Hydrologic Vulnerabilities and Risk in the San Jose Watershed

R.D. (Dan) Moore PhD PGeo1

Georg Jost PhD1

Russell Smith PhD2

1 Departments of Geography and Forest Resources Management

The University of British Columbia2 WaterSmith Consulting

Vulnerabilities (1)

• complex hydrology– wetlands– evaporation is a significant fraction of

precipitation

05

1015

Mean daily flow SAN JOSE RIVER ABOVE BORLAND CREEK

Date

Dis

char

ge [

m3 s1

]

1985 1990 1995 2000

A (partial day)B (ice affected)E (estimated)

Vulnerabilities (2)

• data limitations– limited number of climate stations, snow data– water licenses: measured streamflow less than

actual streamflow by an unknown amount

Risks Associated With Climate Change

• likely decrease in annual flow (but not full consensus among models)

• changes to timing of runoff– higher flows in winter and early spring– earlier peaks in spring– lower flows through summer/autumn

Take-home messages

• current water availability not well known• water availability in growing season will

decrease due to– increased evapotranspiration– earlier snowmelt