Similarly if the national taboos frowned on navigation and smiled on fertilizer, let us say, the cycle would be almost identical. Nor does it stop here. Large reservoirs demand the removal of many houses, which calls for an intelligent resettlement program. Large reservoirs demand an extensive replanning of railways, highways, schools, and recreation areas. The forest cover which is to check erosion calls for permanent management and many jobs for fire patrollers and forest workers.
Malaria is less lethal than yellow fever, but it is at least as hard to eradicate.
Water control ties in with fish and wild-life preservation, with purification of streams polluted by city sewers and industrial wastes. Such are nature's demands. There are other functions which are somewhat more indirect, such as land classification, including aerial mapping, a program for the use of marginal lands, and the development of domestic industries to supplement agriculture and provide employment. We start with navigation and end with a pretty comprehensive program of regional planning. We could start with flood control or with power and arrive at substantially the same program.