DonAdj: Donor adjustment candidates & results

In UKFE: UK Flood Estimation

Donor adjustment candidates & results

Description

Provides donor adjustment candidates, descriptors, and results in order of the proximity to the centroid of the subject catchment.

Usage

DonAdj(CDs = NULL, x, y, QMEDscd = NULL, alpha = TRUE, rows = 10, d2 = NULL)

Arguments

CDs	catchment descriptors derived from either GetCDs or CDsXML
x	catchment centroid easting (for when CDs isn't used)
y	catchment centroid northing (for when CDs isn't used)
QMEDscd	QMED estimate for the catchment of interest (for when CDs isn't used)
alpha	logical argument with a default of TRUE. If FALSE the exponent of the donor adjustment equation is set to one
rows	number of sites provided; default is 10
d2	a numeric vector of length two; the two site references for the donor catchments chosen for the two donor case

Details

When d2 is FALSE the results for single donor adjustment are in the final column headed 'QMED.adj' for each site. If alpha is set to FALSE, the results in this column are from the same donor equation but with an exponent of 1. The donor adjustment method is as outlined in Science Report: SC050050 - Improving the FEH statistical procedures for flood frequency estimation. The method for two donors is outlined in 'Kjeldsen, T. (2019). Adjustment of QMED in ungauged catchments using two donor sites. Circulation - The Newsletter of the British Hydrological Society, 4'. When two donors are used, only the result is returned, rather than donor candidates. The QMEDfse column provides the gauged factorial standard error for the median of the annual maximum sample. It is worth considering this when choosing a donor site (a high value indicates a poor donor). When choosing between two donors, the site with a lower QMEDfse would be an appropriate choice (all else being equal). The QMEDfse is calculated with the QMEDfseSS() function.

Value

A data.frame with rownames of site references and columns of catchment descriptors, distance from subect site, and associated results. When two donors are used, only the resulting adjusted QMED is returned

Author(s)

Anthony Hammond

Examples

#Get some CDs and output candidate donor sites
CDs.54022 <- GetCDs(54022)
DonAdj(CDs.54022)
#Get results with inputs of x,y, and QMEDscd
DonAdj(x = 283261, y = 288067, QMEDscd = 17.931)
#Get a result with two donors
DonAdj(CDs.54022, d2 = c(54092, 54091))

UKFE documentation built on Nov. 6, 2023, 1:07 a.m.