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Deficit and Constant Loss Infiltration Method and Parameter Estimation

The Deficit and Constant Loss Infiltration Method can be implemented in HEC-HMS, HEC-RAS (2D rain-on-grid), and InfoWorks to account for precipitation loss through infiltration and percolation. In order to facilitate…

Modified Rational Method Application in HydroCAD and XPSWMM

HydroCAD and XPSWMM have the modified rational method built into the programs and it is very convenient to apply the method in either of the modeling tools. One or more…

Rational Method and Modified Rational Method – Peak Flow and Hydrograph

For small drainage areas, the rational method is widely used to calculate peak flows of different drainage design levels to size storm sewer, inlets, culverts, and ditches. The rational method…

NRCS Rainfall Distributions Based on NOAA Atlas 14 Precipitation Depth and Duration

NOAA Atlas 14 provides the latest official U.S. precipitation frequency, depth and duration data. Visit this post to learn more about how to retrieve and utilize NOAA Atlas 14 data.…

PMP and PMF for Design by HEC-MetVue and HEC-HMS (2 of 2)

This post is to explain how to set up an HMR 52 storm in HEC-HMS by using HEC-MetVue PMS parameters and how to optimize it by setting a objective goal…

PMP and PMF for Design by HEC-MetVue and HEC-HMS (1 of 2)

Probable maximum precipitation (PMP) is theoretically the greatest precipitation for a given duration that is physically possible over a given size storm area at a particular geographic location. Probable maximum…

Objects and Variables in Python

In Python, everything is an object, such as int, float, string, list, tuple, dictionary,... When you assign a value to a variable, you basically create an object with a reference…

XPSWMM Confusions and Clarifications (2 of 2)

XPSWMM is a popular 1D and 2D hydrologic and hydraulic modeling tool developed by Innovyze. Though originally XPSWMM was designed primarily to model storm sewer network system, it has gained…