CZO

Southern Sierra CZO: snowline processes

CZO

Water balance instrument cluster

Southern Sierra CZO

Southern Sierra CZO team

Principal investigators

Roger Bales, UC Merced

Beth Boyer, UC Berkeley

Martha Conklin, UC Merced

Mike Goulden, UC Irvine

Jan Hopmans, UC Davis

Dale Johnson, U Nevada Reno

Jim Kirchner, UC Berkeley

Christina Tague, UC Santa Barbara

Carolyn Hunsaker, USFS-PSW

Research team

9 students, TBD

Field hydrologist/geochemist

Data manager

Education/communications scientist

Cooperating investigators & students, TBD

Proposed research investigations

1. water cycle & response to perturbations: rain vs. snow dominance, baseflow response, soil moisture, ET & snow patterns/responses

2. coupled hydrologic & (bio)geochemical processes/cycles: soil moisture controls on C/N cycles, weathering & landscape evolution

3. extreme hydrologic events in hydrologic & biogeochemical cycles: linking weathering & nutrient fluxes to fire/rain/snowmelt

4. vegetation control over fluxes of water & nutrients: linking ET, synthesis, respiration to soil moisture & water cycle

5. pathways for transport of water, heat & mass: subsurface pathways, role of meadows, nutrient response to rain vs. snowmelt

6. role of seasonal snowpack in determining critical zone processes: role of snowpack (duration) in N cycling & weathering

Education: train YI instructors & bring more CZ science into their curriculum – about 13,000 middle/high school students cycle through YI 3-5 day courses in the Sierra Nevada annually (near UC Merced)

Gradients in hydrology & geochemistry

Cumulative discharge for 3 catchments, water year 2004

Major ions in streamwater

Southern Sierra CZO measurements

KREW measurements by PSW

stream stage & discharge

stream channel

stream condition inventory

stream physical habitat survey

erosion & sedimentation

geology

soils & litter

shallow soil water chemistry

snowmelt & rain chemistry

stream water chemistry

riparian & upland vegetation

fuel loading

stream invertebrates

algae & periphyton

Instrument grant & CZO additions

flux tower, eddy correlation

snow depth

soil moisture

sap flow

cosmogenic nuclides

high-frequency, high-resolution stream temperature

water levels, piezometersstable isotopescarbon & nitrogen cycling

Digital library: https://eng.ucmerced.edu/snsjho/

KREW is a USFS long-term integrated watershed study

Southern Sierra CZO:snowline processes

Goal: understand how critical-zone processes control fluxes & stores of water across the landscape & how the water cycle modulates

(bio)geochemical, biological, geomorphological & soil processes

Five questions define & focus the core measurements & research: i) how do coupled hydrologic & biogeochemical fluxes vary across the

rain-snow transitionii) what is the role of extreme hydrologic events in water &

biogeochemical balancesiii) to what extent does vegetation modulate or actively control the

primary subsurface fluxes of water & nutrients, vs. act as a passive agent

iv) over what time & space scales, & during what seasons, are macropores & other short-circuit pathways dominant in the critical zone

v) how does the presence of a seasonal snowpack affect soils, geomorphology, biogeochemistry & hydrology in Sierra watersheds & hillslopes, & how will the relevant processes & reservoirs respond as the climate warms & snowpacks recede

Instrument sites

soil moisture, snow, sap flow

Soils grid

Sediment grid

Vegetation grid

Riparian transects