leaf collection as a means to reduce phosphorus from urban … · 2013. 4. 24. · sugar maple 260...
TRANSCRIPT
Leaf Collection as a Means to Reduce Phosphorus from Urban Areas
Problem: Urban sources of nutrients
• Nutrients in runoff “fertilize” receiving water bodies – Eutrophication – Odor – Loss of use
• Organic detritus and particulate matter major sources of nutrients in urban setting
• Control of Total P required through TMDL
• Little research to quantify the effect of leaf collection on water quality
Photo by Kyle McDaniel, Wis. State Journal
Photo by USGS
Sources of Phosphorus in Urban Environment
Waschbusch et al., 1999
Background
• Rock River TMDL - Total Phosphorus
• Leaf collection identified by Yahara CLEAN as reasonable measure to reduce Total P delivered to Madison lakes
• Model simulations (WinSLAMM) estimate 23% of annual P load occurs in fall
– Probably biased low
• What % reduction (credit) can Madison or other municipalities in Rock River basin expect by collecting leaves in the fall?
– Could potentially help meet phosphorus goals simply by maintaining an existing program
– Will expanding beyond fall improve reduction percentages?
Type of Monitoring
Type of Program for Test Basins (Control sites will always have no collection)
Year 1 Year 2 Year 3 Year 4 Year 5
Water Quality No collection Existing Escalated TBD Report
Gross Solids No collection Existing Escalated TBD Report
Street Loads No collection Existing Escalated TBD Report
Approach: Paired-basin study design
Control no collection
Test existing/escalated practices
TBD = to be determined
Study Location
Measurement of Phosphorus in Water and Leaves
Photos by USGS
Processing Facility for Collected Leaves at Madison Metropolitan Sewerage District
Photos by USGS
2012 Project Timeline
September 13th
October 9th
October 31st
November 13th
- Received verification of funding
- First water-quality sample collected (after 17 consecutive dry days)
- All monitoring stations and trash nets installed
- Project suspended for winter; all streets cleared of leaves
Sample ID Date Dissolved Total P Total P TSS TOC DOC
Y-1 10/09/2012 4.78 5.08 74 300 300
Y-2A 10/13/2012 2.36 2.86 66 140 130
Y-2B 10/13/2012 1.370 1.55 24 86 82
Y-2C 10/13/2012 0.981 1.06 30 63 62
Y-2D 10/13/2012 0.163 0.30 69 7.8 6.3
Y-2E 10/13/2012 0.328 0.39 28 22 20
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
Y-2A Y-2B Y-2C Y-2D Y-2E
Tota
l Ph
osp
ho
rus,
in m
g/L
0
10
20
30
40
50
60
70
80
Y-2A Y-2B Y-2C Y-2D Y-2E
TSS,
in m
g/L
Sample Results
Phosphorus Speciation
>70% of dissolved P is orthophosphate
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Y-1 Y-2A Y-2B Y-2C Y-2D Y-2E
Perc
enta
ge o
f P
ho
sph
oru
s in
th
e D
isso
lved
or
Part
icu
late
Ph
ase
Particulate P
Dissolved P
Canopy-Low Canopy-Med Canopy-High 0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
Dis
solv
ed P
ho
shp
rus
Co
nce
ntr
atio
n, i
n m
g/L
Y-1
Y-2
Canopy-Low Canopy-Med Canopy-High 0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
Tota
l Ph
osp
ho
rus
Co
nce
ntr
atio
n, i
n m
g/L
Event Mean Concentration
Event Mean Concentration
Comparison to Previous Data - Concentration
Data from Waschbusch and others, 1999
Y-2
Y-1
Comparison to Previous Data - Concentration
Site-KR Site-KN Site-P 0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
Tota
l Ph
osp
ho
rus,
in m
g/L
Y-1
Y-2
KN.OrthoP KR.OrthoP Pipe.OrthoP 0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
Ort
ho
ph
osp
ho
rus,
in m
g/L
Y-1
Y-2
Data from Selbig and Bannerman, 2007
Site-KR Site-KN Site-P 0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
Tota
l P L
oad
, in
lbs.
Y-1
Y-2
KN.OrthoP KR.OrthoP Pipe.OrthoP 0
0.5
1
1.5
2
2.5
3
3.5
Ort
ho
ph
osp
ho
rus
Load
, in
lbs.
Y-1
Y-2
Comparison to Previous Data - Load
Data from Selbig and Bannerman, 2007
Comparison to Previous Data - Yield
Site-KR Site-KN Site-P 0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
Tota
l P Y
ield
, lb
s./a
cre
Y-1
Y-2
Data from Selbig and Bannerman, 2007
Sample Total P Water (lbs.)
Total P Leaves (lbs.)
Y-1 0.43 0.002
Y-2 2.17 0.014
Phosphorus in Leaves Tree Species
Leaves Leachable Phosphorus
µg/gm
Sugar Maple 260
Silver Maple 233
Green Ash 188
Honey Locust 176
White Ash 162
American Elm 159
Basswood 96
Chinese Elm 89
Little Leaf
Linden
87
Pin Oak 82
Norway Maple 80
Hessian Ash 66
Weeping
Willow
38
All Leaves 148
Seeds
Green Ash 78
Sugar Maple 41
Little Leaf
Linden
39
All Seeds 48
Data from Dorney, 1986
Summary
• Early results indicate very high P concentration and yield when leaves are not collected
• Majority of P is in the dissolved phase as orthophosphate
• Leaves transported off street may not be a significant part of P load based on published values
• Leaf collection/sweeper timing (frequency) could be crucial
• Measurement of P in Spring will help characterize seasonality