utah lake modeling update...division of water quality data collection for hydrodynamic and sediment...
TRANSCRIPT
Utah Lake Modeling Update
Nicholas von StackelbergScience Panel Meeting 12/10/2019
Division of Water Quality
Topics
1) Lake and watershed modeling update
2) Hydrodynamics and sediment transport data
collection update
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Division of Water Quality
Lake Model Framework
3
EFDCHydrodynamics
Sub-Model
SWANWave Model
WASP Water Quality Model
water levelcurrent velocity
orbital velocityradiation stress
NutrientsAlgaeHABs
EFDCSediment Transport
Sub-Model
hydrodynamics
shear stress
Division of Water Quality
Lake Model Status
EFDC WY2006-2018 model built
Water depth and temperature calibrated
Need to build SWAN wind wave model and couple to EFDC
Need to calibrate sediment transport to observed data
WASP WY2006-2015 model built
Coupled to EFDC through hydrodynamic linkage
Need to correct run time issues with sediment diagenesis routine in WASP8
linkage to EFDC
Prescribed fluxes for SOD and sediment nutrients per Hogsett et al. 2019
Annual average atmospheric deposition per Brahney 2019
Model Calibration Report Under development - estimated delivery February 2020
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Division of Water Quality
Watershed Model Status
University of Utah watershed models1) DHSVM - Headwaters
2) SWMM – Urban catchments
3) GoldSim – Water demand systems model
Model framework limitations Upper Provo River watershed above Deer Creek Reservoir not simulated
Headwater nutrient loading not simulated
Nutrient transformations within tributaries not simulated
Limited calibration of SWMM loading due to lack of observed data
Likely will not meet the needs of the Utah Lake
Water Quality Study
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Division of Water Quality
Watershed Model Need
Numeric Nutrient Criteria Development
1) Backcast pre-European settlement nutrient loading Can statistical methods (i.e. Olson and Hawkins 2013, SPARROW) be
employed, rather than mechanistic model?
2) Stressor-response loading analysis Can boundary loadings be adjusted without identifying the source of the
reduction?
Implementation
1) Load allocation scenarios including treated wastewater,
stormwater and agricultural nonpoint source
2) Stressor-response loading analysis
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Division of Water Quality
Modeling Proposed Next Steps
Lake Model
Receive model from University of Utah – estimated
January 2020
Identify gaps and needs (i.e. bioturbation, calcite
scavenging)
Procure consultant support
Watershed Model
Model selection process - summer 2020 after adoption of
nutrient criteria technical framework
Model development – initiate after model selection
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Division of Water Quality
Data Collection for Hydrodynamic and
Sediment Transport Modeling Update
Instrument deployment at 2 sites – continue in spring
1) North Lake Site – near American Fork Marina
2) Provo Buoy Site – near Utah Lake State Park Marina
Sediment cores from 5 sites analyzed by Dr. Goel’s lab
1) Bulk density
2) Organic content
3) Grain size distribution
4) Mineralogy – to be completed
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WQ sonde
Sedimenttrap
ADVADCP
Lake Bottom Lander
Division of Water Quality 9
Turbidity vs. ADV Current Velocity
0
100
200
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400
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600
700
800
0
1
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5
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7
8
9
7/18/2019 7/20/2019 7/22/2019 7/24/2019 7/26/2019 7/28/2019 7/30/2019
Turb
idit
y (F
NU
)
Cu
rre
nt
Ve
loci
ty (
cm/s
)
ADV Velocity Turbidity
Evidence of dependence of turbidity on near bottom water velocity
Division of Water Quality 10
Lake Bottom Turbidity vs. Shear Stress Due to Wave Action
0.000
0.050
0.100
0.150
0.200
0.250
0.300
0.350
0.400
0.450
0.5000
200
400
600
800
1000
1200
9/12/2019 9/17/2019 9/22/2019 9/27/2019 10/2/2019 10/7/2019 10/12/2019
Shea
r St
ress
(N
/m2)
Turb
idit
y (F
NU
)
Provo Buoy Site
Turbidity FNU Shear Stress
Evidence of dependence of turbidity on shear stressAppears to be a threshold shear stress ~ 0.35 N/m2
Division of Water Quality 11
Shear Stress on Lake Bottom
Shear stress due to wave action an order of magnitude greater than due to current velocity
Division of Water Quality 12
Surface vs. Bottom Turbidity
0
200
400
600
800
1000
1200
9/12/2019 9/17/2019 9/22/2019 9/27/2019 10/2/2019 10/7/2019 10/12/2019
Turb
idit
y
4917390 - Provo Buoy Site
Bottom Turbidity (FNU) Buoy Turbidity (NTU)
Offset in turbidity between lake surface and lake bottomLake is well-mixed
Division of Water Quality 13
Turbitity, Chlorophyll a and Phycocyanin at Lake Bottom
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100
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800
0
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7/1/2019 7/6/2019 7/11/2019 7/16/2019 7/21/2019 7/26/2019 7/31/2019 8/5/2019
Turb
idit
y (F
NU
)
Ch
loro
ph
yll a
/BG
A (
RFU
)
North Lake Site
Chlorophyll RFU BGA RFU Turbidity
Evidence of algal and cyanobacterial growth near lake bottom
