ISMSE Long Term Shoreline Change Rates

The information associated with this data layer describes long-term (approximately 150 years) shoreline change rates across the 3-town shoreline of the Intermunicipal Shoreline Management project. USGS data from the Massachusetts Shoreline Change Project (2021 update) was used to create this data layer. Transect locations and attributes were extracted from the long-term rates dataset. Rate calculations were computed by the USGS using the Digital Shoreline Analysis System (DSAS) version 5.1. For this layer, the absolute value of the linear regression rate of change was used to rank rates in ascending order to create a visual representation of the relative magnitude of change along the entire 3-town shoreline of Brewster, Dennis and Orleans. The length of each transect is a relative measure of change. A longer polyline indicates a greater rate of change when compared to all other transects within the project extent. Negative values indicate erosion and positive values indicate accretion. For more information regarding the original dataset used to create this visual representation layer please see Bartlett, M.K., Henderson, R. E., Farris, A.S., and Himmelstoss, E.A., 2021, Massachusetts shoreline change project, 2021 update–A GIS compilation of shoreline change rates calculated using Digital Shoreline Analysis System version 5.1, with supplementary intersects and baselines for Massachusetts: U.S. Geological Survey data release. https://doi.org/10.5066/P9YGIYFX The characteristics that make shorelines resilient and their ability to respond to natural hazards operate independently of municipal boundaries. To facilitate and promote consistent and synergistic management techniques shoreline characteristics of three adjacent communities were examined in the absence of municipal boundaries in order to develop a comprehensive shoreline management framework. The three adjacent communities, Brewster, Dennis and Orleans, partnered to develop a framework for an intermunicipal approach to shoreline management to promote short- and long-term science-based decisions that will maximize the effectiveness and efficiency of community responses to the increased threat of coastal hazards. GIS-based datasets comprising the Intermunicipal Shoreline Management Database were compiled from existing sources and supplemented by additional data where appropriate. Contemporary shoreline resilience conditions have been characterized throughout the study area to identify issues and challenges currently confronting each town’s management efforts. This assessment is based on existing data (available through CZM’s Shoreline Change database, MORIS and MassGIS), information from multiple MCZM Coastal Resiliency projects (Borrelli et al., 2016; Borrelli et al., 2017; Giese et al., 2013, Giese et al., 2018) and other resources including the U.S. Army Corps of Engineers, the U.S. Geological Survey, NOAA, the Barnstable County Dredge Program, and records from the individual towns.本数据图层所关联的信息，描述了跨市镇海岸线管理项目（Intermunicipal Shoreline Management project）所辖三镇岸线的长期（约150年）海岸线变化速率。 本数据图层基于美国地质调查局（USGS）发布的马萨诸塞州海岸线变化项目（Massachusetts Shoreline Change Project，2021年更新版）数据制作。样带（Transect）的位置与属性信息均从长期变化速率数据集提取，速率计算由USGS借助海岸线分析系统（Digital Shoreline Analysis System，DSAS）5.1版本完成。 本图层采用线性回归变化速率的绝对值，按升序对速率进行排序，以此可视化呈现布鲁斯特（Brewster）、丹尼斯（Dennis）与奥尔良（Orleans）三镇全域岸线变化的相对幅度。 每条样带的长度为变化量的相对度量指标：在项目研究范围内，多段线越长，代表其变化速率越高。负值代表海岸侵蚀，正值代表海岸淤积。 如需了解本可视化图层所基于的原始数据集的更多信息，请参阅：Bartlett, M.K.、Henderson, R.E.、Farris, A.S.及Himmelstoss, E.A.于2021年发布的《马萨诸塞州海岸线变化项目2021年更新版——基于DSAS 5.1版本计算海岸线变化速率的GIS汇编数据集，含马萨诸塞州补充交汇点与基线》（美国地质调查局数据发布），链接：https://doi.org/10.5066/P9YGIYFX 决定海岸线韧性的特征及其应对自然灾害的能力，不受市镇行政边界的限制。为推动形成统一协同的岸线管理技术方案，本次研究打破行政边界限制，对三个相邻社区的岸线特征展开分析，以构建综合性岸线管理框架。 布鲁斯特、丹尼斯与奥尔良三镇携手合作，共同制定跨市镇岸线管理框架，旨在推动基于科学的短期与长期决策，最大限度提升社区应对日益严峻的海岸灾害威胁的响应效率与效果。 构成跨市镇海岸线管理数据库的地理信息系统（GIS）数据集，均从现有数据源整合而来，并在适宜情况下补充了额外数据。 本次研究对整个研究区域的当前岸线韧性状况进行了特征刻画，以识别当前各城镇岸线管理工作面临的问题与挑战。 本次评估所用数据来源包括：现有公开数据（可通过马萨诸塞州海岸带管理局（CZM）岸线变化数据库、MORIS及马萨诸塞州地理信息系统（MassGIS）获取）、多项马萨诸塞州海岸韧性项目（MCZM）的相关资料（Borrelli等，2016；Borrelli等，2017；Giese等，2013；Giese等，2018），以及其他多类资源，如美国陆军工程兵团、美国地质调查局、美国国家海洋和大气管理局（NOAA）、巴恩斯特布尔县疏浚项目，以及各城镇的存档记录。