BEGIN:VCALENDAR
VERSION:2.0
PRODID:icalendar-ruby
CALSCALE:GREGORIAN
X-WR-CALNAME:ESS University Oral Examination: Zach Perzan\, October 16 @ 1p
 m
X-WR-TIMEZONE:Pacific Time (US & Canada)
BEGIN:VEVENT
DTSTAMP:20260513T164501Z
UID:tag:localist.com\,2008:EventInstance_44472620741091
DTSTART:20231016T200000Z
DTEND:20231016T210000Z
DESCRIPTION:Stanford University\n\n*** Ph.D. Thesis/ Oral Defense ***\n\nSu
 rface water-groundwater interactions during extreme floods: hydrologic and
  biogeochemical controls on water quality\n\n \n\nZach Perzan\n\nMonday\, 
 October 16\, 1:00 pm \n\nGreen 365\n\nDepartment of Earth System Science\n
 \nAdvisor: Dr. Katharine Maher  \n\n \n\n \n\n \n\nIn both natural and hum
 an-impacted ecosystems\, floods play a pivotal role in shaping our environ
 ment. In natural systems\, floods replenish groundwater and support ripari
 an habitats. In intensively managed environments\, engineered floods have 
 become a valuable tool for mitigating the effects of global change. During
  flood managed aquifer recharge (flood-MAR)\, for example\, water managers
  intentionally inundate working landscapes in order to replenish depleted 
 aquifers. Both natural and engineered floods deliver an influx of water an
 d reactive species into the subsurface\, triggering a complex web of hydro
 logic and biogeochemical processes that can mobilize nutrients and contami
 nants\, impacting water quality. Through a combination of modeling and dat
 a science approaches\, my research sifts through this complexity and seeks
  to understand the fundamental drivers of surface and groundwater quality 
 during extreme floods. In my first chapter\, I examine the impact of seaso
 nal floods on redox cycling in heterogeneous floodplain aquifers. Through 
 stochastic reactive transport simulations\, I show that the hydrogeologic 
 properties of a floodplain often exert a stronger control on redox conditi
 ons than do biogeochemical reaction rates. In subsequent chapters\, I iden
 tify controls on the movement of water and solutes through the subsurface 
 during flood-MAR. Using high-resolution hydrogeophysical data and  hydrolo
 gic simulations\, I find that tension-driven flow within the vadose zone d
 raws recharge water away from coarse-grained flow paths and traps it in le
 nses of fine-grained sediment. These fine-grained sediments can take years
  to drain following inundation\, limiting recharge efficiency. In my final
  chapter\, I pair hydrologic simulations with Lagrangian particle tracking
  to investigate contaminant transport during flood-MAR. Results reveal tha
 t recharge water applied at the surface takes decades to reach the water t
 able\, during which time some contaminants may be removed through biogeoch
 emical reactions. Overall\, my work deepens our understanding of subsurfac
 e hydrologic and biogeochemical processes during inundation and provides a
 ctionable insights for sustainable water resource management in a changing
  climate.
GEO:37.426823;-122.174006
LOCATION:Green Earth Sciences Building\, 365
SUMMARY:ESS University Oral Examination: Zach Perzan\, October 16 @ 1pm
URL;VALUE=URI:https://events.stanford.edu/event/ess_university_oral_examina
 tion_zach_perzan_october_16_1pm
CATEGORIES:PhD Defense
END:VEVENT
END:VCALENDAR