Lecture 1 - Introduction Flashcards
Define “watershed”
area of land that would drain surface water towards specific point on landscape or on stream/watercourse, also called catchment, fundamental spatial unit/control volume used to conduct hydrological analysis, can range in size
What is delta S for a watershed?
soil moisture storage and surface water impoundments (=0 if annual time step)
What is delta S for a lake?
depends on stage-storage and stage-discharge relationships for the system
What is a stage-discharge relationship?
defines relationship between water level in system and outflow rate, need to identify type of control structure (engineered or natural)
Why are water years used and not regular calendar years? What is typical water year?
snow needs to melt in same year that it snowed in, october to september
What is evaporation?
phase change of liquid water to vapour from open water surfaces
What is transpiration?
ohase change of liquid water to vapour and movement into atmosphere through plant stomata
What is evapotranspiration?
combination of evaporation and transpiration
What does groundwater represent for watersheds?
water recharging deeper geologic systems not connected to surface water
What does groundwater represent for lakes?
water entering or leaving lake through groundwater system, quantification requires field measurements
What is runoff for watersheds?
water leaving watershed as surface water flow
What is runoff for lakes?
water entering lake through a surface water feature
What is baseflow?
dry weather flow, typically originates from groundwater or lakes/reservoirs, significant flow mechanism in perennial streams (year-round)
What is interflow?
lateral flow of water through unsaturated zone to stream
What is the baseflow index?
baseflow/total streamflow
What is drainage density?
total length of streams/catchment area
What is bifurcation ratio?
related to stream order, ratio of number of streams within successive stream order categories (eg # of 1st order streams/# of 2nd order streams)
Explain stream order/Strahler number using an example.
stream with no tributaries=1st order, meeting of 2 1st order tributaries iniates 2nd order stream and so on, correlated with watershed characteristics
What is a hyetograph?
time series of precipitation amounts
What is a hydrograph?
time series of streamflow/discharge
What constitutes climate data? Where can you find climate data?
precipitation, temperature, evaporation, solar radiation, wind speed, relative humidity, find at environment and climate change canada (ECCC)
What constitutes hydrometric data? Where can you find hydrometric data?
discharge, level (stage), find at Water Survey of Canada
What factors do you need to ensure are similar when prorating discharge? Why do we prorate discharge?
area, climate, topography, surface water storage, soils/geology, to transfer discharge records from gauged to ungauged watersheds
