BAKWATR—Computation of gradually varied flow

Abstract

The BAKWATR computer program computes profiles of gradually varied flow in open channels of irregular shape using a microcomputer. Channel cross sections are defined by a series of points outlining the channel boundaries, each having a horizontal and vertical coordinate. The program generates tables of area, hydraulic radius and surface width as functions of flow depth. These tables are then used to determine the depth of flow at each defined cross-section by a standard step method. Results are printed in tabular form and include water surface elevation, depth of flow, cross-sectional area, hydraulic radius, velocity and velocity head at each section, and friction and eddy losses in the reach of channel downstream of each section. Application of the BAKWATR program is limited to steady gradually varied flow behavior in subcritical flow regimes. Options are provided for establishing the depth of flow at the control section, as BAKWATR can compute the steady flow depth through rectangular weirs and submerged or unsubmerged circular culverts, or the user may input a known depth at the control section for the given flow rate.