Role of high frequency water quality analysis in confirming catchment hydrology interpretation Michael DONN, Olga BARRON, Tony BARR CSIRO Land and Water, Australia
Introduction Nutrient export to the Swan Canning Estuary Hydrology is complex Seasonally variable Groundwater and wetlands Urban land use superimposed Temporal variation in nutrient concentrations Impact of catchment hydrology on export spatial iland temporal
Southern River catchment Southern River catchment ~20 km SE of Perth Area: 155 km 2 Land use: Peri urban TP inputs to Swan Canning Estuary 221t 2.21 t TP yr 1 1 (SCWQIP) Groundwater surface rfacewater interaction model (MODHMS) Extensive water quality monitoring
Wungong griver sub catchment
Wungong griver sub catchment Area 55 km 2 Area 55 km Steep upland areas
Wungong griver sub catchment Area 55 km 2 Steep upland areas Flatlowland lowland areas Seasonal wetlands
Wungong griver sub catchment Area 55 km 2 Steep upland areas Flatlowland lowland areas Seasonal wetlands Urban development (Wungong Urban Waters)
Wungong griver sub catchment Area 55 km 2 Steep upland areas Flatlowland lowland areas Seasonal wetlands Urban development (Wungong Urban Waters) MODHMS groundwater surface water interaction ti model
Hydrological model MODHMS Process based model (1997 2008) Coupled surface water and groundwater Sub surface fluxes (saturated and unsaturated) Overland flow Channel flow Vegetation (canopy interception and transpiration) Discretisation Spatial: Cell spacing 83 m Temporal: Daily time step
Wungong griver sub catchment In-situ High Frequency Water Quality Analyser Coastal plain water quality Outlet 0.06 mg/l Total P Shallow groundwater 0.67 mg/l Total P Surface water 0.28 mg/l TP (wetland) 2.5 mg/l TP (stream)
High frequency water quality data logger On site high frequency measurement phosphorus Mini- Analyser TRP telemetry flood plain Instrument parameters 2 hourly TRP measurements 15 min in-situ sensors dial-up access to instrument automated data delivery chemical delivery and waste removal mini-analyser water intake In-situ measurements ph, EC, DO, temperature, turbidity, tubdty, water level e
HFWQ: Flow and TRP temporal variability Flow 120 90 60 daily flow (ML) 30 MODHMS 0 Apr May Jun Jul Aug Sep Oct Nov Dec 2008
HFWQ: Flow and TRP temporal variability 0.20 120 ily TRP (mg g/l) 015 0.15 0.10 Flow TRP 90 60 daily flow (ML) Mean dai 0.05 30 MODHMS 0.00 0 Apr May Jun Jul Aug Sep Oct Nov Dec 2008
Modelled: Sub catchment flow Monthly flow (ML L) 3000 2500 2000 1500 1000 500 Total flow WUW 0 97 98 99 00 01 02 03 04 05 06 07 08 09
0.0 0.5 1.0 1.5 2.0 Modelled: Surface saturation May 2008 HIGH LOW GW level (mbgl) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan 2.5
0.0 0.5 1.0 1.5 2.0 Modelled: Surface saturation June 2008 HIGH LOW GW level (mbgl) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan 2.5
0.0 0.5 1.0 1.5 2.0 Modelled: Surface saturation July 2008 HIGH LOW GW level (mbgl) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan 2.5
0.0 0.5 1.0 1.5 2.0 Modelled: Surface saturation August 2008 HIGH LOW GW level (mbgl) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan 2.5
0.0 0.5 1.0 1.5 2.0 Modelled: Surface saturation September 2008 HIGH LOW GW level (mbgl) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan 2.5
0.0 0.5 1.0 1.5 2.0 Modelled: Surface saturation October 2008 HIGH LOW GW level (mbgl) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan 2.5
Surface saturation and TRP flux ly TRP (mg/l L) Mean dai 0.20 0.15 0.10 0.05 Flow TRP 0.00 Apr May Jun Jul Aug Sep Oct Nov Dec
2008 Mass balance Time Flow TRP Days % of Volume % of Load Yield total (ML) total (kg) (kg/ha) Hills 244 93 4368 67 153 004 0.04 WUW 23 7 327 33 76 021 0.21 Total 244 4695 229
Conclusions In situ HFWQ High temporal resolution BUT still a point measurement Hydrological modelling Where the water is coming from and when Integration of HFWQ and hydrological modelling Understanding of P transport processes Used for management and to evaluated impact of urbanisation
CSIRO Land and Water Michael Donn Environmental Chemist Phone: +61 8 9333 6146 Email: Michael.Donn@csiro.au au Web: www.csiro.au/science/urbanwater.html