Historical Wetlands of the Southern California Coast

Under the direction of some of the leading American scientists of the 19th century, the United States Coast Survey (USCS) created exceptionally accurate and detailed maps of the country's coastline. These surveys (commonly referred to as "T-sheets") are the single most important data source for understanding the physical and ecological characteristics of the US shoreline prior to substantial Euro-American modification. Their depictions of coastal wetlands and estuaries prior to major development are valuable tools for coastal zone planning and estuary management and form an important foundation for more detailed investigations of historical extent and condition of coastal wetlands.Please visit http://www.caltsheets.org for more information, including links to the associated reports: Wetlands of the Southern California Coast: Historical Extent and Change over Time (Stein et al. 2014), and Historical Wetlands of the Southern California Coast: An Atlas of U.S. Coast Survey T-Sheets, 1851-1889 (T-Sheet Atlas) (Grossinger et al. 2011).This dataset was created based on expert interpretation of georeferenced T-sheets spanning the entire coastline of Southern California. Mapping methodology is described in detail in Stein et al. 2014. This dataset (phase 2) updates and replaces earlier GIS datasets created for, and distributed concurrently with the 2011 T-sheet Atlas (phase 1).---Attribute table fields:Primary_1: Level 1 feature classification, generally based on T-sheet symbology.Primary_2: Level 2 feature classification, generally based on landscape position of the feature. Subclassification: Level 3 features classification, generally based on interpreted hydrology and/or mouth closure as depicted on the T-Sheet. Simp_Class: Simplified classification, used for summarizing historical habitat areasWeb_Class: Simplified classification, used for symbology in web and paper cartographyTsheet_Num: the register number of the original T-sheet from which the feature was digitizedYear_: the publication year of the original T-sheet from which the feature was digitizedSurveyor: the surveyor(s) of the original T-sheet from which the feature was digitizedComb_Tsheet_Num: if completed, denotes the register number of additional (overlapping) T-sheets from which the feature was digitizedComb_Years: if completed, denotes the publication year of additional (overlapping) T-sheets from which the feature was digitizedComb_Surveyors: if completed, denotes the surveyor(s)of additional (overlapping) T-sheets from which the feature was digitizedSystem_Num: an ID number applied to each feature (line or polygon) that is part of the same coastal system. The numbering begins at Pt. Conception. For the definition of coastal system, refer to Stein et al. 2014. NULL values indicate that the feature did not meet the criteria for a coastal system as defined for this study.System_TermType: A description of where a coastal system terminates (e.g. into an ocean, lagoon, or beach)System_Size: Size classification of the system the feature belongs to.Marsh_Complex: Name of the marsh complex a feature is part of, used in some analyses in the T-Sheet Atlas (Grossinger et al. 2011). Square brackets [ ] denote features that were not included in Phase 1 analysesArchetype: A descriptor of the type of coastal system the feature belongs to. Revision to Grossinger et al. 2011 p42In_Analysis: (Polygons only)1: Feature is included in historical area analysis. 0: Not included In_PastPresent_Analysis: (Polygons only) 1: Feature is included in past/present area comparisons. 0: Not included Cowardin_Crosswalk: (Polygons only)Wetland classification used for comparison of past and present wetland extentsMapping_Phase: 1: Mapped during Phase 1 (2011). 2: Mapped during Phase 2: (2014). 12: Mapped off of a "Phase 1" T-sheet, but added or corrected based on Phase 2 refined methods. Terminus_Type: Description of where a channel or open water feature terminated near the coast (not used in analysis). Used to develop System_TermType attributeTerminus_Dist: Distance between the terminus of a feature and the shoreline (nonzero values). Marked as 0 if a channel terminates into a lagoon. The associated lagoon then receives a non-zero value based on its distance from the shoreline (not used in analysis).Comments: Mapper comments on specific features. Text transcribed directly from the T-sheets is marked in quotes.