Patent ID: 7277837
Filing Date: 2007-10-02
Classification: G01P

Abstract:
1. A computer-implemented method using a computer having a display and a memory for storage of information representative of hydrologic and hydraulic conditions for determining water flow directions based on flow vector values calculated in part with a D8 method applied to a watershed divided into more than one predefined, rectangular major cell each encompassing a minimum of nine predefined, rectangular minor cells including a center minor cell and eight neighbor minor cells wherein the watershed includes one or more types of problem areas identified as depressions, flat areas or peaks each of which extends across more than one major cell and each of which requires fixing and wherein further the number, location and elevation of all minor cells are known as are a maximum depth depression to be corrected, a maximum number of downstream minor cells to check in fixing depressions and peaks, a largest depression area to fix and a largest flat area to fix, comprising: selecting and designating one major cell for which to begin generating flow vector values; creating a buffered array in the memory containing elevation and identification data for all minor cells in the designated major cell and all major cells bordering the designated major cell; calculating flow vector values for each minor cell within the buffered array using the D8 method wherein a flow vector value of zero is assigned to any minor cell located in a problem area for which a flow vector value cannot be calculated using the D8 method; storing in the memory the calculated flow vector values in association with the minor cell to which they relate; checking the flow vector value of each minor cell within the designated major cell until all cells have been checked and all cells having a flow vector value of zero have been found; assigning a problem type in the memory to each minor cell within the designated major cell having a flow vector value of zero; fixing first all minor cells in the designated major cell to which a depression problem type has been assigned wherein depressions are fixed independently and successively from the highest depression to the lowest depression and elevation changes are imposed on minor cells in the buffered array, as required; fixing second all minor cells in the designated major cell to which a flat area problem type has been assigned wherein each flat area is fixed independently and elevation changes are imposed on minor cells in the buffered array, as required; fixing third all minor cells in the designated major cell to which a peak problem type has been assigned wherein peaks are fixed independently and successively from the lowest peak to the highest peak and elevation changes are imposed on minor cells in the buffered array, as required; recalculating and storing in the memory flow vector values for each minor cell within the buffered array using the D8 method wherein a flow vector value of zero is assigned to any minor cell located in a problem area for which a flow vector value cannot be calculated using the D8 method; checking again the flow vector value of each minor cell within the designated major cell until all cells have been checked and all cells having a flow vector value of zero, if any, are found; if any minor cells having a flow vector value of zero have been found, storing in the memory the elevation and flow vector value associated with each minor cell as changed, if necessary; selecting and designating a previously unselected major cell and repeating the process beginning with creating a buffered array; and retrieving the elevation and flow vector value for the watershed stored in the memory to depict on the display at least one of a basin delineation, flowpath tracing, drainage area calculation, the extents of hazardous waste spills and a streamline.