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Water Quality

Pollutant Loading Model


The template for this model was developed by the Center for Watershed Protection (CWP). Input summaries for the Bronx River CSO's were prepared by NRG staff.

Pollutant loading rates were generated for the five CSO areas (HP-004, HP-007, HP-008, HP-009, HP-010) that drain to the Bronx River. Combined sewers HP-008 and HP-010 do not overflow due to the ability of the combined sewer system to handle both small and large storm events without discharging to the river.

To read more about this model, download a PDF of the Pollution Loading Model Summary (146 KB).

Bronx County CSO Drainage Areas

Bronx River CSO sheds in Bronx County

Land Use Statistics

CSO Total Area (Acres) Impervious Area (Acres) % Impervious
HP-004 506 418 82.70%
HP-007 1314 1036 75.10%
HP-008 211 161 76.60%
HP-009 403 285 70.90%
HP-010 218 78 36.10%

Combined Sewer Outfall area and impervious area calculations generated from EMERGE data.

Summary of Loading Rates

A breakdown of loading rates by source for each CSO is given in Appendix 1 of the Pollution Loading Model Summary (PDF, 146KB).

CSO Area (acres) Impervious (%) TN (lb/yr) TP (lb/yr) TSS (lb/yr) FCOL (billion/yr)
HP-004 516 82.7 4,996 694 246,250 781,190
HP-007 1,305 75.1 12,617 1,704 636,700 1,785,689
HP-008 213 76.6 1,955 267 102,950 130,329
HP-009 404 70.9 3,856 519 198,015 744,834
HP-010 144 36.1 1,086 146 70,650 86,758

Summary of pollutant loading (TN - total nitrogen, TP - total phosphorus, TSS - total suspended solids, FCOL - fecal coliform) from each combined sewer outfall draining to the Bronx River.


Land use data was obtained through the PLUTO system, a GIS database comprised of land use and infrastructure data developed by the New York City Planning Department.

A fine resolution (3 x 3 ft.) land cover data set was used to calculate impervious, grass, and tree cover statistics within these land uses. This EMERGE layer was generated by the USDA Forest Service. The raster data set is classified by cover type (tree, grass, impervious surface, or unclassified). Further descriptions of these classifications can be found in Myeong, 2001.

Other GIS data layers including road networks, watershed/sewershed delineation, and orthophotography were acquired from the NYC DPR GIS database.


Pollution Loading Model Summary (PDF, 146 KB, includes Appendices).

Land Use Data Summary for HP-004 (PDF, 44 KB)

Land Use Data Summary for HP-007 (PDF, 42 KB)

Land Use Data Summary for HP-008 (PDF, 42 KB)

Land Use Data Summary for HP-009 (PDF, 41 KB)

Land Use Data Summary for HP-010 (PDF, 39 KB)

Model Input Summary for HP-004 (PDF, 427 KB)

Model Input Summary for HP-007 (PDF, 428 KB)

Model Input Summary for HP-008 (PDF, 423 KB)

Model Input Summary for HP-009 (PDF, 423 KB)

Model Input Summary for HP-010 (PDF, 423 KB)

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