UKFE (version 1.0.2)

QMEDDonEq: QMED donor adjustment

Description

Applies a donor adjustment to the median annual maximum flow (QMED) estimate

Usage

QMEDDonEq(
  AREA,
  SAAR,
  FARL,
  BFIHOST,
  QMEDgObs,
  QMEDgCds,
  xSI,
  ySI,
  xDon,
  yDon,
  alpha = TRUE
)

Arguments

AREA

catchment area in km2 for the site of interest

SAAR

standardised average annual rainfall in mm for the site of interest

FARL

flood attenuation from reservoirs and lakes for the site of interest

BFIHOST

the baseflow index as a function of soil type for the site of interest

QMEDgObs

the observed QMED at the donor site

QMEDgCds

the QMED equation derived QMED at the donor site

xSI

the catchment centroid easting for the site of interest

ySI

the catchment centroid northing for the site of interest

xDon

the catchment centroid easting for the donor site

yDon

the catchment centroid northing for the donor site

alpha

a logical argument with a default of TRUE. When FALSE the exponent in the donor equation is set to one. Otherwise it is determined by the distance between the donor and the subject site

Author

Anthony Hammond

Details

Although a single donor adjustment can be applied with the DonAdj() function and the QMED() function, this additional function is provided for flexibility. The method is that of Science Report: SC050050 - Improving the FEH statistical procedures for flood frequency estimation (2008). The x and y grid reference inputs assume that the grid references for subject and donor site are using the same grid referencing system.

Examples

# Get observed QMED for site 15006
q_ob <- median(GetAM(15006)[, 2])

# Get QMED equation estimated QMED for the donor site
q_cd <- QMED(CDs = GetCDs(15006))

# Display CDs for site 27051 & note the easting and northing
GetCDs(27051)

# Display CDs for site 15006 & note the easting and northing
GetCDs(15006)

# Apply the QMEDDonEq function with the information gained
QMEDDonEq(
  194, 1096, 0.955, 0.297, q_ob, q_cd,
  xSI = 289289, ySI = 947523,
  xDon = 280908, yDon = 953653
)