Bear River Dike Removal GIS

Existing GIS spatial data lacks the resolution to use them at the scale required for the Bear River dike removal project.  These data sources supply a wealth of information by capturing past site conditions.  A knowledge of the many dynamic states from the sites past can be used to predict more accurately the outcome and effectiveness of future planning efforts.  We really want to know is the Bear River’s effectiveness at the site for potential channel migration patterns, overland flows, and vegetation changes, each has been effected or even subdued by the presence of a dike. 

Specific needs for mapping:

·        Original 1942 low elevation air photos of the Bear River Estuary.

·        Original 1996 low elevation air photos of the Bear River Estuary.

·        Low elevation fly-over in Brad’s airplane?

·        Large scale USACE mapping, often includes supplementary information, bathymetric data, location of historic pilings, dolphins that may not be visible but pose consideration in the design of a dike removal project.  USACE mapping interpretation can reveal historical trends in the local river system by identifying hydraulic and geomorphic features.

·        Large scale USCGS mapping enhances the understanding of the local hydraulic processes in operation around the project area.

·        Copy of digital Pacific County coverage of the Bear River estuary.  Additional sources of digital data would be helpful.

·        As many low elevation air-photos as are available

Creation of (large scale) spatial data sets based on surveyed data and modified county data layers.  These layers will serve to:

·        Collect large scale data about surficial physical features in the project area for planning purposes:

·        A brief surface vegetation survey.  Vegetation types are a collection of representatives groups of vegetation types on the surface of the study area. These groups may consist of trees, shrubs with the potential to be further sub-classified into various species.  Vegetation sampled before dike removal is important establish a basis to show trends in the data as the salt marsh returns to the surface of portions of the study area. 

·        Surveying the extent of surface water areas will provide useful decision making materials that in project planning indicate depressional areas within the project boundaries.

·        Surveying the dike area is important to estimating the volume of material it’s composed of and to approximate the area of immediate impact.  This is important to consider with topography when estimating when redistributing the dike on the surface of the project area.

·        Shoreline locations in proximity to the various project areas will provide a link to tidal cycles obtained from tidal software data.  This leads into being able to predict where the new shoreline and features will be located after the dike is removed.

·        Extent of road areas is important to compare to local hydrography to determine if the roads presence has interrupted surface water flow and the transportation of sediment. 

·        The extent of other compacted areas with a variety of permeability fluctuation due to compaction and other soil characteristics.  The response of the land surface (inc. fill) in relationship to the introduction of water should be understood at each step. 

·        public land survey and other grid type reference is critical for the development of a spatial reference coordinate system that can be used to store any surveyed features location in relationship to all other locations within the survey area.

·        property ownership valuable to determine those adjacent property owners who could be adversely effected by dike breaching.

·        adjacent features and themes provide the needed continuity of surface features within the study area to the outside. Surface water adjacent geomorphologic features and vegetation are the main components of this effort get the bigger picture.  The location of the adjacent dike across the site area could impact the site area by being a hydraulic barrier to half the Bear River’s local discharge.  Could this lead to cutting a new channel closer to the site, a push away from the southern dike? 

·        topography adds to project planning in by relationships between several aspects of this project.  Water constantly changes velocity, salinity and elevation with respect to the surface of the study area.  Local topographic relationships between water and land must be understood in order to provide information for project planning.  The site ideally will have a subtle slope towards the main channel to provide flow that carves channels and prevents pooling and hyper-saline lakes. 

Large scale data will be essential to this project for contributing to:

·        Partitioning the extent of study area into individual project areas.  To test the development of a variety of proto-channels.  Channel types in various stages of development ranging from a bank notch to a fully cut dendritic pattern.  The channels development  takes place after acquisition of a given channel eventually leading to channel alteration by the re-established hydraulic cycles placed on the surface.

·        Planning discreet projects within the study area. Wood placement to reinforce proto-channels and other places in a variety of sizes and functions.

·        Storing collected pre-project data, surface covering, locations, characteristics, etc..

·        Storing data collected during the various project sequences, channels, dike, and

·        Storing any monitoring data collected in a digital format.

·        Pre-and post project analysis of surveyed data to detect changes in the location of surface features in time.  Detailed maps can be produced to illustrate channel changes through the study period.  These kinds of dynamic changes to the surface of the site are not known until they are mapped. Planning stages of this project should rely heavily on the usage of interpreted and mapped information.