ecological flows Flashcards
what are threats to rivers
habitat alteration
pollution
invasive & nuisance species
Exploitation
Climate change
factors included in biotic index
channel characters
chemical variables
energy sources
flow conditions
biotic interactions
environmental flow definition
flow of water in a natural river or lake sustaining healthy ecosystem AND good & services human derive from them
how to estimate envr flow
By establishing the quality, quantity and temporal distribution of water required to maintain key components, functions & processes of aquatic systems AND ecosystem services to people
-making a societal judgment of how ecosystem should be maintained
water quantity and timing
-not just important to maintain minimum water quantity -> timing matters
-water timing matters a lot: natural high & lows AND natural flood necessary for organisms’ life cycles
managing ecosystems goods & services and lists
based on perception and subjectivity to decide which ones to focus more
list: fisheries, food supply, aesthetic, navigation, ecotourism, etc,
4 considerations to establish envr flow
reference conditions
present ecological state
classification and objectives
assessment of flow patterns
major flow components to account for
riverine ecosystem need flow variability to maintain certain ecological function:
-extreme low flows
-baseflow (low flow)
-high flow pulses
-small floods
-floodplain maintenance flows (large floods)
all have different: magnitude, freq, duration, timing and rate of change
natural VS functional flow regime
functional always below natural flow regime because only meet minimum requirements
when considering envr flow, should consider:
minimum amount of flow and necessary variation in flow regime
-should always be legally, scientifically, administratively defensible
