3 DREDGED MATERIAL EVALUATION PROCESS

Transcription

1 3 DREDGED MATERIAL EVALUATION PROCESS The main questions that the DMMP evaluates are: 1. Is proposed dredged material suitable for? Open-water disposal can be at one of the designated DMMP sites or in some cases in flowlane disposal areas. 2. Is proposed dredged material suitable for in-water beneficial use? In general, material proposed for beneficial use needs to not only meet DMMP guidelines for open-water disposal, but must also meet Washington State Sediment Management Standards requirements as well. Fisheries agencies or landowners/managers may require more stringent comparisons, especially with in-water beneficial reuse or habitat creation projects. 3. Will the post-dredge surface meet Washington State anti-degradation standards when the project is finished? In other words, will the sediment surface left behind after dredging be degraded relative to the sediment surface that existed prior to dredging? This question is often the only applicable question for DMMP consideration if the proposed disposal site is upland with no return water. To answer these questions, the DMMP uses a tiered approach to sediment characterization. There are four tiers of evaluation: Tier 1: Site Evaluation and History Tier 2: Chemical Testing Tier 3: Biological Testing (bioassay and or bioaccumulation testing) Tier 4: Special Studies Every project is subject to a Tier 1 evaluation, which is a review of historical and ongoing sources of contamination, land use, and any previously collected data (Chapter 4). Occasionally a suitability determination can be made using only Tier 1 information. For other projects, Tier 1 informs the characterization required in subsequent tiers. Tier 3 biological testing is invoked if chemicals of concern are present at concentrations that are of potential concern for human health or the environment. Time can be saved by compressing Tiers 2 and 3-- that is, by conducting concurrent chemical and biological testing. Tier 4 testing is rarely required by the agencies or pursued by dredging proponents. If Tier 4 testing is needed, it is specially designed in coordination with the DMMP agencies. It is always the project proponent s decision whether to proceed to the next tier for further testing; the option of disposing of material upland rather than pursuing further testing is always available. The dredged material evaluation process is required for every dredging cycle. In some cases this will be as simple as checking to see if an existing suitability determination covers the proposed dredging, as might be the case for frequent, routine maintenance dredging. In other cases, it will require Tier 2 and 3 testing. Regardless of the project, DMMP coordination needs to be conducted and a decision for that dredging cycle documented. The dredged material evaluation process consists of the following steps (Figure 3-1): 1. Dredging proponent (with consultant assistance as needed) determines project-specific sampling and analysis requirements, as stipulated in this User Manual. DMMO may be contacted for assistance. DMMP User Manual 3-7 August 2016

2 2. Dredging proponent develops a sampling and analysis plan (SAP) for sediment evaluation (Chapters 5 & 6). 3. Dredging proponent submits SAP to the DMMO. 4. DMMO coordinates review of the SAP by the other DMMP agencies. Proponent may be required to address concerns and re-submit the SAP if it does not meet DMMP requirements. 5. DMMO sends a SAP approval letter or message to the dredging proponent. 6. A pre-sampling conference call between the DMMP and sampling team may be scheduled prior to the beginning of sampling. 7. Dredging proponent conducts field sampling and laboratory testing. 8. Dredging proponent submits a sediment characterization report to the DMMO for distribution to all DMMP agencies. 9. DMMO coordinates review of the testing data with the DMMP agencies. Proponent may be required to address concerns and re-submit the sediment characterization report if it does not meet DMMP requirements. 10. DMMO drafts and the agencies review and sign a suitability determination for disposal. Figure 3-2 and Figure 3-3 summarize the tiered approach for marine and freshwater sediments, respectively. DEBRIS MANAGEMENT A debris management plan is required for all projects, and should be considered as part of the Tier 1 Evaluation. See Chapter 13 for information on debris management in the DMMP. DMMP User Manual 3-8 August 2016

3 Applicant DMMP Determine sampling and analysis requirements (Chapter 4) Develop sampling and analysis plan (SAP) Submit SAP to DMMO DMMO coordinates SAP review by regulatory agencies Do not proceed to sampling without DMMP approval of your SAP Field sampling and laboratory testing DMMO sends SAP approval letter or Submit final report along with EIM data and comprehensive laboratory data package (Chapter 10) DMMO coordinates data review with regulatory agencies and prepares decision document Decision document signed and distributed Figure 3-1. Dredged Material Evaluation Process DMMP User Manual 3-9 August 2016

4 TIER 1 Assess existing sediment data TIER 2 Chemical testing Any BTs exceeded? Are all chemicals below SL? Do dioxin and/or TBT meet DMMP guideline values? Biological testing: Bioaccumulation tests for compounds exceeding BT Biological testing: Bioassay compounds over SL TIER 4 Special Studies Material is UNSUITABLE for Material is SUITABLE for Figure 3-2. Tiered Testing Decision Diagram for Marine Sediment DMMP User Manual 3-10 August 2016

5 TIER 1 Assess existing sediment data TIER 2 Chemical testing Are all chemicals below SL1? Biological testing: Bioassays for compounds over SL1. Bioaccumulation tests for compounds on a case-by-case basis. TIER 4 Special Studies Material is UNSUITABLE for Material is SUITABLE for Figure 3-3. Tiered Testing Decision Diagram for Freshwater Sediment DMMP User Manual 3-11 August 2016