110 



Appendices to Twenty -second Annual Report 



The mouth or entrance to the pass — which is seen in the two first 

 photographs — is carried, at the gradient already mentioned, into the fall 

 pool, so that fish do not require to leap into the pass, as was the case in 

 their attempts to enter the old Invermoriston Ladder, but may swim 

 into and up the pass. The mouth is not appreciably nearer the fall 

 than is the mouth of the old ladder on the opposite side, but a very 

 considerable volume of water can be brought down the pass to influence 

 the fall pool — indeed, it appears that in low summer level with the pass 

 working, Invermoriston Fall will be materially reduced. The intake 

 of the pass is provided with three substantial sluices arranged to suit 

 different levels of water, the middle sluice being one foot higher in the 

 sill than the sluice on one side, and one foot lower than that on the 

 other side. A short arch of rock exists just below the sluices. For 

 the purpose of acting as breaks or stops to the force of descending water, 

 stones 36 inches long are sunk into the bed of the pass so as to project 

 20 to 24 inches. These stones — which may be noticed in the photo- 

 graph, taken from inside the dry pass looking down through the mouth 

 to the river below — are 14 inches broad and about 12 inches thick, and 

 are placed in rows at right angles to the sides of the pass, three stones 

 in a row with spaces of about 16 inches between each. From the 

 sluices to the first row of stones the distance is 20 feet, but for the rest 

 of the way down the pass rows of stones occur every 15 feet. 



From an inspection of the pass at a time when fish were running 

 through the pools below, I was satisfied that fish could, without 

 difficulty, ascend the easy gradient till the exit or upper end was 

 reached. Here, however, owing to the velocity of the river in the pool 

 above the fall, a difficulty presented itself, and I am of opinion that 

 some modification for the purpose of checking the force of water at the 

 sluices will have to be resorted to. 



The rock cutting has been attended with much difficulty, owing 

 largely to the high inclination at which the rocks are bedded. After a 

 great amount of work had been accomplished an unfortunate rock-slide 

 took place, a mass, estimated by the engineer as weighing 1150 tons, 

 dropping into the pass. This, coupled with the continually swollen 

 condition of the river during last summer, has greatly increased the 

 contractor's labours, but I am informed the work was accomplished in 

 time to permit late running fish making the ascent. 



W. L. Calderwood. 



