Emily Shimada, Environmental Science, University of Idaho
Research Team B: Watershed Management in the Andean Paramo
Faculty Advisors: Dr. Alex Fremier, Department of Fish & Wildlife Resources, University of Idaho
Carlos Iñiguez A. Instituto de Ecología Universidad Técnica Particular de Loja
Introduction: Sediment in Fluvial Environments
Texture Classification
Name
Diameter (mm)
Boulders
Cobbles
Gravel
Sand
Silt
Clay
>256
64-256
2-64
0.062-2
.004-.062
<0.004
Bedload (D>1mm)
Suspended load (D<0.05mm)
Wash load (D<0.0063mm)
Introduction: Cause & Effect of Increased Fluvial Sediment
Source
Impact
Natural
Anthropogenic
Course grain/ Bedload
Fine grain/ Suspended load
 Climate
 Vegetation
 Topography
 Geology & soil
 Tectonics
 Base level
 Surface erodibility
 Time/history
 Mining
 Agriculture
 Deforestation
 Urbanization
 Dams
 Traffic/Roads/Construct
 Increased water level
 Flooding potential
 Alterations in channel
 Increased flow viscosity &
ion
 Grazing
dimensions
 Alterations in the
stream substrates
 Alterations in aquatic
organism habitat
reduced settling velocity >increase transport grain
size & bedload
 Reduced depth for sunlight
penetration ->hinders
photosynthesis
Background: Tropical Mountain Stream Ecosystems
Source
Natural
Anthropogenic
 Steep topography
Land use management
Mining activities
 Tropical Climate
 High rainfall
 Abundant vegetation
Impact
Mining
Course sedient build up->
increases channel bed
elevation (decreasing flow)
Decreased aquatic biological
activity
Research Objectives
1. What is the observed grain size distribution in:
 Streams considered “un-impacted” from human land use
activities (mining)
 Impacted stream

Above & Below sites with changes in land use
2. What is the predicted grain size distribution based on
measurable stream dimensions in:
 Streams considered “un-impacted” from human land use
activities (mining)
 Impacted stream
Above & Below sites with changes in land use
3. Is there a relationship between:
 Observed & predicted D50 in different streams and stream reaches
 Land use gradient & observed grain size distribution
 Physical stream properties & ecological functioning of the
stream?
Study Site
Methods: 1) Field Work
Site Selection
 Impacted & un-impacted
 Above & Below areas of
distinct land use differences
(mining)
 Establish sites at the Stream
Reach scale
 Length = approx. 10X
Width
 Relatively uniform slope,
dimensions, velocity
General Stream Measurements
 Velocity
 Cross-sectional Area
 Wetted Perimeter
 Turbidity
 Slope
 Depth
 Bankfull width
Sediment Property Measurements
 Pebble Count  Median Grain Size (D50)
64mm
1mm
 Wet Sieving  Median Grain Size (D50)
For sediment diameters 1mm & 2mm
Methods: 2) Analytical Work
1) Predicted grain size distribution: D 50 =
 D50 that moves at observed flow
G = gRS
 D50 that moves at bankfull flow
bf = gRS 

 cr ( s  )g
 cr  g( s  )
2) Establish relationship between
predicted &

observed D50:
 Between & within un-impacted stream reaches
 Between & within impacted stream reaches
(above and below land use site)
3) Compare grain size distribution between
impacted & un-impacted streams

6
Initiation of Motion
D tan
(shear stress)  
Additional Measurements
•Discharge Q=VA
•Turbidity
•Manning’s roughness
k(R 2/3S1/2)
n=
V
 Is there a clear correlation of grain size
distribution to land use gradient?
 Is there an ecological impact?

Relevance & Connection
Current watershed
uses & policies
Physical Impact of
current land uses
Is there an observed
ecological impact?
Bio-indicator
Framework
What is the relationship
between land use and
ecological impact?
What needs to be done?
Societal/Political
affect on watershed
use & the ecosystem
Is there an interest
and/or agenda for
watershed protection?
What can be done at the local & international
level order to accommodate cultural values
and stakeholders’ interests, while promoting
sustainable land use practices and policies?
Watershed use &
policy jurisdiction
(stakeholders)
Cultural & political
Perceptions of watershed
use & resulting impacts
Thanks & References
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Images: http://www.amazonrainforestnews.com/2011_04_01_archive.html
http://www.nativerevegetation.org/learn/manual/ch_5.aspx
http://www.amazonconservation.org/news/newsletter/0812/index.html
http://www.uwsp.edu/geo/faculty/lemke/geomorphology/lectures/03_stream_sediment.html