The Maine Coastal Mapping Initiative (MCMI) uses state-of-the-art technology to collect hydrographic quality bathymetry and information about seafloor sediment. We further investigate the seafloor environment using underwater video and collecting a sample to catalogue benthic species.
Seafloor Sediment Investigations and Sand Budgets
Technical Report
Peter Slovinsky, Maine Geological Survey, December 2020
Summary: The Maine Geological Survey, Maine Coastal Program, and Nearview LLC completed topographic and volumetric change detection analyses on at three Maine beaches following onshore or nearshore beach sand replenishment using the combined data from unmanned aerial surveys, single-beam echosounder, and multi-beam echosounder. This report analyzes the change at each beach from the topographic high tide extent to the theoretical depth of closure.
Bathymetric Change and Sand Dynamics in the Kennebec River and Offshore Popham Beach, pdf, 15.1 MB
Technical Report
Stephen M. Dickson, Maine Geological Survey, and Benjamin Kraun, Maine Coastal Program, December 2020
Summary: This work focused on the Kennebec River sand budget to better understand its role in the creation and preservation of beaches. Multibeam surveys of the Kennebec River collected backscatter and bathymetry in 2017 and 2019. Three sections or reaches of the river were analyzed for change detection to quantify a 2-year sediment budget. Around 85% of the area studied underwent riverbed elevations change in excess of 10 centimeters vertically. The analysis indicated a net gain of 1.3 million (+/- 0.5 million) cubic meters of sand over two years from the study area. There are no large sedimentary depositional environments within the Kennebec River channel that can accommodate such a large volume of sediment. Therefore, volume loss most likely represents beach sand export to the ocean.
Technical Report
Kerby Dobbs, Maine Coastal Program
April 2017
Summary: Seafloor sediment textural maps were generated using a supervised classification technique based on bathymetry and backscatter data, 1st-order bathymetric derivatives, and grab sample data as inputs. The accuracy of textural output maps was evaluated using sediment samples and bottom videos. The accuracy of model output and its ability to produce areal distribution of sediment types and corresponding depths consistent with general interpretations of seafloor sediment distribution and morphology in the coverage area suggest this is an efficient and effective method for mapping seafloor substrate. Two models identified areas of fine sand with an 80% accuracy. Overall, the products of this investigation are most useful for visualizing spatial trends in sediment and benthic habitat distribution and identifying and/or refining knowledge of resource (abiotic and biotic) potential.
Preliminary Sand and Gravel Reservoirs Assessment for Federal Waters: Mid-coast Maine, pdf, 5.44 MB
Technical Report
Kerby Dobbs, Maine Coastal Program
February 2017
Summary: Following Hurricane Sandy, the Bureau of Ocean Energy Management recognized the need to identify additional outer continental shelf sand resources for beach nourishment and coastal restoration projects because sand resources in state waters are either diminishing or are of poor quality, or otherwise unavailable. In this investigation, the MCMI combined new and pre-existing geological and geophysical data to characterize and estimate volume for potential sediment resources in waters of federal jurisdiction within Maine’s mid-coast region.
Results identified 6 distinct zones containing potential sand and gravel resources within federal waters, with a combined total volume of approximately 32 million cubic meters (42 million cubic yards). Overall, this investigation highlights the need for more comprehensive assessment and management of additional potential resources (e.g. shoreface/nearshore deposits) for beach nourishment and coastal restoration efforts within the region.
2017 Seafloor Sediment Sampling: Southport Island to Monhegan Island, Gulf of Maine, pdf, 8 MB
Technical Report
Kerby Dobbs, Maine Coastal Program
November 2017
Summary: The purpose of this investigation was to collect seafloor substrate data within the 2017 focus area and combined with existing data will help accomplish the following objectives: benthic habitat classification, modeling and mapping via the federally-approved Coastal and Marine Ecological Classification Standard, generation of generalized seafloor sediment maps, build upon existing knowledge of local and regional geologic framework, and assess potential sand and gravel reservoirs. This report presents summarized bottom sample (69 sites) data collected by the MCMI during the 2017 field season (April to September), generalized descriptions of sand and gravel deposits, and preliminary sediment mapping of the approximately 125 mi2 (325 km2) survey area offshore of midcoast Maine between Southport Island and Monhegan Island.
2016 Seafloor Sediment Analysis and Mapping: Mid-coast Maine, pdf, 27.7 MB
Technical Report
Kerby Dobbs, Maine Coastal Program
February 2017
Summary: The purpose of this investigation was to collect additional seafloor substrate data within the 2015/2016 focus area, which when combined with existing data has helped accomplish the following objectives: perform benthic habitat classification, modeling and mapping via the federally-approved Coastal and Marine Ecological Classification Standard, generate seafloor sediment maps using advanced GIS techniques, and conduct volumetric assessment of potential sand and gravel reservoirs within federal waters. The data presented in this report represent the seafloor sampling efforts and sediment analyses conducted by the MCMI during the 2016 field season (April to October), which included bathymetric mapping for approximately 57 mi2 (148 km2) of seafloor and the collection of bottom samples in 54 locations, 43 in state water and 11 in federal waters, in the vicinity of the Kennebec River paleodelta.
2015 Seafloor Sediment Analysis and Mapping - Midcoast Maine, pdf, 18.8 MB
Technical Report
Kerby Dobbs, Maine Coastal Program
January 2016
Summary: The collection and analysis of geophysical and seafloor sediment data allow state and federal agencies to proactively identify the resources available to enhance resiliency, improve management of resources within their jurisdiction, and develop a more comprehensive understanding of potential resources. During the 2015 survey season MCMI mapped approximately 80 mi2 (207 km2) of seafloor and collected bottom samples in 61 locations, 43 in state water and 18 in federal waters, in the vicinity of the Kennebec River paleodelta. Grain-size analyses of sediment samples combined with interpretations of backscatter intensity and bathymetric data are consistent with general interpretations of seafloor sediment distribution and morphology in the region. Within the survey area, laterally extensive surficial deposits of predominantly sandy and/or gravelly material were restricted to depths less than 70 m and were most commonly associated with the Kennebec river paleodelta/nearshore ramp. Similarly, backscatter and grab sample data suggest these deposits were even more scarce within federal waters of the survey area.
2014 Seafloor Sediment Analysis and Mapping - Southern Maine, pdf, 22.2 MB
Technical Report
Kerby Dobbs, Maine Coastal Program
January 2016
Summary: In 2014, the Maine Coastal Mapping Initiative collected 28 sediment samples in the federal portion of the focus area located offshore of Kennebunkport in Southern Maine, though 49 additional samples were collected nearer to shore. Samples were processed to determine the relative concentrations of gravel, sand, and mud (Folk 1954), and the sand fraction was further analyzed to determine the degree of sorting and the distribution of grain sizes within the fraction (Wentworth 1922). Additionally, sediment color (Munsell, 1923) was also determined to further explore the potential compatibility of nourishing existing beaches with sediment dredged from offshore deposits. Although sand was more abundant closer to shore, 16 out of the 28 samples collected in federal waters contained >50% sand (mean sand composition of all samples = 46.3% ± 22. 4%).
Habitat Characterization and Benthic Species Research
Thomas J. Trott, Ph.D., Benthic Ecologist, Maine Coastal Program
Technical Report
December 2020
Summary: In partnership with the Maine Department of Environmental Protection (DEP), MCMI conducted benthic species surveys in Casco Bay, Maine during August 2020, as part of the DEP project, Ambient Water Quality Monitoring and Eelgrass Monitoring and Mapping. Analysis of the benthic species found that annelids, molluscs and arthropods were dominant taxa among all stations, however differences among the assemblages were associated with sediment type.
Technical Report
Claire Enterline, Research Coordinator, Maine Coastal Program
Thomas J. Trott, Benthic Ecologist, Contractor to the Maine Coastal Program
Benjamin Kraun, Project Hydrographer, Contractor to the Maine Coastal Program
December 2020
Summary: Recent efforts in Maine have identified that understanding sediment transport and the management of beach sediment and nourishment materials is vital to creating better municipal and regional beach management plans, as well as informing dredging and sand disposal. We determined differences among biological communities among nearshore sand enhancement sites, determined sediment grain size based on surface grab samples and backscatter assessment, and assessed differences in grain size and biological community composition at one dredge disposal site pre- and post-disposal and compare these characteristics to a proposed new disposal site. We found that benthic species assemblages were representative of sandy bottom benthos, although there were some differences following sand disposal. We also found that among the beaches sampled, Wells Beach was distinct based on its species assemblage and the presence of a rare species that is sensitive to disturbance. This additional benthic habitat data provides coastal managers a more comprehensive understanding about how nearshore sand placement impacts these areas.
Publication: Aquatic Invasions 15(2): 282–296, https://doi.org/10.3391/ai.2020.15.2.05
Thomas J. Trott, Benthic Ecologist, Contractor to the Maine Coastal Program
Eric A. Lazo-Wasem, Peabody Museum of Natural History, Yale University
Claire Enterline, Research Coordinator, Maine Coastal Program
January 2020
Summary: The aorid amphipod Grandidierella japonica, originally described from northern Japan, is reported for the first time from the Gulf of Maine and Long Island Sound in the Northwest Atlantic Ocean. It was discovered among grab samples of eelgrass (Zostera marina) beds taken in Casco Bay, Maine in summer 2018 and has been found intertidally in Long Island Sound since 2013 along Connecticut shores. It occurs in habitats like its native range but also in rocky areas and tidepools in bedrock. The presence of adults of both sexes, ovigerous females, and immature stages in all collections indicates the species is established. Among males, some morphological characteristics of gnathopod 1 vary with increasing total body length: the number of accessory carpal teeth increases, the carpus shape (length/width ratio) changes, and numbers of stridulating ridges increase. Maine and Connecticut specimens are distinguished from each other by the shape of male gnathopod 1 basis. Morphological variation, temporal differences in discovery, and separation by the biogeographic barrier Cape Cod suggests Maine and Connecticut populations originate from separate introductions.
Publication: BioInvasions Records 8(3):598–607, https://doi.org/10.3391/bir.2019.8.3.16
Thomas J. Trott, Benthic Ecologist, Contractor to the Maine Coastal Program
Claire Enterline, Research Coordinator, Maine Coastal Program
August 2019
Summary: The cribrimorph bryozoan Cribrilina (Juxtacribrilina) mutabilis, originally described from Hokkaido, Japan, is reported for the first time in the Gulf of Maine and the whole of the Northwest Atlantic coast. In September 2018, numerous colonies of C. mutabilis were collected from eelgrass (Zostera marina) beds near Clapboard and Mackworth Islands, and Hog Island Ledge, all located within inner Casco Bay, Maine. Bryozoan colonies encrusted eelgrass, rockweed (Ascophyllum nodosum), and laminarian drift algae. Situated near the discovery location, the city of Portland (Maine, USA) is an active seaport, suggesting introduction through shipping as a likely introduction mechanism. The North Sea is hypothesized to be the most probable area for the source population. Since C. mutabilis appears to have high potential for introduction, it likely occurs on other parts of the Northwest Atlantic coast where it has yet to be identified and recorded.
Technical Report
Ivy Ozmon, Benthic Ecologist, Maine Coastal Program
May 2018
Summary: From 2015 to 2017 multibeam sonar surveys were completed for a 257 mi2 area in Midcoast Maine to create high resolution bathymetric maps and to collect backscatter intensity data for the region. Benthic sampling was conducted to ground truth surficial sediment
classifications made from interpretations of the bathymetric and backscatter maps, and these data were used in combination with the hydrographic data to inform benthic habitat classification. One hundred and ninety-four sites were sampled in the surveyed area to classify benthic habitat per the Coastal and Marine Ecological Classification Standard (CMECS). CMECS aquatic setting and geoformation designations were determined using analyses of hydrographic data, water column characterizations were made from analyses of vertical profiles of temperature and salinity, and seafloor substrate and benthic community classifications were generated from analyses of grab samples and seafloor imagery. Relationships between benthic community types and environmental variables were explored using multivariate statistical analysis methods. Predicted distributions of benthic communities were mapped for the surveyed area based on biotic-abiotic associations defined a posteriori, and using an abiotic surrogate, defined by a priori combined substrate-depth classification.
Assessing Various Methods to Map the Health and Extent of Eelgrass Beds, pdf, 1.87 MB
Grant Report to the Maine Outdoor Heritage Fund
January 2020
Summary: During July to September 2018, the Maine Coastal Program, Maine Department of Environmental Protection, independent consultant Seth Barker, Nearview LLC, Southern Maine Community College, Maine Geological Survey, and the Casco Bay Estuary Partnership performed a method comparison for mapping and delineating eelgrass beds at representative sites in Casco Bay, Maine. This project enhanced the state’s ability to map and assess eelgrass beds by comparing past used methods side-by-side with new technologies. Traditionally, eelgrass beds in Maine have been mapped by taking aerial images, hand digitizing eelgrass bed extent, and ground-truthing a portion of the mapped beds and percent cover using underwater video. In this project, we evaluated data collected by side-scan sonar, multibeam echosounder, Unmanned Aerial System imaging, and single-beam echosounder alongside the traditional aerial image-based method. We compared the data products, data collection feasibility, equipment and operational costs, and time required for each method at a representative sample of eelgrass beds in Casco Bay.
Invasive Species in Casco Bay: discovery, distribution and biological assessment, pdf, 1.48 MB
Grant Report to the Maine Outdoor Heritage Fund
December 2020
Summary: During July to November 2019, the Maine Coastal Program, Maine Department of Environmental Protection, Wells National Estuarine Research Reserve, and the Casco Bay Estuary Partnership performed invasive species sampling using different methods at representative sites in Casco Bay, Maine to document the spread of two newly discovered invasive species and to understand how different sampling methods may effect invasive species detection. Sampling subtidal areas of the Bay is as important to understanding the number and
extent of marine invasive species. Through this project, we 1) determined how wide-spread two non-native species discovered in 2018 were in Casco Bay and the habitat which they colonize, 2) gathered information about marine habitat and species communities throughout the Bay to understand how communities differ based on location, depth, substrate, and other factors, and 3) compared existing invasive species monitoring at docks and piers (constructed habitat) to natural habitat close to these structures to understand the impact of documented invasive species on nearby natural communities.
Multibeam Descriptive Reports
2019-2023 Combined Descriptive Report of Seafloor Mapping: Casco Bay, Maine, pdf, 25.2 MB
Peyton Benson, Maine Coastal Program
June 2023
Summary: Across multiple survey seasons, from July 2019 to April 2023, the Maine Coastal Mapping Initiative (MCMI) conducted hydrographic surveys using a multibeam echosounder (MBES) in state marine waters of Casco Bay, Maine. The surveying efforts were conducted to support endeavors to enhance coastal resiliency through identification and characterization of seafloor habitat to provide information necessary to managing the marine environment and economy. This report serves as a comprehensive summary of multiple combined survey efforts conducted by MCMI in Casco Bay, Maine. The combined efforts of these surveys collected approximately 35.15 mi2 (91 km2) of high-resolution multibeam data in the surveyed area and conducted sediment sampling at 71 sites to aid in seafloor characterization. The results were compared to existing nautical charts and changes in depth and wreck locations were noted for review by NOAA. MCMI also collected water column data and video at all sample locations, which will contribute to improved classification of substrate and modeling of benthic communities.
2022 Descriptive Report of Seafloor Mapping: Vicinity of Monhegan Island, pdf, 13 MB
Peyton Benson, Maine Coastal Program
June 2023
Summary: From June 2022 to April 2023, the Maine Coastal Mapping Initiative (MCMI) conducted hydrographic surveys using a multibeam echosounder (MBES) in federal marine waters off mid-coast Maine, southwest of Monhegan Island. The surveying efforts were conducted to support endeavors to enhance coastal resiliency through identification and characterization of seafloor habitat to provide information necessary to managing the marine environment and economy. In total, this survey effort collected approximately 76.18 mi2 (197.31 km2) of high-resolution multibeam data in the target area and conducted sediment sampling at 60 sites to aid in seafloor characterization. Throughout the survey period, MCMI also collected water column data and video at all sample locations which will contribute to improved classification of substrate and modeling of benthic communities.
2021 Descriptive Report of Seafloor Mapping: Vicinity of Casco Bay, pdf, 7.88 MB
Peyton Benson, Maine Coastal Program
September 2021
Summary: During May-August 2021, the Maine Coastal Mapping Initiative (MCMI) conducted hydrographic surveying using a multibeam echosounder (MBES) in marine waters in the vicinity of Casco Bay, off Halfway Rock and Long Island, Maine, respectively. The surveying efforts were conducted to support efforts to enhance coastal resiliency through identification and characterization of seafloor habitat to provide information necessary to managing the marine environment and economy. From April to August 2021, 39.7 mi2 (102.8 km2) of high-resolution multibeam data were collected in the vicinity of Casco Bay off Halfway Rock and within the inshore region off Long Island.
Benjamin Kraun, Maine Coastal Program
May 2021
Summary: During the survey season (April - November) of 2020 the Maine Coastal Mapping Initiative (MCMI) conducted hydrographic surveying using a multibeam echosounder (MBES) in the waters off Casco Bay, mid-coast Maine, and Penobscot Bay, Maine. The surveying was conducted in part to support the Maine Department of Marine Resources' (DMR) efforts to enhance coastal resiliency through identification, characterization, and protection of fisheries critical to the state's marine environment and economy. The surveys also coincide with state and federal efforts to update coastal data sets and increase high resolution bathymetric coverage for Maine's coastal waters. A total of approximately 45 mi2 (117 km2) of high-resolution multibeam data were collected. During the 2020 survey season the MCMI also collected sediment samples, water column data, and video in areas summarized in this report.
Benjamin Kraun, Maine Coastal Program
March 2020
Summary: During the 2018 survey season (July - November) and part of the 2019 field season (April - August), the Maine Coastal Mapping Initiative (MCMI) conducted hydrographic surveying using a multibeam echosounder (MBES) in the waters off southern and mid-coast Maine. The surveying was conducted in part to support the Federal Bureau of Ocean and Energy Management’s (BOEM) efforts to enhance coastal resiliency through identification and characterization of potential sand and gravel resources on the outer continental shelf that may be used for beach nourishment. The surveys also coincide with state efforts to update coastal data sets and increase high resolution bathymetric coverage for Maine’s coastal waters. A total of approximately 71 mi2 (184 km2) of high-resolution multibeam data were collected in the surveyed areas. An additional 6.5 mi2 were collected in nearshore waters for the purposes of assessing nearshore and riverine sand movement as well as mapping eelgrass beds.
Kerby Dobbs, Maine Coastal Program
October 2017
Summary: During May of 2017 the Maine Coastal Mapping Initiative (MCMI) conducted hydrographic surveying using a multibeam echosounder (MBES) in the estuarine portion of the lower Kennebec River from Bath to Fort Popham in midcoast Maine. Follow-up surveys were conducted on June 2, 2017 in three select areas because they represent zones where sediment is highly mobile and the comparison between surveys on two separate occasions is a valuable tool for estimating sediment transport dynamics in the Kennebec River estuary; especially where the deposition of sediment may impede safe navigation. The surveying was conducted at the request of the Maine Submerged Lands Program to help accomplish a variety of objectives, including but not limited to: identification and delineation of submerged cables in charted cable areas, locate and delineate submerged debris, evaluate sediment transport and potential sand and gravel resources for beach nourishment, provide up to date navigational data for NOAA’s Office of the Coast Survey, establish baseline habitat coverage, and to possibly open previously restricted areas to commercial fishing, aquaculture, and overnight recreational boating.
Kerby Dobbs, Maine Coastal Program
October 2017
Summary: During the survey season (April-September) of 2017 the Maine Coastal Mapping Initiative (MCMI) conducted hydrographic surveying using a multibeam echosounder (MBES) in the waters off of mid-coast Maine. The surveying was conducted in part to support the Federal Bureau of Ocean and Energy Management’s (BOEM) efforts to enhance coastal resiliency through identification and characterization of potential sand and gravel resources on the outer continental shelf that may be used for beach nourishment. The surveys also coincide with state efforts to update coastal data sets and increase high resolution bathymetric coverage for Maine’s coastal waters. A total of approximately 125 mi2 (325 km2) of high-resolution multibeam data were collected in the surveyed area. During the 2017 survey season the MCMI also collected sediment samples, water column data, and video in 69 locations.
Kerby Dobbs, Maine Coastal Program
February 2017
Summary: In May of 2016 the Maine Coastal Mapping Initiative (MCMI) conducted hydrographic surveying within the navigable waters of the Saco River between Camp Ellis and the Biddeford/Saco area located approximately 8 km (5 mi) upstream. Bathymetric (e.g. depth) and backscatter (e.g. seafloor substrate) data were collected using a multibeam echosounder (MBES). Preliminary analyses of these data provided the basis for a more specific investigation using underwater video recordings to help characterize the distribution and nature of submerged debris in the vicinity of a proposed dredging of the federal channel in the Biddeford/Saco portion of the Saco River. The results of the submerged debris investigation may facilitate further assessment of potential hazards posed by submerged debris and/or shallow portions of navigable waters within this portion of Saco River. This project also coincides with state efforts to update coastal data sets and increase high resolution bathymetric coverage for Maine’s navigable waters and provides new data in the areas covered by National Oceanic and Atmospheric Administration (NOAA) nautical charts (e.g. coastal and harbor) 13286 and 13287 in southern Maine.
2016 Descriptive Report of Seafloor Mapping: Mid-coast Maine, pdf, 17.7 MB
Kerby Dobbs, Maine Coastal Program
January 2017
Summary: During the survey season (April-October) of 2016 the Maine Coastal Mapping Initiative (MCMI) conducted hydrographic surveying using a multibeam echosounder (MBES) in the waters off of mid-coast Maine. The surveying was conducted in part to support the Federal Bureau of Ocean and Energy Management’s (BOEM) efforts to enhance coastal resiliency through identification and characterization of potential sand and gravel resources on the outer continental shelf that may be used for beach nourishment. The surveys also coincide with state efforts to update coastal data sets and increase high resolution bathymetric coverage for Maine’s coastal waters. A total of approximately 62 mi2 (161 km2) of high-resolution multibeam data were collected, 57 mi2 (148 km2) in the “mainscheme” area of federal (19 mi2) and state (38 mi2) coastal marine waters, and 5 mi2 (13 km2) in nearshore embayments and estuaries. During the 2016 survey season the MCMI also collected sediment samples, water column data, and video in 54 locations, 43 in state water and 11 in federal waters, all within the mainscheme survey area.
2015 Descriptive Report of Seafloor Mapping - Midcoast Maine, pdf, 2.31 MB
Kerby Dobbs, Maine Coastal Program
January 2016
Summary: During the survey season (May-November) of 2015 the Maine Coastal Mapping Initiative (MCMI) conducted hydrographic surveying using a multibeam echosounder (MBES) in the waters off of mid-coast Maine. The survey was conducted in part to support the federal Bureau of Ocean and Energy Management’s (BOEM) efforts to enhance coastal resiliency through identification and characterization of potential sand and gravel resources on the outer continental shelf that may be used for beach renourishment and for state efforts to update coastal data sets and increase high resolution bathymetric coverage for Maine waters. A total of approximately 82.5 mi2 (213.5 km2), 80 mi2 (207 km2) mainscheme and 2.5 mi2 (6.5 km2) inshore, of high-resolution multibeam data were collected by MCMI between May and November 2015. During the 2015 survey season the MCMI also collected sediment samples in 61 locations, 43 in state water and 18 in federal waters, in the approximately 80mi2 (207 km2) mainscheme survey area.
Descriptive Report for seafloor mapping of areas off southern Maine, pdf, 1.51 MB
David Armstrong, Maine Coastal Program
March 2015
Summary: The Maine Coastal Mapping Initiative conducted a multibeam survey using a Kongsberg EM 2040C multibeam in the waters off the coast of southern Maine. Data was acquired from June to October 2014. The survey was conducted as part of a grant from Bureau of Ocean and Energy Management (BOEM), for beach restoration and reconciliation. The bathymetry and backscatter will primarily be used to determine the potential for sandy deposits. The project also coincides with state efforts to update coastal data sets and bring high resolution bathymetric maps into Maine waters. This grant allowed for the purchase of new multibeam sonar, positioning equipment, and other equipment needed for bathymetric mapping and bottom sampling. In addition to multibeam work the survey also conducted drop camera and bottom sampling to ground truth the data. The project provides new data in the areas covered by NOAA nautical charts 13286 in southern Maine, and 13296 and, 13288 in the Boothbay Harbor/ Linekin Bay region of Maine.
Special Projects
Benjamin Kraun, Hydrographer, Contractor to the Maine Coastal Program
December 2018
Summary: MCMI worked with the Maine Bureau of Parks and Lands to explore Pemaquid Harbor for remains of the Angel Gabriel, a vessel lost in 1635 shortly after her arrival from Bristol, England. This project collected multibeam echosounder data together with underwater video to document and catalogue any anomalies from the seabed that may warrant further investigation.
Memo Report: Submerged Glacial Features Offshore Kennebunkport, Southern Maine, pdf, 2.02 MB
Kerby Dobbs, Hydrographer, Contractor to the Maine Coastal Program
March 2017
Summary: In 2014, MCMI conducted hydrographic surveys offshore of Cape Porpoise in Southern Maine. The main purpose of these surveys was to identify potential sources of sand and gravel for beach nourishment, and to update coastal data sets and increase high resolution bathymetric coverage for Maine’s coastal waters. Visualization and interpretation of the seabed features from these data and their derivatives also provide additional geomorphological information for the region. This report describes the glacial history of the area and the glacial landforms in the hydrographic survey data. The high-resolution MBES data collected by MCMI makes it possible to describe small-scale underwater sediment patterns that would not otherwise be described.
Preliminary Report of Saco River Submerged Debris Investigation, pdf, 2.77 MB
Kerby Dobbs, Hydrographer, Contractor to the Maine Coastal Program
June 2016
Summary: MCMI partnered with the Maine Submerged Lands Program and the towns of Biddeford and Saco for this investigation to help locate submerged debris as well as provide up-to-date, high-resolution bathymetry data in the vicinity of a proposed dredging area in the Biddeford/Saco portion of the Saco River. Bathymetric (e.g. depth) and backscatter (e.g. seafloor substrate) data were collected using a multibeam echosounder (MBES). Preliminary analyses of these data provided the basis for a more specific investigation using underwater video recordings to help characterize the distribution and nature of submerged debris in the vicinity of a proposed dredging of the federal channel in the Biddeford/Saco portion of the Saco River. This project also coincides with state efforts to update coastal data sets and increase high resolution bathymetric coverage for Maine’s navigable waters and provides new data in the areas covered by National Oceanic and Atmospheric Administration (NOAA) nautical charts (e.g. coastal and harbor) 13286 and 13287 in southern Maine.