XV 



the a('C0Tiii)anyiTig cut, vvliich rep]*esents a fisliway dis- 

 charging a A'olnme of Avnter from 12 to IT) inches deep and 

 ten feet \vide. 



McDonald fishwa r, 



Showing \vorkin<i' at Icnv water stagre. 



For economy of wnter supply at low stages of water, 

 the middle section five feet in width is depressed bek)w 

 the plane of the sides, so that (mly this middle section 

 takes water when the riA-er is low. In full stages of 

 water the wliole breadtli of the hslnvay discharges. 



Fishways shonld always, wlien practicai^le, be.recessed 

 into tlie da-m, so that the discharge from the lower end 

 of the fishway will he on a lint^ with the lower face of the 

 dam. Where not practicable to recess the fishway as 

 indicated, tlien it sliould be ]ilaced next to the bank and 

 a sh)piTig ai>ron ])laced in the angle between the fishway 

 and the dam, so as to establish tin uninterrupted line of 

 ovei'fall from tlu^ month of tlic fishwav to the (hun. This 



