Here’s my go at interpreting with a “geologic” eye:
The waters that are so deep blue are coming from the Baltoro Glacier of the world’s second highest mountain, K2. The blue color is characteristic of the pure melt water of glacial streams the world over. Where the river channels meet the slower moving waters, the green color of the water is a result of glacial rock flour in the water (finely ground rock material) which, by coincidence, has a particle size that refracts the green spectrum. The white areas of the delta appear to be cobbles of limestone and marble from the mountains nearby. The yellow? Hard call – looks like oxidation of soils forming on top of the carbonate cobbles (carbonate soils usually are red or deep orange) or the transport of such soils by the river system. But then -- could be vegetation. Beautiful, anyway!
This northern end of Pakistan is within the zone of continental collision of the “drifting” Indian subcontinent with the Eurasian Plate, with the result being the birth of the Himalayas.
This spectacular landscape was used with permission of its photographer, SM Buktari.
For more on the geologic wonders of Pakistan: