Managing Nitrogen Sensitive Embayments
Problem
Impairments to water quality and living resources caused by excessive nitrogen inputs to Buzzards Bay are one of the most pressing issues identified in this Buzzards Bay CCMP. Nitrogen total maximum daily load (TMDL) studies have not been completed for all embayments, but impairments are apparent in all the somewhat less well-flushed embayments that fringe Buzzards Bay. Loss of eelgrass beds, accumulation of benthic algae smothering shellfish beds, and low oxygen concentrations and resulting fish kills are among the impacts that must be remedied. Elimination of excessive nitrogen loads will ensure that all designated uses for those embayments are met[1]. Wastewater discharges are typically the largest source in most watersheds. While state and federal agencies regulate permitted discharges like outfall pipes, some sources of pollution like cumulative loadings from septic systems are difficult to regulate. Solutions typically focus on municipal sewer expansion or nitrogen removing onsite systems, both of which have high costs.
[1] Unless additional impairments are caused by other pollutants. “Designated Uses” are those listed in Massachusetts Water Quality Standards.
Goals and Objectives
Changes: The goals and objectives were re-worded improve clarity and readability and to include climate objectives. Nine new objectives were added to clarify the scope of actions needed to meet the stated goals and to reflect new state laws and policies.
Goal 1.1. Prevent the loss of designated uses and reduce adverse impacts to Buzzards Bay ecosystems due to excessive contributions of nitrogen.
Goal 1.2. Restore lost designated uses and adversely affected ecosystems impaired by the excessive contribution of nitrogen to any area within Buzzards Bay.
Objective 1.1. By 2030, adopt watershed nitrogen total maximum daily load limits for all impaired Buzzards Bay embayments. Ensure these limits include a margin of safety calculation for climate stressors like temperature, precipitation, and acidification that may exacerbate coastal eutrophication.
Objective 1.2. Reduce nitrogen loads to nitrogen-impacted embayments to meet approved watershed nitrogen loading limits and waste load allocations.
Objective 1.3. Ensure new additions of nitrogen to coastal waters do not cause, or contribute to, a violation of state surface water quality standards, or exceed federally approved total maximum daily loads.
Objective 1.4. Ensure that state and federal discharge permits set limits that meet nitrogen loading limits and waste load allocations specified in approved total maximum daily load limits.
Objective 1.5. Promote the development and implementation of local TMDL implementation plans to manage nitrogen sources to meet total maximum daily load limits and waste load allocations.
Objective 1.6. Promote the development of and use of alternative and advanced nitrogen reducing wastewater treatment technologies at all scales of flow.
Objective 1.7. Monitor water quality and natural resources (e.g. eelgrass beds, algae, dissolved oxygen), at a sufficient frequency to document management needs, assess the effectiveness of actions taken, and to document ongoing changes and variability in water quality and ecosystems health.
Objective 1.8. Support studies that advance the understanding of the relationship between changing water temperature and precipitation patterns on forms and amounts of nitrogen conveyed to coastal waters and how the changes may affect achieving total maximum daily load limits. (New)
Objective 1.9. Collect and analyze water temperature and nutrient levels in embayments, the Cape Cod Canal, and central portions of Buzzards Bay. (New)
Objective 1.10. Collect and analyze stream temperature, flow, and nutrient loads to better characterize climate driven impacts. (New)
Objective 1.11. Collect and analyze stormwater samples nutrient load reductions. (New)
Objective 1.12. Support development of improved groundwater flow and nutrient loading models, including those that account for climate change impacts. (New)
Objective 1.14. Support Buzzards Bay municipal efforts to adopt and implement watershed permits, watershed management plans, and comprehensive wastewater management plans to reduce nitrogen loading to state designated Nitrogen Sensitive Areas and other impaired waters. (New)
Objective 1.15. Support studies that advance the understanding of nitrogen cycling in sediments of state-designated Nitrogen Sensitive Embayments. (New)
Objective 1.16. Encourage adaptive management and performance checkpoints in watershed management planning to continue reducing nitrogen loading to state designated Nitrogen Sensitive Areas. (New)
Objective 1.17. DEP and EPA should ensure that all surface water discharge permits support total maximum daily loads waste load allocations and watershed permit goals. (New)