See footnote “i” to John 5:4, Revised Standard Version.
Today the Pool of Israel has been filled in and is a small public park dedicated to the Islamic philosopher Al-Ghazali. See U.C. von Wahlde, “The Nature and History of the Birkat Isra’il and Its Relation to the Pool ‘With the Expanse of the Sea’ (Sir 50:3): Rereading Charles Warren,” Palestine Exploration Quarterly 142, no. 3 (2010), pp. 159–181.
For this earlier explanation see M.-J. Pierre and J.-M. Rousée, “Sainte-Marie de la Probatique, état et orientation des recherches,” Proche-Orient Chrétien 31 (1981), pp. 23–42.
Shimon Gibson, “The Pool of Bethesda in Jerusalem and Jewish Purification Practices of the Second Temple Period” Proche-Orient-Chrétien 55 (2005), pp. 270–293. I, too, have written about the pool in “The Gospel of John and Archaeology” in James Charlesworth, ed., Jesus and Archaeology (Grand Rapids: Eerdmans, 2006), pp. 523–586, and later in “The Pool(s) of Bethesda and the Healing in John 5: A Reappraisal of Research and of the Johannine Text,” Revue Biblique 116, no. 1 (2009), pp. 111–136.
This channel extended southward toward the Temple Mount. Archaeologists have been able to explore this channel only for about 50 yards before reaching blockage, so its precise destination cannot be determined.
Mishnah, Mikva’ot 6.8.
Tractate Shabbat 13b. See von Wahlde, “The Nature and History of the Birkat Isra’il and Its Relation to the Pool,” pp. 159–181.