Patapsco and Back River HSPF Watershed Model Part II – Water Quality Maryland Department of the Environment
Jan 29, 2016
Patapsco and Back River HSPF Watershed Model
Part II – Water Quality
Maryland Department of the Environment
Introduction
Water Quality DataModel Inputs Calibration ProcedureModel ComparisonsSummary
Water Quality Data
Data Sources Department of Natural Resources
Monthly values for NH3, NO3, TN, PO4, TP, TOC, DO, TSS, Temperature Baltimore City*
Storm event and base flow values for TSS, TOC, TN and TP
* City of Baltimore Comprehensive Wastewater Facilities Master Planning Project
Model Inputs
Atmospheric DepositionSeptic LoadsPoint SourcesManure and Application
Atmospheric Deposition
Deposition is input as NO3 (wet and dry) and NH3
Used CBP time seriesAvg. Annual NO3 7.05 lb/acreAvg. Annual NH3 2.08 lb/acre
Septic LoadsNumber of septic users were calculated on
County basis using Census data compiled by EPA.
Used GIS to allocate to watershed segmentationAssume NO3 loading coefficient of 0.0256
lb/person/day.Assume 60% reduction in NO3Assume 100% retention of Phosphorus
Manure and Application
Animal Counts – Used to calculate Manure Acres which is simulated as an impervious land use
• Manure acres is a derived land use which represents what is susceptible to runoff from confined animals within a model segment.
Animal Animals/ % of time % of time Type An. Unit Confined Unconfined
Beef 1 0.2 0.8 Dairy 0.71 0.8 0.2 Hogs 5 1.0 0.0 Sheep 5 0.5 0.5 Horses 0.855 0.5 0.5 Poultry 5 1.0 0.0
Manure/Mineral Fertilizer Application
Manure Calculations (based on MDA and U of MD recommendations)
Manure Constants Animal N (lb/yr) P (lb/yr)
Beef 113.15 40.15
Dairy 164.25 25.55
Swine 153.30 58.40
Chicken 207.52 84.98
Layers <3 207.52 84.98
Broilers 275 93.5
Sheep 113.15 40.15
Horses 113.15 40.15
Turkeys 185.02 76.78
Runoff Losses and Volatilization Factors
Animal Type Storage type % not volatilized or not
lost to runoff (Retained for Application)
N P
Beef Stored 0.30 0.85
Dairy Stored 0.40 0.85
Swine Stored 0.25 0.85
layers >3 Stored 0.69 1.0
layers <3 Stored 0.69 1.0
Broilers Stored 0.60 1.0
Turkeys Stored 0.53 1.0
Pasture - Beef Pasture 0.30 0.85
Dairy Pasture 0.70 0.85
Swine Pasture 0.25 0.85
Layers < 3 Pasture 0.69 1.0
Layers < 3 Pasture 0.69 1.0
Broilers Pasture 0.60 1.0
Turkeys Pasture 0.53 1.0
Calibration Procedure
Focus on predominant land usesCalibrate EOS loads to literature valuesCalibrate urban loads to Event Mean
Concentrations (EMCs)Time series overlay
Unit Loading Rates (Literature Values)
Literature Sources:Jones Falls Water Quality Management Plan, Loch Raven Water Quality Management Plan, Baltimore County NPDES 2000, Harford County NPDES 1999 and 2000, City of Baltimore NPDES 1999, Center for Watershed Protection and Ken Staver (University of MD).
Areamin avg max min avg max min avg max
Urban 175,977 19 157 394 5.31 6.62 7.71 0.55 0.68 0.89Crop 30,765 148 234 366 6.59 14.50 30.00 0.21 0.59 0.82Pasture 11,382 148 277 491 3.74 5.34 6.80 0.12 0.39 0.66Forest 83,521 48 110 333 0.86 1.91 3.40 0.09 0.12 0.20
Loading Rates (lbs/ac/yr)Sediment TN TP
Patapsco/Back Estimated Average Annual Loads and Percent Contributions
Load = Loading Rate x Area
Urban 58% 175,977 59% 13,793 58% 1,164,967 79% 119,664Crop 10% 30,765 15% 3,601 22% 446,087 12% 18,151Pasture 4% 11,382 7% 1,574 3% 60,780 3% 4,439Forest 28% 83,521 20% 4,598 8% 159,524 7% 10,022Septic 8% 168,105Total 301,644 23,565 1,999,463 152,277
Area(acres) Sediment (tons) TN (lbs) TP (lbs)
Estimated and Final Model EOS Loads
Estimated Model OutputTSS (Ton/yr) 23,565 23,861TP (lb/yr) 1,999,463 2,405,247TN (lb/yr) 152,277 164,676
Total Watershed EOS Loads
Urban EMCs
HSPF EMC comparisons with MD NPDES TN EMCs
resi
dent
ial
com
mer
cial
All
0
1
2
3
4
5
6
mg/
L
residential
commercial
industrial
all
Gwynns
jones
Patapsco
NURP-Residential
NURP-commercial
NURP-industrial
indu
stri
al
Gw
ynns
F
alls
Jone
s F
alls
Pat
apsc
o
NU
RP
HSPF EMC comparison with MD TP EMCs
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8m
g/L
Residential
Commercial
Industrial
All
Gwynns
Jones
Patapsco
NURP-residential
NURP-commercial
NURP-industrial
resi
den
tial
com
mer
cial
Indu
stria
l
all
Gw
ynns
Fal
ls
Jone
s Fa
lls
Pat
apsc
o
NU
RP
HSPF EMC Comparisons with MD TSS EMCs
0
20
40
60
80
100
120
140
160
180
200m
g/L
Residential
Commercial
Industrial
All
Gwynns
Jones
Patapsco
NURP-residential
NURP-commercial
NURP-industrial
resi
den
tial
com
mer
cial
indu
stria
l
all
Gw
ynns
Fal
ls
Jone
s Fa
lls
Pat
apsc
o
NURP
Jones Falls Water Quality Calibration
Calibration at Station JON0184 Parameters calibrated:
DO, Temperature, TOC, TSS, PO4, TP, NH3, NO3, ChlA and TN
Dissolved Oxygen - Jones Falls
6
7
8
9
10
11
12
13
14
15
16
01/01/92 01/01/93 01/01/94 01/01/95 01/01/96 01/01/97 01/01/98
Time
mg
/L simulated
observed
Temperature - Jones Falls
0
5
10
15
20
25
30
01/01/92 01/01/93 01/01/94 01/01/95 01/01/96 01/01/97 01/01/98
Time
Deg
C simulated
observed
Total Suspended Solids - Jones Falls
0
20
40
60
80
100
120
140
160
1800
1/0
1/9
7
02
/01
/97
03
/01
/97
04
/01
/97
05
/01
/97
06
/01
/97
07
/01
/97
08
/01
/97
09
/01
/97
10
/01
/97
11
/01
/97
12
/01
/97
Time
mg
/L
simulated
DNR
Balt City Storm
Balt City Grab
Total Phosphorus - Jones Falls
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
01
/01
/97
02
/01
/97
03
/01
/97
04
/01
/97
05
/01
/97
06
/01
/97
07
/01
/97
08
/01
/97
09
/01
/97
10
/01
/97
11
/01
/97
12
/01
/97
mg
/L Simulated
DNR
Balt City Grab
Balt City Storm
Total Nitrogen (mg/L) - Jones Falls
0
1
2
3
4
5
1/1
/97
2/1
/97
3/4
/97
4/4
/97
5/5
/97
6/5
/97
7/6
/97
8/6
/97
9/6
/97
10/7
/97
11/7
/97
12/8
/97
Time
mg
/L
simulated
DNR
Balt City storm
Balt City grab
Total Organic Carbon - Jones Falls
0
2
4
6
8
10
12
14
16
18
20
01
/01
/97
02
/01
/97
03
/04
/97
04
/04
/97
05
/05
/97
06
/05
/97
07
/06
/97
08
/06
/97
09
/06
/97
10
/07
/97
11
/07
/97
12
/08
/97
Time
mg
/l
DNRsimulatedbalt city grabbalt city storm
Chl A - Jones Falls
0
2
4
6
8
10
12
14
16
18
01/01/92 01/01/93 01/01/94 01/01/95 01/01/96 01/01/97 01/01/98
mic
ro g
ram
s/L simulated
DNR Core
Patapsco (Hollofield) Branch Water Quality Calibration
Calibration at Station PAT0285 Parameters calibrated:
DO, Temperature, TOC, TSS, PO4, TP, NH3, NO3, ChlA and TN
Dissolved Oxygen - Patapsco at Hollofield
6
7
8
9
10
11
12
13
14
15
16
01/01/1992 01/01/1993 01/02/1994 01/03/1995 01/04/1996 01/04/1997 01/05/1998
Time
mg
/L simulated
DNR
Water Temperature - Patapsco at Hollofield
0
5
10
15
20
25
30
01/01/1992 12/28/1992 12/25/1993 12/22/1994 12/19/1995 12/15/1996 12/12/1997
Time
Deg
C simulated
DNR
Total Suspended Solids - Patapsco at Hollofield
0
100
200
300
400
500
600
Jan-
97
Fe
b-9
7
Ap
r-9
7
Ma
y-9
7
Jul-9
7
Se
p-9
7
Oct
-97
De
c-9
7
Time
mg
/L
MDE
Balt City Storm
Balt City Grab
DNR
CBP
Total Phosphorus - Patapsco at Hollofield
0
0.2
0.4
0.6
0.8
1
1.2
1.4Ja
n-9
7
Fe
b-9
7
Ap
r-9
7
Ma
y-9
7
Jul-9
7
Se
p-9
7
Oct
-97
De
c-9
7
Time
mg
/L Balt City GrabSimulatedBalt City StormCBPDNR
Total Nitrogen - Patapsco at Hollofield
0
2
4
6
8
10
12
14
16
18Ja
n-9
7
Fe
b-9
7
Ap
r-9
7
Jun-
97
Jul-9
7
Se
p-9
7
Oct
-97
De
c-9
7
Time
mg
/L
DNRsimulationBalt City GrabBalt City StormCBP
Total Organic Carbon - Patapsco at Hollofield
0
10
20
30
40
50
60
70
8001
/01/
1997
02/0
1/19
97
03/0
4/19
97
04/0
4/19
97
05/0
5/19
97
06/0
5/19
97
07/0
6/19
97
08/0
6/19
97
09/0
6/19
97
10/0
7/19
97
11/0
7/19
97
12/0
8/19
97
Time
mg
/L
simulated
balt city grab
balt city storm
DNR
Chl A - Patapsco at Hollofield
0
2
4
6
8
10
12
14
16
18
20
01/01/1992 01/01/1993 01/02/1994 01/03/1995 01/04/1996 01/04/1997 01/05/1998
Time
mic
ro g
ram
s/L
simulated
dnr
Summary/Comparisons
Unit loads, EOS and Delivered loads compared to existing studies
Discussion of model loads and comparison
Comparison of Unit Loading RatesArea
min avg max min avg max min avg maxUrban 175,977 19 157 394 5.31 6.62 7.71 0.55 0.68 0.89MDE(93-97) 133 6.98 0.74CBP(93-97) 382 13.81 2.14Forest 83,521 48 110 333 0.86 1.91 3.40 0.09 0.12 0.20MDE(93-97) 126 2.62 0.21CBP(93-97) 685 2.50 0.14Crop 30,765 148 234 366 6.59 14.50 30.00 0.21 0.59 0.82MDE(93-97) 365 20.22 0.29CBP(93-97) 2,383 21.21 1.42Pasture 11,382 148 277 491 3.74 5.34 6.80 0.12 0.39 0.66MDE(93-97) 221 7.95 0.19CBP(93-97) 1,087 11.84 1.91
Loading Rates (lbs/ac/yr)Sediment TN TP
Total Average Annual EOS Loads Summary
To Harbor To Back River Total EOS To Harbor To Back River Total EOS To Harbor To Back River Total EOS
Area (Ac) 266,888 34,785 301,673 266,823 34,976 301,769 255,952 46,851 302,803Flow (MG/yr) 178,865 23,181 202,046 174,678 23,937 198,616 142,386 33,208 175,594Sed (Ton/yr) 21,736 2,125 23,861 40,248 3,365 43,613 91,710 7,298 99,008TP (Lb/yr) 142,564 22,112 164,676 375,095 98,091 473,186TN (Lb/yr) 2,178,046 227,201 2,405,247 3,154,964 684,778 3,839,742
HSPF MDE (93-97) SWMM MDE (93-97) HSPF CBP (93-97)
Total Delivered Loads Summary
Patapsco Back Total Patapsco Back TotalTotal Area (Ac) 266,888 34,785 301,673 255,952 46,851 302,803Total Avg Flow (MG/yr) 179,242 23,181 202,423 142,386 33,208 175,594Total Sediment (Ton/yr) 24,651 2,125 26,776 89,407 7,298 96,705Total TP (Lb/yr) 145,967 22,112 168,079 382,131 98,091 480,222Total TN (Lb/yr) 2,475,009 227,201 2,702,210 3,083,647 684,778 3,768,425
Total Delivered Load from WatershedMDE(93-97) CBP(93-97)
Back River Comparisons
MDE-HSPFBALTIMORE
COUNTY - SWMMMDE-SWMM CBP-HSPF
TSS (Ton/yr) 2,125 3,124 3,554 7,928TP (lb/yr) 22,112 21,888 98,091TN (lb/yr) 227,201 308,166 684,778
Comparison of CBP and MDE Model
Model ScaleHydrology CalibrationWater Quality CalibrationUrban Calibration
CBP Segmentation
MDE Segmentation
Hydrology Calibration
Water Quality Calibration
Urban Calibration
NPDES Storm Water Data vs. National Urban Runoff Program (NURP) Data
CBP reductions to Urban Loads- Reductions to Urban Loads of 15% TN and 30% TP*
* Based on numbers from Urban Watershed Group
Summary
MDE hydrology calibrated to 3 gages. CBP model hydrology calibrated to 1 gage.
MDE water quality calibrated to 4 gages. CBP model water quality calibrated to 1 gage.
MDE urban land use calibrated to local NPDES data. CBP calibrated to NURP data.
It can be concluded that the final load differences between the MDE and CBP models are due to these factors.