Soil conservation projects involve the management of natural systems. To establish how the integration between technical frameworks and economic methods should take place, one has to define first the "focal point" of integration. Integration may be achieved at the level of an individual project effect. The work of the economist begins with the establishment of some notion of land/soil productivity based on yield projections which have been estimated by the agronomist. These estimated yields depend upon the volume and characteristics of existing soil. Soil conservation measures should however, decrease the frequency and severity of floods. The objective of the evaluation process is to assess flood damage costs "with" and "without" a given flood control project. The value of the financial investment will depend on which type of "design flood" is used. The estimation procedures of the hydrologist and the agronomist will determine the quantity of output foregone due to any given type of flood.