extensive, it should be suitably paragraphed for convenient reference. Paragraphs will be numbered consecutively without reference to headings.

281.1. Authority.-Cite the authorization for the examination and quote verbatim the item of law or the Committee resolution covering the report being made. Subject to prior approval by the Chief of Engineers, reports may be made to cover more than one authorization. In such cases, specific reference will be made to such approval and to each item of authorization.

281.2. Prior reports.-Describe prior flood-control reports on the stream, or streams, naming the improvement then desired, giving the document numbers and recommendations of the Chief of Engineers. If many prior reports have been made, they may be listed in tabular form.

281.3. Description.-If the authorization is limited to a definite area such as a reservoir, city or improvement district, briefly describe the area, including its relative location on the stream and waterway. If the scope of the authorization is broad and general, as for an entire watershed, the order of presentation will be: geographical description of watershed, stream, valley, and tributaries; topography; general geology; stream slopes; cross-sectional dimensions; channel flow capacities; climate; and other data that may be pertinent to a full and clear description. Give reference to published charts or maps of the area or watershed and to the general map or maps accompanying the report.

281.4. Economic development.-Describe the population, population distribution, occupation and industries, land use and development, agriculture, resources, and transportation facilities including navigation improvements.

281.5. Precipitation.-State number, length of record and location of rainfall stations, with yearly average and other essential data, including data pertaining to notable storms in or adjacent to the area under investigation. Likewise where applicable, data pertaining to snowfall should be included. An intensive study of precipitation within the watershed is the indispensable foundation of a sound flood control plan.

281.6. Run-off.-List river stage and stream gaging stations with their location, drainage area and period of record, giving the essential stage and discharge records of high and low waters, including total flood volume, using hydrographs where available. If the authorization includes use of water for navigation, irrigation, or power, or other purpose, give a clear idea of the adequacy of the stream flow for such purposes. U. S. Weather Bureau and all other records of storms which have caused floods must be studied with the corresponding run-off records. Only by such study and detailed analysis can the relation between intensity and duration of rainfall infiltration index of the drainage basin and run-off be determined. All previous flood heights may be exceeded in the immediate future. No report is complete which does not include a determination of the flood heights that would result from the worst meteorological and ground conditions which the U. S. Weather Bureau considers a possibility from a single storm or a succession of storms combined with the most unfavorable run-off conditions.

281.7. Floods.-A full description will be given of the height, maximum discharge, duration, volume (expressed in run-off in inches over the drainage area) and dates of occurrence of floods of record. The probable frequency of floods should also be fully discussed. Special effort should be made to list flood occurrences antedating the periods covered by continuous stage and discharge records, to the end that all floods of historic importance will be taken into account. All high water marks placed by inhabitants, municipal waterworks, railway, county and State bridge departments as well as high water marks in the form of driftwood and sediment deposited in crevices should be searched for. Where historic

floods exceed in height those for which discharge measurements and gage heights are of record, their discharges should be computed. References to floods as "a 100-year flood,” “a 500-year flood,” “a 1000-year flood” will not be made. An assumption as to probable future frequencies of uncontrolled floods is necessary only for the purpose of estimating the economic value of a project for flood control. 281.8. Extent and character of flooded area. Give an estimate of areas in the flood plain; type and extent of improvements; value and productivity of areas under present conditions; physical damage and danger to life resulting from floods; and appropriate data on centers of population, highways, railroads, bridges, and other structures affected, including estimated annual damages caused both directly by floods and consequentially or indirectly by floods and flooding, and effect on property values.

281.9. Existing flood-control projects.-Give an exact statement of the existing War Department flood control project and a clear statement of the status of completion thereof. Give the total cost for new work and for maintenance, and the present approved annual maintenance cost. This information should conform to that contained in the last printed Annual Report of the Chief of Engineers. If the existing project consists of several separate units, part or all of the information called for may be given in tabular form. Where affected by the proposed improvement, give a similar statement for the stream into which the one under discussion empties. Describe any changes in the existing project that have been recommended to Congress by the Chief of Engineers, but not authorized, citing the report or document. This should conform to a similar paragraph in the Annual Report of the Chief of Engineers, unless such changes were recommended subsequent to the last Annual Report of the Chief of Engineers.

281.10. Improvements by other Federal and non-federal agencies.— (a) Give nature, extent, and total cost of flood control works, and works for the beneficial use of water, constructed by other Federal agencies; also the extent to which local interests cooperated in these improvements and the extent to which such works have been coordinated with the authorized War Department project, as well as a brief statement as to the adequacy of these works.

(b) Give the nature, extent, and total cost of flood control works, and other works for the beneficial use of water, constructed by states, political subdivisions thereof and other local interests; also the extent to which these works have been coordinated with Federal works and particularly with those constructed in the primary interests of flood control and navigation, including a statement as to the present adequacy of the works.

281.11. Improvement desired.-State the improvements desired by local interests and by whom proposed. Give place and date of public hearing, by whom held, and character of attendance. Give reasons advanced in justification for improvement desired. Where improvements are urged by responsible interests, other proposals made by uninformed parties and clearly not justified may be disregarded or briefly touched upon. State what cooperation if any, has been offered by local interests, describing their willingness and ability to fulfill conditions of cooperation prescribed by law in Flood Control Acts.

281.12. Discussion.-Under this heading discuss the arguments and data presented by local interests or secured as a result of the examination in such manner as to reach a logical conclusion. Analyze carefully and conservatively the benefits from the proposed improvement. Statements and estimates presented by local interests must not be accepted blindly at their face value but must be reduced to realities, stating in general terms whether their estimates or opinions are reasonable or believed conservative or liberal. Discuss all possible methods of flood relief, such as impounding or regulating reservoirs,

In

levees, channel rectification and enlargement and diversion of flood waters. connection with the study of control by reservoirs the possibility of economical development of storage capacity for beneficial use of water such as navigation, hydroelectric power development, irrigation, domestic and industrial water supply, and abatement of stream pollution should be given consideration, regardless of whether local interests have expressed any desire therefor. Discuss, generally, the beneficial or adverse effect on existing works on this or other streams lower down, and upon areas subject to flooding under conditions likely to result from the adoption of flood control improvements discussed herein. In a broad manner show whether, with due consideration of all direct benefits and those not susceptible of evaluation (which should be enumerated), further investigation of the subject appears to be warranted at this time. The viewpoint should be eminently fair and reasonable. Subjects allied to flood control, such as navigation, irrigation, water power, municipal and industrial water supply, abatement of stream pollution, shore line changes, caving banks, and the maintenance of permanent pools in reservoirs for recreation and wild life, if not of sufficient importance to warrant separate paragraphs with suitable headings, should be included under "Discussion." In appropriate cases statement should be made as to whether further investigations are desirable in connection with these special subjects, and the extent and character of the desired investigations. A further statement should also be included as to the general nature and extent of changes in utility facilities that would probably be involved in the proposed flood control improvements such as pipe lines, communication and power lines, railroads, highways, and bridges.

281.13. Conclusions.-State in a general way the methods considered most suitable for flood control and the views of the reporting officers as to the probabilities of developing a satisfactory and economically justified plan of improvement.

281.14. Recommendation.-The report will conclude with a recommendation that a survey and estimate of cost should be made, stating clearly the scope and character, or with a statement that further investigation and report on the locality is not warranted by the United States at this time and that no survey is recommended.

281.15. Report of the Division Engineer.-The report of the Division Engineer will be in the form of an indorsement with only such presentation of detail as may be essential for explanation of views and recommendations divergent from those of the District Engineer. Where the Division Engineer concurs with the District Engineer a statement to this effect will be sufficient.

SURVEYS, NAVIGATION

282. Survey reports.—Survey reports for navigation will be complete in themselves, without requiring reference to reports on preliminary examination. They will include the data contained in the reports on preliminary examination amplified and modified as may be necessary to conform to the latest available information.

282.1. Shore Protection Board. When a survey, or a review thereof, of an improvement at the mouth of a river or inlet which might affect the adjacent shore line is assigned to a Division Engineer, he will arrange direct with the senior member of the Shore Protection Board for the cooperation of the Board in the necessary investigation and studies. Copies of the report of the Shore Protection Board will be sent direct to the Division Engineer for transmission with report on the survey.

282.2. Recreational boating and fishing boats.-(a) Congress in Act approved February 10, 1932, (47 Stat. 42, 33 U. S. C. 541), defined and supplemented the term "commerce" as applied to waterways to include the use of waterways by seasonal passenger craft, yachts, house boats, fishing boats, motor boats, and other similar water craft, whether or not operated for hire. Reports on projects intended primarily to serve the type of commerce defined above should in general conform with other survey reports for navigation, with such modifications as may be necessary to assure consideration of the special requirements of the

commerce.

(b) In general, a small boat harbor should have the following facilities: (1) A safe entrance.

(2) A protected anchorage, mooring area or bulkhead for tieing up, adequate for the accommodation of transient boats.

(3) An adequate frontage with stalls or slips for local boats.

(4) A channel along the frontage reserved for local boats of sufficient width for maneuvering in and out of stalls or slips.

(5) A public landing with provisions for the sale of motor fuel, lubricants and potable water to all on equal terms.

(6) Stalls or slips for transient boats, dockage and repair facilities, telephone service and police and fire protection.

(c) Items (1), (2), and (4) are required for the reasonable accommodation of general navigation and should be provided by the United States. Items (3), (5), and (6) are of such nature that they should be provided and maintained by local interests. Only such part of the cost of facilities provided by local interests as is not self-liquidating through rental or similar charges should be considered as a contribution to the cost of the project.

(d) Improvement by the United States should, in general, be undertaken only in cooperation with a properly constituted public body having authority to cooperate financially and to operate essential facilities. The sponsoring body should operate without profit and any rental charges should be reasonable and subject to the approval of the Secretary of War.

(e) Benefits that will accrue from the provisions of facilities for small boats are difficult to evaluate and largely indeterminate, particularly in the case of recreational craft. One method of evaluation is to estimate the number of boats that will use the facility and the aggregate amount of the annual cost to which the boat owners are now put for their enjoyment of this form of recreation; then to apply to this aggregate a suitable factor to estimate the benefit that may be expected to result from the proposed improvement. Any factor adopted should be selected only after a full investigation of annual charges for representative types of recreational craft and a study of such information as is available on the cost of providing small boat harbors.

(f) The determination of the extent of local contribution to be required will take into account the relative importance of the improvement to local small boat owners and to general small boat navigation and the probable ability of local interests to make financial contributions. The individual judgment of reporting officers must be relied upon in the determination of the amount of such contribution, but full information to permit reviewing authorities to pass upon this matter should be contained in the report, or, in appropriate cases, in a separate letter accompanying the report.

282.3. Form and order of report. The survey report, whether prepared by the District Engineer, Division Engineer, or a board of officers, will in subject matter, arrangement, and context follow in general that prescribed for the preliminary examination report, with the modifications and additions discussed under certain

headings of the following outline. It is desirable that the general arrangement be closely followed in order to facilitate study by reviewing authorities. The main report will not be filled with statistics, descriptions of methods and procedures followed in making studies, or material not essential to a full understanding of the problems involved. Such material should be contained in appropriate appendices. Plates and exhibits will not be bound in the text of the main report, but may be appended at the end of the text.

282.4. Authority.-Cite the authorization for the survey and quote verbatim the item of law designating the particular locality. If the report covers more than one authorization, make specific reference to each. If a preliminary examination report has been submitted, include a statement to show that the report has been reviewed by the Board of Engineers for Rivers and Harbors. State the scope authorized for the survey.

282.5. Bridges.-Every report should contain full information concerning all existing bridges that will be affected by the project covered by the report. In case the alteration of any railroad or highway bridge will be required to prevent interference with the execution of the project, or with the free navigation of the improved waterway, the report should include an estimate of the cost of making the necessary alteration and an expression as to whether the circumstances justify the assumption by the United States of the whole or any part of the cost. 282.6. Improvement desired.—Add any modification of the desires of local interests that may have been presented subsequent to the submission of the report on preliminary examination.

282.7. Commerce.—A detailed and accurate estimate of the prospective commerce will be given. When modification of an existing project is under consideration, the report will contain statistics of the waterborne commerce and traffic for as long a period as is pertinent, and the origin and destination of the principal movements will be described. When the establishment of a new inland waterway, port, or similar facility is under consideration or when enlargement or extension of an existing project is proposed, a survey of the commerce of the tributary area will be made to secure data on origin, destination and cost of movement, and an analysis of this commerce will be made to determine the portion which would use the waterway and the saving that would result from waterway movements. Additional instructions are contained in paragraph 282.11—(i) and 282.11-(j).

282.8. Survey.-State the character and extent of the surveys made without going into details regarding the methods followed. In cases of special interest, these should be described in an appendix. List the maps and drawings submitted; or if numerous refer to lists in an appendix.

282.9. Plan of improvement.-State the plan or alternate plans of improvement considered with estimates of construction cost in sufficient detail to permit of a full understanding of each class of construction work. The District Engineer will personally scrutinize these estimates to make sure that they are adequate but not excessive. Proper consideration should be given to the character and extent of the various items of work; to the cost of doing the work by Government plant with hired labor, and by contract; to the level of unit costs in the area, and the probable effect of changes in the cost of labor and materials before the work is completed. It is preferable to make an over allowance for adverse conditions and obtain an estimate of cost which may ultimately exceed the actual construction cost, rather than to make an estimate which will fall short of the actual construction cost if there is an abnormal increase in the cost of labor and materials. In the preparation of projects, unless otherwise expressed, the channel depths referred to will be understood to signify the depth at mean low water in