As a heatwave dries Germany's rivers, government ministers are at odds over what to do about it – re-engineer the waterways or restore them to their natural state.

As a heatwave dries Germany's rivers, government ministers are at odds over what to do about it - re-engineer the waterways or restore them to their natural state.

As a heatwave dries Germany's rivers, government ministers are at odds over what to do about it – re-engineer the waterways or restore them to their natural state.