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A stream hydrograph is commonly determining the influence of different hydrologic processes on discharge from the subject catchment. Because the timing, magnitude, and duration of groundwater return flow differs so greatly from that of direct runoff, separating and understanding the influence of these distinct processes is key to analyzing and simulating the likely hydrologic effects of ...
Hydrologists make use of this hydrologic budget when they study a watershed. The inputs in a hydrologic budget include precipitation, surface flow, and groundwater flow. Outputs consist of evapotranspiration, infiltration, surface runoff, and surface/groundwater flows. All of these quantities can be measured or estimated based on environmental ...
Computing the total hydrograph Provided the value of A is known, the total hydrograph can be obtained using a successive number of time steps and computing, with the runoff equation, the runoff at the end of each time step from the runoff at the end of the previous time step. Unit hydrograph The discharge may also be expressed as: Q = − dS/dT .
The Hydrologic Engineering Center (HEC) in Davis, California, developed the River Analysis System (RAS) to aid hydraulic engineers in channel flow analysis and floodplain determination. It includes numerous data entry capabilities, hydraulic analysis components, data storage and management capabilities, and graphing and reporting capabilities.
More precisely, it produces a surface runoff hydrograph in response to a rainfall event, represented by and input as a hyetograph. Rainfall-runoff models need to be calibrated before they can be used. A well known runoff model is the linear reservoir, but in practice it has limited applicability.
Each mathematical model included in the program is suitable in different environments and under different conditions. Making the correct choice requires knowledge of the watershed, the goals of the hydrologic study, and engineering judgement. HEC-HMS is a product of the Hydrologic Engineering Center within the U.S. Army Corps of Engineers.
Cartographers can link to or download the NHD to use in their computer mapping software. The NHD is used to represent surface water on maps and is also used to perform geospatial analysis. It is a digital vector geospatial dataset designed for use in geographic information systems (GIS) to analyze the flow of water throughout the nation. The ...
Analysis of the relationship between precipitation intensity and duration and the response of the stream discharge are aided by the concept of the unit hydrograph, which represents the response of stream discharge over time to the application of a hypothetical "unit" amount and duration of rainfall (e.g., half an inch over one hour). The amount ...