephen Tooth)

Johnson’s commentary and the Australian Geographic article both focused on the key issue facing the marshes, namely the diverse views regarding the provision of water for urban, agricultural, environmental, and cultural purposes.  In a 1998 article in the Australian Geographer, Philippa Brock (then-time member of the Macquarie Marshes Catchment Committee) provided an overview of the declining physical status of the marshes and the evermore complex water allocation and distribution framework that was trying to balance the competing demands.  She highlighted the need for scientists and managers to work together to develop expertise in addressing natural and artificial changes in the marshes, concluding that the best that we could hope to achieve was: “… management of this unique ecosystem in a manner as close as possible to a ‘natural state’.  In an already regulated river system … this may require some degree of intervention and ‘active management’.”

These articles were published during the 1990s when La Niña conditions were still generating moderate rainfall and flooding.  In retrospect, this decade might be referred to as the last heyday of the marshes.  Ecological health worsened dramatically during the ‘millennium drought’ (c. 2001-2010), but has improved slightly in recent years, as a new La Niña phase has led to the return of moderate flows.  Intense competition for water has remained, however, and the policies and practices for water allocation and distribution have undergone further evolution.  So two decades or more later, where do we stand against the views and opinions expressed by an earlier generation of marshes managers and residents?  Has any progress been made against the calls for greater community involvement, and for closer working between scientists and managers?  Has scientific research provide any traction with the issues of negative ecological change?  Have channel and floodplain restoration efforts succeeded or failed?  Are there improved policies to balance the competing demands for water?  And how have local community perspectives fared within the negotiating rooms?

The excursion to the Marshes provided an opportunity for myself and others to ponder these sorts of issues.  And it’s mixed news.  Thanks especially to the work of Tim Ralph, his academic colleagues and students, our knowledge of the geomorphology, sedimentology, and environmental history of the Marshes has improved considerably.  Along with important contributions from other research groups, the links between landforms, earth surface processes, and ecological functioning in the marshes are now much better known, albeit still incomplete.  There is, for instance, much greater cognisance of the intrinsic dynamism of these ‘wandering wetlands’ and how lateral channel shifts, erosion and sedimentation can lead naturally to changes in wetland location and extent, regardless of conservation boundaries (http://www.environment.nsw.gov.au/news/keeping-watch-over-a-wandering-wetland).  Suggestions that the degraded and drying southern portion of the Nature Reserve should be abandoned in favour of focusing efforts on the wetter northern portion can be rebuffed with the argument that a longer term perspective is needed: wait for the next lateral channel shift, keep patient during the drought, and wetter conditions will likely return.

6a chewing the fat 1

Chewing the fat at Willie Retreat (Photo: Stephen Tooth)

Some of these insights have been implemented in management policies and practices.  Some attempts at restoration of parts of the marshes have failed, even threatening the Ramsar status of the Nature Reserve (see http://www.environment.nsw.gov.au/wetlands/20130104mmrsart32.htm), but lessons have been learned and are being incorporated into management practices (e.g. improving the design of channel-spanning weirs).  Some private landowners are fully on board with attempts to better understanding the landscapes and ecosystems of the marshes, and readily facilitate scientific research efforts.  While the Nature Reserve is still not publically accessible (a decision that seems to be based mainly on attempts to exclude unwelcome visitors such as illegal pig hunters), local community (including Wayilwan) perspectives are now given greater prominence in round-table discussions about the management plans for the reserve and the marshes more widely.

6b chewing the fat 2

Discussing the long history of Aboriginal occupation and use of the marshes.  A degraded mound (lower right) provides evidence of a ceremonial site alongside the old Macquarie River (Photo: Stephen Tooth)

Progress on other issues remains unclear, at least to me.  In a short visit of only two full days, it was impossible for me to get my head around the intricacies of the current marshes water allocation and distribution system, let alone its long and complex history.  Each year, many tens or hundreds of thousands of megalitres of water are released from the Burrendong Dam, but this is divided between environmental flows, irrigation flows, by pass flows and so on …. it’s a complex terminology with complex definitions that is coupled with complex demands competing in a complex social web.  All that is best left for others to elaborate on (see http://www.environment.nsw.gov.au/environmentalwater/macquarie-profile.htm).  Similarly, local issues of environmental management and social justice can’t be debated and resolved in a few quick conversations: for instance, just when do we intervene – or not intervene – in natural process such as channel abandonment and flow diversion, and how do we compensate those downstream users who may be deprived of water, or inconvenienced by changing flood patterns?  But the main point is that rarely can science and management be divorced from social context and consequence.

6c chewing the fat 3

Debating the options for channel and floodplain wetland restoration in the southern portion of the Nature Reserve (Photo: Stephen Tooth)

Even if answers can’t be provided immediately, approaches to a search for solutions can be outlined, at least in theory: namely, the need to facilitate ongoing communication, dialogue, and exchange of ideas between different scientists, managers, local community groups, and other stakeholders.  There is no simple recipe for doing so, but discussions at the meeting and on the excursion provided anecdotes and case studies to highlight at least some best practice principles.  Building trusting relationships by taking the time to listen to people’s views, engaging with environmental education projects in local communities, and organising open field visits such as the Macquarie Marshes Research Outreach Event …. none of these are magic bullets, but they can help lay the foundations for moving forward.  And in the Macquarie Marshes, many of the foundations are there already, not least because there seems to be sufficient shared concern about the future of the marshes for people to be open to ongoing communication.

Maintaining and building on these foundations is a constant challenge.  As discussions in the field, around the campfire, and on the bus home unfolded, it struck me that people within living and working wetland social-ecological systems enter and depart the scene, much like many of the waterbirds come and go with floods and droughts.  Like stately River Red Gums that line the Macquarie River banks, some individuals, families, social groupings and institutions provide continuity across the decades, persisting through cycles of flood and drought and withstanding the changing water allocation and environmental management frameworks.  But like Bill Johnson and others that frequented the Macquarie Marshes in the 1980s and 1990s, many move on or pass away.  Other people take their place, but with each entry and departure, knowledge and wisdom has to be re-learned and trusting, working and social relationships have to be rebuilt.

Of course, such issues are not unique to the Macquarie Marshes.  Institutional policies and practices can provide some sort of inherited memory and learning to enable ongoing progress, regardless of individual involvements.  In environmental management circles, ‘adaptive management’ is now the mantra.  Adaptive management practices acknowledge that despite uncertainty, decisions must be made and actions implemented, but emphasise learning from the outcomes to inform future decision making.  The Macquarie Marshes has its own adaptive management plan (written by Bill Johnson in a new role – see http://www.environment.nsw.gov.au/resources/environmentalwater/100224-aemp-macquarie-marsh.pdf), something that may well be essential in managing for a future that seems to be getting just a little more uncertain with each passing year.  Let’s hope that in two decades or more, a retrospective similar to the one attempted here will provide positive rather than negative commentary on the state of the Macquarie Marshes social-ecological system.

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Footnote: I gratefully acknowledge sponsorship from the NSW Office of Environment and Heritage (OEH) and Macquarie University for the Macquarie Marshes Research Outreach Event.  I also thank OEH staff, local landholders and representatives of the local community for their support and participation.  I thank Tim Ralph in particular for additional discussions and suggestions.  While informed by discussions on the excursion, the views expressed in this post are of course my own.

10 Reasons Why …. 10 Rheswm Pam …. : 10

Tuesday 22nd December 2015

Blog post 10 of 10 about the geomorphology of Wales. Click on images to view larger version in a separate window. Parallel blog in Welsh at http://hywelgriffiths.blogspot.co.uk/

Reason 10. Successful environmental management needs geomorphological knowledge. Geomorphology can provide a key input to environmental management, including landscape conservation, ecosystem conservation and restoration, heritage conservation and carbon landscaping.

Sgwd GwladusOn account of spectacular natural and cultural landscapes, large areas of Wales have protected status. Collectively, the three National Parks in Wales – Snowdonia, Pembrokeshire Coast and Brecon Beacons – protect an impressive 20% of the country, including landscapes, habitats, and heritage sites (http://www.visitwales.com/explore/national-parks). The National Parks are complemented by other areas with varying levels of protection (e.g. Geoparks, a Biosphere Reserve, Sites of Special Scientific Interest, Special Areas of Conservation, National Nature Reserves) some of which overlap in space. For example, the Fforest Fawr Geopark (established 2005) is contained with the western part of the Brecon Beacons National Park, with some key objectives being to conserve and enhance the geological and geomorphological heritage, including by developing the area’s potential as an outdoor classroom and geotourism destination (http://www.fforestfawrgeopark.org.uk/). A complex history of tectonic and climatic changes have acted upon the varied lithologies in the area to form a diversity of landscapes and landforms (Reason 2), many of which form drawcards for tourists. The area around Pontneddfechan, Powys, is a case in point, as it is renowned for its high number of publically-accessible waterfalls that have developed on sedimentary strata, such as Sgwd Gwladus (Photo: Stephen Tooth). Although underutilised at present, geomorphology can play a key role in enhancing the tourist experience by providing information about the origins, development and significance of such landforms, and also can contribute to the development of sustainable management strategies for these popular but protected areas.

In National Nature Reserves, geomorphological processes and landforms provide the template upon which the valued wildlife habitats have developed. Some reserves have been established to protect near-pristine habitats, such as the peat bogs, estuary, and coastal sand dunes near Ynyslas, Ceredigion, while others have been artificially created in mitigation for loss of habitat elsewhere, a prime case being Newport Wetlands on the Severn Estuary. In such anthropogenic wetland landscapes (Reason 8), geomorphology can provide a key input to the design of management strategies, which may focus on maximising ecosystem services, including enhancing biodiversity, providing protection from coastal surges, and promoting carbon sequestration.

log jam 3Outside of protected areas, geomorphology can also play a role in developing strategies for restoration of degraded landscapes, including peatlands, hillslopes and river channels. For instance, in the Cwmparc catchment near Treorchy, Rhondda Cynon Taff, ongoing geomorphological research is helping to evaluate proposed sustainable flood management strategies, including the effectiveness of using engineered log jams to slow flood flows along heavily modified channels (Photo: Stephen Tooth). Geomorphology is also providing key inputs to the design of the coastal defence schemes that are being implemented along many parts of the Welsh coastline, such as at Borth, Ceredigion, where an artificially-constructed reef, rock groynes and breakwaters, and beach nourishment are parts of an overall strategy to protect properties from extreme coastal storms and longer term sea level rise (Reason 9). With mounting concern over habitat loss and likely future increases in the frequency and magnitude of geomorphological hazards (e.g. intense rainfall, river flooding, coastal surges), such trends are likely to continue in years to come.

Did you know? The importance of embedding geomorphological knowledge in environmental management sometimes only becomes apparent where engineering schemes and management strategies have failed. A classic example is provided by a reach of the middle Ystwyth River near Llanilar, Ceredigion. In 1864, the naturally meandering, gravel-bed river was artificially straightened to run adjacent to a railway track but historic maps show that meanders re-established during the next 100 years. In 1969, an artificially straight channel with a trapeizodal cross-section and flat bed was again engineered but without any bank protection works taking place. Within a few months, following a period of high winter flows, the channel had again transformed into a meandering channel with a more irregular cross section. Numerous gravel bars and pools had established along the bed and steep, vertical banks had formed locally (Source: Lewin, J. 1976. Initiation of bed forms and meanders in coarse-grained sediment. Geological Society of America Bulletin, v.87, pp.281-285). The local river authority made further several attempts to re-straighten the channel but such efforts also failed, and ultimately the authorities engineered a meandering channel. This example shows how a variable flow regime that responds rapidly to rainfall, a mobile gravel bed, and unstable banks can combine to give rise to a naturally dynamic, sinuous channel that confounds engineering efforts to artificially straighten and confine its course. In mid Wales and farther afield, this combination of factors is not uncommon (e.g. see Reason 4 and Reason 5). Nonetheless, the lesson seems to be a hard one to learn, for throughout Wales, there are numerous examples of channel re-alignment and bank protection schemes that have failed owing to an inability to take full account of the underlying geomorphological processes.

10 Reasons Why …. 10 Rheswm Pam …. : 9

Monday 30th November 2015

Blog post 9 of 10 about the geomorphology of Wales. Click on images to view larger version in a separate window. Parallel blog in Welsh at http://hywelgriffiths.blogspot.co.uk/

Reason 9. The Earth’s landscapes are becoming more hazardous. Both global environmental change and human activities are increasing the magnitude and frequency of geomorphological hazards, which occur wherever and whenever land surface stability is affected and adverse socio-economic impacts are experienced.

Throughout Welsh history, various geomorphological processes – many of them related to extreme events – have represented hazards to local communities. Being located in the temperate mid latitudes far from tectonic plate boundaries, in recent millennia Wales has been largely unaffected by the various hazards posed by extreme events such as glacial outburst floods, tsunami and volcanic eruptions, while earthquakes are a relatively infrequent occurrence (Reason 2). By contrast, given frequent intense and/or prolonged rainfall, a lengthy coastline that is exposed to Atlantic swells, and much steeply sloping terrain, extreme events such as river and coastal flooding, rockfalls, and landslides are common hazards. While such events may result from entirely natural causes, human factors can enhance their severity, possibly increasing the damage to infrastructure and/or the loss of human lives.

IMG_4450 reducedThe events that took place in the small village of Dolgarrog, Conway, provide a case in point. Following a period of heavy rainfall that had started in mid October, on the evening of 2nd November 1925, the dam wall of the Llyn Eigiau reservoir in the Carnedd Mountains was breached. The breach released water that flowed downstream and then overtopped and breached the dam wall on the Coedty reservoir. Collective failure of the two dams caused a flood that continued along the Afon Porth Llwyd, rapidly cascading down its steep escarpment course towards Dolgarrog. The water and many thousands of tonnes of transported debris inundated part of the village, forming a fan with imbricated (stacked) boulders up to several metres in diameter on the western margin of the River Conwy floodplain (Photo: Stephen Tooth). 16 people lost their lives in the disaster, a figure that would have been much higher had many villagers not been watching a film in the local theatre (Source: Fearnsides, W.G. and Wilcockson, W.H. 1928. A topographical study of the flood-swept course of the Porth Llwyd above Dolgarrog. The Geographical Journal, v.72, pp.401-416). In 2004, a memorial trail was created through the boulder fan, and this serves as a sobering reminder of the lasting impacts that such extreme events can have on local communities.

On 21st October 2016, the 50th anniversary of the disaster in Aberfan, Merthyr Tydfil, will also provide pause for reflection. In this instance, a toxic combination of several days of heavy rainfall and negligent management practices contributed to failure of a local colliery spoil tip on the side of Mynydd Merthyr, liberating over 150 000 m3 of water-saturated debris. Some of the debris was re-deposited on the lower slopes of the mountain, but some 40 000 m3 continued as a viscous flow more than 10 m deep, rapidly inundating parts of the village, including the classrooms at Pantglas Junior School. 144 people, the majority of them schoolchildren, died in the disaster (Source: https://en.wikipedia.org/wiki/Aberfan_disaster; http://www.nuffield.ox.ac.uk/politics/aberfan/home.htm).

IMG_9074 reduced

IMG_9065 reducedAround Wales’s coastline, extreme coastal storms represent some of the biggest geomorphological hazards. Recently, this was illustrated to dramatic effect along the seafront in Aberystwyth, Ceredigion, which was subject to a succession of high tides and high-energy wave events in the winter of 2013/14. In the most extreme event (early January 2014), the ground floors and basements of many seafront properties were flooded, paving slabs were eroded, and large volumes of sand and gravel were deposited across the promenade, roads and car parks (Photos: Stephen Tooth). While many parts of the seawall survived unscathed, in at least one place, the wall was breached, and erosion of the backfill lead to subsidence and partial collapse of a seafront shelter (for an animated 3D laser scan of the damaged shelter, see https://www.youtube.com/watch?v=8S9YFmPNTHI). As a Grade II-listed structure, the building material was salvaged and the shelter later reconstructed, and other parts of the seafront were quickly cleaned up and repaired. While such events are dramatic, and had never before been witnessed by many local residents, they are certainly not unprecedented, for significant damage to Aberystwyth’s seafront also had been caused by extreme storms in January 1938 and October 1927, as well as in earlier decades. Moreover, despite much of the media’s appetite, it may never be possible to attribute any individual extreme event to the impacts of global climate change. But in a world with rapidly rising sea levels, warmer average air temperatures and a more unstable atmosphere, such coastal storms may provide insights into the types of geomorphological hazards that in future may become more common along the Welsh coastline.

Did You Know? According to a Welsh government-sponsored report, 1 in 9 people in Wales live in properties that are at risk of flooding from rivers or the sea. In total, this represents 357 000 people and 220 000 properties (Environment Agency Wales, 2010. Future Flooding in Wales: Possible Long-Term Investment Scenarios. Available at: http://webarchive.nationalarchives.gov.uk/20140328084622/http://www.environment-agency.gov.uk/static/documents/Research/Flooding_in_Wales_Flood_defences_ENGLISH_V5.pdf). Many of these properties are located in towns and cities in the low-lying, densely populated coastal areas of north Wales and the post-industrial valleys and lowlands of the southeast, having been constructed when regulations on building in flood-prone areas were lax. With projections of future increases in inland and coastal flood frequency and magnitude, the number of flood-prone properties is likely to increase, with flood management likely to become one of Wales’s most pressing environmental management problems. Some of the impacts of extreme floods are obvious, such as the inundation and damage or destruction of property and infrastructure. Other impacts are less obvious but may be just as severe. For example, in the headwaters of many Welsh river catchments, historical mining activities have led to significant concentrations of heavy metals in floodplain sediments. During extreme floods, many of these sediments are re-mobilised by bank erosion, and then transported downstream and re-deposited on lower-elevation floodplains. This can result in widespread pollution of agricultural land and even domestic gardens. For example, levels of lead, zinc and cadmium locally have been found to be above recognised guideline values, and may pose significant risks to the health of grazing animals (Foulds, S.A., Brewer, P.A., Macklin, M.G., Haresign, W., Betson, R.E. and Rassner, S.M.E. 2014. Flood-related contamination in catchments affected by historical metal mining: an unexpected and emerging hazard of climate change. Science of the Total Environment, v.476, pp.165-180). Such studies show that despite the end of most metal mining over a century ago, its legacy continues to affect the Welsh population. Due to the largely invisible nature, however, this particular geomorphological hazard is often overlooked.

10 Reasons Why …. 10 Rheswm Pam …. : 8

Thursday 29th October 2015

Blog post 8 of 10 about the geomorphology of Wales. Click on images to view larger version in a separate window. Parallel blog in Welsh at http://hywelgriffiths.blogspot.co.uk/

Reason 8. Human activities are influencing landscape dynamics. Increasingly, many geomorphological processes and landform/landscape developments are influenced by human activities.

Across Wales, human activities influence geomorphological processes, landforms and landscapes, both indirectly and directly. Indirect influences include human-induced changes to animal populations or vegetation covers that may have an influence on hillslope runoff and sediment transfer, such as badger control programmes (Reason 2), afforestation or woodland felling. Direct influences include deliberate manipulation of geomorphological processes, and can either enhance natural rates of change, such as by promoting river meander cutoffs as part of channel straightening projects (Reason 5), or suppress natural rates of change, such as through river bank or coastal protection works (Reason 7).

anthropogenic influences

In recognition of the widespread influence of human activities on the Earth’s surface, the term ‘Anthropocene’ has been proposed as a new geological time interval. Have human activities become the dominant influence on the shaping of the Earth’s surface, and if so, will these activities leave an imprint in the long-term, future geological record? In Wales, as elsewhere, vigorous debate surrounds the merits of this proposed new time interval, in part because it is not easy to assess the relative importance of natural extreme events (e.g. earthquakes or rare floods – Reason 2 and Reason 4), internal landform adjustments (Reason 5), and human activities as influences on landform/landscape development and the long-term geological record. Natural extreme events, for instance, can accomplish rapid geomorphic change, perhaps undoing many decades of human engineering and infrastructural developments, as was seen in the winter 2014/2015 coastal storms and floods that damaged many parts of the Welsh coastline (see forthcoming Reason 9). Nevertheless, there is no doubt that many human activities in Wales – indirectly or directly – involve the movement of mass (rock, sediment and water) at rates that vastly exceed natural rates, and in ways that will persist far into the geological future. This is most visible in the case of mining activities, such as Electric Mountain near Llanberis, Gwynedd, where vast quantities of high-quality slate have been removed to leave a terraced hillside that towers above Dinorwic Power Station (upper photo: Denis Egan – www.flickr.com/photos/theancientbrit/288064095/, reproduced under Creative Commons licence). Other spectacular examples include the copper mines on Parys Mountain, Anglesey, or the open cast coal mines of the south Wales valleys. Other highly visible human impacts on natural hydrological and sedimentary cycles occur as a result of activities such as dam building, reservoir construction and inter-basin water transfer schemes, as exemplified in the Elan valley, Powys (lower photo: Stephen Tooth), while many coastal areas have been affected by estuary dredging, beach replenishment, and coastal dune landscaping (see ‘Did You Know?’ below).

glass & plastics

Other indirect and direct human activities are far less visible, but nonetheless may still be impacting on geomorphological processes, landforms and landscapes across Wales. For instance, along many parts of the Welsh coastline, a variety of human-made materials such as glass, house bricks, ceramics, metals and plastics now form a small, but perceptible and still growing, component of beach sediments. The long-term significance of these materials, both geomorphologically and in wider environmental terms, is open to debate. Glass ‘pebbles’ recovered from South Beach in Aberystwyth, Ceredigion (upper photo), are relatively benign, as glass is made primarily from commonly-occurring natural elements (mainly silica, sodium carbonate and calcium carbonate). Although persisting in sediments, glass will undergo rapid physical break down under the influence of high-energy or extreme wave and swash conditions. By contrast, many plastics, such as the beads recovered from Whitesands beach, Pembrokeshire (lower photo), are human-made polymers derived from petrochemicals (hydrocarbons). Some plastics will persist in sediments but also may represent a more insidious problem, as it is thought that their physical and chemical break down may facilitate ingestion by marine organisms. In Wales and farther afield, this is leading to fears that plastics are entering the food chain, with as yet poorly understood implications for human health (Photos: Stephen Tooth).

Did You Know? Kenfig National Nature Reserve in Glamorgan is one of the last remnants of a large 3300 ha (33 km2) dune system that once stretched more-or-less continuously along part of the south Wales coastline from the Gower Peninsula in the west to the River Ogmore in the east. Over the last century, however, many of these coastal dunes have been lost to urban, industrial and recreational developments, including caravan parks and golf courses, while others have become overgrown and stabilised by vegetation such as marram grass (Ammophila arenaria). Some estimates suggest that over the last 50 years, 64% of areas of open, mobile sand dunes have been lost from the Welsh coastline as a whole, eliminating the conditions necessary for a variety of rare plants and insects to flourish. These include the threatened fen orchid (Liparis loeslelii), marsh helleborine (Epipactis palustris), the vernal bee (Colletes cunicularius) and the dune tiger beetle (Cicindela maritime). Loss of mobile dunes has occurred even in protected sites such as Kenfig, so in recent years, heavy vehicles have been shifting tons of sand at the site to recreate ‘natural’ dune blowouts and slacks, which are characterised by regular wind disturbance and more mobile, open sand surfaces (http://www.bbc.co.uk/nature/17339061). Given Kenfig’s protected status, creating new habitat from the deliberate loss of some existing habitat might raise some eyebrows, but the policy has been deemed ‘destructively constructive’; in other words, a necessary risk to provide the habitat essential for ensuring the survival of rare species. From this example, the influence of human activities on Welsh landscape dynamics can be seen clearly, and both now and in the future, such deliberate earth moving is likely to form an increasingly important part of much environmental management.

10 Reasons Why …. 10 Rheswm Pam …. : 7

Monday 28th September 2015

Blog post 7 of 10 about the geomorphology of Wales. Click on images to view larger versions in separate windows. Parallel blog in Welsh at http://hywelgriffiths.blogspot.co.uk/

Reason 7. Global change is influencing landscape dynamics. Ongoing global environmental change, which includes atmospheric warming and sea level rise, is currently driving landform development, including desert lake desiccation, ice sheet and glacial retreat, and coastline erosion.

mires

Being located in the temperate mid latitudes far from desert lakes, ice sheets and glaciers, some of these landscape dynamics appear to be of little direct relevance to Wales. But sea level rise and coastal erosion is certainly an issue along large parts of the Welsh coastline (see below), and global environmental change is driving other forms of landscape development. For instance, many parts of the Welsh uplands are covered by blanket mires (‘bogs’), which are characterised by peat that is draped across the underlying topography. Mires are major carbon sinks, being formed from partly decomposed plant material that has built up over many thousands of years under typically cool, waterlogged, oxygen-starved conditions. Today, however, many areas of blanket mire are degraded and actively eroding, as seen from Bwlch Y Groes in Gwynedd, one of the highest public road mountain passes in Wales (left photo: eroding mire is visible on the hilltop in the far distance). Mire degradation can be driven by a combination of factors, including overgrazing, overburning, and air pollution but global atmospheric warming is almost certainly playing a role, particularly through subtle changes to upland water balances. A warmer, more variable climate can lead to longer and/or more frequent dry periods, thereby reducing the extent and duration of waterlogging. This enables oxidation of the peat and promotes increased rates of microbial breakdown of the dead plant matter, with some of the solid carbon being converted to carbon dioxide gas. Drier mires are more vulnerable to extreme fires, leading to loss of peat through combustion, a process that also generates carbon dioxide. Drier, fire-affected mires may also be susceptible to gully erosion (right photo), especially during subsequent extreme rainfall events. Gully erosion may be associated with rapid lowering of water tables, leading to further peat oxidation and carbon dioxide generation. Hence, rather than remaining as a carbon sink, extensively degrading and eroding blanket mires may ultimately become a net source of atmospheric carbon dioxide, so adding to the ever-increasing burden of greenhouse gases and providing a positive feedback in an already warming climate (Photos: Stephen Tooth).

Llyn cliff erosion

While a large percentage of the Welsh landmass lies well above sea level (Reason 1), the country nonetheless possesses a lengthy coastline. Much of this coastline is characterised by headlands formed of resistant rock, and intervening bays formed in more erodible rocks or sediments, as exemplified in Pembrokeshire (Reason 3) or along the Llŷn Peninsula. These erodible rocks and sediments may be vulnerable to increased erosion under rising sea levels, particularly if higher seas are accompanied by an increased frequency of extreme storm events. For instance, in Aberdaron Bay, located near the western tip of the Llŷn Peninsula, coastal erosion is pronounced where the 20 m high cliffs are formed in weakly-consolidated glacial sediments that are comprised principally of sand, silt and clay. Erosion of the base of the cliffs is leading to slumping and collapse of the entire cliff face (upper left photo). Along the eastern part of the bay, the cliff is retreating mainly into agricultural land but farther west, the erosion threatens a nearby road, a church cemetery and other buildings. In response to this threat, an elaborate coastal defence scheme has included sea wall construction and chevron-style drainage on the cliff face (upper right and lower photo) (Photos: Stephen Tooth. Aerial imagery from Google Earth, 0.72 km across, with north oriented to the top).

Did You Know? How long is the coastline of Wales? The answer partly depends on the scale of the map that is used for the measurement, as the larger the map scale, the more ‘wiggly’ the coastline appears to be, and so the longer the length that can be measured. Whether measurements are made at high tide, low tide or somewhere in between could also make a difference. Using 1:10 000 maps and measuring along the mean high water mark, mainland Wales’s coastline is said to be about 1317 miles (2120 km) long, while adding the islands of Anglesey and Holyhead increases the figure to 1680 miles (2740 km) (Source: The British Cartographic Society – http://www.cartography.org.uk/default.asp?contentID=749). But with rising sea levels, even that figure may change over time, as some beaches may narrow or disappear owing to inundation or erosion, while others perhaps get wider as retreating cliffs generate greater sediment supply. Around the Welsh coastline, recognition of a rapidly changing coastline is leading to serious debates about future priorities for coastal defence schemes. While some communities have benefitted from extensive investment in coastal protection works in recent years (e.g. http://www.bbc.co.uk/news/uk-wales-mid-wales-16105700), there is tacit acknowledgement that not everywhere can continue to be protected, with other communities possibly facing the prospect of abandonment as sea levels rise further (e.g. http://www.bbc.co.uk/news/uk-wales-26495935).