56 



Appendices to Semnteenth Annual Report 



is about a mile further up the river. The intake for the lade supplying 

 Gordon's Mill passes off from the right bank of the river immediately 

 above the curved part of the cruive dyke. During normal flow of the 

 river the upper water-level at the dyke is about ten or twelve inches 

 below the top of the dyke, and the dyke itself is only between three and 

 four feet above the level of the lower pool, so that, even including the 

 netting of the Lebby Pot as part of the cruive fishing, the structure is 

 not so serious as to be now described as the worst cruive obstruction in 

 Scotland, or by any means the worst obstruction in the river Don 

 (vide p. 8). 



4. In the Tay district, as has been shown by the above Table, two 

 cruives exist on the river Earn. The Dupplin dyke is about 200 yards 

 long, stretching obliquely across the river from bank to bank. In 

 vertical height it is about 10 feet. The one box is situated between 

 two small islands and is 10 feet wide. Owing to the steep gradient, 

 the height of the dyke, and the volume of water confined in the river 

 above the dyke, the current through the box is very great, so that ev^n 

 during the weekly and annual close times, when the hecks and inscales 

 are removed, fish cannot readily pass the dyke except during floods, 

 when they ascend over the face rather than through the box in the dyke. 

 To perrnit of a fair passage of fish, as is intended by the requirements 

 for the weekly slap, mentioned in all Acts referring to cruives, a salmon 

 pass would require to be erected by means of subsidiary dykes thrown 

 across the channel between the right bank and that portion of the 

 cruive dyke which is to the right of the cruive box. 



5. About eight miles further up the river, Strathallan cruive dyke 

 occurs. It is, at normal levels, about 5 feet high, but the face of the 

 dyke rises most abruptly. One box also causes a great flow of water, 

 but more passes over the sill of the dyke than at Dupplin, and the fall 

 :is not so great, hence the passage through the box is more negotiable 

 for ascending fish when that passage is passable. If the matter could 

 be arranged, however, great benefit would result to the sport of the 

 river if a salmon pass could be introduced. 



6. The only other cruive dyke which remains to be mentioned is that 

 on the Forth, at Craigforth, about a mile below the mouth of the Teith. 

 It is an example of the large type of cruive as found also at Dupplin 

 and Strathallan on the Earn. It measures 6 feet broad by 13 feet long. 

 A. view of it is given in Plate II. The long levers seen in the illustration 

 above the cruive box are used for raising the wooden blinds which shut off 

 the water when the fish are removed, or when the inscales are being 

 adjusted. One of the inscales can be seen in the photograph, the 

 blinds being up and the water flowing through the box. Entrance for 

 the fisherman is obtained by a wooden hatchway communicating with 

 iron steps fixed in the concrete wall. The box is supported against the 

 action of floods by heavy iron shores set in the stonework of the apron. 

 When the photograph was taken, the tide being out, the depth of water 

 at the sill of the box was 4 feet 3 inches. The current passing through 

 the box is, however, by no means heavy, and sea -trout and small salmon 

 should be able to pass through the heck in ordinary conditions of water- 

 flow. The objection applicable to both Dupplin and Strathallan cruives 

 is therefore not present at Craigforth. The weir is very long, is 

 /-shaped, and quite perpendicular, the water immediately below 

 being very shallow and broken. It varies in height owing to the 

 difference in level of the bed of the stream below. The highest point is 

 furthest down stream. I estimated the elevation to be between 8 and 

 9 feet, the tide being out. A view of the weir will be found in Plate 

 III. The cruive is near the left bank, where the dyke is 4| to 5 feet. 

 Near the right bank the rocky ledges, upon which the masonry is 



