A graphical non-parametric hydrologic alteration test using flow duration curves

• Published in: Hydrological sciences journal Vol. 68; no. 15; pp. 2154 - 2168
• Main Authors: Mowafy, Mohamed H., Kroll, Charles N., Vogel, Richard M.
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 18.11.2023; Taylor & Francis Ltd
• Subjects: Climatic data; Dams; false discovery rate; field significance; Flow duration; flow duration curve; Flow duration curves; High flow; hydrologic alteration; Hydrologic regime; Low flow; median; non-parametric hypothesis tests; Parametric hydrology; Quantiles; Stream discharge; Stream flow; streamflow data
• ISSN: 0262-6667; 2150-3435
• DOI: 10.1080/02626667.2023.2248109

Utilizing annual flow duration curves (FDCs), the modified Mood’s median test (MMMT) was applied to quantiles of the median annual FDCs at 122 disturbed sites in the conterminous US. A simple graphical tool based on the MMMT was combined with a false discovery rate multiple comparison procedure to illustrate the field significance of hydrologic alteration over a wide range of streamflow conditions. Hydrologic disturbance was mostly caused by dams, although other forms of alteration were explored. In addition, 249 minimally regulated Hydro-Climatic Data Network (HCDN) sites were investigated to assess regional climatic drivers of hydrologic alteration. Results indicate that dams can have varying effects on the hydrologic regime, but generally impact low flows more often than high flows in the US. At HCDN sites, we observe significant changes to hydrologic regimes in many regions, especially to low and median flows in the upper midwestern and eastern US.