Description: Aggregation and scoring of marsh benefits throughout the Chesapeake Bay and Coastal Bays can help managers and practitioners to prioritize areas for protection and restoration. This dataset is the overall Marsh Protection Index score. The dataset uses USGS’ Conceptual Marsh Units (CMUs) to aggregate marshes into mini-watersheds and then scores each CMU for four categories: 1. Marsh health (out of 15 points), 2. Marsh proximity to people (out of 15 points), 3. Marsh proximity to other habitats (out of 20 points but no units score higher than 15) and 4. Marsh wave attenuation (out of 15 points). The maximum score for each of these categories is 15, giving a maximum of 60 for the most protective marshes. The scoring description for each category is detailed within the sub-layers related to those scores within the MPI and Marsh Resilience Portfolio. Last updated: 03/30/2026
Description: Marsh health sub-layer within the Marsh Resilience Portfolio, maximum 15 points. USGS’ Marsh Lifespan Dataset was first used to determine a ‘marsh management suggestion’ for a marsh unit. This dataset combines vegetated elevation with the Unvegetated to Vegetated Ratio (UVVR) to classify marshes as restore, protect, monitor and evaluate. For each CMU, an ELEVATION_UVVR field was calculated according to the thresholds on the chart below (elevation high >0.4m, elevation low <= 0.4m, UVVR low <= 0.15, UVVR High > 0.15). Each CMU was then scored according to its management suggestion as follows: Protect (high_low) = 15 points, monitor (low_high) = 10 points, restore (high_high) = 5 points, evaluate (low_high) = 0 points. This scoring field is labeled health_score in the MPI attribute table. You can also view the restoration suggestion of each CMU by viewing the management_strategy field within the MPI attribute table.Last updated: 03/30/2026
Description: Maximum 15 points. A wave attenuation index was created for use in the MPI project, using a dataset of modeled wave height provided by George Mason University (GMU) that was used as a proxy for exposure. Higher wave heights for marshes indicated a higher amount of exposure during storms, giving them a higher score for attenuation benefits. Although the data is only available upon request, users can read more about the work GMU did to produce the wave height modeling in the following papers: 1, 2, 3, 4. The wave height data was combined with marsh size (larger marshes scoring higher points) to create the wave attenuation index, and the data was scored from 0-10. For each CMU, the attenuation score was summarized within to get the average wave attenuation score for that marsh unit. This data was binned and translated to a 0-15 scale accordingly: between 0 and < 2.5 received 0 for MPI, >= 2.5 and < 3.5 received 5 for MPI, >=3.5 and <=5 received a 10 for MPI, >5 received a 15 for MPI. This scoring is labeled wa_at_score_mean in the MPI attribute table.Last updated: 03/30/2026
Description: Proximity to habitats sub-layer within the Marsh Resilience Portfolio, maximum 15 points. Conceptual marsh units scored additional points when within 250 meters of other important habitats. This is the same distance used to determine this score in the Coastal Resiliency Assessment. VIMS Submerged Aquatic Vegetation (SAV) presence was combined for the years 2020-2023 and this was buffered by 250 meters. Any CMU within this buffer received 5 additional points for sav_score. Maryland Forest Presence, derived from Chesapeake Conservancy’s Land Use Land Cover (LULC) dataset, was buffered by 250 meters and any CMU within this buffer received 5 additional points for for_score. Maryland dune presence was determined using an NPS Assateague Island Dune dataset provided by The Nature Conservancy. Finally, oyster presence from DNR’s Benthic Habitat layer was buffered by 250 meters, and marsh units scored an additional 5 points for oys_score. The four proximity to habitat scores (SAV, oysters, forests, and dunes) were combined (summed) in a new field habitat_score that can be viewed in the MPI dataset attribute table. The types of habitats that received points for each marsh unit are also available under the field Nearby_Habitats.Last updated: 03/30/2026
Description: Proximity to people sub-layer within the Marsh Resilience Portfolio, maximum 15 points. Conceptual marsh units scored additional points if they were located within 500 meters of people. University of Maryland's Dasymetric Population modeling was used to determine the presence of people/homes. Dasymetric population data was analyzed by using the Euclidean distance tool, with a maximum distance of 500 meters of distance accumulation. A polygon of Maryland’s shoreline was used to restrict the distance accumulation so that marshes across a river from population data but within 500 meters did not receive points for proximity to people (as they are likely not protecting that population).The maximum distance was determined through discussions with George Mason University staff, creating the assumption that the 500 meters is the approximate maximum width of marshes required to attenuate waves during a storm in the Chesapeake Bay. If a marsh unit was within 500 meters of people, it received an additional 15 points and if it was not it received 0 additional points. This is scored as the field population_score in the MPI dataset attribute table. Last updated: 03/30/2026
Description: Marsh management suggestion sub-layer within the Marsh Resilience Portfolio, categorical data with outputs of protect, restore, monitor, evaluate, and insufficient data. USGS’ Marsh Lifespan Dataset was used to determine a ‘marsh management suggestion’ for a marsh unit. This dataset combines vegetated elevation with the Unvegetated to Vegetated Ratio (UVVR) to classify marsh management suggestions as restore, protect, monitor and evaluate. For each CMU, an ELEVATION_UVVR field was calculated according to the thresholds on the chart below (elevation high >0.4m, elevation low <= 0.4m, UVVR low <= 0.15, UVVR High > 0.15). This field is labeled management_strategy in the MPI attribute table.Last updated: 03/30/2026