Post on 16-Jan-2016
Materials Transport & NSCD
Material ClassesVelocity to Transport Relationships
York NSCD RestorationPSY CCREP
Material Transport
• Organic Matter: DOM (70-90%), FPOM, CPOM, large woody debris (branches to whole trees).
• Inorganic Matter (Mineral): alluvium & bedload• Higher discharge streams can carry more and larger
particles.– Suspended load: fine suspended particles (turbidity).
– Bed load: Larger particles that bounce along bottom of stream.
– The relative amount of suspended vs. bed loads is dependent on velocity and turbulence of stream flow.
After rain, higher turbidity is not just a function of sediment run off; higher flow velocity suspends more sediments from bottom.
Total concentration of suspended particles highest near bottom.
Velocity & Material Transport Size
Deposition vs Erosion
Sediment Impacts & Contamination• Excess Sedimentation:
– Reduces hard substrate for periphyton.– Clogs gravel interstices; reduces spawning habitat for fish.– Microbial activity increase may cause oxygen depletion.– Filling and flooding.– Increases drinking water treatment costs; reduces aesthetics.
• Many chemicals, contaminants will collect within and adhere to sediments.
• Variable transport of contaminated sediments can have severe impact on biota:– Sediments collect in pools– Contaminated sediments can be retained for long periods of
time.
• Erosion is more aggressive due to unstable stream banks, flashy storm response, or sediment starved waters (e.g. below dams)
Rates of Stream-Bank Erosion
Cross Section of SBCC
486
488
490
492
494
496
498
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200
Distance (ft)
Ele
vatio
n (f
t)
Aquatic Resource Restoration Company (ARRC), unpublished data
June 2003
March 2004
October 2004
About 2-20 ft of bank lost per year.
This is 10-100 times faster than expected.
How can we stabilize our stream channels?
Continuous monitoring instrumentation (below) is placed in the stream for a
month at a time
23 September 2003
Hour (from 17:00 on 09/22/2003)
17 21 01 05 09 13 17
Dis
cha
rge
(m
3/h
)S
usp
en
de
d S
ed
ime
nt L
oa
d (
kg/h
)
0
2e+4
4e+4
6e+4
8e+4
1e+5
Rai
nfal
l (i
nch
es
pe
r h
ou
r)
0.0
0.1
0.2
0.3
0.4
DischargeSS LoadRainfall
Data collected during a storm event (above) illustrates that this is when most erosion occurs.
NSCD• Natural Stream Channel Design
• Based on science of water flow = hydrology
• New channels may be created with meanders.
• Man-made structure of rock or logs to divert flow and slow erosion.
• Considers watershed size, climate, topography and geology to determine the proper dimensions, pattern and profile for no net erosion or accretion.
“J”-hook structures along meanders.
Natural Stream Channel Design (NSCD)
Replacing the streamside (riparian) forest.
odorus Creek Restoration Efficacy Program
Studying the Effectiveness of NSCD Restoration Efforts
- Does water quality during storm events improve?
- Is there a positive biological community response?
(periphyton, macroinvertebrates, finfish)
South and East Branch
Watersheds
Downstream Continuous Monitoring Sites
Upstream Reference Sites
Completed Restoration
Planned Restoration
Water Quality& Flow
• We measure nutrients and suspended sediments in water samples during all conditions and all year!
• We also measure the stream flow to determine how much nutrient and sediments travels downstream.
Storm Event Volume to Sediment Load(3/2003 – 3/2004)
Storm Event Volume (1000 x m3)
1 10 100 1000Sed
imen
t Lo
ad (
met
ric t
ons)
0.1
1
10
100
1000
?
Periphyton = “rock slime”
Indicator of nutrient and sediment pollution.
We also monitor the macroinvertebrate community, which mostly includes stream
insects.
Fish surveys by electrofishingPeter Siwik
PA Council of Trout Unlimited, 2002
Wild spawning trout would be a hallmark of restoration success, but it will likely require fisheries management changes such “catch and release”.
Below Sewage Treatment
Plants!
Parasites
Infections
Deformations