In the last decade, optical core network planning has stirred a new trend in research and development by taking into account the impact of transmission impairments on the optical reach. Many investigations, carried out in this area, have shown that translucent networks represent a cost-effective solution to cope with physical layer impairments in large-scale optical networks. In previous work, we have formulated the translucent network design problem as an integer linear program (ILP). Our concern is to minimize the number of regenerators while satisfying all the requests. An optimized network design is obtained for a given set of traffic requests. Nevertheless, such a network design strongly depends on the traffic requests. In this paper, we are concerned with translucent network design and a tradeoff between optimized network costs on one hand, and flexibility against future traffic uncertainty on the other hand. To this end, we extend our ILP formulation to multiple traffic forecasts. Our aim is to judiciously deploy regenerators so that network design remains optimized under different traffic forecasts.