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The Disconnection Between Limnological Information and the Phosphorus “Total
Maximum Daily Loads” (TMDL) Analysis for Onondaga Lake
Steven Effler, Susan O’Donnell,
David Matthews, Carol Matthews,
David O’Donnell,
Martin Auer, and
Emmet Owens
innovative
engineering &
t
echnology
Eutrophy at Onondaga Lake
– poor clarity– rapid hypolimnetic DO loss– fall DO depletion– fish exodus– high summer average
epilimnetic [TP] (> 50 µgP·L-1)
the central role of phosphorus (P) loading
oligo-mesotrophic before European settlement
cultural eutrophication has lead to– phytoplankton blooms– nuisance cyanobacteria
What are Loads?
lake
inflow outflow
load = inflow X concentration in the inflowmass/time volume/time mass/volume
load
represented as throughout talk
Types of Loads
point loads
non-point loads
rural
urban
What is a TMDL Analysis?
determine the loading rate that will help meet an established goal
current load(all sources)
[TP] >50 µgP·L-1
current in-lake
concentration
[TP] = 20 µgP·L-1
established goal
?
TotalTMDL
MaximumDaily Load
TP guidance value for mid-May to mid Sept.
a quantitative framework to guide
rehabilitation
TMDL Components[TP] = 20 µgP·L-1
guidance value
WLA = Waste Load Allocation = METROLA = allocation for non-point sources and
natural background =TribsMOS = margin of safety
WLA/METRO
LA/Tribs
TMDL = WLA + LA + MOS
Important Features of TMDL Analysis
accommodation of – important system specific characteristics– critical environmental conditions– recurring features of seasonality
consistency with format of standard– TP guidance value; summer average (mid-May to
mid-September) epilimnetic concentration of 20 µg·L-1 (upper bound mesotrophy)
model: quantitative linkage between external loads and lake concentrations
– synthesis of understanding of the system – behavior of phosphorus (P)
NYSDEC TMDL Analysis 1998
based on annual loads reported from Onondaga County monitoring program, 1990-1995
TMDL analysis calls for 50% reduction in Tribs 90% reduction in METRO
TMDL TP Load (2012)
METRO25%
Tribs65%
MOS 10%METRO Effluent
Tribs.32%
ME bypass
total METRO = 68%
prevailing TP (TMDL) loading
Model Framework Used in TMDL Analysis
TP loadingMETRO and tribs.
UML
LML
settlingmixing
UML = upper mixed layer, ~epilimnionLML = lower mixed layer, ~hypolimnion
outflow/Seneca River
settling sediment release
P TMDL/Management Plan/ACJphase I - composed of 3 stages (1998-2012)
– continuing in-lake discharge
Stage Starting Year METRO [TP] CSO’s Flow
– *METRO reductions have feasibility issues– also a LA (tributary) reductions of 50% during phase I
phase I I - update TMDL analysis in 2009
I 1998 550 µgP·L-1 62% reduction
II 2006 120 µgP·L-1 85% reduction
III 2012 20 µgP·L-1* no further reduction
Critical Evaluation of P TMDL for Onondaga Lake
Seneca River as source to the lake lake flushing “plunging inflows” contrasting bioavailability of particulate
phosphorus (PP) sources analytical problems loads/targets and feasibility synthesis of above effects to estimate effective
phosphorus loading
( )
previously presented information
presentation outline
issues addressed in this talk
Independent Long-Term Monitoring Program
R iver
O utle t
Lake
U
D
O no nd a g a La ke
Syra c use
O no nd a g a C re ek
U= up strea mD= d ownstrea m
D
U
Critical Evaluation of P TMDL for Onondaga Lake
the Seneca River as source to the lakelake flushing“plunging inflows”contrasting bioavailability of (PP) sourcesanalytical problemsloads/targets and feasibilitysynthesis of above effects to estimate
effective phosphorus loading
presentation outline
issues addressed in this talk
outlet - bi-directional flow
lakeriver
sediments
Stratified River Flow
bi-directional/stratified flow in outlet
outlet - normal
lake
sediments
O utle t
Lake
U
D
QI/S
salinity ~ 0.35 °/°°
salinity ~1.1 °/°°
man made causes– lowering lake water surface elevation to that of river– salinity pollution of lake
net river flow into lake called QI/S throughout talkwater quality concerns – P load to lake
– QI/S has not been quantified– river rich in bioavailable P
Estimate(s) of Seneca River Inflow (QI/S)
conducted chloride mass balance around the lake/river system for 4 years
four year summer averagecompared to METRO
QI/S QMETRO
river summer avg [TP]>60 µgP·L-1
future METRO summer avg [TP]= 20 µgP·L-1
estimates of QI/S varied year to year and seasonallyfirst approximation of summer average QI/S
Critical Evaluation of P TMDL for Onondaga Lake
the Seneca River as source to the lakelake flushing“plunging inflows”contrasting bioavailability of (PP) sourcesanalytical problemsloads/targets and feasibilitysynthesis of above effects to estimate
effective phosphorus loading
presentation outline
issues addressed in this talk
Interplay Between Lake Flushing Rate and Timing of the TP Guidance Value
flushing rate = inflow rate ÷ lake volume
high flushing rate – entering water remains in lake only a short time
inflow outflow
UMLLML
what is flushing rate?
Implications of Lake Flushing: Formation of a Lake Response Curve
response
tracer injected for one monthmodel run
repeated each month 30 year inflow record formation of lake “response
curve”
summer average (mid-May through mid-Sept.,timing of guidance value) epilimnetic concentration of tracer calculated from model output
Implications of Lake Flushing: Response Curve for METRO Loads
response curve driven by high flushing and timing of TP guidance value
effect ofinterannual
variation in runoff
critical loading interval April-August instead of annual loading ratesminor impact of loads received early fall through following spring time averaging interval of METRO permit (12 months) not protective interannual variations of Q are important
critical loading interval April-August instead of annual loading ratesminor impact of loads received early fall through following spring time averaging interval of METRO permit (12 months) not protective interannual variations of Q are important12 month averaging appropriate for lakes with low flushing rates
Implications of Lake Flushing: Response Curve for METRO Loads
response curve driven by high flushing and timing of TP guidance value
effect ofinterannual
variation in runoff
Effect of Seasonality of TDP Loading Rate
tributary loading rates are lower for April – August compared to annual loads
critical loading interval April-August instead of annual loading rates
Critical Evaluation of P TMDL for Onondaga Lake
the Seneca River as source to the lakelake flushing“plunging inflows”contrasting bioavailability of (PP) sourcesanalytical problemsloads/targets and feasibilitysynthesis of above effects to estimate
effective phosphorus loading
presentation outline
issues addressed in this talk
Lake
more dense
Density and Plunging Inflows
Inflowless dense
Entry of Inflows
density () is a function of temperature (T) and salinity (S)depth inflow enters is a function of density difference
(T,S) between an inflow and the lake
plunging underflow
Density and Plunging Inflows
Lake
more dense
Inflowless dense
large density difference (T,S) leads to plunging inflows
Differences in Density
J F M A M J J A S O N D
T
/S
(kg·
m-3
)
-2
0
2
4 Onondaga Cr.
METRONinemile
Lake
more dense
Inflowless dense
Inflow Entry and Lake Stratification
UML
metalimnion
H
metalimnetic peak caused by
plunging inflow
Density and Plunging Inflows
stratification model
Stratification Model for Plunging Inflows
UML
LML
TMDL model
mixed (UML)
H
metalimnionplunging sub-model
Model Performance
Stratification Model Application
Density and Plunging Inflows
M ETR O
M etalim nion
O nondaga& N inem ile
Creeks
M eta lim nion
Critical Evaluation of P TMDL for Onondaga Lake
the Seneca River as source to the lakelake flushing“plunging inflows”contrasting bioavailability of (PP) sourcesanalytical problemsloads/targets and feasibilitysynthesis of above effects to estimate
effective phosphorus loading
presentation outline
issues addressed in this talk
Bioassay Setup
Bioavailability
algal bioassay experiments to determine bioavailability of PP
Bioavailability of P According to Sources
dissolved P particulate P
TP
Bioavailability
Bioavailability of P According to Sources
all forms of P are not equally available to support algal growth
TP
highsettling
lowsettling
Particulate P
Bioavailability
organic P
P available for algal growth
dissolved P
inorganic P
Bioavailability: Contrasting Contributions of TDP to TP
total dissolved phosphorus (TDP) is bioavailable TDP/TP ratio as an indicator
BioavailabilitySite
OC-u OC-d NMC LC METRO SenRiv
Rat
io T
DP
/TP
0.0
0.2
0.4
0.6
0.8
tribs
SiteOC-u OC-d NMC METRO
Bio
avai
labl
e P
(µgP
·gT
SS
-1)
0
2000
4000
6000
8000
10000
12000
Contrasting Bioavailablity of PP
Bioavailability
consistent with literature
tribs
SiteOC-u OC-d NMC METRO
Rat
e(d
-1)
0.0
0.1
0.2
0.3
0.4
0.5
Contrasting Bioavailability Rates of PP
Bioavailability
consistent with literature
tribs
Contrasting Associations of Bioavailable PP and Settling
Site
Onon. Ck. upstream
Onon. Ck. downstream
Ninemile Ck.
METRO
P Associations
inorganic
organic/inorganic
inorganic
organic
Bioavailability
widely different deposition rates of bioavailable PP
Settling
fast
medium
fast
slow
Critical Evaluation of P TMDL for Onondaga Lake
the Seneca River as source to the lakelake flushing“plunging inflows”contrasting bioavailability of (PP) sourcesanalytical problemsloads/targets and feasibilitysynthesis of above effects to estimate
effective phosphorus loading
presentation outline
issues addressed in this talk
Analytical Issue TP Issuefailure to correct for turbidity during the TP analysis leads to false high TP loads
no turbidityspectrophotometer
cuvette
high turbidity
Analytical Issue: Effect on TP Loads
failure to correct for turbidity during the TP analysis leads to false high TP loads
Annual Load Estimates for 2000
Critical Evaluation of P TMDL for Onondaga Lake
the Seneca River as source to the lakelake flushing“plunging inflows”contrasting bioavailability of (PP) sourcesanalytical problemsloads/targets and feasibilitysynthesis of above effects to estimate
effective phosphorus loading
presentation outline
issues addressed in this talk
Tributary TP Loads: Prevailing versus Literature
UAL = unit area loads, kgP·km-2·yr-1
Sites Literature
lake tributaries are not rich targets 50% reduction goal ?
common literature
rangesrural
urban
Critical Evaluation of P TMDL for Onondaga Lake
the Seneca River as source to the lakelake flushing“plunging inflows”contrasting bioavailability of (PP) sourcesanalytical problemsloads/targets and feasibilitysynthesis of above effects to estimate
effective phosphorus loading
presentation outline
issues addressed in this talk
What is Effective P Loading?
Synthesis
effective P loading is that portion of the total loading that will support algae growth in the lake
M eta lim nion
“e ffective”tp load
apparent TP load algal
growth
Effective TDP Loading: Prevailing (kg·d-1)
Synthesis
annual
productiveseason
to productivelayers
effective load
apparent loadMETRO Tributaries
Effective PP Loading: Prevailing (kg·d-1)
unblanked
annual
Synthesis
METRO
productiveseason
bioavailable
notdeposited
to productivelayers
effective load
apparent load Tributaries
TMDL TP Contributions
METRO68%
tribs.32%
NYSDEC prevailing TP (TMDL) loading
realistic prevailing loading conditions
Synthesis
Effective P Loading Contributions
tribs.14%
METRO86%
without river
METRO80%
tribs.13%
Sen. Riv.7%
with river
bypass
METROtribs.
Sen. Riv.
Futuristic Partitioning “Effective” P Loading Contributions
stage III: METRO limit (20 µgP·L-1), other prevailing
manageable
target richness
Synthesis
only fraction of trib. load subject to management
ConclusionsNYSDEC TMDL Analysis is fatally flawed in the following
ways...
R iver
O utle t
Lake
TMDL Analysis Did Not Include
1. Seneca River load
QI/S
conclusions
outlet - bi-directional flow
lakeriver
sedimentsoutlet - bi-directional flow
lakeriver
sediments
2. implications of rapid lake flushing
inflow outflow
UMLLML
conclusions
12 month averaging for METRO effluent is not protective of the lake
TMDL Analysis Did Not Consider
3. implications of the plunging inflows phenomenon
Lake
more dense
Inflowless dense
UML
metalimnion
H
conclusions
model applied was an inappropriate framework
TMDL Analysis Did Not Consider
4. contrasting bioavailability and settling characteristics of PP for different sources
conclusions
TMDL Analysis Did Not Consider
highsettlinghighsettling
lowsettlinglowsettling
Particulate P
organic P
dissolved P
inorganic Pmodel applied was an inappropriate
framework
4. TP tributary concentrations of Onondaga County monitoring program are false high
no turbidity high turbidity
conclusions
TMDL Analysis Did Not Recognize
5. target richness and feasibility of non-point load reduction goals
conclusions
50% non-point loading reduction goals are not feasible
rural
urban
TMDL Analysis Did Not Fully Consider
METRO
6. apparent verses effective loads
conclusions
TMDL Analysis Did Not Consider
effective load
apparent load
short-comings caused understatement of METRO’s role and overstatement of
tributaries role
METRO Tributaries
Important Features of TMDL Analysis
accommodation of – important system specific characteristics– critical environmental conditions– recurring features of seasonality
model – quantitative linkage between external loads and lake concentrations– synthesis of understanding of the system – behavior of phosphorus (P)
Conclusionsexisting P TMDL analysis developed by the NYSDEC
cannot be considered a reliable basis to guide rehabilitation of the lake’s related problems
conduct a valid P TMDL analysis for Onondaga Lake now (don’t wait until 2009)
develop a plan to eliminate the Seneca River inflowreconsider management strategies
Recommendations