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

2. 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: sufficient?
Existing gaps

3. 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

4. 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)

5. In RBMP 2 status assessment
Process (UKTAG): focus on Natura 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

6. 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

7. 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 sites + statistical and rule based (expert) analysis, resulting in the Nitrate TV’s

8. 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

9. Example: Springs, Flushes and Seepages (Typology 3)

10. Tufa-forming spring conceptual model
Seepage/flush conceptual model

11. 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

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

13. Machair guidelines (draft)

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

15. Swamp guidelines (draft)

16. 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: 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: