Experience with GWDTE’s in Scotland Johan Schutten Principal Ecologist Scottish Environment Protection Agency Johan.schutten @sepa.org.uk

Our experience Johannes questions: Progress in RBMP2 since RBMP1 Existing guidelines and technical reports helpful; YES More specifically: Identification of GWDTE Assessment of pressures (Chemical and quantity pressures Identified impacts Assessment criteria: contributions from groundwater Either pollutant load and TV’s (chemical) of changes in the hydrological regime (quantity) Current approach in comparison the RBmP1 Existing guidance docs and technical reports: helpful@ sufficient? Existing gaps

Identification and impact assessment In licensing /planning advice case work Risk based assessment of potential impacts 2 survey levels: high-level to assess potential risk SNIFFER categories of Wetlands (wider then GWDTE) : but with link to groundwater dependency: 1st level risk screen Detail to assess GW dependency (ecology + Hydrology and hydro-geology..) Guidance of SEPA website (last slide for links) Steer towards avoidance rather than damage Identify mitigation (maintain most of GW flow to GWDTE to ensure sustainable functioning of GWDTE; link to ‘significant damage) Link to Biodiversity importance – size of acceptable damage

Case work Identification .. Map of how survey info is needed Result: windfarms; hydropower, developments: avoid GWDTE impact.. Work with Industry: Industry construction guidance (link last slide)

In RBMP 2 status assessment Process (UKTAG): focus on Natura 2000 + increasing risk -> increasing detail of assessment Stage 1: Risk screening Use Nature Conservation quality assessment as first step Stage 2: Desk assessment of medium and high risk sites Quantitative Assessment (groundwater level) source-pathway-receptor model a) the ‘source’ or presence of level pressures/ abstractions (score 0 to 3 depending on abstraction as a % of recharge), b) the ‘pathway’ or degree of hydrological connectivity between ‘source’ and wetland (score 0 to 3), c) the ecological dependence of the ‘receptor’ (the GWDTE) on groundwater (score 0 to 3). Qualitative Assessment (chemistry) Nitrate threshold values were assigned to each of the habitat types present using the UKTAG nitrate threshold guidance (2012 Site walk over surveys (+ protocol) Local surface pressures: agricultural land management / manure heaps…. -> local solutions! Code SNH Condition Status* Current Risk? 1 Favourable Improving Negligible 2 Favourable Maintained 3 Favourable Declining Medium 4 Unfavourable improving 5 Unfavourable Maintained Low 6 Unfavourable Declining High

RBMP2 (2) Stage 3: Review phase Review ‘at risk sites from stage 2’. Review pressure: local desk top review: one pressure acting or more pressures (use licensing database etc.) Review ecological condition and likely cause of impact (contact with Nature conservation colleagues (SNH) If needed detailed desk based hydrogeological assessment of pathway 20 wetlands (from 195 designated sites) were flagged up as a concern through risk screen: none of these were deemed to be downgraded due to groundwater issues. All due to surface water management (either drainage or sediment inputs though artificial surface pathways) or overgrazing damaging conservation feature. No GWB at poor status due to GWDTE in RBMP2

GWDTE water quality and Quantity TV’s Groundwater Water Quality Threshold Values: 2012 (UK agreed, presented to WG GW in Brussels; link to report on last slide) UK wide correlation of Nature Conservation site ecological condition and nitrate concentrations in the groundwater that feeds the sites. 300+ sites + statistical and rule based (expert) analysis, resulting in the Nitrate TV’s

Scottish new monitored evidence (2010- 2014) Extensive SEPA monitoring between 2009 and 2015 (EnviroCentre) 54 hourly loggers at 9 sites across Scotland Groundwater level Surface water level 10 raingauges (existing network) Extensive soil and water sampling by SNH between 2010 and 2013 (EnviroCentre) Analysed in 2014/2015 by Envirocentre; results draft

Example: Springs, Flushes and Seepages (Typology 3)

Tufa-forming spring conceptual model Seepage/flush conceptual model

Summer and winter water table-duration curves spring, flush and seepage. Median curves based on data from 5 monitoring locations across 4 sites Aspect Scottish observations Guideline Source/justification Summer: typical water level range 95%-ile to 5%-ile, median of all locations: -0.14 m to +0.03 m Most of the time between -0.2 and 0 m. Based on monitoring data at five Scottish spring, flush and seepage locations. Winter: typical water level range -0.01 m to 0.06 m Most of the time between 0 and +0.1 m. High water levels Highest record: +1.1 m Typically up to +0.2 m, depending on supply mechanism. Median of highest records of all locations: +0.2 m Low water levels Lowest record: -0.4 m Typically not lower than -0.2 m, depending on supply mechanism. Median of lowest records of all locations: -0.2 m Flows No data available Suitable water flows in springs, seepages and flushes are essential to maintain these wetlands. No data available for Scotland. Nitrate Groundwater: third quartile of all samples: 0.25 mg/l N-NO3 or 1.1 mg/l NO3. Groundwater weeding wetland: 9 mg/l NO3 Vast majority of sample values at or below detection limit of 0.5 mg/l N-NO3. Thresholds are based on UKTAG (2012) values for spring/seepage. Surface water: third quartile of all samples: 1.3 mg/l N-NO3 or 5.8 mg/l NO3. Phosphate 0.10 mg/l P-PO4 No conclusive evidence. Approximately 50% of sample values at or below detection limit of 0.2 mg/l PO4. No threshold value set by UKTAG (2012). 0.010 mg/l P-PO4 Summary of hydrological and hydro-chemical variables that maintain spring, flush and seepage in good condition

Example from Scotland: Machair Eoropie Machair 2003, North Lewis, Western Isles. Photo by T Dargie

Machair guidelines (draft)

Another example: Swamp Short-term water table fluctuations winter 2011 (left) and spring 2012 (right).

Swamp guidelines (draft)

So.. Good progress.. Lot of stakeholder education! Identification of GWDTE Assessment of pressures (Chemical and quantity pressures Identified impacts Assessment criteria: contributions from groundwater Either pollutant load and TV’s (chemical) of changes in the hydrological regime (quantity) Current approach in comparison the RBmP1 Existing guidance docs and technical reports: helpful@ sufficient? YES: but need alignment across EU of GWDTE TV development / categories Existing gaps What is significant damage.. 1 % of surface.. 10 %... Need get experience and alignment across EU References: http://www.sepa.org.uk/media/144266/lups-gu31-guidance-on-assessing-the-impacts-of-development-proposals-on-groundwater-abstractions-and-groundwater-dependent-terrestrial-ecosystems.pdf http://www.sniffer.org.uk/knowledge-hubs/resilient-catchments/water-framework-directive-and-uktag-co-ordination/a-functional-wetland-typology-for-scotland/ http://www.wfduk.org/sites/default/files/Media/Environmental%20standards/GWDTE%20chemical%20values_Final_230312.pdf http://www.snh.org.uk/pdfs/strategy/renewables/Good%20practice%20during%20windfarm%20construction.pdf