turbidity of p. p. m. On the next day the water on 

 the west side of the Central Avenue dock gave an 

 84 percent oxygen saturation at the surface, 80 per- 

 cent at the bottom, free carbon dioxide, and a tur- 

 bidity of 20 p. p. m. On the following day the water 

 on the east side of the dock was 91 percent oxygen 

 saturated. 



The results of the analyses of the water of 

 Dunkirk Harbor show that critical conditions did not 

 exist. The extent of the influence of the sewage was 

 limited as it was dissipated in less than a mile of 

 lake water. If critical conditions did exist at any 

 point, they were restricted to the immediate vicinity 

 of the sewer outfalls. The activity of the extensive 

 weed beds seemed to counteract the effect of the 

 sewage during the summer months. Critical condi- 

 tions will develop, however, when the activity of 

 the water weeds and algae decreases, since all fac- 

 tors tending to produce such conditions are operative. 



The sludge deposits, in addition to rendering 

 the shore unsightly, have probably ruined a good 

 part of the spawning grounds lying in this naturally 

 protected harbor. 



Stations 11 and 12, and Port Dover 



Station 11 lay directly in line with the flow 

 from the mouth of Canadaway Creek, which empties 

 the effluent of the Fredonia sewage disposal plant 

 into the lake. Station 11 never varied from normal, 

 however, although Canadaway Creek was reported 

 to be polluted. 



Station 12 was off the mouth of Chautauqua 

 Creek, which flows by Westfield. Although surface 

 samples taken at this station were normal at all times, 

 the bottom samples yielded results indicative of pol- 

 lution. These abnormal results were due, however, 

 to a layer of cold water which extended into this re - 

 gion throughout the summer. This phenomenon will 

 be further discussed later. 



At Port Dover small fluctuations in oxygen and 

 chloride results indicated the presence of slight pol- 

 lution, but the effects are of no importance, for the 

 substances which would cause trouble are soon dis- 

 seminated in the lake. 



Erie 



The water of the enclosed harbor at Erie has a 

 very deep color due to its organic content. This 

 color is so deep that the water appears to be black 

 when viewed through a considerable depth. 



On the June cruise of the Shearwate r conditions 

 were normal at station 26, which was 5 miles di- 

 rectly off Erie. In Erie Harbor a sample was taken 

 at the Anchor Coal Company's dock. This dock lies 

 at the head of the first slip east of the Pennsylvania 

 elevator. The water here was in bad condition, but 

 the sample was not representative of general harbor 

 conditions. 



On the August cruise, 3 samples were obtained 

 in the harbor at Erie, 2 outside the harbor, and 1 at 

 station 26. The first sample was taken along the 

 south shore of the harbor, about 200 feet east of the 

 public steamboat landing. The water was very dark 

 in color and contained much suspended matter; the 

 Secchi disc reading was 2. 1 meters. Gas bubbles 

 rose continuously through the water. The second 

 sample was taken in the open harbor about 100 yards 

 south of red buoy No. 8. The third was taken in the 

 ship channel about 150 yards west of the harbor en- 

 trance. 



The first sample taken just outside the harbor 

 was collected at black buoy No. lA. The second 

 outside sample was taken 2 days later at the black 

 gas buoy No. 1. The water at this buoy was dirty 

 brown in color, because of the great amount of sus- 

 pended matter. On the same day sludge floated on 

 the surface of the harbor from the red buoy No. 8 

 to the harbor entrance. This material was brought 

 to the surface by the heavy shipping activity of the 

 previous day. When struck by waves the clumps of 

 sludge broke up, forming an inky suspension in the 

 water. 



A sample taken at station 26 on the same day 

 showed normal conditions for the open lake surface. 

 The results of the analyses of the harbor samples are 

 plotted in figure 41. In September, station 26 was 

 normal on the ninth. On the twelfth the harbor water, 

 after thorough mixing for 2 days by a strong westerly 

 wind, showed an oxygen saturation of 76 percent, a 

 chloride content of 15. 3 p. p. m. , a pH of 7. 6, and 



115 



