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Consideration of acres in which only practical measure of flood control is improvement and enlargement of existing outlets; design of drainage in these areas; removal of excess flood waters at minimum cost; paper based on experiences in design of Hillsboro Canal, Florida.

Synopsis. The first part of the Paper describes the major rivers of Khuzistan, the ancient irrigation systems, and the possibilities of reviving irrigation on a large scale in the province without deteriment to navigation on the Karun. Used in conjunction with the Ab-i-Diz, a tributary of the Karun, and the River Karkeh, the potentialities of a suggested impounding reservoir on the Upper Karun for irrigation, and for hydro-electricity and flood control in the province are described in general terms. The silt problem is also discussed. The second part of the Paper describes certain deductions made on the regime of the Shatt el Arab. The rise and fall of the water-level in the inland delta of South Iraq is influenced by the obstruction to the flow of the Shatt el Arab caused by the discharge of the Karun, and the suggested impounding reservoir on the Upper Karun offers possibilities for flood control and land reclamation in South Iraq.

The writer conducted an investigation of the relationship between the rainfall accompanying the Kanogawa typhoon and its resultant landslides, including landslides and the transportation of materials produced by landslides, and the scouring and deposition produced by the flood of Sept. 26, 1958 in the upper drainage basin of the Kano River (Fig. 1). Many investigations have been made of the various forms of damage caused by heavy rainfall, such as landslides, scouring, transportation and deposition produced by flood water, but little work has been done on the relationships between these phenomona from the upper to the lower course in a drainage basin. The main purpose of this paper, therefore, is to make clear these relationships. The conclusions of this paper are summarized as follows: 1) In the upper drainage basin of the Kano, many landslides have occurred as a result of heavy rainfall accompanying typhoon No. 5822. The severity of these landslides is especially high in an area from the southwestern to the northeastern part of the town of Yugashima (Fig. 2). These landslides have also coincided strongly with the area of heaviest rainfall even occurring in the area of the same rock type. From these observations, it might be said that there is little relationship between the distri-bution of landslides and of rock types, but that there is positive relationship between the distribution of landslides and of rainfall amount. The area where landslides are most frequent coincides with that the amout of rainfall is from 550 to 700mm. during this period of the typhoon (Fig. 2, Kawamura's Figs. 3 and 4). 2) Many boulder-size terrace gravels were also removed from riversides to stream beds by the scouring of flood water in the upper course from Yokose which is a town of Shuzenji (Fig. 1). Materials produced by landslides are mostly deposited on the mountain-sides and in small mountain stream beds except for landslides extending to the river beds. 3) It has been found by many researchers that the materials produced by landslides were transported only a very short distance, while the writer found that the bulk of the materials—derived from the great landslide in Ikadaba which is situated in the upper reach of the Omi River (Fig. 4, Tab. 3 and Photo 1) and composed of pumiceous sand and gravel was transported very long distance by the water of only one flood. 4) The locality of scouring and deposition by flood water could be determined by geomorphological characteristics such as the relationship between the ratio of river-width to valley-width and the stream gradient (Fig. 6, abscisa: the ratio of river-width to valley-width, ordinate: stream gradient). Geomor-phological factors determining the locality of scouring and deposition by flood water seem to be very important for flood control.

This paper deals with floodplain land use management approaches for urban flood damage control. These alternatives are important because traditional flood control projects, such as levees, channel improvements, and reservoirs, are not always capable of correcting the physical and economic conditions that give rise to flood damage. It is expected that land use management will complement engineering works and lead to more effective use and development of floodplain lands. The paper presents a computational technique for evaluating alternative land use assignments based upon the economic value a community gains from its land. A linear programing model is developed that identifies economically efficient combinations of (1) spatial and temporal planning of urban land use, (2) site elevation through landfill, and (3) flood proofing of buildings.

The writer's remarks will be confined to a discussion of the paper by FRED PAGET on ‘The use of snow-surveys as an aid in flood-control operation of reservoirs”, presented at Corvallis, Oregon, on June 16, 1943, and published in the Transactions of 1943 of the American Geophysical Union. In that paper it was shown how the information revealed by snow-surveys may be applied to the problem of operation of reservoirs for the control of snow-melt floods and yet allow maximum conservation of water for purposes of irrigation and power. As stated by Mr. Paget, two possible extreme variations in the manner of the occurrence of runoff must be considered—early snow-melt and late snow-melt. One of these conditions makes flood-control the most difficult and the other makes the filling of the reservoir at the end of the season the most difficult. Flood-control requires that reservoir-space be provided to take care of runoff from early melting, while water-conservation requires that the reservoir be not kept so low that runoff from late melting would fail to fill it.

Service has relied on upland farming to supplement waterfowl food on some of its southeastern refuges for more than a decade. This is particularly important on multiple-purpose, power and flood control reservoirs, where extreme fluctuation prevents natural food production. Farming is the basic management tool used on public shooting areas managed by several of the southeastern states, and on a number of private or clubowned hunting preserves. Background material for this paper has been gathered from various southeastern refuges managed by the U. S. Fish and Wildlife Service, notably from the Wheeler Refuge in Alabama, the Tennessee and Reelfoot Refuges in Tennessee, the Santee Refuge in South Carolina, and the Kentucky Woodlands Refuge in Kentucky. Some material has come from state-managed public-shooting grounds located in the Tennessee River valley. Shore-line plantings of upland crops and farming in dewatered areas are management tools in local use in the southeast, but are not considered within the scope of this paper. The success that has attended upland farming as a management tool has been spectacular in many cases. Through this means, large concentrations of geese have been brought into areas where they were once rare or absent. Duck u age, limited by natural food shortage, has increased as much as several hun

The paper presents a method for deciding how best to operate a multipurpose reservoir which is subject to conflicting demands. The method is based on decision theory. It can be used to derive reservoir rule curves when flow forecasts are not available or to provide guidance in real time on what is best to do when forecast information is available. Because of the complexity of reservoir operation, decision theory could not be applied directly. A special bridge between theory and practice had to be devised. The procedure is illustrated by application to Okanagan Lake in British Columbia, a lake which is operated as a reservoir for both flood control and storage of water for irrigation purposes.

A technique of analysis is presented by which the dynamic operation policies for planning complex reservoir systems producing hydroelectric power and providing water can be optimized for the maximum return from firm water, firm power, dump water, and dump power. The technique provides for complex constraints, such as mandatory flood control reservations variable in time, fish, wildlife, and recreational releases, navigation minimum flows, etc., as well as evaporation losses and inter-basin diversions. The paper presents in detail the operational analysis of a component reservoir-river system and the procedure to be used to combine optimally a number of such subsytems into a coordinated, mutually reinforcing, multiple-river system.

The Congress has directed that water resource development plans and projects be comprehensive in that adequate consideration be given to all uses that are of value to the public. Besides power, flood control, navigation, and irrigation, statutory support is specifically mentioned for recreation, fish and wildlife, water supply, and water quality control. The general principle applied is that each use should be developed so the difference between benefits and cost is maximized, although in applying this principle it is recognized that latitude must be exercised to allow for benefits or effects of public concern that cannot be appraised in monetary terms and for choice between conflicting uses. A major feature of the paper concerns the concepts involved in hydro power project formulation. To determine whether power facilities should be included in a water resource project, tests are applied to ascertain economic and financial feasibility. The application of these concepts or corresponding ones used earlier has resulted in the authorization of power facilities in the southeast the capacity of which totals 1,647,000 kw with an average annual output of 3,875,000,000.

Paper covers effect of storms and floods on hydrologic criteria used by Corps of Engineers in design of flood control structures.

Governmental agencies have been instrumental in the construction of numerous dams and other control structures in the small watersheds of the State of Mississippi. Although some of the consequences are predictable, there are some effects which are not yet well defined. This paper concerns the physical effects of such works on a particular stream and its channel. As was anticipated, peak discharges appear to have been somewhat reduced. Changes in channel cross-section depend, to some extent, upon location along the stream. However, there appears to have been a narrowing of the channel in that portion of the stream for which cross-sections were available.

T HE title of this paper suggests the question: what, if any, characteristics of the humid regions have a unique impact on sharing costs of flood control investments? Would these characteristics impose any restrictions on or require extensions of conventional economic criteria for cost sharing? Certainly the contrast of the physical environment of the East with that of the arid West requires different techniques of water management. With a larger, more concentrated population, older and more extensively developed private investments, and the complex institutional commitments that have evolved with them, the means for achieving efficiency and equity in cost sharing also may not be the same as those that would apply in the arid West. In the East, the closer and more in-plains, storage areas, and water use demand that investments in stream management be scheduled and integrated with scrupulous observation of their impact both in the present and over time if acceptable levels of efficiency and standards of equity are to guide flood control investments.

The River Watarase flows out from the western part of the Nikko Volcanoes, and runs southward through Ashio mountainland and empties into the River Tone in Kwanto Plain. Recently this river flooded frequently and the river floor of its lower course has been elevated. by deposits. The writers studied on the transporting materials of this river, specifically referenced to the upper course in Ashio mountainland from the geomorphological and potamological point, of view as a fundamental survey for civil engineering. In this paper, the transporting materials of Watarase River are stated briefly. 1. Suspended materials are supplied in large quantities from the settlingponds of Ashio Cupper Mine and its Refinery situated on the upper stream of this river. These materials are transported and deposited in the lower course and in the flood control lake, Akamanuma. 2. Solution is leached out in a great deal from Akagi volcano region because this volcano erupted in quaternary and its rocks are fish. Consequently the amount of solution of the tributaries from this region is far more than that of the tributaries from palaeozoic slate and granite regions in this mountainland. In Akagi region, as the volcanic ash and detritus are less cohesive and many landslips happen, so the.boulders and gravels of andesite are heaped on this river bed near Omama Town at the entrance to this mountainland. Therefore the fluvial gravel deposits of quartz porphyry and liparite from the headwater of the River Watarase are less than those of the anndesite. The elevation of river floor is mainly due to the detritus from Akagi Volcano. 3. The palaeozoic slate is apt to become small gavels, but granite is apt to become large boulders and not to become gravels. Granite. boulders are disintegrated abruptly into small pieces when they are transported in the river. 4. About 10meters gravel bed in thickness is seemed to be deposited in the flood plain without any depression in the river which has the same physiographical features as the River Watarase. On such thickness of river gravel bed, we consider it to be renewed by several floods, and accordingly the river terraces which have such gravel beds are not to be called alluvial terraces in such rivers. 5. The bed loads of this river are on the increase lately and about 500, 000 q. m. of sands and gravels are transported during a year.

This paper discusses and compares the economic effects of alternative programs for coping with flood losses. Special emphasis is placed on the use of flood insurance. Also, the measurement of land-enhancement benefits is discussed in some detail. (Key words: Economics; flood control; insurance)

The Shellmouth Dam on the Assiniboine River is a flood control project now being built by the federal and Manitoba governments. The upper 50 ft. of foundation at the dam site is a medium to highly plastic alluvial clay deposit containing sand layers and lenses. This is underlain by up to 100 ft. of sands and gravels to shale bedrock.This paper describes the design, construction, and instrumentation of a test fill built at the site of the proposed dam, and includes summaries of pore pressure and movement observations, settlement studies, and stability analyses.

This Progress Report by the Task Force on Effect of Urban Development on Flood Discharges. Committee on Flood Control, Hydraulics Division, ASCE attempts to provide, as a guide for engineers, planners, governmental officials, and all others interested in the problems of urban runoff, an annotated up-to-date bibliography of reports, papers, and other material pertaining to the effect of urban development on flood discharges. The report includes a brief discussion of the impact on flood runoff which can be expected by urban development and the factors directly affecting the runoff regimen of a drainage area, as suburbs and cities replace the rural landscape. Included is a listing of pertinent research projects which are underway with identification of areas where, in the opinion of the Task Force, additional research is required.

By approximating a natural flood hydrograph to a single mathematical curve, the routing procedure has been reduced to a dimensionless differential equation. The computer solution, in the form of a pair of tabulated functions enables the length of spillway necessary to produce any desired reduction in the peak flood or any desired limiting head on the spillway to be obtained in a single calculation. The paper shows that only a very slight modification of the procedure is necessary to deal with a spillway having a variable coefficient, or with a reservoir or storage pound having a variable surface area.