LWI Region 3 Modeling Overview

Calibration

GAGE NETWORKS (C_5.2) { Five USACE stage-only gages in the Bayou Cocodrie Watershed were used for model calibration, depending on data availability, as shown in the Mapbook. { Gages with significant data gaps for specific events were excluded from calibration for those events. CALIBRATION METHODOLOGY { Calibration used seven events (plus two validation events) ordered by increasing complexity, ranging from low flow/no pumping to high-intensity rainfall with pumping and gate closures (Table 3-8). { Initial soil saturation (Initial Deficit) was a key calibration parameter; four model geometries were created to simulate varying soil conditions: dry, 50%, 75%, and fully saturated. LEARN MORE: C_5, C_5.2, C_5.3 +

Figure 3-38: Major drainage network, IC Points, and Boundary Condition Lines available in Bayou Cocodrie Watershed.

Table 3-8 Modeled rainfall events .

EVENT

PURPOSE

TYPE

DESCRIPTION

Hurricane Gustav – major flooding observed in Region 3, with rainfall totals of up to 10 inches. Rain gages with the most rain in Region 3 show higher accumulated rain in May 2009. Nov 10, 2009, is one of the highest recent events recorded at the Ouachita River gage at Monroe, with a stage of 47.8 ft.

September 2008 Calibration Short

Calibration Short

May 2009

Multi Backwater

September 2009 Calibration

Calibration Short

Major flooding in Bayou Cocodrie in January 9-10, 2013.

January 2013

Major flooding in Region 3 with over 20 inches of rainfall recorded in multiple locations.

Validation Short

March 2016

Short/Low Flow Multi Backwater

September 2016 Calibration

Low flow event defined as a nearly bank-full flow event.

March 18, 2018, is one of the highest recent events recorded at the Ouachita River gage at Monroe.

Calibration

February 2018

37

Hydrologic and Hydraulic Modeling Methodology