What two activities attract animals to the desert pool of water and now humans?

That would be drinking and hunting.....

The animals from miles around came to drink from the little pools, and the wild sheep and the deer, the pumas and raccoons, and the mice all came to drink. And the birds which spent the day in the brushland came at night to the little pools that were like steps in the mountain cleft. Beside this tiny stream, wherever enough earth collected for root-hold, colonies of plants grew, wild grape and little palms, maidenhair fern, hibiscus, and tall pampas grass with feathery rods raised above the spike leaves. And in the pool lived frogs and water-skaters, and water-worms crawled on the bottom of the pool. Everything that loved water came to these few shallow places. The cats took their prey there, and strewed feathers and lapped water through their bloody teeth. The little pools were places of life because of the water, and places of killing because of the water, too.