Contract on behalf of Marine Harvest

Assessment of the capacity of Shiel to accommodate additional inputs of phosphorus without comprising the current WFD/ RAG status

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The purpose of this report is to provide an evaluation of the capacity of Loch Shiel to accommodate increased contributions of phosphorus without adversely affecting the current WFD ( Water Framework Directive) and Red Amber Green ( RAG) water quality status. This has been done using the PLUS+ model in its standard configuration as used by SEPA. This model uses the LCS88 land cover and 2001 population census data as input parameters.

PLUS+ model

The James Hutton Institute' s predecessor, the Macaulay Land Use Research Institute, developed the Phosphorus Land Use and Slope ( PLUS) model in the 1990' s in association with the Forth River Purification Board ( formerly a regional office of SEPA); with financial support from Scottish Natural Heritage. The PLUS model was developed to determine the relationship between anthropogenic drivers of nutrient enrichment ( especially Phosphorus [ P]) and trophic status of standing waters in . The model was applied to 170 lochs and proved to be a robust tool.

SEPA were very interested in using PLUS to undertake further assessment of loch phosphorus concentrations/ loads in response to changes in land cover and point sources of P. However, the PLUS model was based on old GIS technology, lacked any kind of user friendly interface, and had no facilities for maintaining records of simulations in a central database. In collaboration with SEPA, significant progress

Aberdeen has been made towards addressing these issues and following 8 years of Craigiebuckler development, refinement and testing, PLUS+ is now recognised as a credible Aberdeen AB15 8QH Scotland UK management tool for assessing new fish farm licence applications. The most Dundee Invergowrie Dundee DD2 5DA Scotland UK

Tel: + 44 ( 0) 844 928 5428 Fax:+ 44 ( 0) 844 928 5429 info@hutton. ac. uk www. hutton. ac. uk James recent development with PLUS+ has been to update the land cover data used to derive the phosphorus loads, however since these new data are not currently part Hutton of the PLUS+ configuration used by SEPA the landcover from the LCS88 were Limited adopted in this study. Impactthrough PLUS+ works by summing the various sources of P in the model to calculate Science phosphorus concentration ( TP — Total Phosphorus in micrograms per litre —ug/ 1) and calculated phosphorus loads (J in kg). SEPA provides measurements of P in µg/ I and PLUS+ calculated the equivalent load in kg. Where the load is known the concentration can be calculated and vice versa using the area and mean depth of the loch. A comprehensive description of the model, data sources and calculation methods can be found in the user manual which can be downloaded here.

Loch Shiel catchment

Loch Shiel is a 28 km long freshwater loch, with a mean depth of 41 m. The catchment is situated 20 km west of Fort William in , Highlands. The total catchment area is 250 km2 and comprises 11 sub -catchments. Loch Shiel is designated under the Directive ( 78/ 659/ EEC on the quality of fresh waters requiring protection or improvement in order to support fish life). The catchment consists of mountainous, largely uninhabited terrain with some forestry at lower altitudes around the Hurich, Callop and Finnan rivers. The large freshwater loch 19. 9 km2) is a good example of an oligotrophic loch ( low nutrient status) and therefore designated as a Site of Special Scientific Interest. Loch Shiel is also a Special Protection Area, designated as a rare breeding site for black -throated divers. Inputs of phosphorus to the loch from sewage effluent are minimal, reflecting generally low population densities in the catchment. The main concentrations of population are the villages of at the head of the loch and at the mouth of the loch. The only other known P inputs to the system are 5 freshwater cage fish farms along the length of Loch Shiel, which have been sited there since the 1980' s.

Background phosphorus concentrations

For this report, the observed water quality status of Loch Shiel was determined from two SEPA reported concentrations from 2009 and 2014. Whilst TP dames concentrations are generally low and characteristic of oligotrophic systems, there Hutton was a increase in the concentration observed in 2014 compared to 2009 ( 5. 95 µg/ I 6, 498 kg) and 3. 78 µg/ I ( 3, 743 kg) respectively). Without recent information on Limited fish farm consents/ development during this period, other possible changes within Impactthrough the catchment were investigated that might have increased the TP concentrations Science to the loch. Analysis of any spatial data should be performed with an awareness of the inherent uncertainties associated with data capture, extrapolation and interpretation. However, a comparison of the LCS88* and updated PLUS+ land cover** representing land use in 2015 show considerable change between 1988 and 2015. Notably, Table 1 shows an increase in the extent of course grassland from 1, 215 ha in 1988 to 8, 598 ha in 2015 possibly at the expense of heather moorland which has declined from 9, 773 ha to 4,099 ha respectively. The other significant land cover change is the area of montane habitat. This figure may represent some mapping error as montane/ moorland habitats are challenging to distinguish and validation is logistically difficult. Whilst the urban area in the catchment has expanded according to the recent spatial data ( 2015), population numbers have not been updated from the recent census. Effluent inputs may therefore be underestimated. According to this ' off- line' analysis, land cover change from 1988- 2015 has the potential to increase net P export by 127 kg. Given this relatively minor additional load to the loch it is likely that another source of P is responsible for the TP loads observed in 2014. These figures should be interpreted with caution. It is unlikely that the increase in TP concentration is associated with inputs from migratory geese as counts of the most common geese in this area, Greenland white -fronted geese, declined across the entire British wintering range in 2015 Fox et al., 2015). Over the past 20 years, the long term trend in the Loch Shiel catchment, indicates a slow gradual decline following larger numbers ( several hundreds) in 1970s, although numbers have stabilised within range 35- 50 since the early 1990s ( Francis et al., 2011). Marine Harvest were approached for supporting/ local information that could help explain this increase as the standard PLUS+ model uses the concentrations observed in 2014 to predict the capacity of the loch to accommodate further P inputs. James Table 1: Comparison of land cover and associated Total P loads derived from export coefficients from 1988 to 2015 Hutton Limited Standard PLUS+ ( LCS88)* Updated PLUS+ ( 2015)** Irnpactthrough Land Cover Area ( Ha) Area ( Ha) P ( kg) P ( kg) Science Blanket bog & peatland 862 19 737 16 Bracken 192 22 139 16

Broadleaved woodland 664 165 572 143

Cliffs 310 14 142 6

Coarse grassland 1215 139 8598 923

Coniferous plantation 1109 189 1289 215

Factories & urban 19 33 45 78

Heather all types 9773 1032 4099 428

Improved grassland 222 77 142 50

Mixed woodland 121 23 1057 197

Montane Montane vegetation vegetation 1364 7575 382 2222 OpenOpen canopycanopy youngyoung 1399 263 163 30 plantation plantation Recently ploughed land 43 33 Ripping 120 46 Smooth grassland 309 33 34 3 Woodland recently 8 6 0 0 felled

Road & rail 28 0

Water 2006 259 1985 268

Total P from land cover 2347 2474

LCS88: Land Cover of Scotland 1988 Updated PLUS+ ( 2015): Combined land cover from the LCS88 for semi natural upland areas, National Forest Inventory ( 2015) and broadly interpreted IACS ( Integrated Administration and Control System) data for managed/ agricultural systems and a number of other up to date sources of data.

Results

Results are displayed as a concentration in µg/ I followed by the phosphorus load either associated with it or derived from it in brackets. As previously explained all results are derived from the PLUS+ model with the standard configuration as used by SEPA. IIS dames The PLUS+ modelled P using its standard settings was 3. 62 µg/ I ( 3, 553 kg), equating to the " high" WFD class. Compared with the original SEPA 2009 Hutton measured concentration ( 3. 78 µg/ I ( 3, 743 kg)), this 5% discrepancy in the P Limited calculation was considered to be a good result (Table 2 and 3). Between 2009 and Impactthrough 2014 there was been a change in the status for Loch Shiel from High to Good Science Table 2), as P increased from 3. 78 ( 3, 743 kg) to 5. 95 ( 6498 kg), respectively. Table 2 Load derived Capacity to downgrade Measured Measured Measurements from measured to lower WFD standard status TP/ µg I TP kg TP kg SEPA 2009 High 3. 78 3, 743 2318 ( d/ g to Good) SEPA 2014 Good 5. 95 6, 498 3872 (d/ g to Moderate) d/ g = Downgrade The PLUS+ model is designed for evaluating scenarios. In this case, additional P loads were added to the model so that the simulated P was equal to the measured P reported by SEPA in 2014. This required the addition of 1, 914 kg described as being the amount of P discharged ( kg per annum) by Marine Harvest as part of their new fish farm proposal ( at this point the WFD status is " high" and as such there is no RAG status), plus an additional 1, 031 kg that would reduce the WFD status to " good". This 1, 031 kg can be considered as a shortfall in the current known loads of P entering Loch Shiel to meet the concentration observed by SEPA in 2014. To downgrade the status of Loch Shiel to a lower class would require a supplementary input of P of 3,872 kg before the status deteriorates to the Moderate" class. Note that these capacities are not cumulative — the total that can be added before the status is downgraded to " Moderate" is 3, 872 kg. RAG Status: The combined additional load to the loch ( Marine harvest 1, 914 kg + 1, 031 kg = 2, 945 kg) results in a downgrade of the modelled WFD status to " Good" and a " Green" RAG status. The additional P capacity of the loch, before RAG status changes to amber, is 2, 978 kg, and likewise an addition of 3, 734 kg P would be required before the RAG status changes to red ( Table 3). PLUS+ takes account of known sources of P from sub -catchments that drain into Loch Shiel, and it is possible that the currently unidentified source of P could be present. Given the size and depth of Loch Shiel, there is likely to be considerable variability in the P concentration along the loch and therefore a single measured/ modelled concentration may not be sufficient to represent this variability. It should also be noted that in the PLUS+ model, Loch Shiel flows to the coast so no downstream consequences of modifications to loads in freshwaters are foreseen. Table 3:

Capacity to Capacity t Modelled Modelled TP Modelled downgrade to RAG Lower Modelled downgrade status µg/ I load ( J) lower WFD status* downgrade TP to red standard

2009 Baseline High 3. 62 3553 2507. 5 N/ A - High 5. 6 N/ A N/ A 2009 Baseline plus 1, 914 kg P from MH High 5. 16 5467 593. 5 N/ A - High 5. 6 N/ A N/ A 2009 Baseline plus 1, 914 kg P from MH, plus 1, 031 to match SEPA

observation in 2014 Good 5. 95 6498. 2 3872. 5 Green 8. 7 3734. 8 2978. 8

Note that there is no RAG status for "High" quality POOR 11111 dames Breakpoints between WFD water status classes Hutton Outputs from the PLUS+ model are shown in the appendices to demonstrate the Limited breakpoints for the WFD classes and how these relate to the SEPA RAG status. In 2014, the breakpoint for the High/ Good class is 5. 6 µg/ I ( 6,061 kg) whilst the breakpoint for the Impact through Science Good/ Moderate class is greater at 8. 73 µg/ I ( 10, 371 kg). Although not relevant to the water quality status of Loch Shiel, this scheme continues into the lower water quality classes with break points at 17.45 µg/ I ( Moderate/ Poor), and 34. 90 µg/ I ( Bad/ Poor).

Disclaimer

The PLUS+ model uses mapped landcover and estimated P export coefficients that are subject to unknown levels of uncertainty, and whilst best efforts have been employed to produce a robust report, James Hutton Limited cannot be held responsible for any financial losses or other impacts incurred by Marine Harvest as a result of decisions made based on information contained in this report.

Appendices

A series of outputs with varying inputs, starting with the baseline LCS88 land cover model: Standard loads: James

PhJoslphms Land Ilse and 51ope - PLUS+ _ J Hutton Load fr. m master data CGdE' to loa 6om Catchment polygons SEPA montonng table GB Lakes Water Body D LUT SEPA classficatlon r LSP rt ano Limited 1. aCatdlmgtt a0d_ Net. ork . SHA_ 2014 tlkd Ludt y WBM o lap S A_ 2014_ Iod, da. . Load data I GBL About Impactthrough Analyse oat[ hment5 I Create and save scenario I Import uw created land rover polygons) I Create a report Additional resuhs Science

Graphical rel- ntabsn of calculated Total Phosphate mocentration and Break Paints. This graphc represents the ealmatad concentration as shown ar the' Analyse © tch* ients' tab

Calculated status of 21925, Lads Shi6. W810: 100208

ModeratefGood Goodhiigh

3. 62

6. 73 5. 52

G8 Lakes 0 ' Pery- I Lo. 4 & straam run- off s ear n mterata tD tden. Mean d tla m Lodz area mr

72278 36, 765, 639. 0 115, 093, 410. 1 1. 55 0. 82 4. 36 27, 000 22306 72, 879, 826. 2 77, 560, 685. 9 1. 55 0. 82 7. 16 30, 200

22223 4, 345, 347. 5 4, 345, 347.5 1, 55 0. 82 247 96, 000 21983 4,280, 659. 7 4, 280, 659. 7 1. 55 0. 82 4, 29 68, 500 22324 335, 512. 2 335, 512. 2 1. 55 0. 82 6. 53 23, 100 22291 499, 000. 1 499, 000. 1 1. 55 0. 82 4. 28 41, 000 21950 1, 311, 172. 8 1, 311, 1718 1, 55 0. 82 6115 41, 500 21846 499, 44L8 499, 441. 8 1. 55 0. 82 6, 13 14, 000 21937 774, 944. 7 774, 944. 7 1. 55 0. 82 4. 17 23,,300 22284 767, 085. 2 7'07, 085, 2 1. 55 0. 82 5. 29 17, 900

After the addition of 1, 914 kg P from Marine Harvest ( note that this is showing Amber - however the RAG classification doesn' t apply to " High" status):

Cal - hated status of 21925, LOO Shiel. WBM; 100208

ModeratejGood GoodMigh

8. 73 5. 62

22278 36,36, 765,765, 639.639. 00 115,115, 093,093, 410.410. 11 1.1. 5555 0. 82 4, 36. 27,27, 000000 22308 22308 72,72, 879,879, 826,826, 22 77, 560, 685. 9 1. 55 0. 82 7. 16 530,530, 200200 727. 23 4,345, 347. 5 4, 345, 347. 5 1. 55 0. 82 2.2. 4747 96,96, 000 000

21983 21983 4,4, 280,280, 659.659. 77 4,4, 240,240, 65917 65917 L55 0.0. 8282 4.4. 2929 68, 500

22324 22324 335,335, 512.512. 22 335,335, 512.512. 22 1.1. 5555 0. 62 6.6. 5353 23,23, 100100

22291 22291 499,499, 000.000. 11 499, 000. 1 1.1. 5555 0.0. 6262 4.4. 2828 41,41, 000000

21950 1,1, 311;311; 172.172. 88 1,1, 311;311; 172.172. 88 1.1. 5555 0.0. 8282 6. 15 41, 500

2184621846 999,999, 441.441. 88 499, 441. 8 1.1. 5555 0.0. 8282 6.6. 1313 14,14, 000000 21937 774,774, 944.944. 77 77+77+ 6944. 6944. 77 1.1. 5555 0. 87 4.4. 1717 23,23, 300300 2223122231 767,767, 085.085. 22 767, 085. 2 1. 55 0.0. 8282 5,5, 2929 17,17, 900 900 PON OM Na`N 11111 dames Following the addition of 1, 643 kg + 1, 302 kg P, PLUS+ modelled TP matches the measured TP - this can be considered to be the correct baseline against which Hutton capacity can be assessed: Limited

Impactthrough Science

Calculated stah. is of 21925, Loch Shiel. 4NBID: 100208

Moderate/ Good Good High

5. 95

8. 73 5. 62

22278. 36, 765, 639. 0 115, 093, 410. 1 1.55 0. 82 4. 35 27, 000 22308 72,879, 826. 2 77, 560, 685, 9 1. 55 0. 82 7. 16 530, 200 22223 4, 345, 347. 5 4,345, 347. 5 1. 55 0. 82 2. 47 96, 000 219834, 29D, 659. 7 4,280, 659. 7 1. 55 0. 82 4, 29 68, 500 22324 335,. 512. Z 335, 512. 2 1. 55 0. 82 6. 53 23, 100

22291 499, 000. 1 499, 000. 1 1. 55 0. 82 4. 28 41, 000

21950 1, 311, 172. 8 1,, 311, 172. 0 1. 55 0. 82 6. 15 41, 500 21846 499, 44L8 499, 441. 8 1. 55 0. 82 6. 13 141000 21937 774, 944. 7 774, 944. 7 1. 55 0. 82 4. 17 23, 300

22284 767, 085. 2 767, 085. 2 1. 55 0. 82 5. 29 17, 900

References

SEPA report ( Date unknown). Catchment pollution reduction programme under directive 78/ 659/ EEC on the quality of fresh waters needing protection or improvement in order to support fish life. Monitoring years 2002- 2005. Programme to achieve Guideline standards under Article 5 of the Directive http:// apps. sepa. org. uk/ fish/ pdf/ 12. pdf Fox, T., Francis, I., Norris, D & Walsh, A. 2015. Report of the 2014/ 2015 International census of Greenland white -fronted geese. National Parks and

Wildlife Service. Final report October 2015. http:// monitoring. wwt. org. uk/ wp- content/ uploads/ 2015/ 11/ Greenland- White- fronted- Goose- Studv- report- 2014-

15. pdf

Francis, I., Mitchell, C., Griffin, L. and Fox, A. 2011. Greenland White -fronted Geese. Land use and conservation at small wintering sites in Scotland. Final report, November 2011. http:// www. snh. gov. uk/ docs/ A678644. pdf