So, all dams need spillways to safely release  excess inflows and maintain the level of the reservoir once it's full.

因此，所有水坝都需要溢洪道来安全地释放多余的水流，并在水库满水后保持水位。

As the reservoir filled, it became clear to  operators that the spillway gates would need to be opened to release excess inflows.

当水库注满时，操作员清楚地意识到需要打开溢洪道闸门以释放多余的水流。