RUNOFF HYDROGRAPHS FOR MATHEMATICAL WATERSHED MODEL

A MATHEMATICAL MODEL OF THE CHANNEL SYSTEM OF A 21.35 SQUARE MILE WATERSHED WAS DEVELOPED. THE PARTIAL DIFFERENTIAL EQUATIONS OF MOMENTUM AND CONTINUITY WERE EXPRESSED IN FINITE DIFFERENCE FORM, AND USED TO ROUTE THE UNSTEADY FLOW THROUGH THE CHANNEL SYSTEM, YIELDING OUTFLOW HYDROGRAPHS. RAINFALL EXCESS IN VARIOUS RATES AND DURATIONS WAS USED AS THE INPUT TO THE MODEL. ALL OF THE HYDROLOGIC TIME PARAMETERS WHICH WERE EVALUATED FROM THE MODEL OUTPUT VARIED WITH THE SUPPLY RATE. IF THE RESPONSE OF THE WATER- SHED MODEL CAN BE CONSIDERED REPRESENTATIVE OF A NATURAL WATERSHED, NONE OF THE PRESENTLY DEFINED TIME PARAMETERS SHOULD BE CONSIDERED CONSTANTS FOR A GIVEN WATERSHED. THE TIME TO VIRTUAL (97 PERCENT OF) EQUILIBRIUM VARIED INVERSELY AS THE 0.23 POWER OF THE SUPPLY RATE. THE PEAK-FLOW RATES SHOWED A NONLINEAR RELATIONSHIP TO RUNOFF AMOUNT FOR A GIVEN DURATION. PEAK DISCHARGES OBTAINED WITH THE MODEL WATERSHED DO NOT SUPPORT THE UNIT-HYDROGRAPH PRINCIPLE BUT ADD TO THE EXISTING EVIDENCE OF RUNOFF NONLINEARITY. /ASCE/

• Supplemental Notes:
  • Vol 94, No HY 6, PROC PAPER 6248, PP 1453-1474, 7 FIG, 5
• Authors:
  • Machmeier, R E
  • Larson, C L
• Publication Date: 1968-11

Media Info

• Serial:
  • Journal of the Hydraulics Division
  • Publisher: American Society of Civil Engineers

Subject/Index Terms

• TRT Terms: Finite differences; Hydrographs; Hydrology; Mathematical models; Partial differential equations; Rainfall; Runoff; Watersheds
• Old TRIS Terms: Flow value
• Subject Areas: Highways; Hydraulics and Hydrology;

Filing Info

• Accession Number: 00204194
• Record Type: Publication
• Files: TRIS
• Created Date: Jan 31 1994 12:00AM