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Show PART II NATURE, USE AND MANAGEMENT OF WATERSHED LAND lands are intermingled among other ownerships. This ownership pattern complicates watershed management since programs must be coordinated over large watershed areas to be effective. Within the national parks erosion, flood, sediment, and fire are ecological factors that contribute to the perpetuation of plants and animals native to a specific habitat. They are the natural forces that maintain the unique, scenic, and scientific values of the parks. The management objective is to preserve the environment in a natural condi- tion. Consequently, only minimal control measures have been made to stabilize problem areas originating from nonconforming uses such as grazing. The management of national monuments is similar to that for parks and control measures are limited to that needed for protection of primary values considered historically significant. Programs for the prevention and correction of erosion and soil or vegetation deterioration are permitted in national recreation areas. Trends and Progress to 1965 Federal land Early development of U. S. land law and policy stressed disposition of public domain lands as incentive to build the national economic estate. Concurrently with this development, intensifying uses of the unappropriated domain were experienced. This led to destructive overuse of the vegetal cover on both range and forest land. The advantage was sought by just about every user through whatever means he could command. Having natural wet and dry cycles with overgrazing by wild animals has also contributed to the problem. As depletion of the vegetal cover took place over the years through grazing, tree cutting, mining, fire, or other agents, the ecology which prevailed before the coming of white man was disrupted. The erosion rate was greatly accelerated and significant soil movement started on pre- viously stable areas. Concentrations of runoff gullied lowlands and caused sidecutting of streambanks and scouring of channel bottoms. Among the economic consequences were: 1. Greatly increased downstream sediment yields clogging channels and filling reservoirs. 2. Deterioration of productive valley floors through gully dissection and lowering of water tables. 3. Concentration of floodwaters in torrential flows which previously provided natural irrigation of bottomlands. 4. Deterioration of water quality in streams by increased sediment load, salt concentration, and temperature. 14 |