Comprehensive Flood Plain Studies Using Spatial Data Management Techniques

"The Corps of Engineers Hydrologic Engineering Center has developed techniques that perform the spatial data analysis approach and individual structure approach and work is near completion on an integrated analysis package. The capability therefore exists to perform damage appraisals in a manner that encourages a general geographic and land use approach (thus greatly facilitating the study of nonstructural measures) while preserving the ability to analyze individual, unique structures should the need arise. This paper discusses the basic concepts of a spatial data management approach to damage appraisals and highlight(s) its integrated use with more traditional individual structure approaches. Selected example results are presented"--Page 2

The U.S. Army Corps of Engineers is using spatial data management techniques in studies that are structured in a manner that requires spatial data management techniques to play a central and dominant role. The Corps of Hydrologic Engineering Center (HEC) provided the basic developmental work on the spatial data management and attendant processing techniques and it is continuing in the role of the basic technology transfer agent. The significant efforts required to document, maintain and service the technology and provide ready consultation service reported herein were planned for during the developmental efforts and are currently being centrally managed to encourage smooth adoption of the techniques by Corps field offices. (Author).

Flood control and flood plain management investigations using spatial data management techniques are increasing in the Corps of Engineers. Pilot studies initiated in the mid-1970's were successful in consolidating analysis concepts, fostering the development of spatial data file creation and management technology and enhancing the consideration of existing and alternative future development patterns in Corps' planning studies. Over 30 studies using HEC-SAM, the Corps' spatial data management system, are now completed or underway. HEC-SAM was created through selective acquisition of commercial software, adaption of academic research products, and development by researchers at the Corps' Hydrologic Engineering Center (HEC). The HEC role continues to be that of system developer and technology transfer agent. The evolution, present capabilities, and applications of HEC-SAM are described. Observations are offered on spatial technology development, implementation, and servicing. (Author).

Spatial-data management techniques allow convenient, cost-effective representation of the spatially-varying data that are necessary for effective water and related-land resources planning. Application of the techniques began in the U.S. Army Corps of Engineers in the early 1970's as an experiment. Since then, the techniques have been used for regional planning studies, major flood-control studies, and limited-scope investigations. The HEC-SAM software, developed and supported by the staff of the Hydrologic Engineering Center (HEC), has made practical these applications. Keywords: Geographic information systems; Data bases.

A two-dimensional horizontal finite element numerical model (RMA-2) was applied to a 15 mile (24 km) river channel-floodplain reach in West Germany. Previous applications of such models have been restricted to much smaller scales. The results indicate that finite element schemes may successfully estimate river stage in large scale floodplain applications. Computed stage hydrographs compared well with observed data using loss coefficients within expected ranges. Two-dimensional flow models have been applied to certain classes of river channel problems. Applications have included detailed analyses of flow patterns near structures such as bridges and floodplains. In all these problems the scale of interest has been small, e.g. reaches of river a few river widths long. Many estuary studies have been done that were of large scale; some of these utilized a hybrid (numerical plus physical) modeling technique. In a review of the application of finite element methods to river channels, Samuels reported that the river channel was resolved separately from the floodplain in only two studies. Missing in previous work is attention to large scale floodplain modeling. The work reported in this paper focuses on the feasibility and accuracy of applying a two-dimensional flow model to a large floodplain. Traditional floodplain studies have used semi-empirical flow routing with steady, one-dimensional computation of water surface elevations to define inundated areas. Keywords: Army Corps of Engines. (kr).

The Corps' Hydrologic Engineering Center (HEC) has developed a generalized simulation model capable of analyzing complex river-reservoir systems. The development of the model, 'HEC-5, Simulation of Flood Control and Conservation Systems' (Eichert, 1974, 1975) has been paced by the changing mission of the Corps as well as the evolution of computer systems. HEC-5 development and management, including code development, testing, documentation, training and field application experience, is discussed. (fr).