After 12 months of traversing the desolate sand  covering the northern Sinai Peninsula, these two Light Horsemen have just arrived at one of the large oases near El Arish, a port on the Mediterranean coast by the delta of the Wadi El Arish. The riders are allowing their delighted horses to splash in the shallow water on their way to the camp just outside the town of El Arish.
This was how Ion Idriess described his experience in his diary as recorded in his book THE DESERT COLUMN:

"February 10th [1917] - A whopper oasis close by the beach. The minaret of El Arish is about three miles away. How strange it is , the old sea battering the desert shore,...Our horses don't know what to make of the sea...' p175

"February 12th [1917] - El Arish is a string of large oases about seven miles long, most oases hug the shore. A sombre sandhill by the sea is topped by the domed tomb of Nebi Yesir. By a beautiful grove of palms is the spreading mouth of the wadi, once famous as the "River of Egypt". It only runs with brown water when storms burst on the distant hills. Encircling these  oases are bare sandhills. In the centre of the oases is land cultivated exactly as it was in the days of the Pharaohs." p175

"....thousands of horses are rollicking on the shore" p176
['THE DESERT COLUMN', Ion Idriess]