Publications report on effects of bedrock geology on stream base flow

NCASI and its member companies have been involved in multiple collaborative studies investigating responses of water flow and water quality in headwater catchments to forest management practices. 

In mountainous regions, bedrock geology can have a dominant influence on water flow dynamics. Yet, few studies have characterized how the effects of bedrock permeability, the geologic property affecting water movement through rock, on the partitioning, storage, and release of water, vary with catchment size.

Recently, two papers addressing these topics were published in Water Resources Research. The research was conducted in 15 nested catchments in western Oregon, half within the HJ Andrews Experimental Forest and half at the site of the Alsea Watershed Study Revisited which is supported by NCASI and others (for more information see 

One of the two papers addresses how bedrock permeability controls stream base flow transit times and how transit time varies with catchment size. The publication reports that “similar catchment forms and hydrologic regimes hide different subsurface routing, storage, and scaling behavior—a major issue if only hydrometric data are used to define hydrological similarity for assessing land use or climate change response.” Authors were V. Cody Hale of Nutter and Associates, Inc., a consulting firm in Athens, Georgia, and Jeffrey J. McDonnell of the University of Saskatchewan. Both authors were associated with Oregon State University at the time of the study. 

The second paper discusses how the influence of different water storage zones (e.g., soils, bedrock) on stream base flow transit times varies with catchment area. Authors include V. Cody Hale (Nutter and Associates, Inc.), Jeffrey J. McDonnell (University of Saskatchewan), Michael K. Stewart (Aquifer Dynamics and GNS Science), D. Kip Solomon (University of Utah), Jim Doolitte (USDA Natural Resources Conservation Service), George G. Ice (NCASI, retired), and Robert T. Pack (Utah State University). They conclude that their “discrete storage zone concept is a process explanation for the observed scaling behavior of Hale and McDonnell (2016), thereby linking patterns and processes at scales from 0.1 to 100 km2.”

Dr. Robert J. Danehy is managing NCASI involvement in research conducted as part of the Alsea Watershed Study Revisited.  

Contact information 



Hale, V.C., and J.J. McDonnell. 2016. Effect of bedrock permeability on stream base flow mean transit time scaling relations: 1. A multiscale catchment intercomparison. Water Resources Research 52:1358-1374.