Abstract
We analyse the cooperative aspects of two projects carried out by economists and engineers within an applied research institute. The first one involves both the research field and mathematical tools, the second one only the research field. In the case of water resource management, hydraulicians and economists are all concerned with the issue of time delay between the control variables and some of their effects on the state variables. One of the important current issues for the economists is to determine when the optimal exploitation of a renewable resource is sustainable, and in particular to work on the problem of the fall of the ground-water table in many of the most populated countries of the world. For hydraulicians time delay is a major concern when designing robust and stable control systems for irrigation canals. Both work for a better use of water resource in irrigation systems. The second research field consists of natural hazard management, a field for which economists still lack a comprehensive corpus of results. This make a pluridisciplinary approach more difficult to implement. The undoubted benefit that society as a whole would reap from a greater cooperation between engineers and economists, and its potential contribution to the improvement of economics and engineering, should encourage further pluridisciplinary projects.