Upmanu Lall Columbia University

1. Upmanu Lall Columbia University Hydromorphology or Hydrology in an Ever Changing World: Role of water in planetary evolution at time scales of centuries to millenia

2. Example Questions motivating Hydromorphology • How has water influenced the history of man and life on Earth? • How has man determined the history, distribution and pathways of water? • How have climate variations and change determined water and life at different scales, places and times? • How has water constrained and determined climate? • When/how will the human induced hydrologic change dominate that due to climate, and in turn determine aspects of regional and global climate change and variability? • How can we assess or predict a hydrologic future for the 21st century to address impending concerns of water stress for man and life given potentially dramatic hydrologic changes due to changes in seasonal and long term climate variability and to human factors? • How will we manage such changes?

3. A Semi-classical View Nonstationarity? Design: Long Term Risk Management Manage Variability Operation: Manage Residual Risk Society Goals Hydrology Structure Curiosity Processes Dynamics Evolution Planetary Context (bio-geo-human-systems) Do we have satisfactory models for long term evolution? Fluid Mechanics Knowledge Stochastic Processes Challenges: 1. Spatial Heterogeneity, Scales & Continuum, Structure of Turbulence/Transport 2. Long Term Evolution (not much literature, except for climate) Open or Closed System? Strong Feedbacks with other earth systems

4. A Restricted View of the Earth System Climate Dynamics Ocean-Atmosphere Dynamics Weather Ecological Dynamics Geomorphology Land Use Dynamics Other processes* Demographics Social Dynamics Think about actual processes involved  time and space scales, thresholds, intermittent or continuous * e.g., Tectonic activity, uplift

5. A Restricted View of the Earth System Climate Dynamics Ocean-Atmosphere Dynamics Weather Hydrology Ecological Dynamics Geomorphology Land Use Dynamics Other processes* Demographics Social Dynamics Think about actual processes involved  time and space scales, thresholds, intermittent or continuous

6. A Restricted View of the Earth System Climate Dynamics Hydromorphology Ocean-Atmosphere Dynamics Weather Hydrology Ecological Dynamics Geomorphology Land Use Dynamics Other processes* Demographics Social Dynamics Orgaqnization time and space scales, thresholds, intermittent or continuous dynamics, system/state boundaries

7. Typical Model Structure • Non-Autonomous Forced Dynamical System • A number of inter-acting stores  state variables • Forced by exogenous variables that are time varying (continuous or intermittent) • Spatially averaged, discrete or continuous time • Focus (often): Fluxes, Patterns, Mean Residence Times Does this system have interesting dynamics? Suppose we think of this system as a RLC network Are the internal dynamics of x dominated by y?  dynamics of y? Analogies -- Role of R? C? L? Are there strong +ve and –ve feedbacks across x Nonstationarity in x  changes in y, changes in θ, changes in f(.,.,.) or all

8. Hydrology as practiced • Dominant interest in • Mean value – statistics of state variables • Stimulus response modeling (spatial emphasis, short term) • Event Models • Continuous Simulation Models • Components can often be decomposed into separate models • Slow components (e.g. groundwater) modeled separately (forced by fast component model) and provide initial conditions for stimulus-response of faster component • Cumulative effects modeling is unidirectional and naïve – model formulation does not explicitly consider full dynamics or interactions across interfaces • Long term Dynamics – either in terms of statistical properties of state variables or parametrically determined by statistical properties of exogenous variables • No good paradigm available for modeling long term dynamics including feedbacks across key exogenous variables at appropriate space and time scales (we are in a discovery phase)

9. Hydrology “open terrestrial system” hillslope/basin scales response function to forcing forecasts from initial and boundary value problems Prescribed topography, soils, vegetation, use, climate (rain, etc) => Stationary* probability distributions whether the problem is treated deterministically or statistically Hydromorphology Interacting planetary “stores”  hierarchy  “closed system?” Regimes in space-time, predictability, transition, stability Parametric evaluation of boundary value problems Boundary conditions/interfaces evolve -- coupled => “holistic?” view of global and local hydrologic cycle and its dependence on changing conditions  non-stationary, unless conditional probability From hydrology to hydromorphology Weather Climate

10. Non-Autonomous Forced Dynamical System Example: River Basin Hydromorphology – Water and Humans But …. Now x includes human population state variables, technology, infrastructure and income state variables as endogenous to the system Human, infrastructure and river networks interact to prescribe both the evolution of the water state variables and the networks themselves Prediction examples: Long term evolution of population patterns in the river basin Long term evolution of water and other infrastructure Changing biota and landscape

11. Non-Autonomous Forced Dynamical System? Planetary Hydromorphology Now – as far as the water cycle is concerned, we could have closure but many, many other “cycles” have to be accounted for interactions across all planetary stores human dynamics accounted for as endogenous External forcing is solar radiation Example prediction problems: Gaia – Symbiosis across vegetation, atmosphere and humans through water? Population density – spatial and temporal variations The Greenhouse, the Thermohaline Conveyer, Abrupt Climate Change

12. Floods (extremes in a changing world) • Local Changes in Flood Frequency due to Urbanization/Land Use Change etc • Climate induced Changes in Floods 

13. Floods in a changing climate Nature, 2002

14. Nature, 2003

15. Russian River, CA Flood Event Russian River, CA Flood Event of 18-Feb-04 Atmospheric River generates flooding CZD Slide from Paul Neiman’s talk Russian River flooding in Monte Rio, California 18 February 2004 IWV (cm) GPS IWV data from near CZD: 14-20 Feb 2004 Bodega Bay Atmospheric river IWV (cm) IWV (inches) Cloverdale photo courtesy of David Kingsmill 10” rain at CZD in ~48 hours

16. 10 largest Floods 10 smallest Floods Washington Oregon N. California C. California S. California SST Composites for Extreme Floods Coast of Western US Look for what happens by latitude 60 years per station, 50 stations

17. Wavelet Analysis of 1000 year sample of annual maximum NINO3 from a 110,000 year integration of the Cane-Zebiak Model with stationary forcing ( Clement and Cane, 1999)

18. The Colorado River Compact (1922) 2005 Headline

19. Hydrologic/Climatic Variability

20. Severity and Frequency of Colorado River Compact Failure (w/ and w/o Lake Powell) Colorado River Compact Failure WITH Lake Powell Colorado River Compact Failure in the Absence of Lake Powell Relative Variance 1 5 10 20 30 80 100 200 Recurrence Period

21. River Basins and Humans (population density) – is there a connection?Feedbacks?Co-evolution?

22. Development Trajectories in River Basins Development Utilization Allocation Hypothesis: In a given climate and technology, position on the river network has been a determinant of human population and its infrastructure development Role of mean supply vs role of variability in space and time

23. Human Hydrology Climate  • Scale and Direction of Human Feedbacks Most ecological species (w/o predators) have population growth dynamics that are not too different from logistic, with carrying capacity determined by local resources. Is water a likely resource constraint? If yes, is it a local or global constraint? How is it manifest? Scoping the feedback, as a function of scale……….

24. Diffuse Porous Ring Porous Average Daily Vapor Pressure Deficit (kPa) From: S. Bush & D. Pataki Urban Forest Management (evapotranspiration rates) • Ring Porous Wood Only • assume 15 sq mi forest SLC • ~3 MG per day • SLC indoor ~44 MG per day Source: Craig Forster

25. Marshall et al, 2001 S. Florida – draining the swamps changes regional moisture recycling -- desertification

26. Water Table Decline >400 ft Rivers have undergone significant degradation in flow and quality as well Width of Ganges at the confluence with Yamuna is now typically 3 to 4 km smaller With all these benefits, it is not surprising that farmers and entrepreneurs have invested around US$12 billion in groundwater pump structures. This sum is huge, especially when compared with the US$20 billion of public money spent on surface-water irrigation schemes over the last 50 years

27. Large Scale Irrigation changes the Monsoon?

28. Irrigation  changed water vapor flux

30. A Proposal to Link Major Indian River Systems: $160 Billion Capital Cost 33 Dams (9 Major) 30 Major Canals covering 12,500km 34 million hectares to be irrigated (12x Area of Bangladesh) =30% of current 34GW of hydropower Flood Control Navigation

31. VIRTUAL WATER FLOWS (1995)measured in crop ET, cereals EU (15) excluding intra-trade

32. VIRTUAL WATER FLOWS (2025)measured in crop ET, cereals

33. Research Questions developed by the hydromorphology working group Primary Challenge: What is important, when, where and how? • How to develop and test a suitable low order dynamical modeling system to understand the currency of water in global evolution • How can data sets be developed to support hypothesis development for long term evolution of the Gaia system • How can we learn and build from integrated hydrology structure-evolution modeling and data sets Decomposition of Climate and Human Factors: • Low frequency climate oscillations translate into systematically changing frequency and intensity of precipitation and aquifer recharge/discharge. • How are these manifest in natural and modified hydrology in different climate zones? • What are the dominant frequencies of response of different hydrologic components? • How do they depend on spatial scale and the spatial distribution of development in the system? • What are key climatic or development thresholds that lead to abrupt hydrologic change?

34. Questions continued • Water and the Development of Societies – Agent/Environment Interaction: • Does human “control” and development of surface and subsurface water fluxes superposed on the pattern of climatic exigencies lead to emergent and predictable patternsor cycles of infrastructure development, hydrologic modification and climate impact? • Is the observed scaling of population density with area related to position on the drainage network, and the seasonal and interannual variation of hydrologic fluxes over the drainage network? • What is the role played by agriculture and ecosystems in determining water use and human population density? • How does the population distribution and scaling with area change as storage infrastructure and other technological innovations change the variability and scaling of hydrologic fluxes with area? • From Human to Water to Climate: • How have regional hydrologic changes induced by human activity modified regional climate? • How does changing planetary temperature, terrestrial biota and land use translate into changes in atmospheric water composition and the hydrologic cycle? • How do these changes determine a future planetary climate?