Storm Surge 2013 : One Year On - Part Four : Spurn

by @cloudskinner

This is the fourth and final installment of our mini-series looking back over the year since the 5 December 2013 storm surge, which flooded many areas in the Humber Estuary and along the east coast of the UK. The first part, Modelling the Surge, looked at the research that has been conducted since the storm surge and has advanced our knowledge and understanding of these events in the Humber. Part Two, What we Learnt, focused on the 2014 Humber Conference and the lessons that have been learnt over the year. Last week guest blogger, Jazmin Scarlett, told us about some of the often unseen impacts of flooding, the mental health issues that can arise, and how communities band together after disasters.

For the final part I want to take a longer look into the future and try and predict what it has in store for Spurn. Spurn, or Spurn Point as it is commonly known, is a piece of land that resembles a spit, sweeping out from the edge of the Holderness Coast and round into the estuary. It is important for several reasons: it hosts the signalling station for the Association of British Ports (ABP), kind of an air traffic control but for shipping; it is home to lifeboat crews (formerly permanently, with their families, but now just the crews whilst on shift), providing them quick and easy access to the North Sea and the estuary; it is an important site for migrating bird life, being a National Nature Reserve owned by Yorkshire Wildlife Trust; it keeps the mouth of the estuary narrow – it is not known what effect a wider mouth would have but it is expected that it could lead to a narrower channel with implications for shipping; and finally, it acts to guard the estuary from the full ravages of storms and waves.

When evaluating the true impact of the 5 December 2013 storm surge one cannot ignore Spurn. One of the most dramatic scenes from that night was the damage done to the landform, as highlighted in the LiDAR images below.

The breach at Spurn as shown by LiDAR data. Light Detection and Ranging (LiDAR) techniques uses rapid pulses of laser light to measure the elevation of the ground, both rapidly and in high detail. The top image shows the breached section of Spurn before 2013, and bottom image shows the same section measured shortly after the 5 December 2013 event 

(LiDAR data collected and provided by the Environment Agency).

It is clear that extensive damage was done by the waves and high water levels during the storm surge. The water will have over topped the narrow spit of land that separates the sea from the estuary, and washed the embankment down towards the estuary – you can see in the image that the bank has gone, and a mound of material has built to the left, on the estuary side.

There once was a road here at the breach site 

(author's own photo taken November 2014)

To understand the implications of this, and what the future might be, we need to delve into the past of Spurn. There are two theories behind the formation of Spurn which have emerged from two former University of Hull academics -

1. George de Boer long maintained that Spurn was a spit – material eroded from the Holderness Coast washes down via longshore drift, and is deposited as a long spit in the form of Spurn. Over time as the coast line retreats, this spit will be rapidly destroyed and another will form further back in line with the coast.
2. John Pethick disagreed however – He argued that Spurn was not a spit as such and had not retreated over time through repeated cycles of destruction. Rather, the end of Spurn is an island and had been in a fixed position throughout history, whilst the area between the island and coast is in a constant state of flux, sometimes forming a spit, sometimes a chain of islands and sometime open channel and sand banks. Although the location of this region has shifted over time with the coast, the end of Spurn has remained.

Until the 2013 storm surge both these theories were just academic. In his chapter of Neale and Flenley’s 1981 book, ‘The Quaternary in Britain’, de Boer recounts the recent history of Spurn and tells a tale of how it became a very man-made feature. He claimed that a cycle of destruction was taking hold in 1849, initiated by a violent storm (probably not unlike 5 December), and within a few years several wide and deep breaches formed along the narrow spit as it were then.

Water at high tide washing over the breached section of Spurn 

(author's own photo taken in November 2014)

In response, and to maintain the lighthouse and lifeboat crews housed there, the government at the time funded works to fill the breaches and huge loads of chalk from Barton-upon-Humber were dumped into the channels to fill them. Spurn came into the hands of the military and prior to WW1 the defences were bolstered and groynes put in place to let the spit grow. During both World Wars Spurn played an important role, not least in monitoring for possible enemy U-Boats infiltrating the estuary. It even had a railway line until 1951, and withstood the infamous 1953 storm surge with little damage.

In the 1960’s Spurn passed from military hands into the Yorkshire Naturalist’s Trust and eventually Yorkshire Wildlife Trust’s ownership, and the focus shifted from maintaining the hard, man-made structures of Spurn to the conservation of its environment and wildlife – as such the investment and work done to retain the defences has significantly decreased. I am sure George de Boer, if he were alive today, would suggest that the breach is the beginning of the cyclic destruction of Spurn that was stalled in the 1840’s.

View across the full breached section 

(author's own photo taken in November 2014)

I’m more inclined to side with John Pethick, however. Even if we were to just let nature take its course, I cannot envisage Spurn being utterly destroyed and replaced further into the estuary, nor do I think the evidence is strong for that having happened in the past, but it is clear that without huge investment to rebuild the spit as it were before 5 December, the nature of Spurn is going to change and will be in flux.

To predict what will happen to Spurn in the future, as the Holderness Coast retreats further back and sea levels rise, we need to adapt our models to be able to simulate some of these scenarios. Equally, it is important that we turn again the research of George de Boer and John Pethick, dig even further and try to understand the nature of Spurn; what it is, how it formed and how it has changed naturally in the past. Understanding that is the key to understanding its future.

Thanks to the Environment Agency and the Geomatics Team for the provision of LiDAR data used in this blog. This data was provided to University of Hull as part of the Dynamic Humber Project.

de Boer, G., 1981. Spurn Point : Erosion and Protection after 1849. IN: Neale, J., and Flenley, J., (eds). The Quaternary of Britain : Essays, reviews and original works on the Quaternary published in honour of Lewis Penny on his retirement. Pages 206 - 215. Pergamon Press, Oxford.

Colorado Rocks! Attending a research meeting on sedimentary systems

By Lucy Clarke (@DrLucyClarke)

  

Continuing the blog series looking at what we have been getting up to this summer...

Last week I was lucky enough to be in the US for a research conference and I'm sharing my experiences of this with you in this blog post. This was a specialist meeting, with about 50 people attending, focusing on the “Autogenic Dynamics of Sedimentary Systems” – so basically the importance of internal processes (i.e autogenic processes) in driving change in natural systems and how this is recorded in the 'rock record'.

You may be asking yourself... why is it important to understand what's recorded in the rock record? Well, geologists use this information to reconstruct long term environmental change. Layers of material are laid down through time and over lengthy time periods these form the rocks that we see all around us (i.e. a sedimentary system). By examining the grain size, composition and structures in these rocks it can tell us information about the type of processes that formed them and what the climate was like at the time using a technique called stratigraphy. So it's important to know not only how things like climate and tectonics can influence the sediment build up and preservation as it turns to rock, but also what effect other internal processes can have on this so that a correct interpretation can be made.

Stratigraphic profile from Colorado National Monument showing a fluvial section with thick layers of floodplain with thinner, coarser bands of channel material in between

The aim of the meeting was to bring together an interdisciplinary group of researchers from ecology, geochemistry, geography, geology, and palaeontology to look at the research advances that have been made in different sedimentary systems to evaluate what, if any, ‘autogenic’ signals can be determined. Presentations covered a range of topics and included field, numerical modelling and experimental approaches that were being used to try and tackle this problem.

I presented the research that I introduced in my blog on 28 August 2013: What drives change on alluvial fans? I talked about how my experiments showed that internal processes within these landforms caused observable changes in the flow patterns. 

The sessions were really interesting and thought provoking. It was designed to be a discussion rather than just a one-way presentation of information from the speakers, consequently we had lots of time for asking questions supplemented by break out groups to follow up on ideas and think about the 'bigger picture'. I found this particularly useful as it helped me to generate new ideas as to how to develop my own research, as well as starting to think about the wider implications of my research. Additionally having the opportunity to talk to people from other related, but slightly different disciplines, has certainly broadened my perspectives.

Looking over the Colorado River to the city of Grand Junction (to the left) and the Grand Junction Main Street (to the right)

The meeting was held in the city of Grand Junction - situated in central Colorado, the town sits on the Colorado River with lots of wineries and agricultural land surrounding it. Grand Junction is a small traditional mid-West town with a population of about 60,000 that boasts a university and a quaint main street that has a night market every Thursday evening during the summer. Temperatures were around 30°C every day and despite a couple of thunderstorms at the start of my trip the weather was great. Close to the town is the Colorado National Monument, this is a national park about 85 km² in size, containing stunning mesas and canyons. As part of the conference we were treated to a field day to experience the park's impressive geologic formations and see if we could explore, and apply, some of the conference themes in a field setting.

Colorado National Monument: looking over the national park (left) and geologists looking at a rock section showing preserved sand dunes (right)

I thoroughly enjoyed my week in Colorado. I got to explore a new area but most of all I made new connections for my research with the potential for new collaborations in the future. I learned about lots of current research from different, but related, areas that I hadn’t previously been aware of, which has rejuvenated my own research in this area - so all round it was a successful trip!

Enjoying the sunshine on the field day in Colorado National Monument

Iceland: a geographer’s paradise

By @DrLucyClarke

I recently co-led a 7-day undergraduate field trip to south-western Iceland.  This was my first visit to the country so I was really excited to see the land of fire and ice that I had heard so much about!  One of my motivations for becoming a geographer is my love of the outdoors, thirst for exploration and knowledge of new places and environments, so the field trip element of physical geography has therefore always held a huge appeal for me.  And to date my career has taken me to some amazing places - both within the UK and further afield.  So not surprisingly when I was approached to take part in the student field trip to Iceland, I jumped at the opportunity!

Iceland is a fascinating country - it lies between two continental plates, the Eurasian and the North American, that are constantly pulling away from each other.  The rift valley that this is creating is one of only two places in the world that you can see this happening on the Earth’s surface, the other being the Great Rift Valley of Eastern Africa. You can literally walk between, and next to,  the edge of actual continental plates and on some of the ‘youngest’ crustal surface on the planet.  This geographical rarity alone is reason to visit Iceland but this incredible place has much more has to offer!

Þingvellir: the rift valley in Iceland where the Eurasian and North American continental plates are pulling apart. The photos are showing the edge of the North American plate, with the lower photo looking out over the rift valley towards the Eurasian plate.

Iceland is also located over a hotspot (see the previous blog post by @volcanologist  for more information on hotspots), which is thought to have originally formed the island. This and the rift valley mean that Iceland is tectonically active, as you drive around, the horizon is littered with spectacular volcanoes and relict lava flows are dotted across the landscape.

The volcanic scenery in Iceland: the snow-capped summit of the volcano Hekla, the basalt cliffs at Vik formed from 3 distinct lava flows lying on top of one another, and the lava field from the 1783 Laki eruption (from left to right).

Not only do the volcanoes and related features provide a stunning backdrop, they are of interest to geologists to better understand how and why they erupt and what this means in relation to the inner workings of the Earth.  The rich history of Icelandic volcanic eruptions also provides a fantastic resource for geographers trying to understand the surface processes.  Each eruption deposits a layer of tephra across the ground in affected areas, these are then reburied by subsequent layers of soil through time. The composition, thickness and biota in these layers can tell us a lot about the environmental conditions occurring at the time of deposition (for example we can use the pollen as explained by @DrM_Farrell in one of her earlier blog posts).  The date of  these volcanic eruptions is well documented and, as each eruption has a unique signature, we can identify the date of the tephra layers and as such you can constrain the time periods of the other soil layers using a technique called stratigraphy.  This method has been used to better understand the influence that humans have had on the landscape since settlement in the 9^th century, the impact of deforestation and the effect of changing climate on soil formation and erosion.

A soil profile showing the distinctive black tephra layer at the top of the photo.

My main research area is the fluvial environment, so I was really excited to see the amazing braided rivers and waterfalls that Iceland had to offer, and I wasn’t disappointed! The scale of these are far greater than any in the UK and it was amazing to see them.  Below are some photos giving examples of some of the fluvial features we visited. The top row gives some examples from the many impressive waterfalls there are along the southern coast of Iceland. From left to right, these are Gullfoss (translated as Golden Falls), Hjálparfoss (Help Falls) and Skógafoss (Forest Falls). On the bottom row are images of some of the rivers, at either end are examples of braided river systems from the Þórsmörk valley into which the Eyjafjallajökull glacier (sitting on the slopes of the volcano that created havoc to European air space in 2010) drains. The high sediment load in the area creates these fantastic braided channels in the river systems. The middle picture on the bottom row shows the River Skeidará , the different colours represent the merging of water from two different sources, glacially fed water that has a heavy sediment load and fluvial (clearer) water.

As well as flowing water, as you can imagine Iceland also has plenty of frozen water and there are numerous glaciers and ice caps. The northerly location of Iceland -65° latitude mean that winters are cold and dark.   These cold conditions promote glacier formation.  On the field trip we investigated the geomorphological evidence for the retreat of the Skaftafell glacier which included a hike on the glacier ice of the Sólheimajökull glacier to measure the impact of debris cover on the glacier surface.  It was a great thrill for the students to get up close and personal with a real glacier.

Looking up the Skaftafell glacier from its terminus (left image), the glacier walk on the Sólheimajökull glacier (2 right hand images).

Field trips typically consist of long days in the field followed by long nights analysing the data with the students, so although the trip was hard work it certainly didn’t in any way detract from the awe of the place.  Iceland presents a fantastic opportunity to investigate a variety of geological and geographical processes and landforms, and experience incredible scenery.  As an added bonus I was also treated to my first ever viewing of the Northern Lights, as well an Arctic fox up close!

Arctic Fox

So overall I found my field trip to Iceland both exhilarating and exhausting, and I would wholeheartedly recommend Iceland as well worth a visit for anyone.  I’m certainly planning to go back for my own research so watch this space for updates…