Washington Coastal Geodetic Control Network: Report and Station Index Developed in Support of the Southwest Washington Coastal Erosion Study October 1999 Department of Ecology Publication #99-103 Richard C. Daniels1, Peter Ruggiero1, and Leonard E. Weber, LS2 1Washington Department of Ecology Shorelands & Environmental Assistance Program Coastal Monitoring & Analysis Program Olympia, WA 98504-7600 (360) 407-6000 2Weber GPS 5509 44th Court SE Lacey, WA 98503 ii TABLE OF CONTENTS Page LIST OF FIGURES......................................................................................................................... v LIST OF TABLES ........................................................................................................................vii SECTION 1: THE WASHINGTON COASTAL GEODETIC CONTROL PROJECT................. 1 1. Background Information ................................................................................................. 1 2. Existing Vertical and Horizontal Control........................................................................ 3 3. Network Design and Implementation ............................................................................. 4 3.1 Site Reconnaissance.......................................................................................... 4 3.2 Preliminary Field Operations ............................................................................ 5 3.3 Survey Operations............................................................................................. 9 3.4 Adjustment of the Data ................................................................................... 11 3.5 Additional Stations.......................................................................................... 14 3.6 Project Summary............................................................................................. 15 4. Oregon Elevation Offset................................................................................................ 15 5. Tidal Datums................................................................................................................. 17 6. Station Descriptions ...................................................................................................... 21 7. Acknowledgements ....................................................................................................... 21 8. References ..................................................................................................................... 21 SECTION 2: NGS DATA SHEETS ............................................................................................. 23 SECTION 3: ADDITIONAL DATA SHEETS .......................................................................... 229 SECTION 4: NGS REPORT OF HORIZONTAL CONTROL AND VERTICAL COMPUTATIONS........................................................................... 239 SECTION 5: THE IMPACT OF GEOID99 ON THE CONTROL NETWORK....................... 263 iii iv LIST OF FIGURES Figure Page Fig. 1. The Columbia River littoral cell extends 165 km from Tillamook Head, Oregon, north to Point Grenville, Washington and includes portions of Grays Harbor, Pacific, and Clatsop counties........................................................... 1 Fig. 2. Regional overview of the Washington Coastal Geodetic Control Network with primary and local network stations identified. Names shown in this figure are for the nine High Accuracy Reference Network stations within the network.....................................................................................................................2 Fig. 3. Map showing the location of network stations within Grays Harbor County, Washington.............................................................................................................. 6 Fig. 4. Map showing the location of network stations within Pacific and Wahkiakum County, Washington ........................................................................... 7 Fig. 5. Map showing the location of network stations within Clatsop County, Oregon..................................................................................................................... 8 Fig. 6. Estimated (!) and actual (♦) MHW and MLW elevations for the tidal stations within the Columbia River littoral cell. Dashed lines show the 95% confidence interval of the equations used to calculate the estimated MHW and MLW values ................................................................................................... 20 Fig. 7. WCGC project control and primary base network.............................................. 249 Fig. 8. WCGC local network.......................................................................................... 250 v vi LIST OF TABLES Table Page Table 1. Coordinates for the seventy-six stations contained within the Washington Coastal Geodetic Control Network in the Washington State Plane South, meters, NAD 83 and NAVD 88 coordinate systems............................................. 12 Table 2. Coordinates for six stations tied to the network but not adjusted by the NGS in the Washington State Plane South, meters, NAD 83 and NAVD 88 coordinate systems ................................................................................................ 14 Table 3. Estimated centimeter level elevations for the twelve Oregon stations. Estimated elevations based on the regional GEOID96 correction factor are shown in bold text (values in meters).............................................................. 17 Table 4. NAVD 88 elevations for tidal benchmarks located throughout the Columbia River littoral cell (values in meters)...................................................................... 18 Table 5. Predicted NAVD 88 elevations for five first order Washington benchmarks as calculated with GEOID96 and GEOID99. The difference between the predicted elevations obtained with GEOID96 and GEOID99 are shown in the last column. All elevations are in meters ...................................................... 266 Table 6. Predicted NAVD 88 elevations for five first order Oregon benchmarks as calculated with GEOID96 and GEOID99. The difference between the predicted elevations obtained with GEOID96 and GEOID99 are shown in the last column. All elevations are in meters ...................................................... 266 Table 7. Comparison of GPS derived NAVD 88 elevations for seven stations in northwest Oregon. Elevations shown are published (NGS), predicted with GEOID96 using the Washington 0.14 m correction factor, and predicted with GEOID99 using the Oregon 0.03 m correction factor. All elevations are in meters ........................................................................................................ 267 vii viii SECTION 1: THE WASHINGTON COASTAL GEODETIC CONTROL PROJECT 1. Background Information The Southwest Washington Coastal Erosion Study is a multidisciplinary effort aimed at measuring, describing, and modeling the natural and human factors that impact the shorelines of the Columbia River littoral cell (Kaminsky et al. 1997). The littoral cell is 165 km in length and extends from Point Grenville, Washington in the north, to Tillamook Head, Oregon in the south (Figure 1). To measure temporal and regional variations within this highly dynamic system, a beach morphology monitoring program has been implemented to document short- to medium-term shoreline variability (event – seasonal – annual scale) within the littoral cell (Ruggiero et al. 1998; Ruggiero et al. 1999). The monitoring program utilizes Global Positioning System (GPS) technologies to obtain sub-decimeter measurements of beach change at sampling sites distributed throughout the study area. To obtain the sub-decimeter accuracy’s required by this monitoring effort, a high precision vertical and horizontal control network was developed (Kaminsky et al. 1998). This geodetic network supports the use of both real-time-kinematic (RTK) and geodetic GPS survey technologies. The network has been designed to support data collection and provide a common reference datum and coordinate system for the multiple agencies involved in the study. The geodetic control network supports quantitative shoreline mapping, topographic and bathymetric surveying, surface elevation modeling, aerial photo orthorectification, ground-truthing of remote sensing operations, and a multitude of local uses, including point positioning and feature delineation. Figure 1. The Columbia River littoral cell extends 165 km from Tillamook Head, Oregon, to Point Grenville, Washington and includes portions of Grays Harbor, Pacific, and Clatsop counties. 1 The geodetic control network described here, was developed by the Washington Department of Ecology (Ecology) with assistance from the National Geodetic Survey (NGS), US Geological Survey (USGS), Washington Department of Transportation (WS DOT) and the US Army Corps of Engineers (COE). The design process involved the identification, description, retrieval, and field recovery of over 140 survey markers within the region. Of the existing survey markers, 62 were selected for inclusion in the network and 14 new survey markers were installed. The seventy-six stations shown in Figure 2 comprise the Washington Coastal Geodetic Control (WCGC) Network. Figure 2. Regional overview of the Washington Coastal Geodetic Control Network with primary and local network stations identified. Names shown in this figure are for the nine High Accuracy Reference