If we make the major rivers restored first, the floods from the tributaries are fundamentally prevented.
As Nation Rivers, the Four Rivers are of big scale and holding lots of inhabitants around them. In the undesirable case of flood, not a few calamitous damages are predicted, that is why we restore the major rivers. Of cause we are bearing the improvement works on the tributaries in mind. Notwithstanding, once the levels get lower from the main rivers, the safeties of tributaries are automatically secured by double effect.
