Babylonian Talmud, Shabbat 26:71; Pliny, Natural History 5.12, 111.
See, for example, Josephus, Antiquities of the Jews 9.7 and The Jewish Wars 1.361; Pliny, Natural History 5.17.
Excavations at the site have verified the identification. Benjamin Mazar, Trude Dothan and Emanuel Dunayevsky, Ein Gedi: Archaeological Excavations 1961–62, Yediot 27 (1963) (in Hebrew).
F. M. Abel, Geographie de la Palesune II (Paris, 1938), p. 267; and Martin Noth, Das Buch Joshua (Tubingen, 1938), p. 72.
Roland de Vaux, Archaeology and the Dead Sea Scrolls (London, 1973), pp. 91–94. In this he followed Martin Noth. John Allegro, on the other hand, identified Qumran with Secacah, based on his reading of the Copper Scroll (The Treasure of the Copper Scroll [Garden City, NY: Doubleday, 1960], pp. 68–74, 144–145).
The sites they investigated—in the Wadi Buqe’ah—were Khirbet Abu-Tabaq, Khirbet es-Samrah and Khirbet el-Maqari. Frank M. Cross and J. F. Milik, “Explorations in the Judean Buqe’ah,” Bulletin of the American School of Oriental Research 142 (1956), pp. 5–17.
Khirbet Abu-Tabaq was identified with Middin, Khirbet es-Samrah with Secacah and Khirbet el-Maqari with Nibshan.
See the recent study by Tzipora Klein covering the past 200 years, “Morphological Evidence of Lake Level Changes, Western Shore of the Dead Sea,” Israel Journal of Earth Sciences 31 (1982), pp. 67–94.
Klein “Morphological Evidence.”
As noted in endnote 5, this was already suggested by John Allegro.