English to Spanish Tech/Engineering Engineering (general) Dam spillway

Me encuentro con este término en el siguiente contexto:

Dam Spillway Protection
When a reservoir's designed top water level is reached, any additional water entering the reservoir must be allowed to flow downstream. In the majority of cases the water flows down a spillway and enters a natural watercourse. With the apparent increase in extreme rainfall events and with greater downstream developments leading to re-classification of dams, spillways often need to be upgraded to withstand greater discharge volumes.

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Desde ya, muchas gracias.