York Rivers Association

About Us
About the York River

In The NewsContact Us
Our Projects
Healthy rivers, healthy Gulf of Maine.   View of River


Our Projects > Studies and Information About York's Rivers, Maine > Water Quality


The water quality in the York River is generally quite good.  Water quality supports fishing and swimming, although sewage discharges prevent the harvesting of shellfish.  These uses are prevented when E. coli bacteria levels are too high.

Although bacterial pollution is often the type of pollution of greatest concern to people, aquatic life generally isn't terribly bothered by bacteria.  Fish and other aquatic life depend more on high levels of dissolved oxygen, appropriate temperatures, neutral pH (rather than acid rain), nutrients in the proper balance, and natural flows with seasonal variation.  Accordingly, a comprehensive water quality monitoring program looks at many other factors.

Probably the most intensive studies of the York River estuary has been by the Maine Department of Marine Resources and the York Conservation Commission.  Both groups have focused primarily on bacterial pollution (which results in the most direct threat to shellfishing). Both groups have also taken some other measurements, including temperature, dissolved oxygen, and salinity.  Although water quality does limit recreational shellfishing, steps are being taken to prevent point-source discharges of human sewage to the river.  Once these are fixed, a more intensive survey of non-point sources of bacterial pollution may be desirable, particularly if the river continues not to meet shellfishing water quality standards.

  • Although non-point source pollution is probably the greatest threat to the health of the York River, little upstream monitoring has been done to determine which areas are most threatened by non-point source pollution, particularly in the freshwater portions of the watershed.
  • No water quality monitoring has been done with the specific interest of categorizing the river for fish habitat.
  • No biomonitoring has been done in the York River (although some has been done for the sediments, see T1.)  Possible biomonitoring could include:
    • Tissue analysis of blue mussels for PCBs and dioxins.  Maine DEP has done these samples in other areas, and is likely interested in doing the tests on mussels from the York River. To encourage this, contact John Sowles, 207-287-6110.
    • Macroinvertebrate surveys. This method uses freshwater macroinvertebrates as indicators of water quality, and is gaining favor as a water quality monitoring method across the U.S.  Volunteer programs may involve local high school classes; the Maine DEP also uses this method, but has not sampled in the York River tributaries.
  • In order to reopen closed clam flats, a more intensive study of bacterial pollution may be useful, particularly once overboard sewage discharges have been corrected by local homeowners and businesses.  Once these problems are fixed, non-point source pollution will be the largest source of bacterial pollution.
  • It is not known what impact the interstate and associated roadways have on the York River.
  • ;
  • The existing water quality data is not in a single database or GIS system.  In order to track long-term trends, as well as possible gradual decline from non-point source pollution, it would be desirable to put all data in one place for analysis.  This would also facilitate presentation of any sub-standard areas to DEP for inclusion in the Impaired Waters list.

Specific Studies

Q1. Clean Water Act - Impaired Waters List (303d List) Maine DEP, 1998.

All water bodies have a classification under the Federal Clean Water Act, based on classification standards established at the state level. The states compile a list of waters that do not meet their standards; this is revised ever 2 years.

York River Water Quality Classifications:

  • Class A Ponds used for drinking water: Boulter Pond, Belle Marsh Reservoir.
  • Class B All other freshwater portions of the river.
  • Class SB (Saline B) Estuary portion of the river.

1998 List of Impaired Waters (303d List):

  • Smelt Brook - Class B.  Impaired due to low dissolved oxygen (DO) 2-3 ppm. Class B waters should have at least 7 ppm.  The low DO is because Belle Marsh Reservoir releases water from the bottom of the impoundment: water from the bottom of lakes is usually depleted of oxygen. This may affect the smelt run, and other fish/aquatic life, downstream.
  • York Harbor - Class SB.  Impaired due to bacterial contamination from human sewage, via the permitted overboard discharges.
  • Scituate Pond - Class B.  Impaired due to nutrients / algal blooms.  The source is unknown.
  • York Pond - Classified as "Threatened" due to expected land use changes in the watershed over the next 10 years, expect an increase in eutrophication from excess nutrients in rainwater runoff.

2000 Revisions to the List of Impaired Waters:
The next revision to the 303d list will be in April 2000. DEP does not anticipate having any new data for the York River. The York Rivers Association may wish to follow this process, and encourage DEP to add other impaired waters, or to encourage DEP to develop management plans to reduce pollution to the impaired bodies.

For a complete discussion of the Clean Water Act, the 303d List, and how Total Maximum Daily Loads (of pollution) regulations can be used to combat non-point source pollution, obtain a copy of River Network's excellent manual: The Clean Water Act, an Owner's Guide.

Contact: Maine's contact for the 303d list is Dave Courtemanch, DEP Augusta. 207-287-7789.

Q2. Sanitary Survey for York, Shellfish Growing Areas B & C. Maine Department of Marine Resources, Laura Livingston. April 1999.

This report is based on fecal coliform data collected from 1993-1998, and delineates open and closed shellfishing areas. Includes text of DMR regulations regarding shellfishing in York and maps of open and closed areas. Data includes raw data from 1993-98 for fecal coliforms/100 mL, shoreline survey narratives, and a map of potential pollution sources. Information about York Waste Water Treatment Plant.

Contact:  Laura Livingston. Maine Department of Marine Resources.

Q3. Dissolved Oxygen in Maine Estuaries and Embayments. Casco Bay Estuary Project, Wells National Estuarine Research Reserve, Maine DEP. 1996 Results.

A technical report, not written for the layperson. This study calculates the total volume of the estuaries/embayments, determines their flushing rates, and calculates ocean input compared to annual runoff from the watershed.  The report indicates that York Harbor takes about 17.5 hours to flush.

The study also measured water quality parameters.  Here is a summary of data from Table 1b (1996), which presents the average measurements for York Harbor.

    Salinity 27.6 ppt
    Temperature 19.1 degrees C
    Dissolved Inorganic Nitrogen 3.2 uM
    Ammonia (NH4) 2.44 uM
    Dissolved Organic Nitrogen 17.6 uM
    Total Nitrogen 24.3 uM

Dissolved oxygen was relatively low in the York Harbor, with a minimum DO of 5.28 mg/l (67.9% of saturation), and a mean of 6.83 mg/l (86.8% of saturation).

Q4. Volunteer Monitoring Program, York Conservation Commission (with assistance from the State Coastal Program). 1994-1998.

Volunteer-collected data, working with high school, over 5 years at a total of 19 sites (not all sites were sampled all years). Total number of samples at each site ranged from 52 to 2. Most sample sites were along the Little River, which runs through the more populated section of York.  Three sites were on the York River: Upper Barrels Mill Pond, Lower Barrels Mill Pond and Wiggly Bridge.

Link: York Conservation Commission Monitoring Home Page. (If that link has expired, you can find the new page by going to the York Conservation Commission link from Town Government page.)

Q5. Monitoring for Boulter Pond: Maine DEP. 1977.

This one-time monitoring for Boulter Pond consisted entirely of using a secchi disk to measure water clarity.  In 1977, the water clarity was 3 meters.  This report is not very useful, because not only are there no other data to compare, but it also doesn't indicate where on the pond the measurement was taken.  Maine's DEP program has not done any other monitoring in the watershed that was on file.

Contact: This information was obtained from Susan Davies, Maine DEP Biomonitoring. 207-287-7778.

Q6.  York River Estuary Monitoring.  Unknown.  1992.

Collected data from 7 sites on the York River, ranging from freshwater to the estuary, and measured dissolved oxygen, temperature and salinity, both early in the morning and in the afternoon in late July 1992.

(What is the source of this data?  It was originally filed along with the Dissolved Oxygen study, Q3 above.  Are there data from other monitoring dates at the same sites?)


Q7.  Non-Point Outreach for Municipal Officials (NEMO).  University of Connecticut Cooperative Extension Service.

This outreach program was first developed in the early 1990s, and has been duplicated across the country.  It consists of a traveling slideshow presentation for municipal officials.  The presentation uses GIS maps, build-out analyses, and predictors of water quality to show the impact of non-point source pollution on watersheds.  The Coastal Mosaic project is a NEMO-like project.  However, the original is worth taking a look at!

Their entire slideshow is available on the web, or you can download a power-point presentation.

Links:  Non-Point Outreach for Municipal Officials home page.

Q8.  Non-point Source Fact Sheets.  Published by a collaboration of agencies, including Cumberland County Soil & Water Conservation District.

This series of photocopied fact sheets are quite lacking in visual design appeal, but provide basic technical information about watersheds and prevention of non-point source pollution.

Q9. A Developer's Guide to the Maine Stormwater Management Law. Maine Department of Environmental Protection, March 1999.

According to the State Coastal Program, the York River is a priority watershed for non-point source pollution reduction.

However, DEP does not include it as a sensitive watershed for the Stormwater Management Law. Sensitive or threatened watersheds require additional stormwater permits for projects with 20,000 ft. or more of impervious surface.  The York River watershed has not been included because it is not near the threshold for a percent of impervious surface that would cause water quality to be threatened.

The town could enact stormwater quality standards that are stricter than what DEP requires; it might be possible for the towns of the York River Watershed to proactively require permits according to the standard DEP rule for priority watersheds.

Contact:  Maine DEP, Jeff Dennis.  207-287-7847.

Q10.  Maine DEP Watershed Planning / Non-Point Source Information.

Maine DEP provides a wealth of information about watershed planning and preventing non-point source pollution.

Contact:  Look at their web site, or call Norman Marcotte 207-287-7727.

Q11.  EPA Volunteer Water Quality Monitoring Manual.

This EPA manual was developed along with River Watch Network, a national volunteer monitoring assistance organization.  It includes sample Quality Assurance Plans, as well as information on why monitor most common parameters that are part of a volunteer water quality monitoring program.

Link:  EPA Volunteer Stream Monitoring - see especially Chapter 5.


Continue to Pollution Studies: Toxics & Sediments.

Return to the Index.

Home Page | About Us | About York's Rivers | Projects | Resources | In the News | Contact Us

© 2002-2007 The York Rivers Association.
Generous donations from the Old York Garden Club help to make this website possible.