Historical Bathymetric Data for the Lower Passaic River

Transcription

1 Historical Bathymetric Data for the Lower Passaic River 4th Passaic River Symposium June 22nd, 2010 Dr. William Hansen Jeffrey Cranson Worcester State College Project Supported by The Hudson River Foundation for Science and Environmental Research

2 Outline of Presentation Lower Passaic River Study Area. Historical Hydrographic Data. Processing and Rectifying data Interpolation Procedure Bathymetric Surfaces and Differences Conclusion

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4 Dredging History Arlington Reach 200 feet wide channel 16 feet authorized depth. Last Dredged in 1930 (Iannuzzi, et al. 2002) Newark and Kearney Reaches 300 feet wide channel. 20 feet authorized depth, historically maintained at 16 feet. Last Dredged in 1950 (Iannuzzi, et al. 2002) Harrison Reach 300 feet channel, 20 feet authorized depth, maintained at 16 feet. Last dredged Point No Point Reach 300 feet channel,30 feet authorized, 30 maintained depth. Dredged 1946, 1951, 1957, 1962, 1965, 1971, 1972, 1977, (Iannuzzi, et al. 2002)

5 Historical Bathymetry Data Current hydrographic surveys are done digitally. Started in 1999 for Passaic River Historical Bathymetry on microfiche in District Office. Time periods available were: 1949, 1952, 1966, 1973 and None of the surveys had complete coverage of the study area.

6 Historical Bathymetry Data Scanned jpeg files of US Army Corps of Engineers Hydrographic Survey sheets on Microfiche were obtained from NY District through a FOIA request.

7 Base map Data 2007 Digital Bathymetry data was provided by the Army Corps in CAD format. Channels were extracted and used in rectification procedure. Digital OrthoPhotos downloaded from State of New Jersey

8 Historical Bathymetry Data Scanned Surveys were rectified to NJDEP high resolution Digital Ortho photos and Digital Channel data.

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10 Digitizing Procedure Hydrographic Survey point locations and depth values were digitized into GIS point shapefiles using ArcGIS 9.3. New Jersey State Plane coordinates Fields - Depth and Depth with tidal datum change Check plots were created, values displayed by graduated color and labeled. Survey depths were adjusted for tidal datum change since 1900.

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12 Tidal Datum Change Based on NOAA Tidal Station The Battery, NY Baseline 1900 Mean Sea Level 1.54 Feet April 19-22, 1949 Mean Sea Level (MSL) 2.13 feet Difference ft. April 21 26, 1966 MSL 2.29 ft. Difference 0.75 ft. April 18-24, 1976 MSL 2.25 ft. Difference 0.71 ft. Nov-Dec ft. Difference 0.89 ft.

13 Interpolation Process of taking random sample point locations and values and mathematically calculating values at regular grid cells. Spline interpolator fits a minimum-curvature surface through the points. Best for gently varying surfaces such as elevation, water table heights, or pollution concentrations. Inverse Distance Weighting uses n number of neighboring points and weights the value of each point by its distance to the cell being analyzed and averages the values. Kriging uses a Semivariograms (measure the strength of statistical correlation as a function of distance.) to associate some probability with each prediction. Interpolation methods, including kriging, for this highly anisotropic dataset yielded poor results.

14 Data Transformation Spatial Locations were transformed to along channel distances (Y) and cross channel distances (X), therefore straightening the river.

15 Transformation

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25 Depth in Feet Upstream New Jersey Turnpike South Bank Cross Channel Distance in Feet North Bank

26 Diamond Alkali Site Cross Sections Depth in Feet South Bank Cross Channel Distance in Feet North Bank

27 River Bank Park Depth in Feet South Bank Cross Channel Distance in Feet North Bank

28 Downtown Newark Depth in Feet South Bank Cross Channel Distance in Feet North Bank

29 Conclusion Significant deposition has occurred in channel in the Lower Passaic. Major deposition between 1949 and Highest sedimentation rates along inner bend of navigation channel. Up to 9 feet in Harrison Reach. Timeframe of largely unregulated discharge Significant deposition and reworking of the thalweg between 1966 and Deposition highest at lower end of Harrison Reach. Erosion and deposition between 1976 and 1986 In channel deposition Significant areas of off-channel erosion