What happens to the stream and water table as the number of pumps running is increased.

The stream becomes narrow and the water table becomes shallow as the number of pumps running is increased.

Explanation:

More number of pumps clearly means more amount of water is extracted from the river. When the rate of refilling of the river is not as fast as that of emptying of the river, it is natural that the river would progress towards drying up. Before it dries up, the stream (the size or the span of flow) becomes narrow and the water goes deep to expose the riverbed.