Flow prediction accuracy given DEM resolution

Model accuracy for snow-rain transition watersheds was more sensitive to DEM resolution than for snow-dominated watersheds.

Model accuracy for watersheds with steep slopes was more sensitive to DEM resolution than for watersheds with mild slopes.

Model accuracy in general is higher for snow dominated watersheds. K.Son, Tague. C and , Hunsaker, C.T, (in prep) Effect of spatial resolution of DEM on ecohydrologic predictions and its sensitivity to climate variability in Sierra mountain catchments, Water resources Research.

Soil parameter uncertainty effectvs. climate warming effect

TMS(P301)

SMS(B203)

Soil parameter uncertainty effect was larger than climate warming effect.The climate warming effect was larger in the wetter climate conditions K. Son and Tague, C. (in prep) Importance of soil parameter uncertainty in assessing climate change projections in small two Sierra watersheds,

Water resource research

Calibrated RHESSYs model

Generated Spatial and temporal values of snow, soil moisture and transpiration

Snow Soil moisture

Transpiration

Clustering analysis (PAM algorithm)

Hydrologic Similarity indices (HSI)

Finding Clusters and Medoids Sampling Recalibrated model

Snow, Soil moisture, Transpiration,

ET and Streamflow

Hydrologic Similarity indices (HSI)mean and inter-annual variation (expressed

as coefficient of variation, CV) of five indicators

(1) Day of water year that snow melts completely (2) Number of days that root-zone soil

moisture is fully saturated (3) Number of days that root-zone soil

moisture declines to 70% of saturation

(4) Number of days that root-zone soil moisture declines to 50% of saturation

(5) Day of water year that transpiration declines to 50% of its peak growing season value

What are strategic soil moisture sampling design to represent the impact of climate variability on soil moisture and vegetation water use in snow-dominated watersheds?

Validation of sampling design

Combining all indices represent elevation difference and the flow drainage pattern. Model-based clusters reproduced general spatial pattern of observed soil moisture. K.Son, Tague, C. (in prep) Strategic sampling microclimate, soil moisture and sapflux for improving ecohydrological predictions

of the Sierra Mountain watersheds., Hydrological Processes

C2

C3

C4

C5

C6C1

With a warmer climate (+3°C) and no change in precipitation – we get increased water demand (Forest ET/NPP should stay the same or increase) – but also a shift in timing (ET/NPP might go down because more winter P is lost as runoff )

Note that the effect of timing occurs across all P, but is greater in wetter years, but also biggest increases occur in the wettest years

Precip PkSwe Interaction

Cont

rol o

n ET

(reg

ress

ion)

Soil parameter uncertainty changes strength of relationships - but not conclusions about importance of precipitation, timing, and their interaction

Tague, C., and H. Peng (2013), The sensitivity of forest water use to the timing of precipitation and snowmelt recharge in the California Sierra: Implications for a warming climate, J. Geophys. Res. Biogeosci., 118, doi:10.1002/jgrg.20073

For all patches, all years, change in ET

Chan

ge in

ET

(war

min

g) (m

m/y

r)