Please use this identifier to cite or link to this item:
Title: Estuarine processes and intertidal habitats in Grays Harbor, Washington : a demonstration of remote sensing techniques
Authors: Gatto, Lawrence W.
Keywords: Aircraft photography
Ground truth data
Data acquisition
Intertidal habitats
LANDSAT imagery
Remote sensing techniques
Grays Harbor, Washington
Water surface circulation
Publisher: Cold Regions Research and Engineering Laboratory (U.S.)
Engineer Research and Development Center (U.S.)
Series/Report no.: CRREL report ; 78-18.
Description: CRREL Report
Abstract: The primary objective of this project was to demonstrate the utility of remote sensing techniques as an operational tool in the acquisition of data required by the U.S. Army Corps of Engineers, Seattle District, in the Grays Harbor dredging effects project, and related projects. Aerial imagery was used to map surface circulation and suspended sediment patterns near the hopper dredge pump site at the harbor entrance and near pulpmill outfalls in Aberdeen, and to map the areal distribution and extent of intertidal habitats. The surface circulation maps prepared from the aerial photographs and thermal imagery compared favorably with the large-scale circulation patterns observed in the Grays Harbor hydraulic model at the U.S. Army Engineer Waterways Experiment Station. Of the imagery provided by NASA, the thermal imagery was more useful than the color or color infrared (CIR) photographs for mapping circulation, while the CIR photographs were more useful than the thermal imagery or the color photographs for mapping intertidal habitats. Current velocities estimated from dye dispersion patterns and drifting dye drogues were comparable at some locations to velocities measured by in situ current meters and in the hydraulic model. Based on a cursory evaluation of LANDSAT-1 imagery acquired in January, February, and October 1973, it had limited utility in providing data on surface circulation patterns in Grays Harbor. The areal distribution and extent of nine wetland vegetation types, dune vegetation, and three types of eelgrass were mapped using primarily aerial CIR photographs and ground surveys. Color photographs were also used for areas not covered by the CIR photographs. Wetland vegetation types mapped were: low silty marsh, low sandy marsh, sedge marsh, high immature marsh, high mature marsh, salt marsh, diked pasture, freshwater marsh, and wooded swamp. Undiked salt marsh (first five types) covered 5540 acres (22.3 km^2) in Grays Harbor. Dominant salt marsh plants include 𝑻𝒓𝒊𝒈𝒍𝒐𝒄𝒉𝒊𝒏 𝒎𝒂𝒓𝒊𝒕𝒊𝒎𝒖𝒎, 𝑺𝒂𝒍𝒊𝒄𝒐𝒓𝒏𝒊𝒂 𝒗𝒊𝒓𝒈𝒊𝒏𝒊𝒄𝒂, 𝑫𝒆𝒔𝒄𝒉𝒂𝒎𝒑𝒔𝒊𝒂 𝒄𝒂𝒆𝒔𝒑𝒊𝒕𝒐𝒔𝒂 , 𝑪𝒂𝒓𝒆𝒙 𝒍𝒚𝒏𝒈𝒃𝒚𝒆𝒊, and 𝑫𝒊𝒔𝒕𝒊𝒄𝒉𝒍𝒊𝒔 𝒔𝒑𝒊𝒄𝒂𝒕𝒂. The eelgrass beds mapped were 𝒁𝒐𝒔𝒕𝒆𝒓𝒂 𝒏𝒐𝒍𝒕𝒊𝒊 (narrow-bladed), "dense" 𝒁. 𝒎𝒂𝒓𝒊𝒏𝒂 (broad-bladed) and "sparse" 𝒁. 𝒎𝒂𝒓𝒊𝒏𝒂. "Dense" and "sparse" 𝒁. 𝒎𝒂𝒓𝒊𝒏𝒂 covered 5540 (22.3 km^2) and 5450 acres.(22 km^2), respectively, in 1975; 𝒁. 𝒏𝒐𝒍𝒕𝒊𝒊 covered 680 acres (2.74 km^2). Most eelgrass occurred in North Bay. However, "dense" 𝒁. 𝒎𝒂𝒓𝒊𝒏𝒂 beds were significant on both Mid-Harbor Flats and Whitcomb Flats. 𝒁. 𝒏𝒐𝒍𝒕𝒊𝒊 also occurred along South Channel and west of John's River. 𝒁. 𝒏𝒐𝒍𝒕𝒊𝒊 occurred at much higher intertidal elevations than did 𝒁. 𝒎𝒂𝒓𝒊𝒏𝒂, forming a band of vegetation between lower 𝒁. 𝒎𝒂𝒓𝒊𝒏𝒂 and higher salt marsh vegetation. The substrate where the 𝒁. 𝒏𝒐𝒍𝒕𝒊𝒊 is found is usually softer with more silt and loam than the substrate where 𝒁. 𝒎𝒂𝒓𝒊𝒏𝒂, which is firmer with predominantly sand, is found. In spite of the limitations of remote sensing techniques, they have important advantages compared with ship surveys. Based on project requirements, remote sensing techniques should be considered reliable tools to augment conventional data acquisition techniques in operational Corps of Engineers projects.
Rights: Approved for public release; distribution is unlimited.
Appears in Collections:CRREL Report

Files in This Item:
File Description SizeFormat 
CR-78-18.pdf7.85 MBAdobe PDFThumbnail