Linlithgow Angling Club is an active member of the River Forth Federation which is working to improve the fish and other aquatic life of the River Avon. We believe the operation of a biomass powered station at the Grangemouth site would compromise the health of migratory fish and lead to reducing stocks of these fish. We therefore object to the Forth Energy proposal.
At no time is the negative effect on the ecology of the River Avon discussed in the scoping document. The contention that the development would result in, “..no significant impacts on aquatic life” would seem to be ill-founded given the lack of consideration for any river system adjacent to and east of the proposed site.
The Physics The proposal that the discharge, “…will be at maximum of ( sic ) 12 o
C above the ambient temperature of the receiving water..” and will be released into the fresh water of the River Carron can only result in a layer which is less dense than the estuarine water given its higher temperature and lower salinity. This surface layer would be relatively stable. The effect of this is that its heat could not be dissipated by sinking into the deeper channels or by mixing with the lower water strata. This mass of warmer water would be carried towards the bay into which the River Avon discharges by the eastward movement of the ebb tide. Flood tides are stronger on the north side and ebb tides on the southern side of the estuary as the tidal bulge moves clockwise along the Scottish coast.. ( Scottish Executive Development Department,
Kennet Pans Coastal Realignment, Feasibility Study ). Indeed published data from
SEPA show that the O2 levels in the Forth estuary are at a minimum in the summer months as might be expected, because of less inflow of O2 enriched water, the flow tide over warm mud depressing the O2 levels etc. In addition the Environmental
Quality Standard (EQS) for oxygen levels has been breached by as much as 14 days between June and September. Any additional burden would be unacceptable especially since these depressed levels coincide with migratory fish movement.
The relative positions of the proposed plant and the channel of the Avon through the mudflats are shown in the following photograph
P ROPOSED SITE M
OUTH OF THE
C
ARRON
C
HANNEL OF THE
R
IVER
A
VON

A REAS OF
DEPOSITION
Several factors exacerbate this situation. In summer, the higher air temperatures and increased radiation warming of the surface water will increase the stability of the layer. In addition, reduced summer flow in the River Carron would result in a reduction of thermal dilution.
A second major factor is the relatively shallow water found in the bay at the mouth of the River Avon. This is well illustrated in the photograph where the mudflats are covered with only a shallow depth of water producing the mirror effect. This reduction in water depth found in this area would mean that a significant proportion of the water column would be made up of the warmer water.
The tidal regime found in the upper Forth estuary is an additional problem which would concentrate the warmer water, associated with the discharge of cooling water from the proposed plant, in the area of the mouth of the River Avon. The region of the estuary between Rosyth and Alloa has a local anomaly known as “lackie” tides.
These are double tides which occur around the time of slack water. The overall effect of these tides is to produce a prolonged period of weak currents around the time of slack water when the tide is turning.( Elliott and Clark 1998 ) The outcome of this phenomenon is observed every low tide. The presence of large areas of mud in the upper estuary notably between the Kincardine Bridge and Kinneil on the south side is witness to this sluggish movement of water which allows suspended solids to drop out of suspension to form the deep deposits of sediments.
These areas of deposition are clearly shown on the following chart.
G ENERALISED
TIDAL FLOW
D. McLusky 1987

If these points are summarized, the following sequence of events will be seen to occur.
1 Warm water, up to 12 o
C above the surrounding water, is discharged into the River
Carron.
(See also response from the Carron’s RCFMG at http://rcfmg.co.uk/reply.pdf)
2 This warmer water is carried by tidal flow eastwards along the south shore of the estuary, its temperature and low salinity preventing it from mixing and diluting.
3 Local tidal features cause this warmer water to accumulate in the bay at the mouth of the River Avon. The shallow nature of the bay means that the water will retain its warmth or become warmer during periods of low dilution flow from the Carron coinciding with summer weather.
It should be noted that what is true for the fate of the cooling water is also true for all other contaminants which would be released by the proposed plant, that is, they would accumulate in the area of the Avon mouth.
The Biology As the temperature of water increases, its ability to hold oxygen decreases. This is seen in every kitchen when bubbles are released from water which is being heated up long before it nears boiling point. The significance of this simple fact is that any organism in the area under consideration would find itself in a changed habitat where oxygen is less plentiful that before. This problem is compounded by the fact that the chemical reactions inside so-called “cold blooded” organisms, their metabolism, increases as their body temperature increases. They are thus caught in a situation where their metabolism is increasing, meaning that they will need more oxygen but at the same time that very gas is becoming scarcer in the water. This places increased stress on the organism. In the case of fish, it also increases their susceptibility to disease for a rather subtle reason. In order to get more oxygen when there is less in the water, they have to increase the flow of water over their gills in much the same way that a human has to breath faster when at altitudes where oxygen levels are lower. The increased flow rate of water over their gills gives increased exposure to levels of potential toxins and disease causing organisms, pathogens, in the water. Furthermore, the higher water temperature allows pathogens to grow more rapidly. The combination of reduced oxygen and increased pathogen growth increases the chances of fish disease.
Warmer water also encourages the growth of other micro organisms which, although not directly harmful to fish, take up oxygen from the water, especially where there is an abundance of organic material, for example sewage, which can provide a food source for them. Where these micro organisms occur in abundance, the oxygen levels can be drastically reduced.
Although lampreys and eels, (both protected species), enter the River Avon the two most important migratory fish from the angler’s perspective are the Atlantic salmon and the sea trout. When Linlithgow Angling Club first obtained leases for the River
Avon, there were no salmon or sea trout running the river as a consequence of over a century of pollution, mainly from paper mills.

Through the work done by members of Linlithgow Angling Club and other clubs in the River Avon Federation, salmon are once again seen in modest numbers in the system. Sea trout too are making a reappearance. Both of these fish breed in the river and migrate to the sea where they feed and mature. They belong to a group of fish known as salmonids which are very sensitive to the level of oxygen in the water and hence to the water temperature. Any factor which contributes to a reduction in oxygen levels can only increase the biological stress experienced by these fish. While there are indeed salmon and sea trout in the River Avon system, their numbers are small and their future is by no means guaranteed. In the case of sea trout for example, in the years from 1999 to 2009, while the number recorded by members showed an overall increase from 10 in 1999 to 29 in 2009 but 2008 saw a drop to only 16.
Sea trout are particularly at risk from thermal oxygen depletion as they tend to spend more time near the river mouth whereas salmon migrate to the open sea to feed. Both groups will congregate around the river mouth waiting for suitable conditions in which to make their way back upriver. These conditions involve suitably high river levels. The final difficulty these fish have is that the conditions which are unsuitable for migrating upriver, i.e. low water in the river, are the very ones which would see the greatest effect of the discharge from the proposed power plant. The outcome of this would be that the greatest numbers of fish would be concentrated in the very worst area as far as disease and oxygen levels are concerned.
Any additional factors e.g. thermal pollution which could tip the balance regarding the continued presence of these fish in the River Avon would be extremely unwelcomed.
It is believed that smolts, i.e. young salmon and sea trout migrating from the river to the sea, are especially sensitive to fluctuations in water temperature.
(http://www.atlanticsalmontrust.org/knowledge/salmon-factshtml)
It is of little consequence that thermal stress brought on by discharge from the proposed power plant would in all probability not produce massive fish kills at the mouth of the River Avon. It is more likely that the effect would be more gradual. The constant exposure of fish to sublethal stresses does not produce spectacular fish kill events which would certainly and justifiably produce a national demand for action.
Fish becoming extinct in a river system over ten years are, however, just as extinct as those killed in a single incident.
Summary For all of the reasons outlined above, Edward Law ( Aquatic Pollution, pub John Wiley&Sons ) maintains that,
“For reasons of convenience and economics, power plants are often located on estuaries. Such sitings are made because large population centres are frequently found adjacent to estuaries and because the estuary obviously provides a source of cooling water for the power plant. From the standpoint of water pollution, however, estuaries are just about the last place where one would want to locate a power plant.”

Conclusion
Linlithgow Angling Club objects to the siting proposals for the following reasons:
1) At no point in the scoping document is any reference made to the effects that the proposed development at this site would have on the biology of the River Avon and in particular the effects on migratory fish movements.
2) Such development would have a negative effect on migratory fish movement both in the River Carron and the River Avon and would adversely affect attempts to re establish these species in their historical habitats.