Water Balance Estimation Naomi Radke seecon international Gmb

Water Balance Estimation Naomi Radke, seecon international Gmb. H Water Balance Estimation

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Find this presentation and more on www. sswm. info Contents 1. What is a Water Balance Estimation 2. Who is Involved? 3. What Can it be Used for? 4. Uncertainty and Problems 5. Conducting a Water Balance Estimation 6. Applicability 7. Advantages and Disadvantages 8. References Water Balance Estimation 3

Find this presentation and more on www. sswm. info 1. What is a Water Balance Estimation? A water balance estimation is. . . A tool to assess the current status and trends in water resources availability in an area over a specific period of time. Change in global water availability. A water balance estimate can reveal the situation of water availability. Source: UNEP GRID-A (2009) Water Balance Estimation 4

Find this presentation and more on www. sswm. info 1. What is a Water Balance Estimation? Calculating the water balance The simplest form of water balance estimation is: P = Q + E ± ∆S P: Q: E: ∆S: Precipitation Runoff Evaporation Storage in the soil, aquifers or reservoirs Example of water balance estimation. Source: BGR (2008) Water Balance Estimation 5

Find this presentation and more on www. sswm. info 1. What is a Water Balance Estimation? Conservation of water. . . If in a specific area over a specific time water inflows = water outflows ± changes in storage Precipitation (rainwater) is either transferred to surface run off or evaporates OR it is stored in the ground. Water Balance Estimation 6

Find this presentation and more on www. sswm. info 2. Who is Involved? • Stakeholders involved in decision-making that require more detailed info on water available • Specialists or staff that have undergone training and access to specialist support River. Ware (a river system modelling tool)Training in Mexico. Source: Water Balance Consulting (2013). Water Balance Estimation 7

Find this presentation and more on www. sswm. info 3. What Can it be Used for? • Asses the current status and trends in water resource availability in an area over a specific period of time • Strengthen water management decision-making by assessing and improving the validity of visions, scenarios and strategies Managing aquifer recharge/discharge. Source: FAO et al. (2012) Water Balance Estimation 8

Find this presentation and more on www. sswm. info 4. Uncertainty and Problems Uncertainty in water balance estimation There is always uncertainty due to inadequate capture networks, measurement errors, complex spatial and temporal heterogeneity of hydrological processes ü Uncertainty Analysis is an important part of water balance estimation! Water Balance Estimation 9

Find this presentation and more on www. sswm. info 4. Uncertainty and Problems occurring in water balance estimation • Temporal and spatial boundaries are not defined • Quality of input data is poor • Double counting of water flows when water flows within an area added to water flow of exiting area • Inappropriate extrapolation of field level information to a larger scale • Intuition (often based on popular myths) is used rather than good quality information. • The storage term(s) of the water balance is omitted • Political or other pressures result in unreliable estimates that have been manipulated Water Balance Estimation 10

Find this presentation and more on www. sswm. info 5. Conducting a Water Balance Estimation Materials and Resources • Techniques: From very simple “back of the envelope” calculations to highly complex computer-based models • Precondition: Sound knowledge of hydrological processes • Advisable o To contract specialist service o To have access to a quality-controlled information database Water Balance Estimation 11

Find this presentation and more on www. sswm. info 5. Conducting a Water Balance Estimation Methods (1/2) • Step 1: Define boundaries of the area of interest • Step 2: Undertake a needs assessment of the water balance information that is required among stakeholders. Define water balance components of particular interest • Step 3: Produce a simply schematic diagram that shows storage, inflows and outflows from the area of interest • Step 4: Identify a source(s) of quality-controlled info, relevant for area and period Water Balance Estimation 12

Find this presentation and more on www. sswm. info 5. Conducting a Water Balance Estimation Methods (2/2) • Step 5: Uncertainty and sensitivity analysis on this info. If inadequacies, redefine the boundaries and/or modify equation • Step 6: Produce water balance estimates in a format that is useful for visioning, scenario building and planning with the community • Step 7: Control these estimates regarding their quality before they are disseminated • Step 8: Disseminate findings to stakeholders in a form they can understand Water Balance Estimation 13

Find this presentation and more on www. sswm. info 5. Conducting a Water Balance Estimation Result Example Australian water balance report. Source: NWC (2005) Water Balance Estimation 14

Find this presentation and more on www. sswm. info 6. Applicability Water balance estimation as basis for. . . • Quantitative evaluation of water resources and their change under human activities • Hydrological substantiation of projects for the rational use, control and redistribution of water resources in time and space How does irrigation effect the water availability? A water balance estimation can help assess the severity of human impact on the water cycle. Source: B. Haas Water Balance Estimation 15

Find this presentation and more on www. sswm. info 7. Advantages and Disadvantages Advantages: • Provides you with a comprehensive understanding of the water flow system and water resources in your area Water Balance Estimation Disadvantages: • Often incorrect for the many reasons listed before • Often, minimal or no account is taken of uncertainty when estimates are made and presented • Very complex work process that needs to be done by qualified experts (at least as support) which requires considerable time and resources 16

Find this presentation and more on www. sswm. info 8. References BGR (2008): Water Cycle/Water Balance for Germany. Hannover: Bundesanstalt fuer Geowissenschaften und Rohstoffe (BGR). URL: http: //www. bgr. bund. de/EN/Themen/Wasser/Bilder/Was_wasser_startseite_wasserkreis_g_en. html [Accessed: 14. 10. 2013] Water Balance Consulting (2013): River. Ware Simulation Training in Mexico. Boulder: Water Balance Consulting. URL: http: //waterbalance. org/projects-page/riverwaretraining/ [Accessed: 14. 10. 2013] FAO, GEF, IAH, IHP, World Bank (2012): Management of aquifer recharge and discharge processes and aquifer storage equilibrium. Rome: FAO. URL: http: //www. zaragoza. es/ciudad/medioambiente/onu/en/detalle. Per_Onu? id=587 [Accessed: 14. 10. 2013] NWC (Editor) (2005): Australian Water Resources 2005 - Water Balance Assessment. Canberra: Australian Government, National Water Commission (NWC). URL: http: //www. water. gov. au/Water. Availability/Waterbalanceassessments/index. aspx? Menu=Level 1_3_ 2 [Accessed: 14. 10. 2013] UNEP GRID-A (2009): The Contribution of Climate Change to Declining Water Availability. Arendal: United Nations Environment Programme (UNEP) GRID Arendal. URL: http: //maps. grida. no/go/graphic/the-contribution-of-climate-change-to-declining-water-availability [Accessed: 14. 10. 2013] Water Balance Estimation 17

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