of the Fishery Board for /Scotland. 



61 



At the option of the millers or manufacturers, this provision may be 

 carried out either by shutting the sluice or sluices at the intake of the lade, 

 or by raising the banks of the lade to a height that will prevent an overflow 

 of water from the lade when the sluice at the wheel and the bywash sluice 

 hereinafter mentioned are both kept shut. Provided always, that the said 

 bye-law shall not apply to millers or manufacturers when taking measures 

 necessary for the protection of their premises during heavy floods, or when 

 rivers are cumbered with ice, or while necessary repairs are being executed 

 on any emergency, provided that notliing be omitted or done unnecessarily 

 to defeat the objects of this bye-law. Furthermore, in all cases when the 

 intake sluice is more than 300 yards from the water wheel, it shall not be 

 imperative to shut the intake sluice, or to keep the bywash sluice shut, 

 during ordinary meal hours, or during any stoppage of the wheel not ex- 

 ceeding an hour at a time. 



3. At the intake of every lade there shall be placed and constantly kept 

 a heck or grating for each opening, or one embracing the whole openings, 

 the bars to be not more than three inches apart, if horizontal, and not more 

 than two inches if vertical. 



4. A similar heck or grating shall be placed and constantly kept across 

 the lade or troughs immediately above the entrance to each mill wheel. 



5. A similar heck or grating shall be placed and constantly kept across 

 the lower end of each tail lade at its entrance into the main river. 



Note. — To prevent any obstruction to the flow of the water by the hecks 

 or gratings in the lades, it is recommended that the lade shall be in- 

 creased in width where the hecks are placed, and that the heck, 

 instead of being in a straight line across, should be curved or pointed 

 up or down stream, and thereby increased in length, so that the aggre- 

 gate of the openings between the bars shall exceed the sectional area 

 (or waterway) of the lade, and thus compensate for the space occupied 

 by the bars. 



6. There shall be a bywash sluice placed as near as practicable aljove 

 each water wheel in the embankment of the lade, of not less than three 

 feet in width, with its sill as low as the bottom of the lade, and the said 

 sluice shall be raised to a height suflficient to allow the smolts to descend 

 for at least five but not exceeding eight hours each week from the 15th 

 March to the 1st July, not more than six days intervening between eacli 

 time of opening. 



There shall be a salmon pass or ladder on the down stream face of every 

 dam, weir, or cauld, capable of affording a free passage for the ascending 

 fish at all times when there is water enough in the river to supply the 

 ladder. The width shall not be less than four feet in the clear in rivers of 

 less than 100 feet in breadth at the site of the dam, nor less than five feet 

 in breadth in rivers of less than 200 feet and more than 100 feet in breadth 

 as aforesaid, nor less than six feet in breadth in rivers of more than 200 feet 

 in breadth as aforesaid ; the upper sill shall be not less than six inches be- 

 low the lowest part of the crest of the dam for the whole width of the 

 ladder ; the inclination shall in no case be steeper than five horizontal to 

 one perpendicular, but w^herever practicable, shall be seven or eight hori- 

 zontal to one perpendicular, and in all cases shall be provided with breaks 

 or stops placed at suitable intervals, so as to lessen the velocity of the 

 current sufficiently to allow the fish tn ascend without difficulty. 



The foot of the ladder shall be placed where there is most running water, 

 and with the best lead for the fish to approach it ; and if the ladder should 

 project beyond the toe of the dam, there shall be an apron of stone formed 

 to the dam, extending as far down the river as the entrance to the pass or 

 ladder, and extending throughout the whole length of the dam at either 

 side of the ladder, and on a high enough level to prevent there being any 

 pool in the river, or sufficient depth of water farther up than the entrance 

 to the said pass or ladder, by which the fish might be induced to remain 

 there obstructed in their ascent, and not be led to the ladder. 



Note. — The Commissioners would recommend the following details to be 

 adopted in the construction of salmon ladders, in addition to those 

 given in the foregoing bye -law, but do not insist on them, provided 

 some other perfectly efficient arrangement be substituted — viz., the 

 side walls to be not less than twenty-two inches in height ; the breaks 

 to be not less than eighteen inches in height, with openings of ten 



