LWI Region 3 Modeling Overview

BOEUF

MACON TENSAS

COCODRIE

4.2.3 Tensas GAGE SELECTION { Six gages are in the Tensas River Watershed (three USGS: Tendal, Southeast of Tendal, and Clayton; three USACE: Transylvania, Newlight, and Fools River). { Gages were selected based on data quality, record length, and backwater influence. Those affected by Ouachita River backwater (Clayton, Fools River, Newlight, Transylvania) were excluded. { Tendal and Southeast of Tendal were selected for analysis and calibration; Figure 4-16 shows all gage locations . LEARN MORE: (T_3.3) a. Rating Curve Development { Figure 4-17 displays an example of a best fit curve developed for the rating curve at the Tendal gage. { Figure 4-18 displays an example of the rating curve used to predict flows at the Tendal gage compared to simulated flows. LEARN MORE: (T_3.4)

b. Gage Analysis HEC-SSP { Peak flows were calculated from USGS stage data using rating curves and analyzed with HEC-SSP, applying Bulletin 17C and the Log Pearson Type III distribution. { At Tendal, stage data was used instead of unreliable flow records; backwater effects were noted in 24 of 89 years but did not affect the analysis approach. { HEC-SSP results were generated for multiple storm events (20%, 10%, 4%, 2%, 1%, 0.5% and 0.2%); Figure 4-19 displays the Tendal gage curve, confidence limits, and observed flow comparison.

LEARN MORE: (T_3.5)

Figure 4-16: USGS and USACE gage locations.

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LWI REGION 3 TRAINING

LOUISIANA WATERSHED INITIATIVE