Dilapidation begets disrespect, and the abused and often repellent waters of the upper estuary are undoubtedly subjected to much additional miscellaneous pollution by people who believe perhaps that a little more cannot possibly matter. Again, Federal or Federally connected institutions have not been setting the best possible example, and there are many of them around the capital city. Unwarranted waste discharges of one kind or another have been traced to most of the military installations fronting the river, to military hospitals, to government heating plants, to the National Zoo, to National Parks, and to similar Federal sources including the marinas already mentioned. In most cases, measures are now being taken to eliminate these discharges, but it is a commentary on the complexity and difficulty of the whole task of dealing with pollution that at the level of government where real concern with the problem has been acute for a decade or more, and furthermore at and around the very seat of that government, such practices should have persisted this long. [Illustration] [Illustration] Junk and debris of all descriptions infest the metropolitan river, floating about, washing onto the shores, poking up stolidly here and there out of mudflats. Most items in a dreary inventory that might be compiled would turn out to be something that was discarded somewhere it didn't belong by someone who did not want to go to the trouble to put it where it did belong. Therefore, the main source is undoubtedly simple disregard for the sensibilities and rights of others, multiplied and complicated by the immense number of people in the metropolis and the wide territory they occupy. In our study of Rock Creek last year, some powerful subsidiary reasons for the prevalence of debris turned up also, ranging to streetcleaning methods and the inconvenient hours kept by some public dumps where citizens have to carry their larger trash. Metropolitan problems are seldom simple, and many of them in one way or another manage to inflict a part of their complexity on the river at the national capital, which is sad but possibly appropriate in a time like the present. The lower estuary Downriver from the main effects of the metropolitan complexities, the widening brackish and salt portions of the Potomac estuary form a generally healthy body of water, though changes loom as the metropolis moves inexorably outward from its center and as hitherto remote Tidewater areas are brought more and more under the influence of modern ways of being. Localized problems of pollution point to general dangers that will certainly materialize unless safeguards are set up in time, for estuaries are delicate, immensely productive, and still somewhat mysterious aquatic environments that have been and still are too much taken for granted. [Illustration] [Illustration]