Optimal Spillway Dimensions for Flood Stage Reduction in the Lower Illinois River with the UNET Model

Yanqing Lian, Misganaw Demissie, Hyun Il Choi, Andres Blanco

Research output: Chapter in Book/Report/Conference proceedingConference contribution


The one-dimensional unsteady flow model UNET was used to study the propagation of flood waves in the lower Illinois River from Peoria to Grafton. The calibrated and verified model was used to simulate water surface elevations along the Illinois River for existing conditions and for managed Levee and Drainage District (LDD) storage options. To further expand the applications of the lower Illinois River UNET model, the model was extended to include Pool 26 of the Mississippi River to resolve the difficulties in handling the backwater effects from the Mississippi River. This model was used to study different managed storage options to develop systematically organized information and tools for managing floods in the lower Illinois River. It was assumed that spillways will be placed on top of the levees to simulate managed flow into selected LDD storage areas along the lower Illinois River. Two LDDs of difference sizes and locations were selected to study the relationship between the peak flood stage reduction and the sizes of the inflow section of the spillways. The study was based on the maximum water surface elevation of a 50-year frequency flood. Study of the optimal spillway widths for fixed depths and optimal spillway depths for fixed widths indicated that the optimal spillway dimensions for peak flood stage reduction vary according to locations and individual flood events.

Original languageEnglish (US)
Title of host publicationWorld Water and Environmental Resources Congress
EditorsP. Bizier, P. DeBarry
Number of pages10
StatePublished - 2003
Externally publishedYes
EventWorld Water and Environmental Resources Congress 2003 - Philadelphia, PA, United States
Duration: Jun 23 2003Jun 26 2003

Publication series

NameWorld Water and Environmental Resources Congress


OtherWorld Water and Environmental Resources Congress 2003
Country/TerritoryUnited States
CityPhiladelphia, PA

ASJC Scopus subject areas

  • Water Science and Technology
  • Aquatic Science


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