michael kemp maureen brooks jeremy testa box model analysis of the corsica river 2005–2006
TRANSCRIPT
Michael Kemp Maureen Brooks Jeremy Testa
Box Model Analysis of theCorsica River2005–2006
Box Model Boundary
Sycamore Point
Possum Point
Cedar Point
The Sill
CONMON
WWTP
Box 2
Corsica River Study Site
SONE
Box 3
Box 1
Single Box ModelPrecipitation – EvaporationRunoff,
River Flow
Waste-water
Outflow
Non -AdvectiveExchange
Chester RiverCorsica River
Qww
Qr
Qp-e
Qout
ECh-Co
Water Balance: Qout = Qr + Qp-e + Qww
Salt Balance: ECh-Co = (Qout) [SCo/(SCh-SCo)]
SChesterSCorsica
Caveates in this Analysis
Analyses generated thus far are very preliminary because they are based on incomplete data.
Stream flow & nutrient loading rates estimated using tentative data & untested assumptions on weighting & extrapolation.
Point-source and atmospheric inputs taken from different years, with “interpolation” to common year.
Weighted extrapolation from USGS gauged site.
Many observed patterns are very clear and may be robust (i.e., strong signal showing through noise of questionable data.
Single Box Model: Water-Transport
1
116
1.2
118.2
1040
Chester RiverCorsica River
(103 m3 d-1)
2005
70.2
1
68
1.2 275
2006
2005: April to October Transports2006: May to October Transports
Single Box Model: DIN Transport
20
364
21
25
23
Chester RiverCorsica River
(kg d-1)
402
= 265 mol m-2 h-1
(net uptake)
6
2005
20
211
21 77
323
= 214
2006
Single Box Model: DIP Transport
0
556
506
756
438
Chester RiverCorsica River
133
= 0.11 mol m-2 h-1
(net release)
0
323
506
1080
3772
= 3.28
4023
(kg d-1)
Single Box Model: Biogeochemical Rates
Net DIN Production (mol N m-2 h-1):
Net DIP Production (mol P m-2 h-1):
Denitrification (mol m-2 h-1):
Net Ecosystem Prod. (g C m-2 y-1):
Water Residence Time (FFW, d):
2005 2006
-265 -214
0.11 3.28
267 266
-1 -37
85 145
Chester River
21
276
5
37
55Box 1 Box 2
24
772
1588
(kg d-1)
209 943
= 601 mol m-2 h-1
(net uptake)
= 683 mol m-2 h-1
(net uptake)
21
161
5
4
3
6
105
1551
185 167
= 530 = 144
DIN Transport in 2-Box Model
Chester River
1.4
1.2
0
1.1
1.8Box 1 Box 2
2.3
92.4
00.4
0.3 91.4
= 4.14 mol m-2 h-1
(net uptake, release)
= 36.9 mol m-2 h-1
(net release)
1.4
0.7
0
2.9
5.1
2.5
11.8
00.2
5.9 6.1
= 7.7 = 2.5
(kg d-1)
DIP Transport in 2-Box Model
DIN Transport in 3-Box Model
Corsica River
14.5
92.5
2.1
3.9
4.6
Box 1 Box 23.6
12.4
15.722.8
OutputBox 3
Precip Non-point
Non-Advective
Non-point
Point
3.8
(-100.6) (-43.9) (-28.1)
9.1
5.2
17.3
Chester River
Net Flux
(kg d-1)
Monthly Net Fluxes of DIN & DIP: 1-Box
-400.00
-350.00
-300.00
-250.00
-200.00
-150.00
-100.00
-50.00
0.00
May June July August September October
DIN
NO23
NH4
-2.00
-1.00
0.00
1.00
2.00
3.00
4.00
May June July August September October
DIP
DIP Flux
DIN Flux
May Jun Jul Aug Sep Oct
DIN Flux
-1000.00
-800.00
-600.00
-400.00
-200.00
0.00
200.00
400.00
May June July August September October
um
ol
m-2 h
-1
Box 1
Box 2
DIP Flux
-4.00
-2.00
0.00
2.00
4.00
6.00
8.00
10.00
May June July August September October
um
ol m
-2 h
-1
Box 1
Box 2
DIN Flux
DIP Flux
May Jun AugJul Sep Oct
Monthly Net Fluxes of DIN & DIP: 2-Box
Box 1Box 2
Box 1Box 2
DIN-700
-600
-500
-400
-300
-200
-100
0
Box 1 Box 2 Box 3
um
ol
m-2 d
-1
DIP
0
2
4
6
8
10
12
Box 1 Box 2 Box 3
um
ol
m-2 d
-1
Mean Net Fluxes of DIN & DIP: 3-Box
Box 1 Box 2 Box 3
Box 3Box 2Box 1
DIN Flux
DIP Flux
Key preliminary conclusions
1) Consistent high rates of net DIN uptake within Corsica (retention or transformation?)
2) Net DIP production within Corsica indicates system heterotrophy (mining P from sediments or transforming PP inputs?)
3) Corsica appears to import substantial DIN from
Chester (transported to middle of estuary, Box 2)
4) Clear regional trends in transport and net fluxes
Problems
1) ~Sparse WQ data – difficult to represent concentration distribution along salinity gradient.
2) Need diffuse source water flow and nutrient loading (TN, NH4, NO3, TON, TP, DIP) for major tribs.
3) Need more point-source loading rates.
4) Need time-series atmospheric loading rates.
5) Need algorithms for estimating water flow and nutrient loading in non-monitored years.
Spatial Distribution of Water Depths
Hypsograph of distribution of system area and volume at various water depths
Implications for benthic production with improved water clarity?
Small increase in Secchi (0.7-1.0 m) yields large increase in photic bottom from 40-90%