oj the Fishery Board for Scotland. 



247 



APPENDIX N. 

 SALMON FISHERIES. 



MR. CALDERWOOD'S REPORT. 



Fishery Board for Scotland, 

 March 1914. 



I have the honour to report upon my inspections, etc., in 1913. 

 Forth District. 



From time to time during the summer I received information of the 

 serious condition of the Forth below StirHng. The pollutions of this, 

 the tidal section of the river, are now very great. The town of Stirling 

 discharges its drainage directly into the river by six outfalls, and no 

 attempt of any kind is made to purify the effluent. This of itself is 

 sufficient to cause gross pollution. The population of Stirlingshire was 

 160,991 in the census of 1911. 



Below Stirling, the Bannock Burn forms, in its lower part, another 

 convenient drain for the discharges of various coal pits, and, similarly, 

 the Raploch Burn, which joins the river on the south side just above Alloa 

 Bridge, comes out perfectly black with coal washings from Cowie and 

 Plean. Coal washings are, I understand, specially difficult to filter, as 

 has already been shown at Plean. Mixed with the coal washings, how- 

 ever, is all the domestic sewage of these populous mining villages. On 

 the north bank the waters of the Devon enter, and these are polluted to 

 an extent which almost defies description. When the tide is out the 

 black mud, impregnated with putrid matter, gives off an odour sufficient 

 to produce acute nausea to one walking along the bank to which the wind 

 blows. I have seen some very foul river beds, but I think I have never 

 seen any stream reduced to a more revolting condition. At Cambus 

 there is a weir giving water to the local distillery, and close to this, at the 

 time of my visit, a pipe was discharging an orange-coloured fluid, which 

 I took to be pot ale. The rapid putrifaction of this complex bi-product 

 is, I expect, largely responsible for the overpowering odour which is given 

 off by the mud below. The tide flows up to this weir, and it is no doubt due 

 to this fact that sea trout and a few salmon are enabled to ascend to the 

 less-polluted river above. Like domestic sewage, pot ale is capable of 

 purification by bacterial methods, the toxic properties of pot ale being 

 fifteen times as great as that of the complex sewage of the city of Man- 

 chester. 



With an inflowing tide in the Forth, the pollutions of the Devon are 

 carried up the river, just as the pollutions of Stirling are also carried up. 

 With the ebbing tide the accumulation of all sorts of objectionable matter 

 comes down the river, and, especially when the natural flow of the river 

 is small, as in the past dry summer, much of the matter is deposited as 

 foetid sludge on the banks and river bed. When, with a small river strong 



