Political Geography 107 (2023) 102975 Contents lists available at ScienceDirect Political Geography journal homepage: www.elsevier.com/locate/polgeo Full Length Article Where have all the sediments gone? Reservoir silting and sedimentary justice in the lower Ebro River Santiago Gorostiza a, b, *, Giacomo Parrinello b, Daniel Aguettaz-Vilchez b, David Saurí a a Departament de Geografia, Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona, Spain b Centre for History at Sciences Po, 27 Rue Saint-Guillaume, 75337, Paris cedex 07, France A B S T R A C T At the intersection of natural and social sciences, interest in river sedimentary fluxes and their alteration by human activities is increasing in the context of general retreat of delta formations. Since the 1950s, the construction of large dams in the main course of rivers has produced, among other impacts, a radical decrease in sedimentary fluxes — a key factor in the worldwide sedimentary crisis. While sediment accumulates in reservoirs, the resulting sediment scarcity downstream contributes to land subsidence and coastal erosion, endangering livelihoods in low lying areas such as river deltas. Focusing on the case of the Ebro River and delta (Spain), this article builds on Katherine Dawson’s notion of sedimentary justice to examine the articulation of a social demand to mobilise the sediments trapped in reservoirs to counter delta subsidence and coastal erosion. Using a historical perspective and paying attention to matters of both sediment quantity and quality, we show how this demand has developed hand in hand with the emergence of a scientific interpretation of the Ebro delta’s origins that emphasises non-human forces and the importance of sedimentary fluxes before human interferences. Activists have taken up this argument to demand the restoration of sedimentary fluxes, exposing corporate hydropower interests and insisting on the mobilisation of sediment trapped in reservoirs. Overall, by scrutinizing the power relations embedded in the immobilization of river sediments, this article contributes to recent work that integrates the materiality of sediment to the hydrosocial framework of analysis and argues that sedimentary justice provides new avenues to incorporate the non-human world to the literature on environmental and water justice. 1. Introduction sediments transported by the river (see Burgen in The Guardian, 2020). In a context of worldwide retreat of delta formations (Syvitski et al., In January 2020, the Eastern seaboard of the Iberian Peninsula was 2009), the retention of sediments in river reservoirs and the possibilities hit by Gloria, one of the most intense storms of recent decades. Damages to mobilise these sediments to preserve the delta’s morphology were to agriculture, tourism, and public infrastructure along the coast of raised as deeply political issues in front of declining liquid flows and Catalonia (Spain) amounted to some 70 million euros. One of the worst sediment transport in the Ebro (see Fig. 1). affected areas was the Ebro River delta, about 120 km south of Barce­ Similar to many other rivers throughout the world, the history of the lona. In the delta, home to 62.000 inhabitants and to one of the most Ebro during the second half of the 20th century shows how (some) important wetlands of the Western Mediterranean, the storm surge humans have become major actors in altering river sedimentary fluxes, penetrated 3 km inland inundating 3300 ha of rice fields and irrigation one of the signs indicating the beginning of a new geological era canals and destroying aquaculture facilities (Blay & Àvila, 2020). Im­ (Chakrabarty, 2021; Syvitski & Kettner, 2011). More than 100 billion ages showing almost the entire delta covered with water made a great metric tons of sediment have been trapped in reservoirs worldwide since impression on public opinion and raised fears that the worse scenarios the 1950s (Syvitski et al., 2005), drastically reducing sedimentary fluxes regarding the impacts of climate change were already happening. and directly contributing to the worldwide retreat of delta formations Accompanied by an acute sense of urgency, Gloria attracted the atten­ (Syvitski et al., 2009; Vörösmarty et al., 2003). In the Ebro case, the tion of national and international media to the sediments transported by dams built in the river during the 1960s contributed to a radical decrease the Ebro River or, more precisely, to the scarcity of these sediments and of sediment reaching the mouth (Vericat & Batalla, 2006). Since the its role in increasing exposure of the delta to storm surges and coastal 1970s, the reduction in the Ebro’s sediment load has been documented erosion. In the aftermath of the storm, local actors pointed to the man­ in scientific studies and was invoked in political debates about the agement of upstream dams as responsible for the meagre load of protection of the delta’s ecological value (Folch, 1976). From the 1980s * Corresponding author. Departament de Geografia, Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona, Spain. E-mail addresses: Santiago.gorostiza@uab.cat (S. Gorostiza), giacomo.parrinello@sciencespo.fr (G. Parrinello), daniel.aguettazvilchez@sciencespo.fr (D. Aguettaz-Vilchez), david.sauri@uab.cat (D. Saurí). https://doi.org/10.1016/j.polgeo.2023.102975 Received 27 July 2022; Received in revised form 24 July 2023; Accepted 4 September 2023 Available online 9 October 2023 0962-6298/© 2023 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by- nc-nd/4.0/). S. Gorostiza et al. Political Geography 107 (2023) 102975 to the 2000s, in response to state-sponsored water transfer projects from hydrosocial studies have increasingly paid attention to the materiality of the Ebro River to other regions in Spain, an alliance between social rivers, for the most part they have focused on the study of water flows, movements and scientists warned about the consequences that reduced not on sediment (de Micheaux, Mukherjee & Kull, 2018). Overall, the water flows could have in the quantity of sediments reaching the river Ebro case illustrates how the politicisation of sediment scarcity has mouth and therefore in delta subsidence, pointing to the intimate developed hand in hand with the transition from a hegemonic discourse connection between liquid flows and solid transport (Ibáñez et al., 1999; that portrays rivers as carriers of water for irrigation, drinking, and Ibáñez & Prat, 2003). Given the deteriorating scenario in the delta electricity production, to a new framing where water is much more than during the 2000s, social movements in the Ebro launched the Campanya H2O, and where sediments become crucially visible to social movements pels Sediments (“Campaign for Sediments”) aimed explicitly at making and institutional actors (Kondolf et al., 2019). visible the lack of sediments reaching the delta and demanding political Key to our study, the politicisation of sediment scarcity in the lower action to restore the transport of sediments immobilized in the Ebro Ebro hinges on the examination of different interpretations regarding reservoirs (Segarra, 2020). the delta’s origins and morphology. The morphology of river deltas in­ By exploring the case of the Ebro River since the 1960s, this paper volves submerged and emerged parts that, in the Mediterranean, are unravels the politicisation of sediment scarcity through the lens of mostly the product of complex and changing interactions between water sedimentary justice, described by Dawson (2021a) “as an entry point flows and sedimentary fluxes, sea level oscillations, and the bathymetric through which to unearth the power relations that govern deeply un­ characteristics of the coast (Caldwell et al., 2019; Cencini, 1998). In­ even claims over sediment”. Considering mobility as one of the central terpretations about the origins of deltas assign varying degrees of sig­ facets of sediment (Dawson, 2021a), we focus on the immobilization of nificance to human and non-human forces that influence sedimentary sediments produced by large reservoirs and the gradual emergence of fluxes. In the case of the Ebro, the traditional and long-established scientific and political proposals to revert the resulting sediment scarcity interpretation of the origins of the delta portrayed it as a product of downstream. By examining who benefits and suffers from the disruption historical human agency in the river basin since Roman times, empha­ that reservoirs cause to sedimentary fluxes we also explore an important sizing how human-induced erosion related to deforestation and agri­ facet of the social and historical lives of sediment, following Parrinello cultural activity boosted sedimentary fluxes and built the delta during and Kondolf’s (2021) call for more sediment-centric perspectives in the last few centuries (Bayerri, 1935; Deffontaines, 1951; Kleinpenning, social discourses. The concept of sedimentary justice (Dawson, 2021a) 1969; Pena, 1964). During the last decades, several researchers have makes evident that the water bias that Parrinello and Kondolf (2021) challenged this view of the delta as human-made and have instead observe in river and water history literature also applies to water justice emphasised the importance of non-human forces influencing sedimen­ and to critical accounts of water policy in Spain, which, for the most tary fluxes, arguing that older deltaic features were present before the part, have given little or no attention to sediment (Boelens et al., 2016; sea rose at the end of the last glacial period and that the progradation of Sauri & Del Moral, 2001; Swyngedouw, 2015). Similarly, while the current delta goes back approximately 6000 years (Cearreta et al., Fig. 1. The lower Ebro River, including the locations of the dams in the main stem of the river and the Ebro Delta Natural Park. Source: Authors. 2 S. Gorostiza et al. Political Geography 107 (2023) 102975 2016; Ibáñez et al., 1999). 2. The material and social life of sediments This argument concurs strongly with the move towards geologising the social sciences brought about by the Anthropocene concept, Encompassing a wide and highly heterogeneous number of sub­ attempting to bridge geological and human history (Chakrabarty, 2009). stances at the crossroads of geology, hydrology, and climate, sediment In the Ebro case, human agency as the main driving force in the for­ constitutes a basic component of river flows and of river life itself. The mation of the delta is in question. Moreover, for movements such as the historical relationships between river sediments and human societies Campaign for Sediments defending the mobilisation of sediments trap­ have been marked by a dialectic between associated benefits and risks. ped in reservoirs, the (partly) non-human origins of the delta is also a Both usually have a distinctive spatial component: erosion in the upper compelling argument for legitimizing both the power of sedimentary parts of catchments represents a hazard while sedimentation may create fluxes and the conservation of the delta that critically depends on them. problems downstream but mostly it may be considered as a resource in Hence researchers and activists portray the transfer of sediment trapped terms of soil fertility and ecosystem dynamics (Apitz, 2012), among in reservoirs and the restoration of sedimentary fluxes now restrained as other beneficial effects. All major civilizations flourishing near great the only solution to prevent the disappearance of the Ebro delta in the rivers have experienced this dual role of sediments as a blessing and a mid and long term (Canicio & Ibáñez, 1999; Cearreta et al., 2016; Ibáñez curse (Morris, 2012; Saikia, 2019; Zhang, 2016). et al., 2019; Segarra, 2020). In this regard, the Ebro case shows that On the one hand, sediment appears in the form of fertile soils, geological and historical interpretations of the delta’s past have political building materials, space for human habitation, and home to complex implications in present-day debates. webs of biotic resources at the interstices of terrestrial and aquatic en­ In theoretical terms, this case study advances the concept of sedi­ vironments (Apitz, 2012; Beiser, 2018; Walling & Fang, 2003). On the mentary justice (Dawson, 2021a) as part of the social and political life of other hand, however, sediment can turn into a formidable enemy as the sediments, connected to the material turn in Geography and more piling up of silt creates “perched” rivers circulating above floodplains broadly, in the social sciences (Bremner, 2020, 2021). By scrutinizing and making necessary the construction and continuous maintenance of the power relations embedded in sediments trapped in the Ebro reser­ dikes to contain floods. Excessive sediment loads silting reservoirs and voirs, we engage with Lafaye de Micheaux, Mukherjee and Kull’s (2018) raising riverbeds can become an obstacle for navigation and for dams. In call to incorporate the study of sediment to the hydrosocial cycle some cases, industrial activities developed since the late 19th century framework of analysis as a way to move past the land/water divide (De polluted waters and eventually sediments, which turned into hazardous Micheaux et al., 2018; Linton & Budds, 2014; Lahiri-Dutt, 2014). materials when reaching agricultural fields. Sedimentation thus could Following de Micheaux et al. (2018), we combine our engagement with turn into a major chemical hazard due to industrial pollution, one of the political ecology of water with insights from critical physical geography first documented examples being that of the Ashio Mine in Japan, in the in order to make visible the deep interconnections between biophysical early 20th century (Stolz, 2014). Therefore, in addition to quantity, the and social systems. Accordingly, our historical account of the politi­ quality of sediments could be also an issue of concern. cisation of sediment scarcity not only focuses on the interrelationships More recently, the interest in sediment and its environmental, social, between biophysical and social and historical processes (Lane, 2014) but and political implications has been approached in relation to climate also pays attention to the politics of environmental sciences (Dufour change, and especially in low-lying areas where their presence is et al., 2017; Lave, 2015; Lave et al., 2018). considered vital for offsetting the effects of subsidence, marine erosion, For our article we draw on archival and oral sources, which we and sea level rise as well as for producing rich biotic environments complemented with a survey of the press. We consulted the archives of (Bravard, 2018; Kondolf et al. 2018; Vörösmarty et al., 2003). A the Ebro River basin authority (Confederación Hidrográfica del Ebro), convergence of interests by the social and natural sciences on sediments the Diputació de Tarragona (the administrative body of the Tarragona can be currently detected, echoing the more developed sociohydrology province) and several municipal archives in the delta. In addition, we perspective in water studies (Best et al., 2022; Sivapalan et al., 2012). In carried out semi-structured interviews with activists involved in the the social sciences, some authors argue that debates about human Campanya pels Sediments, as well as with the engineer who led the first agency in global changes have reversed the indifference with which detailed studies about sediment transfer in the lower Ebro in the 2000s earth processes have been traditionally received by social scientists and several persons involved in the creation of the Ebro Delta Natural (Clark & Yusoff, 2017). Among such processes, the sediment cycle is Park during the 1970s and 1980s (Aguettaz-Vilchez, 2020). These in­ increasingly approached from a material perspective emphasizing terviews also opened the door to reports produced for the Catalan or physical properties and dynamics of sediment seen as enabling, con­ Spanish administration, conserved by the interviewees or at specific straining, or simply moving along social and political action (Bremner, public libraries such as that of the Institut Cartogràfic de Catalunya. 2020, 2021; Clark & Yusoff, 2017). Sediments may be used to accom­ The article is structured as follows. First, we situate and discuss the plish certain specific social and political goals at each stage of the convergence of interests on sediments at the intersection of natural and sediment cycle (Bremner, 2020). For example, sand imported from social sciences, more specifically political ecology and critical ap­ Cambodia and used for land reclamation in Singapore expands the na­ proaches to physical geography. In this context, we delve into the tional “territory” in this city-state (Beiser, 2018; Jamieson, 2021). concept of sedimentary justice (Dawson, 2021a) and its connections to However, sediment may also disrupt those goals (Bremner, 2020). The political ecology and water justice. After this section, we adopt a his­ agency of sediment appears in issues ranging from the transformation of torical narrative to show how the politicisation of sediment scarcity in Rhône and Mississippi deltas (Duperrex, 2019) to the changing land­ the Ebro unfolded during the last half century, from the construction of scapes of riverine islands in the lower Ganges (Lahiri-Dutt, 2014; the large reservoirs that disrupted sedimentary fluxes in the 1960s to the Mukherjee & Lahiri-Dutt, 2021), and to intervening in the class and launch of the Campaign for Sediments. In this narrative we pay special gender divides in North Bihar, India (Cortesi, 2018). In all these con­ attention to how different actors mobilised the importance of tributions, social scientists including political geographers (Hommes non-human forces influencing sedimentary fluxes in the Holocene and et al., 2022), are willing to explore routes towards the hybridization of their role in the origins of the Ebro delta. This vision challenges the the social with the material breaking up land and water, and nature and notion that the delta was the direct result of human activity in the Ebro society binaries. basin; highlights the important role of non-human processes in the A similar path towards hybridization seems to be pursued in the case production of sediments but, most importantly, points to the manage­ of the natural sciences and especially in critical physical geography ment of the reservoirs built during the 1960s as the main responsible of which emerged as both a reaction to the progressively dominant position current sediment scarcity in the delta. of the social sciences in new socionatural disciplines such as political ecology and as an interest in exploring the relationships between 3 S. Gorostiza et al. Political Geography 107 (2023) 102975 biophysical and social systems (Lave et al., 2018). In the case of sedi­ and resource change over time, as well as by interrogating scientific ments, this interest arises from increasing human interferences in the interpretations of river geomorphology and delta development and the sediment cycle. The construction of large dams in many river courses role of human and non-human forces in these. In sum, the concept of throughout the world has caused a drastic reduction in sediment sedimentary justice may provide a more encompassing approach to the transport reaching deltas and other low lying coastal areas (Syvitski complexity of fluvial systems that is somewhat constrained by the et al., 2005, 2022; Vörösmarty et al., 2003). However, the low sedi­ concept of water justice and its emphasis on the liquid component of mentary loads observed in some Mediterranean rivers are also related to rivers. Likewise, sedimentary justice would relate better to new de­ deep socioeconomic changes in the wider catchment geographies velopments in environmental justice in providing a wider field of theory conducive to decreases in sediment production (Dufour et al., 2017; and practice for incorporating the non-human world (Schlosberg, 2013). Scorpio & Piégay, 2021). Moreover, the increasing extraction and con­ While the notion of sedimentary justice (Dawson, 2021a) has not sumption of sediment by human activities, most notably sand for con­ been drawn on widely, several recent studies explore the overlap be­ struction, beach reposition and land conservation, and advanced tween sediment politics and questions of justice. For instance, the Far­ industrial uses, implies a deep reconfiguration of sediment fluxes in akka Barrage Project in the lower Ganges has modified riverine which economic interests join natural processes as key driving forces sedimentation patterns and, among other impacts, this has changed the (Syvitsky & Kettner 2011; Beiser, 2018). Both from the social sciences dynamics of formation and dissolution of river islands —known as chars. and from the natural sciences there is a growing recognition of the need In consequence, the vulnerable char dwellers have been repeatedly of overcoming the nature-society divide and work towards more hy­ forced to resettle, with a lack of responsiveness from the authorities (De bridized scientific approaches in the line of the planetary social science Micheaux et al., 2018; Mukherjee & Lahiri-Dutt, 2021). In the lower advocated by Clark and Szerszynski (2020) but also attentive to social Mississippi River, the local African American community has opposed a and environmental justice (Lave et al., 2018). river diversion project aimed at directing sediment-rich flows to protect Incorporating both perspectives helps to produce more nuanced ex­ coastal areas on the grounds that it reinforces a history of racial in­ planations of the interplay between the material and the social. For equalities connected to coastal engineering (Barra, 2021). In the Rhône example, in the Mediterranean, the increase in sedimentary territories River, fishers, environmentalists, and local communities have com­ found in the final stretches of rivers has been attributed to human plained about dam flushing operations to restore sediment transport, induced erosion in the mountainous upper catchments since Roman due to their impact in spreading pollutants and affecting the local fauna times (Maselli & Trincardi, 2013). However, longer geological records (Guerrin et al., 2021). Last, but not least, the importance of restoring reveal periods of relatively frequent large floods with abundant pro­ sediment transfer is one of the scientific arguments mobilised —and duction and transportation of sediment as well (Cearreta et al., 2016). disputed— in the often-controversial projects for dam removal (Dufour Likewise, decreasing sediment fluxes in rivers today could be attributed et al., 2017). to declining rainfall but also to land use changes, for example affores­ As these cases suggest, the disruption of sedimentary fluxes caused tation processes following the collapse of traditional mountain econo­ by dams and the uses of sediment for river and coastal restoration offer a mies that reduce erosion and the capacity for the mobilisation of fertile avenue for studies of sedimentary justice. A case in point is the sediment. These two scenarios are present in the case of the Ebro basin gradual but continuous deposition of sediments in reservoirs (Syvitski and delta, setting the scene for different interpretations regarding et al., 2022), known as reservoir silting or reservoir sedimentation. As a human and non-human factors explaining the fluctuations of sedimen­ result of the accumulation of water in reservoirs, the substances sus­ tary fluxes and the evolution of deltaic morphologies. At any rate, the pended and dissolved in the turbid flows of rivers tend to settle to the interplay between material, social and political agencies in the different bottom, slowly reducing its storage capacity (Schleiss et al., 2016). stages of the sediment cycle helps to understand why between 1950 and However, beyond the natural deposition of solids in reservoirs, the 2010 human activities at the global scale have simultaneously boosted immobilization of sediments is favoured by specific uses of stored river river sedimentary fluxes by 215 percent and reduced the amount of flows. Sediment in flowing waters is considered an obstacle for hydro­ sediment reaching the oceans by 49 percent, with reservoirs largely power plants, due to the abrasion it causes in hydraulic machinery such contributing to the latter figure by immobilizing sedimentary fluxes as turbines and their cooling circuits (Arora et al., 2022; Schleiss et al., (Syvitski et al., 2005, 2022). 2016). Therefore, water uses for hydroelectric production favour the The convergence between the material turn in social sciences and the immobilization of sediment in reservoirs, upholding “clean” water and recognition of human agency in interfering with Earth cycles by natural strengthening the land/water separation. The fact that the storage vol­ scientists has profound social and political implications which, in the ume of reservoirs continues to be described as water despite the gradual case of sediments, can be best unearthed by hybrid concepts such as reduction caused by sediments illustrates how “[t]he perspectives of “sedimentary justice” (Dawson, 2021a). Dawson conceives sedimentary dominant actors and available data often promote a view of river waters justice as “a lens through which to excavate the layered politics of ac­ as a liquid resource only” (De Micheaux et al., 2018: 644). Most cess, rights, and security of sediment” and mostly focuses on the spec­ importantly, while sediment accumulates in river reservoirs, the tacular expansion of sand extraction and trade (2021a). This notion resulting reduction of sedimentary fluxes downstream contributes to connects to efforts towards the geologization of political ecology land subsidence and coastal erosion in deltas and other low lying coastal (Dawson, 2021b), in line with Clark and Yusoff’s calls for a “politi­ areas (Syvitski et al., 2009). Together with climate change this has cisation of the geologic” and a “geologization of the political” (2017:17). multiplied what Dawson (2021a) calls “sedimentary insecurity” for While Dawson (2021a) does not relate sedimentary justice to the liter­ humans and ecosystems present in these areas. ature on water justice nor political ecology of water, there is ample space Finally, sedimentary justice acknowledges the importance of both to do this in light of recent work that discusses water justice as histori­ sediment quantity and quality (Dawson, 2021a). Due to the long-time cally rooted and contingent, while underlining its relational and scales involved both in the alteration of sediment fluxes and the multi-scalar character (Perreault et al., 2018). However, the literatures power relations embedded in them, this perspective requires a historical on water justice and political ecology of water have so far paid little approach (Parrinello & Kondolf, 2021). Moreover, the immobilization of attention to sediment. sediment in reservoirs can also fix toxic substances which remain a In this regard, the lens of sedimentary justice can contribute to De hazard decades after they were deposited, potentially reemerging in the Micheaux, Mukherjee and Kull’s proposition of “a materially enriched future (SedNet, 2004; see also Guerrin et al., 2021). Last, but not least, a hydrosocial cycle” (2018:645) that takes sediment into account, by historical approach can also enlighten the changing perceptions of analysing power relations embedded in water and sediment-related sediments from nuisances to resources as they evolve together with governance; scrutinizing how understandings of sediment as nuisance human societies becoming imbued with social and political matters 4 S. Gorostiza et al. Political Geography 107 (2023) 102975 (Bridge, 2009; Guerrin et al., 2021). However, history needs to tran­ brought vast quantities of sediment to the Ebro tributaries, its main stem scend the purely human past and embrace longer term, geological per­ and, finally, to the delta plain (Bayerri, 1935; Deffontaines, 1951; spectives as well (Chakrabarti, 2019). Kleinpenning, 1969; Pena, 1964). Kleinpenning’s account summarises the conception of the delta as a 3. Dam building and the disruption of sedimentary fluxes relatively recent formation resulting from human activities in the river basin. However, around the same time, another researcher who was In 1955, the Instituto Nacional de Industria (National Institute of carrying out a PhD thesis on the geological origins of the delta came up Industry) commissioned the construction of two large dams as part of the with a different view. Unlike accounts that focused on the recent history plan to expand hydropower in the Ebro basin. The construction of of the delta’s surface and emphasised the role of humans in the forma­ Mequinenza and Ribarroja reservoirs on the lower Ebro, with storage tion of the delta, geologist Andrés Maldonado adopted a longer time capacities of 1534 hm3 and 207 hm3 respectively, dwarfed in size the scale involving non-human forces. He argued that similarly to other reservoir of Flix, completed in 1948 (11,4 hm3). When they started large deltas, the deposits on the Ebro delta’s base had their origins in the operating in the late 1960s, Mequinenza and Ribarroja represented a end of the last glacial period, when sea level rise submerged the major step of the hydraulic modernization project of the Francoist “primitive delta plains” —as Maldonado referred to them. Using carbon- dictatorship (Swyngedouw, 2015). Built on the main stem of the river 14 dating technology, Maldonado concluded that the basis of the delta and with a large capacity, they became a barrier for sediments as soon as started accumulating around 13.000 years before present (Maldonado, they were erected, reducing bedload sediment transport to the delta by 1977; Solé Sabarís et al., 1965). Along with this new understanding on 95% (Vericat & Batalla, 2006). At the time, however, engineers did not the delta’s origins, Maldonado stated that the emergent part of the delta consider the potential impact of the interruption of sediment fluxes on had been prograding significantly between the 17th and 19th centuries. delta sedimentation.1 This has a parallel with the Po River in Italy, In other words, the delta surface had changed significantly in the last where the construction of Isola Serafini Dam did not trigger concerns five centuries, but its origins went back thousands of years (Maldonado, about downstream impacts of the reduction of sedimentary fluxes when 1977). it was being built (Parrinello et al., 2021). During these very same years the claims that the Ebro delta had This is partly explained by the prevailing ideas about sediment excess stopped growing reached the general public. Ramon Folch, a leading in river waters, widely established by the mid-20th century. The inces­ scientist at the Institució Catalana d’Història Natural (ICHN), observed sant progradation of deltas was taken for granted. In the Ebro, writing in that the delta had ceased its progradation of 10 m per year, which he 1936, British geographer E.H.G. Dobby stated that the delta had pro­ attributed to construction of the reservoirs, and warned that the coast­ gradated near 50 m in the 20th century. Dobby left a rich testimony of line had started to retreat (Folch, 1976). At the time, however, the Ebro the Ebro delta landscape, with references to the uses of sediment in delta faced more urgent threats than a decrease in the sediment load of agriculture but also to the nuisances it caused. He observed how deposits the river. From large state-sponsored plans for agricultural drainage to by regular annual floods had reduced the effective heights of old houses’ urbanization projects for touristic uses and inter-basin water transfers, doors, estimating an increase of 50 cm along the riverbanks since 1900. several development projects threatened the delta’s ecological value and Moreover, sediments silted irrigation canals, requiring regular cleaning the highly diverse waterfowl population (Folch, 1976). It was the con­ (Dobby, 1936). The abundance of sediment hindered river navigation, cerns over the ecological value of the delta’s wetlands what eventually as engineers working at the river basin authority (Confederación sparked the creation of a protected area in 1983, when the Catalan Hidrográfica del Ebro) highlighted immediately after the Spanish Civil government approved the creation of the Ebro Delta Natural Park. This War.2 They argued that the solid matter transported by the Ebro was regional park ensured the protection of several wetlands of ecological higher than in any other European river with a similar gradient and value but left ample space for agriculture and human activities pointed at the “quick growth of the delta” as a proof of the abundance of (Aguettaz-Vilchez, 2020). However, it did not influence river manage­ sediment. ment, as the Catalan government had no legal power to regulate the This situation changed when the impact of the dam construction Ebro River flows or to protect the delta’s coast; both were and remain started to be felt. In the late 1960s, Dutch geographer J.G.M. Klein­ competences of the Spanish state, through the corresponding ministries penning pointed out that the delta was still growing, although at a much and the river basin authority. The first proposals to mobilise the sedi­ slower rate. Less sediment was reaching the river mouth, he argued, for ments trapped in the Ebro’s reservoirs emerged during the following two reasons: first, the barrier effect of large dams, and second, the years, in the context of the scientific criticisms of large inter-basin water ongoing reafforestation of the basin (Kleinpenning, 1969). In other diversions sponsored by the state. Along with these, the arguments words, most of the solid matter transported by the river was captured in supporting the non-human origins of the delta gained new force. the dams, but reafforestation was also reducing erosion and therefore decreasing the amount of sediment that ended up in rivers. Citing the 4. Less water equals less sediment. Challenging interbasin water work of local historians and geographers, Kleinpenning considered that transfers the formation of the delta was “a recent phenomenon” in geological terms. According to this account, in the 6th century B.C. the city of During the early 1990s, a state-sponsored draft for a National Hy­ Tortosa was still a port, while by the time of the Roman occupation the drological Plan (NHP, Plan Hidrológico Nacional) envisaged that more town of Amposta was still by the sea. Only in the 14th and 15th cen­ than 1000 hm3 per year should be diverted from the Ebro to Eastern and turies, he argued, did the delta start growing rapidly, when the South-eastern Spain and to Barcelona (Swyngedouw, 2015). Scientists increasing rates of deforestation in the basin led to erosive processes that and environmentalists criticised these plans for their lack of attention to environmental impacts and a widespread social mobilisation against diversion projects formed in the Ebro River basin (Arrojo & Gracia, 1 2000; Ibáñez et al., 1999). A key claim of the local governments in the We have found no discussion on the impact of reservoirs in sedimentary Ebro delta was that water transfers could worsen coastal regression, fluxes in the projects of Mequinenza (1957) and Ribarroja (1958), nor in the "Plan de aprovechamiento del tramo del río Ebro entre Escatrón y Flix" (1956), which they related to the lower fluxes of sediment connected to all of them kept at the Archivo de la Confederación Hidrográfica del Ebro. decreasing river water flows (La Vanguardia, 1985, 1990b).3 Despite 2 See ‘Referencia No6099. Informe sobre la navegación por el río Ebro’ (1940, p. 181) authored by José Bravo Suárez and José Cruz-López Larrañaga; Min­ 3 isterio de Obras Públicas and Confederación Hidrográfica del Ebro. Archivo de Letter from the Mayor of Sant Carles de la Ràpita to the Diputació de Tar­ la Confederación Hidrográfica del Ebro. ragona, 5 December 1980. Arxius de la Diputació de Tarragona, box 991, 16B. 5 S. Gorostiza et al. Political Geography 107 (2023) 102975 calls for calm by politicians who downplayed this possibility (La Van­ movements, non-governmental organisations, and scientists critical of guardia, 1990a), several storms affecting the Ebro delta in 1990 the NHP. Among the organisations forming the PDE there were several heightened these concerns. The southern bar of the delta (El Trabuca­ groups that had been active in the Ebro River basin throughout the dor) broke in October 1990, leaving one of the delta’s spits surrounded 1990s and before, when they rejected inter-basin water transfers and by water for months (La Vanguardia, 1990c). During the following large hydraulic works, focusing instead on managing water demands years, several projects studied the best means to prevent the regression and promoting efficiency, desalination, and reutilisation policies of the delta. The reports commissioned by the Irrigation Communities (Tàbara & Ilhan, 2008). Several relevant scientists critical of the NHP proposed building hard defenses and pumping sand artificially to protect —such as Carles Ibáñez, Narcís Prat or Pedro Arrojo— participated the delta (La Vanguardia, 1992).4 actively in the PDE. As an alternative to this infrastructural approach, the idea of mobi­ From the preservation of wetlands and the life of birds to the pro­ lising the sediment trapped in the large reservoirs of the lower Ebro tection of local livelihoods and the fate of river sediments, the PDE started taking shape in scientific circles. In 1994, geologist Antoni mobilised a diverse set of human and non-human concerns in its criti­ Canicio and biologist Carles Ibáñez delivered a report to the Catalan cism of the NHP (Swyngedouw, 2015). The idea that further water di­ administration in which they pointed at the scarcity of sediment in the versions from the Ebro would endanger the river delta was one of the lower Ebro River as the main cause of the delta’s degradation. This was central claims. Diminishing water flows would have negative effects on the result, they argued, of a hydrologic planning model that did not take the delta’s hydrology and ecology, worsening problems of eutrophica­ into consideration that rivers carried solid matter, not only water. The tion and salinization. It is in connection with these arguments that the drastic reduction of sediment reaching the delta after the construction of decrease of sedimentary fluxes was brought to the fore. One of the most hydropower plants in the main stem of the river constituted “a severe prominent scientists critical of the plan, Pedro Arrojo, argued that aggression to the deltaic environment” (Canicio & Ibáñez, 1994, p. 80). further water transfers would also reduce the already scarce sedimen­ To alter this process, they advised to establish a sediment management tary fluxes and worsen both delta subsidence and coastal erosion pro­ plan including measures to by-pass sediments immobilized in Mequi­ cesses. Citing the research of Carles Ibáñez and other scientists (Ibáñez nenza and Ribarroja reservoirs. Otherwise, they argued, the coastline et al., 1997, 1999), Arrojo pointed out that larger river flows and would continue being eroded and the delta plain would keep sinking. regulated floods were needed to maintain the ecological value of the This and other studies by the same authors emphasised the risks caused delta and called to consider “new techniques of sediment management” by the subsidence of the delta plain, which could be aggravated by sea (Arrojo & Gracia, 2000, p. 12). In contrast to this vision, the level rise associated with climate change. Flushing sediments from the state-sponsored studies of the NHP impacts regarded the effects of the dams thus increasing solid matter reaching the delta was portrayed as a massive water transfers projected for sediment transport as “practically sustainable solution to counter this process which deserved to be studied negligible” and therefore did not include any compensatory action in detail (Canicio & Ibáñez, 1994; Ibáñez et al., 1997; Ibáñez et al., (Centro de Estudios Hidrográficos, 2000, p. 54). 1996). Despite the significant social opposition to the NHP in the Ebro basin, These arguments about the value of sediments and the causes of its the Spanish conservative party approved the plan in 2001. In this scarcity in the river’s mouth came accompanied with research that for context, since one third of the funds required for it depended on the EU the first time forcefully emphasised the non-human origins of the Ebro contribution, the PDE focused their efforts on convincing European delta development. Following research discussing the early origins of authorities about the negative environmental and socioeconomic im­ world deltas and using radiocarbon dating techniques (Stanley & Warne, pacts of the plan (Tàbara & Ilhan, 2008). To do so, they put upfront the 1994), Canicio and Ibáñez (1999) built on the work of Maldonado endangerment of the delta ecosystems and the importance of taking (1977) and challenged authors (e.g. Guillén & Palanques, 1997) who sediments into account when calculating the minimal river flows portrayed the Ebro delta as the result of a quick development during the required to sustain their mobilisation (Ibáñez & Prat, 2003; Arrojo medieval period, mostly related to human intervention in the river basin Agudo, 2003). Coinciding with these efforts, several storms affecting the (deforestation and agricultural development). Not only did they criticise Catalan coast brought again under the spotlight the degradation of the the inattentive use of historical sources (Ibáñez et al., 1996) but also Ebro delta (La Vanguardia, 2002a). questioned interpretations of historical accounts that described the city The symbol of the Platform in Defence of the Ebro River —a knotted of Tortosa as a seaport in Roman times (Bayerri, 1935; Serra Reventós, pipe— and the blue colour of their iconic t-shirts make evident the focus 1997), objecting to them for a lack of scientific basis. Instead, using on water in the opposition to inter-basin transfers during the 1990s and carbon-14 techniques, they dated parts of the delta going back 5745 early 2000s. However, the scarcity of sediments was implicit in the years before present (Canicio & Ibáñez, 1999). These analyses brought movement demands for larger river flows and explicit in the arguments the Ebro delta case in line with other Holocene deltas that originated about the value of sediments to compensate for the delta’s subsidence. In after the last sea level rise (Stanley & Warne, 1994). fact, in 2002 the PDE already protested the immobilization of sediments Despite the recommendations to consider sediment management in reservoirs by removing a symbolic quantity of sediments from policies, neither the Catalan government nor the river basin authority Mequinenza and pouring them in the delta (La Vanguardia, 2002b). explored these possibilities at the time. After the victory of the conser­ During the first decades of the 21st century, as the impacts of climate vative party in the 1996 Spanish elections, public discussion about the change became increasingly manifest, the claim for more sediment Ebro delta’s future was increasingly marked by the re-emergence of reaching the delta became the foundation of a campaign launched by water diversion plans from the Ebro as part of a new National Hydro­ several organisations in the lower Ebro River. logical Plan (NHP). The conservative government announced the project in the year 2000, involving (again) the diversion of more than 1000 hm3 5. Campaigning for more sediments per year from the Ebro to the South-eastern regions as well as to Bar­ celona (Swyngedouw, 2015). In response, the so-called Platform in In early 2004, the Directorate-General for the Environment of the Defence of the Ebro (PDE) was launched, bringing together social European Commission advised against the EU funding of the Ebro water diversion. Their report —leaked to the press— included some of the arguments advanced by the PDE, pointing to the ecological impact that 4 Comunidad General de Regantes del Canal de la Derecha del Ebro, and the reduced river flows could have in the delta as one of the reasons Iberinsa. 1992. ‘0479A Estudio de la Regresión del Delta del Ebro y Propuesta against funding the project (La Vanguardia, 2004a, 2004b; Tàbara & de Alternativas de Actuación’. Archivo de la Oficina de Planificación Ilhan, 2008). Without the EU support, the fate of the NHP was sealed, Hidrológica (CHE). and the unexpected socialist victory at the 2004 Spanish elections 6 S. Gorostiza et al. Political Geography 107 (2023) 102975 confirmed its demise. One of the first measures taken by the new gov­ associations, together with scientists and local population (Bertomeu, ernment was to cancel water diversions and propose the building of 2010; Ebre.net, 2015; Segarra, 2018, 2020; Tinet.cat, 2008).7 desalination plants instead (Swyngedouw, 2015). From its onset, the Campaign has made sediments visible in perfor­ However, the interest among scientists involved in the PDE in the mative ways —pouring sands and gravel in front of official buildings mobilisation of sediments and the possibility of using part of the funding during protests or carrying them during demonstrations. At a march in already promised by the EU led to the first studies that examined the Barcelona against the water policies of the Spanish government, the feasibility of sediment transfers from reservoirs to the delta. In 2004, at members of the Campaign for Sediments carried a wheelbarrow full of the request of the Catalan Water Authority and the Fundación por la sand and silt, showing a sign that read the names of the main dams of the Nueva Cultura del Agua, engineer Juan Pedro Martín-Vide prepared an Ebro River, along with the sentence “sediments are here”. The centrality economic, technical, and environmental assessment on the sources of of sediment is illustrated by the Campaign’s t-shirts, coloured brown sediment in the lower Ebro and the available techniques to transport it to —in contrast to the distinctive blue of the PDE protests— as well as the the delta. Martín-Vide concluded that flushing sediments from the depiction of the Ebro’s large reservoirs on maps as patches of mud.8 The Ribarroja reservoir was the least costly measure to restore sedimentary Campaign’s mottos and banners at protests encapsulate the idea that fluxes to the lower Ebro and alleviate the delta’s subsidence. Even if water transfers aggravate sediment scarcity (“We want sediments, no to Martín-Vide considered that the benefits of restoring sediment supply to water transfers”) and that both river flows and sediment fluxes are key the delta would be apparent only after decades, he believed that these for the delta’s future (“The Ebro without flows = the end of the delta”).9 policies could avoid much more costly interventions in the future Overall, rather than arguing for dam removal, the Campaign defends the (Martín-Vide, 2004). feasibility of sediment transfers and management policies, referring to Less than two months after Martín-Vide delivered his report in 2004, international experiences and to scientific literature that supports its a major scandal involving pollutants immobilized in the sediments of application to the Ebro River (see, among other, Rovira & Ibáñez, 2007 Flix reservoir —located downstream of Ribarroja— hit the news (La or Kondolf et al., 2014, both cited in Segarra, 2020). Vanguardia, 2004b). According to a scientific study requested by the Together with the mobilisation of sediments trapped in reservoirs, to Catalan government —and again leaked to the press—, near 700.000 address the “sedimentary insecurity” (Dawson, 2021a) produced in the tonnes of sediments contaminated with organochlorides, mercury, delta, the Campaign for Sediments has argued for an increase of Ebro heavy metals and radioactive isotopes filled the reservoir. The pollution water flows to guarantee the river’s capacity for sediment transport and was the result of the activity of the electrochemical industry located in to sustain estuarine ecosystems. Setting river environmental flows —an Flix, established in 1897. While initially the pollutants were washed obligation under European legislation— is a prerogative of the river away periodically by seasonal floods, once the reservoir was completed basin authority, which in 2014 set this value for the Ebro at 3370 in 1948, they started accumulating in its bottom, mixing with sediments hm3/year, less than half the value demanded by the authorities of the (Pujadas i Garriga, 2015). According to Martín-Vide this news seriously Catalan government and environmental organisations. The river basin hindered public debates about sediment transfer.5 The long and con­ authority considered that the modification of environmental flows voluted cleaning process that followed —today at its final stages, with caused by hydroelectrical activity did not affect the functioning of the costs larger than 200 million euros— was covered almost completely Ebro (Zografos, 2017). In this regard, the Campaign for Sediments has with public funds, as the courts ruled that the company could not be been particularly active in denouncing corporate hydropower interests charged with the historical liability of the pollution load (Pujadas i for prioritising the production of electricity at the expense of sediment Garriga, 2015). management needed to ensure the delta’s future (Segarra, 2020). Martín-Vide’s team went on to complete a detailed proposal for The non-human origins of the Ebro delta play an important role in flushing sediment from Ribarroja (Roca & Martín-Vide, 2005). Howev­ the Campaign’s politicisation of sediment scarcity. In the account of the er, such scheme required drawing down the reservoir periodically Campaign for Sediments, it is not only the origin of the current delta in —therefore disrupting hydropower production— and was received the Holocene that is underlined, but the action of the sediment carried coldly by the private company managing the dam. The river basin au­ by the river during the last few millions of years (Segarra, 2020, p. 32). thority was also sceptical about the feasibility of releasing sediment, The present-day delta is presented as originated in the Holocene, claiming, among other reasons, that the nuclear power plant located approximately 6000 years before present, but the continued action of downstream of the dam should be taken offline every time that sedi­ sediment fluxes and the existence of “other deltas” millions of years into ments were flushed from Ribarroja.6 To this day, both the concerns with the past is emphasised, echoing the accounts of Carles Ibáñez and other sediment quality in Mequinenza and Ribarroja and the nuclear power authors (Ibáñez et al., 1999, p. 37). Hand in hand with this portrayal of plant downstream Ribarroja remain among the main cautions invoked the delta comes a fierce critique of the “myths” that depict the delta’s by the river basin authority and the Spanish ministry in relation to the origin as a product of the deforestation of the Ebro River basin since the restoration of sedimentary fluxes (Centro de Estudios de Puertos y Roman, Medieval or the early Modern period. While it is conceded that Costas, 2021). deforestation increased the sedimentary transport during the last cen­ Parallel to these developments, local youth organisations of the delta turies, Segarra draws on research indicating that the main processes announced a “Day for Sediments” in 2008. Starting at a youth camp for shaping the delta’s morphology have been transport of sediments eroded the preservation of the southern delta’s sand bar, this meeting became a from the river basin for thousands of years. In other words, according to yearly event involving scientists studying the delta, like Antoni Canicio the spokesperson of the Campaign for Sediments, the delta is not or Carles Ibáñez. On several occasions from 2008 to 2015, the organisers “man-made”, and the arguments that sustain such origins “are interested of the “Day for Sediments” called for management policies that would in legitimizing the current management of reservoirs and downplaying restore sedimentary transport to the delta to balance both subsidence the importance of the Ebro delta” (Segarra, 2020, p. 42). and coastal retreat. Finally, in February 2015 they launched the Finally, the Campaign’s political mobilisation of history and geology Campaign for Sediments (“Campanya pels Sediments”) with the support of the PDE, green non-governmental organisations and ornithological 7 Interview with Josep Juan Segarra, spokesperson of the Campanya pels Sediments, 18 October 2021. 5 8 Interview with Juan Pedro Martín-Vide, 8 March 2022. Campanya pels Sediments, Facebook account, 17 September 2016. 6 Interview with Juan Pedro Martín-Vide, 8 March 2022. Retrieved on 21 September 2021. 9 Campanya pels Sediments, Facebook account, 5 June 2016. Retrieved on 21 September 2021. 7 S. Gorostiza et al. Political Geography 107 (2023) 102975 also engages with the role of sediment in the deltaic culture. The sediment quality relates to questions of justice (Dawson, 2021a). In portrayal of the sediments immobilized in reservoirs as a resource de­ addition, the long-lasting impact of the Flix scandal illustrates power­ velops hand in hand with the appreciation of past knowledge and uses of fully the capacity of sediments to “erupt into and disrupt human politics” sediment in the delta. “When turbid waters were flowing, my father used (Bremner, 2020, p. 1). The materiality of sediment —unlike that of to tell me: ‘this is gold’”, remembers one of the Campaign’s activists, water— can easily transcend history and bring the pollutants from the underlining the role that river flows had in the past to fertilise rice fields past to the present long after the activities that produced them ceased. In (Josep Bertomeu in Segarra, 2018, min 1, sec 18). The historical practice Flix, from the perspective of sedimentary justice, not only the costs of colmateo —the redistribution of sediment carried by the irrigation caused by private industry have been shifted to the public, but the canals in the rice fields— is mobilised as an example of a traditional possibilities of building alternative futures mobilising sediments for culture that kept the delta’s subsidence at bay before the large dams coastal restoration have been compromised. The pollution of Flix has were built on the Ebro and cut off the sediment supply (Rovira & Ibáñez, contributed to concerns about the quality of the sediments in Mequi­ 2007; Segarra, 2020). While the Campaign conceptualises sediment as a nenza and Ribarroja dams and the potential dangers of mobilising these blessing, it also acknowledges the need to study the quality of sediments sediments (Centro de Estudios de Puertos y Costas, 2021). deposited in Ribarroja and Mequinenza to ensure that they are not Third, a sedimentary justice lens makes visible the power relations polluted. However, it accuses the river basin authority of using this embedded in the separation between water and sediments taking place argument to postpone discussions about sediment mobilisation and in reservoirs. Building on scientific research and international practices portray it as dangerous and expensive (Segarra, 2020). of sediment management, the Campaign envisions an alternative man­ Overall, the proposals of the Campaign for Sediments to mobilise the agement of reservoirs that makes it possible to transfer immobilized sediment trapped in reservoirs and to increase river environmental flows sediments and facilitates sediment transport by increasing river envi­ come in contrast with the policies implemented by the Spanish envi­ ronmental flows. But this proposal disrupts hydropower interests, as it ronment ministry, which has focused on intervening in the coastline. involves a different use for the water stored in reservoirs than the pro­ During the last years, the state has started buying out (or expropriating) duction of electricity (and of economic benefit). The production of land in the delta coastline in order to transform it into natural buffers electricity favours the accumulation of water and the use of “clean” H20 that absorb the effects of sea-storms, de facto applying a strategy of in turbines, therefore contributing to the deposition of sediment. On this climate change adaptation (Reuters, 2021; Zografos, 2017). More basis, the Campaign for Sediments argues that the production of sedi­ recently, state authorities have agreed on the mobilisation of vast mentary scarcity and insecurity in the delta is part and parcel of a spe­ quantities of sand deposits submerged in the delta as a temporary so­ cific way of managing reservoirs that prioritises the interests of lution to reinforce the coastline. But these also come at high costs and hydropower corporations. uncertainties regarding safe futures (Catalunya Diari, 2021; Segarra, Fourth, the non-human forces shaping the origins and development 2020). of the delta are key in the arguments of the activists and scientists that demand the restoration of sedimentary fluxes. In arguing for the non- 6. Conclusions human origins of the delta, the Campaign mobilises the geological past in claims for sedimentary justice, highlighting the importance of Through the lens of sedimentary justice (Dawson, 2021a), this paper sedimentary fluxes without human intervention and hence pointing at has examined the politics of sediment scarcity in the lower Ebro River the building of reservoirs and the immobilization of sediment as the and traced the emergence of the social demand for more sediment to geological scale turning point that marked the production of “sedi­ counter delta subsidence, sea level rise and coastal erosion. These mentary insecurity” (Dawson, 2021a) in the delta (Campanya pels gradual processes of degradation seemed a distant risk in the 1970s, Sediments, 2020; Segarra, 2020). when development projects began to directly threaten the delta’s Finally, as shown by the Gloria storm, the impact of extreme clima­ ecological value. However, throughout the 1990s and 2000s, the social tological events during the last decades has made more visible the mobilisation against water diversion schemes and the impacts of climate human vulnerability associated to sedimentary insecurity. While change in the delta brought renewed attention to the immobilization of perhaps ephemeral in the media, the storms of 1990 and 2002 urged sediment in reservoirs and the resulting “sedimentary insecurity” public debate, research and policy proposals about the delta’s future. (Dawson, 2021a) produced in the lower Ebro River. What remains to be seen is if the devastation caused by Gloria will mark As a sediment-centric perspective (Parrinello & Kondolf, 2021), the a turning point in the politics of sedimentary management in the Ebro lens of sedimentary justice can address the insufficient attention given to River basin and the protection of the delta. As the degradation of deltaic sediment in political ecology and water justice studies and contribute to environments around the world worsens, the Campaign for Sediments a “materially enriched hydrosocial cycle” (De Micheaux et al., may be one of the first examples of social mobilisation politicising 2018:645). The perspective of sedimentary justice opens new avenues to sediment scarcity and demanding more sediment for the preservation of incorporate the non-human world, enriching the literature on environ­ deltaic environments, their population, and livelihoods. But it may not mental and water justice (Boelens et al., 2018; Schlosberg, 2013). In be the last. particular, the historical perspective allows for visibilising the agency of the non-human world in the politicisation of sediment scarcity. We Declaration of competing interest highlight the relevance of sedimentary justice for the Ebro River case in the following points. The authors declare that they have no known competing financial First, key to claims of sedimentary justice, activists and scientists interests or personal relationships that could have appeared to influence defending the restoration of sedimentary fluxes portray the sediments the work reported in this paper. immobilized in reservoirs as a valuable resource. A sedimentary justice perspective may involve maximizing the resource dimension of sedi­ Acknowledgements ments and minimizing its hazardous potential for humans and non- humans. However, the restoration of sedimentary fluxes does not The authors wish to thank Mathias Kondolf for his comments on come without its own problems: sediment flushing from dams can create earlier versions of the manuscript. The authors gratefully acknowledge nuisances and be contested by local and environmentalist organisations support from an Émergence(s) grant from the City of Paris for the project as well (see for instance Guerrin et al., 2021). “Shifting Shores: An Environmental History of Morphological Changes Second and along these lines, the pollution of the sediments immo­ in Mediterranean River Deltas in the Twentieth Century”. Santiago bilized in the reservoir of Flix shows how not only quantity, but Gorostiza’s work was supported by the EU-Next Generation and 8 S. Gorostiza et al. Political Geography 107 (2023) 102975 Ministerio de Universidades de España (Maria Zambrano grant 2022). Clark, N., & Szerszynski, B. (2020). 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