Wave runup 



Wave runup on the face of the St. Paul Harbor main breakwater was obtained 

 with a videotape system. This technique has been used previously to measure runup 

 on beach slopes, but was modified to secure breakwater runup for St. Paul. A video 

 camera was set up and mounted on the cliff south of, and overlooking, the harbor 

 (Figure 17). Four ground control points (GCP) along the breakwater crest and two 

 profile locations (PFL) along the breakwater face were estabhshed as shown in 

 Figure 1 8. The x, y, and z coordinates of the camera location, the center of the 

 GCPs, and points along the PFLs then were determined to establish the required 

 geometry. By using the GCPs as control and knowing the profile, a time series of 

 wave runup was generated. The surface of the water on the structure was digitized 

 six times per second along the breakwater PFLs. Digitization was completed from 

 videotape. The data can be retrieved, displayed on a monitor, and analyzed for 

 runup time series. This technique has the advantages of being low-cost, logistically 

 simple, and providing relatively accurate measurements. More information on 

 obtaining wave runup through videotaping techniques may be found in Hathaway, 

 Howd, and Oltman-Shay (in publication). 



Figure 17. Video camera used to obtain runup data 



WES personnel were onsite and obtained videotape footage during the mid- 

 October through mid-December 1994 time period. The camera was mounted and 

 connected to a recorder, and videotape footage was generally obtained twice daily 

 for 30-min durations. A log book was maintained during periods when the data 

 were collected. The videotapes were analyzed to secure wave runup time series and 

 subsequent vertical runup data. Data were initially generated for both PFLs, but 

 since they were in close agreement, only PFL 1 (the most shoreward profile) was 

 analyzed to decrease analysis time. Runup values reported are significant values 



Chapter 2 Monitoring Program 23 



