Open PDF File, 1.77 MB, for Final Phosphorus TMDL Report for the Lower Charles River Basin
Total Page:16
File Type:pdf, Size:1020Kb
Final – Nutrient TMDL Development for the Lower Charles River Basin, Massachusetts Final Total Maximum Daily Load for Nutrients In the Lower Charles River Basin, Massachusetts CN 301.0 Prepared by: The Massachusetts Department of Environmental Protection 627 Main Street Worcester Massachusetts & United States Environmental Protection Agency, New England Region 1 Congress Street Boston, Massachusetts With Support from: Tetra Tech, Inc. 10306 Eaton Place, Suite 340 Fairfax, VA 22030 June 2007 i Final – Nutrient TMDL Development for the Lower Charles River Basin, Massachusetts Acknowledgements This TMDL study was developed by the Massachusetts Department of Environmental Protection and the New England Region of the United Sates Environmental Protection Agency with support from Tetra Tech, Inc. in Fairfax, Virginia and Numeric Environmental Services in Beverly Farms, Massachusetts under EPA contract. A hydrodynamic and water quality model for the Lower Charles River used for this TMDL was developed by Tetra Tech, Inc. in Fairfax, Virginia and Numeric Environmental Services in Beverly Farms, Massachusetts under EPA contract. Model calibration and TMDL development were also supported by the Charles River Watershed Association through grants from the EPA and from the Massachusetts Institute of Technology. EPA Region 1 support was provided by Mr. Mark Voorhees. Completion of this study depended on the generous informational and data support from various groups. Special acknowledgement is made to the following people and groups/organizations for the development of the TMDL model and TMDL: The Model Expert Review Panel: for their expert advice, technical guidance and reviews during development of the TMDL water quality model: Dr. Steven Chapra Tufts University, Department of Civil and Environmental Engineering Dr. Ferdi Hellweger Northeastern University, Civil and Environmental Engineering Department Dr. Ken Wagner ENSR Dr. Raymond Wright University of Rhode Island, Civil Engineering Department Charles River Watershed Association: for their technical and organizational support during development of the TMDL model. CRWA convened the Expert Review Panel and organized the larger model review committee: Ms. Kathy Baskin formerly of CRWA and now of MA Executive Office of Environmental Affairs Ms. Anna Eleria CWRA Dr. Nigel Pickering CWRA Mr. Robert Zimmerman CWRA Massachusetts Department of Environmental Protection: Preparation of the TMDL Mr. Dennis Dunn Massachusetts Department of Environmental Protection Dr. Russell Isaac Massachusetts Department of Environmental Protection U.S EPA: Assisted in the preparation of the TMDL, overall funding support, and extensive water quality monitoring activities conducted in direct support for developing the TMDL model. Mr. Tom Faber United States Environmental Protection Agency, Region 1 Mr. Mike Hill United States Environmental Protection Agency, Region 1 ii Final – Nutrient TMDL Development for the Lower Charles River Basin, Massachusetts Mr. Mark Voorhees United States Environmental Protection Agency, Region 1 Mr. Bill Walshrogalski United States Environmental Protection Agency, Region 1 Others: Ms. Laura Blake formerly of New England Interstate Water Pollution Control Commission Dr. Todd Callahan Massachusetts Coastal Zone Management Dr. David Taylor Massachusetts Water Resources Authority iii Final – Nutrient TMDL Development for the Lower Charles River Basin, Massachusetts Key to Acronyms BMP – best management practice BU – Boston University BWSC – Boston Water and Sewer Commission CMR – Code of Massachusetts Regulations CRWA – Charles River Watershed Association CSO – combined sewer overflow CWA – Clean Water Act CZM – Coastal Zone Management EMC – event mean concentration EPA – Environmental Protection Agency EQIP – Environmental Quality Incentive Program IDDE – illicit discharge detection and elimination LA – load allocation MassDEP – Massachusetts Department of Environmental Protection MAWQS – Massachusetts Water Quality Standards MEP – maximum extent practicable MEPA – Massachusetts Environmental Policy Act MGD – million gallons per day MOS – margin of safety MS4 – municipal separate storm sewer system NOI – notice of intent NPDES – National Pollutant Discharge Elimination System NRCS – Natural Resources Conservation Service PI – prediction interval QAPP – Quality Assurance Project Plan SRF – State Revolving Fund SWMM – Storm Water Management Model TMDL – Total Maximum Daily Load TN – total nitrogen TP – total phosphorus UA – urbanized area USGS – United States Geological Survey WHO – World Health Organization WLA – wasteload allocation WSGP – watershed general permit WWTF – wastewater treatment facility iv Final – Nutrient TMDL Development for the Lower Charles River Basin, Massachusetts EXECUTIVE SUMMARY Section 303(d) of the Clean Water Act and the U.S. Environmental Protection Agency’s Water Quality Planning and Management Regulations (Title 40 of the Code of Federal Regulations [CFR] Part 130) require states to develop Total Maximum Daily Loads (TMDLs) for impaired waterbodies. A TMDL establishes the amount of a pollutant that a waterbody can assimilate without exceeding its water quality standard for that pollutant. TMDLs provide the scientific basis for a state to establish water quality-based controls to reduce pollution from both point and nonpoint sources to restore and maintain the quality of the state’s water resources (USEPA 1991). A TMDL for a given pollutant and waterbody is composed of the sum of individual wasteload allocations (WLAs) for point sources and load allocations (LAs) for nonpoint sources and natural background levels. In addition, the TMDL must include an implicit or explicit margin of safety (MOS) to account for the uncertainty in the relationship between pollutant loads and the quality of the receiving waterbody. The TMDL components are illustrated using the following equation: TMDL = ∑ WLAs + ∑ LAs + MOS The study area for this TMDL is the Lower Charles River, which flows through eastern Massachusetts. The river flows through 23 towns and cities and five counties. This TMDL report addresses the lower portion of the river, which is an impounded section of the Charles River referred to as the Lower Charles River in this report. The Lower Charles River is located at the downstream end of the Charles River Watershed and outlets to Boston Harbor and the Atlantic Ocean. The entire Charles River watershed drains a watershed area of 308 square miles. Two hundred and sixty-eight square miles of that watershed area drain over the Watertown Dam into the Lower Charles River. The remaining 40 square miles drain directly into the Lower Charles from small tributary streams that are mostly enclosed and piped stormwater drainage systems serving the surrounding communities. There is also a combined sewer drainage area near the downstream end of the Charles River. The Lower Charles River is in the heart of a highly urbanized area, bordered directly by the municipalities of Boston, Cambridge, Watertown, and Newton. The land uses surrounding the Lower Charles River are predominantly residential. This TMDL report addresses the nutrient and noxious aquatic plant impairments that were included on the Massachusetts Department of Environmental Protection’s (MassDEP) 2002 and 2004 section 303(d) lists (MAEOEA 2003 and 2004). The report also addresses associated water clarity impairments such as turbidity and taste, odor and color. Regular occurrences of severe algal blooms during the summer months reduce water clarity and contribute to anoxic bottom waters that do not support aquatic life. Water quality data indicate the Lower Charles River is undergoing cultural eutrophication, which is the process of producing excessive plant life because of excessive pollutant inputs from human activities. The algal v Final – Nutrient TMDL Development for the Lower Charles River Basin, Massachusetts blooms in the Lower Charles are directly responsible for degrading the aesthetic quality of the river, reducing water clarity, and impairing the designated uses. Additionally, eutrophication of the Lower Charles River has led to the occurrence of a very severe toxic algal bloom in the downstream portion of the Lower Charles during the summer of 2006. Monitoring conducted in the Lower Charles during August 2006 found cell counts of the toxic cyanobacteria (blue-green) organism, microcystes, to be so high that it caused the Massachusetts Department of Public Health to post warnings for the public and their pets to avoid contact with river. The Massachusetts Water Quality Standards identify the Lower Charles River as a Class B water that is designated to support aquatic life and recreational uses. The water quality criteria that apply to the Lower Charles River and were used to calculate the total allowable loads are presented in Table ES-1. Table ES-1. Applicable Massachusetts water quality criteria Pollutant Criteria Source Shall not be less than 5.0 mg/L in warm water fisheries unless background conditions are lower; Dissolved natural seasonal and daily variations above these 314 CMR: 4.05: Classes and Oxygen levels shall be maintained; and levels shall not be Criteria (3)(b) 1 lowered below 60 percent of saturation in warm water fisheries due to a discharge. Shall be in the range of 6.5 - 8.3 standard units and not more than 0.5 units outside of the background 314 CMR: 4.05: Classes and pH range. There shall be no change from background Criteria (3)(b) 3 conditions that would impair any use assigned