Model BathymetryLake Travis: A Sinuous Reservoir

Bridget Wadzuk

March 29, 2001

Introduction

Reservoir Characteristics

ModelsCE-QUAL-W2 (COE)

2-DSegmented bathymetry

ELCOM (Hodges/UWA)3-DCartesian grid bathymetry

Taken from CE-QUAL-W2 V3 User’s Manual

Problem

Bathymetry from ArcView – Cartesian grid (plan view)

Need to get into a format that is accepted by CE-QUAL-W2 (profile view)

STRAIGHTENED

BATHYMETRY

Theory

Relation of physical and radial space1:1 correspondenceRadial lines

Arc lengths

2 2

2 1 2 1 2 10

( , )R s rs s x x y y

R

Easier Said…

Choosing a grid Resolution over scale of Lake Travis

Approach using Matlab Select points for centerline Spline points to a smooth curve Compute normal radial lines Check for crossing of radial lines Repeat process until no crossings Use intervals for bathymetry

Bathymetry (original)

Centerline Points

Radial Lines (1)

Radial Lines (2)

Radius of Curvature, Ro

Channel Width, Normally, / Ro < 1 Ignore curvilinear term in sinuous systems

Unacceptable, / Ro > 1Thalweg must be adjusted

Radial Lines (3)

Straightened Bathymetry

Yet To Come

Change approach to a GIS method

Use a smaller, more concise areaLake LBJLess computationally intensive