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Show sedimentation, and stream aggradation and degradation. Detailed surveys of representative reservoirs should be completed. Detailed erosion surveys should be made to delineate the source areas of sediments and their relative importance to the sediment problem. Topography.-Larger scale maps are required in this phase in addition to those described under general cover- age. Map scales should be adequate to show details re- quired for plans, drawings, and specifications of construc- tion projects. Map scales usually vary from 1:24,000 to 1:12,000. Mapping required at the smaller scale is gen- erally performed by the basic data agency. Larger scale mapping is done or contracted for by the development agency. Geology.-Geologic examinations in detail are required at all proposed construction sites during this phase. Geologic factors affecting the preparation of engineering plans and specifications should be evaluated and presented in understandable form. Detailed site investigations are usually performed by the geologic staff of the construc- tion agency. General coverage geologic maps greatly aid detailed site investigations in this phase. More de- tailed study of individual mineral deposits and ground water reservoirs may carry over from the preceding phase. Geologic maps for this phase vary in scale depending upon the scope of the project and the nature of geologic forma- tions. Soils.-This phase may require more complete and comprehensive data on soils for land treatments and man- agement; they include descriptions and analyses of in- herent characteristics of soil profiles, and external features such as degree of erosion and stoniness. Such facts pro- vide a framework for organization, evaluation, and exten- sion of information on use and management of soils within fields, in pastures, and in forests to areas of like soils and land features. Soils data collected in this phase should be sufficient for classification of land in terms of safe use and management, for recommending and applying meas- ures on site for control of runoff and erosion, for guidance in use and management of specific tracts of land, and as general aids in estimating storm runoff, erosion, and sedi- ment production as they may affect water resource develop- ments. Fish and wildlife.-Information regarding vegetation and land-use practices; fish (including shellfish and crustaceans); ¦wildlife habitats; populations and harvests; fishing and hunting; hatchery opportunities; relation of fish to stream obstructions; and local and national im- portance of trie affected fish and wildlife, is collected from all available sources and censuses and surveys are conducted when needed to overcome deficiencies in data. All aspects of the proposed project are studied in detail and estimates of future effects on the life cycles of fish and wildlife are made. Plans and Specifications and Intensive Coverage The title of this stage in project development is self- explanatory. It is the prelude to and a necessary basis for actual construction. For this stage in project development it may be nec- essary to undertake some still more detailed investigations, a phase in resource surveying which is called intensive coverage. These, in respect to each of the principal re- source categories involved, are discussed as follows: Hydrology.-The intensive coverage phase of data col- lection for the variable hydrologic factors consists pri- marily of collecting data for detailed project design. It is often desirable or necessary to continue collection of certain items of these data after the information has sup- plied the immediate need in order to serve as useful units of general coverage relating to the national network of data or for project operations. Sedimentation.-In this phase periodic resurveys of ranges in, above, and below proposed reservoir areas to measure long-term rates of sedimentation are made to determine possible disposition of sediment within pro- posed reservoirs, and aggradation and degradation ten- dencies in the channels above and below such reservoirs. Detailed surveys of small reservoirs and sub-watershed erosion above proposed reservoirs are undertaken for the purpose of analysis and determination of rates of sedi- mentation. It would be desirable to establish new sedi- ment measuring stations above and below reservoirs to determine trap efficiencies and to continue in operation certain of the sediment-sampling stations in order to ob- tain long-term records and to determine changes in vol- ume and character of sediments as a result of watershed and sub-watershed treatment. Size analysis of sediment in channels and reservoirs, density determinations of sedi- ment in reservoirs, and similar studies related to construc- tion and operation should also be made in this phase. Topography.-Intensive coverage maps cover a broad field of requirements ranging from a detailed investiga- tion of a limited area to large-scale plans for a construc- tion project. These are usually prepared by the con- struction agencies at scales of 1:12,000 or larger. Geology.-Geologic data are collected in this phase in much more detail than in the preceding phase. As de- tailed plans are developed, need frequently occurs for in- tensive study of particular aspects of geologic formations by the construction agency. Soils.-For intensive coverage in locating and in plan- ning drainage and irrigation projects, information must be more complete as to soil characteristics and its beha- vior under irrigation or other treatment, and must show locations and limits of different kinds of soil more exactly to furnish the basis for intensive classification and subse- quent land preparation. Fish and wildlife.-In this phase an intensive investi- gation of the area is made, in cooperation with the State, to select appropriate sites for development, and deter- mine plantings, fencing, or other developments required, and management needed. The proposed development is evaluated on the basis of the wildlife populations and har- vests expected to occur, after a complete biological study. Similarly, plans for fish ladders, fish screens, and other fish-protective devices may also be prepared. Socio-Economic Data.-Basic socio-economic data are needed in this phase of data collection to confirm justifi- cation of the project after possible changes in price levels immediately prior to construction. See table I. Construction Stage and Phase The title of this step in project development is self- explanatory. 334 |
