Complex sentence: The campaign to prevent the lake from being raised involved politicians and senior bureaucrats, and succeeded in modifying the original plans, permitting the construction of the power station, but preventing it from operating to the full degree that had originally been intended.
Split into simpler sentences: The campaign to prevent the lake from being raised involved politicians and senior bureaucrats and succeeded in modifying the original plans, permitting the construction of the power station. This also prevented it from operating to the full degree that had originally been intended.