The River Allan

ALLAN WATER ANGLING IMPROVEMENT ASSOCIATION.

General description.

The Allan Water, whose underlying geology throughout its length is Devonian old red sandstone, rises high on the northern slopes of Wether Hill and after falling to the valley floor it flows through the low lying haughs from Blackford downstream to Ashfield. The river has been heavily engineered firstly in the 1860’s to accommodate the railway line and again in the 1940’s to improve agricultural output. From Blackford it flows through a mixture of rough marshland and arable land in a westerly direction for some eight kilometres to Greenloaning where it is met by the Keir and Millstone Burns, and the River Knaik which is a major spawning tributary. From this point downstream the river assumes much larger proportions and firstly flows south-westerly then in a southerly direction, joined by numerous tributaries, until it reaches Ashfield. Land usage in this section is a mixture of improved grazing, arable, and intensively planted Christmas trees. The river flows through substrates which comprise sand, gravels, and brown forest soils, over this whole section and is prone to erosion when river bank vegetation is disturbed. This is ideal dry fly water and when conditions allow ideal salmon and sea trout water. The Association only controls about half of this upper section but there is plenty of room for everybody.

Downstream of Ashfield the river assumes a totally different character flowing as it does over old red sandstone outcrops which form pools and glides which are ideal as salmon holding pools and the river between Ashfield and Dunblane is much fished. The river continues to tumble over rocky outcrops until it reaches the valley floor at Bridge of Allan where substrates again become predominantly cobbles and gravels until the tidal section is reached. The tidal section is fairly heavily affected by old dead trees which have been washed down the river and trapped in the mud. Hogweed is prevalent almost everywhere on the river.

Historical.

Historically the river has been much used, and abused by man and with the coming of the railway north in the 1880’s the river was much diverted, as it remains today, and industries began to spring up to make use of the river and improved transport links to our ports and cities. During this industrial revolution, paper and woollen mills sprang up along the river’s banks and at one time there were 12 mills on the Allan Water between Bridge of Allan and Kinbuck including paper mills, meal mills, dye works, and woollen mills, diverting the water for industrial use and often pumping it back loaded with chemicals and other toxic waste. There were also numerous other dams on the smaller tributaries such as the Millstone, Glassingallbeg, and Keir Burns for local meal mills. The dams provided ideal vantage points for poachers, who would haunt the sluices with gaffs, jiggers, and nets. Most of these mills have now gone and the dams have fallen into disrepair. Two however remain in operation, one at Bridge of Allan where water is diverted for cooling purposes in plastic closure production, the other at Ashfield where a significant weir exists and water is diverted for power generation. The effects of these on the river have not yet been quantified.

In 1942 the river was much altered above Kinbuck under the terms of the 1941 Land Drainage (Scotland) Act as a means of increasing the area available for producing food. The water table was lowered by several feet by blowing up the rock shelves at Kinbuck Bridge, a task carried out by Polish prisoners of war. At the same time almost the whole of the river between Blackford and Kinbuck was dredged and wood piles put in place to keep the river from moving. This scheme has been subject of much repair work since then and successive works carried out under the Act have seriously degraded the habitat between Blackford and Kinbuck as engineers sought to straighten the river channel to improve run off. This has resulted in the loss of large areas of gravel in the main river which used to be valuable spawning gravels. Fortunately the Act is now repealed and hopefully the river can in time settle down again..

General Statistics

         Catchment Area                                                          61Km2                          Total watercourse length.                      >140Km
         Number of Tributaries                                                31                          Number of still waters > 0.5Ha.             19
         Number of obstructions (Man Made)                        17                          Other obstructions                                  8                                                         Length barred to migrating fish                                >50Km.                    Maximum altitude.                                280m OD
         Average rainfall                                                          1384mm.                 Mean Flow                                          5.19m3s-