In–stream nitrogen In–stream nitrogen processing in urban processing in urban

degraded and restored degraded and restored streams in streams in

Baltimore, MDBaltimore, MDCarolyn 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-vegetation Rip 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 plateauAllow the concentrations to reach plateau 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

10m21m51m74m116m

MNBK 7-17-06

y = -0.0013x + 1.5355R2 = 0.2183

1.251.3

1.351.4

1.451.5

1.551.6

0 20 40 60 80 100 120 140

Distance from injetion

aver

age

solu

te:

trace

r

Minebank RunMinebank Run 22ndnd order stream order stream Upstream reach Upstream reach

restored restored in 1998 and 1999in 1998 and 1999

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 ofHeadwater tributary of the larger 3the larger 3rdrd order order

Dead Run Dead Run Gwynn Falls WatershedGwynn Falls Watershed Little riparian bufferLittle riparian buffer Visible channel incisionVisible channel incision

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 D E

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 Peter Sujay Kaushal, Paul Mayer, and Peter

GroffmanGroffman 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????