SUMMA.RY OF OBSERVATIONS IN OYSTER PRODUCING AREAS IN LOUISIA:iA AFFECTED 

 BY THE OPENING OF THE BONNET CARRE SPILLKAY FEBRUARY 1950 



INTRODUCTION 



The Bonnet Carre Spillvm.y was opened on February lO^ 1950 vhen 

 the stag© of the River at the spillway was 19o9 feeto The danger 

 level was listed as 20 feetj and the drain through the spillway was 

 expected to control the flood crest and relieve the city of New Orleans© 



The Louisiana Department of Wildlife and Fisheries requested the 

 Uo So Fish and Wildlife Service to survey the oyster beds which may be 

 affected by the outflow of Mississippi River flood waters through the 

 Bonnet Carre Spillway and Pearl River drainageo 



During the period February 11 through 2 3j, field and laboratory 

 work was conducted jointly with Dr<. Ho Malcolm Owen and Mr© Lester Lo Walters 

 of the research section of the Division of Oysters and Water Bottoms, Louisiana 

 Departeient of Wildlife and Fisheries^ and Mr© William Eo Shell, Corps of Engineers _ 

 Uo So Armyo Dro Owen furnished salinity and sediment data for the period after 

 February 24o 



CON DITIONS AT rm SPILLWAY AMD IN LAKE PONTCHARTRAIN 



The flow of flood water into Lake Pontchartrain was not very rapid at 

 firsto The advance of the river water, distinguished from the green of the 

 Lake by the red color of the suspended Mississippi mud, was traced from the 

 airo The only evidence of infiltration on February 11 was at the immediate 

 entrance of the floodway into the Lakeo In 10 days the river water traversed 

 easterly one=>half the length of the Lake and reached the eastern extremity by 

 the end of Februaryo 



A water sampling station was established at the New Orleans Airport on the 

 south shore of the Lake on February 11 for observing daily salinity and sediment 

 changes o Analysis of these samples is recorded in Table lo 



The drop in salinity between February 12 and 15 indicated a possible 

 influence of the fresh water inflow from the Mississippi River© The fact 

 that it Irield constant for the period of a week after February 12 demonstrated 

 that tha Lake was fresher but the inflow was slowo Full displacement of 

 salt laike water, however, was accomplished by March 5o The color of the 

 water on February 20, the data of my last airview of the Lake, was still 

 more green than red at the poiat of sampling statione 



Th© office of th© District Engineer, New Orleans District, Corps of 

 Engineers, Uo So Army, furnished weekly preliminary results of Discharge 

 Observations, Bonnet Carre Spillway, at th© Highway Bridge© The record 

 showed a slow but steady increase in the rate of discharge of water through 



