week 04 - stream Flashcards
1
Q
watershed
A
- land area that drains into a water body
- aka: catchments (rest of world), based on topography
- graphic method for measuring area of watershed: graph paper -> count vertices
- planometer
- GIS
- rod + level
- need to know area for:
- trees, runoff, nutrients per area
- w-shed defines area that delivers water, nut’s, etc
2
Q
who measures watersheds?
A
- USGS, USBoR, USACoE, USFS, NRCS, USFWS…
- omg so many, but not EPA? (which is more regulatory)
3
Q
w-shed assessment methods
A
- hydrology regime, w/ streamflow records
- peak flows
- flow durations
- base flows
- compare w/ precip. data
- assess connectivity changes
- dams, diversions, leveses, impervious areas
- organic matter input processes
- nutrient inputs (point/non-point)
- sediment supply + erosional processes
- light/heat inputs
*
4
Q
what is measured
A
- land cover / use
- physiography (phys. patterns/processes of Earth)
- climate
5
Q
what to know about precipitation
A
- quantity
- intensity (rate)
- temporal variation
- spatial variation
- form (solid, liquid)
6
Q
what to know about stream channels
A
- slope
- width
- type
- substrate
- form
- note engineering vs. ecological views of streams
7
Q
bankfull width / depth
A
- lateral extent of water surface elev. at bankfull depth
- bankfull depth = water surface elev. req’d to completely fill channel to a point above which water would spill into floodplain
- informs watertyping (S, F, Np, Ns)
- Riparian Mgmt Zones begin @ bankfull channel edge
- RMZ inner zone width is dependent on bankfull width
- used in culvert sizing
8
Q
washington water types
A
- S: shorelines & large rivers
- F: fish bearing rivers & assoc wetlands, lakes, ponds…
- Np: non fish bearing, but perennial (year-round) flow
- Ns: non fish bearing, only seasonal/intermittent flow
9
Q
discharge measurement
A
- volumetric measurements, for very low flows
- known volume / known time = Q
- x-section / velocity-area measurements
- dilution gauging w/ dye or salt
- artificial controls like weirs
10
Q
velocity-area method
A
- continuity of mass equation
- Q = VA | (discharge = velocity * area)
- L3 / t (volume / time)
- velocity is measure .6d from surface (.4d from bottom)
- d = depth, dummy
- record x value (tape), y value (depth), velocity @ .6d
11
Q
channel substrate
A
- size is important to habitat
- land use / cover can affect
- 8 types
- sand / silt / clay
- gravel
- large gravel
- small cobble
- large cobble
- small bldrs
- large bldrs
- bedrock
12
Q
organisms used as bioindicators
A
- large mouth bass
- muskellunge
- aquatic invertebrates
- midge
- caddis fly
- stone fly
- may fly
- riffle beetle
- B-IBI: Benthic Index of Biological Integrity
- part of nutrient cycle
- differing pollution tolerances
- population flucuations (short life cycles)
13
Q
B-IBI
A
Benthic Index of Biological Integrity
- total richness
- EPT richness (mayfly, stonefly, caddis fly)
- Ephemeroptera, Plecoptera, Trichoptera
- intolerable richness
- clinger richness
- long-lived
- % tolerant
- % predator
- % dominant
14
Q
4 dimensions of hydrology
(more water moves through ecosystems thn anything else)
A
- logitudinal: upstream / downstream
- lateral: bank-to-bank, valley wall to valley wall
- vertical: water surface -> bed -> hyporheic -> groundwater
- temporal: seconds -> millenia
15
Q
logitudinal stream changes
A
upstream -> downstream…
- wider
- deeper
- slower, but w/ more volume
- also: “reach” scale = shorter than entire river length
