ICF Jones & Stokes 5/4/2017 - Laserfiche WebLink

Year i0 Monitoring ofthe_Smith Island/Union Slough Habitat Restoration Site I Everett Public Works Assumptions: • Task includes 4 rentals of hand-held water quality meter and canoe for high tide sampling access, which will be billed as a direct project expense 4. Sedimentation—documentation of surface elevations in mitigation site • Measure and record ground surface elevations at the 58 monitoring points originally established and surveyed in July 2008(Year s). Measurements will be taken using Real Time Kinetic(RTK)global positioning system(GPS)survey equipment with an anticipated sub-centimeter accuracy. During a period of low tide when most of the site's ground surface is exposed, ICF staff will walk to each monitoring point, occupy the point with the RTK GPS, and record elevation of the ground surface and horizontal coordinates at the point when the GPS system has appropriate satellite coverage and stability to obtain reliable information to the level of accuracy needed for the analysis. • Process collected data by downloading from the data collector and creating a point file in ASCII text format that can be imported to any typical CADD or GIS program. • Compare ground elevations at each point to the ground elevations measured at that point during Year a and Year 4 monitoring. Determine the amount of ground elevation increase or decrease from Year s to Year io and from Year 4 to Year ao. Create a set of figures using GIS. o The figures shall include a recent aerial photograph of the site for the background, and data from the ground elevation survey displayed at each monitoring point. The horizontal location of each monitoring point will be shown on the figures. o A minimum of three figures will be created; one figure will show Year io measured ground elevation at each point, one figure will show elevation change between Year a and Year 10, and one figure will show elevation change between Year 4 and Year 10. • Using the figures created in the previous subtask and field observations, identify trends in the ground elevation changes both spatially and temporally. To the extent practical, determine likely causes for the changes to ground surface elevation. • Summarize data collection methods used for this portion of the monitoring, show the Year so ground elevations in tables and figures, show the amount of change from Year a and Year 4 to Year io ground elevations in tables and/or figures, and explain possible or known reasons for the change. This work will become a section of the Year io Monitoring Report(Task 5). Deliverables: • There is no specific deliverable for this task. The information collected and results of the comparisons with Year a and Year 4 will be summarized in a section the report that is the Task 5 deliverable. Page 4 ICF