8 



Appendices to Seventeenth Annual Report 



number of years, is maintained by a check-dyke, a structure which, 

 unless explained in some very special way, seems to me to be illegal, 

 and concerning which I have entered into communication with the Don 

 District Fishery Board. 



Immediately below the cruives the tail lade of the Grandholm. Mills — 

 a cloth manufactory — on the left bank, enters and swells the water of 

 the Lebby Pot. This lade is about a mile in length, and contains a 

 large amount of water. In this mile the fourth mill occurs— Messrs. 

 Pirie's rag mills — but the water for this mill is led off on the right bank 

 by a long lade starting from a dyke about 200 yards above that which 

 gives water to the Grandholm Mills, so that the cruive and clam-dyke 

 at Gordon's Mill is deprived of water by the very long lade of the 

 Grandholm Mills alone Some advantage is gained by the length of 

 the lade to the last-mentioned mills — a substantial structure cut through 

 rock for a great part of its course — in that the dam-dyke at the upper 

 sluices is low, and offers no great obstacle to the ascent of salmon. 

 The same may be said of the dy*ke supplying Woodside rag mills, 

 although, unlike the Grandholm Mills, these are close to the 

 river. It is built, like the dam at the Kettoch Mill, with an up- 

 stream angle, and in addition, a broad race passes off close to the left 

 bank and enters about a hundred yards lower down without any obstruc- 

 tion, so that by this race salmon could pass up stream without ascending 

 the dam. An example of the effect of a too short lade is seen at the next 

 or Mugiemoss Mill — Messrs. Davidson's paper mill. The dyke here has 

 become notorious as an obstruction to the ascent of salmon, and during 

 last close season the fish had to be netted out of the pool below, and 

 conveyed (in the water-carts of Aberdeen) to the river some distance 

 above. This Mugiemoss Dam is referred to by Mr. Young in his 1st, 

 8th, and 9th Reports, and more briefly by Mr. Archer in the 1 1th 

 Report. Several modifications have from time to time been made on 

 this dyke in order to facilitate the ascent of salmon, but the obstruction 

 is still most formidable. In my opinion no slight modification will here 

 be of much avail, and unless a radical remodelling is undertaken, any 

 improvements in other parts of the river will suffer if (and the ample 

 supply of pure water must be considered of paramount importance) the 

 increased distribution of migratory fish so much needed for the improve- 

 ment of the general fisheries of the river be not facilitated at Mugie- 

 moss. 



At the time of my inspection, owing to a sudden reduction in the 

 water-flow, due presumably to the opening of mill sluices further up, 

 Mugiemoss dyke was deprived of much water (the state of the river 

 had been previously estimated as six inches above normal). By wading, 

 I was therefore enabled to make a thorough examination of the whole 

 structure. 



The down-stream face of the dyke is roughly elliptical in contour, a 

 straight salmon pass exists down the centre of the dyke, and at the foot 

 of this pass, between the side arms of the dyke, a long flat apron extends. 

 The outline of the apron is necessarily also elliptical; it is rendered 

 perfectly smooth by cement, and is the most singular feature of the 

 obstruction. The height of the dyke from the flat surface of the apron 

 is about 8| feet, and the length of the down-stream face, as measured 

 down the side of the pass, is 45 feet. This measurement also represents 

 the length of the pass, the breadth of which I found to be 5 feet, the 

 depth about feet, the floor being roughly rounded throughout ; and 

 the depth at the sill 18 inches. No breaks or stops exist, and therefore, 

 although measuring from the sill to foot of pass, the gradient is one in 

 five — the minimum recognised by Schedule G of the Salmon Fisheries 

 (Scotland) Act, 1868 — the length of the pass is such that the descend-- 



