Median line: A century of border violence and the alluvial geopolitics of the Evros/Meriç/Maritsa River border

The border river of the Evros/Meriç/Maritsa has been shaped during the century since its demarcation by the Lausanne peace treaty. Over this period, a dense overlap of environmental, geopolitical, legal and cultural actors has turned it into both a riverised border and a borderised river. The border regime appropriates the riverine characteristics of flow, erosion, mud, turbulence and fog as much as it is founded on military technology, international law, agricultural and conservation practices, resource logistics, border crossing and the denial thereof

making of a river border.Between the riverine qualities of the border, and the perception of the borderine qualities of the river, a specific type of river (borderised) and a specific type of border (riverine) has been shaped.Borderine is used here to identify features that a militarised view of physical geography identifies as defensive (banks, muds, plants, flow velocity, depth etc.), and by deploying them over time these seemingly innocuous features have become increasingly deadly.Developing Reece Jones' argument that 'the existence of the border itself produces the violence that surrounds it', exclusionary violence operates at multiple scales and aspects of life, from the direct violence concentrated at borderzones or structural forms of violence such as economic exclusion, and resource enclosure (Jones, 2016;Topak, 2021).Polly Pallister-Wilkins has traced the co-option of 'humanitarian' discourse by border police at Evros, a trend that has all but disappeared in recent years, to address the imbalanced paradox central to border policing: the political demand to protect territory and the lives of those people trying to cross territorial boundaries (Pallister-Wilkins, 2015, p. 60).The abdication of responsibility of the latter is in many parts facilitated by the river ecosystem within which the police enact the violent practices of pushbacks.By placing contemporary violent bordering conditions within a longer time frame, we argue that the production of the river as alibi for state violence is rooted in the original bordering processes, and furthermore, that the decision to demarcate along a river is a political act with deadly results.

| THE SHIFTING SANDS OF DEMARCATION
While many examples of international river border law specify that the demarcation of navigable rivers should follow the 'thalweg', an antiquated term derived from the German for valley ('Thal') and way ('Weg') that refers to the line of a watercourse's lowest elevation, in Evros/Meriç this is not the case. 6Section 1 of the Athens protocol II states that the border line was tethered to the median line measured against the two banks fixed to their 1920s position: the frontier line will not follow the river in its eventual displacements, but this line is determined in a definitive manner by the current position of the river.
Both the acknowledgement that the river will be displaced and the simultaneous oversight of the eventual displacements of the sand 'without taking into consideration the sandbanks' are crucial.The constellation-like diagram below (Figure 1) shows the demarcation committee's triangulation process for measuring the river near to the delta.Representatives of each nation were overseen by a Dutch engineer Lt. Colonel Backer, the president of the international committee.Each is depicted on the map occupying a location from which the line was measured.The triangulation was made against key points on each bank, and points set further back.One is an old fortress, others are significant trees-landscape features that are hard to trace a century later.The map depicts the decision to demarcate along one of the two main courses that straddle the delta, themselves later subject to channelling.It is appropriate that the fixed points are drawn onto a blank page as they do not account for the interwoven coastal rivers, marshes, muds, shoals, sands and lagoons that comprise the deltaic ecosystem.Indeed, the diagram reflects the general disregard in the triangulation of border demarcations for the temporal question of the future geomorphology within which they are set.
John Donaldson has written extensively on the international law of river borders, with specific focus on accretion and avulsion as legal terms that identify the spatio-temporal movements of river courses (Donaldson, 2011, p. 155).Accretion is defined as the slow, and crucially, imperceptible movement of a river whereby a border shifts laterally with the central channel (pp. 158-160).Avulsion, on the other hand, is an acute and perceptible deviation of a river course to produce, for example, a major change in deltaic plumes, the emergence of a large looping meander after floods, or conversely, a 'river cutting through the "neck" of such a meander ' (p. 165).
Unlike the abstraction of the diagram above, the map in Figure 2 shows the changes that have taken place on a short section of river near to the delta and is determined from aerial photography at intervals between the 1926 demarcation and the present.In some places, the river has shifted to one side of the 1926 line before sweeping back to its present course on the other side.Drawing a definitive line in the context of these changes makes a river border contingent upon fluvial geomorphological time and process.
For these reasons, rivers and other geomorphological features are inadequate political boundaries, as Donaldson suggests 'the presence of water makes a boundary river unstable, forceful and risky; incompatible with the legal fiction of a fixed boundary line that would prefer the stability of land over the dynamism of water' (Donaldson, 2011, p. 167). 7We think of these processes alongside Philip Steinberg and Kimberley Peters who have conceptualised both a 'wet ontology' and a 'more-than-wet ontology' to reimagine the world on liquid terms and accommodate for water's constant interaction with other elements and materials (Peters & Steinberg, 2019;Steinberg & Peters, 2015).The sandbanks, which are noted but expressly not taken into consideration in Section 1 of the demarcation protocol, are of increasing relevance as the ongoing interactions between water and alluvial sands and soils (Bremner, 2021) destabilise the river border.Like the parcels, they are produced geomorphologically, and today we cannot think of the river border without its sands and sediments.

| ISLANDS AND ISLETS
Islands are crucial features of a fluvial geomorphological perspective on the politics of river borders.During an interview in April 2022, Stamatis Zogaris, from the Hellenic Centre for Marine Research, described to us 219 islands and islets of the river (Zogaris et al., 2015) and how from the boat it is unclear to which state an island belongs.An expert on the flora and fauna of the river, Zogaris identified the islands as alluvial formations of the erosion and deposition of sediments and woody materials that reflect the complexity and scale of the ecosystem.
While the sands were dismissed as non-territory in the protocol, due to the inherent instability of alluvial transportation, their loss from one side and accretion on the other is critical for understanding how the Evros/Meriç is policed.Dilip da Cunha has shown that the drawn line of a riverbank almost always takes precedence over the flow of water.
After all, rivers do not cease to exist when they are without water […].What remains is a space between lines which continues to be seen and enforced as a 'river' or a 'river bed', suggesting that it is the line more than water that is essential to rivers.
(da Cunha, 2018, p. 4) The century of fluvial geomorphological variation between the drawn border and the river (Figure 2) shows that as far as demarcation is concerned, once the line has been drawn the water itself is no longer relevant.For the arcifinious imaginary of the state, however, the water remains essential to its weaponisation of the environment. 8This contradiction between the relevance of water for demarcation and policing is necessary for understanding how the river border is produced as an ambiguous territory, and therefore a space of state violence.When the main channel shifts but the demarcated median line does not, the border river becomes de-watered.This is confusing for asylum seekers, as Kuzey, one of our interlocutors pushed back five times in May 2019, describes when he accidentally crossed the border-but not the river-into Greece and found himself trapped in one of these pockets: I didn't know that I was on the Greek side of the border.I was just walking in the forest, thinking I was on the Turkish side of the border.I see a bridge.That shocked me because I never think that there would be a bridge in the river.I carefully crossed the bridge.I found a hut.I saw some farmer things: bags with fertiliser.The writing on them was not Turkish.They were in Greek language.That time I noticed I may be in the Greek side of the border, but I know I was in the Turkish side of the river, but I was not sure.Kuzey had crossed the border but not the trespass line.He spent 2 days stranded in that parcel of land, hiding inside an irrigation plant without food or the ability to light a fire, too exhausted to swim again and too scared to cross the bridge on foot.
One reason that river boundaries can be advantageous for bordering states, however, is exactly because of this capricious nature.When rivers shift, one side gains territory and the other loses it, the emergence and movement of alluvial islands can thus enable the possibility of territorial claims.In Evros/Meriç, however, bordering states increasingly manipulate the 'legal fiction' of the fixed boundary line for quite the opposite intention.When asylum seekers find themselves trapped in these interstitial spaces, the two littoral states do not claim the shifting or emerging islands but deny their claim in order to denounce the humanitarian responsibility for rescue.
In late February 2020, the Evros/Meriç became a flash point, when the Turkish government opened its borders with Greece to exert political pressure on the EU over conflict in Syria.It directed thousands of refugees to the Evros/Meriç with the false promise of an open route to Europe.The Greek government responded by suspending its asylum system and deploying police and military to the region.Tensions lasted for several days, during which time at least two asylum seekers lost their lives to Greek bullets, including the murder of Muhammad al-Arab on 2 March 2020.Forensic Architecture found that Greek soldiers were firing across a now dry section of riverbed in the delta at asylum seekers stranded in an isolated parcel of land not far from the now fenced section where Serhat Karadeniz and his compatriot were trapped in April 2023. 9As shown in this example, when a now dry section of the old riverbed is the border, the area between it and the new river course becomes caught between the border line and the border river.In this space, isolated between the two states, the Greek state violates migrants' rights.

| ISLANDS OF HYPERLEGALITY
Frontiers have historically been imagined and constructed as spaces of lawlessness, wild places where things that would not be possible elsewhere can happen.As Elizabeth Povinelli points out, 'on the frontier ruthless tactics are justified; the law can be suspended in relation to them' (2018).Likewise, Alison Mountz conceives of archipelagos and islands as spaces where the political imaginary of power is performed through the offshoring of border detention and enforcement.The violent pushbacks to the sediment islands and islets of the Ervos/Meriç are made possible in the frontier environment (Mountz, 2011).Critical border scholars Prem Kumar Rajaram and Carl Grundy-Warr suggest that the exposure of border crossers to fatal forces is the operation of 'the zones of exemption' where 'sovereign power cease[s] to function' (Rajaram & Grundy-Warr, 2004, p. 38).However, in relation to the Evros/Meriç fluvial frontier, rather than a space of exemption, sovereign power does not cease to function but incorporates the river's ambiguities in the production of acts of border violence.The frontier reveals itself as an excess of law (Evans, 2009) rather than its absence-not the cessation of power's function but its very purpose.The very drawing of a fixed yet imaginary median line along the central course of the river, and a second line along the limits of its floodplain, to delineate the military buffer zone, effectively produce the river as a frontier, whereby its movements and muds become spaces where sovereign territorial imaginaries are projected.
As we will discuss, in Evros/Meriç obscure actors and legal excess are often compounded by the shifting geography of the river so that different states can de facto 'redraw' their borders to selectively include or renounce sandbanks.Such cases show that as the river moves the 'legal fiction' of the border line is woven through contested and uncertain jurisdictions making it difficult to ascertain what law applies (Greek, Turkish or neither).It is in these moments that the border becomes hyperlegal.
The term hyperlegality was coined by the legal scholar Nasser Hussain to place the specific anti-terror legislation enacted after 9/11 within the longer timeframe of British colonial law.He defines this legislative structure as operating within two mechanisms: firstly, 'the increasing use of classifications of persons in the law', elaborating on the received legal categories such as criminal, citizen, immigrant to include further subcategories like 'enemy combatant, security threat immigrant'; and secondly, 'the use of special tribunals and commissions' to override existing legal structures (Hussain, 2007, p. 516).Indeed, regarding the systematisation of pushbacks since the 1990s and before, a former Greek Police officer told the activist group InfoMigrants in 2021 that 'The border area is a military zone.It's not complicated, no one is watching us'. 10 These words show how the production of a militarised zone is a legal structure that enables usually illegal policing and patrolling activity under the umbrella of the special territorial conditions of potential international conflict.
Our use of hyperlegality in the context of bordering and pushbacks in the Evros/Meriç aligns with and expands on Hussain's term to include the physical and environmental conditions.There are clear racial and ethnic classifications of people crossing the river, such as the connotations of those categorised as 'illegal' and 'irregular' migrants.This has implications for policing in the militarised zone through the processes of apprehension and detention in unofficial and semi-official 11 facilities nearby, where the inaccessibility of asylum procedures overrides existing EU human rights structures (though many of these spaces are EU funded), as well as the illegal and systematic practice of pushbacks.Like Serhat Karadeniz's video, social media is used at the Evros/Meriç, as at many borders, to counter such illegal practices.Social Media posts raise an alarm when people encounter adverse conditions and require immediate rescue, or as with Forensic Architecture's investigation into the case of Ayşe Erdoğan, people intending to claim asylum disseminate their geolocation within a sovereign territory in the knowledge that border guards might illegally and secretly push them back across the ambiguous terrain of the river border. 12 We consider hyperlegality to be enabled not only through militarisation, as indicated by the words of the police officer above, but also where territorial exception encounters the ways shifting islets insert the element of doubt as to where specific jurisdictions begin and end.Since early 2022, a paradigm shift in the practice of pushbacks in the region has been documented: instead of being expelled to the Turkish banks, people are being taken to these islets by Greek operatives and left there.Greek border guards are assumed to be doing this because they do not want to set foot on Turkish land and risk being apprehended or coming face-to-face with a Turkish patrol.Similarly, smugglers on the Turkish side increasingly direct asylum seekers to such islets and instruct them to wait for rescue from the Greek side, which often fails to arrive.Consequently, the islands and islets are manipulated by different actors to abandon people, leaving them trapped between Greece, the EU, Turkey and a century of geomorphological variation.Fundamentally, the border region of the Evros has not seen the 'withdrawal of law' (Hussain, 2007, p. 516); instead, law operates under the conditions of the border.This operation facilitates new categorisations of border crossers, new systems of detention and removal, all folded into deniability that is tied to the changing physical and environmental conditions.This legal-territorial imaginary turns the vectors and dynamics of the river into a weapon.
In one of many cases during July-August 2022 (Border Violence Monitoring Network (BVMN), 2022), a group of 38 asylum seekers were pushed back and stranded on an islet near to the village of Kissari.Following weeks of abandonment, and the reported death of a 5-year-old girl and two more travellers, the Greek government acknowledged that the group were there but denied rescue, claiming the islet, which according to the ministry of migration did not exist when the line was drawn in 1926, is Turkish. 13Months later, a map released by the Hellenic Army Geographical Service determined the islet was in fact split between the two countries.Compared against GPS locations shared by the group, the border line made public by the army demonstrated that the group moved for weeks between the two countries, seemingly unaware where one ended and the other began.Only then did it become clear that the Greek government was appearing to cede sovereign claim over its part of the islet in an attempt to deflect responsibility for the stranded people.
The emergence of islands of hyperlegality that did not exist in 1926 adds further weight to the inadequacy of the river as border.This became obvious during another case, in March 2022, when the EU Court of Human Rights (ECtHR) was itself unclear as to where demarcation lies and where its jurisdiction ends.This confusion was made clear when they ruled that Greece provide a group on an islet near the Greek village of Neo Cheimonio with 'food, clothing, water, and adequate medical care', 'if the islet is in the Greek jurisdiction'. 14Territorial uncertainty at an EU level causes delays in proceedings that may prove fatal for the people left in cold temperatures and difficult weather conditions by pushbacks with no access to medical treatment, as with the death of a 4-year-old boy who drowned while stranded with the group on this islet in 2022. 15In such cases where the ECtHR and the Greek government try to ascertain or withhold exactly where their riverine borders start and end, people are effectively detained within a riverine carceral archipelago of territorial indeterminacy and thus intentionally exposed to the deadly 'legal fiction' of the river border.

| CONCLUSION
Two rivers and two borders exist at the Evros/Meriç: the cartographic border of the old median line (in places a dry riverbed or stagnant backwater) and that of the new course, which has become the water of the new trespass line-but not the political borderline.River bordering is an ongoing process of adaptation, including changing socio-cultural, geopolitical and physical conditions.A full understanding of policing and patrolling methods, both explicit and covert, requires spatial and temporal knowledge of the ecological and geographic conditions of the river in the past and present.As we have shown in contexts of heightened militarisation and border mobility, the dynamism of rivers and their geomorphology is politically important.
Recent examples of the intensified fortification of the Evros, such as a 5 m high steel fence planned to stretch 160 km of the 218 km of river border 16 and designed to double as a flood defence embankment, suggest that the border regime is not only enlisting the river, and in doing so changing it (Jones, 2016, 246), but reaffirms our previously held hypothesis that the border is being designed and policed through hydraulic infrastructures (Alvarez, 2019a(Alvarez, , 2019b)).In such cases, policing and environmental control are enfolded together so that they are no longer easy to distinguish.Indeed, the fence does not so much act as a barrier where the river ends, but instead the river, barrier, islands and islets, and flood-defence levees are amalgamated as a hydraulic border.This composition emerges as a legal-territorial trap for those stranded and illegally expelled, such as Serhat Karadeniz caught between river and fence/flood defence and the many people abandoned on islets.
The process of making a river a border dates back to its original demarcation.The Evros/Meric has become a different river to the one encountered in the 1920s, one where its borderly characteristics have been emphasised over its connective ecological qualities.This history has real effects for those trying to seek asylum, those caught in the territorial limbo of an island that has shifted from one side of a line to another, or between the river and a fence.The Evros is an alluvial archive of a century of imbricating physical change and border violence.The river's continually shifting sands, islets and parcels of ambiguous land are the setting for a dense overlapping of agents and jurisdictions that shape the border's islands of hyerlegality where state violence is enacted with impunity.

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I G U R E 1 Triangulation A La Région Du Delta Dela Maritza, Commission De Délimitation De La Frontiére Gréco-Turque.Protocole des conclusions de la commission/Traite de Lausanne du 24 Juillet 1923, 1926.[Triangulation of the Martisa River delta region, Commission for Delimitation of the Greek-Turkish Border.Protocol of the conclusions of the commission/Treaty of Lausanne of 24 July 1923, 1926].