Non-Federal Dredge (NFD) Location Sub-group Meeting Notes -
DRAFT
September 16, 2014, 2:00, City Hall, Law Library Introduction: The NFD operates on the assumption that private and municipal berths and anchorages in Portland Harbor (Portland and South Portland) require dredging of approximately 400,000 cy of dredge spoils not suited for at-sea disposal. A Confined Aqueous Disposal (CAD) cell has been accepted by the NFD as the only environmentally, financially, and socially acceptable solution for disposal of contaminated material. The Location sub-group was formed to make a recommendation to the full NFD on a prioritized CAD cell site for further evaluation. The Sub-group met on September 16, 2014 and was represented by Charlie Poole, Glen Daukas, Richard Ingalls, Dan Haley, and Frank Strout. Bill Needelman facilitated and took notes. Sites considered: The sub-group first explored criteria for prioritizing between three previously discussed sites: Site 1: Turning Basin in the Fore River Site 2: Fish Point, South of Fort Allen Park at the head of the harbor Site 3: Halfway Rock, West of Great Diamond Island and east of Mackworth Island, west of the Cousins Island channel The above sites have been discussed by the full NFD Workgroup for some months and appear to be the most viable options. Each site has challenges.
Site #3
Site #2
Site #1
NOAA “Portland Harbor and Vicinity “ Chart Excerpt 1
Google Earth Images, 2014
Site #1
Site #2
Site #3
Criteria: Following a general conversation regarding the sites at the beginning of the meeting, the Subgroup listed un-weighted criteria for consideration: 1. Technical feasibility - Can a CAD cell be constructed at the site? While listed as an un-weighted criterion, this is in reality a threshold test. When applied to the three sites, the Sub-group considered water depth - whether or not there was adequate depth to reasonably operate the equipment needed to construct the site. Another feasibility test, depth to subsurface resistance (bed rock,) was not evaluated due to lack of information. All parties understood that subsurface profiling could eliminate a prioritized site if inadequate or inappropriate sediments are discovered. 2. Toxicity of the overburden sediments – The Subgroup understood that the recent (postindustrial) sediments at all three localities likely contain contaminants that will complicate and add cost to the permitting, construction, and disposal of material excavated in creating a CAD cell. Without comparative sediment contamination data, the Subgroup did not use this criterion in prioritizing sites, understanding that full sediment testing would be needed for the permitting of the CAD. It is conceivable that sediment toxicity testing results of a prioritized site may warrant reevaluation of its suitability. 3. Navigational impacts – The Subgroup used location in, or impacts to a federal channel as the measure of this criterion. Other impacts, such as the existence of moorings and recreational use of the watersheet were considered with the understanding that such uses can be relocated if needed. 4. Fisheries impacts – The Subgroup relied on Mr. Strout’s experience lobstering in Portland Harbor to evaluate fisheries impacts related to the three potential sites. While some scallop dragging occurs in proximity to the sites, Mr. Strout was not aware of active harvesting of any species other than lobster on the sites themselves. The seasonality of both the lobstering effort (largely warmer months in these areas) and dredging (restricted to colder months by permitting requirements) were discussed and considered. 5. Harbor bottom ecology – Related to the fisheries impacts noted above, benthic ecology will play a role in the final selection and permitting of a CAD cell site. For the purposes of the Subgroup’s work, the existence of lobster (as reflected by fishing effort) was used as an indicator of harbor bottom ecological activity. The Subgroup recognized the limitation of the assumption that fishing effort reflects benthic ecology value, but in the absence other information to evaluate, they relied on criterion 4 above 2
as a substitute for unknown conditions. This assumption recognizes that further study and observation will be needed to evaluate issues such as eel grass beds and critical habitat for other species as part of the permitting process. 6. Tidal flow and current conditions – Strong currents are expected to complicate the control of sediments entering a CAD cell and potentially increase sediments entering the cell during its operational life, impacting its capacity. None of the sites evaluated were anticipated to be negatively impacted by strong currents, but this assumption will need to be confirmed. 7. Water quality ratings – Feedback from NFD participant from the Maine DEP have indicated reluctance to consider CAD cell sites that are located in areas of better water quality than the dredge localities contributing sediments. It is assumed that the two “inner” harbor sites are rated at a lower quality than site 3 located further out in the bay. Confirmation of this assumption and confirmation that the distinction would result in increased permitting barriers for site 3 will need to be established by DEP. 8. Public Opinion – Whichever site is selected for further evaluation will need to be vetted by both a permitting process and a public education/involvement process. The Subgroup used proximity to residential neighbors as an indicator of public interest in potential sites, understanding that other constituency groups will have legitimate interest in site selection moving forward. 9. Efficient Operation – Criterion 1 above addresses the feasibility of constructing a CAD cell. The issue of water depth will also impact the efficient operation of the cell if full tide access is not available. Additionally, sites closer to the assumed dredge projects will minimize transportation costs. Scoring: The Subgroup used the above criteria to score the three sites. Each criteria was evaluated and weighted equally. Given that certain criteria may warrant greater consideration that others, the scoring results should be considered a first pass evaluation pending further discussion by the full NFD Workgroup. Furthermore, as additional information comes to light the scoring of a site could change significantly. Additional information that the Workgroup may collect includes: the impact of water depth on CAD cell construction; the extent and impact of recent sediment contamination on CAD cell permitting and construction costs; potential tidal flow/current impacts; harbor bottom ecology; and, subsurface sediment profiling. Cost: The subgroup did not differentiate between sites based on cost. While limited cost information was provided by email to the Subgroup on sites #1 and #2, the contractor providing the information cautioned against consideration of site #3 due to water depth limits. The Subgroup had questions as to the extent of cost implications related to water depth at site #3 given the charted depth at low tide being greater than 15 feet in many areas. For the purposes of this evaluation, CAD cell construction costs between the sites were considered equal, subject to further evaluation. Scoring: Using the criteria established, the Subgroup assigned a consensus rating to each site for each criterion. Criteria for which there was no information (overburden toxicity) or no apparent distinction (tidal influence) were not scored. Unscored criteria were left in the evaluation matrix to indicate that future information on these issues may influence the results during subsequent evaluations.
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Portland Harbor CAD Location Scoring Matrix - DRAFT Scoring: 0 = Fail
1 = Poor
Criteria 1. Technical feasibility (CAD construction)
2 = Fair
3 = Good/Excellent
Site #1, Turning Basin 1
Site #2, Fish Point 3
Site #3, “Halfway Rock” 2
2. Toxicity of overburden (recent sediments)
Not enough data (assumed equivalent for the purpose of siting evaluation)
Not enough data (assumed equivalent for the purpose of siting evaluation)
Need confirmation that water depth limits operations Not enough data (assumed equivalent for the purpose of siting evaluation)
3. Navigational impacts (Federal Channel, moorage…) 4. Fisheries impacts (using lobster fishing effort as the measure) 5. Harbor bottom ecology (referring to Criterion 4 pending additional information) 6. Tidal/current influence
1
3
3
Note: Relocation of +/-7 Moorings needed
3
2
3
3
2
3
Assumed equivalent pending further exploration
Assumed equivalent pending further exploration
Assumed equivalent pending further exploration
7. Water Quality (DEP rating)
3
3
1
Need confirmation of rating from DEP
Need confirmation of rating from DEP
Need confirmation of rating from DEP
8. Public opinion (proximity to residential uses) 9. Operational efficiency (during use of the CAD)
3
1
2
1
3
1
Scoring
15
Need confirmation that water depth limits operations
17
15
Draft Results: Based on the information available, site #2 scored the highest (17 points) with sites #1 and #3 tied closely behind (15 point.) Using the seven scored criteria, there were a total of 21 points available. Respectfully submitted Bill Needelman City of Portland Waterfront Coordinator 9-18-14
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