tide to correlate current velocity witii tidal stage, and the use of powder or dye to ensure 

 the water surface is opaque. A description of trials at three locations in the Bay of Fundy 

 includes three stereopairs showing the anomalous water surface and numerical examples 

 using data from one of the stereopairs. 



5203RS0002 



OROS, CHARLES N., "River Current Data from Aerial Photography," Photogrammelric 



Engineering, Vol. 18, No. 1, Mar. 1952, pp. 96-99. 

 Keywords: Aerial Photographs, Water Currents, Columbia River, Oregon 

 Report describes a study by the Corps of Engineers to determine river current velocity and 

 direction on a section of the Columbia River known as FivemUe Rapids for use as 

 background data to design the Dalles Dam. Photos of floating targets painted on a sheet of 

 plywood supported by two connected oil drums were used. The targets were released 

 upstream and their progress traced on overlapping photos. By comparing adjacent photos 

 taken at a known time interval, the velocity and direction of the target movement were 

 determined. Flights were planned at specific river stages when current data were desired. 

 Radio communications between boats releasing targets and a ground operaions base and 

 signal flag communications between the operations base and the aircraft coordinated 

 operations. Satisfactory current data were obtained for a situation in which other methods 

 would have been almost impossible. Technique could possibly be modified for use in 

 measuring current velocity and direction in coastal engineering applications. 



5207RS0001 



WARD, H. A., "A Method of Separating Multiple Systems of Ocean Waves for Detailed 

 Study of Directions and Other Properties," The Bulletin of the Beach Erosion Board, 

 Vol. 6, No. 3, July 1952, pp. 1-13. 

 Keywords: Aerial Photographs, Wave Patterns. 



A procedure is described for using photos of nearshore areas to determine direction of 

 multiple ocean wave trains. Inadequacy of other methods of determining wave direction is 

 discussed. Improvements in wave refraction and longshore current calculations that may 

 result from collection of more reliable wave direction data are noted. The proposed 

 procedure can detect and analyze two or more systems of waves approaching the shoreline. 

 A transparent sheet with a series of parallel lines drawn at about 0.1-inch intervals is placed 

 over the photo and rotated to detect the wave systems. When the parallel lines are aligned 

 with the obvious series of wave crests, these lines cover the obvious wave system and permit 

 less obvious wave patterns to be observed. These minor wave systems are usually difficult or 

 impossible to detect on photos. Examples of the device and technique are included. 



