Estimation of magnitude and frequency of floods in urban basins in Missouri

Abstract

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Magnitude of flood flows for selected annual exceedance probabilities in Rhode Island through 2010

“…As previously mentioned, IMPERV was not a statistically significant explanatory variable at the 95-percent confidence level for any of the exceedance probabilities examined. Despite this lack of significance in this analysis, other studies (Robbins and Pope, 1996;Southard, 2010;Gotvald and Knaak, 2011) found that imperviousness is an important predictor of the magnitude of flood flows. The exploratory statistical analysis done in this study indicated that IMPERV provided some explanatory power, generally ranking fifth or sixth among the variables examined.…”

“…The reason for this is that, during large storms, soils become saturated, preventing further infiltration; this causes surface runoff to increase similar to the effect an impervious surface has for any size storm. Nevertheless, urban adjustments to regionalized flood flow equations for rural basins have been made to include some measure of urbanization, such as impervious surface (Southard, 2010), population density (Watson and Schopp, 2009), or composite urban indices, such as the basin development factor, which accounts for impervious surface as well as storm sewers, culverts, and stream channel alterations (Sauer and others, 1983;Sherwood, 1994).…”

Theoretical link between rainfall and flood magnitude

“…Study of other regions with these methods is warranted. Until this is done and the realism of the predictions improved, empirical methodologies for peak discharge estimation (e.g., Soong, Ishii, Sharpe, & Avery, ; Southard, ) will be superior for planning purposes. Nevertheless, only the comparison of theoretical predictions to observations can provide fundamental insight into the nature of hydrologic processes.…”

Flood-inundation maps and wetland restoration suitability index for the Blue River and selected tributaries, Kansas City, Missouri, and vicinity, 2012

“…Huizinga (2007) updated the two-dimensional model of a 2-mile reach developed by Kelly and Rydlund (2006) in a subsequent study to simulate the potential effects of channel modifications and a proposed grade control structure in the Blue River. Southard (2010) developed regression equations to determine the magnitude and frequency of floods in urban areas in Missouri that included Blue River, Indian Creek, and Brush Creek by using streamgage records in the development of these equations. These regression equations, for which drainage area and percent impervious area are explanatory variables, were used to compute flood streamflows for the 50-, 20-, 10-, 1-, and 0.2-percent AEP flows at the study streamgages (table 2).…”