R scripts for design storm analysis

A set of R scripts was developed to help analyze the frequency of rainfall (or storm) events statistically and determine the size of design storms (e.g., 10-year or 100-year storm event). A set of example input and output files can be found with the scripts.

HYSTAR model

Grid-based spatially distributed hydrological modeling became feasible along with advances in watershed routing schemes, remote sensing technology, and computing resources. Such modeling is expected to be common in routine hydrological analysis and watershed management planning as it can maximize the use of spatial information and provide a detailed picture of transport processes. I developed a two-dimensional distributed hydrological model capable of simulating watershed rainfall-runoff process, HYdrology Simulation using Time-Area method (HYSTAR). Example input and output files can be found with the model code written in R.

An Excel-based computational template for irrigation scheduling using dual crop coefficients

An Excel-based computational template was developed to help Extension educators to schedule irrigation for efficient use of water. The dual crop coefficient method is employed to calculate evaporation and transpiration rates separately in the template, expecting more accurate soil water tracking compared to using a single crop coefficient. Using the template, the crop water needs can be conveniently calculated on the basis of soil characteristics, crop growth stages, and weather information. Application examples provided in electronic supplementary material demonstrate that the amount and frequency of irrigation should be adjusted according to soil texture. This tool was published in Journal of Extension: https://tigerprints.clemson.edu/joe/vol57/iss1/3/ 

Calculating the expected probability of having a design storm event

An Excel spreadsheet that demonstrates how to calculate the expected probability of having a design storm event using the binomial distribution.

Irrigation scheduling based on the dual crop coefficient method of FAO56

An Excel spreadsheet for calculating soil water content and ET and determining the timing and amount of watering.

Coordinate transformation from GCS to TM on Bessel Ellipsoid

An Excel spreadsheet for converting coordinates from GCS to TM on the Bessel ellipsoid

Software for frequency analysis: VTFIT developed by Richard Cooke

Using VTFIT, we can find the probability distribution that the best fits rainfall data and estimate the size of a design rainfall. Due to the restrictions on the types of files that can be uploaded, only user manual is provided here; please contact me if you want to try the software.

SCS rainfall types

Comparison of the SCS rainfall temporal distribution types

Green-Ampt calculation of effective rainfall depth

An Excel spreadsheet that demonstrates how to calculate effective rainfall depths using the Green-Ampt equation

USLE erosion calculator

An Excel spreadsheet that demonstrates how to calculate erosion rats using the USLE equation