Development of Land-based Pollution Sources Inventory
for the Gulf of Maine Regional Watershed

Principal Investigators:

Mr. Percy Pacheco
Mr. Dan Farrow
Dr. Ranjan Muttiah
Dr. Raghavan Srinivasan

Cooperators:

Pollution Sources Characterization Branch
Strategic Environmental Assessments Division
National Oceanic and Atmospheric Administration (NOAA)
Silver Spring, Maryland

Coastal Programs Division
Office of Ocean and Coastal Resource Management
NOAA, Silver Spring, Maryland

Blackland Research Center
Texas Agricultural Experiment Station
Temple, Texas

Gulf of Maine Council on the Marine Environment
Augusta, Maine

U.S. State Department
Washington, D.C.

Period:

October 1994 - October 1996

Budget:

$125,000.00

Objective . Methodology . Results

Comments:

Please send your comments/questions by email to Dr. Ranjan Muttiah or Dr. Srinivasan.

Objective:

• To develop an inventory of land-based point and nonpoint pollution sources for the Gulf of Maine regional watershed which will aid to establish a strategy to reduce pollution of the Gulf of Maine from significant sources.

Methodology:

Among the partners, the Pollution Sources Characterization Branch is responsible for building and refining the land-based pollution sources inventory. The Blackland Research Center does the analysis of nonpoint pollution sources and watershed modeling studies. The Coastal Programs Division provides guidance and insight on policy issues, and helps to coordinate the State and federal partners. The State coastal programs play a major role in coordinating the review of the inventory and explore the potential use of the information to support State program needs.

Phase I - Point Source Inventory:

The development of a point source inventory to assist in the reduction of impacts of point source pollution in the Gulf has been already completed. It includes background data and pollutant discharge estimates for 273 major and 1751 minor direct point sources discharging in the 25 major watersheds and 11 minor coastal drainage areas draining to the Gulf of Maine. Estimates of annual and seasonal discharges for the base year of 1991 are made for the following 15 parameters that are of concern because of their water quality and on human health: flow, biochemical oxygen demand, total suspended solids, nutrients - nitrogen and phosphorus, heavy metals - arsenic, cadmium, chromium, copper, iron, lead, merrcury, and zinc, oil and grease, and fecal coliform bacteria.

Monitoring data from Environmental Protection Agency's pollution monitoring program as reported in each facility's discharge monitoring report was used to make pollutant loading estimates. When this informaton was not available, permitted discharge limits set under the U.S. National Pollutant Discharge Elimination System were used. If monitoring and permitted pollutant limit data were unavailble, typical pollutant concentration values were used and assigned to an industrial facility or wastewater treatment plant. Information in the inventory can be aggregated by watershed, by both 8-digit U.S.G.S. hydrologic cataloging units and 11-digit subbasins that makeup the watersheds, or by county.

Phase II - Nonpoint Source Inventory:

The development of a nonpoint source inventory to assist in the reduction of the impacts of nonpoint sources of pollution in the Gulf is not yet complete. The hydrology of the U.S. portion of the Gulf of Maine region is being modeled using an integrated approach: (i) a hydrological model is being used to model the surface and subsurface water quantity, (ii) a Geographic Information System (GIS) is being used to collect, manage, analyze, and display the spatial and temporal inputs and outputs, and (iii) relational databases are being used to manage the non-spatial data and drive the model.

The system divided the U.S. portion of the Gulf of Maine region into 42 subbasins (polygons), and the model inputs were derived for each polygon to be simulated for a five year period (1989-1994). For all the subbasins, this project required information about historical weather, soil properties, topography, natural vegetation, cropped areas, and irrigation. The spatial databases were assembled at both 1:24,000 and 1:250,000 scales using a geographic information system environment called Geographical Resources Analysis Support System (GRASS).

A watershed-scale model called SWAT is used to estimate the nonpoint source discharges and route the loadings through each watershed to the estuary. For this project, SWAT has been updated to include improvements on urban runoff, snowmelt, and instream water quality.

Results:

Major results drawn from the analysis of point source inventory include:

• There are 273 major and 1751 minor facilities in the study area. Sixty-nine percent of these facilities are in the United States.

• In the U.S., there are 1069 active industrial facilities, 252 wastewater treatment plants, and 85 power plants; in Canada, there are 492 industrial facilites, 126 wastewater treatment plants, and 8 power plants.

• In the U.S., wastewater treatment plants account for over 50 percent of the total load discharged for all 15 pollutants, although industrial facilities are responsible for approximately 38 percent of the chromium discharges in the study area. In Canada, wastewater treatment plants are responsible for the greatest portion of the total pollutant loads for total nitrogen, total phosphorus, arsenic, cadmium, copper, iron, lead, mercury, oil and grease, and fecal coliform bacteria, while industries have higher discharges of process flow, biological oxygen demand, total suspended solids and zinc.

• U.S. facilities account for about 84 percent of the process flow discharged into the Gulf of Maine. The Massachusetts Bay watershed alone accounts for over 36 percent of this flow. Four watersheds account for over 78 percent of the total process flow in the study area. Wastewater treatment plants are the primary source of process flow for the Massachusetts Bay and Merrimack River watersheds, while industry is the major source for the Sheepscot Bay and Saint John River watersheds.