## 1 Introduction  
Among the many threats to which archaeological sites are subjected in the Middle East and North Africa (MENA) region, dam constructions and artificial lake formations have been some of the most common over the last 50 years (Figure 1). During this time, hundreds of dams have been built in the Middle East, providing undeniable benefits but also having an impact at the socio-economic, environmental, and geopolitical level [1, 2, 3, 4] (pp. 13-14), [5] (pp. 4-6). Archaeological sites were also impacted by the construction of dams and subsequent formation of artificial lakes, a threat soon recognised by national and international institutions. Several salvage projects, consisting of archaeological surveys and rescue excavations, have been carried out in different regions where cultural heritage was endangered by the construction of dams [6, 7]. Some of the best known and best-published examples for Near Eastern archaeology are the salvage surveys and excavations carried out from the late 1960s until 2010-20112010s along the Euphrates and Tigris rivers (e.g., for the Euphrates, see refs [6; 7; 10; 11; 12; 13]. For the Tigris river see, e.g., refs [14; 15; 16; 17]) (Figure 2). However, two studies have pointed out that the general awareness of the potential loss of cultural heritage linked to dam construction has been less than optimal, even if archaeological survey projects were carried out in the past [18; 19; 20]. Using Turkey as a case study, [PERSON] et al. [19] describe how heritage protection still lacks a systematic approach to the safeguarding of archaeological sites and features, both pre- and post-flooding [19] (pp. 20-21), [21] (p. 13), [20] (pp. 30-32). Regarding the Euphrates, they point out that only 12 out of the 23 areas that would be affected by dams along the river have  
Figure 1: Location of active dams (higher than 15 m) and related reservoirs in the Near East and Egypt, data from the Global Reservoir and Dam Database (GRanD, last accessed 14 December 2020) [8; 9]. Figure 2: Archaeological Surveys parts of salvage projects in the Near East (personal adaptation and addition after [PERSON] et al., 2014). been surveyed before the formation of artificial lakes, and fewer than 20% (125) of the 650 flooded archaeological sites have been excavated [19] (pp. 21,22). It must be said, however, that even if a reservoir submerges and prevents access to an archaeological site, the destruction of the latter is not to be taken for granted. Sometimes following a submersion, archaeological features are buried beneath layers of deposits, and under specific conditions sites can emerge from the ebbing water, allowing rescue excavations to be carried out if promptly arranged [22] (p. 72). Something similar happened at the site of Kemune, which gained much attention from the public media not only for the archaeological and historical relevance of its findings, but also for the circumstances of its discovery. This site, submerged by the Mosul Dam reservoir (filled in 1986), was first discovered during a period of low water level in 2013 and then excavated by a Kurdish-German expedition in Autumn 2018 [23]. Another example of an archaeological site resurfacing from an artificial lake comes from the Haditha Dam reservoir. High-resolution (HR) images available in Bing Maps (most likely acquired in 2010-2011, Figure 2[24]) testify a similar phenomenon to that of Kemune. Part of the site of Kifrin, excavated in the late 1970s during the Haditha Dam salvage project [25; 26], was partially exposed. Thanks to the high resolution of the images available in Bing Maps, parts of the ramparts with the triple moat system and some internal buildings of the lower town were also still visible (Figure 3). After this brief overview, it is clear that there is evidence of a significant loss of archaeological data due to water submersion. However, we have evidence that some sites might be still accessible under specific conditions of receding waters.