dartx: Applies Correction Factor to Drainage Area Ratio Calculated...
In mps9506/dartx: Applies Drainage Area Ratio Method With Correction Factors

Description Usage Arguments Details Value References

View source: R/dartx.R

Streamflows estimated using the drainage-area ratio method are typically over- or under-estimated at the tails of the streamflow distribution. Asquith, Roussel, and Vrabel (2006) provide empirically-derived correction factors for estimating streamflows in Texas using the drainage-area ratio method. Applying this function to a dataframe of streamflows will return a dataframe with the original streamflow, the non-exceedance probability (cume_dist), the correction factor used (exp), and the estimated streamflow (Q).

1	dartx(.data, flow, dar, defaultPhi = TRUE, ...)

`.data`	table of class data.frame with at least one column with streamflows
`flow`	Variable specifying streamflows in df
`dar`	numeric, drainage area ratio to be applied
`defaultPhi`	logical. Defaults to `TRUE`. Use `TRUE` to apply values reccomended by Asquith et. al. If `FALSE` provide a dataframe with derived values of phi as a dataframe with the following variables: `min`, `max`, `exp`. Where min and max are the range of percentile values to apply the value of phi and exp is the value of phi to be applied.
`...`	optional arguments. If `defaultPhi = TRUE`, expects a dataframe supplied for the argument `customPhi`.

The drainage area ratio is an algebraic method for estimating same-day streamflows from one location to another on the basis the the ratio of the drainage areas are the same as the ratio of the streamflow. The typical equation is:

Y = X(Ay/Ax)^phi

Where Y is the streamflow at the ungaged site, X is the streamflow at the gaged site, Ay and Ax are drainage areas of Y and X. Often, phi is assumed equal to one.

Asquith, Roussel, and Vrabel (2006) developed empirically derived values of phi based on streamflow percentiles (non-exceedance probability) for 54 percentiles of daily mean streamflow in Texas. Values of phi range from 0.700 to 0.935.

dataframe with new variables: Q_percentile, exp and Q. Where Q_percentile are the non-exceedance probability, exp are the values of phi applied to the DAR calculation and Q is the DAR estimated flow value.

Asquith, William H., Meghan C. Roussel, and Joseph Vrabel. 2006. “Statewide Analysis of the Drainage-Area Ratio Method for 34 Streamflow Percentile Ranges in Texas.” 2006–5286. U.S. Geological Survey Scientfic Investigations Report. U.S. Geological Survey. https://pubs.usgs.gov/sir/2006/5286/pdf/sir2006-5286.pdf.

mps9506/dartx documentation built on Sept. 3, 2019, 9:32 a.m.