I Coastal Nitrogen Loading Project

Final Report April, 2002

prepared by

Cape Cod Commission Water Resources Office

Nauset Marsh/ Town Cove

1 I . I I I Coastal Nitrogen Loading Report

I Project 99-03/604 FINAL REPORT I Centerville River/East Bay, Nauset Harbor/Town Cove, Popponesset Bay, and Herring River, Harwich I Prepared by: Cape Cod Commission I Eduard M. Eichner, Water Scientist/Project Manager Thomas C. Cambareri, Water Resources Program Manager Ben Smith, GIS Analyst Van Morrill, Project Assistant I Gary Prahm, GIS Program Manager I Margo Fenn, Executive Director Prepared for:

I MASSACHUSETTS DEPARTMENT OF ENVIRONMENTAL PROTECTION BUREAU OF RESOURCE PROTECTION I AND U.S. ENVIRONMENTAL PROTECTION AGENCY I REGION I

MASSACHUSETTS EXECUTIVE OFFICE OF ENVIRONMENTALAFFAIRS I Robert Durand, Secretary DEPARTMENTOF ENVIRONMENTALPROTECTION Lauren Liss, Commissioner

BUREAU OF RESOURCE PROTECTION I Cynthia Giles, Assistant Commisaiorier DIVISION OF MUNICIPAL SERVICES I Michael Rotondi, Director June, 2002

This project has been financed partially with Federal Funds from the Environmental I Protection Agency {EPA) to the Department of Environmental Protection {DEP) under a S604b Competitive Grant. The contents of this report do not necessarily reflect the views and policies of EPA or of DEP, nor does mention of trade names or commercial I products constitute endorsement or recommendation for use. I I I I Table of Contents

I Final Report Coastal Nitrogen Loading Project I June2002 Page I I. INTRODUCTION ...... 1 II. GENERAL EVALUATION PROCESS ...... 2 I A. NITROGEN LOADING LIMITS AND FLUSHING STUDIES ...... ••...... •...... 3 i. Flushing Study Characteristics ...... ; ...... 3 ii. Nitrogen Loading Limits ...... 4 I iii. Current Regulatory Setting ...... 5 B. WATERSHED DELINEATION ...... •.•...... •...... 8 C. LAND USE AND NITROGEN LoADJNG ANALYSIS ..•...... •....•..•.•...... •...... •. 9 I D. DEVELOPMENT AND IMPLEMENTATION OF MANAGEMENT STRATEGIES .....•...... 12 III. CENTERVILLE RIVER/EAST BAY SYSTEM ...... 14 I A. FLUSHING STUDY, CRITICAL LoADS, AND EXISTING AND BUILDOUTNJTROGEN LOADS .... 14 B. POTENTIAL MANAGEMENT STRA TEGJES ...... •...... 19 i. Scudder Bay, Scudder Bay/Bumps River, Centerville River - East/Centerville River, and Scudder I Bay/Bumps River/Centerville River/Centerville River-East/Centerville River-West subwatersheds 19 ii. Phinneys Bay ...... 21 iii. Whole Centerville River/East Bay system ...... 22 I C. NEXT STEPS/DISCUSSION/RECOMMENDATIONS ...... 23 IV. NAUSET HARBOR/fOWN COVE SYSTEM ...... 25 I A. FLUSHING STUDY, CRITICAL LOADS, AND EXISTING AND BUILDOUT NITROGEN LOADS ..... 25 B. POTENTIAL MANAGEMENT STRATEGIES FOR SALT POND ...... •...... 30 C. NEXT STEPS/DISCUSSION/RECOMMENDATIONS ...... 31 I V. HERRING RIVER, HARWICH ...... 34 A. INITIAL WATER QUALITY EVALUATION ...... 34 B. NITROGEN LoADING ANALYSIS ...... 38 I C. NEXT STEPS/DISCUSSION/RECOMMENDATIONS ...... 39 VI. POPPO NESSET BAY ...... 41 I A. COORDINATION AMONG MANY PROJECTS ...... 41 B. PRELIMINARY NITROGEN LOADING ANALYSIS ...... 43 C. NEXT STEPS/DISCUSSIONIRECOMMENDA TIONS ...... 46 I VII. CONCLUSIONS ...... 47 I VIII. REFERENCES ...... 49 I I I I List of Figures

I Final Report Coastal Nitrogen Loading Project I June 2002 ~e Figure I. Four Step Approach to Nitrogen Management of Coastal Waters 2 Figure 2. Local vs. System Residence Time 4 I Figure 3. Centerville River/East Bay System Watersheds 15 Figure 4. Existing Nitrogen Loading (Centerville River/East Bay System) 17 Figure 5. Buildout Nitrogen Loading (Centerville River/East Bay System) 18 I Figure 6. Nauset Harbor/Town Cove System Watersheds 26 Figure 7. Existing and Buildout Nitrogen Loading (Nauset Harbor/Town Cove System) 28 I Figure 8. Nitrogen Loading within the Salt Pond Watershed 30 Figure 9. Nitrogen Fluxes (kg/yr) in Town Cove (Teal, et al., 1983) 32 Figure 10. Herring River System Watersheds 35 Figure 11. Herring River Monitoring Locations 36 Figure 12. Popponesset Bay Subwatersheds 42

I List of Tables

Final Report I Coastal Nitrogen Loading Project June2002 I Page Table I. 1991 Buzzards Bay Project Recommended Nitrogen Loading Limits 6 Table 2. Current BBP Recommended Coastal Embayment Nitrogen Loading Limits 7 Table 3. Technical Bulletin 91-001 Nitrogen Loading Factors II I Table 4. Residence Times and Volumes in the Centerville River/East Bay Embayment System 14 Table 5. Critical and Watershed Nitrogen Loads in the Centerville River/East Bay Embayment 16 System I Table 6. Selected Potential Nitrogen Management Options Reviewed (Scudder Bay watershed) 20 Table 7. Selected Nitrogen Management Options Reviewed (Bumps River/Scudder Bay combined 20 watershed) Table 8. Selected Nitrogen Management Options Reviewed (Centerville R East/Centerville River) 21 I Table 9. Selected Nitrogen Management Options Reviewed (Centerville River/Scudder 21 Bay/Bumps River/Centerville River East/Centerville River West) Table 10. Selected Nitrogen Management Options Reviewed (Phinneys Bay) 22 I Table 11. Selected Nitrogen Management Options Reviewed (Whole Centerville River/East Bay 23 System) Table 12. Residence Times and Volumes in the Nauset Harbor/Town Cove Embayment System 25 Table 13. Critical and Watershed Nitrogen Loads in the Nauset Harbor/Town Cove Embayment 29 I System Table 14. Selected Potential Nitrogen Management Options Reviewed (Salt Pond watershed) 31 Table 15. .Measured and Project Strearnflow Measurements in Herring River System, Harwich 37 I Table 16. Watershed Nitrogen Loads in the Herring River System (Harwich, MA) 38 Table 17. Preliminary Nitrogen Loads in the Popponesset Bay Watershed 45 I I I I Executive Summary I Most coastal embayments on Cape Cod are degraded by impacts from existing development within their watersheds. Future development will further strain these ecosystems. Creating solutions to restore and protect these ecosystems requires a better understanding of how each individual embayment functions. Analyses need I to be completed to answer questions like: I) how big is the watershed?, 2) what are the nutrient loads coming from the watershed?, and 3) can the tides flush out the nitrogen quicker than it is coming in? Answers to these questions and others will help to provide the basis for developing options to restore or preserve coastal I ecosystems.

This report documents nitrogen loading assessments completed by the Cape Cod Commission for the I Centerville River/East Bay coastal system in Barnstable, the Town Cove/Nauset Marsh system in Orleans and Eastham, the Herring River system in Harwich, and the Popponesset Bay system in Mashpee and Barnstable. These assessments are part of an overall effort by the Cape Cod Commission, the state Department of I Environmental Protection, and a number of other agencies and organizations to develop basic information for all of the coastal systems surrounding Cape Cod. Similar previous assessments are currently being used in town comprehensive wastewater assessments and citizen board discussions about appropriate development. I These efforts can also be used as first steps in the process of developing water quality protection standards under the state and federal Total Maximum Daily Load (TMDL) provisions of the Clean Water Act. The Massachusetts Estuaries Project (MEP), which is being led by DEP and UMASS-Dartrnouth School of Marine I Science and Technology (SMAST), will take the next step forward by combining watershed information similar to analyses presented in this report with embayment-specific water quality and ecosystem information I through the use of embayment-specific models. The assessment of the four systems documented in this report indicate that: 1) The Centerville River/East Bay system is overloaded with nitrogen. The Town of Barnstable has I met this concern by committing to a citizen-based water quality monitoring program to help to calibrate and refine the nitrogen loading analysis in this report and has limited future development through increased minimum Jot sizes in the watershed. It is also recommended that the town consider preserving available I undeveloped land within the watershed for potential future neighborhood wastewater treatment facilities. 2) Salt Pond within the Nauset Marsh/Town Cove system is the only nitrogen overloaded portion of the system. However, limited water quality assessments indicate some nutrient sensitivity differences that I should be resolved with a more comprehensive water quality monitoring project and/or program. The Town of Orleans has recently initiated a citizen-based water quality program for the overall system, which will lay the groundwork for a MEP analysis. Prior to collection of this information, it is recommended that the Town of Eastham and the National Park Service consider interim steps to limit future nitrogen loading within the I Salt Pond watershed. 3) A comprehensive monitoring program is recommended for the Herring River in Harwich. Comparison of the nitrogen loading assessment to limited water quality monitoring funded by the Cape Cod I Commission suggests that denitrification of watershed nitrogen loads is occurring, but the monitoring results are too limited to be able to define an accurate range for the percentage removed. 4) The evaluation discussed for Popponesset Bay is a portion of the next generation of embayment I assessments that will be completed under the Massachusetts Estuaries Project. The preliminary nitrogen loading assessment presented here will be combined with water quality and tidal flushing information into a model to assist Mashpee and Barnstable with the evaluation of questions about impacts of development, I changes in wastewater treatment infrastructure, and dredging impacts.

Cape Cod Commission Final Report (June, 2002) I CoastalNitrogen Loading Project I I I. INTRODUCTION I Coastal waters on Cape Cod are under stress from increasing development within their watersheds. Submerged plants, like eelgrass, which provide habitats for scallops, I flounder, and other important commercial species, are rapidly disappearing. Free-floating plants, or algae, are better able to utilize the nutrients coming from the watersheds and often shade out, and eventually smother, the eelgrass. In some Cape Cod coastal I embayment systems, excessive nitrogen loads have created so much algal growth that the decomposing algae on the bottoms of these bays consume most of the oxygen, leaving sediments and the overlying water as virtual wastelands, inhabited only the hardiest of I creatures.

Creating solutions to restore these ecosystems requires a better understanding of how each I embayment functions. Assessments need to be completed to answer questions like: 1) How big is the watershed?; 2) What are the nutrient loads coming from the watershed? I and 3) Can the tides flush out the nitrogen quicker than it is coming in? Questions like these and others help to provide the basis for developing options to restore or preserve I coastal ecosystems. The primary contaminant of concern in these assessments is nitrogen. Nitrogen is usually the most limited of the nutrients crucial for plant growth in coastal systems. Therefore, I additional nitrogen will cause a higher level of growth throughout the system. Nitrogen is introduced into coastal waters from watershed sources and atmospheric deposition. On Cape Cod, the nitrogen from watershed sources is transported to the coast via I I groundwater or surface waters, like streams or rivers, which are also derived from groundwater. The nitrogen that gets into the groundwater comes from wastewater, I stormwater runoff, and fertilizers.

This report documents nitrogen loading assessments completed by the Cape Cod I Commission in 2000 for the Centerville River/East Bay coastal system in Barnstable, the Town Cove/Nauset Marsh system in Orleans and Eastham, and the Herring River system in Harwich, as well as portions of the assessment of the Popponesset Bay system that is I being completed in 2002 for the Massachusetts Estuaries Project (MEP). Under the MEP, a combined-linked watershed/ embayment water quality model will be prepared for each of I these systems. Each model will utilize citizen-collected water quality data, watershed land use details, and tidal hydrodynamic information. These models will then be available to answer "what if" scenarios regarding various nitrogen management strategies. This I report and the MEP are part of an overall effort by the Cape Cod Commission, the state Department of Environmental Protection, and a number of other agencies and organizations to develop basic information for all of the coastal systems surrounding Cape I Cod. Reports documenting this overall effort have included: Cape Cod Coastal Embayment Project (Eichner, et al., 1998b); Pleasant Bay Nitrogen Loading Study (Eichner, et al., 1998a) and Ashumet Plume Nitrogen Offset Program (Ramsey, et al., 2000). I Additional information about the Massachusetts Estuaries Project can be reviewed at: I http://www.state.ma.us/ dep/smerp/smerp.htm. Cape Cod Commission 1 Final Report (June, 2002) I I II. GENERAL EVALUATION PROCESS I In order to determine the amount of nitrogen getting into each of the project systems, the Cape Cod Commission project staff utilized a four step process. These steps include: 1) I conducting a flushing study to determine how long it takes for water within an embayment and its subembayments to be exchanged by the tides and the amount of nitrogen that the ecosystems can assimilate (often referred to as "loading limits" or I "critical loads"); 2) delineating the watershed to the embayment and subembayments; 3) evaluating the steady-state nitrogen load coming from existing development within its watershed and subwatersheds and the potential future load based on the complete I development of undeveloped land I Figure 1. under existing zoning; Four Step Approach to Nitrogen and 4) comparing the nitrogen loads from I Management of Coastal Waters existing and future development in the II watershed(s) to the I critical loads from the flushing study and developing potential I nitrogen management options based on this comparison (Figure 1). I This process will be Flushing Study and Water Table and modified under the Watershed Delineation I Critical Load Massachusetts Estuaries Project Ill (MEP) by including I water quality information and preparation of water I quality model for the determination of the I "critical loads". Comparison of General descriptions of Nitrogen Loads this process are I Land Use/Buildout to Critical Load -> described below and Analysis and Management Options system-specific I Nitrogen Loading findings are listed in 0:81tal t-U,:gm Lcadl'{IFrojec1: sections that follow. Qpe, Cb:ICbmrri 11icn 2002 I I Cape Cod Commission 2 Final Report (June, 2002) I I

I A. Nitrogen Loading Limits and Flushing Stndies Selecting how much nitrogen is appropriate for a coastal system is a difficult task with I many factors to consider and understand about each individual embayment. The system might function best (highest level of biodiversity) at a low nitrogen load, but this level might not be attainable given the existing level of development within a watershed. I Management decisions have to be considered; clams may thrive at a higher level of nitrogen load than is best for maximum scallop growth. Coming up with an appropriate nitrogen limit is based on determining the characteristics of a coastal system and then I publicly discussing the water quality expectations of the public and the willingness to pay for a given solution. One of the first steps in characterizing a coastal system is I determining how rapidly the tides exchange the water within the system.

i. Flushing Study Characteristics I Tidal flushing studies generally begin by determining the volume of water within the system. This is accomplished by collecting depth (or bathymetric) readings that are corrected for tidal height and are of sufficient number to characterize subbasins within the I system. Usually during the course of collecting these readings, observations about sediment consistency are collected. A number of tidal depth recorders (TDRs) are often installed at this same time. TDRs are remote data collectors that measure the tide height at I a regular interval (usually minutes). These TDRs are left in place over a period of days (usually the entire lunar cycle, which is approximately 30 days) to provide a data set of the I tidal movements in the system. accurately predict the tidal movements observed during the data collection period, this I model can be used to determine how long it takes for the water within a given embayment, or section of the embayment, to be exchanged by the tidal water coming into the system. This information can be supplemented with temperature, salinity, or nitrogen I data to develop a water quality component to this model. The Massachusetts Estuaries Project will incorporate nitrogen and other water quality data into the evaluation of each I embayment. Some portions of coastal systems exchange water more slowly than other parts of the same system; these areas often have poor water quality. A tidal flushing model can identify I these areas and these subembayments can be assigned their own flushing time. Evaluations of residence times in embayments suggest that segmenting of embayments leads to better evaluation of flushing characteristics (e.g.,Oliveira and Baptista, 1997). I Determining how quickly the water is exchanged, or flushed, from each sub-basin and the system as a whole is a key to determining how long nitrogen introduced from its I watershed is available for use, or uptake, by the plants in the embayment. One key consideration in determining how to evaluate flushing information for a I particular subembayment is deciding how to characterize the flushing of the subembayment. If the water quality within the larger embayment, which feeds into the I Cape Cod Commission 3 Final Report (June, 2002) I I

I subembayment, is worse than the water quality within the subembayment, one would want to evaluate how long the water within the subembayment takes to flush all the way I out of the larger embayment. This flushing time is known as a system residence time (Figure 2). If the water quality is better in the larger embayment, one would want to evaluate the flushing time to get water out of the subembayment and into the larger I embayment. This is known as a local residence time {see Figure 2). The system residence time is longer than the local residence time and the difference between the two generally I increases the further a subembayment is from the mouth of the system.

ii. Nitrogen Loading Limits I Studies of coastal systems around the world have indicated that increased nitrogen loading can dramatically increase the productivity and alter the ecosystem characteristics of coastal waters (Nixon, 1983; Nixon, et al., 1986; USEPA and EOEA, 1991; Valiela, et al., I 1992; NRC, 1993; NRC, 2000). However, determining the appropriate level of nitrogen loading tends to be rather site-specific and can become more complicated by factors that will alter the expected nitrogen load, its measurement, or its impacts. These factors can I include: internal nitrogen loads to the embayment from its sediments {deposited by growth during previous years), carbon-rich soils or I large lakes in the embayment watershed (can allow denitrification of nitrogen I loads prior to discharge), and coastal wetlands {can I denitrify watershed nitrogen loads if they flow through the wetland). Collecting I information about these features can help to clarify the existing load to the I system, but often raises additional questions to be resolved through additional I assessments. Communities Local Residence Time System Residence Time have to weigh the benefits of Figure 2. Local vs. System Residence Time additional studies with the I cost of the studies and the information they will provide. Ultimately, however, a watershed community will need to weigh these issues and make a decision about whether conditions within an embayment are desirable and how much it is willing to spend to I either restore the embayment or preserve its condition. I A community has to make this decision because desirability is often a difficult question for coastal water quality scientists to answer because any ecosystem will adapt to its inputs. I Cape Cod Commission 4 Final Report (June, 2002) I I

I In the case of a nitrogen overloaded system, the ecosystem's function will result in: loss of shellfish due to lack of oxygen, disappearance of eelgrass, bottom sediments producing hydrogen sulfide (rotten egg) odors, and macroalgal mats becoming the dominant plant I species. This system is relatively unstable due to its lack of species diversity, however people will still be able to moor their boats in this system. On the other hand, a less I impacted system will provide boat mooring and have abundant shellfish, swimmable waters, and a more diverse, stable, and sustainable ecosystem.

I Rather than trying to address the desirability of one system over another, most coastal water quality scientists try to determine what sort of ecosystem conditions will be seen at various nitrogen loading levels and provide this information for consideration by the I general public. These conditions tend to focus on one or two parameters that are key determinants for the stability or "health" of the ecosystem. These factors could be dissolved oxygen, chlorophyll concentrations, and/ or eelgrass coverages. Much research I has been focussed on determining the relationship between these factors and nitrogen loads (e.g.,Valiela, et al., 1992).

I Unfortunately, while the assessment tools have improved over the past 10 years, this research has not been able to provide "crystal clear" results that most people desire. As with most relationships in nature, the factors and nitrogen loads are interrelated in I complex ways that vary from one embayment to the next. The embayment-specific analyses completed below focus on trying to make recommendations about management I with an acknowledgement of the uncertainties and recommendations about where additional information will be useful. The linked watershed/water quality models that will be prepared during the Massachusetts Estuaries Project will be another step toward a I better understanding of the ecosystem functions within embayments. The acceptability of coastal water ecosystems needs to be addressed by the fovolved I communities, hopefully with detailed assessment information from scientists. This type of discussion about the consequences of land use decisions has not regularly occurred. However, recent changes in regional, state, and federal regulations may bring this issue to I the forefront of community decisions.

I iii. Current Regulatory Setting Arriving at an appropriate nitrogen loading limit for a watershed is somewhat further complicated by the general Jack of clear direction in both state and federal regulations. I Regionally, Cape Cod has been interested in addressing this issue since the 1980s. The Town of Falmouth adopted regulations requiring evaluation of nitrogen impacts on coastal ponds in 1985, as well as setting concentration-based nitrogen limits. This process I also led to the creation of the Falmouth Pond watchers program, which has provided citizen collected water quality information that has been gathered in scientifically I appropriate fashion. In the early 1990s, the Cape Cod Commission developed the Regional Policy Plan, a planning and regulatory document required by the legislative act I Cape Cod Commission 5 Final Report (June, 2002) I I

I under which the Commission was created. The Plan included a provision to protect coastal water quality by establishing nitrogen loading limits, or "critical loads", for each embayment. As guidance for establishing these limits, the Commission initially utilized I nitrogen loading limits recommended by the Buzzards Bay Project (BBP) (USEPA and I EOEA, 1991) (Table 1). Table I. 1991 Buzzards Bav Proiect Recommended Nitrogen Loading Limits. Embayment ORW/SA SA SB I Shallow -flushing: 4.5 days or Jess 100mg/m3Nr 200mg/m 3Nr 350 mg/m3Nr I -flushing: greater than 4.5 days 5 g/m2/yr 15 g/m2/yr 30 g/m2/yr Deen - select rate resulting in lesser 130mg/m3Nr 260mg/m 3Nr 500mg/m 3Nr I annual loading 10 g/m2/yr 20 g/m2/yr 45 g/m2/yr Note: Vi= Vollenweider flushing term VF r/(l+sqrt(r)) P flushing time (yrs) I source: USEPA and MA EOEA, 1991 These recommended limits were developed after a review of water quality information from embayments around the world and utilize the descriptive categories in the DEP I coastal water classification regulations (Outstanding Resource Water (ORW), SA, SB) as guidance. The state surface water regulations (314 CMR 4) classify a limited number of specific water segments and bodies. The regulations state that all coastal waters not I specifically listed in the regulations are classified as SA waters. The BBP tiered nitrogen loading limit system for shallow and deep embayments incorporates flushing times for I rapidly flushed systems and areal measures for less rapidly flushed systems (see Table 1). The tiered limits in Table 1 use the state categories, but the meaning of categories in the I regulations and the limits recommended by the BBP are different and the BBP limits are not incorporated into the state regulatory structure. For example, the ORW (Outstanding Resource Water) designation is not similar in both cases. The state uses the ORW I designation for "anti-degradation" areas; areas where water quality should not be further degraded by pollutants. Since the BBP used the ORW designation as a limit, waters that have nitrogen loads below the limit could theoretically be degraded with more pollutants I up to the limit. In addition, the ORW designation can be assigned to SB waters under the state regulations (based on the descriptive standards and uses in the regulation), while the BBP recommended standards assume that SB waters can be loaded at a higher nitrogen I load. The BBP recommended limits should be considered separately from the state surface water classification regulations categories.

I In order to utilize these limits, one needs to have a flushing time for an embayment or subembayment system, the bathymetry, and volume of the system. Once this basic I information has been developed, these values and the appropriate BBP limit are used to

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I calculate a "critical load" or an annual mass of nitrogen that the system can assimilate at the recommended limit without becoming more eutrophic or impaired.

I Since these initial values were released, the Cape Cod Commission, Buzzards Bay Project, the UMASS-Dartmouth School of Marine Science and Technology (SMAST), the Marine I Biological Laboratory, the Woods Hole Oceanographic Institution, the Department of Environmental Protection, and other agencies and organizations have been reviewing the ten year history of coastal water quality assessments and regulations on Cape Cod. As I part of this review, the BBP released draft revised nitrogen limits, which decrease the recommended amount of nitrogen allowable in coastal waters (Costa, et al., 1999) (Table 2). This recommendation follows on a similar recommendation made by the Commission I during a limited review of water quality information during the Cape Cod Coastal Embayment Project (Eichner, et al., 1998b). The BBP recommended limits in Table 2 were utilized to determine the nitrogen limits for the coastal systems reviewed during this I project. Project staff compared the nitrogen loads to the limit based on the current state classification of the project water bodies, as well as compared to the ORW limit.

I Table 2. Current BBP Recommended Coastal Embavment Nitrol(en Loading Limits. Embavment 0RW/SA SA SB Shallow 50mg/m3Nr 150mg/m 3Nr 300mg/m3Nr I Deep 75mg/m3Nr 200mg/m3Nr 400mg/m3Nr Note: Vr=Vollenweider flushing term Vr= r/(l+sqrt(r)) r= flushingtime (yrs) I source: Costa, et al., 1999 The Massachusetts Estuaries Project (MEP) will develop embayment-specific limits that I will incorporate some assessment of natural background conditions. The linked water­ quality /watershed models developed for each embayment will incorporate land use nitrogen loads, tidal flushing information, watershed delineation, and water quality I information. Using these models, MEP investigators will be able to determine what nitrogen loads and concentrations would be expected if there was no development in a given watershed, as well as determining what concentrations and loads should be I expected when all land is developed in the watershed or other "what if" scenarios. The MEP is an effort coordinated by DEP and SMAST, while involving significant participation by the Cape Cod Commission and the US Geological Survey. The Popponesset Bay I section of this report documents one portion of the MEP evaluation that will be completed for the Bay, although the findings reported here may be modified as other portions are I completed. Although the Cape Cod Commission has used the BBP recommended limits in regulatory I decisions for over 10 years, current Massachusetts state regulations do not directly address nitrogen limits for coastal water quality, but the surface water regulations suggest the use of best available technologies for direct wastewater discharges into the cleanest waters I (314 CMR 4.04 (5)) and Title 5 requires density limitations for septic systems within watersheds to "nitrogen sensitive coastal embayments" (310 CMR 15.214-15.217). The

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I surface water regulations tend to focus on the impacts from direct point sources, such as outfall pipes. These regulations state that nonpoint pollution sources of nutrients (such as septic systems) "shall be provided with all reasonable best management practices for I nonpoint source control." Since the nitrogen sensitive coastal embayments language is in Title 5, Commission staff have suggested to local boards of health that they have the I power under the local upgrade provisions of Title 5 to designate their embayments, however staff have also counselled local boards to consider the potential takings issues associated with small lots within these watersheds. DEP has not provided guidance on I implementation of this portion of Title 5 since it was adopted in 1995.

State regulations regarding coastal water quality may be due for a significant change I within the next five years. Aside from any changes that are likely to occur due to results from the MEP, the US Environmental Protection Agency (EPA) has promulgated regulations to more fully implement the Total Maximum Daily Load (TMDL) provisions of I the Clean Water Act. These regulations require states to develop water quality management plans for all water bodies that have been listed as impaired by the state. The 1998 state 303d (TMDL) list has over 900 "impaired" surface waters I (www.epa.gov/ owow / tmdl/ states/ matmdltables.html). However, this list does not include nutrient concerns for any of the systems identified as having nitrogen problems in the Cape Cod Coastal Embayment Project (Eichner, et al., 1998b) or through Falmouth I Pond Watcher monitoring data (Howes and Goehringer, 1996). These systems include areas with extensive documented water quality impairments, such as Popponesset Bay, I West Falmouth Harbor, Great Pond, Bournes Pond, and Prince Cove. Since it is likely that state funding priorities will be directed toward developing TMDL programs for waters listed on the 303d list, Commission staff are concerned that impaired Cape Cod waters I have not been included in the state list.

I B. Watershed Delineation The porous and highly permeable characteristics of the glacial-derived sand deposits of Cape Cod allow rapid infiltration of precipitation. This rapid recharge and absence of I exposed bedrock (Oldale, 1969) means that watershed delineations on Cape Cod are generally determined by the elevation of the groundwater and its direction of flow, rather than by the land surface topography (Cambareri and Eichner, 1998). Each coastal I embayment watershed is defined as the land area that captures recharge that eventually discharges into the embayment. The outer boundaries of a coastal system are delineated based on upgradient water table readings. Following the completion of a tidal flushing I study and segmentation of the system into subembayments, subwatersheds to each of the subembayments can be delineated.

I The Cape Cod Commission developed a regional water table map during the Cape Cod Coastal Embayment Project (Eichner, et al., 1998b). This regional water table map was I created from over 1,000 water table readings and utilized readings from the following lens-wide regional water table mapping projects, among others: Sagamore (Cambareri

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I and Eichner, 1998), Monomoy Gohnson and Davis, 1988), Nauset (Eichner and Cambareri, 1997), Chequesset (Eichner and Cambareri, 1997), Pamet (Cambareri, et al., 1989), and Pilgrim (LeBlanc, et al., 1986). A complete list of the studies reviewed in the preparation of I the regional water table and watershed maps is included in the appendix of the Embayment Project report. The watersheds to the large embayment systems delineated I based on this map were formally adopted for regulatory and planning purposes by Barnstable County during the 1996 approval of the Regional Policy Plan (CCC, 1996). The watersheds and subwatersheds delineated during this project are based on the regional I water table map completed during the Cape Cod Coastal Embayment Project. The USGS has recently produced a refined groundwater model of the Upper Cape region I around the Massachusetts Military Reservation (MMR) (Masterson and Walter, 2000). This model has been used by the USGS to delineate watersheds to selected coastal embayments (Popponesset Bay, Great Pond, Green Pond and Bournes Pond). A similar I effort is being completed for the remainder of the Cape under the Massachusetts Estuaries Project. Once completed, this set of models will be a tremendous tool for groundwater investigations, including evaluation of fresh water ponds and river recharge areas to be I completed under the MEP. Details of the application of this model to the Popponesset Bay I system are discussed below. C. Land Use and Nitrogen Loading Analysis In order to determine the potential water quality impacts of watershed development upon I a coastal embayment, an estimate of the amount (or "load") of nitrogen corning from the watershed needs to be developed. This effort usually involves a number of simplifying I assumptions, including expected wastewater treatment levels, housing occupancy rates, fertilizer application rates, precipitation and recharge amounts, runoff nitrogen concentrations, and steady-state conditions. Nitrogen loading analyses can be completed I in a number of ways, depending on the information that is selected and the tools available to assess the information. Following the estimate of existing nitrogen loading, a similar estimate is completed for a future scenario when all the land in the watershed is I developed (i.e., buildout). This future estimate is based on current zoning within the watershed.

I In general during this project, staff utilized town parcel data and assessors information as basic land use materials for completing the project nitrogen loading analyses. Town parcel information is first linked to assessors land use classifications (i.e., state class codes) I (MADOR, 1991). Using this combined database, a map of the watershed area is created using the Cape Cod Commission Geographic Information System (GIS). Parcels at least half in the watershed are included in the watershed unless the inclusion (or exclusion) of I the entire parcel creates a significant difference between the parcel-delineated watershed and the water table-derived watershed. Portions of parcels are added or subtracted to I attain a less than 2% difference between the parcel and delineated watersheds. Commercial, industrial, and government land uses are field checked and water use and/ or

I Cape Cod Commission 9 Final Report (June, 2002) I I

I Title 5 wastewater estimates for these parcels are determined. This information is incorporated into the GIS and frequency tables of land use types are produced from the GIS. Wastewater, lawn area, and impervious surface area estimates are developed and I combined within spreadsheets containing the land use frequency information. Nitrogen loads are assigned to the various nitrogen sources and a total nitrogen load within a I watershed is determined. The analysis of Popponesset Bay described in this report is slightly different than the I others. In the case of land use in the Bay watershed, assessors information was obtained from each of the towns, water use information was obtained from the Mashpee Water District, Sandwich Water District, and Cotuit Fire District, and a impervious surface GIS I coverage was obtained from the Mashpee Planning Department. These databases were combined using the Commission GIS and were used to estimate nitrogen loads. Details of I this analysis are described below. The nitrogen loads developed for the watersheds other than Popponesset Bay use a modified form of the nitrogen loading calculations in Technical Bulletin 91-001 (TB91-001), I which was developed by the Commission for regulatory reviews (Eichner and Cambareri, 1992). The TB91-001 method averages the wastewater flow estimate for residential dwellings (110 gpd per bedroom) with a wastewater flow based on average occupancy I within the town (55 gpd per person X # of people per dwelling). The watershed analyses assume residential houses have three bedrooms with multiples of three for two family (2X) and multi-family (3X) residences. In these watershed analyses, the residential wastewater I estimate is further reduced by accounting for the estimated seasonal occupancy; the percentage of houses that were occupied at the time of the 1990s Census is multiplied by I the calculated residential wastewater flow. The houses unoccupied at the time of the Census are assumed to be summer residences and occupied by five people for a three month period. This summer occupancy results in a tripling of the year-round population, I which is the estimated population increase associated with summer visitors on Cape Cod (CCC, 1996). Water use information for non-residential properties is usually used to estimate their wastewater flows, but if this is not available, Title 5 estimates are used. I Other nitrogen loading factors used in the analyses are the same as discussed in TB91-001 (Table 3). I I I I

I Cape Cod Commission 10 Final Report (June, 2002) I I I

Table 3. Technical Bulletin 91-001 Nitrogen Loadin Factors I NITROGENCONCENTRATIONS (m!!/1): RECHARGERATES (in/vr): Wastewater 35 Impervious Surfaces 40 Road Run-off 1.5 Natural Areas I Roof Run-off, Direct Precipitation on 0.75 Falmouth, Bourne 21 Embavment Natural Area Run-off 0.05 Sandwich, Mashpee 19 I BEDROOMSPER SINGLE FAMILY HOUSE 3 Barnstable, Dennis, Y arrnouth 18 AVERAGELAWN SIZE (ft2) 5,000 Brewster, Harwich 17 NITROGENFERTILIZER RATE Chatham, Orleans, Eastham, 3 16 I (lbs/1,000 ft2oflawn) Wellfleet, Truro, Provincetown I Source: Eichner and Cambareri, 1992 Future development potential within watersheds is based on the number of parcels classified as "developable" by the town assessors. The total number of potential I residential units is determined by evaluating each parcel; if a parcel can be subdivided into two or more parcels under current zoning, it is counted as having the highest number of potential parcels based strictly on lot size. This evaluation method does not account for I other zoning or assessors issues, such as frontage requirements or developable lots that are classified as "undevelopable", but it is a reasonable first approximation of potential residential lots. Commercial and industrial developable parcels are also divided based on I the underlying zoning and future wastewater nitrogen loads from these lots are assumed to be equal to the average of existing commercial and industrial land uses within the watershed or Title 5 estimates are used if projected land uses are available from the I respective town planner. I Under the Massachusetts Estuaries Project, it is anticipated that the nitrogen loading analyses will utilize average occupancy modified by seasonal residency for residential properties identified in assessors databases. This process is similar to the one described above, but wastewater flows are not adjusted upward by averaging them with Title 5 flows. Nomesidential properties will be treated the same as described above and nitrogen loads from golf courses, landfills, sites with Groundwater Discharge Permits, and other I relatively uncommon landuses will continue to be addressed on a site by site basis. It is also anticipated that nitrogen loads will be modified by any measured attenuation in large freshwater ponds in the coastal watersheds. Existing data collected during the summer of I 2001 and 2002 under the Cape Cod Pond and Lake Stewardship (PALS) program, which was developed by the Cape Cod Commission and School of Marine Science and Technology (SMAST)at UMASS-Dartmouth, and available historic data will be used to I determine any nitrogen losses within freshwater ponds. Nitrogen loading factors will initially be based on those included in TB91-001 (Eichner and Cambareri, 1992), although a I current project by SMAST may lead to modification of the fertilizer application rate and

I Cape Cod Commission 11 FinalReport (June, 2002) I I

I assumed residential lawn size. In addition, calibration of the water quality models may lead to more refinement of some of the nitrogen loading factors.

I Details about data utilized in this project's analyses and results of the nitrogen loading I assessments are described in the sections on each of the project embayments. D. Development and Implementation of Management Strategies I During the final step of the four step process, the nitrogen loads developed in Step III are compared to the critical nitrogen loads developed in Step II (see Figure 1). If the nitrogen load from either existing or future development within the embayment watershed exceeds I a critical load, management strategy options have been developed to reduce the nitrogen load impacting the embayment.

I Management options developed for project embayments with excessive existing nitrogen loads need to address existing development within the watersheds. Embayments that will exceed critical loads only when future development occurs have additional options that I address future or build-out nitrogen loading scenarios. Project staff have considered management strategies that have included reductions in nitrogen loads from wastewater and lawn fertilizers, dredging of embayment systems to increase flushing and increase I critical loads, and purchase and preservation of developable land as open space.

Since wastewater is usually the largest contributor to the overall nitrogen load within a I watershed, development of the potential management options also consider technologies to reduce nitrogen in wastewater effluent. DEP currently allows a 25 ppm nitrogen I effluent concentration for residential recirculating sand filters (RSFs) and a 19 ppm nitrogen effluent concentration for other denitrifying systems (Ruck, Bioclere, FAST). On­ site system manufacturers and designers are gathering data to support lower assigned I nitrogen concentrations. In cases where centralized treatment facilities are considered as wastewater management options, 10 ppm and 5 ppm nitrogen discharges are considered. The 10 ppm nitrogen discharge concentration is conventionally assigned as a discharge I limit on tertiary treatment facilities by DEP under the Groundwater Discharge Permit Program. A discharge concentration of 5 ppm is generally difficult to consistently maintain for conventionally designed tertiary plant without extensive management of the I plant or incorporation of large amounts of flow (>100,000 gpd), although lower concentrations (e.g.,3 ppm) could be obtained at higher flow rates. These concentrations and their accompanying technologies should be considered when reviewing the I management options presented for each of the embayments below. Costs of operation, maintenance, and management of these treatment systems are not considered in the I nitrogen management options. This report presents potential nitrogen management strategies to meet the various I nitrogen limits considered except for Popponesset Bay. Implementation and adoption of management strategies will require further discussions within and among the involved

I Cape Cod Commission 12 Final Report (June, 2002) I I

I communities. Popponesset Bay and the other systems evaluated in this report will be the subject of additional analyses to be completed under the MEP.

I Nitrogen loading assessments similar to those in this report have been shown to be reliable measures of likely water quality impacts and valid planning evaluations. However, the I simplifying assumptions used in these analyses can cause the results of these assessments to be called into question. MEP-type analyses, incorporating water quality information, can confirm the estimated nitrogen loadings and will incorporate limited evaluation of I benthic habitat quality and historic and existing eelgrass coverage. It is envisioned that the MEP will provide communities with a target load for a healthy coastal ecosystem and tools to evaluate interim steps toward the target. Additional evaluations of costs, I treatment technologies, management strategies will be necessary to implement the MEP findings. Commission and DEP staff are currently working on efforts to assist with these I additional evaluations and implementation of their findings. I I I I I I I I I I

I Cape Cod Commission 13 Final Report (June, 2002) I I I III. CENTERVILLE RIVER/EAST BAY SYSTEM

I A. Flushing Study, Critical Loads, and Existing and Buildout Nitrogen Loads In 1995, the Cape Cod Commission provided $15,000 to conduct a tidal flushing study of the Centerville River /East Bay coastal system, which was subsequently completed by I Aubrey Consulting, Inc. (ACI, 1996). As part of the study, four temperature-depth recorders (TDRs) were installed March 19, 1996 and were removed on May 21, 1996. The I TDRs recorded pressure and water temperature every 10 minutes. Bathymetric information was collected on May 14, 1996 using a differential global positioning system. Bathymetric and tidal information were incorporated into a tidal model that provided I · flushing rates and basin volumes for the subembayments presented in Table 4. Watersheds were subsequently delineated by Commission staff (Figure 3) and are incorporated into the Marine Water Recharge Areas map, which accompanies the RPP I (CCC, 1996).

I Table 4. Residence Times and Volumes in the Centerville River/East Bay Embayment System ACI Section Residence Time Subembayment Volume number(s) (days) I (m3) Local System Phinneys Bay l 6,790 1.69 230.62 East Bay 2 412,603 0.51 I Centerville R/Bumps R/Scudder Bay 3/4/5/6/7 504,670 0.69 1.27 Bumps River/Scudder Bay 4/5 168,683 0.58 3.18 I Scudder Bay 5 87,400 0.60 6.38 Centerville R East/Crai_gville 617 133,877 0.68 3.57 Craigyille 7 63,685 0.51 7.51 I WHOLE SYSTEM 924,682 1.14 Subembayments and AC! segments are identified on Figure 3. All data from AC! (1996).

I The tidal flushing study also includes a modelling review of the impact of three potential dredging scenarios on the flushing times: 1) dredging 75,000 cubic yards (yd3) to create a minimum 4 ft depth channel from the East Bay inlet to the public boat landing at Hayward I Road, 2) dredging a total of 185,000 yd3 to create the channel in scenario 1 and deepen the boat basin in the northwest portion of East Bay, and 3) scenarios 1 and 2 plus a central channel along the Bumps River between Scudder Bay and Centerville River for a total I dredge volume of 220,000 yd3. This review concluded that these dredging scenarios generally would slightly lengthen residence times. Thus, dredging under these various I scenarios would be unlikely to improve water quality within the system. I

I Cape Cod Commission 14 Final Report (June, 2002) I ------

Figure 3. CentervilleRiver/East Bay Watersheds

lo..!. (Jl

0 Centerville River East Bay Embayment

Centerville River West (3) ,-...... § !" 1 0 1 Miles N Coastal Nitrogen Loading Project 0 0 Note: subwatershed numbers correspond to ACI ( 1996) segments Cape Cod Commission, 2002 ~ I

I Using the tidal volume, local residence times, and the recommended nitrogen loading limits listed in Table 2, project staff developed critical loads for the various subembayments and the system as a whole (Table 5). The Centerville River/East Bay I coastal system is not specifically listed in the state surface water classification regulations (314 CMR 4), so its classification falls under the default provisions of the regulations, I which classify all unlisted coastal waters as SA.

Table 5. Critical and Watershed Nitrogen Loads in the Centerville River/East Bay Embayment I System % AC! Watershed increase Critical Load Subembayment Section Nitrogen Load (kg/yr) Area (kg/yr) I numbers inN Load acres Existing Buildout ORW SA Phinneys Bay 1 13 141 141 0 78 235 I East Bay 2 894 9,307 11,195 20 15,317 45,950 Centerville R/ BumpsR/ 3/4/5/ 7,222 91,077 102,183 12 13,929 41,786 I Scudder Bay 6/7 Bumps River/ 3,354 42,404 46,955 11 5,519 16,558 Scudder Bay 4/5 I Scudder Bav 5 1,292 20,290 22,193 9 2,766 8,299 Centerville R East/ 6/7 3,766 48,047 54,570 14 3,748 11,244 I Craigville Craigville 7 3,470 44,386 50,579 14 2,364 7,092 WHOLE 8,128 100,525 113,519 13 15,620 46,860 I SYSTEM Subembayments and AC! segments are identified on Figure 3. ORW and SA critical loads based on loading limits in I Table 2, which represent a 0.05 and 0.15 ppm addition, respectively, to background nitrogen concentrations.

Table 5 also includes the watershed nitrogen loads developed for the various aggregations I of subwatershed areas. The comparison between the watershed and critical nitrogen loads under existing conditions is provided in Figure 4, while Figure 5 provides the comparison I to buildout conditions. In general, these analyses show that nitrogen loading to most of the system exceeds both of the critical loads except for East Bay. Various groupings of adjacent waters and I watersheds also exceed the critical loads. When the whole system, including East Bay, is considered, the existing nitrogen load exceeds the recommended limits. The projected nitrogen loading associated with buildout in most of the watersheds will increase the I existing nitrogen load by between 11 and 14 percent. I

I Cape Cod Commission 16 Final Report (June, 2002) I ------Figure- 4. ------Existing Nitrogen Loading Centerville River /East Bay Coastal System

85,000 ~------~ Centerville R/ Bumps River/ Scudder Bay 65,000 Critical Limits ~ 6'o 6 ~ 45,000 -•1-----• ~~:~: 'o "'0 ....l .,s::; g Z 25,000 '-' .2: ~ a.i 0:: East Phinney's Bay 5,000 Bay Critical Load Scudder Bumps River/ Centerville R Entire Bay Scudder Bay East/ Craigville -15,000 System

-35.000 -L----

-55.000

Coastal Nitrogen Loading Project Critical Nitrogen Loads (ORW and SA) are based on 0.05 and 0.15 ppm addition to background Cape Cod Commission, 2002 ------Figure 5. Buildout Nitrogen Loading Centerville River /East Bay Coastal System

105,000 -r------~

85,000 --1------~ Centerville River East/ ~" 0.0 Craigville C 65.000 Bumps River/ ~ --1·□ 0Rw­ 0 Scudder Bay .....l OSA Craigville i::

East Bay

Critical Load IJ Phinney's Bay Entire -15,000 .,__ __ Centerville System River/ Bumps River/ -35,000 - - Scudder Bay

-55.000 L______,

Coastal Nitrogen Loading Project Crit.ical Nitrogen Loads (ORW and SA) are based on 0.05 and 0.15 ppm addition to background Cape Cod Commission. 2002 I

I The nitrogen loads for the various watersheds are based on 1996 assessors and parcel information. Residential nitrogen loads are based on the modified TB91-001 method discussed in the Methods section. Seventy-seven parcels in the Centerville River /East Bay I watershed are classified as commercial or industrial uses and Title 5 wastewater flows and water use information were obtained for each of these parcels and incorporated into the nitrogen loading calculations. Staff obtained three years (1996-1999)worth of water use I information for these parcels from the Barnstable Water Company and the Centerville, Osterville, Marstons Mill Water District. Nitrogen loading calculations used the average I of available information for each parcel, some of which have only one or two years of data. Water use was not available for eight of the parcels; Title 5 flow estimates were used for I these cases. B. Potential Management Strategies I Potential nitrogen management strategies have been developed for five subwatersheds and the entire Centerville River/East Bay watershed. These strategies focus on nitrogen reductions from improved wastewater treatment and/ or reduced lawn fertilizers; the I strategies do not specifically include any changes due to the recent increase in minimum lot size that was enacted by the Barnstable Town Council. The target nitrogen loads are those listed in Table 5. It is obvious from reviewing the potential strategies that additional I community discussions should occur due to the wastewater infrastructure costs that the I implementation of the strategies would require. i. Scudder Bay, Scudder Bay/Bumps River, Centerville River - East/Centerville River, and Scudder Bay/Bumps River/Centerville River/Centerville River-East/Centerville River-West subwatersheds I Figures 4 and 5 show that existing and buildout nitrogen loads within a variety of combinations of subwatersheds in the Centerville River system east of East Bay are greater than both SA and ORW critical loads for all combinations. Tables 6, 7, 8, and 9 display I some potential nitrogen management options within the selected subwatershed combinations to meet the SA and ORW nitrogen limits.

I The wastewater treatment improvements required to reduce nitrogen loads to the SA critical load in these subwatersheds have nitrogen concentrations generally associated I with tertiary wastewater treatment plants or facilities. Facilities achieving nitrogen concentrations of around 10 ppm generally treat wastewater collected from a neighborhood or a portion of a town. The analyses in Tables 6, 7, 8, and 9 also seem to I indicate that although preservation of developable lots as open space will decrease the required reduction in nitrogen treatment concentration, the decrease is relatively small. In addition, the allowable concentration levels are not high enough under any of the I strategies to consider on-site denitrifying systems as a likely solution. These analyses imply that wastewater treatment improvements and associated infrastructure changes, in conjunction with reduced fertilizer applications, are necessary to attain the SA critical I loads for this portion of the Centerville River/East Bay system. The reductions necessary

I Cape Cod Commission 19 Final Report (June, 2002) I to attain the ORW critical loads appear to be impossible without moving the majority of the wastewater discharge outside of the watersheds.

Table 6. Selected Potential Nitrogen Management Options Reviewed (Scudder Bav watershed' I Future Existing residential Nitrogen or % Nitrogen Reduction Necessary parcels Limit I Buildout preserved as open space Wastewater Fertilizer I Concentration Load SA Existing 71 % (10 ppm discharge) 15% --- SA Buildout 71 % (10 ppm discharge) 36% none I SA Buildout 79 % (7.5 oom discharge) none none SA Buildout 66 % (12 ppm discharge) 50% 121/171 I ORW Buildout 100% (0 ppm discharge) 50% none All analyses assume 1990s Census seasonal development (71 % year-round); at buildout 171 additional residential lots are projected. ORW = Critical Load based on 0.05 ppm nitrogen addition. I SA = Critical Load based on 0.15 oom nitrogen addition. Table 7. Selected Nitrogen Management Options Reviewed I (Bumps River /Scudder Bay combined watershed) Existing % Nitrogen Reduction Necessary Future or residential Nitrogen Buildout parcels I Limit preserved as open space I Wastewater Concentration Fertilizer Load SA Existing 71 % (10 ppm discharge) 28% ---- I SA Buildout 71 % (10 oom discharge) 38% none SA Buildout 80% (7 ppm discharge) none none I SA Buildout 80 % (11 PDm discharge) 50% 263/412 ORW Buildout 100% (0 ppm discharge) 50% 71/412 All analyses assume 1990s Census seasonal development (71% year-round); at buildout 412 additional residential lots are projected. ORW = Critical Load based on 0.05 ppm nitrogen addition. I SA= Critical Load based on 0.15 ppm nitrogen addition. I I

I Cape Cod Commission 20 Final Report (June, 2002) I I I Table 8. Selected Nitrogen Management Options Reviewed (Centerville R - East/ Centerville River) I Nitrogen Existing or % Nitrogen Reduction Necessary Limit Buildout I Wastewater Concentration Fertilizer Load SA Existing 87% (4.5 ppm discharge) 100% SA Buildout 90% (3.5 ppm discharge) 100% I All analyses assume 1990s Census seasonal development (71 % year-round); at buildout 559 additional residential Jots are projected. Neither current nor buildout nitrogen loading can attain ORW nitrogen limit, unless existing residential units or their wastewater nitrogen are removed from I the watershed. ORW = Critical Load based on 0.05 ppm nitrogen addition. SA = Critical Load based on 0.15 nnm nitrogen addition.

I Table 9. Selected Nitrogen Management Options Reviewed (Centerville River /Scudder Bay/Bumps River/ Centerville River-East/ Centerville River-West I Future Existing residential Nitrogen or % Nitrogen Reduction Necessary parcels Limit I Buildout preserved as open space Wastewater Fertilizer I Concentration Load SA Existing 71 % (10 nnm discharge) none --- I SA Existing 63% (13 ppm discharge) 50% ---- SA Buildout 77% (8 ppm discharge) none none SA Buildout 69 % (11 ppm discharge) 50% none I SA Buildout 66 % (12 oom discharge) 50% 367/974 ORW Existing 93% (2.5 ppm discharge) 100% ---- ORW Buildout 94 % (2 ppm discharge) 100% none I All analyses assume 1990s Census seasonal development (71 % year-round); at buildout 974 additional residential lots are projected. ORW = Critical Load based on 0.05 ppm nitrogen addition. I SA = Critical Load based on 0.15 ppm nitrogen addition.

ii. Phinneys Bay I Phinneys Bay is a small subembayment off the western portion of East Bay (see Figure 3). Current and buildout nitrogen loads are less than the SA nitrogen limit, but exceed the ORW nitrogen limit (see Table 5). Table 10 presents selected nitrogen management I options for the Phinneys Bay watershed to reduce the current and buildout loads to less than the ORW limit. Given that the wastewater treatment nitrogen concentrations are I between 11 and 18 ppm, it may be possible to meet the ORW limit within this watershed

I Cape Cod Commission 21 Final Report (June, 2002) I I

I through encouraging reduced fertilizer use and use of denitrifying septic system on all lots.

I Table 10. Selected Nitrogen Management Options Reviewed (Phinneys Bay) I Nitrogen Existing or Buildout % Nitrogen Reduction Necessary Limit Wastewater Fertilizer I Concentration Load ORW Existing and Buildout 49% (18 ppm discharge) 100% ORW Existing and Buildout 60% (14 oom discharge) 50% I ORW Existing and Buildout 69% (11 nnm discharge) none All analyses assume 1990s Census seasonal development (71 % year-round); watershed area already built-out. Current and buildout nitrogen loadings are less than SA nitrogen limit. I ORW = Critical Load based on 0.05 oom nitrogen addition.

I iii. Whole Centerville River/East Bay system The current and buildout nitrogen loads for the whole Centerville River /East Bay system exceed both the ORW and SA nitrogen limits (see Figures 4 and 5). Although the nitrogen I loads coming from the East Bay subwatershed are less than its ORW limit, the excessive loads coming from the portions of the whole system to the east of East Bay cause the loads I for the whole system to exceed both nitrogen limits. Table 11 presents selected nitrogen management options for the whole Centerville River/East Bay watershed to reduce the current and buildout loads to less than the SA and I ORW limits. The wastewater treatment nitrogen concentrations to meet the SA limit are between 12 and 17 ppm with reduced fertilizer loads. Given that these concentrations are lower than those currently given by the state DEP to on-site denitrifying septic systems, all I wastewater in the watershed would need to be treated at a facility approved under the Ground Water Discharge Permit program. Facilities approved under this program generally are assigned 10 ppm total nitrogen discharges, although lower concentrations I can be attained with higher flows/ greater aggregation. It is also worth noting that without accompanying fertilizer reductions, the wastewater treatment concentration necessary to reduce loads below the SA limit is 8 ppm, which could likely only be attained I through the use of a denitrifying wastewater facility treating greater than 100,000 gpd of aggregated flows. Further discussions would be warranted to explore the level of I aggregation, whether it would be on a neighborhood level or a watershed level. Meeting the ORW limit would likely require removing a portion of the wastewater flow from the I watershed. I

I Cape Cod Commission 22 Final Report (June, 2002) I I I Table 11. Selected Nitrogen Management Options Reviewed I /Whole Centerville River /East Bay System) Future Existing residential Nitrogen parcels Limit or % Nitrogen Reduction Necessary I Buildout preserved as ooen soace Wastewater Fertilizer I Concentration Load SA Existing 60% (13 oom discharge) 50% --- SA Existing 51 % /17 oom discharge) 100%. ----- I SA Buildout 66% (12 oom discharge) 60% none. SA Buildout 77% (8 ppm discharge) none none I ORW Existing 93% (2.5 ppm discharge) 100% ----- ORW Buildout 94% (2 oom discharge) 100% none All analyses assume 1990s Census seasonal development (71 % year-round); at buildout 1,141 I additional residential lots are projected. ORW = Critical Load based on 0.05 ppm nitrogen addition. SA = Critical Load based on 0.15 oom nitrogen addition.

I C. Next Steps/Discussion/Recommendations In general, the above nitrogen loading analyses suggest that significant changes should be I made in the wastewater treatment infrastructure in the watersheds to the Centerville River portion of the combined East Bay/ Centerville River coastal system. Given that these changes would likely require significant public investment, project staff recommend that I additional data gathering steps should be considered to better characterize the impacts of existing development within the watershed. The interim version of this report recommended that these steps could include regular water quality monitoring at stations I within the system, an evaluation of the sediments and their potential for sediment nitrogen regeneration, an evaluation of the dominant plants in the system, and a water quality sampling program for Lake Wequaquet to evaluate potential denitrification in the I lake (Eichner, et al., 2000).

Since the release of the interim report, the Town of Barnstable has begun a citizen-based I sampling program for its coastal waters. This program, which was developed in coordination with UMASS-Dartmouth School of Marine Science and Technology (SMAST), includes sampling locations in the major embayments within the town and is I being organized within the town by the Department of Public Works. In addition, the town participated in citizen-based regional freshwater pond sampling, which was I coordinated by the Commission and funded by SMAST. This sampling provided data for 29 ponds in Barnstable. Both the fresh and marine water quality sampling will provide data for use in future MEP evaluation of the town's embayments. The town also increased I minimum lot sizes within the watershed from 1 acre to 2 acres. Overall, the town has

I Cape Cod Commission 23 Final Report (June, 2002) I I

I committed staff and projected funding of $51 million over the next five years to nutrient management projects.

I Since it will take at least three years to complete the monitoring necessary to move forward with the MEP evaluation of the Centerville River system, project staff recommend I that the Town of Barnstable Board of Health consider implementing interim steps to limit nitrogen discharges within the watershed and limit use of wastewater technologies that will be expensive to retrofit to the likely higher level of treatment necessary within this I watershed. Title 5 currently provides the board with the ability to designate the Centerville River watershed as a nitrogen sensitive area under 310 CMR 15.213 - 15.217. This designation future development within the watershed would be limited to 440 I gallons per day (gpd) per acre using a standard Title 5 septic system; this is equivalent of one bedroom per 10,000 ft2 of parcel. Title 5 allows additional bedrooms if a denitrifying septic system is instalJed. Use of the nitrogen sensitive embayment designation would be I counterproductive in the long run, likely leading to instalJation of numerous denitrifying systems. These systems would not attain the necessary improvements in nitrogen treatment and would likely lead to public resistance to additional expenditures on the I wastewater infrastructure improvements necessary to protect the River system. However, because the nitrogen sensitive designation is available within Title 5, project staff suggest that the Board of Health may want to consider modifying the use of this option to use the I board's regulatory authority to further explore opportunities to aggregate flow within this watershed.

I Analysis of available lots would be similar to on-going work being completed by the town Department of Public Works to identify potential treatment plant and effluent discharge I locations within the watershed. Given the rapid development phase currently occurring on the Cape, undeveloped areas within the watershed with the potential to serve as plant or discharge locations should be considered for town purchase to preserve these options. I If all these locations are used for residential or commercial tj.evelopment uses, it is likely that a more centralized treatment facility, rather than neighborhood facilities, will be required to address water quality concerns and this facility will require a large land area I and extensive use of sewer pipes to colJect wastewater from throughout the watershed.

If the town wishes to pursue a wastewater management district or wishes to create some I time to evaluate potential options within this watershed, the District of Critical Planning Concern (DCPC) provisions of the Cape Cod Commission Act (Section 10 of the Act) could be used. These provisions could allow the town to institute a limited moratorium on I development within the watershed and use the DCPC process to facilitate community discussions regarding appropriate mitigation, nitrogen targets, and potential costs. Discussions of management options could also occur through the existing facilities I planning process or a board of health permitting moratorium to a date certain. Much of the work required to evaluate available on-site technologies, their costs, review of I developed parcels, and potential treatment and effluent disposal sites has already been completed during the existing facilities planning effort.

I Cape Cod Commission 24 Final Report (June, 2002) I I I IV. NAUSET HARBOR/TOWN COVE SYSTEM I A. Flushing Study, Critical Loads, aud Existing and Buildout Nitrogen Loads In June 1994, the CCC awarded the Town of Orleans $20,000 to conduct a flushing study of Town Cove. In October 1994, CCC and town staff learned that the National I Biological Survey (NBS) was also planning to complete a flushing study of the Nauset Harbor/Town Cove system. Town, county, and federal staff agreed that joint flushing study, which pooled $57,000, would be beneficial to all parties. The total cost of the I flushing study was approximately $57,000. The flushing study included the collection of bathymetric data, 45 to 60 days of tidal information from 10 sites, and predictions of the tidal flushing effects of one or two outlets (Aubrey, et al., 1997). Bathymetric and I tidal information were incorporated into a tidal model that provided flushing rates and I basin volumes for the subembayments presented in Table 12 and Figure 6. CCC staff delineated subwatersheds to the embayment segments identified in the flushing study report (see Figure 6). These delineations are based on water table I information collected as part of the Wellfleet Harbor project (Eichner and Cambareri, 1997) and a Orleans water table measurement study conducted by the CCC (Leab, et al., I 1995). Table 12. Residence Times and Volumes in the Nauset Harbor/Town Cove Embavment System I Subembayment Section Mean Residence Time (hours) number Volume One Inlet Two Inlet I (m3) Local System Local System Town Cove 1 3,440,000 26 59 22 48 I Mill Pond 2 200,000 10 378 9 354 Nauset Harbor 1 3 480,000 7 113 6 95 Salt Pond 4 265,000 88 2720 68 1956 I NausetBav 5 211,000 5 17 4 14 Nauset Harbor 2 6 1,130,000 2 2 WHOLE 7,620,000 14 11 I SYSTEM Subembavments and sections are identified on Figure 6. All data from Aubrey, et al., 1997.

I During 1982 and 1983, a group of scientists from the Woods Hole Oceanographic Institution coordinated by John Teal characterized a number of factors associated with nitrogen loading to Town Cove (Teal, et al., 1983). The data collected led to a number of I conclusions, including: 1) Town Cove is not nitrogen or phosphorus limited, 2) Town I Cove converts a large portion of the watershed nitrogen entering the system from

I Cape Cod Commission 25 Final Report (June, 2002) I I I

I Figure 6. Nauset Harbor/Town Cove Watersheds I I I Nauset Harbor/ Town Cove I Embayment Nauset I arbor3 Nauset I arbor2 Nauset Harborl I Mill I ond ~ 1....------F------, \ I Pditical Boundaries 1 I ape Cod National \ I Seashore I I/! 0 1 Miles

I Coastal Nitrcgen Loading Project I Cape Cod Commission, 2002 I Cape Cod Commission 26 Final Report (June, 2002) I I j I I inorganic forms to organic, particulate nitrogen, 3) no loss of nitrogen appears to occur through denitrification at the margins of the Cove, but some denitrification appears to I occur in the central portions of the Cove, 4) occasional anoxia is experienced in the middle portions of the Cove, 5) there is a net influx of nitrogen to Town Cove from its watershed and the rest of the Nauset Marsh system (17,885 to 43,800 kg/yr), and 6) it is I difficult to say that nitrogen additions to Town Cove will not lead to increased algal growth.

I Although the Teal, et al. (1983) findings state that nitrogen is not the nutrient limiting growth in Town Cove, concerns raised in the findings do suggest that nitrogen additions should remain a concern for the overall health of the ecosystem of the Cove, I as well as the rest of the Nauset Marsh system. Limited characterizations of nutrient limitation at two other sites (Mill Pond and a site in a channel south of Salt Pond Bay) found nitrogen-limited conditions during the summer months (Schraga and Roman, I 1997). Similar characterizations of nutrient limitations have not been completed for the other portions of the Nauset Harbor system. For these reasons, the analyses described I below compare the watershed and subwatershed nitrogen loads compared to the critical loads listed in Table 2.

I The Nauset Harbor /Town Cove coastal system is not specifically listed in the state surface water classification regulations (310 CMR 4), so its classification falls under the default provisions of the regulations, which classify all unlisted coastal waters as SA. I However, there is a provision within the regulations to classify waters "in or adjacent to the Cape Cod National Seashore" as Outstanding Resource Waters as well. Adjacent waters are areas "within 1,000 feet seaward of mean low water" for the purposes of I these regulations. Given that a significant portion of the Nauset Harbor/Town Cove system is located within the Seashore boundary (see Figure 6) and adjacent parts contribute tidal waters to the Seashore portions, staff has considered the entire system I and subembayments to be classified as Outstanding Resource Waters (ORW) for the purposes of the nitrogen loading calculations. Using the above tidal volumes, local residence times for both one and two inlet configurations, and the recommended I nitrogen loading limits listed in Table 2, project staff developed critical loads for the various subembayments and the system as a whole (Table 13). A comparison between I the watershed and critical nitrogen loads under existing and buildout conditions in the single inlet configuration is provided in Figure 7. The two inlet load comparison results I in a similar pattern. I I

I Cape Cod Commission 27 Final Report (June, 2002) I ------Figure 7. Existing and Buildout Nitrogen Loading Nauset Marsh/Town Cove Coastal System

5,000

Critical I I - Load Mill fond Nauset {arbor l Salt Pond ToWil Cove I I -5,000 -

-;::- -10,000 >, ...... - 6. I -15.000 -- - ·- .3 C II ~ II z.b -20.000 -- ~ i °Qi e::: -25,000 □ Existing □ Buildout ~

-30.000

'

-35,000 ~ -

-40.000

Critical Nitrogen Loads (ORWonly) are based on 0.05 ppm addition to background Coastal Nitrogen Loading Project under the single inlet configuration. Cape Cod Commission,2002 I I Table 13. Critical and Watershed Nitrogen Loads in the Nauset Harbor/Town Cove I Embavment Svstem Sub- Section Watershed Nitrogen Load % Critical Load embayment number Area (kg/yr) increase (kg/yr) inN I Load acres Existing Buildout ORW ORW 1 inlet 2 inlet I Town 1 2,379 22,604 26,962 19 61,108 71,919 Cove Mill Pond 2 566 4,756 5,990 26 9,056 10,045 I Nauset 3 267 960 1,195 24 30,883 35,957 Harbor 1 Salt Pond 4 377 6,153 6,433 5 1,451 1,857 I Nauset 5 1,974 9.030 12,882 43 189,252 235,423 Bay Nauset 6 561 1,474 1,670 13 251,209 252,321 Harbor2 I WHOLE 6,419 45,080 55,234 23 248,090 314,372 SYSTEM Subembayments and flushing study sections are identified on Figure 6. ORW critical loads based I on loading limit in Table 2, which represent a 0.05 ppm addition to background nitrogen concentrations.

I These analyses show that nitrogen loads to the whole system and most of the subembayments, except for Salt Pond, are less than the respective critical loads. Buildout nitrogen loads are expected to increase loads reaching the various I subembayments of Nauset Harbor between 5 and 43%. The nitrogen loads for the various watersheds are based on 1996 assessors and parcel information for Orleans and 1992 information for Eastham. Residential nitrogen loads are based on the modified I TB91-001 method discussed in the Methods section. Water use information was used, where available, for parcels classified as commercial or industrial. Water use information used included three years (1996-1998) of water data from the Orleans Water I Department and water use for public water supplies in Eastham (phone calls to establishments and data from Rask, et al., 1994). If water use information was not available, Title 5 flows were used based on flows obtained from the respective Board of I Health or calculated flows based on flow estimates in Title 5 (310 CMR 15). Seven commercial/industrial properties in Orleans, which are classified as developed, did not I have water use information available from the Orleans Water Department. In the entire watershed, 163 parcels in Orleans and 57 in Eastham are classified for commercial or I industrial uses, of which a total of 56 are classified as developable. I

I Cape Cod Commission 29 Final Report (June, 2002) I I I B. Potential Management Strategies for Salt Pond I Since the nitrogen load from the Salt Pond subwatershed is the only load exceeding a critical load in the Nauset Harbor system (see Figure 7), nitrogen management strategies have only I been developed for the Wastewater Salt Pond 31% subwatershed. The I majority of the nitrogen load to Salt I Pond is from the Eastham landfill (Figure 8). Project staff I Landfil reviewed water quality 59% Impervious information in wells 4% around the landfill I collected by the Turf Fertilizer Barnstable County I 6% Department of Health Figure 8. Nitrogen Loading within the Salt Pond Watershed and the Environment (BCDHE) between 1994 I and 1999. The well clusters downgradient of the landfill (MW3 S, I, D and MW4 S, D) have an average total nitrogen concentration of 81 ppm, while the average of all wells sampled is 69 ppm. These wells do not have nitrogen concentrations reported for two I sampling runs completed in 1999, so it is unclear whether the cap, which was installed on the landfill in 1997, has reduced the nitrogen concentrations emanating from the I landfill. If the nitrogen load from the landfill is completely removed, the existing and buildout I nitrogen loads still exceed the critical load for Salt Pond. A number of potential strategies to reduce nitrogen loads to the ORW critical load are listed in Table 14. These strategies focus on nitrogen reductions from improved wastewater treatment and/ or I reduced lawn fertilizers. It is obvious from reviewing the potential strategies that additional community discussions should occur due to the wastewater infrastructure I costs that the implementation of these strategies would require. I I I Cape Cod Commission 30 final Report (June, 2002) I I I Table 14. Selected Potential Nitrogen Management Options Reviewed I (Salt Pond watershed) Future residential Existing or I % Nitrogen Reduction Necessary parcels Buildout preserved as open space I Wastewater Concentration Fertilizer Load .,.____ Existing 60% (14 ppm discharge) ---- I Existing 46 % (19 ppm discharge) 65% ----- Buildout ·66% (12 PPm discharge) --- none Buildout 46 % (19 ppm discharge) 100% none I Buildout 79% (14.5 ppm discharge) ---- 33/33 All reductions are necessary to attain ORW nitrogen load. All analyses assume 1990s Census seasonal development (39% year-round) and no nitrogen added from capped Eastham landfill; I at buildout 33 additional residential lots are oroiected. The wastewater treatment improvements required to reduce nitrogen loads to the ORW I critical load in the Salt Pond subwatershed are between those associated with on-site denitrifying septic systems (19 ppm) and smaller treatment plants (10 ppm). It should be noted that the on-site nitrogen reductions must be accompanied by substantial I reductions in fertilizer applications to meet the critical load. Since the options presented in Table 14 require that no nitrogen load is coming from the Eastham landfill, further nitrogen sampling of the landfill wells should be conducted and evaluated to I assess whether additional nitrogen reductions would be necessary within the Salt Pond I watershed to offset loads from the landfill. C. Next Steps/Discussion/Recommendations In general, the above nitrogen loading analyses suggest that no significant changes I should be made in the wastewater treatment infrastructure or other nitrogen management in the watersheds to Nauset Harbor/Town Cove except for the subwatershed to Salt Pond. However, some of the nitrogen loading and water quality I information suggests that a comprehensive water quality assessment of the system should be considered to refine and confirm the nitrogen loading results, as well as I providing a firm basis for any wastewater treatment changes that the towns of Eastham and Orleans may be considering in the future.

I The Town Cove assessment by Teal, et al. (1983) indicates that the Cove is not nitrogen or phosphorus limited, but that future nitrogen additions could prompt additional algal growth in the system. The annual groundwater nitrogen load to Town Cove (22,604 kg) I estimated in this report is between two and three times higher than the load estimated

I Cape Cod Commission 31 Final Report (June, 2002) I I by Teal, et al. (1983) (Figure 9). While this load is less than the critical load for Town Cove, it is unclear without additional analysis of the water quality characteristics in the I Cove whether the factors limiting algal growth in the Cove are derived from factors within the watershed or factors related to the rest of Nauset Harbor system.

I The Schraga and Denitrification Roman (1997) 3,650 - 14,600 study indicated I nitrogen limitation Groundwater Tidal Influx during spring and 6,935 - 12,775 14,600 I summer months at TownCove Mill Pond and at a site within a channel that may I Sediment Sink Sediment Regeneration be indicative of 5,475 - 14,600 25,550 conditions within the main portion I Net Influx 17,885 - 43,800 kg/yr of the Marsh. Comparison of the I calculated average Figure 9. - Nitrogen Fluxes (kg/yr) in Town Cove (Teal, et al., 1983) total nitrogen concentrations I based on the nitrogen loading analysis to the average observed Mill Pond concentrations show that the estimated loads are insufficient to attain the observed I concentrations. In the interim version of this report (Eichner, et al., 2000), project staff recommended that a more refined analysis of the system be conducted to clarify some of the apparent I inconsistencies in the previous studies. The Town of Orleans is currently involved in a citizen-based marine water quality sampling program, which is being coordinated by the School of Marine Science and Technology (SMASI) at UMASS-Dartmouth. 1n I addition, the town participated in citizen-based regional freshwater pond sampling, which was coordinated by the Commission and funded by SMAST. This sampling provided data for 16 ponds in Orleans. Both the fresh and marine water quality I sampling will provide data for use in future Massachusetts Estuaries Project (MEP) I evaluation of the town's embayments and their watersheds. The MEP evaluation is especially critical for Salt Pond, given the results of the analysis presented above. Project staff recommend the analysis for Salt Pond should also I investigate the water quality in Minister Pond, which is downgradient of the Eastham landfill and may act as a nitrogen sink. Analysis of water quality in other ponds in the watershed should also be considered in order to assess nitrogen flows through these I systems.

I Cape Cod Commission 32 Final Report (June, 2002) I I I Since it will take at least three years to complete the monitoring necessary to move I forward with the MEP evaluation of the entire Nauset Marsh/Town Cove system, project staff recommend that the Town of Eastham Board of Health, in consultation with the National Park Service, consider implementing interim steps to limit nitrogen I discharges within the watershed and limit use of wastewater technologies that will be expensive to retrofit to the likely higher level of treatment necessary within this watershed. Title 5 currently provides the board with the ability to designate the Salt I Pond watershed as a nitrogen sensitive area under 310 CMR 15.213 -15.217. This designation future development within the watershed would be limited to 440 gallons per day (gpd) per acre using a standard Title 5 septic system; this is equivalent of one I bedroom per 10,000 ft2 of parcel. Title 5 allows additional bedrooms if a denitrifying septic system is installed. Use of the nitrogen sensitive embayment designation would be counterproductive in the long run, likely leading to installation of numerous I denitrifying systems. These systems would not attain the necessary improvements in nitrogen treatment and would likely lead to public resistance to additional expenditures I on the wastewater infrastructure improvements necessary to protect Salt Pond. However, because the nitrogen sensitive designation is available within Title 5, project staff suggest that the Board of Health may want to consider modifying the use of this I option to use the board's regulatory authority to further explore opportunities to aggregate flow within this watershed.

I Given the rapid development phase currently occurring on the Cape, undeveloped areas within the entire Nauset Marsh/Town Cove watershed with the potential to serve as plant or discharge locations should be considered for town purchase to preserve I these options. If all these locations are used for residential or commercial development uses, it is likely that a more centralized treatment facility, rather than neighborhood facilities, will be required to address water quality concerns and this facility will require I a large land area and extensive use of sewer pipes to collect wastewater from throughout the watershed.

I If Eastham or Orleans wish to pursue a wastewater management district following more extensive analysis, the District of Critical Planning Concern (DCPC) provisions of the Cape Cod Commission Act (Section 10 of the Act) could be used. These provisions I could allow the town to institute a limited moratorium on development within the watershed and use the DCPC process to facilitate community discussions regarding I appropriate mitigation, nitrogen targets, and potential costs. I I

I Cape Cod Commission 33 Final Report (June, 2002) I I I I V. HERRING RIVER, HARWICH A. Initial Water Quality Evaluation In the scope of work approved by DEP for this project, the Cape Cod Commission I proposed to complete a nitrogen loading assessment of the Herring River system in Harwich (Figure 10). This assessment did not propose to evaluate nitrogen management options, since it is clear that the Herring River system is a wetland I dominant system and the critical loads developed for embayments do not apply. Staff also recognized that water quality and tidal information would be crucial in characterizing the ecological condition of the system. In order to begin the process of I better characterizing the system, the Commission provided the Town of Harwich with $23,805 to establish monitoring locations and collect a "snapshot" of water quality I information in the lower portion of the Herring River with the expectation that a citizen monitoring program would be established in the future to gather a more comP.lete picture of water quality and tidal flow information. The snapshot effort was ttfcently I completed and documented in Horsley & Witten, Inc. (2000). Horsley and Witten, Inc. (HWI) established eight measuring points within the lower I Herring River system (Figure 11). Six of the points were water quality stations with samples collected on four dates in 1999 (8/16, 10/7, 11/12, and 12/15). Samples on 8/16 and 12/14 were collected one day following storms of at least 0.7 inches and I samples on 8/16 and 11/12 were collected during incoming tides, while the other two dates were during outgoing tides. Samples were analyzed for temperature, salinity, pH, dissolved oxygen, ortho-phosphate, total dissolved phosphorous, ammonia­ I nitrogen, nitrate-nitrogen, dissolved organic nitrogen, particulate organic nitrogen, particulate organic carbon, chlorophyll a, pheophytin, fecal coliform, and fecal streptococcus. Three measuring points were stream gauging stations and three points I were tidal gage locations. To supplement the tide gages, which recorded water levels changes over six tidal cycles, salinity readings and rough channel bathymetry were I recorded at twenty-two sites within the lower Herring River. Based on a number of different approaches (fraction of freshwater, tidal prism, and I mass balance) using the collected data, HWI estimated that the flushing rate for the tidal portion of the river is between 1.5 and 3 days. Further refinement of this flushing rate would require a more rigorous evaluation of marsh and channel elevations, as well I as additional tidal data collection.

HWI also delineated a watershed that is slightly different than the one adopted by the I Commission with the Regional Policy Plan approval (CCC, 1996) (see Figure 10). Although both watershed delineations rely on the same water table data (Johnson and I Davis, 1988), HWI felt that the surface water connections between Cornelius Pond,

I Cape Cod Conunission 34 Final Report (June, 2002) I ------

q

',.! -q•·--:~-~----················· - HAAWICH '

0 o.s 1.5 2 Mies CAPECOD l!!!!!!!!!!!!liiiiiiiiiiiiiiiiiiiiiiil!!ll!!!ll!!l!!!!!!!!!!iiiiiiiiiiiiiiiiiiiiiiiil ------Figure 11. HerringRiver MonitoringStations

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6 Tide Gage S1ation 0 Stream Gaging Station .& Water Quality S1ation CJStream Gaging, Water Quality, and Tide Gage Station

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0 0.5 1 1.5- 2 Miles - Coutal Niin,ge,, Loading Project Cope Cod Commission. 2002 I I Walkers Pond, and the lower Herring River warranted the inclusion of the additional area indicated in Figure 10 (personal communication, Neil Price, HWI). HWI attempted I to corroborate the watersheds based on water table information by comparing the expected streamflows for the areas based on average annual recharge to the streamflows measured in October 1999. The results of this method, which is I documented in Cambareri and Eichner (1998), did not agree with the measured flows. However, given that water levels in the general area at the time of the stream measurements were approaching an 11 year low (recorded December 1999), it is not I surprising that the measured flows are significantly lower than expected based on average water table conditions (Table 15). In order to better characterize the surface water flows and their relationship to the groundwater-based watersheds, regular flow I readings should be collected at a number of locations within the Herring River watershed. The measuring locations used by HWI are a useful starting point for I discussions about citizen-based streamflow monitoring network. Table 15. Measured and Project Streamflow Measurements in Herring River I Svstem, Harwich Streamflow in cubic feet per second (cfs) Location HWI Calculated Stormflow Baseflow I Designation 10/21/99 10/28/99 Herring River/Rt 6 HRl 9 4.93 3.90 Reservoir HR2 12 4.61 1.91 I Lothrop Rd. HR3 4 mix mix Entire Svstem HR7 19 Calculated flows based on watershed areas in Figure 11 and 18 inches of recharge per year. HR3 I flows were not measured due to mix of tidal flow at measuring location. All data from HWI (2000).

The uncertainties associated with the streamflow measurements also extend to the I interpretation of the collected water quality information. Because nitrogen is bioreative, i.e.,it is taken up by the plants in the system, converted between inorganic and organic I forms, and denitrified into the atmosphere, interpretation of the water quality data is constrained because some of the data was collected during the growing season (August) and some was collected during times when plants are either becoming inactive I (October) or are inactive (November, December). In addition, each of the water quality samples was taken under different tidal and storm conditions, as well as during different times of the day (10:10 AM to 11:55 AM; 1:30 to 3:45 PM; 1:15 to 3:30 PM; 8:00 I to 9:40 PM). For example, the August reading was just after a storm and during an incoming tide, while the October reading was collected during a no precipitation period (characterized as baseflow by HWI) and outgoing tidal conditions. Given that each I sample date essentially represents a different snapshot of conditions, further water quality monitoring is also warranted to clarify the range of concentrations under all of I the tidal and storm conditions.

I Cape Cod Commission 37 Final Report (June, 2002) I I I B. Nitrogen Loading Analysis Although additional water quality and streamflow information is necessary to draw I firm conclusions, staff conducted a nitrogen loading analysis of the delineated watersheds in order to begin the process of understanding nitrogen sources and sinks within the Herring River system. Nitrogen loading results based on the modified TB91- I 001 method, which is discussed in the Methods section (see Section J.C.), are presented in Table 16.

The nitrogen loads for the watersheds are based on 1998 assessors and parcel information for Harwich, 1996 information in Brewster and 1993 information for Dennis. Residential nitrogen loads are based on the modified TB91-001 method. Project I staff utilized the HWI watersheds for the nitrogen loading analysis; additional water table measurements near the ponds in the area (Cornelius, Black, Walkers, etc.) are I necessary to resolve the disagreements between the Commission and HWI delineations. Water use information was used, where available, for parcels classified as commercial or industrial. Water use information included three years (1997-1999) of water data I from the Harwich Water Department, Brewster Water Department, and the Dennis Water District. If water use information was not available, Title 5 flows were used based on flows obtained from the respective Board of Health or calculated flows based I on flow estimates in Title 5 (310 CMR 15). In the entire watershed, 64 parcels in Harwich, 4 in Brewster, and 19 in Dennis are classified for commercial or industrial uses, of which 50 are classified as developable. Ten commercial/ industrial properties in I Harwich, which are classified as developed, did not have water use information available from the Harwich Water Department.

I Table 16. Watershed Nitrogen Loads in the Herring River System (Harwich, MA Projected % Nitrogen Load (kg/yr) # of Nitrogen load increase I Watershed Area based on modified additional (kg/yr) based on inN TB91-001 residential HWI sampling load lots I acres Existing Buildout low high Upper Herring 5,513 31,575 43,332 37% 1,034 1,664 16,039 River I Lower Herring 1,761 15,385 18,083 18% 232 River Coy Brook 2,008 10,883 17,471 61% 583 2,479 4,063 Whole 9,281 57,843 78,886 36% 1,849 4,469 10,768 I Watershed Watershed areas based on HWI (2000). HWI low based on measured streamflow and lowest measured total nitrogen concentration; HWI high based on estimated streamflow based on watershed area and I recharge rate and hi«hest measured total nitrogen concentration.

Table 16 also presents nitrogen loading ranges based on the limited water quality I dataset collected by HWI. As mentioned previously, the HWI dataset essentially

I Cape Cod Commission 38 Final Report (June, 2002) I I I represents four unique snapshots of the water quality within the Herring River system. Accordingly, the ranges for the nitrogen loading based on the dataset are very wide. I The results in Table 16 indicate that significant loss of nitrogen is occurring within the system; 49 to 95% of the modified TB91-001 load, which does not include wetland denitrification, is not accounted for in the water quality samples. Loss of nitrogen due I to denitrification in wetland systems has been documented extensively (e.g., Howes, et al., 1996). However, without a full accounting of seasonal denitrification differences, benthic fluxes, nitrogen pools within the system or changes in water quality I constituents over the course of a day, it is difficult to draw definitive conclusions about I the denitrification offered by the ponds and wetlands within the watershed. C. Next Steps/Discussion/Recommendations In the interim version of this report (Eichner, et al., 2000), project staff recommended I that the Town of Harwich consider gathering additional water quality data and system characterization information, such as water levels and bathymetry, on the ponds and I wetlands within the Herring River watershed. It was stated that citizen volunteers could be the core of the sampling program. I Harwich has actively been pursuing efforts to create a citizen-based sampling program and limited data was collected during the summer of 2001 (personal communication, Frank Sampson, Harwich Water Quality Committee). This data was limited to total I nitrogen and some of its components (dissolved inorganic, dissolved organic, and particulate organic nitrogen). The town has also begun a freshwater pond sampling I program also. The sampling program that is ultimately designed for the Herring River system should include, at the very least, streamflow measurements at the following HWI measuring I locations (HR1, HR2, and HR3; see Figure 11) with periodic water quality analyses of nitrogen series, phosphorus series, dissolved oxygen, temperature, salinity, carbon, and chlorophyll a. If desired, coliform could be added to this analysis. In addition, in order I to establish denitrifying capacity of the ponds within the watershed, the town may want to consider a parallel project to develop initial characterization of the ponds I within the watershed, including a review of existing information for Long Pond and Flax Pond. A monitoring program within the River should be designed to ensure that data collected on different dates is comparable; the primary focus of the program I should be to collect most of the data during the summer with one or two samples during the winter. Collection of this type of sampling data would allow the system to I be reviewed under the Massachusetts Estuaries Project. Since the analysis at this point is somewhat inconclusive, project staff do not recommend consideration of any regulatory changes to either increase or decrease I protection of the water quality in the Herring River. Obviously, measures designed to

I Cape Cod Commission 39 Final Report (June, 2002) I I I protect other resources within the watershed, such as Long Pond, Flax Pond or I wellhead protection areas, should proceed. I I I I I I I I I I I I I I

I Cape Cod Commission 40 Final Report (June, 2002) I I I VI. POPPONESSET BAY I A. Coordination Among Many Projects When this grant project was first submitted, the Commission proposed to refine nitrogen loading estimates and management strategies for Popponesset Bay previously I completed under the Cape Cod Coastal Embayment Project (Eichner, et al., 1998b). This effort would utilize the water quality information collected by citizens under the guidance of the School of Marine Science and Technology (SMAST) at UMASS­ I Dartmouth and would be coordinated with SMAST to develop a calibrated water quality model similar to the models that are currently being developed under the Massachusetts Estuaries Project (MEP). Using the model, more refined management I options would be presented to the Town of Mashpee. These refinements would include the watersheds to the Mashpee River, Shoestring Bay, Ockway Bay (which was not I specifically addressed in the Embayment Project review), and the entire Popponesset Bay system. I Following the signing of the original grant contract in April 1999, Commission staff requested and obtained the assistance of the US Geological Survey (USGS) to complete a modelled delineation of the watershed to Popponesset Bay. Although the I Commission had prepared a detailed water table map, which was used to delineate the watershed to the Bay under the Embayment Project, the USGS had completed and refined a groundwater model of the western Cape as part of their efforts to identify I future water supply sites in and around the Massachusetts Military Reservation (Masterson and Walter, 2000). This model had the advantage of all the geologic, stream flow, and water table information collected around and at the MMR and could be used I to provide time of travel bands to various portions of the embayment and freshwater ponds within the watershed. This model was eventually used to delineate watersheds to Great, Green and Bournes Pond in Falmouth (Ramsey, et al., 2000) and it will form I the foundation of the updated model that will be used for the watershed delineations to be completed within the Sagamore Lens under the MEP.

I Following discussion with Commission and SMAST staff, the USGS used the model to create various time of travel bands around the Mashpee River, Quaker Run, Shoestring I Bay, Ockway Bay, Mashpee-Wakeby Pond, Snake Pond, Santuit Pond, and Popponesset Bay proper. Because of the model construction, the model output becomes difficult to interpret as the bands tend to push up against each other. Commission and USGS staff I reviewed the model outputs to produce the final time of travel bands and subwatershed delineations (Figure 12).

I During this same time, the Town of Mashpee authorized the town Sewer Commission to proceed with a Watershed Nitrogen Management Plan, including a wastewater facilities plan. This effort included a contract with SMAST and led to an application for I funding under the State Revolving Fund. The Sewer Commission contracted with

I Cape Cod Commission 41 Final Report (June, 2002) I I I

I Figure 12. Popponesset Bay Subwatersheds I Translation of USGS Mode\ Outputs to Final Delineations I I

I >10 Upper Mashpee River I Upper I Mashpee River I I I I

Lower I Popponesset Bay

US Geological Survey Model Output Final Subwatersheds I 2-10, 20, 30, 40, 50, and >50 yr used in Nitrogen Loading Analysis Time of Travel Zones

I 1 0 1 2 Miles CoastalNitrogen Loading Project - - - CapeCod Commission,2002 I I 42 Final Repon (June. 2002) I Cape Cod Commission I I Stearns and Wheler, Inc. to complete the activities included in the SRF project application, including a nitrogen loading assessment of land use within the watershed. I Following a number of meetings among all the involved parties, it was agreed that the Commission should complete the nitrogen loading assessment that would be used in I the Watershed Nitrogen Management Plan analysis. The land use analysis protocol selected by the Town Planner involved the matching of the towns' assessors database, water use database, and, in Mashpee only, a town­ I developed impervious surface database. All of these databases would be combined and linked to the parcel information through the use of the Commission Geographic Information System (GIS). The use of water use information for determining I wastewater estimates for all parcels is a different protocol than was used for the other nitrogen loading analyses completed in this project, but the Commission previously used water use information during the nitrogen loading analyses of the Harwich I embayments during the Coastal Embayment Project (Eichner, et al., 1998b). I Three years of water use information was obtained for all parcels from the Sandwich Water District (1998-2000), the Mashpee Water District (1997-1999), and Cotuit Water District via the Barnstable DPW (1998-2000). The years of the parcel and assessors I information used in the analyses are: 2000, Barnstable and Sandwich and 2001, Mashpee. Obtaining the Mashpee parcel information caused significant delays in the analysis; initial discussions with Mashpee staff indicated that Mashpee parcel I information would be available from a town contractor in December 1999 and this information was not made available until approximately one year later. Commission GIS staff then began the time consuming task of matching all the databases and I combining the Mashpee assessors information with the new parcels. All databases I were combined and available for nitrogen loading analysis in December 2001. B. Preliminary Nitrogen Loading Analysis During the course of the Popponesset Bay analysis, SMAST and DEP were successful in I initiating the Massachusetts Estuaries Project (MEP). Because of the extensive efforts to develop water quality, tidal flushing, and watershed delineation information, as well as Mashpee' s SRF funding, Popponesset Bay was selected among the first twenty I embayments to be addressed by the MEP. The nitrogen loading being completed under the project discussed in this report will be utilized during the MEP analysis of I Popponesset Bay. Because the MEP analysis has not been completed and will involve the integration of watershed and land use information with tidal flushing and water quality information, the nitrogen loading analysis presented below should be regarded I as a preliminary analysis.

Parcels at least half in the watershed are included in the watershed unless the inclusion I (or exclusion) of the entire parcel creates a significant difference between the parcel-

I Cape Cod Commission 43 Final Report (June, 2002) I I I delineated watershed and the water table-derived watershed. Portions of parcels are added or subtracted to strive to attain a less than 2% difference between the parcel and I delineated watersheds. Commission staff reviewed the Mashpee half in/half out assignments with the Mashpee Town Planner. Nitrogen effluent concentrations and monthly flow information was used to calculate nitrogen loads from large private I wastewater treatment facilities (e.g.,Mashpee Commons). Smaller scale commercial denitrifying septic system were assigned effluent concentrations based on current DEP permit limits for the technologies utilized; residential denitrifying systems were not I accounted for in the nitrogen loads. Nonresidential properties without water use were assigned water volumes based on Title 5 factors or modified factors based on estimated employee numbers (e.g., 2.2 people/1,000 ft2 based on CCC transportation trip I estimates for industrial properties). Fertilizer application rates were obtained from each of the golf courses and green, tee, fairway, and rough areas were determined based on project staff interpretation of aerial photographs. Residential fertilizer loads I were determined based on factors in Table 3. I Table 17 presents preliminary nitrogen loading results for the 12 subwatersheds to Popponesset Bay. Existing nitrogen loads, existing nitrogen loads including estimates of private well water use, and buildout loads are presented. Existing loads vary from I 0.4 kg/ acre of watershed (Snake Pond) to 13.5 kg/ ac (Lower Mashpee River). These loads will be put into better context once they are combined with tidal flushing and I water quality data during the MEP analysis. Although the preliminary results in Table 17 are nearly complete, there are some specifics that project staff will resolve through further discussions with Mashpee, I Sandwich, and Barnstable town staff. Most of these specifics will tend to increase the presented nitrogen loads. One of the primary issues to be resolved is addressing the parcels that utilize private wells. As indicated in Table 17, between 20 and 78% of I single family residences listed in the town assessor records have no account with the respective water supplier. In Mashpee, the average single family residence used 122 gallons per day (gpd) during the three years worth of water use. This average contains I a significant number of parcels without water use: in 1997, 15% of the 3,124 accounts listed in 1999 had zero water use; in 1998, 11 % had zeros; and in 1999, 2% had zeros. I Assuming parcels using private wells have the same water use statistics as those on public water, the average water use can be applied to the parcels with private wells; this addition boosts the existing nitrogen loads (see Table 17). Falmouth, Sandwich and I Barnstable have a higher water use for single family residences within the watershed, 175, 209, and 185 gpd, respectively, with 28, 31, and 8% of the residences with public water accounts reporting zero water use. It is hypothesized that the higher seasonal I population in southern Mashpee causes the average Mashpee water use to be significantly lower than use in the other towns; MEP project team will be discussing I whether subwatershed water uses are more appropriate than town-wide averages. As

I Cape Cod Commission 44 Final Report (June, 2002) I I I mentioned above, confirmation of the nitrogen loading estimates will occur during the I MEP analyses of the Popponesset Bay system. Table 17. Preliminary Nitrogen Loads in the Popponesset Ba" Watershed Watershed SL",gleFamily Preliminary Nitrogen I Area 1 Residences 2 Load 3 Subwatershed USGS Parcel # Exist Add- Exist Exist BOw/ wo/ tion@ PW PW& Private I PW BO Private Wells Wells acres acres k"/yr kg/vr kg/vr I Upper Mashpee 2,044 2,047 545 289 485 8;559 10,264 12,911 River Upper Mashpee 572 574 76 28 62 1,502 1,667 3,131 River (> 10 yr I TOT) Lower Mashpee 1,116 1,125 453 278 89 5,809 7,466 7,826 River Lower Mashpee 293 298 52 25 64 3,962 4,109 4,946 I River (> IO yr TOT) OckwayBav 726 728 303 96 186 4,031 4,597 5,795 I Lower Popponesset 772 787 582 241 240 7,583 9,004 10,136 Bav Quaker Run 742 741 242 116 151 5,576 6,261 7,048 SantuitRiver 1,422 1,413 723 191 312 13,323 14,450 15,245 I Shoestring Bav 742 739 580 182 202 8,539 9,613 10,027 Santuit Pond 1,396 1,339 834 653 196 8,089 I 1,941 12,688 Mashpee Wakeby 4,018 3,993 1,297 382 593 20,583 22,836 27,054 I Pond Snake Pond 429 429 15 3 7 175 193 214 WHOLE SYSTEM 14,272 14,213 5,702 2,484 2,587 87,731 102,401 117,021 I PW= Public Water use info; Exist= Existing; BO= Buildout 1Subwatersheds are identified in Figure 12; USGS area based on model output area, Parcel area based on 50% in/50% out analysis and parcel splitting. I ZSingle Family Residences are parcels assigned 101 state class code; existing 101 classified parcels without an assigned account number in 1997, 1998, and 1999 are identified as "existing wo/water use". Additional single family residences at buildout are based on review of 130 and 131 parcels, as well as I existing developed residential parcels (100's in state MADOR (1991) classification system) with the potential to be further subdivided. 3Nitrogen loading estimates are preliminary; final estimates will be prepared during Massachusetts Estuaries Project analysis of Popponesset Bay. Existing N loading estimates use available water use only; I water use for parcels without a Mashpee Water District (MWD) account number are not estimated or included. Existing w /PW & Private wells assume 2% of private residences are not used and the rest use 122 gpd of water, which is average of all 101 classified parcels with MWD accounts. Buildout water use I estimates assume seasonal occupancy. MassHighway road areas were used for impervious surfaces; no additions were made based on Town of Mashpee impervious surface coverages. No attenuation in the I ponds is included in the totals. Nitrogen loading factors are same as indicated in Table 3.

I Cape Cod Commission 45 Final Report (June, 2002) I I I C. Next Stepsilliscussion/Recommendations The current Town of Mashpee Watershed Nitrogen Management Plan project will I involve analysis of nitrogen loads to both Popponesset Bay and Waquoit Bay. Portions of Waquoit Bay (Hamblin/Jehu Ponds, Quashnet River) are also listed among the first twenty estuaries to be addressed under the Massachusetts Estuaries Project (MEP). I Once the nitrogen loading assessment is completed, this information will be combined with the tidal flushing information developed by Applied Coastal Research and Engineering, Inc. and the water quality data collected by citizens under the supervision I of staff from the UMASS-Dartmouth School of Marine Science and Technology (SMAST). SMAST will then utilize the combined model to evaluate a number of nitrogen loading scenarios and the resulting nitrogen concentrations throughout the I bay. These scenarios will then be used to provide the town with a nitrogen loading limit. This limit can subsequently be used by the town engineers in the Management I Plan study as a watershed-based design limit for use in selecting wastewater treatment technologies throughout the town. I I I I I I I I I I

I Cape Cod Commission 46 Final Report (June, 2002) I I I VII. CONCLUSIONS Excessive nitrogen loading in coastal waters creates conditions that favor plants that are I incompatible with the shellfish, fish, and water quality expected on Cape Cod. Evaluating how much nitrogen loading is excessive requires a characterization of each embayment system, including an understanding of how rapidly the tides exchange the I water within various parts of the system, delineating the watersheds to the most tidally restricted sections, determining the nitrogen loads corning from land uses within the watersheds, and comparing these loads to standards associated with sustainable I nitrogen loads. This information can be compared with water quality information and incorporated into a model to produce a calibrated representation of the coastal I embayment system. This model can then be used to explore community discussions of expected water quality and willingness to fund changes in the treatment of wastewater, I which is the major source of nitrogen to these waters. This project begins the process of developing information for these types of community discussions in the watersheds to Centerville River /East Bay in Barnstable, Town I Cove/Nauset Marsh in Orleans and Eastham, Herring River in Harwich, and Popponesset Bay in Mashpee and Barnstable. These assessments are part of an overall effort by the Cape Cod Commission, the state Department of Environmental Protection, I and a number of other agencies and organizations to develop basic information for all of the coastal systems surrounding Cape Cod. The Massachusetts Estuaries Project, which has been developed by DEP and UMASS-Dartrnouth School of Marine Science I and Technology (SMAST), will take the next step forward by combining both watershed and embayment information through the use of embayment-specific models. These models will be tools for discussions of management of water quality within these I systems. The Cape Cod Commission will continue to be involved in these efforts, including assisting in the Estuaries Project by providing land use analyses similar to the results presented in this report and assisting communities with the subsequent use of I the Project findings. I The assessment of the four systems documented in this report indicate that: 1) The Centerville River/East Bay system is overloaded with nitrogen. The Town of Barnstable met this concern by committing to a citizen-based water quality I monitoring program to help to calibrate and refine the nitrogen loading analysis in this report. It is also recommended that the town consider interim steps to limit future nitrogen loading additions and preserve available undeveloped land within the I watershed for neighborhood wastewater treatment facilities. 2) Salt Pond within the Nauset Marsh/Town Cove system is the only nitrogen overloaded portion of the system. However, limited water quality assessments indicate I some nutrient sensitivity differences that should be resolved with a more comprehensive water quality monitoring project and/ or program. The Town of Orleans has recently initiated a citizen-based water quality program for the overall I system, which will lay the groundwork for a MEP analysis. Prior to collection of this

I Cape Cod Commission 47 Final Report (June, 2002) I I I inforrnation, it is recommended that the Town of Eastham and the National Park Service consider interim steps to limit future nitrogen loading within the Salt Pond I watershed. 3) A comprehensive monitoring program is also recommended for the Herring River in Harwich. Comparison of the nitrogen loading assessment to limited water I quality monitoring funded by the Cape Cod Commission suggests that denitrification of watershed nitrogen loads is occurring, but the monitoring results are too limited to be able to define an accurate range for the percentage removed. I 4) The evaluation discussed for Popponesset Bay is a portion of the next generation of embayment assessments. Under the Massachusetts Estuaries Project, land use/nitrogen loading analyses similar to those completed for the other systems in this report will be I combined with water quality and tidal flushing information into a model that will be available for Project communities to answer questions about impacts of development, I changes in wastewater treatment infrastructure, and dredging impacts. I I I I I I I I I I

I Cape Cod Commission 48 Final Report (June, 2002) I I I VIII. REFERENCES I Applied Coastal Research and Engineering, Inc. and Center for Marine Science and Technology, University of Massachusetts at Darhnouth. 2000. Ashumet Plume Nitrogen Offset Program. Tasks 1, 2, and 3. Prepared for the Town of Falmouth, MA.

I Aubrey Consulting, Inc. (AC!). 1996. Tidal Flushing within the East Bay/Centerville River Estuary: Existing Conditions and Effects of Proposed Dredging. Cataumet, MA.

I Aubrey, D.G., G. Voulgaris, W.D. Spencer, and S.P. O'Malley. 1997. Tidal Circulation and Flushing Characteristics of the Nauset Marsh System. Woods Hole Oceanographic Institution Technical Report I WHOI-97-11. Woods Hole, MA. . Cambareri, T.C., G. Belfit, D.S. Janik, P. Irvin, B. Campbell, and D. McCaffery. 1989. Truro/Provincetown Aquifer Assessment and Groundwater Protection Plan. Prepared for the towns of I Truro and Provincetown. Cape Cod Planning and Economic Development Commission, Barnstable, MA. Cambareri, T.C. and E.M. Eichner. 1998. Watershed Delineation and Ground Water Discharge to a I Coastal Embayment. GroundWater. 36(4): 626-634. Cape Cod Commission. 1996. Regional Policy Plan. Cape Cod Commission, Barnstable, MA.

Costa, J.E., B.L. Howes, D. Janik, D. Aubrey, E. Gunn, and A.E. Giblin. 1999. Managing anthropogenic I nitrogen inputs to coastal embayments: Technical basis for a management strategy adopted for Buzzards Bay. draft Buzzards Bay Project Technical Report. I Eichner, E.M. and T.C. Cambareri. 1992. Technical Bulletin 91-001: Nitrogen Loading. Cape Cod Commission, Water Resources Office, Barnstable, MA.

Eichner, E.M. and T.C. Cambareri. 1997. Watershed Analysis for the Development of Nitrogen I Management Strategies for Wellfleet Harbor. Environment CapeCod. 1(1): 22-34.

Eichner, E.M., K. Livingston, B. Smith, and V. Morrill. 1998a. Pleasant Bay Nitrogen Loading Analysis. I Cape Cod Commission, Water Resources Office, Barnstable, MA.

Eichner, E.M., T.C. Cambareri, K. Livingston, C. Lawrence, B. Smith, and G. Prahm. 1998b. The Cape I Cod Coastal Embayment Project. Cape Cod Commission, Water Resources Office, Barnstable, MA. Eichner, E.M., T.C. Cambareri, V. Morrill, B. Smith, and G. Prahm. 2000. Coastal Nitrogen Loading I Report (Interim Report). Cape Cod Commission, Water Resources Office, Barnstable, MA. Horsley & Witten, Inc. 2000. Final Report: A Baseline Hydrodynamic and Water Quality Investigation I of the Lower Herring River, Harwich, MA. Sandwich, MA. Howes, B.L. and D.D. Goehringer. 1996. Falmouth Pond Watchers: Water Quality Monitoring of Falmouth's Coastal Ponds, Results form the 1994 and 1995 Seasons. Woods Hole Oceanographic I Institution, Woods Hole, MA. Howes, B.L., P.K. Weiskel, D.D. Goehringer, and J.M. Teal. 1996. Interception of freshwater and nitrogen transport from uplands to coastal waters: the role of saltrnarshes. in Estuarineshores: evolution, I environmentsand human alterations.Edited by K.F. Nordstrom and C.T. Roman. pp. 287-310. John Wiley and Sons, Ltd.

I Cape Cod Commission 49 Final Report (June, 2002) I I I Johnson, D.G. and N.M. Davis. 1988. Water-Table Map of Brewster and Harwich, Massachusetts: I September 21 to October 22, 1987. US Geological Survey Open-File Report 88-330. Marlborough, MA Leab, M.P., T.C. Cambareri, D.J. McCaffery, E.M. Eichner, and G. Belfit. 1995. Orleans Water Table I Mapping Project, Orleans, Massachusetts. Cape Cod Commission, Barnstable, MA LeBlanc, D.R., J.H. Guswa, M.H Frimpter, and C.J. Londquist. 1986. Ground-water Resources of Cape Cod, Massachusetts. U.S. Geological Survey Hydrologic Investigations Atlas 692, 4 plates. US Geological I Survey, Marlborough, MA. Massachusetts Department of Revenue (MADOR). April, 1991. Guidelines for Classification and I Taxation of Property According to Use: Property Type Classification Codes. Masterson, J.P. and D.A. Walter. 2000. Delineation of Ground-Water Recharge Areas, Western Cape Cod, Massachusetts. US Geological Survey, Water-Resources Investigations Report 00-4000. I Marlborough, MA. National Research Council. 1993. Managing Wastewaterin CoastalUrban Areas. National Academy Press, I Washington, DC. National Research Council. 2000. CleanCoastal Waters: Understandingand Reducing the Effectsof Nutrient I Pollution. National Academy Press, Washington, DC. Nixon, S.W. 1983. Estuarine ecology-A comparative and experimental analysis using 14 estuaries and the MERL microcosms. EPA Chesapeake Program.

I Nixon, S.W., C. Oviatt,]. Frithsen, and B. Sullivan. 1986. Nutrients and productivity of estuaries and coastal marine ecosystems. Journalof the LimnologicalSociety of South Africa. 12: 43-71.

I Oldale, R.N. 1969. Seismic investigations on Cape Cod, Martha's Vineyard, and Nantucket, Massachusetts and a topographic map of the basement surface from Cape Cod Bay to the Islands. US I Geological Survey Professional Paper 650-B. Oliveira, A and AM. Baptista. 1997. Diagnostic modeling of residence times in estuaries. Water ResourcesResearch. 33(8): 1935-1946.

I Rask, S., E.M. Eichner, G. Belfi!, and T.C. Cambareri. 1994. Small Volume Well Inventory and Prioritization Project. Barnstable County, MA. Cape Cod Commission, Water Resources Office. I Barnstable, MA. Ramsey, J.S., B.L. Howes, S. Kelley, F. Li, J. Wood. 2000. Ashumet Valley Nitrogen Offset Program. Chapter 1: Evaluation of Nutrient Loadings to Great Green and Bournes Pond, Falmouth, MA, 43pp.; Chapter 2: Two-Dimensional Hydrodynamic Modeling of Great Green and Bournes Ponds, 41pp.; I Chapter 3: Water Quality Analysis of Great, Green and Bournes Ponds, 51pp. Final Technical Report to Town of Falmouth Nitrogen Offset Program and Horsely & Witten, Inc.

I Schraga, T.S. and C.T. Roman. 1997. Spatial and Temporal Variability of Water Quality in Nauset Marsh Estuary, Eastham and Orleans, Massachusetts. Technical Report NPS/NESO-RNR/NRTR/97-06. I Department of the Interior, National Park Service, New England System Support Office, Boston, MA.

I Cape Cod Commission 50 Final Report (June, 2002) I I I Teal, J.M., et al. 1983. The Coastal Impact of Ground Water Discharge: An Assessment of Anthropogenic Nitrogen Loading in Town Cove, Orleans, Massachusetts. Final Report for the Board of Selectmen. I Woods Hole Oceanographic Institution (WHO! Proposal 2778). Woods Hole, MA. United States Environmental Protection Agency and Massachusetts Executive Office of Environmental Affairs. August, 1991. Buzzards Bay Comprehensive Conservation and Management Plan. Buzzards I Bay Project, Marion, MA. Valiela, !., K. Foreman, M. LaMontagne, J. Costa, P. Peckol, B. DeMeo-Anderson, C. D' Avanzo, M. Babione, C. Sham, J. Brawley, and K. Lajtha. 1992. Couplings of Watersheds and Coastal Waters: I Sources and Consequences of Nutrient Enrichment in Waquoit Bay, Massachusetts. Estuaries. 15(4): 443- I 457. I I I I I I I I I I I

I Cape Cod Commission 51 Final Report (June, 2002) I