MPB Hydrology Flashcards
What is the impact of MPB on streamflow
Billy idol
More water in streams (more water)
Streams respond more quickly (more quickly)
Flood events increase in frequency (more often)
Why does water flow increase after beetle attack
Loss of intercept and evapotranspiration
More snow on ground and snow melt energy
More soil water as a response
What are the potential impacts of hydro changes
Overall volume peaks 15-20% larger
Peaks and low flows change timing
Affects fish, infrastructure, watersheds, agriculture
What is the actual impact of beetle dependent on?
1 weather: Amount of rain and snow and Snowmelt (temperature, wind, rain)
2 watershed responsiveness: soil depth and type, stream density, mid slope roads (intercept soil water)
3 proportion of forest killed by beetle.
How are MPB Effecting hydrology?
Kill vast stands, greatly reducing evapotranspiration and interception while water input from rain and snow remains the same.
A positive feedback is created which causes even faster snowmelt
More soil water, ground water and streamflow.
What are the management options when dealing with hydrologically sensitive areas? ***
Draw graph of cc vs Unsalvaged and explain * TQ
No salvage: accept reduced ET and allow hydrologic recovery. Leave snags and live trees. Degradation will increase, reducing et for a time but new veg will eventually increase it to normal levels.
Salvage: log and plant. Reduce remaining ET from snags, periodically increasing but quicker recovery from planting.
Logging with retention: reduce short term impact of complete salvage and other retention benefits.
What can you do to reduce water flow after harvesting beetle kill.
De build roads to reduce interceptions. Once road is gone you need no culvert or ditches.
Hazard vs risk?
What is the hazard and risks of salvage?***
Hazard (how severe)
Risk ( what is the probability )
Salvage creates initial higher risk but quicker recovery (less risk duration).
