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HomeMy WebLinkAboutAppendix D Duck Survey Report Town of Duck, NC 2013 Hydrographic and Topographic Survey Coastal Planning & Engineering of North Carolina, Inc. Town of Duck, NC 2013 Hydrographic and Topographic Beach Survey Report Prepared for: Town of Duck Prepared by: Coastal Planning & Engineering of North Carolina, Inc., No. C-2331 4038 Masonboro Loop Road Wilmington, NC 28409 November 2013 Town of Duck, NC 2013 Hydrographic and Topographic Survey Coastal Planning & Engineering of North Carolina, Inc. TABLE OF CONTENTS Abstract Survey Methodologies Map Preparation Ground Digital Photography Survey Maps Survey Report Notes and Certification LIST OF APPENDICES Appendix No. 1 Monument Information Report 2 Profile XYZ data 3 Profile Plots 4 Ground Digital Photography 5 Field Book Pages Town of Duck, NC 2013 Hydrographic and Topographic Survey Coastal Planning & Engineering of North Carolina, Inc. ABSTRACT Coastal Planning & Engineering of North Carolina, Inc. (CPE-NC) was contracted by the Town of Duck to provide a hydrographic and topographic survey for the support of a beach nourishment project consisting of thirty-eight (38) profile stations ranging from Salt House Road in the community of Pine Island to 9th Avenue in the Town of Southern Shores. CPE-NC surveyors conducted the beach and hydrographic survey September 10, 2013 through September 16, 2013. The physical monitoring of Duck included Hydrographic and Topographic surveys of the beach and offshore areas. The monitoring data is necessary to observe and assess beach conditions to aid in the design of the beach nourishment project. Once a project is constructed, monitoring surveys are necessary to continually observe the performance of the nourishment project as well as assess effects of said project on adjacent shorelines. The scientific monitoring processes provide information necessary to plan, design, and optimize initial beach nourishment projects and future renourishment projects. The information gathered may potentially reduce the need for, and cost of, unnecessary work as well as potentially reducing any environmental impact that may have occurred or been expected. Town of Duck, NC 2013 Hydrographic and Topographic Survey Coastal Planning & Engineering of North Carolina, Inc. SURVEY METHODOLOGIES The beach profile surveys were conducted in accordance with the Minimum Performance Standards for the U.S. Army Corps of Engineers (USACE), Engineering and Design Hydrographic Surveying Manual (EM 1110-2-1003). This survey is in accordance with Chapter 56.1606 of the North Carolina Administrative Code (NCAC) specifications established by The North Carolina Engineering and Land Surveying Act (GS89C). All work was conducted under the direct supervision and responsible charge of a Professional Land Surveyor (PLS ) who is registered in the State of North Carolina. In addition, all hydrographic surveying was conducted under the direct supervision of an American Congress of Surveying and Mapping (ACSM) Certified Hydrographer (CH). A signed and sealed certification is provided at the end of this Hydrographic and Topographic Survey Report. Eight (8) maps are presented, one (1) project location map and seven (7) plan view maps. The plan view maps show reduced true position elevation data collected during the survey. The location of all published control, as well as control found and used for survey purposes, is presented in the Monument Information Report provided in Appendix 1. Vertical data was collected in the North American Vertical Datum of 1988 (NAVD88). All Horizontal data is provided in the North Carolina State Plane Coordinate System, North American Datum of 1983/2011 (NAD 83/2011). Profile data is presented in xyz format relative to NAVD88 in Appendix 2. Profile plots are provided in Appendix 3. Ground digital photography obtained during the survey is provided in Appendix 4. Copies of all field book pages are provided in Appendix 5. The field survey and data collection activities encompassed four (4) phases. Brief descriptions of each survey phase, including methodologies and quality control/quality assurance procedures, are described below. Phase One: Control Reconnaissance/Establishment/Verification Prior to the start of the survey, reconnaissance of the monuments was conducted to confirm that survey control was in place and undisturbed. Real Time Kinematic Global Positioning System (RTK GPS) was used to locate and confirm survey control for this project. The horizontal and vertical accuracy of control data meets the accuracy requirements as set forth in the Engineering and Design Hydrographic Surveying Manual (EM 1110-2-1003). In order to achieve required accuracy, the Hydrographic and Topographic surveys were controlled using 1st order monuments, specifically Caffey and Y254 from the National Geodetic Survey (NGS). Horizontal and vertical positioning checks were conducted at the beginning and end of each day using at least two 1st order monuments in the project area. The RTK GPS utilizes statistical methods to ensure accuracy of RTK GPS data remains within the 95% confidence interval. The control check shots were acquired using a minimum of five (5) epochs which results in a high accuracy location. Results from 1st order control checks are displayed showing northing, easting, monument elevation, inverses, horizontal and vertical root mean square error, location description and photographs as indicated in the Monument Information Report (Appendix 1). Town of Duck, NC 2013 Hydrographic and Topographic Survey Coastal Planning & Engineering of North Carolina, Inc. Phase Two: Beach Profiles Upon completion of the control reconnaissance survey, beach/upland and nearshore operations were initiated. Cross-sections of the beach in the project area were surveyed using extended rod RTK GPS rovers, standard RTK GPS rovers, and differential leveling techniques. Extended rod RTK GPS rovers were used to augment RTK GPS survey capability into the nearshore. The current systems allow surveyors from CPE-NC to collect the entire beach profile with RTK GPS technology. Incorporation of RTK GPS into monitoring surveys greatly reduces the potential for human error during data collection and reduction. Furthermore, RTK GPS provides accuracies of eight (8) millimeters + one (1) part per million with true horizontal positioning to the survey data point regardless of sea state. Profiles commenced from the onshore control point and extend seaward overlapping the offshore data. Nearshore portions of the profiles were surveyed by two (2) surveyors with an Extended Rod Trimble R8 RTK GPS rover who entered the water wearing Personal Floatation Devices (PFD). Trimble TSC3 data collectors are equipped with Bluetooth technology allowing wireless communication with the GPS receiver. The rover system allows surveyors from CPE- NC to reach a maximum water depth of eleven (11) feet. The nearshore survey extended seaward to a point overlapping the offshore portion of the profiles by at least fifty (50) feet. The upland portion of the survey commenced at the waterline and extended 150 feet landward of the vegetation line or until an obstacle was encountered. The upland portions of the profiles were surveyed using an RTK GPS. Elevations were taken at approximately twenty-five (25) foot intervals along each profile line and at all grade breaks. To maintain online accuracy surveyors utilized the RTK GPS feature stakeout point. Stakeout point allows surveyors to maintain the profile azimuth without relying on survey lathe or conventional compass bearings allowing surveyors to maintain a three (3) foot profile line variance. Phase Three: Nearshore/Offshore Profiles The Nearshore/Offshore profiles were conducted at each required profile station. The profiles were obtained from the surf zone seaward to an elevation no less than negative twenty- five (-25) feet NAVD88. The landward limits of the nearshore profiles were based on a minimum overlap of fifty (50) feet beyond the seaward extent of beach profiles. Soundings were collected at a maximum of twenty-five (25) foot intervals with an Odom Hydrotrac, sufficient to provide an accurate depiction of the seafloor. Nearshore/offshore profiles were collected using an Odom Hydrotrac single frequency sounder with digitizer on CPE-NC’s twenty-eight (28) foot Parker survey vessel with a centrally located hull-mounted transducer. Data was digitally stored using HYPACK Software. A Trimble R8 RTK GPS was used onboard the survey vessel to provide instantaneous tide and heave corrections. Manual tide readings were taken while conducting the onshore portion of the profile to verify onboard tide readings. In order to maintain the vessel navigation along the profile lines, HYPACK navigation software was used. This software provided horizontal position to the Town of Duck, NC 2013 Hydrographic and Topographic Survey Coastal Planning & Engineering of North Carolina, Inc. sounding data allowing real-time review of the data in plan view or cross-section format. HYPACK also provided navigation to the helm to minimize deviation from the online azimuth. Horizontal and vertical positioning checks were conducted at the beginning and end of each as described in phase one (1) of the survey. The sounder was calibrated via bar-checks and a sound velocity probe at the beginning and end of the day. The DIGIBAR PRO sound velocity meter offers a fast additional calibration for sound velocity as compared to the traditional bar - check. Bar-checks were performed from a depth of five (5) feet to a depth of at least twenty-five (25) feet. Analog data showing the results of the bar-check calibration was displayed on the sounder charts at five (5) foot increments during descent of the bar. Prior to start of each survey day the last profile line of the previous day was rerun to verify accuracy of the hydrographic data. Offshore data was collected within one (1) week of onshore data collection for each line. Nearshore and offshore data from profile stations D-20 through D23 were omitted due to the request from the Army Corps of Engineers Field Research Facility located in Duck, NC. Phase Four: Data Reduction/Submittals Upon completion of the field work, data was edited and reduced with HYPACK, Trimble Business Center, and CPE-NC’s internal software programs. The offshore raw digital data was viewed in HYPACK and a comma delimited file was created and exported to ArcGIS 10.1 for the availability to produce plan view plots. The offshore RTK GPS tide data that was collected was compared to the manually collected RTK GPS nearshore tide data, as well as observed and predicted tides for data verification purposes. The onshore and offshore data were merged and a representative cross-section was derived for each profile line. The cross-sections were developed using internal CPE-NC plotting programs. The final plots were reviewed with comparisons to previous years. The 2011 data used for comparison originated from 2009 upland data (landward of dune crest) obtained through LiDAR, 2011 upland data (dune crest to Mean High Water) obtained through LiDAR provided by the U.S. Army Corps of Engineers Field Research Facility (USACE FRF), and 2011 nearshore and offshore data (seaward of Mean High Water) obtained through bathymetric survey methods conducted by the USACE FRF. The September 2013 nearshore and offshore data used for comparison along profiles D-19 through D-23 (as shown in black on profile plots in Appendix 3) originated from a bathymetric survey conducted by the USACE FRF. The final approved cross-section data was prepared in the required formats for submittal (Appendix 2). Digital data is provided in the State required vertical datum NAVD88. Town of Duck, NC 2013 Hydrographic and Topographic Survey Coastal Planning & Engineering of North Carolina, Inc. MAP PREPARATION: Upon completion of the surveys and data reduction, the survey maps were prepared in ArcGIS 10.1. In order to avoid congestion, the survey maps do not show all of collected elevations but enough to give an accurate depiction of the cross sections. The survey maps display profile data and control monument locations plotted against National Agriculture Imagery Program (NAIP) 2012 aerial photographs. GROUND DIGITAL PHOTOGRAPHY: Surveyors from CPE-NC collected three (3) digital photos at a mid-beach location at each profile location. The three (3) photos included one (1) in each shore-parallel direction and one (1) landward toward the dune or upland area. Town of Duck, NC 2013 Hydrographic and Topographic Survey Coastal Planning & Engineering of North Carolina, Inc. SURVEY REPORT NOTES AND CERTIFICATION Survey Title: Town of Duck, NC 2013 Hydrographic and Topographic Survey Prepared Date: November 2013 Prepared For: Town of Duck Prepared By: Coastal Planning & Engineering of North Carolina, Inc. Dates of Survey: September 10, 2013 through September 16, 2013 Survey Location: Town of Duck (PI-17 through SS-02) Notes: 1. The survey is neither valid nor complete without both the survey report and described survey maps. Digital data files encompassing the following have also been provided in the following formats listed.  Monument Information Report (Appendix 1)  ASCII file (profile xyz data). Digital only (Appendix 2)  Profile Plots (Appendix 3)  Ground Digital Photography (Appendix 4)  Project field book pages. Digital only (Appendix 5) 2. Survey map and report or the copies thereof are not valid without the original signature and seal of a Professional Licensed Surveyor. 3. The information on this map represents the results of the survey on the dates indicated and can only be considered as indicating the general conditions existing at the time. 4. Additions or deletions to survey maps or report by other than signing party or parties is prohibited without written consent of the signing party or parties. 5. The coordinates shown are in US survey feet based on the vertical and horizontal data that was collected and presented relative to the North American Vertical Datum of 1988 (NAVD88) and the North Carolina State Plane Coordinate System, North American Datum of 1983/2011 (NAD83/2011). Town of Duck, NC 2013 Hydrographic and Topographic Survey Coastal Planning & Engineering of North Carolina, Inc. 6. Vertical measurements are based on first order monuments Caffey, 865 1370 C Tidal, 865 1370 D Tidal, 865 1370 K Tidal, C255, and Y254 per published NGS coordinates. 7. Bearings are based on a bearing of South 22°10’37” East between NGS monuments Caffey and Y254 per published NGS coordinates. 8. Underground and subaqueous improvements and/or utilities were not located as part of this survey and should be field verified prior to any dredging or construction activities. 9. Refer to CPE-NC field book No. 481 for the onshore portion and CPE-NC Navbook No. 41 for the offshore survey. 10. Aids to navigation were not located during this survey. 11. Soundings were collected using an Odom Hydrotrac, Single Frequency, survey grade sounder. The sounder was calibrated prior to the start of the survey following manufacturers recommended procedures. 12. This survey was conducted for the Town of Duck for use as a Hydrographic and Topographic survey. Certification: I, Jim Sullivan, certify that this project was completed under my direct and responsible charge from an actual survey made under my supervision; that this Hydrographic and Topographic survey was performed at the 95 percent confidence level (2 sigma) to meet Federal Geographic Data Committee Standards; that the horizontal accuracy is 0.010, that the vertical accuracy is 0.042 and that the original data was obtained on September 10, 2013; that the survey was completed on September 16, 2013; all coordinates are based on NAD83/2011; and all elevations are based on NAVD88. _____________________________________________ ________________________ Jim Sullivan Date North Carolina Professional Land Surveyor No. L-5064 Coastal Planning & Engineering of North Carolina, Inc., No. C-2331 2481 Northwest Boca Raton Blvd., Boca Raton, FL 33431 Town of Duck, NC 2013 Hydrographic and Topographic Survey Coastal Planning & Engineering of North Carolina, Inc. APPENDIX OVERVIEW 1) Monument Information Report Data collected during the surveys is entered in a spreadsheet format and compared to data provided by NGS. This comparison shows differences in northings, eastings and elevation of NGS published control, what was collected in the field, and what was used during profile reduction. 2) Profile XYZ data (digital only) Offshore survey data was converted into CPE-NC files. Onshore data was reduced by standard means of reduction and also entered into CPE-NC format and merged with the offshore data. CPE-NC format is used for in-house plotting, volume computations and other engineering analyses. The CPE-NC formatted data was converted into xyz format. The xyz data is provided in the datum collected NAVD88 as per state standards. 3) Profile Plots Profile plots of this survey data compared with historical profile data. 4) Ground Digital Photography CPE-NC surveyors collected three (3) digital photos at a mid-beach location at each profile location. The three (3) photos included one (1) in each shore-parallel direction and one (1) landward toward the monument. In addition, wherever possible a digital photo was taken of the control identification or stamping on the monument. 5) Field Book Pages (digital only) This appendix includes copies of the field book pages used for the survey. Refer to CPE-NC field book No. 433 for the onshore portion. Navigation field book No. 41 for the offshore survey.