Regional skew coefficients are necessary to determine flood frequency following Bulletin 17C guidelines. The goal of FFA_regional-skew is to estimate a regional skew coefficients for stream gages in the Northwestern Great Plains and northern portion of the High Plains sections of the Great Plains within southeastern Montana, eastern Wyoming, northeastern Colorado, and the western portions of Nebraska and the Dakotas.
The study area encompasses the Northwestern Great Plains and the northern portion of the High Plains ecoregion. Northwestern Great Plains ecoregion encompasses the Missouri Plateau section of the Great Plains in southeastern Montana, northeastern Wyoming, and the western portion of the Dakotas. The northern portion of the High Plains ecoregion encompasses southeastern Wyoming, western Nebraska, eastern Colorado, and western Kansas (http://www.cec.org/files/documents/publications/10415-north-american-terrestrial-ecoregionslevel-iii-en.pdf).
The study area is a dry mid-latitude steppe climate marked by hot summers and cold winters, and a mean annual temperature varying by latitude.
# Make a map
# Here is some example code:
# https://www.r4wrds.com/intro/m_intro_mapmakingEcoregion membership was identified as a key predictor of hydrologic similarity in south-central South Dakota (Tinant, PhD dissertation).