1 / 38

Review of WA02 - Practical Lessons on Water Accounting

Explore the essential concepts of Water Accounting with Jeff Davids at TU Delft. This comprehensive review emphasizes the importance of measuring and estimating water fluxes and changes in storage to manage resources effectively. Key topics include precipitation mechanisms, streamflow measurements, and evapotranspiration methods, alongside practical tools like manual gauges and remote sensing technologies. As Lord Kelvin noted, “You can’t manage a resource you don’t measure,” making these lessons vital for sustainable water management practices.

gerald
Télécharger la présentation

Review of WA02 - Practical Lessons on Water Accounting

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Review of WA02 - Practical Lessons on Water Accounting Jeff Davids TU Delft | S4W | H2oTech

  2. “You can’t manage a resource you don’t measure.” - Lord Kelvin

  3. Water Accounting (WA) Source: Molden and Sakthivadivel 1999 and http://www.ruralwaterresources.com/wp-content/uploads/2013/09/Hydrological-Cycle.jpg

  4. Outline • Measuring or Estimating Fluxes and Changes in Storage • Partitioning Between WA Categories • Uncertainty in WA

  5. Outline • Measuring or Estimating Fluxes and Changes in Storage • Partitioning Between WA Categories • Uncertainty in WA

  6. Source: http://science.sciencemag.org/content/313/5790/1068.full

  7. Precipitation • Mechanisms of precipitation include: • Stratiform • Convective • Orographic Source:https://en.wikipedia.org/wiki/Precipitation

  8. Stratiform - Cold Front Source:http://apollo.lsc.vsc.edu/classes/met130/notes/chapter11/graphics/cf_xsect.jpg

  9. Stratiform - Warm Front Source:http://www.atmos.washington.edu/~hakim/101/fronts/ahrens_0818.jpg

  10. Convective Source:https://i.ytimg.com/vi/T9cKm8T_DD0/maxresdefault.jpg

  11. Orographic Source:https://i.ytimg.com/vi/T9cKm8T_DD0/maxresdefault.jpg

  12. S4W-Nepal Manual Gauges Onset Tipping Bucket DHM CoCoRaHS

  13. Radar (Doppler) • High energy microwave radio • Reflectivity measures intensity • Doppler shift measures velocity • Topography limits Source:weather.gov

  14. Remote Sensing • TRMM/GPM • GPM Microwave Imager (GMI) • Dual-Frequency Precipitation Radar (DPR) • Unprecedented data Source: https://www.nasa.gov/mission_pages/GPM/overview/index.html

  15. Streamflow Measurements • Water stage measurements + stage-discharge • Direct velocity measurements • Mechanical meters • Hydroacoustics • Surface radar velocimetry • Numerical modeling (e.g. rainfall - runoff) • Remote sensing

  16. Source: https://www.waterlog.com/

  17. Projects – GCID Gradient Facility and Drain Flow Measurements

  18. Evapotranspiration Measurements • Reference ET * Crop Coefficient (FAO 56) • Dependent on good land use land cover (LULC) data • Eddy Covariance • Lysimeters • DTS Bowen Ratio • Remote Sensing (e.g. SEBAL, METRIC, ETLook, etc.)

  19. FAO56 (Reference ET * Crop Coefficient) Source: www.fao.org/3/a-f2430e.pdf

  20. Lysimeters Source:https://commons.wikimedia.org/wiki/File:Lysimeter_g1.svg

  21. Vegetative index (e.g. NDVI, etc.) Sourcehttps://earthobservatory.nasa.gov/Features/MeasuringVegetation/measuring_vegetation_2.php

  22. Energy balance (e.g. SEBAL, MOD16, etc.) Source: WGM Bastiaanssen, M Menenti, RA Feddes, AAM Holtslag Journal of hydrology 212, 198-212

  23. Picture from NaarPhu and Tarai

  24. Change in Storage • Changes in groundwater storage, soil moisture, reservoirs, snow/ice, etc. • Measurements of groundwater table, reservoir levels, snow/ice depth, etc. • Measure pumping rates, recharge, etc.

  25. What Happens When Pump a Well? • Concept of Capture as formulated by Theis (1940) in his “The Source Of Water Derived From Wells.” • Well water comes from a combination of: • Change in Storage • Induced Recharge • Reduced Discharge • Capture = Sum of Induced Recharge and Reduced Discharge • Sustainable Capture: Concepts for Managing Stream Aquifer Systems (Davids and Mehl 2014) Source: Theis, 1940

  26. Groundwater - Surface Water Source: The Nature Conservancy

  27. Groundwater Storage - Storativity • “Storativity - the volume of water released from storage per unit decline in hydraulic head in the aquifer, per unit area of the aquifer.” Source:http://www.kgs.ku.edu/HighPlains/atlas/porfig.gif

  28. Groundwater Flow - Darcy’s Law • Q = K x A x dh/dl • Where: • K = Hydraulic conductivity (m/day) • A = Cross-sectional Area (m2) • dh = change in head (vertically) (m) • dl = horizonal distance (m) Source:http://blogs.egu.eu/network/geosphere/2013/09/

  29. Outline • Measuring or Estimating Fluxes and Changes in Storage • Partitioning Between WA Categories • Uncertainty in WA

  30. Partitioning Between WA Categories Process Non-Proc Beneficial Depleted Non-Ben Inflow Committed Outflow + = ΔS Non-Com Utilizable Outflow Non-Util Source: Molden and Sakthivadivel 1999

  31. Partitioning Between WA Categories Inflow (90) Depleted (60) Beneficial (40) Process (25) Gross Inflow Non-Process (15) Available Net Inflow Non-Beneficial (20) Outflow (40) Utilizable (10) • Uncommitted (20) Non-Utilizable (10) Committed (20) ΔS (10) Source: Molden and Sakthivadivel 1999

  32. Outline • Measuring or Estimating Fluxes and Changes in Storage • Partitioning Between WA Categories • Uncertainty in WA

  33. Uncertainty in Water Balances • To properly interpret Water Balances (WA), understanding uncertainty is critical! • Uncertainty in all measured/estimated fluxes propagates through to the “closure” term • Garbage In = Garbage Out • Uncertainty depends on data availability, methodology, etc.

  34. Uncertainty in Water Balances • Key Sources of Uncertainty • Measurement uncertainty (human and instrument) • Theoretical or empirical uncertainty (lack of complete understanding of processes) • Spatial uncertainty • Temporal uncertainty • Uncertainty can be random and systematic

  35. Questions and Discussion

More Related