Landscapes of calculation: the design agency of methods of assessment at the Ayalon project

Assessment techniques such as cost-benefit analysis are used to evaluate and approve public sector projects and decide among different design alternatives. Therefore, they have a considerable influence on the materiality, performance and reception of infrastructural landscapes. This paper analyses the dynamic interaction of assessment techniques with other forces and modes of knowledge that produce the built environment using the historic case study of the Ayalon Project in Israel. The project transformed a seasonal river into a depressed urban expressway, railroad, and flood control facility. The research opens the ‘black box’ of cost-benefit, multiple-criteria and risk analysis to reconstruct the complex chain of decisions that shaped the regulation canal, whose periodic flooding is regarded as a national scandal. Its main conclusion is that the recursive activation of these portable techniques contributed to the Ayalon’s unstable performance and landscape singularity.