According to a 1989 report (and an earlier one) on Tell el-Hesi, the bricks of that time period showed evidence of a wetter climate, with perhaps the Wadi Hesi flowing year-round. While this is somewhat unlikely, the Dead Sea being only slightly higher in the EB than it was c. 1890, it is plausible that wadis, being less silted up, might have had more water flowing through them in earlier periods, the coastline having more wadi mouths than would be possible today (Tell Abu Hawam, anyone?).