Progress Report

CICEET Progress Report for the period 10/4/04 Through 3/15/05

Project Title: Development of an integrated data acquisition and coastal marine GIS analysis system for habitat mapping and change detection in the Elkhorn Slough NERR
Principal Investigator(s): Rikk G. Kvitek

Figures
Figure 1

Figure 1
Figure 2

Figure 2
Figure 3

Figure 3
Figure 4

Figure 4

Tables
Table 1

Table 1
Project Summary
Habitat change and loss due to anthropogenic and natural factors is the major environmental problem facing many coastal and estuarine resource management agencies. Harbor creation adjacent to the Elkhorn Slough National Estuarine Research Reserve (ESNERR) has led to increased tidal scour that is rapidly eroding the banks, salt marsh and main channel of Elkhorn Slough, destroying freshwater wetlands, and inundating an active railroad line. There is also evidence that seismic activity may be contributing to the loss of salt marsh habitat and increased tidal scour. The purpose of this project is the development and implementation of an integrated system of RTK GPS telephony, acoustic remote sensing, and marine GIS tools for marine habitat mapping and change detection within the ESNERR. This collaborative work has been undertaken with 4 industry partners involved in the commercial development of new technologies in three main areas: 1) RTK GPS for hydrographic survey applications, 2) automated seafloor substrate classification and 3) tidally explicit marine GIS. Working with Trimble Navigation, are breaking new ground in RTK-based hydrographic surveying and on-the-fly tidal modeling. Working with Triton-Elics and Quester Tangent, we are developing automated habitat discrimination products for classifying subtidal estuarine habitats and plant communities using sidescan sonar data. We are also working closely with ESRI to provide the only estuarine data set to be used in the development of the ArcGIS Marine Data Model. The goal of this model is to create a Marine GIS capability for addressing the multiple dimensionality and dynamism of marine data, handling the temporal and dynamic properties of shoreline and coastal processes, dealing with the inherent fuzziness of ocean boundaries, and the need for spatial data structures that vary their relative positions and values over time.

These new technologies are being developed, integrated and applied to achieve the following research objectives at the ESNERR over the 2-year project period:

  • Classify and map the distribution of marine habitats within the ESNERR
  • Determine the spatial and temporal distribution of rates of sediment erosion, deposition and habitat change
  • Determine the elevations and rates of subsidence of the Southern Pacific Railway across the salt marsh
  • Test the hypothesis that subsidence during 1989 Loma Prieta earthquake has contributed to tidal flooding and marsh loss in the headword region of the Elkhorn Slough

The Seafloor Mapping Lab at CSUMB, making use of its existing RTK GPS, multibeam, sidescan and sub-bottom sonar survey systems, is responsible for all data collection.

Accomplishments
Progress On Tasks
Acoustic surveys (multibeam, sidescan sonar, sub-bottom profiling)
Sidescan sonar surveys
We have now completed the processing, mosaicing and evaluation of the sidescan sonar data for the slough. At this point, there does not appear to be enough variation in bottom type within the slough to support autoclassification of the imagery using the products from Triton-Elics or Quester Tangent as originally planned. The substrate types include fine sand, silts and clays, with some shell debris in the deep channel axis.

Bathymetric surveys
We have now used the comprehensive Elkhorn Slough DEM (merged results from our multibeam and singlebeam bathymetry surveys and the new LIDAR topographic data for the entire watershed from NOAA and described in previous progress report) (Figure 1) to calculate the MHHW to MLLW tidal prism for the Elkhorn Slough (Figure 2, Table 1).

We have also completed the first bathymetric changed detection analysis from the 2001 and 2003 serial multibeam bathymetry surveys (Figure 3 and Figure 4). These results reveal a striking pattern of tidal scour and sediment erosion deepening the main channel, but with deposition and shoaling occurring along the adjacent mud flats. This pattern of deepening and widening main channel flanked by shoaling mud flats extends from the slough mouth to Kirby Park (red arrow in Figure 1). North of Kirby Park no significant erosion was detected (Figure 4)

The Elkhorn Slough Tidal Wetlands Management Plan Team and researchers at MBARI, Moss Landing Marine Labs, and Stanford University are already applying the results from the bathymetry analyses (watershed DEM, tidal prism, spatial distribution of erosion and deposition) described above. In addition, the results from the sub-bottom profiling survey are being used the Elkhorn Slough Tidal Wetlands Management Plan Team and their contractors to assess erosion potential of the main channel. We are now in the planning stages for the final bathymetric survey for change detection in the ESNERR to be run in Summer 2005.

Terrestrial surveys
The scope of the railroad bed elevation survey may have to be reduced due to safety concerns. Unless we can be certain of detecting approaching trains, we shall not survey the elevation of the rails.

Difficulties Encountered
No difficulties have been encountered during this period, with the exception of being able to hear approaching trains.

Anticipated Success in Meeting Project Objectives
The project is on schedule, and all objectives should be achieved on time with the possible exception of the railway elevation survey.

Preliminary Data
The merged bathymetry and LIDAR topography data set is available and currently in use by a variety of regional researchers and resource managers.

Tasks and activities for next reporting period

Tasks for the next reporting period
Completion of final bathymetric survey.

Expenditures
Expenditures have been in the range anticipated for the work accomplished to date.