I’ve never heard of Hydro power boiling water. Usually hydro power is natural or pumped storage.

You’re just taking water from an upper reservoir and dropping it to a downstream river. Either a naturally-filled reservoir/lake, or a pumped storage reservoir where you use other cheap power during low usage periods to pump that water to a higher reservoir to utilize later. The pump doesn’t heat the water, it just moves it uphill to utilize later, like the Taum Sauk Hydroelectric Power Station in Missouri.