PEARLY FRESH-WATER MUSSELS SI 



SESSIONAL PAPER No. 38a 



PEARLS. 



A considerable number of pearls and slugs are also found. Some are of very fair 

 size and good quality. In Mr. Clark's opinion, pearling alone would insure a suiEcient 

 return for one's labours if followed up. The highest figure yet obtained for a pearl 

 was $75. 



RECOMMENDATIONS. 



In order to develop to the fullest extent the resources of the river, three main 

 steps are urgent; first, to insure against depletion of the present stock of clams; 

 second, to restock and stock artificially all favourable areas, and third, to improve the 

 river in general by stream regulation. Since the last-mentioned object is so funda- 

 mental, I shall deal with it first. 



' STREAM REGULATION" AND SOME OF ITS ADVANTAGES. 



Through the progressive removal of the natural physical conditions regulating 

 stream-flow, the floods in the river have for some years been becoming more and more 

 violent and destructive. This increased flood-flow has naturally reduced the volume 

 of low water-flow proportionately. These two conditions, along with the scouring and 

 general damage of river-bed, constitute an increasing menace to mussel life, to 

 fisheries, and to power development along the river. 



Some idea of the truth of the above statements may be deduced from a study of 

 the following table of volume of flow at different points. The maximum flow of 

 greatest recent flood is also included. This took place in the spring of 1912. 



Approximate flow in cubic feet per second, period 1914, 1915 and 1916. 



* Maximum flows are mean of two gauge heights, tak-n a.m. and p.m. daily. Minimum flow s in 



some stations consist of leakage from dams. 



The danger consequent upon these conditions camiot readily be overestimated. 

 The fact that drainage areas of the Grand River and Great Miami river flowing through 

 Dayton, Ohio, are approximately equal, is sufficient proof. No doubt far-reaching 

 measures for the prevention of dangerous floods will have to be taken in the future. 

 If such measures involve water conservation, the resources of the river will be enorm- 

 ously increased. 



In the fall of 1912 the Hydro-electric Power Commission made a reconnaissance 

 survey of the river watershed covering the main stream from Caledonia to the head- 

 waters ; also of the larger tributaries from their confluence with -the main stream to 

 their headwaters. In this survey, the main object of which was to ascertain what 

 locations, if any, merited examination as sites for storage reservoirs and regulating 

 works, it was found that by the building of nine dams ranging from 30 to 65 feet, 

 storage reservoirs ranging from 450 acres to 3,000 acres in area could be obtained; the 

 aggregate acreage being between ten and eleven thousand. While the above figures 



