Overview

WHY WE NEED CLEAN WATER

Clean water is central to the health of the Cape’s natural ecosystems. Our coastal waters, estuaries and embayments support valuable shellfish such as oysters and clams, as well as important finfish such as winter flounder and striped bass. Waterbirds, migrating waterfowl, raptors and wildlife feed on fish, shellfish and aquatic plants. Freshwater ponds and streams support numerous fish and wildlife species, including important diadromous species such as river herring and American eels, which live in both fresh water and the ocean. The Cape’s ecosystems and food webs depend upon clean water. 

Clean water is also important for our economy. The Cape’s economy is a “blue economy” where our residents, visitors and businesses rely upon clean water and healthy natural resources. The economic benefits of clean water and healthy ecosystems are demonstrated by the fact that coastal tourism and commercial and recreational fishing and shellfishing and their supporting industries bring in more than $1 billion to the local economy. For example, in 2018 tourists visiting Cape Cod spent $1.32 billion that supported 10,844 tourism-related jobs and $357.7 million in wages, and generated $133 million in state and local taxes (Cape Cod Chamber of Commerce).

Commercial and recreational fishing and shellfishing also bring in additional millions of dollars each year. For example, from 2000 – 2004, the average annual value of commercial and recreational shellfishing was $11.4 million. In 2009 alone the value of commercial fishing was $19 million, while the value of commercial fishing for species that eat river herring was over $37 million (NRCS, Cape Cod Water Resources Restoration Project: Why It Matters to Massachusetts Economy). These numbers do not include water-focused organizations such as oceanographic institutions and businesses, non-governmental organizations, educational institutions and laboratories that employ people and provide services and products.

Finally, clean drinking water is critically important for our health. The water we drink comes from Cape Cod’s sole-source aquifer, a vast underground natural reservoir of groundwater. Federal, state and local laws are designed to protect a sole-source aquifer from pollution. However, as we discuss below, our groundwater, ponds, lakes, estuaries and embayments are all interconnected.

WATERS OF THE CAPE

Cape Cod enjoys a wealth of water resources. These include salt water and freshwater resources. Each major resource is summarized below. More information can be obtained at the Cape Cod Commission’s website on water resources.

Coastal waters (saltwater) surround most of the Cape, creating over 559 miles of coastline bordering the Atlantic Ocean, Nantucket Sound, Vineyard Sound, Buzzards Bay and Cape Cod Bay. This long coastline contains 53 distinct saltwater embayments, places where there is a recess or indentation in the coastline that forms a bay bordering the ocean. Estuaries are places where rivers meet the sea. Estuaries typically contain a range of wetlands including freshwater, brackish and tidal wetlands (aka salt marshes) and tidal channels. On Cape Cod, rivers, streams and groundwater flow into estuaries and embayments that border the ocean.

Freshwater ponds and lakes: Few people know that the Cape is the land of (nearly) a thousand lakes. At least 996 freshwater ponds and lakes cover nearly 11,000 acres, and individual ponds and lakes range in area from less than one acre to 735 acres and include 166 “great ponds” of 10 acres or greater in size. Because the Cape’s ponds and lakes are fed by groundwater, they are often referred to as “windows on our aquifer.” The sandy soils of the Cape allow groundwater to flow into and out of ponds. For this reason, pollution of ponds will likely also pollute groundwater, and vice versa.

Groundwater: Groundwater is the lifeblood of the Cape. Rain and melting snow quickly soak into our sandy soils where it collects to form a huge underground reservoir of groundwater that lies beneath most of the Cape. Water seeks the lowest elevation, so groundwater continues to move, seeking sea level, flowing into and out of ponds, feeding streams and flowing towards the coast, finding sea level when it enters our estuaries and embayments.

Groundwater is also the sole source of our drinking water. In 1982, the U.S. Environmental Protection Agency designated Cape Cod’s groundwater as a sole-source aquifer for drinking water under the federal Clean Water Act and Safe Drinking Water Act. All of the Cape’s drinking water comes from this sole-source aquifer, which is protected by local, regional, state and federal regulations . Nearly all of the Cape’s public water supplies are from groundwater wells, with one exception being Long Pond in Falmouth, which is groundwater-fed.

Watersheds connect our waters: Nearly all of the Cape’s waters are connected by watersheds that collect water and discharge it into the ocean. Watersheds are the land areas that collect rain and snow, which drains into ponds, lakes, streams and groundwater, which in turn discharge into estuaries, embayments and the ocean. Cape Cod has a total of 101 watersheds that discharge to the ocean. Of these, 53 discharge to embayments, which are susceptible to nitrogen pollution, and the remainder discharge directly to the ocean. Through the Section 208 Water Quality Management Plan for Cape Cod, the Cape Cod Commission has created a regional blueprint for protecting and improving water quality and tracks progress in implementation.

Hydrological cycle: The Cape receives about 45 inches per year of rain and melting snow. About 60 percent of this precipitation soaks into the ground to replenish groundwater. Most of the remaining 40 percent evaporates into the atmosphere where it provides moisture for storms that provide rain and snow (see below). A small amount becomes stormwater runoff. Due to the sandy soils, this runoff generally soaks into the sand and replenishes the aquifer. However, when runoff flows from roads, parking areas and fertilized lawns directly into wetlands, ponds or the ocean, pollutants from these developed areas can enter the water. Stormwater pollutants can include fertilizers, bacteria, soil particles, metals and de-icing compounds.

Groundwater is used up (depleted) when we withdraw it for drinking water and when it flows into ponds, streams, embayments and into the ocean. Ponds, streams and wetlands lose water due to evaporation, and trees also “breathe” water back into the air in a process called “evapotranspiration.” This evaporated water is not truly “lost.” Instead, it is critically important for feeding water back into the atmosphere to grow storms that produce rain and snow. Groundwater is replenished by rain and melting snow, which soak into the ground, beginning the hydrological cycle all over again.

WATER POLLUTION

Most of the Cape’s coastal embayments and many freshwater ponds and lakes are suffering from water pollution, based on years of studies and reports on water quality and water pollution. These studies and reports indicate that the Cape’s waters suffer from pollution due to the following pollutants and pollution sources.

Nutrient pollution: Excess nutrients (nitrogen in coastal waters and phosphorus in fresh water) have caused severe eutrophication and severe ecological damage. Eutrophication refers to the harmful effects of excess nutrients on an aquatic ecosystem, resulting in increased growth of phytoplankton and depletion of oxygen. Excess nutrients in water stimulates the growth of phytoplankton (microscopic algae), which depletes the water of oxygen. Oxygen depletion leads to fish kills and impacts on shellfish and other aquatic life. Excess phytoplankton also causes water to become cloudy, reducing the amount of light in the water column, which impacts the growth of other beneficial aquatic plants such as eelgrass. When algae die, their remains settle to the bottom and decompose, causing more oxygen depletion and releasing nutrients back into the water, feeding the nutrient cycle. Also, the buildup of decaying organic matter on the bottom of ponds, lakes and embayments often results in thick muck that is unhealthy for shellfish, fish and other aquatic organisms.

Many of the Cape’s estuaries and embayments are suffering from eutrophication caused by excess nitrogen, as demonstrated by the Massachusetts Estuaries Project and by the Section 208 Water Quality Management Plan for Cape Cod.

Ponds and lakes are also suffering from eutrophication caused by excess phosphorus (Cape Cod Commission, Ponds and Lakes).

On Cape Cod, excess nutrients originate largely from human sources and activities. Excess nitrogen comes from poorly treated wastewater (e.g., Title 5 septic systems) as well as fertilizers used on lawns, gardens, golf courses and farms. Some nitrogen also falls out from the atmosphere in precipitation, and this atmospheric nitrogen largely originates from burning fossil fuels. Excess phosphorus comes from septic systems that discharge phosphorus into groundwater that enters ponds and lakes, as well as fertilizers used on lawns, gardens, golf courses and farms that is carried into ponds and lakes in stormwater runoff.

Harmful bacteria include bacteria that originate from fecal wastes (humans and/or animals). Examples of fecal bacteria are Escherichia coli (E. coli) and enteric bacteria. Fecal bacteria can cause illness in both humans and animals. On Cape Cod, most fecal bacteria contamination originates from domestic animals and wildlife. Failed septic systems (including flooded septic systems) are another source of bacteria. Bacteria are carried into water by stormwater runoff. State and federal water quality standards limit the amounts of fecal bacteria that can be present in waters where swimming and shellfishing are conducted. Swimming beach water quality is monitored by Barnstable County. The Massachusetts Division of Marine Fisheries monitors water quality in shellfish beds and limits shellfishing to waters that meet a stringent water quality standard for fecal bacteria.

Harmful algal and cyanobacteria blooms include toxic red tides in coastal waters and toxic cyanobacteria blooms in freshwater ponds and lakes. Red tide is the common name for several species of phytoplankton, including toxic dinoflagellates. Shellfish that ingest such toxic phytoplankton become toxic themselves, posing a threat to humans who eat contaminated shellfish and impacting the shellfishing industry. In fresh water, toxic cyanobacteria thrive in nutrient-rich and warm waters. APCC’s Cyanobacteria Monitoring Program has documented cyanobacteria blooms in dozens of ponds throughout the Cape, and we anticipate this will be an increasing problem as nutrient pollution continues and the climate warms. This year, APCC incorporated cyanobacteria monitoring data from 2019 into our grading system for freshwater ponds as another indicator of nutrient pollution.

Mercury pollution occurs in waters throughout the Northeast. On Cape Cod, the Massachusetts Department of Public Health has listed at least 24 ponds and lakes where there are fish consumption advisories that warn people (pregnant mothers) to limit or avoid eating fish from that lake due to mercury pollution. Mercury pollution is caused by fallout of mercury from the atmosphere, which originates from combustion of coal in coal-burning fuel plants. Incineration of medical wastes and municipal wastes also contributes mercury to the atmosphere.

Emerging contaminants and pharmaceutical compounds have been found in groundwater near septic systems and in coastal waters of the Cape. This group of pollutants contains a wide variety of compounds, including endocrine-disrupting compounds, pharmaceutical drugs (including antibiotics), insect repellant, flame retardant, fluorinated compounds and PFAS (per- and polyfluoroacetate substances). The Silent Spring Institute has been monitoring the Cape’s waters emerging contaminants. The Center for Coastal Studies and Silent Spring Institute also found pharmaceutical compounds in Cape Cod Bay and in groundwater near septic systems, pointing to septic systems as the source of these pharmaceutical compounds.

PFAS (per- and polyfluoroacetate substances) are manmade chemicals used widely in diverse items (e.g., fireproof clothing, non-stick pans, stain-and-waterproof fabrics, fire-fighting foam, dental floss, cleaning products, paints, electronics manufacturing and other industries and household products). PFAS are long-lasting compounds that have been found worldwide in humans, wildlife, water, soil and the air. They have been linked to human health impacts such as developmental disorders, immune system disorders, thyroid hormone disruption and cancer. Information on PFAS can be found on the websites of the EPA and the Commonwealth of Massachusetts.

 

Aeriel photo of Cape Cod pond

photo by Steven Koppel

HOW WE GRADED WATER QUALITY

To help people understand where water quality is acceptable vs. unacceptable, APCC has created this State of the Waters: Cape Cod project and website to collect existing information on water quality and translate it into easily understood terms by grading water quality. This website is a key means of collecting and distributing information to the public. In doing so, we hope to guide public policy and investment in restoration efforts.

 

Using existing data, APCC graded the following water resources:

  • Coastal waters in embayments and estuaries;

  • Freshwater ponds and lakes; and

  • Public water supplies for drinking water (i.e., drinking water after it is treated by the public water supplier and before it is distributed to consumers).

APCC used three grading systems, one system for grading coastal waters, a second system for grading ponds and lakes, and a third system for grading drinking water. Each of the grading systems scores water quality parameters. The scores were then translated into grades. APCC chose grading systems that meet the following criteria:

  • Are scientifically sound;

  • Have been used before to evaluate water quality;

  • Use key water quality parameters to evaluate water quality problems;

  • Are easily understood and can be replicated by others (e.g., it does not require complex methods, modeling or software); and

  • Evaluates the most pressing water quality problems.

The grading systems are explained below.

Grading coastal waters: Buzzards Bay Eutrophic Index

APCC chose an existing method of grading the severity of nitrogen pollution of coastal waters. The method is called the Buzzards Bay Eutrophic Index (aka “Bay Health Index”), developed in 1992 by the Buzzards Bay National Estuary Program. The Eutrophic Index was based on an earlier method developed by Hillsborough County, Florida, to evaluate coastal water quality.

The Buzzards Bay Eutrophic Index was developed to help the Buzzards Bay Coalition (BBC) evaluate citizen water quality monitoring data for Buzzards Bay embayments and to help rank each embayment with respect to its relative health for the purpose of prioritizing remedial management measures (i.e., Bay Health ). The goal was to evaluate nitrogen loading inputs and to provide accurate and reliable water quality data for most of the major embayments around Buzzards Bay to assist environmental managers to:

Embayments and estuaries often contain aquatic habitats that range from freshwater to brackish to salt marsh to open water bays bordering the ocean. For coastal embayments that contain salt marshes, the Buzzards Bay Coalition developed a variation of their scoring system. APCC’s scoring of salt marsh systems follows the approach used by the Buzzards Bay Coalition with additional input from salt marsh experts.

  • Establish baseline water quality;

  • Characterize and identify sources of pollution;

  • Document long-term environmental trends in water quality;

  • Evaluate the relative success of cleanup efforts;

  • Facilitate implementation of management efforts in the CCMP; and

  • Evaluate the appropriateness of the Buzzards Bay Project’s recommended nitrogen limits.

Since then, the Eutrophic Index has also been used by the Center for Coastal Studies, the Pleasant Bay Alliance, and the town of Chatham to evaluate nitrogen pollution in Buzzards Bay, Cape Cod Bay and coastal waters around the Cape, Pleasant Bay, and Chatham, and is considered by practitioners to be a well-tested method.

The Eutrophic Index scores parameters that measure the degree of eutrophication: dissolved oxygen saturation, water clarity (measured using either Secchi disk or a turbidity meter), chlorophyll, dissolved inorganic nitrogen (DIN), and total organic nitrogen (TON). Water quality data for these parameters is used to calculate a numerical score that indicates the degree of eutrophication. To translate scores into an assessment of water quality, the BBC uses three categories to “grade” scores: scores of 65 to 100 indicate Good water quality; scores between 35 and 65 indicated Fair water quality; and scores below 35 indicate Poor water quality.

Following the BBC’s method, APCC calculated numerical Eutrophic Index scores for water quality from stations in coastal embayments and coastal waters around Cape Cod. However, APCC “graded” the numerical scores in a manner that differs from the BBC. APCC assigned scores to two categories based on whether they indicate acceptable water quality or unacceptable water quality. The two grading categories were chosen to indicate the type of action needed to protect or restore water quality:

Scores greater than 65 are graded as: “Acceptable: requires ongoing protection.”

Scores of 65 and below are graded as: “Unacceptable: requires immediate restoration.”

Waters that are graded as “Acceptable: requires ongoing protection” are waters that are healthy and free of excess nutrients. These waters need ongoing protection to remain healthy and free of pollution.

Waters that are graded as “Unacceptable: requires immediate restoration” are waters that are suffering from excess nutrients. These waters need immediate restoration in order to improve water quality.

APCC also took the additional step of identifying embayments where at least one monitoring station had Unacceptable water quality and graded these embayments as “Unacceptable: requires immediate restoration.” Embayments where all monitoring stations had Acceptable water quality were graded as “Acceptable: requires ongoing protection.” This approach provides a clear summary of which embayments have portions with poor water quality that requires restoration vs. embayments with good water quality that require protection.

Grading ponds and lakes: Method 1: Carlson Trophic Index

To grade freshwater ponds and lakes, APCC uses a scoring method that evaluates the trophic state of the water body in terms of three important water quality parameters: total phosphorus, chlorophyll and water transparency. The Carlson Trophic Index was developed in 1996 to assess the trophic state of a freshwater pond or lake, where trophic state refers to the ecological response (algal biomass) to nutrients (Carlson, 1977). Since then it has been widely used for evaluating freshwater ponds and lakes.

Using the Carlson Trophic Index, a pond with high nutrient concentrations (eutrophic to hypereutrophic) would be characterized by high concentrations of algae, algal scums, poor water clarity due to dense algae and low to no dissolved oxygen. A eutrophic to hypereutrophic pond would have scores from 50 to 100. At the opposite end of the spectrum, a pond with low nutrient concentrations (oligotrophic) would be characterized by clear well-oxygenated water, healthy aquatic plants and little to no algal growth. An oligotrophic pond would have scores from 0 to 40. A pond with intermediate nutrient concentrations (mesotrophic) would be characterized by moderately clear water, intermediate amounts of aquatic plants and algae, and low dissolved oxygen during the summer. A mesotrophic pond would have scores from 40 to 50. The Carlson Trophic Index is analogous to the Buzzards Bay Eutrophic Index in that it can be used to evaluate the degree of eutrophication in fresh water.

APCC adopted a grading system that assigns the following grades to Carlson Trophic Index scores:

Scores of less than 50 are graded as: “Acceptable: requires ongoing protection.”

Scores of 50 and above are graded as: “Unacceptable: requires immediate restoration.”

Waters that are graded as “Acceptable: requires ongoing protection” are waters that are healthy and free of excess nutrients. These waters need ongoing protection to remain healthy and free of pollution.

Waters that are graded as “Unacceptable: requires immediate restoration” are waters that are suffering from excess nutrients. These waters need immediate restoration in order to improve water quality.

In 2020, APCC adopted new criteria for water quality data to be used for grading ponds using the Carlson Trophic Index. These are described below.

Grading ponds and lakes: Method 2: using cyanobacteria monitoring data

Many pond water quality data for Cape Cod ponds are older, i.e., at least five years old or more. Using older data to grade ponds would cause grades to reflect conditions that existed at the time when water samples were collected and analyzed. Conditions in ponds may have changed since these older data were collected. APCC tested screening out pond data older than 2015 and ponds where there was less than three years of data. Using these more stringent data quality requirements for grading resulted in only 29 ponds having sufficient data to enable grading using the Carlson Trophic Index. This points out the severe shortage of newer Cape-wide pond monitoring data to inform pond management and protection measures.

Beginning this year, to help fill the gap in freshwater pond data, APCC utilized cyanobacteria monitoring data to provide an additional measure of pond health. Since 2018, APCC has been monitoring cyanobacteria and cyanobacteria blooms in dozens of freshwater ponds on Cape Cod. Cyanobacteria blooms occur when there are sufficient nutrients to stimulate growth of these photosynthetic bacteria. Warmth and sunlight are other factors that stimulate cyanobacteria growth, but in the absence of nutrients or when nutrient concentrations are very low, cyanobacteria growth is minimal. Cyanobacteria blooms therefore represent another way to describe nutrient enrichment in freshwater ponds.

APCC’s Cyanobacteria Monitoring Program uses an EPA-approved protocol developed by the Cyanobacteria Monitoring Collaborative. The protocol utilizes a combination of field observations, microscopy and fluorometry to analyze samples from freshwater lakes and ponds for cyanobacteria. The data collected includes photographs and field observations, digital microscopy to identify composition (type of cyanobacteria present) and dominance, and concentrations of phycocyanin and chlorophyll pigments indicative of the amounts of cyanobacteria vs. general algae and phytoplankton, respectively. By monitoring biweekly from June to October, APCC tracks changes in cyanobacterial composition, dominance and abundance. At this sampling frequency, APCC is often able to forecast when cyanobacteria blooms may be forming or when toxin concentrations may be approaching harmful levels. These signs instruct APCC to increase the frequency of testing and to inform town officials to be aware of potential threats and to plan for proactive management actions to protect public safety.

In contrast to traditional cyanobacteria testing involving cell counts, APCC’s method is less costly, offers a faster turn-around time for results and is often able to predict cyanobacteria bloom formation. Additionally, numerous other points of data collected support research efforts that will expand our understanding about the health of the ponds.

To interpret cyanobacteria monitoring data, APCC developed a new cyanobacteria grading system utilizing “Low,” “Moderate” and “High” tiers (where High represents levels where pets and humans are advised to avoid contact with pond water). The new cyanobacteria grading system was applied to grade ponds monitored in 2019 by APCC and by town officials. If a town posted a cyanobacteria advisory in 2019, that pond was placed in the same category as those ponds in APCC’s “High” tier. Similarly, ponds monitored by town officials that never required the posting of an advisory for cyanobacteria in 2019 were placed in the same category as those that only reached the “Low” or “Moderate” tier in APCC’s Cyanobacteria Monitoring Program. Learn more about APCC’s Cyanobacteria Monitoring Program.

Updated Pond Grading System

Beginning this year (2020), APCC’s pond grading system was revised to include both Carlson Trophic Index grades and cyanobacteria data, as described below:

  1. Carlson Trophic Index scores and grades for ponds were calculated only for ponds where more recent water quality data from 2015 on was available, and where at least three years of data were available.
  2. Cyanobacteria monitoring data from 2019 were used to grade ponds using APCC’s tiered cyanobacteria system described above:
    1. Ponds with “High” cyanobacteria levels were graded as “Unacceptable: requires immediate restoration”;
    2. Ponds with “Low” or “Moderate” cyanobacteria levels were graded as “Acceptable: requires ongoing protection.”
  3. If a pond had both Carlson Trophic Index grades and Cyanobacteria grades:
    1. The pond was graded as “Acceptable: requires ongoing protection” only if both grades were Acceptable;
    2. Conversely, a pond was graded as “Unacceptable: requires immediate restoration” if at least one of the grades was Unacceptable.
  4. If a pond had only one grade (i.e., Carlson Trophic Index grade or Cyanobacteria grade), that grade was used as the overall pond grade.

Grading public water supplies of drinking water

The grading system for drinking water is based on a modification of a method developed by the Natural Resources Defense Council (NRDC) to grade drinking water. The NRDC grading system evaluates three areas of drinking water: water quality and compliance, source water protection, and right-to-know compliance. APCC chose to evaluate water quality and compliance of public water supplies after treatment and before distribution to consumers, the so-called “finished water.” This represents the underlying quality of the public water supply before it is distributed to customers, not the quality of the water as it comes out of your tap, which can be affected by pipes and plumbing in the distribution system and in your homes and businesses. APCC chose to evaluate public water supplies in this manner because underlying water quality represents the first line of defense in ensuring safe drinking water supplies and because many water protection measures are aimed at protecting source water quality.

To grade public water supplies, APCC used publicly available Consumer Confidence Reports for 2019 to determine if water quality met existing state and federal drinking water standards (i.e., Maximum Contaminant Levels, or MCLs). If a public water supply met all existing state and federal drinking water standards, it was graded as “Excellent” if not, it was graded as “Poor.”

SOURCES OF WATER QUALITY DATA

Cape Cod is fortunate to have many environmental organizations and agencies that have monitored water quality for many years. Over the years, hundreds of citizen scientists, local, state and federal government agencies, scientists, environmental organizations, consulting firms, and APCC interns and volunteers have collected water samples for different water quality monitoring programs. With the assistance of our Advisory Committee and partners, our sources of water quality data include the following:

Regional data (i.e., data collected from multiple embayments or a large area of the Cape):

  • Association to Preserve Cape Cod: cyanobacteria monitoring data from ponds located in the Upper Cape, Mid-Cape, Outer Cape and Lower Cape;

  • Buzzards Bay Coalition: Eutrophic Index scores for Buzzards Bay coastal stations;

  • Center for Coastal Studies: coastal water quality data collected from stations in Cape Cod Bay, Nantucket Sound and Vineyard Sound;

  • Cape Cod Commission: coastal and pond water quality data collected by and for the Cape Cod Regional Water Quality Database, a project to collect and make publicly available all water quality monitoring data for the Cape. The project is funded by the EPA Southeast New England Coastal Watershed Restoration Program (EPA SNEP);

  • Cape Cod Commission and University of Massachusetts at Dartmouth, School of Marine and Atmospheric Science and Technology (SMAST): Pond and Lake Stewards (PALS) data for pond water quality (note: most of the pond data provided by towns and organizations listed below was provided by PALS and SMAST for the towns and organizations);

Municipal and local watershed data:

  • Barnstable Clean Water Coalition: coastal water quality data and pond water quality data for the Three Bays watershed;

  • Town of Barnstable: coastal water quality data and cyanobacteria data;

  • Town of Chatham: coastal water quality data and Eutrophic Index scores for Chatham coastal stations;

  • Town of Dennis: pond water quality data for ponds;

  • Town of Eastham: coastal and pond water quality data;

  • Town of Falmouth: pond water quality data;

  • Town of Harwich: coastal and pond water quality data;

  • Town of Mashpee: pond water quality data;

  • Town of Orleans: coastal and pond water quality data;

  • Town of Sandwich: pond water quality data;

  • Pleasant Bay Alliance: Eutrophic Index scores for Pleasant Bay coastal stations; and

  • Waquoit Bay National Estuarine Research Reserve (WBNERR): coastal water quality data for Waquoit Bay.

Types of water quality data are summarized below. Data are also posted on this State of the Waters: Cape Cod website under Resources.

Water quality data for coastal embayments: For the 2020 report, APCC collected the most recent and available coastal water quality data from the data sources listed above. For most coastal stations and embayments, the most recent data available were for 2019; the only exceptions were Sesuit Harbor and Pleasant Bay, where the most recent data available were from 2018.

Water quality data for ponds and lakes: Since 2000, the Cape Cod Pond and Lake Stewardship program (PALS) has worked with volunteers and organizations who monitor many ponds across the Cape. The PALS program was developed by the Cape Cod Commission, APCC and SMAST, in coordination with organizations and towns that monitor water quality on an annual snapshot basis. Other pond associations and organizations have gathered a considerable amount of data with their member volunteers. For the 2020 report, APCC collected pond water quality data from the sources listed above.

Cyanobacteria data for ponds and lakes: Cyanobacteria monitoring data were provided by APCC’s Cyanobacteria Monitoring Program and by the town of Barnstable, which conducts a similar cyanobacteria monitoring program for ponds in Barnstable.

Water quality data for public water supplies: For the 2020 report, APCC collected each town’s public-right-to-know reports, also known as the Consumer Confidence Reports (CCRs) for drinking water. These are posted on town websites. CCRs were used to grade water quality and compliance with existing drinking water regulations. CCRs are posted on each town’s website and links to the CCRs are provided in our Public Water Supplies grading sheet under Data.

RESULTS

Our scores and grades for coastal embayments and stations, ponds and lakes, and public water supplies are provided as maps ( Embayment Status , Embayment Station Status, Pond Status and Public Water Supply Status) and as read-only spreadsheets (e.g., The Data, under Resources). Our findings are provided below, first as a Summary and then as Detailed Findings.

Summary

For coastal embayments, the number (38) and percentage (79%) of Unacceptable embayments increased from last year. Embayments newly graded as Unacceptable this year face Vineyard Sound, Nantucket Sound, Cape Cod Bay and Buzzards Bay. The number (10) and percentage (21%) of Acceptable embayments decreased from last year.

For coastal embayment stations, the number (106) and percentage (70%) of Unacceptable embayment stations increased from last year. The number (46) and percentage (30%) of Acceptable embayment stations decreased from last year.

For ponds, the percentage (42%) of Unacceptable ponds increased from 39% in 2019. The number (54) and percentage (58%) of ponds that are Acceptable decreased from 2019, when 91, or 61%, of ponds were Acceptable.

Ponds this year were graded using a combination of Carlson Trophic Index grades based on water quality data, in addition to cyanobacteria grades based on cyanobacteria monitoring data from 2019 that utilizes APCC’s monitoring tiers of High (Unacceptable), Moderate and Low (Acceptable). Carlson Trophic Index grades were based on new, more stringent criteria for utilizing pond water quality data; i.e., data sets utilized must include at least three years of data collected no earlier than 2015. Only 29 ponds met these criteria. The Cape has 996 freshwater ponds. The fact that only 29 ponds have sufficient newer data represents a huge data gap that needs to be addressed if ponds are to be restored and protected, based on data reflecting current and recent conditions. Cyanobacteria grades were added to provide another measure of nutrient enrichment and to address a huge gap in pond water quality data.

Ponds continue to show the impacts of nutrient loading, whether they are graded using the Carlson Trophic Index or cyanobacteria.

For public water supplies, all public water supplies on the Cape continued to have Excellent water quality based on meeting existing drinking water regulations. APCC is monitoring the implementation of recently finalized regulations for PFAS and will apply these to public water supplies when regulations go into effect in 2021.

Detailed Findings

In 2019, APCC presented results of the first year of the State of the Waters: Cape Cod, an assessment of water quality in coastal embayments, ponds and public water supplies. The 2019 results were based on water quality data available through 2018. This year, APCC updated water quality grades using water quality data available through 2019. The embayment data used in our 2020 update includes data from 2019, with the exception of Pleasant Bay and Sesuit Harbor in Dennis, where the latest data available were from 2018. Ponds were graded using water quality data from no earlier than 2015 and included for the first time the results of APCC’s cyanobacteria monitoring. Results are described below.

Embayments

The number of embayments assessed as having Unacceptable water quality increased in 2020. Of the embayments graded, 79%, or 38 of 48, were Unacceptable, up from 68%, or 32 of 47 in 2019. Meanwhile, in 2020 the number of Acceptable embayments decreased. In 2019, the number of embayments graded as Acceptable was 15, or 32% of graded embayments, while in 2020 the number of Acceptable embayments decreased to 10, or 21% of graded embayments (Table 1).

The increase in Unacceptable embayments is due to five embayments facing Buzzards Bay, Cape Cod Bay and Nantucket Sound changing from Acceptable in 2019 to Unacceptable in 2020, and one embayment facing Vineyard Sound that had no data in 2019 being graded as Unacceptable in 2020 (Table 2).

The results show that more coastal embayments are being impacted by nutrients. There was no embayment that showed an improvement from Unacceptable to Acceptable.

Table 1. Grades for Coastal Embayments, 2019 and 2020 State of the Waters: Cape Cod.

  2019 SOTW   2020 SOTW    
  Number Percentage Number Percent % Change
Embayments graded

47

48

Unacceptable

32 *

68%

38

79%

Increased by 6

Acceptable

15

32%

10

21%

Decreased by 5

No data (not graded)

5

4

Decreased by 1 (1 became Unacceptable)

* Note: In 2019, SOTW Rushy Marsh Pond (U) was included and the number of Unacceptable was 33. In 2020, it was dropped because it is a salt pond, not an embayment, thus for this comparison it was also dropped from 2019. This reduces the number of Unacceptable embayments in 2019 to 32 and changes the percentages of U and A, as well as the total number of embayments graded in 2019).

Table 2. Number of Embayment Grades by Water Body, 2020 State of the Waters: Cape Cod.

Embayment Grades Nantucket Sound, Vineyard Sound, Pleasant Bay Buzzards Bay Cape Cod Bay Total number
Unacceptable 23 9 6 38
Acceptable 0 3 7 10
No data 1 1 2 4

Embayment stations

Of the 152 embayment stations graded in 2020, 106, or 70%, had Unacceptable water quality, while 46, or 30%, had Acceptable water quality. In 2019, a total of 152 embayment stations were graded and 98 stations, or 64%, had Unacceptable water quality and 54 stations, or 36%, had Acceptable water quality. The 2020 grades show an increase in the number of Unacceptable embayment stations (Table 3).

Table 3. Grades for Coastal Embayment Stations, 2019 and 2020 State of the Waters: Cape Cod.

  2019 SOTW   2020 SOTW  
  Number Percentage Number Percentage
Embayment stations graded 152   152  
Unacceptable 98 64% 106 70%
Acceptable 54 36% 46 30%

Ponds

The percentage of ponds assessed as having Unacceptable water quality increased in 2020. Of the ponds graded, 42%, or 39 of 93, were graded as Unacceptable, up from 39% in 2019. Meanwhile, the percentage of Acceptable ponds decreased to 58%, down from 61% in 2019. The results show that ponds continue to be impacted by nutrients (Table 4).

In addition, a comprehensive review and assessment of overall pond health is hampered by data quality issues. To grade water quality, APCC uses the Carlson Trophic Index, an index of water quality that describes the trophic status of a water body based on total phosphorus, chlorophyll and Secchi disk. Ponds that have scores placing them in the mesotrophic to eutrophic range were graded as Unacceptable, while ponds that have scores in the oligotrophic range were graded as Acceptable. Many pond data are older, i.e., at least five years old or more. Using older data to grade ponds would cause grades to reflect conditions that existed at the time when water samples were collected and analyzed. Conditions in ponds may have changed since these older data were collected. APCC screened out pond data older than 2015 and ponds with less than three years of data collected. Using these more stringent requirements for grading resulted in only 29 ponds having sufficient data to enable grading using the Carlson Trophic Index. This points out the severe shortage of more recent Cape-wide pond monitoring data to inform pond management and protection measures.

To help fill the gap in freshwater pond data, APCC utilized the results of our cyanobacteria monitoring program. Since 2018, APCC has been monitoring cyanobacteria and cyanobacteria blooms in dozens of freshwater ponds on Cape Cod. Cyanobacteria blooms occur when there are sufficient nutrients to stimulate growth of these photosynthetic bacteria. Warmth and sunlight are other factors that stimulate cyanobacteria growth, but in the absence of nutrients or when nutrient concentrations are very low, cyanobacteria growth is minimal. Cyanobacteria blooms therefore represent another way to describe nutrient enrichment in freshwater ponds.

APCC used our 2019 cyanobacteria monitoring data and cyanobacteria tiers of Low, Moderate and High (where High represents levels where pets and humans are advised to avoid contact with pond water) to grade ponds monitored in 2019. Cyanobacteria monitoring data collected by town officials in 2019 that were available to APCC were also included. If a town posted a cyanobacteria advisory in 2019, that pond was placed in the same category as those ponds that reached APCC’s High tier. Similarly, ponds monitored by town officials that never required the posting of an advisory for cyanobacteria in 2019 were placed in the same category as those that only reached the Low or Moderate tier in APCC’s Monitoring Program.

Table 4. Grades for Ponds, 2019 and 2020 State of the Waters: Cape Cod.

  2019 SOTW   2020 SOTW  
  Number Percentage Number Percentage
Total number of ponds on Cape Cod 996   996  
Ponds graded 149 15% of all ponds on Cape Cod 93 9% of all ponds on Cape Cod
Unacceptable 58 39% of graded ponds 39 42% of graded ponds
Acceptable 91 61% of graded ponds 54 58% of graded ponds
Ponds with CTI grades 149 100% of graded ponds 29 * 31% of graded ponds
Ponds with cyanobacteria grades NA NA 81 87% of graded ponds
Ponds with both CTI and cyanobacteria grades NA NA 17 18% of graded ponds

* Note: Carlson Trophic Index grades in 2020 were calculated only for ponds that met more stringent data quality criteria described in the Overview.

NA – Not applicable.

This report reflects revisions adopted in 2020 to the APCC pond grading system in the following ways:

  1. Carlson Trophic Index scores and grades for ponds were calculated only for ponds where more recent water quality data from 2015 on was available, and where at least three years of data were available.
  2. Cyanobacteria monitoring data from 2019 were used to grade ponds using APCC’s tiered cyanobacteria system described above:
    1. Ponds with “High” cyanobacteria levels were graded as “Unacceptable: requires immediate restoration”;
    2. Ponds with “Low” or “Moderate” cyanobacteria levels were graded as “Acceptable: requires ongoing protection.”
  3. If a pond had both Carlson Trophic Index grades and Cyanobacteria grades:
    1. The pond was graded as “Acceptable: requires ongoing protection” only if both grades were Acceptable;
    2. Conversely, a pond was graded as “Unacceptable: requires immediate restoration” if at least one of the grades was Unacceptable.
  4. If a pond had only one grade (i.e., Carlson Trophic Index grade or Cyanobacteria grade), that grade was used as the overall pond grade.

Only 29 ponds had sufficient water quality data to calculate Carlson Trophic Index grades based on our more stringent criteria for grading, while 81 ponds had cyanobacteria data that enabled grading. A total of 78 ponds either had no data, data that were too old, or insufficient data to calculate the Carlson Trophic Index grades. There were only 17 ponds with both Carlson Trophic Index grades and cyanobacteria grades.

For comparison, in 2019 APCC graded 149 ponds based on pond monitoring data available through the Pond and Lake Stewards (PALS) program. Of these 149 ponds, 91 were graded as Acceptable representing 61% of graded ponds, while 58 were graded as Unacceptable, representing 39% of graded ponds. Grading in 2019 did not incorporate our more stringent data quality criteria and thus a number of pond grades were based on older data.

Public Water Supplies

Public water supply grades for drinking water are based on publicly available Consumer Confidence Reports for 2019. Grades are based on whether water quality meets existing state and federal drinking water standards (i.e., Maximum Contaminant Levels, or MCLs). Based on 2019 CCRs, all Cape Cod public water supplies were graded as Excellent. The 2019 State of the Waters grades for public water supplies were all Excellent, so there has been no change.

APCC is monitoring the implementation of recently finalized regulations for PFAS and will apply these to public water supplies when regulations go into effect in 2021.

Other water quality issues of concern

  • Consumer tap water quality was not evaluated and would require testing of the water coming out of consumers’ taps as well as monitoring data from water distribution systems. Water quality coming out of the tap will be affected by the age and type of pipes in the distribution system and in consumers’ homes and businesses.
  • Drinking water consumers and regulators alike need to consider that there may be other unregulated contaminants affecting drinking water quality. These include:
    • PFAS in drinking water and in aquatic ecosystems, from a wide variety of sources. APCC is monitoring the implementation of recently finalized regulations for PFAS and will apply these to public water supplies when regulations go into effect in 2021.
    • Emerging contaminants in surface water and/or groundwater:
      • Endocrine-disrupting compounds and pharmaceuticals from inadequately treated wastewater;
      • Microplastics from wastewater, stormwater runoff and atmospheric fallout;
      • Cyanobacteria (aka blue-green algae) in freshwater ponds produce toxins that are harmful to humans and animals if ingested. Public water supplies can be contaminated by cyanotoxins, and public water suppliers elsewhere are taking precautions to guard against cyanotoxins in drinking water. APCC has been monitoring cyanobacteria since 2018 and incorporated cyanobacteria into this year’s State of the Waters grading of ponds.
  • Harmful bacteria in coastal waters and freshwater ponds, lakes and streams include fecal coliform bacteria and enteric bacteria that are indicators of human and/or wildlife fecal matter. Bacteria can impact swimming beach water quality and water quality in shellfish beds. Beach water quality and shellfish bed water quality are monitored by Barnstable County and the state, respectively.
  • Mercury contamination of surface water continues to be of concern, based on the fact that this year 29 ponds and lakes on the Cape have fish consumption advisories due to the high levels of mercury. Last year the number was 24. Mercury originates from atmospheric fallout of mercury emissions from fossil-fuel-burning power plants.
  • Climate change impacts for the Northeast are predicted to include warmer air and water temperatures year-round; more precipitation; more intense storms; longer and warmer growing seasons coupled with shorter and warmer winters; shifts in populations of fish, wildlife and invertebrates; rising sea level; changes in groundwater elevations; more flooding; and changes in dynamic landforms such as those found on the Cape (e.g., dunes, beaches, floodplains). Many of these climate change predictions will impact water quality and exacerbate the harmful effects of existing pollutants.

FILLING THE GAPS: RECOMMENDATIONS FOR MONITORING

Monitoring is crucially important for tracking progress in improving and protecting water quality. Based on our findings, APCC provides the following recommendations for monitoring:

  • Monitoring of at least four more coastal embayments is needed (Chase Garden Creek in Yarmouth, Red River in Harwich, Hatches Harbor in Provincetown and Great Sippewissett Marsh in Falmouth). These embayments are listed in the 208 Water Quality Plan as coastal embayments receiving nutrients from their watersheds.
  • Pond monitoring should be expanded to many more ponds and lakes throughout the Cape, particularly those where there are swimming beaches, public access, and/or sensitive resources (e.g., diadromous fish, rare species, wildlife).
  • The PALS program is useful as a “screening tool” to identify ponds where more in-depth monitoring and assessment is needed to determine causes, extent and severity of problems.
  • Pond monitoring should be conducted more frequently than the once-a-year snapshot that is typically provided by the PALS program.
  • Newer, more recent pond data should be utilized to assess pond conditions and inform restoration and protection efforts.
  • Monitoring of pond water quality and cyanobacteria blooms should be conducted hand-in-hand so that water quality data can be used to help predict where serious cyanobacteria blooms may occur, and vice versa.
  • Public water suppliers should expand their monitoring of PFAS, emerging contaminants and cyanobacteria to help safeguard public health.

SUCCESS STORIES

Despite the challenges and the need for much greater action in every town, there have been some successes in addressing nutrient pollution. These successes include the following:

  • Barnstable County’s alternative septic system testing center has been testing efficacy of different alternative septic systems and has identified several as being potentially useful;
  • Sewer expansion projects are underway in Chatham and already completed in Falmouth for the New Silver Beach neighborhood;
  • Alternative wastewater treatment methods are being tested or utilized in towns, including permeable reactive barriers in Falmouth and Orleans and shellfish aquaculture projects in Falmouth, Barnstable, Mashpee, Yarmouth, Dennis, Orleans and Wellfleet;
  • Partnering agreements between towns to share public wastewater treatment facilities (e.g., Harwich and Chatham); including first-ever sewers installed in Harwich;
  • Groundbreaking in 2020 for the Orleans wastewater treatment facility and collection system;
  • The state’s first Watershed Permit for four towns in the Pleasant Bay watershed, designed to facilitate a coordinated effort by the towns of Brewster, Chatham, Harwich and Orleans and the Pleasant Bay Alliance to control nutrient pollution in Pleasant Bay (see Pleasant Bay Watershed Permit);
  • Intermunicipal agreement between Mashpee, Sandwich and Barnstable for nitrogen load sharing for the cleanup of Popponesset Bay;
  • Passage of state legislation in 2018 that established the Cape Cod and Islands Water Protection Fund to provide a non-property tax-based source of funds to help Cape Cod and the Islands pay for necessary wastewater infrastructure and water quality remediation efforts;
  • Pond restoration success stories have been compiled by the Cape Cod Commission. Success stories for freshwater ponds are fewer because ponds have not received the attention that coastal embayments have received;
  • Additional water quality improvement success stories can be found on the Cape Cod Commission’s website.

Finally, ecological restoration projects provide benefits for water quality as well as ecological benefits for fish and wildlife habitat. Several restoration projects that are planned, underway or completed include: Parkers River tidal restoration, Herring River tidal restoration, Childs River freshwater wetland restoration, Coonamessett River restoration, Sesuit Creek salt marsh restoration, Three Bays stormwater remediation project, Stony Brook salt marsh and fish passage restoration, and others. APCC’s Restoration Coordination Center is assisting with many of these projects and provides Cape Cod communities with assistance in planning and implementing successful restoration projects. For more information on restoration projects on Cape Cod, visit APCC’s website. 

Maps

Click on a map image below to open the corresponding PDF.

Embayment Status
Public Water Supply Status
Sewered Areas, Title 5 Septic System Areas, and Open Space Areas
Embayment Stations
Pond Status