Hillslope and Watershed Hydrology FE 537 Syllabus Fall 2004 Four ...

infiltration model with a method for moving soil moisture downslope either by attempting to
trace topographically controlled flowpaths with a local Darcy flux or developing a conceptual
redistribution scheme (e.g. Topmodel).
During this time, a new set of scientific questions have evolved, separate in focus and
intermediate in scale to traditional agricultural and water resources engineering. These dealt with
problems in non-point source contaminants, acid rain, and other integrated watershed hydrologic
processes and required a fuller understanding of the vertical distribution of flowpaths through
hillslopes, their velocities and residence (or contact) times, and temporal dynamics on storm to
seasonal time scales.Partially in response to these emerging problems, in the 1980s and 1990s,
catchments (both hillslopes and streams) have been intensively studied by simultaneously
monitoring the distribution and flux of water and chemicals at many locations in space and time.
Technical advances in methods of measuring soil water distribution in the soil profile (TDR),
soil and substrate structure (ground penetrating radar), and the use of chemical and isotopic
tracers to source streamwater during this time have dramatically increased the amount of
information available to study basic processes by which water moves through hillslopes. The
information is not consistent in certain cases, between isotopic and chemical signals, with signals
derived from more standard hydrometric methods.
As our ability to measure hillslope flowpaths and the evolution of soil moisture patterns and
chemistry progressed, it was recognized that the concept of matrix flow as the dominant
subsurface pathway may not be universally applicable. It is now recognized that the process of
macropore flow and other preferential flowpaths through hillslopes are significant at least under
certain conditions. Over the last 10-15 years, their has been a rapid advance in our ability to
observe distributed processes in watersheds over a range of scales. The intensive monitoring of
catchments has been made possible by automatic sampling and remote sensing techniques. The
advent of isotopic methods to study the source and evolution of stormwater have added
significantly to our knowledge base, sometimes yielding information that appears to conflict
with previously held concepts and more traditional hydrometric data collection methods. These
observations have raised many questions and issues about all of our commonly held concepts of
streamflow generation and soil water dynamics.
Current model development continues to seek to incorporate the distribution and dynamics of
soil moisture and the set of possible flowpaths that become important under given conditions.
However, at present there does not appear to be either a general understanding or consensus on
how the dominant processes of water input, internal flow (pathway dynamics) and outflow
(including evapotranspiration) interact and evolve on different hillslopes. At the same time, an
understanding of these processes and their interactions have become critical to a set of pressing
scientific questions regarding flood generation, water supply, water quality and land/atmosphere
interactions. This course will explore the state of the art of Hillslope Hydrology as it forms the
foundation of the many water-mediated reactions that relate to it in the context of contemporary
environmental problems.
Learning Objectives of the Course: