Advancing catchment science through high-frequency monitoring of water quality

Transcription

1 Advancing catchment science through high-frequency monitoring of water quality Professor Kevin Hiscock School of Environmental Sciences University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ 8 July 2014

2 Outline The problem diffuse water pollution from agriculture Introduction to the Demonstration Test Catchments Project Water quality data resolution monthly, daily & sub-daily sampling Exceedance curves and water quality standards Conceptual model insights Solute flux calculations Data presentation & archiving

3 Mueller et al. (2012) Nature 490:

4 Challenge no. 1 Global distribution of >400 eutrophication-associated dead zones mapped against the global human footprint 1,2 1 Diaz & Rosenberg (2008) 2 Sanderson et al. (2002)

5 Catchment pollution sources

6 The Demonstration Test Catchments The DTC project aims to evaluate the extent to which on-farm mitigation measures can cost-effectively reduce the impacts of water pollution on river ecology while maintaining food production capacity

7 Wensum catchment location and conceptual model Rainfall

8 Storm event 27 November 2012 View 1 (Wood Dalling) Stream B Stinton Hall Farm Monitoring Station Stream A

9 View 1 (Wood Dalling) 27 November 2012

10

11 Blackwater sub-catchment study area

12 Hydro-meteorology weather station & rain gauge

13 Water quality monitoring - mini kiosk installation Taking half hourly measurements of: DO ph Conductivity Chlorophyll a Temperature Turbidity Stage ISCO automatic sampler to be triggered during storm events

14 Water quality monitoring - high spec kiosk installation Mains power Total and dissolved phosphorus analyser Pump Automatic water sampler Telemetry system Flow cell with multiparameter sonde and nitrate probe

15 Nitrate (mg N/L) Nitrate (mg N/L) Nitrate (mg N/L) Monthly grab sample data Tat Tatterford Common Wensum - Helhoughton Bridge Wensum - Swanton Morley

16 Nitrate (mg N/L) Nitrate (mg N/L) Nitrate (mg N/L) Weekly grab sample data Tat - Tatterford Common Wensum - Helhoughton Bridge Wensum Swanton - Morley Bridge

17 Data trends Stinton Hall Farm, E

18 NO 3 exceedance curve Stinton Hall E, April 2011 Dec 2012 EU Drinking Water Directive/NVZ limit Kiosk data: 8.7% of the monitoring period with concentrations >50 mg/l Grab sample data: exceedance recorded once A concentration frequency target may be more meaningful ecologically than average concentrations or loads as it relates directly to the duration of exposure of aquatic organisms to N, P and sediment

19 Total P exceedance curve Stinton Hall E, April 2011 Dec 2012 Kiosk data: 21.5% of the monitoring period with concentrations >100 mg P L -1 Grab sample data: 11.6% exceedance Environment Agency and Natural England target for main Wensum SSSI g_fen_dwpp_finalversion.pdf

20 Example monitoring data - Stinton Hall Farm, E - October 2013 Rainfall = mm Water level (m) Nitrate-N, TP, TRP (mg/l)

21 Detection of road salt runoff at Swanhills A 20 November 2012 Water temp. (min) = 5.20 o C Pathway to Swanhills A EC peak = 1142 ms/cm (3-hour lag) Air temp. (min) = o C Rainfall = 2.2 mm

22 Diurnal patterns Stinton Hall, Site E

23 Low, mid and high flow conditions Oct 2011 Sept 2012

24 Annual contribution to flow and pollutant loads under low, mid and high flow conditions Oct 2011 Sept 2012 N.B. Gaps in phosphorus record are likely to mean that there is an underestimation of the high-flow contribution Flow

25 Inter-annual comparison Park Farm, F Oct- Dec 2011 Total rainfall 120 mm Total N lost 2916 kg (5.4 kg/ha) Total P lost 31 kg (0.06 kg/ha)

26 Inter-annual comparison Park Park Farm, Farm, F Oct- April Dec Total rainfall 243 mm Total 65% N lost higher 15,378 N loss kg 5.3 times more N than 2011 (equivalent to 13,032*) (28.6 kg/ha) *NH 3 NO 3 at 300/tonne 21% higher P loss Total P lost 180 kg 5.8 times more P than 2011 (0.33 kg/ha)

27 Data presentation via Wensum Alliance website

28 Data presentation via Google earth application

29 Data retrievable at the original level of aggregation. Information accessible via intelligent queries that combine multiple datasets (and subsets) in novel ways. Intelligent restructuring of data via the use of linked data architecture. Fully compliant with EU INSPIRE Directive. Linkable with EU and international datasets via Link Data.

30 Summary & Reflections High-frequency monitoring provides unprecedented information on catchment processes (sources, mobilisation, pathways and delivery mechanisms). Field-based bankside systems require constant attention a rigorous maintenance schedule is required to keep sensors in working order. Data quality control and archiving is a demanding task. Web-based sensor technology provides greater certainty in supporting an evidenced-based approach to implementing agri-environmental policy.