Water body(s): List the water body(s) that the TMDL applies to (for example, Walker Creek, or all Bay segments).
Stressor(s): List the stressor(s) that the TMDL applies to (for example, Mercury, or copper and nickel).
General Approach: Each workplan should start with a General Approach element within which we explain the gist of the workplan and justify the approach proposed. For example, in this element we may call attention to our intent to focus on stakeholder involvement and their commitment to an implementation plan first, before expending resources on calculation of a TMDL. We should state what our top priority(s) are in this element, and the order in which each of the template elements will be implemented.
Problem Statement: Written description of which standards are not being attained, which beneficial uses are impaired, and the nature of the impairment. Identify outstanding issues that need resolution to proceed. For example, basis of impairment is qualitative and need quantitative end point such as a numeric water quality objective, or basis of listing has significant uncertainty. Note if possible outcome may be de-listing.
Numeric Targets: The Desired Future Condition: Written discussion of measurements that will describe protection of the beneficial uses that are impaired, and attainment of standards, such as the actual Total Maximum Daily Load of a pollutant that the water body can assimilate. Numeric targets may not be directly enforceable but are used to assess progress towards, or attainment of standards. Identify approach to be taken (eg, use of a model) and outstanding issues that need resolution to proceed (eg, insufficient data currently available). As appropriate, include the need for a linkage analysis that describes how the Numeric Targets relate to the Problem and how the required margin of safety will be incorporated into the TMDL. The margin of safety may be implicit, i.e., using conservative assumptions, or explicit, i.e., a discrete allocation assigned to the margin of safety.
Source Analysis: Written report that identifies the amount, timing, and point of origin of pollutants of concern. May be based on field measurements and/or models and estimations. Note whether sources are ongoing and/or historical, natural or human caused. Identify outstanding issues that need resolution to proceed (eg, insufficient data currently available).
Allocations: Allocations of responsibility identify who is to take the specified actions. May be specific to agencies or persons (businesses) or generally by source category or sector. Allocations of allowable pollutant burdens define TMDL endpoints (e.g., total sediment load from urban runoff). Sum of individual allocations must equal total allowable pollutant burden.
Implementation Plan: Describes what is to be done, what actions will be undertaken to alleviate the impairments. Identifies enforceable features (e.g. prohibition), triggers for Regional Board action (e.g. performance standards). May be part of a watershed management plan.
Monitoring/ Revaluation: For phased (adaptive management) TMDLs, a description of the monitoring strategy that will be used to develop more refined information for performance evaluation and consideration of TMDL revisions.
Basin Plan Amendment: Include actions relevant to Regional Board consideration of a Basin Plan Amendment to adopt the TMDL (and all its related parts). Consider: official notice for CEQA purposes and announcement to the public of Regional Board consideration of the proposed TMDL and response to comments.
SAN FRANCISCO BAY - MERCURY TMDL WORKPLAN
DRAFT - TASKS, TIMEFRAMES, AND RESOURCES ARE DEPENDENT ON AVAILABILITY OF RESOURCES AND STAKEHOLDER SUPPORT (This draft is same as version under review by the Mercury Council; only minor format changes have been made.)
Water Body: All San Francisco Bay Segments
Our general approach is to establish and maintain environmental conditions that will, over time, result in the attainment of water quality standards. The two main factors that need to be controlled to achieve this goal are the overall mass balance of mercury in the Bay system and the extent to which this stock is transformed into bioavailable mercury. Current scientific knowledge is not advanced enough to develop quantitative predictions of how much loading must be controlled in conjunction with practical management of biotransformation to achieve quantified changes in fish tissue concentrations. In other words, ongoing loads could be reduced to zero but not affect tissue levels if biotransformation is not managed to the extent practical. The converse is also true. To address this uncertainty, we are developing a conservative, protective approach that will achieve the best mass balance possible (accelerating cleanup of Gold Rush legacy stocks) and manage biotransformation to the greatest extent practicable. Together, these will ensure that standards are eventually attained and in the shortest possible time.
The technical approach outlined above will be developed in a region-specific regulatory program. This program will serve as the first phase of a TMDL and includes:
a thorough technical review and characterization of sources;
establishment of policies for allocating loads/ wasteloads amongst source classes;
development of implementation measures and tools for source classes based on the allocation policies;
scientific peer and stakeholder review of conceptual models linking mass loading and biotransformation to numerical targets;
prioritization of technical information needs and initiation of critical research; and
implementation of the allocation policies to the extent possible before the TMDL is finalized (i.e. for classes of sources judged to be insignificant).
The second phase of the TMDL will include review and refinement of water quality objectives, establishment of a formal numerical target for a TMDL, and oversight of the research efforts. The TMDL will be completed in the third phase through development of a model linking loads to bioaccumulation, stakeholder review and refinement of allocations, and formal Basin Plan adoption of all pieces not previously incorporated.
Approach: Develop a region-specific regulatory program that will result in the attainment of water quality standards by:
reviewing and revising standards as appropriate;
identifying the relationship between standards and loading, natural bioaccumulation processes, anthropogenic enhancements to loads, and anthropogenic enrichment of bioaccumulation processes;
developing TMDL elements to address loading effects;
developing management techniques to address bioaccumulation processes;
adopting Basin Plan changes and implementing the first phase of the regulatory program
completing the TMDL by allocating necessary reductions in loads amongst classes of sources of ongoing mercury inputs
developing and adopting any additional Basin Plan changes necessary to ensure that loads and bioaccumulation processes are managed to the extent necessary to attain water quality standards
Mercury listing is based on consistent health advisories for several species of sport fish due to mercury and frequent exceedance of numeric water column objectives in the Basin Plan (total).
Regional Monitoring Program data on water column and fish tissue levels consistently indicate that levels of mercury in the Bay system are above thresholds of concern. Reconnaissance-level monitoring data on wildlife exposure (clapper rail) and methyl mercury concentrations in water also suggest a cause for concern.
Historic scientific studies indicate that the vast majority of mercury in the Bay and watershed system is the legacy of the Gold Rush era; ongoing loads are small in comparison to existing sediment stocks.
A technical review of how mercury affects beneficial uses, the extent and nature of mercury in the Bay aquatic environment, sources, loadings, and historic contamination has been completed.
Additional Work Needed:
There are two types of additional work needed to refine our understanding of the mercury bioaccumulation problem. The first involves updating the Basin Plan objective; this will serve as the basis for the numeric target. The second involves additional research to identify where and how mercury is being transformed into the bioavailable form; this information will be used to develop and require management of this process to the extent practicable.
While there is a general consensus that mercury levels in the Bay system are high, the existing water quality objectives need to be updated to reflect our improved understanding of, mercury levels, sources, and bioaccumulation. The objective is currently expressed as total mercury in a water sample; technical analyses have demonstrated that total mercury is a direct function of suspended sediment levels and is thus not a direct indicator of changes in mercury levels in the Bay system. In addition, the current objective is also based on outdated assumptions about human health risk (it was derived using the 1.0-PPM FDA action level) and does not incorporate protections for wildlife.
These issues can be resolved by refining the existing Basin Plan water quality objective. Our intent is to develop a site-specific objective for chronic toxicity, expressed as a dissolved water column concentration, and a site-specific objective for bioaccumulation, expressed as dose-tissue concentration limits for humans and wildlife.
While the levels of total mercury throughout the Bay system are generally well-characterized, additional technical information on precisely where and how mercury present in the system becomes a bioaccumulation problem is needed to ensure that mass loading controls will result in attainment of standards. Information on sediment and particle-bound mercury, the occurrence and concentration of methyl mercury, and mercury fluxes between marshes and shallow areas and the main body of the Bay are needed.
Develop site-specific objectivea for chronic toxicity
Develop ssoa for bioaccumulation
Revise comparison to background tissue levels
Identify Bay subenvironments where methylation is taking place, timing and extent of methylation, identification of causal processes, and preliminary identification of potential management techniques
Characterize sediment particles in Bay and those from major riverine and stormdrain inputs, identify enrichment
Develop estimates of flux between marshes and Bay at four characteristic Bay margin sites
TMDL product: 303(d) listing review and refinement, establishing numeric objectives to serve as basis for numeric target, characterization of how loads affect bioaccumulation in relation to other factors.
Numeric Targets: The Desired Future Condition:
We are defining the desired future condition as:
Condition 1: Ongoing mass inputs of mercury are significantly less than the natural rate of removal/ burial of mercury in Bay sediments, and Condition 2: There is no significant human enhancement of natural mercury transformation processes and, to the extent practicable, mercury fluxes into areas where transformation occurs is actively controlled.
Meeting Condition 1 will ensure the appropriate mass balance in the Bay system. This in turn will eventually result in limiting the amount of mercury subject to transformation and bioaccumulation. Assuming no changes in transformation rates, this will result in lower tissue concentrations and the attainment of water quality standards. Thus, the numeric target for a mass-based mercury TMDL will be defined in terms of the total reductions in ongoing mercury loads necessary to achieve the desired mass balance.
Condition 2 will be addressed in the regional regulatory policy and program for mercury discussed in the other tasks. The technical information needed to achieve this condition is described in the Problem Statement Task.
A general mass balance model for the northern Bay segments has been developed and reviewed by stakeholders and scientists.
Additional Work Needed:
The geographic scope of the current mass balance needs to be extended to the southern embayments and refinements made to loading estimates from classes of sources.
Expand and revise existing mass balance to cover entire Bay
Stakeholder review and involvement in definition of acceptable level of certainty in mass balance
Establish required mass reductions in ongoing mercury loads (numeric target)
Current data indicate that most of the mercury flowing into the food chain probably comes from legacy sources. Of the ongoing mass inputs, contributions from the Sacramento and San Joaquin Rivers, stormwater, and nonpoint runoff (including atmospheric deposition onto land) are responsible for a large fraction of current inputs. Industrial and POTW treatment plants and direct air borne deposition to water account for a relatively small fraction of ongoing inputs.
Ongoing mass inputs of mercury to the Bay system and the chemical characteristics of these inputs have been characterized to varying degrees of certainty. Additional certainty is needed regarding loads and chemical characteristics of stormwater additions, accurate loading data from most treatment plants, and loads and chemical characteristics of fluxes from selected watershed drainages is required. Permitees have been asked to provide most of this information. Quantification of fluxes from selected local watersheds will be developed as part of broader, collective monitoring efforts.
An economic analysis of treatment/ remediation costs for general control measures for each class of source has been completed. The analysis was used to prioritize potential control measures through the watershed.
Additional Work Needed:
Characterization of sources in terms of relative bioaccumulation impact
TMDL products: characterization of sources and loadings, development of potential implementation measures, and development of information needed to support allocation policies.
Linking Loads and Management Practices to the Attainment of Standards: Work Needed:
Integrate mass balance model and information derived from research work described in Problem Statement and Source Analysis tasks
Quantify required reduction in ongoing mass loading and classify according to type of mercury
TMDL product: quantified load reduction (TMDL)
Allocations and Implementation Measures:
This task will be completed in two phases. In the first phase, existing information will be used to develop policies for allocating any reductions in loads amongst classes of sources that may be necessary. Measures to implement these policies for classes of sources will also be developed in the first phase, and to the extent possible, implemented Both of these tasks must be coordinated with Region 5 and provide for considerable stakeholder review and involvement.
After the technical and loading information needs described in the Problem Statement task and Source Analysis tasks have been filled, the remaining load and wasteload allocations will be defined, again with considerable stakeholder review and participation.
A draft allocation policy and implementation measure for treatment plants and general implementation provisions for stormwater sources has been developed and reviewed by stakeholders. Staff are currently working to coordinate Region 5’s mercury strategy with this Region’s allocation policy development.
In addition, a draft mass offset program designed to direct regulation towards the most cost-effective ongoing mercury sources has been proposed.
Additional Work Needed (phase 1):
Revise and refine draft allocation policies and Basin Plan language describing implementation measures
Coordinate allocation policies and cleanup priorities with Region 5
Draft provisions for pilot mass offset
Revise Board package for Basin Plan adoption
Additional Work Needed (phase 2)
Implement and manage pilot offset program
Establish and run stakeholder process to assign responsibility for required load reductions, define appropriate management of natural bioaccumulation processes
Develop specific implementation measures for remaining classes of sources
Revise Board package for Basin Plan adoption
please note that we anticipate that this phase will focus on allocating loads to stormwater, nonpoint, and Sacramento watershed sources and that the process will be extremely contentious
TMDL products: completed load and wasteload allocations, complete implementation measures and tools for all classes of sources
There will be three ongoing monitoring needs after the completion of the full TMDL: fish tissue sampling to track progress towards attainment, methylation site monitoring to track the success of management efforts, and measuring the success of cleanup activities.
Additional Work Needed:
Evaluate effectiveness of methylation management techniques
Evaluate source remediation effectiveness and refine pilot offset program if necessary
Basin Planning Process:
This section describes the additional work required to adopt the regulatory provisions developed in the course of completing all of the tasks outlined above--i.e. all stakeholder negotiations and technical documentation are completed in the other tasks.
Additional Work Needed:
Establish document management system for administrative record and public access
FY1999/00 1/4 PY
Prepare package for Regional Board consideration (CEQA documentation, documentation of stakeholder processes and comments, responses to comments, peer review, notice of filing, etc.)