Ecological Indicators of Water Resource Pressure. Willie Duncan SEPA Jan 2013

Transcription

1 Ecological Indicators of Water Resource Pressure Willie Duncan SEPA Jan 2013

2 Outline Methods River Water Resources River Morphology Lakes Water Resources/Morphology Format Improvements over previous methods. Key Features of the method. Changes on the Impact Gradient Impact on classification

3 Improvements Over Previous Methods. RPB1 Lacked biological methods which describe hydro-morphological pressures. RBP1 Relied upon environmental standards. RBP2- Bringing use ecological indicators into the assessment process. RBP2 Improving pressure/response evidence base, and where possible develop biological metrics. Not big bang but an incremental improvement in capability.

4 Key Features of the Method. Identifies river and lake features indicative of poor and bad status that are due to hydromorph pressures. Approach is used in tandem with pre-existing and revised Environmental Standards. Allows the UK environment agencies to prioritise action on the most damaged water-bodies.

5 Broad Approach DRIVER PRESSURE STATE IMPACT RESPONSE Human need for clean water and electricity Abstraction and impoundment Habitat State: Size Connectivity Juxtaposition Character/ Diversity Response of organisms & ecosystems: e.g. fitness, abundance, resilience, diversity, composition, Active management of water resources ECOLOGICAL INDICATORS OF SEVERE IMPACTS WATER RELEASE OPTIMISATION FRAMEWORK

6

7 A conceptual model of stepped changes in macroinvertebrate assemblage composition in response to declining water levels in a river Prevalence of pond skaters. Large bodied predators Aerial respiration Standing water communities Chironomids- Haemoglobin

8 Typical Pressure Response Relationship

9 PRESSURES Abstraction and impoundment Catchment features Reality is a little more complicated HYDRAULIC e.g. Wetted perimeter, water depth, current velocity, power, shear stress HABITAT STATE GEOMORPHOLOGICAL e.g. Channel and bed structure Aquatic habitat size Connectivity and juxtaposition Character and quality of functional habitat Shelter, protection, breeding STATES Emergent properties = Ecological Indicators IMPACTS Organisms and ecosystems IMPACTS Emergent properties = Ecological Indicators Physicochemical processes Biological processes

10

11 Feature Review Overview Spatial scale- micro-catchment Temporal scale- transient-permanent Impact of temperature River Type Variation- is the response uniform Ecological Indicator Potential Suggested Indicators of poor & bad status

12 Indicative Assessment of Indicators Indicator number Indicator description Driver application from Conceptual Model River type specificity Potential confounding factors 1a Loss or absence of wetted channel. Absence of water in a river channel Steady abstraction, spray irrigation, direct supply reservoir (water & HEP), regulating reservoir (water & HEP). Not natural winterbournes Natural drying, sinks (e.g. karstic streams) and winterbournes. Caution if used in extreme droughts 1b Fragmentation of aquatic habitat in river channels Steady abstraction, spray irrigation, direct supply reservoir (water & HEP), regulating reservoir (water & HEP). Not natural winterbournes Natural sinks (e.g. karstic streams) and winterbournes. Artificial structures (e.g weirs). Caution use in extreme droughts 1c Loss of riffles/ runs, preponderance of pools Steady abstraction, spray irrigation, direct supply reservoir (water & HEP), regulating reservoir (water & HEP). Not natural winterbournes or large lowland rivers Natural sinks (e.g. karstic streams) and winterbournes. Caution if used in extreme droughts 1d Fine sediment covering sensitive habitats (riffles, runs, glides) Steady abstraction; spray irrigation; direct supply reservoir(water & HEP), Gravel and cobble bed rivers Excessive inputs of fine sediment from the catchment

13 Indicator number Indicator description Driver application from Conceptual Model River type specificity Potential confounding factors 2a Trout and salmon (0+ to 2+) absent in otherwise suitable and accessible habitat as assessed by appropriate model. Steady abstraction, water supply and HEP reservoir All except lowland floodplain rivers Trout are considered more reliable indicators than salmon given their ubiquity 2b Increased growth rate of trout Water supply reservoir All except lowland floodplain rivers Further development needed to establish reference growth rates at different sites 2c Decreased growth rate of trout Water supply and HEP reservoir All except lowland floodplain rivers Further development needed to establish reference growth rates at different sites 2d Absence of adult salmon or migratory trout in autumn Steady abstraction, water supply reservoir Upland spate rivers 2e Increased ratio of plantspawning to gravelspawning coarse fish Steady abstraction; spray irrigation; direct supply reservoir Chalk streams and lowland rivers. Excl. N.Ireland, much of Scotland.

14 Indicator number Indicator description Driver application River type specificity Potential confounding factors Link to Conceptual Model detailed evidence base 3a Major reduction in taxon richness Steady abstraction, regulating reservoir (HEP), spray irrigation, direct supply reservoir (water & HEP), regulating reservoir (water) All rivers Water pollution. Artificial physical modification of the channel I.22 3b LIFE O/E >0.914 using RIVPACS III+ or RICT and family LIFE Steady abstraction, regulating reservoir (HEP), spray irrigation, direct supply reservoir (water & HEP), regulating reservoir (water) LIFE not tested in Scotland or Northern Ireland Water pollution. Artificial physical modification of the channel I.22 3c Abundance of large bodied predatory invertebrates, such as Coleoptera larvae and adults (especially Dytiscidae), Hemiptera (Notonectidae, Corixidae and Gerridae) and Odonata nymphs in main river channel Steady abstraction, regulating reservoir (HEP), Spray irrigation, direct supply reservoir (water & HEP), regulating reservoir (water) All rivers Washout from local still waters during floods. Do not include if present only in natural backwaters or vegetated margins of rivers. Can colonise river reaches rapidly in response to seasonal low flows and drought. Need to compare to local reference sites and use in combination with other ecological indicators of chronic impacts. I.22

15 Characterisation of Indicators Physical Character- Diversity of habitat, Character of Habitat, Size Volume of Habitat, Connectivity Flow Character- Extreme and extended low Q, enhanced and stabilised flows, loss of small floods, loss of large floods Practical Application- Walk-over survey, Aerial survey, Sampling

16 Certainty of Indicators Established but incomplete 5b 4m 4a 6c 5a 4j 3c 4e 4l 4n 3f 4f 1k 4b 3h 4d 1j Evidence Virtually certain 4c 6b 3b 1f Well established 3d 3e 1a 1c 1b 1r 1g Speculative 1o 1p 1q 1l 3g Speculative 6a 1h 2d 4k 1i 1s Certainty Extremely unlikely 4g 2f 2g 2c 2a 2b 2e 1n Well established 1d 2h 1e 4i 4h 1m Competing explanations

17 Currently Trialling Recommendations on use will follow Removing week indicators Confirming application The weather!!!!!

18 Good/Poor Status Impact on fisheries Loss of water to other users Dilution capacity reduced. Reduced amenity value Flood risk displacement Enhanced erosion rates Disruption to migration Intrinsic and utilitarian value is reduced Legal imperative

19 Impact on Classification Improved certainty in water-bodies that are at Poor/Bad & Moderate Status Can t state with any certainty what the direction of travel will be as trial is still underway.