Point Source Loads and Decision Criteria for Toxics Modeling Baltimore Harbor TMDL Stakeholder...

Point Source Loads and Decision Criteria for Toxics

Modeling

Baltimore Harbor TMDL Stakeholder Advisory Group

September 10, 2002

Overview

• Data Sources

• Model Constraints

• Decision Criteria

• Calculations and Evaluations

• Conclusions

Data Source Evaluation

• MDE reviewed several sources of data– Permit Compliance System (PCS)

• EPA NPDES compliance database

– Toxic Release Inventory (TRI)• Right to Know database of sources and quantities

– Toxic Loadings Release Inventory (TLRI)• CBP developed database

Data Source Evaluation

• PCS Data – – Data is generated by NPDES permit holders by

submitting Discharge Monitoring Reports on a monthly or quarterly basis

– Data collected by MDE and entered into EPA maintained database

– Measured Values

Data Source Evaluation

• Toxics Release Inventory – Data generated by industry to comply with

Right to Know Act– Data collected by MDE and entered into EPA

database– Data not available for all sources in Harbor

watershed – variable reporting thresholds – Data not measured in many cases – engineering

calculations or mass balance estimates

Data Source Evaluation

• Toxics Loading Release Inventory (1999)– Database generated by Chesapeake Bay

Program– Data is for Major (>0.5MGD) discharges– Source of Data is PCS

Model Constraints

• CH3D Hydrodynamics Model – Point sources are entered into a model grid – Individual sources create new sets of interaction

equations – these consume significant computer memory and lead to increased model run times

– Sensitivity of the model to flow • Low flows do not significantly influence

hydrodynamics

– Data requirements – (i.e., complete data sets)

Decision Criteria• Point Sources and load estimations

– MDE calculated PS loads using two techniques

estimated load = (maximum concentration * average flow)

estimated load = (average concentration * average flow)

In cases with detection limits reported - the DL was assumed as the maximum concentration

• Comprehensive goals were established• Capture 95% of the PS load and

• Capture sources that constitute >1% of total daily PS load

Source Criteria for Small Flows

• The Harbor was separated into its five major regions – Inner Harbor, Middle Branch, Curtis Creek, Bear Creek, and the Middle/Outer Harbor

• Within these regions, flows were ranked based on the % of total average daily point source flow

• Sources that contributed <5% of total flow for a given region were excluded from the model

• However, sources that constituted >5% of total point source flow for a given region and were <0.5 MGD were excluded from the model

Source Criteria for TSS

• The Harbor was separated into its five major regions – Inner Harbor, Middle Branch, Curtis Creek, Bear Creek, and the Middle/Outer Harbor.

• Within these regions, TSS loads were ranked based on the % of total average daily PS load

• Sources that contributed <5% of total TSS load for each region were excluded from the model.

• However, sources that constituted <5% of total point source load for each region and were >500 lbs/day (1% of the total average daily PS load to the entire Harbor) were included in the model.

Criteria for Zn, Pb, and Cr

• The Harbor was separated into its five major regions – Inner Harbor, Middle Branch, Curtis Creek, Bear Creek, and the Middle/Outer Harbor.

• Within these regions individual metals ranked based on the % of total average daily point source load – Each region was dominated by a single source

• For Cr, Zn, and Pb sources baselines were established at 1% of the total average daily load – Sources that constituted 100% of the load in regions and were

under the baseline were excluded from the model.

Load Calculation Overview

• PCS Data queried and sorted • Average monthly flow rates selected

– For industries with quarterly sampling the flow value collected was used for the entire quarter

• Monthly conc. values defined (max and ave.)– For industries with quarterly sampling the conc. value

collected was used for the entire quarter

• Daily load values calculated• Average daily loads calculated and evaluated with

decision criteria

Example Calculation

Load (lb/day) = Concentration max (mg/l) * Flow avg (MGD) * 8.345

Where 8.345 is the conversion factor from mg/L and MGD to lb/day

Industry NPDES Outfall Date TSS max (mg/l) Flow avg (MGD) TSS m/a (lb/day)ACME Widgets MD…. 1 03/31/1998 10 0.007 0.55ACME Widgets MD…. 1 06/30/1998 20 0.007 1.10ACME Widgets MD…. 1 09/30/1998 34 0.003 0.82ACME Widgets MD…. 1 12/31/1998 8 0.001 0.06

Average 0.63

Example Evaluation TableBaltimore Harbor Point Source - TSS Criteria

Industry Region NPDES Outfall TSS avg (lb/day)** TSS m/a (lb/day)* Regional m/a (%)* Regional (%)**

Beth Steel Bear Creek MD0001201 014A 11363.171 12774.401 100.00 100

Erachem Comilog (Chemetals) Curtis Creek MD0001775 001A 7.092 12.328 47.47 46.35CSX Curtis Creek MD0057371 001A 4.530 8.007 30.83 29.61US Gypsym (total) Curtis Creek MD0001457 001/2A 1.338 2.935 11.30 8.75Millenium-HPP Curtis Creek MD0066206 001A 2.341 2.703 10.41 15.30

MTA-Wash.Blvd Middle Branch MD0051047 001A 8.086 16.303 57.27 57.09Carr-Lowrey Glass (total) Middle Branch MD0001414 003/8A 2.396 4.700 16.51 16.92Constellation-Spring Gardens (total) Middle Branch MD0001538 004/5/6/7A 2.118 3.524 12.38 14.95Locke Insulators Middle Branch MD0002763 001A 1.323 3.212 11.28 9.34Trigen-Spring Gardens Middle Branch MD0061930 001A 0.221 0.557 1.96 1.56Trigen-Saratoga Middle Branch MD0066877 001A 0.020 0.170 0.60 0.14

Millenium Hawkins (total) Middle Harbor MD0001261 001/2/3A 5392.096 20437.804 73.76 47.94Patapsco WWTP Middle Harbor MD0021601 001A 5267.412 6465.947 23.34 46.83Cox Creek WWTP Middle Harbor MD0021661 001A 477.994 666.604 2.41 4.25Millenium-St.Helena Middle Harbor MD0001279 002A 30.804 48.571 0.18 0.27Chevron Products Middle Harbor MD0001449 001A 26.621 24.792 0.09 0.24Hawkins Point Landfill (total) Middle Harbor MD0061417 001/2/3A 12.527 18.233 0.07 0.11Millenium-HPP (total) Middle Harbor MD0066206 002/3A 7.612 11.421 0.04 0.07Sasol (Condea Vista) Middle Harbor MD0000540 001A 10.725 10.725 0.04 0.10Millenium-Quarantine Middle Harbor MD0057657 001A 9.484 9.690 0.03 0.08Dundalk Marine Terminal Middle Harbor MD0066818 001A 8.134 8.134 0.03 0.07Soil Safe Middle Harbor MD0066141 001A 1.850 3.254 0.01 0.02Baltimore Compositing Middle Harbor MD0061875 001A 1.598 2.257 0.01 0.01Baltirmore Marine Industries (total) Middle Harbor MD0001180 001/18A 0.000 0.000 0.00 0.00

TASR (total) Northwest Branch MD0001341 001/3A 705.406 1566.816 99.58 99.85

Fort Mchenry Shipyard Northwest Branch MD0002267 001A 5.2067 0.33 0.00Trigen-Central Northwest Branch MD0066249 001A 0.359 0.692 0.04 0.05Baltimore Arena Northwest Branch MD0063100 001A 0.701 0.701 0.04 0.10

Beth Steel (total) Old Road Bay MD0001201 017/101A 606.943 748.082 100.00 100.00

Calculation - Load (lb/day) = Concentration max (mg/l) * Flow avg (MGD) * 8.345*Calculations conducted with maximum concentration and average flow**Caclulations conducted with average concentration and average flow

Conclusions

• Load data along with the evaluation criteria was sent to point source dischargers during the last week of August

• We have received comments and expect to receive more – further discussions will follow to finalize load values

Nutrients Point Source Loads

Overview

• Data

• Sources

• Conclusions

Data for Modeling

• MDE nutrient database prepared for the Chesapeake Bay Program eutrophication model. – PCS data plus monthly operating reports and permit application data

Modeling Point Sources

• Based on established MDE nutrient TMDL protocols – ALL point sources will be included in the

model and – ALL point sources will receive allocations

• However, ONLY major (>0.5 MGD) sources will be subject nutrient reductions

PS Calculation

• PCS Data queried, sorted, and downloaded to MDE database

• Average monthly flow rates selected

• Average monthly conc. values selected

• Daily load values calculated

0

1,000,000

2,000,000

3,000,000

4,000,000

5,000,000

6,000,000

7,000,000

Flow (MG/yr) TSS (Ton/yr) TP (lb/yr) TN (lb/yr)

DRAFT Nutrients PS and NPS Comparison

NPS Loads

PS Loads

Conclusions

• PS Load data – external review expected within next few weeks

• Fewer PS locations allow for inclusion of all into model framework