Mapping and Monitoring

Coastal Geologic Services Inc. provides mapping services for individual sites, such as for restoration design, and Sound-wide mapping projects — including the most up-to-date collection of coastal data for the region.

3D Mapping

To create 3D color surfaces for sites from 50 feet to a few miles long, CGS uses RTK GPS mapping, total station topography, and structure from motion photogrammetric scanning. This process uses hundreds of photos from a drone (UAV or UAS) to deduce the 3D shape of a beach and rapidly produce surface models and orthophoto mosaics with resolutions of 1–3 inches (about 2.5–7.5 centimeters). These cost-effective mapping methods enable accurate construction planning and baseline monitoring of beach conditions.

CGS has successfully used this technique:

  • to prioritize revetment repair along 5.5 miles of coast for the Lummi Nation (example 3D model below)
  • with sonar bathymetric surface mapping to plan dredge material reuse
  • for single-family soft shore project design in Island, Kitsap, and San Juan counties
  • for as-built and monitoring mapping of beach nourishment projects in Whatcom, San Juan, and Skagit counties
  • for concept-level eelgrass mapping in Whatcom County
  • to visualize sea level rise for no-bank property owners
  • to map steep bluffs where access is difficult or impossible

Historical Geomorphic Analysis

Example of shore change analysis showing bluff recession rates changing with shore orientation.

For other sites, historical shore change analysis can reveal long-term trends in geomorphic change. Our extensive collection of historical aerial photos — going back to the 1930s — is used with the USGS Digital Shoreline Analysis System to quantify change in shoreline position. Through historical analysis, we have collected the largest set of bluff recession rates for the region.


CGS has been monitoring our region’s coast since the company’s inception in 1993. From river deltas, eroding bluffs, barrier beaches and coastal wetlands, we have experience documenting physical changes in beach topography, bathymetry, volume, inlet dynamics, sediment composition, vegetation assemblages, and nearshore habitats such as forage fish spawning areas. We have quantitatively monitored beach restoration, beach enhancement, and estuary restoration project performance for over 20 years.

Monitoring storm damage to the revetment along Lummi Shore Road.