River Carron Description & River Photos – A Short Report Eur Ing ...

Grangemouth 100MW Biomass Plant River Carron Fisheries Management Group 

Electricity Act 1989 Section 36 Consent Inquiry Water Pollution & Fishery Issues 

River Carron Description & River Photos – A Short Report 

Eur Ing Tony Harris CEng CSci BEng(Hons) MIChemE MIFM 

River Carron Fisheries Management Group (R.C.F.M.G) 

May 2012 

1



Frontispiece: 

Atlantic Salmon migrating upstream in the River Carron by leaping over Larbert Weir. 

Photograph ©John Girvan. 

1.0 Introduction 

1.1. This short report provides photographs of the River Carron at various locations along its length 

to give the reader a perspective on the current size and current water flow rates in the River 

Carron, for comparison to the proposed Forth Energy Grangemouth Biomass Plant Blowdown 

Effluent flow rate of 0.93 m/second. 

1.2. The River Carron is a small spate river located in Central Scotland. The photographs and 

information included in this report reflect this. Each photograph is individually numbered with 

locations indicated on the OS Map in Section 5. 

1.3. A river catchment map is also included and shows the layout and the number of the reservoir in 

the upper catchment. These current reservoir impoundments and abstractions have a 

significant negative impact on the River Carron water flows. Currently, up to 75% of the total 

annual rainfall in the upper catchment is abstracted out of the system, with only 25% flow 

supplied for the rivers environment. The allowable abstraction rates and supplied minimum 

compensation flows are detailed in the SEPA CAR Licence No. CAR/L/1014292 for Carron Valley 

Water Treatment Works. 

1.4. The low river flows impose significant risk in terms of lack of dilution when polluting effluents 

enter the river channel. 

2



2.0 River Carron Description 

2.1. The River Carron rises in the uplands of Carron Valley in the Campsie Fells. The river flows for a 

short distance before being impounded by Carron Valley Reservoir which was built 1935 – 1938. 

The River Carron then re-emerges as a small reservoir compensation flow from the eastern 

slipway of Carron Valley Reservoir Dam at a rate of 9.1 Ml/day (= 0.1 m3/second) and flows in 

an easterly direction, for approximately 20 miles, through Carron Valley, Carron Glen, and the 

settlements of Denny and Larbert and Falkirk before entering the upper Firth of Forth at 

Grangemouth. The catchment has a total stream network length of about 75 miles. 

2.2. The River Carron drains an area of approximately 192 km2 before entering the Firth of Forth via 

the Carron Estuary at Grangemouth. The Carron catchment supports a mix of urban and rural 

land-use. Commercial conifer forests cover the upper reaches around the Carron Valley 

Reservoir while agriculture is the main land use along the middle reaches. Both the Carron 

Valley and Loch Coulter reservoirs are significant water resources serving important functions in 

the supply of drinking water. In the lower reaches the land becomes more heavily urbanised 

with major road networks, towns and settlements which includes parts of Cumbernauld and 

Falkirk together with Denny, Bonnybridge and Larbert. 

2.3. The headwaters of the Carron are effectively compensation waters from a series of reservoirs 

which have been built on the system to harness water for the population of much of the 

eastern central belt of Scotland. There are 8 reservoirs in the catchment that affect runoff 

(namely Carron Valley Reservoir, Loch Coulter Reservoir, Earls Burn 1 Reservoir, Earls Burn 2 

Reservoir, Buckie Burn Reservoir, Faughlin Reservoir, Little Denny Reservoir and Drumbowie 

Reservoir). The largest of these is Carron Valley Reservoir. 

2.4. The SEPA CAR Licence No. CAR/L/1014292 (CARRON VALLEY WATER TREATMENT WORKS) 

states that Scottish Water have to maintain a minimum river flow of 41.8 million litres/day (0.48 

m3/second) at the Scottish Water Langhill River Gauging Weir, Carron Glen, located at OS grid 

reference NS 773 844. This flow requirement provides a minimum low flow to protect the 

rivers environment. 

The SEPA CAR licence states the maximum daily abstraction rate for Carron Valley WTW and 

Gartcarron WTW is 152.5 million litres/day (=1.76 m3/second) from the catchment. The licence 

also states the minimum flow in the river at Langhill Weir should be 41.8 million litres/day 

(=0.48 m3/second), this indicates that only one quarter of the catchments water is allowed into 

the river when reservoirs are below their full level (when no dams are over-topping). 

This is a significant problem for the river system as the reservoirs rarely overflow due to the 

high demand for potable water in the district. Carron Valley Reservoir was originally 

constructed 1935 – 1938 to provide water for Grangemouth Industry and the population of 

Falkirk Council which is now approximately 145,000 people, who use on average 160 litres of 

water per day. Grangemouth Industry is a very large consumer of water. 

The catchment runoff is increased to some degree by Sewage Plant treated effluent returns 

from the 4 Sewage Treatment Plants in the system (namely Denny Sewage Works – Denny, 

Bonnybridge Sewage Works - Roughmute, Dunswood Sewage Works - Cumbernauld and 

Dalderse Sewage Works - Falkirk. 

3



2.5. Typical low summer flow in the River Carron (with 41.8 million litres/day (0.48 m3/second) at 

the Scottish Water Langhill River Gauging Weir) corresponds to a river level of 0.2m measured 

at the SEPA Headswood Gauging Station Weir. 

2.6. The River Carron is classified under the European Commission’s Water Framework Directive 

(WFD). The EC Water Framework Directive, which came into force on 22 December 2000, 

establishes a new, integrated approach to the protection, improvement and sustainable use of 

Europe’s rivers, lochs, estuaries, coastal waters and groundwater. Scottish Ministers have 

committed to implementing the Water Framework Directive. 

2.7. The River Carron catchment contains 14 baseline surface water bodies (a baseline waterbody 

has a catchment area greater than 10km2) including five heavily modified water bodies and 

three artificial water bodies (canals). This is stated in the SEPA River Basin Management Plan 

River Carron Profile 2009 (Ref: GCCIPC Inquiry Fisheries Documents – Volume 1 – Doc 20). 

River Carron catchment water bodies were classified by SEPA in 2009 as having either Poor, 

Moderate or Good Ecological Status. The classification scoring for each waterbody is made up 

of over 20 factors including the Fish Species and Fish Populations present. All classification 

scoring factors are listed in the SEPA 2009 Classification Spreadsheet which is available on the 

SEPA website. It contains the classification scores for all the River Carron catchments 

waterbodies. www.sepa.org.uk/water/river_basin_planning/area_advisory_groups/forth.aspx 

2.8. Under the EC Water Framework Directive all classified waterbodies within the River Carron 

Catchment must achieve “Good Ecological Status” by at least 2027. This is stated in the SEPA 

River Basin Management Plan River Carron Profile 2009. (Ref: GCCIPC Inquiry Fisheries 

Documents – Volume 1 – Doc 20). 

2.9. Any industrial development which could derogate this River Basin Management Plan objective 

is unacceptable and contravenes the WFD objectives as stated in SEPA document - The Future 

for Scotland’s Waters, Guiding Principles on the Technical Requirements of the Water 

Framework Directive, May 2002. (Ref: GCCIPC Inquiry Fisheries Documents – Volume 1 – Doc 

19). 

2.10. The proposed Forth Energy Grangemouth Biomass Plant will significantly affect populations 

of migratory fish in the River Carron including River Lamprey, Atlantic Salmon and Sea Trout, all 

of which are confirmed species as stated in the Falkirk Area Biodiversity Action Plan 2011 – 

2014 (FABAP) (Ref: GCCIPC Inquiry Fisheries Documents – Volume 1 – Doc 30). 

2.11. River Lamprey is a European Protected Fish Species and receives conservation status under 

Annexes II and V of the EU Habitats Directive Appendix III of the Bern Convention and is on the 

UKBAP Priority List (GCCIPC Inquiry Fisheries Documents – Volume 1 – Docs 31 & 47). 

The reduction in upstream adult and downstream juvenile fish migration survivability as a direct 

result of the biomass plant blowdown effluent discharge will negatively impact River Carron fish 

populations and this could cause a derogation in WFD classification, and will contravene the 

WFD objective of achieving “good ecological status” for many of the River Carron catchments 

water bodies. This environmental impact is unacceptable. 

4



3.0 Catchment Map indicating Abstractions and Compensation Flows 

5



4.0 OS Map indicating River Carron Photograph Locations 

6



5.0 River Carron Photographs 

Photograph 1: Carron Valley Reservoir Slipway (re-emergence of the River Carron) 

Photograph 2: Carron Valley Reservoir typical water level – rarely overtops into river. 

7



Photograph 3: Carron Valley Reservoir Slipway typical water flow (0.1 m3/second). 

Photograph 4: River Carron @ Carron Valley 500m downstream of dam 

8



Photograph 5: River Carron Summer Flow (0.48 m3/second) at Langhill Weir River Gauging Station 

Photograph 6: River Carron (25/5/12) at Dales Bridge, Denny 

9



Photograph 7: River Carron Typical Summer River Level of 0.2m (25/5/12) at SEPA Headswood 

River Level Gauging Station 

Photograph 8: River Carron Typical Summer Flow entering the tidal River Carron Estuary (25/5/12) 

at Carron Works Weir, Falkirk 

10



Photograph 9: River Carron Tidal Estuary indicating Dalderse Sewage Treatment Works effluent 

discharge (25/5/12) plugging entire width of river channel 

Photograph 10: River Carron Typical Summer Freshwater Flow at Low Tide - Kerse Bridge, 

Grangemouth (25/5/12). The proposed biomass plant blowdown effluent discharge pipe location 

(Option 1) is 2.4km downstream from this bridge. 

11



Photograph 11: River Carron Tidal Channel at Option 1 location for proposed biomass blowdown 

effluent discharge pipe location. Option 1 is 2.25km upstream of the Firth of Forth. Photo shows 

higher level mudflats to the left and the lower River Carron Channel to the right separated by a 

man-made Tailbank (breakwater on OS map), 

12



Photograph 12: River Carron Tidal Channel at the Option 1 Effluent Discharge Location (on South 

bank adjacent to red navigation buoy). Note the size of the raised South bank which is exposed at 

all low tides . The applicant has stated the pipe will not be located in the centre of the channel to 

mitigate boat navigation issues. Locating the pipe as proposed along the south bank will not 

promote rapid mixing and dilution because there is no water at low tide on this exposed bank. 

13

River Carron Description & River Photos – A Short Report Eur Ing ...

Create successful ePaper yourself

Delete template?

Save as template?