AuthorClark, Robin B.
KeywordsHydrology -- Arizona.
Water resources development -- Arizona.
Hydrology -- Southwestern states.
Water resources development -- Southwestern states.
Flood plain zoning
Maximum probable flood
Cochise County (Ariz)
Earth resource technology satellite (ERTS-1)
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RightsCopyright ©, where appropriate, is held by the author.
Collection InformationThis article is part of the Hydrology and Water Resources in Arizona and the Southwest collections. Digital access to this material is made possible by the Arizona-Nevada Academy of Science and the University of Arizona Libraries. For more information about items in this collection, contact email@example.com.
PublisherArizona-Nevada Academy of Science
AbstractPopulation pressures on the land resources of Arizona have led to the sale and development of areas subject to flooding and because of the inadequacy of land use controls, the area is open to various land speculation schemes and unplanned subdivision growth. A floodplain delineation project was conducted for the planning department of Cochise County, Arizona, in which imagery acquired by earth resources technology satellite (ERT-1) and by high-altitude aircraft was employed. Parameters of the analysis included soils and geomorphology, vegetation, hydrologic calculations, and historical data. Floodplain soils lack developed b horizons, as compared to older, more mature soils not subject to flooding. General soil maps can only be used as guidelines, but a detailed soil survey can add significantly to the accuracy of image interpretations. Erosion-affected soil tones in areas adjacent to active channels proved beneficial in that the heightened contrast served to enhance resolution of vegetation-type boundaries. Hydrologic calculations were done based on valley cross-sections surveyed at two-to-three mile intervals. The historic data input into the system of floodplain delineation is dependent on the location of high-water marks and on obtaining a record of the amount of rainfall which resulted in the high-water mark.
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Simulation of Summer Rainfall Occurrence in Arizona and New MexicoYakowitz, Sidney; Southwest Watershed Research Center, Agricultural Research Service, Tucson, Arizona; Department of Hydrology and Water Resources, University of Arizona, Tucson, Arizona (Arizona-Nevada Academy of Science, 1977-04-16)Thunderstorms produce most of the annual rainfall and almost all runoff from arid and semiarid rangelands in the southwest U.S. A model was developed to be used for predicting runoff in river basins, flood plane zonings, estimating flood damage, erosion, and sediment transport, and estimating precipitation available for forage growth. This rainfall occurrence model has three parameters: elevation, latitude and longitude, and takes into account rainfall occurrence in 22 stations located in Arizona and New Mexico. From these variables, mathematical equations were developed in an effort to predict point rainfall occurrence. Estimates of the number of seasonal occurrences were used as a check of the equations within the model.
Feasibility of early flood warning in eastern Pima CountyChudnoff, Dan Avram.; Davis, Donald R.; Bradley, Michael D.; Ince, Simon (The University of Arizona., 1982)Interrelated physical, economic and social factors determine the viability of early flood warning systems to reduce damages and the loss of life due to flooding. A framework is developed to evaluate criteria for determining the feasibility of a warning system under flash flood conditions. A benefit-to-cost ratio for the early flood warning system is determined by quantifying both the reduction in property damages and loss of life due to a flood warning. The economic potential of a flood warning system is limited by both physical watershed constraints, such as length of warning time, and by a less than optimal response by floodplain users. It is shown that under flash flood conditions, the benefits of an early flood warning system are primarily derived from the saving of lives, and not property.
Some geomorphic models of flood hazards on distributary flow areas in southern ArizonaKemna, Stephen Paul,1963- (The University of Arizona., 1990)The Federal Emergency Management Agency (FEMA) uses a method for evaluating flood hazards on alluvial fans that assumes an equal chance of flooding along a radial arc across the fan surface. In southern Arizona there are distributary flow areas (alluvial fans) that do not conform with FEMA's assumption. Thirty-nine sample sites were chosen from the Basin and Range physiographic province in southern Arizona. These sites were classified into five categories of flood hazard; A, B, C, D, and E. The classification scheme is based on the potential randomness of flooding across each site. A method is proposed for locating the primary diffluence (apex) of a distributary flow area. Texture curve analysis is used to locate distributary flow areas on the piedmont plain. Two alternative methods, topologic analysis and a multiple regression model, are presented for evaluating flood hazards on distributary flow areas in southern Arizona. Only eight of the sample sites studied strictly conformed with FEMA's assumption of an equal probability of flooding along a radial arc across the fan surface. The topologic analysis may be used to determine if the FEMA method is appropriate for a given site. A multiple regression model provides rough predictions of the degree of flood hazard based on morphometric and hydrologic variables.