Summer Synthesis Institute Vancouver, British Columbia June 22 – August 5 Overview of Synthesis Project Synthesis Project Descriptions Summer Institute Logistics

Water Cycle Dynamics in a Changing Environment: Advancing Hydrologic Science through Synthesis Murugesu Sivapalan Praveen Kumar, Bruce Rhoads, Don Wuebbles University of Illinois Urbana, Illinois

Session 2 Suresh Rao Purdue University Nandita Basu University of Iowa Contaminant Dynamics across Scales: Temporal and Spatial Patterns Aaron Packman Northwestern University

 Non linear filters create emergent patterns/signatures across scales  Signatures integrate ecosystem structure and function  Relationship of water flow and water quality to stream ecosystems  Examining signatures using data analysis and models Conceptual Model Cascading Controls

Overall Hypothesis Despite process complexity at the local scale, non-linear interactions in the cascade of filters and buffers generate emergent spatio-temporal patterns or signatures that can be expressed as simple functions of the hydrologic and biogeochemical drivers of the system. 5

Emergent Patterns: Runoff Coefficient (RC) and Flow Duration Curve 6  Budyko Curve describes the mean annual streamflow across the climatic gradient  Botter et al. (2009) showed that FDC can be predicted as a simple analytical function of λ/k - λ (runoff frequency) - k (catchment mean residence time)  Runoff frequency can be expressed in terms of underlying soil vegetation and rainfall properties  Catchment mean residence time estimated from hydrograph recession curve analysis  Able to describe pdfs of streamflows across several catchments in US Inter-annual Intra-annual Slope = RC

7 Example 1: Emergent Pattern: LAPU and Load Duration Curve (LDC) 1.Formulate Hypotheses LDC is a function of  FDC since water carries the chemical  Chemical Properties (sorption, degradation, etc.)  Chemical input functions (atmospheric deposition vs. fertilizer application)  Landscape Biogeochemical Filter LAPU: Load as a Percent Used (analogous to RC) Slope = LAPU Inter-annual Intra-annual

Emergent Pattern: Load Duration Curve (LDC) 2. Run Model to explore dominant controls on LDC Two available transient hillslope-network coupled models - Model A (Reggiani et al.) Sheng Ye and Hongyi Li - Model B (Rinaldo et al.) Stefano Zanardo 3. Analyze data to explore dominant controls on LDC 4. Develop simple analytical approaches 5. Response to change

Hydrologic and Biogeochemical Filters Two Functions of Filters: 1.Decrease in mass - Hydrologic Filter: runoff coefficient - Biogeochemical Filter: load as a percent used 2. Alteration of the distribution: - relationship between flow distribution curve and rainfall duration curve (Hydrologic Filter) - relationship between load distribution curve and flow duration curve (Biogeochemical Filter)

Example 2: Biogeochemical Filter: Dual Duration Curve (DDC) What does the DDC depend on?

Biogeochemical Filter: Dual Duration Curve (DDC) A – nitrate B – atrazine Why is nitrate so different from atrazine? How can we classify chemicals or watersheds based on such signatures?

Mean Annual Patterns: Flow vs. Load Intra-annual patterns observed in DDC persists in the mean annual behavior…

13 Network Models: Spatial Patterns Nitrogen Yield kg/km 2

Objectives/Tasks (1) (1)Identify relevant hydrologic, biogeochemical and ecological signatures (2) Understand the functioning of the hydrologic and biogeochemical filters that modify the forcing functions (rainfall and chemical application) - Formulate hypotheses - Run model - Analyze Data (3) Develop simple analytical approaches to predict the signatures as a function of the key parameters of the filters and forcings (4) Identify how land use or climate change would alter the attributes of the filters, and thus change the signatures.

Data based Signatures Humid: Little Vermilion Watershed in Illinois: tile-drained agricultural watershed, approximately 480 km2 Arid: Avon River Basin in Western Australia: agricultural watershed of size 120,000 km2 We are searching for other catchments with water quality data --- suggest your favorite catchment Chemicals of interest: Dissolved (Nitrate, pesticides etc)

Key preparation work required 1.Read the papers and familiarize yourself with the primary assumptions in the two models 2.Question the assumptions and think what they would mean in terms of the observed signatures 3.Start thinking about the signatures and filters --- other interesting signatures or questions that you may want to explore 4.Read the questions/hypotheses in the framework and think about additional ones that you want to explore. 5.Contact me if you have or know of contrasting watersheds with water quality data More thinking than doing….