The second wave gage type was a newly developed directional wave gage, a 

 DWG. This sensor package consisted of three Paros Scientific piezoelectric 

 pressure sensors also mounted on a trawler-resistant seafloor pod Ln an 

 equilateral triangle distribution. This instrument is further described in 

 Howell (1992). Like the Puvs, the DWGs were self-recording. 



In all cases, pod orientation (necessary to determine wave direction) was 

 determined by divers following deployment and checked during retrieval. The 

 pod also contained a power source, data storage components, and an acoustic 

 transponder. Datasonic acoustic releasing transponders were used to assist in 

 locating the equipment pods for data retrieval and gage changeouts. 



The Puv's were programmed to collect hourly water level data (pressure and 

 temperature) and current data (velocity and direction) in 300-sec (5-min) bursts 

 at a 1-Hz sampling rate. Wave data (height and period) were collected every 

 3 hr in 2,048-sec bursts (approximately 34 min) at a 1-Hz sampling rate. Puv 

 data were recorded onto a magnetic cassette with a storage capacity that 

 permitted a deployment interval of about 6 months. When the instruments 

 were retrieved, the data tapes were removed. 



The DWG sampled output of the quartz pressure transducers at 1 Hz for 

 1,000-sec bursts (approximately 17 min) hourly. Recorded data from both the 

 Puv's and DWG were later downloaded to the CERC mainframe computer for 

 subsequent analysis. 



Initially, two Puv-instrumented pods were deployed in May 1990. 

 Approximately every 6 months, the pods were retrieved and the sensors 

 changed out. A total of six deployments were conducted, with the final 

 retrieval occurring in April 1994. Table 1 provides gage and deployment 

 information and Table 2 lists the wave data available by month. 



Two SEADATA Thermal Data Recorders (TDR's) were deployed in the 

 Colorado River near its mouth in May 1990 to collect tidal (water level) data. 

 The TDR's were programmed to collect data by averaging 1-Hz samples 

 continuously over a 450-sec (7. 5-min) interval. Attempts to locate the TDR's 

 during the second deployment in December 1990 were unsuccessful. It is 

 believed that the instruments were buried by sediments. No additional TDR's 

 were deployed in the river for the rest of the monitoring period. 



Short-term deployments 



Three intensive, short-term field experiments were conducted in May 1990, 

 July 1991, and January 1992 to obtain a comprehensive data set of current, 

 wave, and sediment transport measurements at the area of the jetty structures 

 and impoundment basin. This section provides an overview of the equipment 

 and procedures used during those experiments. 



Data collection during the short-term experiments consisted of simultaneous 

 field measurements of currents, sediment transport, and bathymetry to provide 



1 2 Chapter 3 MCCP Monitoring Plan and Implementation 



