altered hydrology & vegetation: effects on the transport and breakdown of organic matter in...
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Altered Hydrology & Vegetation: Effects on the Transport and Breakdown of Organic Matter in Urban Streams
Kenneth T. Belt1, Christopher Swan2, Richard Pouyat1, Sujay Kaushal3, Peter Groffman4, Istvan Turcsanyi5, William Stack6, and Gary Fisher7
1 USDA Forest Service, 2 UMBC Dept. of Geography and Environmental Systems3 UMCES Appalachian Lab, 4 Institute of Ecosystem Studies, 5, UMBC Center for Urban Environmental Research & Education, 6 Baltimore City
DPW, 7 USGS
BES Annual Meeting, Baltimore, UMBC, October 19, 2006
UMBCUMBC
Outline
•Urban Drainage Networks•Leaf Breakdown•DOC Export (preliminary)•POM Export (preliminary)•Ongoing Work
Support…
•Phyl (my wife)…arthritic bag making sessions, field work…putting up with me.
•Rich Pouyat (USFS)…Guidance, encouragement, bag making…field work (the infamous blind rainstorm drive)
•Chris Swan (UMBC GES)…guidance, encouragement, nutrient analysis, bug picking support
•Sujay Kaushal (UMCES)…guidance, encouragement, DOC analyses
•Peter Groffman/Dan Dillon, Gio et al. (IES)…sampling support, nutrient data; loan of an “ISCO”
•Claire Welty (CUERE)…facilities, guidance; loan of 2 “ISCOs”
•Istvan Turcsanyi (CUERE)…guidance and endless filtering and weighing
•UMBC GES interns: Bill Greenwood, Yaakov Birnbaum, Heather Modic
•All those technicians & colleagues…..
Motivation
•Leaves (and breakdown products & leachate) in streams are an important energy (food) source
•They also are habitat
•They are important in a variety of BGC reactions and pathways
•They also likely carry significant, not heretofore considered, elemental/pollutant loads
•Urban Drainage Networks
Buried Urban Streams
Increased Effective Drainage Density in Urban Streams
Curb & GutterNetwork
“Upland Riparian” Streams…
….Deliver Particulate & Dissolved Loads to Streams
Urban Landscapes & Organic Matter Transport
The Gutter Subsidy
Estimate of Baltimore Gutter Leaf Loads (whole Catchment Area Basis; Error Bars Show Range of Estimate)
0
500
1,000
1,500
2,000
2,500
3,000
3,500
4,000
4,500
5,000
Pond
Baism
an
Glyndon
Delig
ht
Red R
un
Horseh
ead
Villa
Nova
Scotts
Lev
el
Dead R
un
Owings
Mill
s
Catchment
Cat
chm
ent
An
nu
al C
urb
Lea
f L
oad
(Kg
Dry
Mas
s/h
a)
0
10
20
30
40
50
60
70
80
90
100
Ro
ad D
ensi
ty (
km/s
q k
m)
CatchmentRoad Density
Civil Infrastructure and Organic Matter
POM
Pollutants
OutputsTo Stream
OutputsTo Stream
Forest Stand Urban Landscape
Leaf Breakdown
How quickly do leaves breakdown in the stream benthic environment?
Mass Loss from Leaf Bags
Mass Remaining Baismans Run (Forested Catchment)
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0 20 40 60 80 100
Days
Ma
ss
Re
ma
inin
g
GS F
GU F
LS F
LU F
RD F
RP F
RS F
RU F
Collection Dates:1st Jan 3 2nd Jan 203rd Feb 34th Mar 35th Mar 30
Bags installed on Dec 24 2004
Breakdown Rates: Mass Loss Coefficients
Exponential decay model:
Wt W0-1 = e-kt
•W0 = the initial leaf mass (g)
•Wt is the mass (g) remaining on day t
•k is the rate of breakdown (day-1)
Leaf Breakdown: Basic Questions…Streams, Sources &
Landscape Position
1. Do leaves breakdown faster in suburban than in forested streams?
2. Do leaves from upland portions of the urban landscape breakdown faster than riparian leaves?
3. Do leaves from gutter sources break down faster than leaves from higher points in the landscape and riparian leaves?
4. Do riparian leaves from different locations along the urban-rural gradient differ in their breakdown rates?
Stream Study Sites
Baismans Run(Forested)
Gwynns FallsAt Gwynnbrook
(Suburban)
10 kilometers
Leaf Litter Breakdown Study Streams
Baltimore City
Gwynns Falls at Gwynnbrook(Suburban)
Baismans Run(Forested)
Baismans Run
Gwynns Falls at Gwynnbrook
Study Stream Catchments
Riparian Source Sites(Sycamore)
Distal Riparian (rural)
Suburban Riparian
Urban,Riparian
ProximalRiparian(rural)
Suburban Landscape
UrbanLandscape
Urban,Gutter
Suburban, Gutter
Lawn (“Landscape”) & Gutter Source Sites(Planetree)
Sycamore Leaf Mass Loss Rates: Different Spatial Sources
Leaf Breakdown Rates in Forested and Suburban Streams
-0.009
-0.008
-0.007
-0.006
-0.005
-0.004
-0.003
-0.002
Pla
tan
acea
e*
Su
bu
rban
Gu
tter
Urb
anG
utt
er
Su
bu
rban
Lan
dsc
ape
Urb
anL
and
scap
e
Rip
aria
nR
ura
l(D
)
Rip
aria
nR
ura
l(P
)
Rip
aria
nS
ub
urb
an
Rip
aria
nU
rban
Mas
s L
oss
Co
eff.
(m
ass
loss
per
day
)
Fast
(>0.010 day-1)
Slow
(< 0.005 day-1)
* Webster (1986) (14 estimates)
Forested Stream(Baismans Run)
Suburban StreamG.Falls Gwynnbrook)
Gutter Landscape RiparianSuburb Urban Suburb Urban Rural Rural Suburb Urban (Distal) (Prox)
*
``
Study Streams: Light Green- Forested, Dark Green- Suburban
Suburban Stream
Forested Stream
Leaf Mass Loss Rates
(Sycamore)(Planetree)Litter Sources
Urban Streams… Faster
Mass Loss: Urban vs. Suburban Streams
Sycamore Leaf Mass Loss Rates: Different Spatial Sources
Leaf Breakdown Rates in Forested and Suburban Streams
-0.009
-0.008
-0.007
-0.006
-0.005
-0.004
-0.003
-0.002
Pla
tan
acea
e*
Su
bu
rban
Gu
tter
Urb
anG
utt
er
Su
bu
rban
Lan
dsc
ape
Urb
anL
and
scap
e
Rip
aria
nR
ura
l(D
)
Rip
aria
nR
ura
l(P
)
Rip
aria
nS
ub
urb
an
Rip
aria
nU
rban
Mas
s L
oss
Co
eff.
(m
ass
loss
per
day
)
Fast
(>0.010 day-1)
Slow
(< 0.005 day-1)
* Webster (1986) (14 estimates)
Forested Stream(Baismans Run)
Suburban StreamG.Falls Gwynnbrook)
Gutter Landscape RiparianSuburb Urban Suburb Urban Rural Rural Suburb Urban (Distal) (Prox)
*
``
Leaf Mass Loss Rates
Riparian sources Slower
Mass Loss Rates: Upland vs. Riparian
Sycamore Leaf Mass Loss Rates: Different Spatial Sources
Leaf Breakdown Rates in Forested and Suburban Streams
-0.009
-0.008
-0.007
-0.006
-0.005
-0.004
-0.003
-0.002
Pla
tan
acea
e*
Su
bu
rban
Gu
tter
Urb
anG
utt
er
Su
bu
rban
Lan
dsc
ape
Urb
anL
and
scap
e
Rip
aria
nR
ura
l(D
)
Rip
aria
nR
ura
l(P
)
Rip
aria
nS
ub
urb
an
Rip
aria
nU
rban
Mas
s L
oss
Co
eff.
(m
ass
loss
per
day
)
Fast
(>0.010 day-1)
Slow
(< 0.005 day-1)
* Webster (1986) (14 estimates)
Forested Stream(Baismans Run)
Suburban StreamG.Falls Gwynnbrook)
Gutter Landscape RiparianSuburb Urban Suburb Urban Rural Rural Suburb Urban (Distal) (Prox)
*
``
Leaf Mass Loss Rates
“Gutter”… about the same as “Landscape”
Litter Sources: Gutter vs. Landscape
Sycamore Leaf Mass Loss Rates: Different Spatial Sources
Leaf Breakdown Rates in Forested and Suburban Streams
-0.009
-0.008
-0.007
-0.006
-0.005
-0.004
-0.003
-0.002
Pla
tan
acea
e*
Su
bu
rban
Gu
tter
Urb
anG
utt
er
Su
bu
rban
Lan
dsc
ape
Urb
anL
and
scap
e
Rip
aria
nR
ura
l(D
)
Rip
aria
nR
ura
l(P
)
Rip
aria
nS
ub
urb
an
Rip
aria
nU
rban
Mas
s L
oss
Co
eff.
(m
ass
loss
per
day
)
Fast
(>0.010 day-1)
Slow
(< 0.005 day-1)
* Webster (1986) (14 estimates)
Forested Stream(Baismans Run)
Suburban StreamG.Falls Gwynnbrook)
Gutter Landscape RiparianSuburb Urban Suburb Urban Rural Rural Suburb Urban (Distal) (Prox)
*
``
Leaf Mass Loss Rates
Urban… Much faster than Suburban
No Effect for Riparian Leaves?
The Riparian Urban-Rural Gradient
Sycamore Leaf Mass Loss Rates: The Urban-Rural Gradient
Leaf Breakdown Rates in Forested & Suburban Streams-0.009
-0.008
-0.007
-0.006
-0.005
-0.004
-0.003
-0.002
-0.001
0.000
Pla
tan
acea
*
. R
ura
l-
.R
ipar
ian
(D
)
. R
ura
l-
.R
ipar
ian
(P
)
. Su
bu
rban
- .
. G
utt
er
.
. Su
bu
rban
- .
. Lan
dsc
ape-
. Su
bu
rban
- .
. R
ipar
ian
.
. U
rban
-
..
Gu
tter
.
. U
rban
-
.. L
and
scap
e-
. U
rban
-
..
Rip
aria
n
.
Lo
ss C
oef
fici
ent
(mas
s lo
ss p
er d
ay) Fast
(> 0.010 day-1)
Slow
(< 0.005 day-1)
Forested Stream(Baismans Run)
Suburban StreamG.Falls Gwynnbrook)
* Webster (1986) (14 estimates)
Rural Suburban Urban Riparian Gutter LScape Riparian Gutter LScape Riparian (Distal) (Prox)
Leaf Mass Loss Rates
DOC Export
DOC Export in Urban Streams
1. How do urban DOC concentrations and export rates compare to “natural” systems ?
2. How much does DOC transport vary temporally (seasonal); how important is hydrology (storms)?
3. Is drainage density (and its attendant features) important?
Preliminary DOC & Flow Data
•8 of 13 sites•15 to 20 samples at each site•July to November 2005•Grab sampling…every few weeks
•Mostly dry weather•Some with recent storm runoff activity (within days)
Gwynns Falls at Gwynnbrook Avg Daily Flow & DOC Concentration
1
10
100
1000
7/17/2005 8/6/2005 8/26/2005 9/15/2005 10/5/2005 10/25/2005 11/14/2005
Av
g D
ail
y Q
(c
fs)
0
1
2
3
4
5
6
7
8
DO
C c
on
c (
mg
/l)
Q cfs
GFGB (Suburb)
DOC Concentration vs. Flow Ratepreliminary data
y = 1.6357Ln(x) + 0.7348
R2 = 0.624
y = 2.6863x0.2266
R2 = 0.1683
0.1
1
10
100
0.1 1 10 100 1000
Avg Daily Flow (cfs)
DO
C (
mg
/l)
DRKR
GFGB
Log. (GFGB)
Log. (DRKR)
Average Daily Flow Rate vs. Impervious Cover(8 catchments, July - Nov 2005
0.0
0.5
1.0
1.5
2.0
2.5
-5 5 15 25 35 45 55
Catchment Impervious Surface Cover (%)
Avg
Dai
ly F
low
(m
m/d
)
Forested & Agric Sites
More Urbanization
More ISC…More Runoff
Average DOC Concentration vs. Impervious CoverJuly - Nov 2005, 8 catchments, N = 15 to 20 (each)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
-5 5 15 25 35 45 55
Catchment Impervious Surface Cover (%)
Avg
DO
C C
on
c (m
g/l)
Forested & Agric Sites
More Urbanization
More ISC…Higher DOC Conc
Average DOC Areal Loading Rate vs. Impervious CoverJuly - Nov 2005, 8 catchments, N = 15 to 20 (each)
0
20
40
60
80
100
120
140
-5 5 15 25 35 45 55
Catchment Impervious Surface Cover (%)
DO
C L
oad
ing
(g
/ha/
day
)
Forested & Agric Sites
More Urbanization
More ISC…Higher Catchment DOC Exports
DOC Areal Load vs Areal Flow Rate(8 catchments, 15-20 samples each, July-Nov 2005)
0.1
1
10
100
1000
0.01 0.10 1.00 10.00 100.00Areal Avg Daily Flow (mm/d)
DO
C A
real
Lo
ad R
ate
(g/d
/ha)
PBDOC_ALd
MDDOC_ALd
BRDOC_ALd
GBDOC_ALd
VNDOC_ALd
GLDOC_ALd
CPDOC_ALd
DRDOC_ALd
Power (DRDOC_ALd)
Forested &Agricultural Sites(Green Triangles)
Dead Run Trendline(Power Function)
Urban catchments…High DOC exports at higher flows
Urban catchments produce large DOC loads…including at elevated flows
And these loads may be related to to impervious area cover & infrastructure…?
POM Export
POM Export in Urban Streams
1. How do urban POM concentrations and export rates compare to “natural” systems ?
2. How much does POM transport vary temporally (seasonal); how important is hydrology (storms)?
3. Is drainage density (and its attendant features) important?
AFDM & TSS at 3 SitesBaismans R, GFalls at Gwynnbrook, Dead R; Apr to Sep 2006
Gwynns Falls at Gwynnbrook AFDM & TSS(GFGB) Spring-Summer 2006
0.1
1.0
10.0
100.0
24-Mar 13-Apr 3-May 23-May 12-Jun 2-Jul 22-Jul 11-Aug 31-Aug 20-Sep
AF
DM
& T
SS
(m
g/l
)
AFDM50 (mg/l)
TSS105 (mg/l)
Avg: 39% Organic Matter
Suburban
Baismans Run AFDM & TSS(BARN) Spring-Summer 2006
0.1
1.0
10.0
100.0
24-Mar 13-Apr 3-May 23-May 12-Jun 2-Jul 22-Jul 11-Aug 31-Aug 20-Sep
AF
DM
& T
SS
(m
g/l
)
AFDM50 (mg/l)
TSS105 (mg/l)
Forested
Avg: 31% Organic Matter
Dead Run AFDM & TSS (DRKR) Spring-Summer 2006
0.1
1.0
10.0
100.0
24-Mar 13-Apr 3-May 23-May 12-Jun 2-Jul 22-Jul 11-Aug 31-Aug 20-Sep
AF
DM
& T
SS
(m
g/l
)
AFDM50 (mg/l)
TSS105 (mg/l)
Avg: 52 % Organic Matter
Urban
% Organic Matter
Forested: 31 % Suburban: 39 %Urban: 52%
% Organic MatterApr-May Jun-Sep
Forested: 40 % 29 % Suburban: 50 % 37 %Urban: 42 % 54%
TSSAFDM
Forested
Suburban
Urban
AFDM & TSS11 Sites; Spg-Sum 2006 (+/- Std Dev)
0.1
1.0
10.0
100.0
1000.0
POBR BARN MCDN GFGB GFGL MNBK GFVN GFCP DRKR MAWI GRGF
AF
DM
(m
g/l)
Avg AFDM
Avg TSS
Increasing Urbanization
Reference Sites
Highly Urban Sites
AFDM & TSS at 11 SitesSpg-Sum 2006
Ongoing/Future Work
Organic Matter…the Urban Dilemma
•Urban streams: faster particle breakdown …greater export rates from the benthic ecosystem…carbon poor benthos
But….
•Higher urban imports (gutter subsidy)?
•Smaller particles?
•Leached loads (DOC)?
Organic Matter in Streams:Types of OM
DOC- dissolved OM FPOM- fine particulate OMCPOM- coarse particulate OM
Organic Matter in Streams:Basic Transport Pathways
DOC
CPOM
FPOM
Groundwater
Surface &
Shallow
Groundwater
Leaching
Surface
WatersDOC
Riparian & Upland Litterfall
•13 gauged BES catchments…an urban-rural gradient
•Storm and dry weather sampling
•Intensive sampling with auto samplers at 3 catchments
•Particulate and dissolved organic matter
•Urban hydrology approach
•Sediment exports (% organic matter)
Basic Approach
Bridge
Dry Weather Flow
StormFlow
Discrete Storm FPOM Samples
Discrete Storm CPOM Samples
24 hr CPOM Sampler (Dry
Weather Flow)Whole Storm
CPOM Sampler
Peak Storm Flow CPOM Sampler
(stationary)
Intensive Site Sampling Conceptual Scheme
Automated Sampler
FPOM Grab (Dry Weather Flow)
USGS Stage
Recorder
Gwynns FallsMain Channel Stream Sites
Small Headwater Stream Sites
Subcatchment Stream Sites
BaismansRun
GwynnsFalls
BES Stream Sites: Routine & Intensive
GFGB
GFVN
GFCP
BARNPOBR
DRKR
3 IntensiveMonitoringSites
13 Routine Sampling Sites:
Gwynns FallsMain Channel Stream Sites
Small Headwater Stream Sites
Subcatchment Stream Sites
BaismansRun
GwynnsFalls
BES Stream Sites: Auto Storm Composites
GFGB
GFVN
RGHT
BALT &LANV
7 Auto SamplerStormCompositeSamplers
(including the 3 OM intensive Sites)
13 Routine Sampling Sites:
A Multidisciplinary, Cooperative Effort…
US Forest ServiceUMBC Geography & Environmental SystemsUMCES Appalachian LabCenter for Urban Environmental Research and EducationBaltimore Ecosystem Study/Institute of Ecosystem StudiesCity of Baltimore DPWUS Geological Survey
…and more partners to come