فَتَوَسَّطَا عُرْضَ السَّرِيِّ وَصَدَّعَا ۞ مَسْجُورَةً مُتَجَاوِرًا قَلَّامُهَا
They reached the middle of a narrow watercourse and entered a water-filled place bordered by closely growing qallām plants.
Al-sariyy denotes a small stream or channel. Masjūrah refers to a place filled with water, and qallām to vegetation growing nearby. The earlier prolonged thirst now meets its narrative answer as the animals arrive at water.