Unsaturated zone processes control the amount and the quality of water that goes to plant growth and to ground- and surface-water supplies. Water arrives at the land surface from a variety of sources—rainfall, irrigation, snowmelt, and ponded or flowing surface water. The partitioning of this water among different media and processes within the unsaturated zone determines how much becomes soil moisture, aquifer recharge, atmospheric vapor, overland flow and subsurface stormflow to lakes and streams.
Highlights:
• Development of a process-level characterization of macropore-flow initiation. This framework has immediate value for discerning the sensitivity of preferential flow to factors like soil wetness and precipitation intensity.
Nimmo, J.R., 2016, Quantitative framework for preferential flow initiation and partitioning: Vadose Zone Journal, v. 15, no. 2, doi:10.2136/vzj2015.05.0079. (PDF).
• Paper and database reporting important hydraulic-property measurements our group has conducted over the last twenty years
Perkins, K.S., and Nimmo, J.R., 2009, High-quality unsaturated zone hydraulic property data for hydrologic applications: Water Resour. Res., 45, W07417, doi:10.1029/2008WR007497. (PDF).
• Investigation of oil moisture dynamics in Hawaii
Perkins, K. S., Nimmo, J.R., and Medeiros, A.C., 2012, Effects of native forest restoration on soil hydraulic properties, Auwahi, Maui, Hawaiian Islands: Geophysical Research Letters,
39:L05405 doi:10.1029/2012GL051120. (PDF) Perkins, K.S., Nimmo, J.R., Medeiros, A.C., Szutu, D.J., and von Allmen, E., 2014, Assessing effects of native forest restoration on soils moisture dynamics and potential
aquifer recharge, Auwahi, Maui, Ecohydrology, DOI:10.1002/eco1469. (PDF).
• Saturated hydraulic conductivity measurement
Nimmo, J.R., Schmidt, K.M., Perkins, K.S., and Stock, J.D., 2009, Rapid Measurement of Field-Saturated Hydraulic Conductivity for Areal Characterization: Vadose Zone Journal, v. 8, no.
1, p. 142-149. (PDF)
Mirus, BB, K Perkins, 2012. Practical estimates of field-saturated hydraulic conductivity of bedrock outcrops using a modified bottomless bucket method, Water Resources
Research, DOI:10.1029/2012WR012053. (PDF).
