A topographically-driven flow system is one in which groundwater flows from higher-elevation recharge areas, where hydraulic head is higher, to lower-elevation discharge areas, where hydraulic head is lower.
In this setting, the main factors controlling groundwater flow are basin geometry, shape of the water table, and the distribution of hydraulic properties.
The user selects the basin length, draws the topographically controlled water table, selects a mesh density for calculation, draws regions of hydraulic conductivity on the mesh, clicks a button to draw hydraulic head lines, then chooses whether to draw flow lines or to track particle movement, both of which can be animated with time. Time is indicated below the cross section.
The TopoDrive software was created by Paul Hsieh in 2001 for the USGS and updated by Hsieh in 2020 to function on modern web browsers. A discussion of TopoDrive is provided in the Groundwater Project PDF book “Graphical Construction of Groundwater Flow Nets” (or read Section 2.9 online “Create and Investigate Topographically Driven Flow Systems”). Also, the PDF book “Introduction to Karst Aquifers” uses the software in Exercise 6 that you can access at this read-online link. A Groundwater Project YouTube video demonstrates how to use TOPODrive.
Citation: Hsieh, P. (2020). Flow Systems: TOPODRIVE – Topographically Driven Groundwater Flow. An Interactive Educational Tool of The Groundwater Project, Guelph, Ontario, Canada.