Electrof ishing survey 30 May 1991 Page 10 



Another discouraging observation is the degree of sedimentation. It was 

 impossible to fish the exact locations sampled in the past at Ballard Island Chute and 

 Detweiller Marina because the boat became stranded. These 2 stations will have to be 

 abandoned and alternative sites picked for 1991. A third station, Turkey Island Chute, 

 changed from a deep to a shallow chute approximately 15 years ago, when it apparently 

 was filled with sandy dredge spoil. The on-site dredge spoil inspection teams will 

 probably avert another Turkey Island Chute. However, gradual filling of some of the 

 remaining side channels and backwaters will continue unless remedial action, such as 

 proposed for a few locations under the Environmental Management Program, is 

 undertaken. Hurricane and Diamond Island chutes in the lower Illinois River remain 

 deep and generally have good fish populations year to year. These chutes have a fairly 

 uniform width and moderate current velocity, and appear to be self-scouring. The same 

 design might be self-maintaining if copied in other parts of the river. 

 Jobs 4 and 5. Database 



Mr. Robert Illyes has made considerable progress at the Survey's main office in 

 Champaign on merging the historical data sets and making them available in an RBase 

 format that will run on an IBM PC. This has not been an easy task because the coding 

 differs markedly between the Starrett-Sparks data set and the set collected by Kenneth 

 Lubinski. During the past 15 years the mainframe computers and the software used for 

 data analysis at Champaign have changed at least twice, adding further incompatibilities 

 and complications. 



The historical data are being converted to coding and formats that are consistent 

 with this project (F-lOl-R), which began in 1989. 



Mr. Illyes is developing checking routines that will find obvious errors, such as a 

 1-inch fish that is listed as weighing 2 pounds, but it may still be necessary to complete 

 one more round of verification by laboriously checking printouts against the original 



