Abstract
Recently, the northern border regions of Mexico have experienced a rapid increase in population and urban growth. The most important factor for this development is the proximity to the Southwest region of the United States, and the locational predominance of the border regions stimulates development of agriculture, manufacturing and mining, and commerce and services. Consequently, these regions have higher income levels and higher rates of employment than the interiors of the country. But, the northern border regions have extremely low levels of income and higher unemployment rate than the adjacent southwestern regions of the United States. These differentials raise some serious international problems. Some of these are crime, illegal entry, public health, sewerage, water allocation from rivers, and air pollution. There are many twin cities along the international boundary, and yet there are conspicuous contrasts of income level and standard of social capital accumulation between the two groups of twin cities. The water apportionment and management to cope with the increasing demand of use of water and the sanitation problems are unsolved between the United States on the upper basin and Mexico on the lower basin. Accompanied by the development of manufacturing and urban growth, damages from air pollution are becoming severe. The differences in the legal, technical and economic characteristics between the two countries have hindered joint surveys and measures for air pollution control. Accordingly, the international boundary acts as an artificial barrier. The problems such as water supply and sewerage are eminently regional in their nature, and the solution of these problems should not be affected by the man-made boundary. Also, the problem of air pollution is similar and measures should be taken on the consideration of an environmental system which is integrated as a geographic region. The obstacles of the international boundary should be surmounted and the solutions to these problems should be based on the new concept of a regional system.
