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In–stream nitrogen In–stream nitrogen processing in urban processing in urban
degraded and restored degraded and restored streams in streams in
Baltimore, MDBaltimore, MD
Carolyn A. Klocker (UMCES)Carolyn A. Klocker (UMCES)Sujay Kaushal (UMCES), Peter Sujay Kaushal (UMCES), Peter Groffman (IES), and Paul Mayer Groffman (IES), and Paul Mayer
(EPA)(EPA)BES Annual MeetingBES Annual Meeting
10/19/0610/19/06
Nitrogen retention and Nitrogen retention and removal removal
in streamsin streams Nitrogen being retained and removed Nitrogen being retained and removed
in both small headwater streams in both small headwater streams (Peterson et al 2001) and larger rivers (Peterson et al 2001) and larger rivers ≥ 5≥ 5thth order (Seitzinger et al 2002) order (Seitzinger et al 2002)
Nitrogen retention or removal Nitrogen retention or removal
= Inputs - Outputs = Inputs - Outputs Includes biotic uptake, retention in Includes biotic uptake, retention in
sediments and denitrificationsediments and denitrification
Sediment inputs
Nutrient inputs
Bank Incision
Removal of riparian zone
Stream Degradation
Increased Nitrogen Concentrations
Lateral movement of stream channel
Stream Restoration
Bank re-shaping
Cross Vane
Re-vegetationRip Rap
Channel manipulation
Substrate manipulation
Erosion control
ObjectiveObjective
To determine the nitrogen retention To determine the nitrogen retention ability of 4 urban streams, 2 ability of 4 urban streams, 2 restored and 2 degraded, using the restored and 2 degraded, using the metrics of nutrient spiraling theory. metrics of nutrient spiraling theory. uptake length, uptake rate, and uptake uptake length, uptake rate, and uptake
velocity velocity To compare these values to known To compare these values to known
literature values recently reportedliterature values recently reported
Nutrient spiraling theoryNutrient spiraling theory
http://limnology.wisc.edu/courses/zoo548/Nutrient%20spiraling_handout.pdf
NO3
Retention ParametersRetention Parameters Uptake length Uptake length
SSww = = Q CQ C
U wU w
Uptake rateUptake rate UU = v = vff C C
Uptake velocityUptake velocity vvff == Q Q
SSww w w
Q = dischargeC = concentration of nutrientw = stream width
(Stream Solute Workshop 1990)
Nutrient additionsNutrient additions GoalsGoals
To add a solution increasing the nutrient To add a solution increasing the nutrient in question (NOin question (NO33-) and a conservative -) and a conservative tracer (Br-) tracer (Br-)
Allow the concentrations to reach Allow the concentrations to reach plateauplateau
Uptake length = the inverse slope of the Uptake length = the inverse slope of the regression of the ln (corrected regression of the ln (corrected concentration) of NOconcentration) of NO33- verses distance - verses distance downstreamdownstream
MNBK 7-17-06 NT INJ [Br] (mg/L)
0
0.1
0.2
0.3
0.4
0.5
0.6
700 900 1100 1300 1500 1700
Time
[Br]
mg
/L
10m21m
51m74m116m
MNBK 7-17-06
y = -0.0013x + 1.5355
R2 = 0.2183
1.25
1.3
1.35
1.4
1.45
1.5
1.55
1.6
0 20 40 60 80 100 120 140
Distance from injetion
aver
age
solu
te:
trac
er
Minebank RunMinebank Run 22ndnd order stream order stream Upstream reach restored Upstream reach restored
in 1998 and in 1998 and 19991999
Goal of the restoration Goal of the restoration was to improve the was to improve the geomorphic stability of geomorphic stability of the stream bed and the stream bed and reduce incisionreduce incision
Restoration SitesRestoration Sites
Spring BranchSpring Branch 11stst order stream order stream Loch Raven WatershedLoch Raven Watershed Drains directly into the Drains directly into the
Loch Loch
Raven Reservoir Raven Reservoir Restoration 1994 - 1997Restoration 1994 - 1997 Goal of the restoration was Goal of the restoration was
to manage the flow of the to manage the flow of the stream to control for stream to control for erosion and floodserosion and floods
GlyndonGlyndon 11stst order stream order stream BES LTER streamBES LTER stream Gwynn Falls WatershedGwynn Falls Watershed Visible channel incisionVisible channel incision Little riparian bufferLittle riparian buffer Analytical problemsAnalytical problems
Interference with BromideInterference with Bromide
Degraded SitesDegraded Sites
DR 5DR 5 Headwater tributary Headwater tributary
ofof
the larger 3the larger 3rdrd order order
Dead Run Dead Run Gwynn Falls Gwynn Falls
WatershedWatershed Little riparian bufferLittle riparian buffer Visible channel Visible channel
incisionincision
MethodsMethods NONO33- and Br- added for approximately - and Br- added for approximately
8-10 hrs at 45 mL/min8-10 hrs at 45 mL/min 5 sampling locations5 sampling locations Collected approx. every 30 minutesCollected approx. every 30 minutes Samples were filtered, frozen and Samples were filtered, frozen and
analyzed using a dx 500 Ion analyzed using a dx 500 Ion ChromatographChromatographI A B
C DE
NO3- Q Sw U vf
Site Type (mg/L) (L/s) (m) (μg N m-2 s-1) (mm/s)
GLYN Degraded 1.75 0.75
DR5 Degraded 0.55 0.5 250 1.55 2.86 X 10-3
MNBK Restored 1.08 0.5 770 1.01 9.29 X 10-4
SPBR Restored 2.78 1.75 238 7.06 2.53 X 10-3
ResultsResults
NO3- Q Sw U vf
Site Type (mg/L) (L/s) (m) (μg N m-2 s-1) (mm/s)
GLYN Degraded 1.75 0.75
DR5 Degraded 0.55 0.5 250 1.55 2.86 X 10-3
MNBK Restored 1.08 0.5 770 1.01 9.29 X 10-4
SPBR Restored 2.78 1.75 238 7.06 2.53 X 10-3
ResultsResults
NO3- Q Sw U vf
Site Type (μg/L) (L/s) (m) (μg N m-2 s-1) (mm/s)
SPBR Restored 2780 1.75 238 7.06 2.53 x 10-3
DR5 Degraded 550 0.5 250 1.55 2.86 x 10-3
MNBK Restored 1080 0.5 770 1.01 9.29 x 10-4
GLYN Degraded 1750 0.75
AFR Unaltered 5 15.4 67 0.38 0.077
SYC Unaltered 21 55 90 4.3 0.200
RRD Earthen 18 27.4 294 0.38 0.021
IBW Earthen 100 49 555 2.2 0.022
GDR Earthen 1220 113 526 87 0.072
PRD Concrete 5241 187 833 294 0.056
HLC Concrete 6111 306 1245 734 0.120
DMB-D Agriculture 23 10304 4.4
DMB-P Agriculture 22 27534 2.08
Erpe-D Agriculture 164 11529 4.4
Erpe-P Agriculture 511 6977 92.2
(Grimm 2005, Gucker and Pusch 2006)
800 to 16400
Implications and Future Implications and Future DirectionsDirections
As restoration projects age the may be As restoration projects age the may be able to retain nitrogen more efficientlyable to retain nitrogen more efficiently
Need to look at more than just the state Need to look at more than just the state of the streamof the stream Watershed characteristicsWatershed characteristics DOCDOC Periphyton densities and chlorophyll aPeriphyton densities and chlorophyll a Geomorphic structuresGeomorphic structures
Data to be analyzedData to be analyzed
Isotope additionsIsotope additions Maintain ambient nutrient Maintain ambient nutrient
concentrationsconcentrations In situ denitrification ratesIn situ denitrification rates 2 completed at Minebank Run in August 2 completed at Minebank Run in August
20062006 Denitrification Enzyme Assays (DEA)Denitrification Enzyme Assays (DEA)
Conducted at all 4 sites in late June to Conducted at all 4 sites in late June to early July of 2006early July of 2006
AcknowledgementsAcknowledgements
Sujay Kaushal, Paul Mayer, and Sujay Kaushal, Paul Mayer, and Peter GroffmanPeter Groffman
Pete Bogush and Tammy NewcomerPete Bogush and Tammy Newcomer Dan Dillon, Ho-Jin KimDan Dillon, Ho-Jin Kim
Paul Lilly and Melanie Paul Lilly and Melanie
HarrisonHarrison Katie Kline and Katie Kline and
Keith EshlemanKeith Eshleman EPA and ALEPA and AL
Restored Urban Stream: Developed Stage
Increased organic matter
Healthy riparian zones
Decreased Nitrogen Concentrations????