Hydrology GL PDF

WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT WISSEN TECHNIK LEIDENSCHAFT Hydrology GL 2.1 The Water Cycle...

WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT WISSEN TECHNIK LEIDENSCHAFT Hydrology GL 2.1 The Water Cycle 2  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT ied) Interflow odif 8 -11 m 0 15- (20 ip. com eryh :// gall h ttp Dirk Muschalla 3  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT More Detailed Water Cycle 9 9) (19 nn ma O ber ki und ws O stro Dirk Muschalla 4  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT More Detailed Water Cycle 1 Atmospheric humidity circulation 2 Precipitation 3 Evaporation of raindrops 4 Evapotranspiration 5 Evaporation of water from depressions and surfaces 6 Evaporation of water from lakes 7 Evaporation of flowing surface water 8 Evaporation of oceanic water 9 Actual precipitation hitting the earth‘s surface 10 Non-intercepted precipitation 11 Surface runoff 12 Runoff of rivers and creaks 13 Water withdrawal of plants from saturated ground Dirk Muschalla 5  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT More Detailed Water Cycle 14 Water withdrawal of plants from unsaturated ground 15 Infiltration of depressions and surfaces 16 Exchange between groundwater from unsaturated zones and lake water 17 Exchange between ground- and lake water 18 Exchange between groundwater from unsaturated zones and river water 19 Exchange between ground- and river water 20 Runoff into the oceans 21 Infiltration into the unsaturated ground zone 22 Infiltration into the saturated ground zone 23 Percolation from the unsaturated into the saturated zone 24 Capillary rise from the saturated into the unsaturated zone 25 Exchange between ground- and ocean water 26 Deep infiltration Dirk Muschalla 6  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT The Water Cycle in Austria Precipitation Total evaporation ~ 1100 mm ~ 500 mm Evaporation: Surface runoff ~ 9 mm Unproductive ~ 95 mm Productive ~ 390 mm Agricultural and withdrawal ~ 6 mm Inflow from abroad Runoff to abroad ~ 320 mm ~ 920 mm Subterranean runoff to abroad ~ 30 mm Withdrawal Withdrawal Withdrawal industry households agriculture ~ 20 mm ~ 8 mm ~ 2 mm Wastewater industry Wastewater households ~ 18 mm ~ 6 mm Dirk Muschalla 7  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT WISSEN TECHNIK LEIDENSCHAFT Hydrology 2.2 Hydrological Processes 8  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Precipitation Forms of precipitation: § Rain § Snow http://en.anawalls.com (2015-08-11) § Hail § Sleet Measured as height in mm Dirk Muschalla 9  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Interception Plants and trees intercept raindrops Reduces surface runoff http://nj401.blogspot.co.at/2009/04/070409-geog-lesson-d.html (2015-08-11) Dirk Muschalla 10  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Evaporation Water returns to Atmosphere Slow process influenced by: § Saturation deficit § Wind speed § Global radiation Measured as height in mm Dirk Muschalla 11  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Transpiration Plants withdraw water from the ground Water evaporates into http://kitchenpantryscientist.com (2015-08-11) the atmosphere The term evapotranspiration is usually used to sum up evaporation and transpiration Dirk Muschalla 12  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Storage Surface water that is stored in non-moving water bodies http://www.fuerthermoar.at (2015-08-12) like lakes, oceans, etc. Dam for the hydropower plant Kaprun in Salzburg, Austria Dirk Muschalla 13  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Surface Runoff Surface water that is neither stored nor infiltrated into the http://www.zukunfteuropa.at (2015-08-11) ground Moves along the surface as rivers or creaks River flooding during a flood of 2005 in Tyrol and Vorarlberg Dirk Muschalla 14  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Infiltration Surface water seeps into the ground Agglomerated used in modified separated http://www.dredgdikes.eu (2015-08-11) sewer systems Also used to accumulate groundwater (northern Graz) Seepage reservoir to infiltrate rainwater into the ground Dirk Muschalla 15  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Percolation Water movement within the ground in unsaturated zones From the surface to the groundwater level http://www.annabelle.ch (2015-08-11) Dirk Muschalla Filter coffee demonstrates percolation 16  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Interflow and baseflow Interflow: Flow between surface and groundwater table Baseflow: Flow within the groundwater vSurface runoff > vInterflow > vBaseflow Dirk Muschalla 17  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT WISSEN TECHNIK LEIDENSCHAFT Hydrology 2.3 Water Balance Dirk Muschalla 18  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Water balance General equation for water balance: P = E + Q + ΔS P Precipitation [mm] E Evapotranspiration [mm] Q Runoff [mm] ΔS Change in storage [mm] (negligible in the long term) Dirk Muschalla 19  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Water balance Common mistakes: Mixing different units Missing parts of the equation Wrong signs: Inflow and runoff always as absolute values dS > 0 when storage is filled dS < 0 when storage is emptied Rules for braces as known: a – (b + c) = a – b – c Dirk Muschalla 20  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Climate types derived from the water balance humid climate all year P > E semi-humid climate P > E with periods of E > P semi-arid climate E > P with periods of P > E arid climate E > P (desert zones) nival climate characterized by snow and ice Dirk Muschalla 21  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT WISSEN TECHNIK LEIDENSCHAFT Hydrology Water Balance – Example 1 Dirk Muschalla 2 3 WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Water balance General equation for water balance: P = E + Q + ΔS P Precipitation [mm] E Evapotranspiration [mm] Q Runoff [mm] ΔS Change in storage [mm] (negligible in the long term) Dirk Muschalla 3 4 WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Water balance Common mistakes: Mixing different units Missing parts of the equation Wrong signs: Inflow and runoff always as absolute values dS > 0 when storage is filled dS < 0 when storage is emptied Rules for braces as known: a – (b + c) = a – b – c Dirk Muschalla 4 5 WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Water balance – Example 1 A hydropower plant is planned at a waterbody with a catchment area of 125 km². Years of measurement show a yearly precipitation of 812 mm and an evapotranspiration of 435 mm for the catchment area. What is the expected runoff (in m³/s) not accounting the change in storage? Dirk Muschalla 5 6 WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Water balance – Example 1 A hydropower plant is planned at a waterbody with a catchment area of 125 km². Years of measurement show a yearly precipitation of 812 mm and an evapotranspiration of 435 mm for the catchment area. What is the expected runoff (in m³/s) not accounting the change in storage? P = E + Q + ΔS Yearly values -> ΔS = 0 P=E+Q P = 812 mm/a E = 435 mm/a Q = P – E = 812 mm/a – 435 mm/a = 377 mm/a Dirk Muschalla 6 7 WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Water balance – Example 1 A hydropower plant is planned at a waterbody with a catchment area of 125 km². Years of measurement show a yearly precipitation of 812 mm and an evapotranspiration of 435 mm for the catchment area. What is the expected runoff (in m³/s) not accounting the change in storage? Q = P – E = 812 mm/a – 435 mm/a = 377 mm/a Q = 377 mm/a * 1/1000 m/mm = 0,377 m/a Q = 0,377 m/a * 125 km2 * 106 m2/km2 Q = 47.125.000 m³/a Dirk Muschalla 7 8 WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Water balance – Example 1 A hydropower plant is planned at a waterbody with a catchment area of 125 km². Years of measurement show a yearly precipitation of 812 mm and an evapotranspiration of 435 mm for the catchment area. What is the expected runoff (in m³/s) not accounting the change in storage? Q = 47.125.000 m³/a *1/(365*24*60*60) a/s Q = 1,49 m³/s Dirk Muschalla 8  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT WISSEN TECHNIK LEIDENSCHAFT Hydrology Water Balance – Example 2 Dirk Muschalla 9 10 WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Water balance – Example 2 Catchment area with 124 km², 82 km² of which are forest, rest is in agricultural use. Mean precipitation: 815 mm/a Mean evapotranspiration: 600 mm/a (forest) 460 mm/a (agriculture) Mean flow (MQ) at level measurement: 1.52 m³/s Dirk Muschalla 10 11 WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Water balance – Example 2 Catchment area with 124 km², 82 km² of which are forest, rest is in agricultural use. Mean precipitation: 815 mm/a Mean evapotranspiration: 600 mm/a (forest) 460 mm/a (agriculture) Mean flow (MQ) at level measurement: 1.52 m³/s a) Which mean amount of wastewater in m³/s is discharged in creek 1? b) What is the natural runoff [l s-1 km-2] of the catchment area? Dirk Muschalla 11 12 WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Water balance – Example 2 Catchment area with 124 km², 82 km² of which are forest, rest is in agricultural use. Mean precipitation: 815 mm/a Mean evapotranspiration: 600 mm/a (forest) 460 mm/a (agriculture) Mean flow (MQ) at level measurement: 1.52 m³/s a) Which mean amount of wastewater in m³/s is discharged in creek 1? b) What is the natural runoff [l s-1 km-2] of the catchment area? P = 815 mm/a * 1/1000 m/mm = 0,815 m/a P = 0,815 m/a * 124 km2 * 106 m2/km2 P = 101.060.000 m³/a Eforest = 0,6 m/a * 82 km2 * 106 m2/km2 Eforest = 49.200.000 m³/a Dirk Muschalla 12 13 WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Water balance – Example 2 Catchment area with 124 km², 82 km² of which are forest, rest is in agricultural use. Mean precipitation: 815 mm/a Mean evapotranspiration: 600 mm/a (forest) 460 mm/a (agriculture) Mean flow (MQ) at level measurement: 1.52 m³/s a) Which mean amount of wastewater in m³/s is discharged in creek 1? b) What is the natural runoff [l s-1 km-2] of the catchment area? P = 101.060.000 m³/a Eforest = 49.200.000 m³/a Eagri = 0,46 m/a * 42 km2 * 106 m2/km2 Eagri = 19.320.000 m³/a Dirk Muschalla 13 14 WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Water balance – Example 2 Catchment area with 124 km², 82 km² of which are forest, rest is in agricultural use. Mean precipitation: 815 mm/a Mean evapotranspiration: 600 mm/a (forest) 460 mm/a (agriculture) Mean flow (MQ) at level measurement: 1.52 m³/s a) Which mean amount of wastewater in m³/s is discharged in creek 1? b) What is the natural runoff [l s-1 km-2] of the catchment area? P = 101.060.000 m³/a, Eforest = 49.200.000 m³/a, Eagri = 19.320.000 m³/a MQ = 1,52 m3/s * 365 * 24 * 60 * 60 s/a MQ = 47.934.720 m³/a Dirk Muschalla 14 15 WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Water balance – Example 2 Catchment area with 124 km², 82 km² of which are forest, rest is in agricultural use. Mean precipitation: 815 mm/a Mean evapotranspiration: 600 mm/a (forest) 460 mm/a (agriculture) Mean flow (MQ) at level measurement: 1.52 m³/s a) Which mean amount of wastewater in m³/s is discharged in creek 1? b) What is the natural runoff [l s-1 km-2] of the catchment area? P = 101.060.000 m³/a, Eforest = 49.200.000 m³/a, Eagri = 19.320.000 m³/a, MQ = 47.934.720 m³/a P + Qwastewater = Eforest + Eagri + MQ Qwastewater = Eforest + Eagri + MQ - P Qwastewater = 49.200.000 + 19.320.000 + 47.934.720 - 101.060.000 = 15.394.720 m³/a Dirk Muschalla 15 16 WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Water balance – Example 2 Catchment area with 124 km², 82 km² of which are forest, rest is in agricultural use. Mean precipitation: 815 mm/a Mean evapotranspiration: 600 mm/a (forest) 460 mm/a (agriculture) Mean flow (MQ) at level measurement: 1.52 m³/s a) Which mean amount of wastewater in m³/s is discharged in creek 1? b) What is the natural runoff [l s-1 km-2] of the catchment area? Qwastewater = 15.394.720 m³/a Qwastewater = 15.394.720 m³/a * 1/(365*24*3600) a/s Qwastewater = 0,488 m³/s Dirk Muschalla 16 17 WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Water balance – Example 2 Catchment area with 124 km², 82 km² of which are forest, rest is in agricultural use. Mean precipitation: 815 mm/a Mean evapotranspiration: 600 mm/a (forest) 460 mm/a (agriculture) Mean flow (MQ) at level measurement: 1.52 m³/s a) Which mean amount of wastewater in m³/s is discharged in creek 1? b) What is the natural runoff [l s-1 km-2] of the catchment area? MQ = 1,52 m³/s, Qwastewater = 0,488 m³/s Natural runoff = (1,52 m³/s - 0,488 m³/s) / 124 km2 Natural runoff = 0,008 m3/(s*km2) Natural runoff = 0,008 m3/(s*km2) * 1000 l/m3 Natural runoff = 8 l/(s*km2) Dirk Muschalla 17  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT WISSEN TECHNIK LEIDENSCHAFT Hydrology Water Balance – Example 3 Dirk Muschalla 18 19 WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Water balance – Example 3 Given data from a 6-month long monitoring campaign § Mean inflow: 2.35 m³/s § Mean runoff: 2.28 m³/s § Precipitation: 462 mm § Evapotranspiration: 510 mm § Water level of the lake at the start: 324.43 maA § Water level of the lake at the end: 325.60 maA Does the lake withdraw water from the groundwater or does the lake’s water seep into the aquifer? Dirk Muschalla 19 20 WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Water balance – Example 3 Qin = 2.35 m³/s, Qout =2.28 m³/s, P = 462 mm, E = 510 mm Water level start = 324.43 maA, Water level end: 325.60 maA Vin = 2.35 m³/s * 365/2 * 24 * 60 * 60 s = 37.054.800 m³ Vout = 2.28 m³/s * 365/2 * 24 * 60 * 60 s = 35.951.040 m³ P = 462 mm * 1/1000 m/mm * 112 ha * 10000 m2/ha = 517440 m³ E = 510 mm * 1/1000 m/mm * 112 ha * 10000 m2/ha = 571200 m³ P + Vin = Vout + E + ΔS ΔS = P + Vin - Vout – E ΔS = 517440 + 37054800 - 35951040 – 571200 = 1050000 m3 Δm = 1050000 m3 / (112 ha * 10000 m2/ha) = 0,94 m 324.43 maA + 0,94 m = 325,37 maA < 325.60 maA Vin,groundwater = (325,6-324,43-0,94 m) * 112 ha * 10000 m2/ha = 257600 m3 Dirk Muschalla 20  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT WISSEN TECHNIK LEIDENSCHAFT Hydrology 4.1 Precipitation Dirk Muschalla  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Definition Precipitation is water of the http://en.anawalls.com (2015-08-11) atmosphere that falls (falling precipitation) or already fell (fallen precipitation) to the ground due to gravitation after condensation or sublimation. Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Characteristics Precipitation can be characterized by: § Height hP § Duration DP § Intensity iP § Local distribution § Type Precipitation is measured as volume over an area. Therefore its unit usually is mm. Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Catchment area Hydrological catchment area: Area from which the water flows to a specified location Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Exercise – Design of a catchment area Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Measuring Precipitation Concentrated measurement (point measurement) with a rain gauge § 200 - 400 cm² surface § Usually 1 m above ground level § No obstructions around the measurement § Protection against vandalism Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Rain gauges Standard rain gauge Tipping bucket Rain scale Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Areal precipitation with rain gauges Can the areal and temporal distribution be derived from a single rain gauge? representative for 200 cm² > 100 km² Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Measuring errors for point measurements Error types: § Technical measuring error § Wind influence § Evaporation loss Example for a minor successful setup General errors: § 10 – 20% for rain § 25% for snow Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Precipitation Radar This technology sends out micro waves. Some of these waves are reflected by rain, snow or ice. The time the wave needs to return defines the distance of the obstacle. This technology only gives information about intensity. For accurate measurements it needs to be calibrated with point measurement systems on the ground. Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Precipitation Radar Rain gauge Radar Measuring principle direct indirect snapshot at specific Temporal monitoring continuous moments Spatial monitoring point measurement comprehensive Precipitation amount volume (variable 200 - 400 cm² with regard to parameter) Error margin miscellaneous error sources Data availability spatially distributed at one place Rainfall prediction conditionally possible possible Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Precipitation radar § Correction with offline calibration § Calibration with point measurements Rain gauge Precipitation radar Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Precipitation measurement network Graz § 6 institutions § 24 point measurements § Data agglomeration at a single location § Just in time data transfer § (Automated validation) Besitzer Austro Control Holding Graz - Wasserwirtschaft Land Steiermark - Hydrographischer Dienst Stadt Graz - Grünraum und Gewässer TU Graz Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering ZAMG  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT WISSEN TECHNIK LEIDENSCHAFT Hydrology 4.2 Average Areal Precipitation Dirk Muschalla  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Areal precipitation without precipitation radar Rain gauges Catchment area Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Methods to calculate the areal precipitation § Arithmetic mean § Thiessen-Polygon-Method § Geo-Gridding-Method (Grid-Point-Method) § Isohyetal method Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Arithmetic mean Used for flat catchment areas with equally distributed precipitation: $ 1 𝑃! = $ ∗ 𝑃! 𝑛 !"# Only consider gauges that are within the catchment area! Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Exercise – Arithmetic Mean The rain gauges S1-S6 measured the following daily totals (the grid size is 1 km) Rain gauge P [mm] S1 25 S2 40 S3 30 S4 50 S5 35 S6 30 Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Exercise – arithmetic mean $ 1 1 1 1 ! 𝑃 = $ ∗ 𝑃! = ∗ 40 𝑚𝑚 + ∗ 30 𝑚𝑚 + ∗ 50 𝑚𝑚 = 40 𝑚𝑚 𝑛 3 3 3 !"# Rain gauge P [mm] S1 25 S2 40 S3 30 S4 50 S5 35 S6 30 Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Thiessen-Polygon-Method Division of the catchment area in areas with similar precipitation S2 S1 $ A2 𝐴! A1 𝑃! = $ ∗ 𝑃! 𝐴%&%'( A3 !"# A4 S3 S4 Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Exercise – Thiessen-Polygon-Method Find the mean precipitation using the Thiessen-Method S2 Rain gauge P [mm] S1 S1 22 S2 20 S3 27 S4 20 S3 S4 Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Exercise – Thiessen-Polygon-Method S2 S1 S3 S4 Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Exercise – Thiessen-Polygon-Method S2 S1 A2 A1 A3 A4 S3 S4 Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Exercise – Thiessen-Polygon-Method Rain gauge P [mm] Area A [ha] S1 22 8 S2 20 15 S3 27 10 S4 20 12 $ 𝐴! 𝑃! = $ ∗ 𝑃! = 𝐴%&%'( !"# 8 15 10 12 = ∗ 22 𝑚𝑚 + ∗ 20 𝑚𝑚 + ∗ 27 𝑚𝑚 + ∗ 20 𝑚𝑚 = 45 45 45 45 = 21.9 𝑚𝑚 Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Exercise – Thiessen-Polygon-Method (2) The rain gauges S1-S6 measured the following daily totals (the grid size is 1 km) Rain gauge P [mm] S1 25 S2 40 S3 30 S4 50 S5 35 S6 30 Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Exercise – Thiessen-Polygon-Method (2) Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Exercise – Thiessen-Polygon-Method (2) A2 A1 A3 A4 A5 A5 Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Exercise – Thiessen-Polygon-Method (2) A2 A1 A3 A4 A5 A5 Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Exercise – Thiessen-Polygon-Method (2) A2 A1 A3 A4 A5 A5 Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Exercise – Thiessen-Polygon-Method (2) A2 A1 A3 A4 A5 A5 Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Exercise – Thiessen-Polygon-Method (2) A2 A1 A3 A4 A5 A5 Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Exercise – Thiessen-Polygon-Method (2) A2 A1 A3 A4 A5 A5 Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Exercise – Thiessen-Polygon-Method (2) A2 A1 A3 A4 A5 A5 Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Exercise – Thiessen-Polygon-Method (2) A2 A1 A3 A4 A5 A5 Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Exercise – Thiessen-Polygon-Method (2) Rain gauge P [mm] Area A [km²] S1 25 6 S2 40 13 S3 30 16 S4 50 16 S5 35 7 S6 30 6 $ 𝐴! 𝑃% = ( ∗ 𝑃! = 𝐴%&%'( !"# 6 13 16 16 7 6 = ∗ 25 𝑚𝑚 + ∗ 40 𝑚𝑚 + ∗ 30 𝑚𝑚 + ∗ 50 𝑚𝑚 + ∗ 35 𝑚𝑚 + ∗ 30 𝑚𝑚 = 64 64 64 64 64 64 = 37.1 𝑚𝑚 Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Geo-Gridding-Method à Grid-Point-Method 1. Insert a grid over the catchment area 2. Calculate the precipitation values for the crossings using the inverse distance method with the 4 closest rain gauges 1 ∑+# 𝑃! ∗ , 𝑑! 𝑃)* = + 1 ∑# , 𝑑! A(xA, yA): Coordinates of the position to calculate P(xP, yP): Coordinates of a rain gauge Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Geo-Gridding-Method à Grid-Point-Method d(P,A): Direct distance between the current position and the rain gauge d(P, A) = 𝑥- − 𝑥. , + 𝑦- − 𝑦. , 3. Calculate the precipitations of the grid area’s by calculating the arithmetic means with the 4 precipitations of each area’s corners 4. Calculate the weighed mean precipitation of the entire catchment using the means of the grid areas from above. Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Exercise – Grid-Point-Method The rain gauges S1-S6 measured the following daily totals (the grid size is 1 km) Rain gauge P [mm] S1 25 S2 40 S3 30 S4 50 S5 35 S6 30 Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Exercise – Grid-Point-Method % & $"# #"% = &"!"% ' + &(!" % ' = (#"' !" % & $ '# #"% = &"!"% ' + &(!"% ' = (#"' !" % & $ $# #"% = &$!"% ' + &'!"% ' = $#!"!" % & $ (# #"% = &'!" % ' + &$!" % ' = $#!"!" Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Exercise – Grid-Point-Method 1 ∑+# 𝑃! ∗ 𝑑!, 𝑃)* = = 1 ∑+# , 𝑑! 1 1 1 1 , ∗ 25 𝑚𝑚 + , ∗ 40 𝑚𝑚 + , ∗ 30 𝑚𝑚 + , ∗ 50 𝑚𝑚 4.12 𝑘𝑚 4.12 𝑘𝑚 3.61 𝑘𝑚 3.61 𝑘𝑚 = = 1 1 1 1 , + , + , + 3.61 𝑘𝑚 , 4.12 𝑘𝑚 4.12 𝑘𝑚 3.61 𝑘𝑚 𝑚𝑚 9.96 = 𝑘𝑚, = 36.7 𝑚𝑚 1 0.271 𝑘𝑚, Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Isohyetal Method 1. Draw lines of equal precipitation 2. Multiply the areas alongside the lines (0.5 above and 0.5 below) with the corresponding average precipitations 3. Sum the gained values to get the total precipitation 4. Divide the sum by the total area to get the average precipitation Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Exercise – Isohyetal Method Calculate the mean precipitation for the catchment area of a river with an area of 165.5 km². Rain P gauge [mm/d] A 80 B 70 C 50 D 40 E 30 Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering October 11, 2024 44 WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Exercise – Isohyetal Method Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Exercise – Isohyetal Method Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Exercise – Isohyetal Method Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Exercise – Isohyetal Method N [mm/d] A [km²] 80 11.4 75 23.7 65 20.9 55 27.9 45 31.9 35 37.8 30 11.9 Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  WISSEN ⋅ TECHNIK ⋅ LEIDENSCHAFT Exercise – Isohyetal Method ∑$!"# 𝑁! ∗ 𝐴! 𝑃! = = ∑$!"# 𝐴! 80 ∗ 11.4 + 75 ∗ 23.7 + 65 ∗ 20.9 + 55 ∗ 27.9 + 45 ∗ 31.9 + 35 ∗ 37.8 + 30 ∗ 11.9 = = 165.5 = 52.56 𝑚𝑚/𝑑 Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering  www.tugraz.at n SCIENCE n PAS S I O N n TECHNOLOGY 5.1 Evapotranspiration - Intro Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering u www.tugraz.at  www.tugraz.at n evaporation definitions § evaporation: during temperatures below the boiling point water changes fom liquid or solid state into gaseous state (water vapour) § a significant water loss from drainage basins is called evapotranspiration (ET) § evapotranspiration consists of two sub-processes § evaporation (E) § transpiration (T) 2  www.tugraz.at n evaporation definitions § evaporation: escape of water molecules based on physical laws § from open water surface § from non vegetated earth‘s surface § from wet surface of plants § transpiration: loss of water vapour through aerial parts of plants into the atmosphere 3  www.tugraz.at n evaporation definitions § actual evapotranspiration is the ET of a partly or entirely plant covered area whose water supply is limited by lack of water, biological an physical conditions § potential evapotranspiration occurs without such limitation. It is defined as the amount of evaporation under given meteorogical circumstances that would occur with unlimited water supply 4  www.tugraz.at n evaporation purpose of determining evaporation § climate models and weather forecast § water balance determination § Temporally an spatial low resoluted data § agriculture § information for short time intervals § construction industry § desiccation of soil at dam and road construction 5  www.tugraz.at n evaporation medium annual evaporation in Eastern Styria source: Endbericht Nanutiwa, 1995 6  www.tugraz.at n evaporation definitions evaporation depends physically on four factors: § difference between the water vapour pressure at the evaporating surface and that of the surrounding atmosphere § availabiliy of energy at the surface § amount of water vapour transported in the air § amount of water available at the surface or transported there 7  www.tugraz.at n evaporation linking of water and energy budget atmosphere water supply energy supply evaporation real water supply real energy supply vegetation soil location factor source: Dyck und Peschke 8  www.tugraz.at n evaporation water budget ! + " + # + !$ = ! P: precipitation E: evapotranspiration R: runoff ΔW: change of water storage in soil source: DVWK, 1996; Dietrich,2010 9  www.tugraz.at n evaporation energy budget "! + # + $ + %& = ! Rn : net radiation H: sensible heat G: soil heat flux LE: latent heat flux source: DVWK, 1996; Dietrich,2010 10  www.tugraz.at n evaporation linking of water and energy balance Climate / weather water balance energy balance sensible heat flow precipi- evaporation net tation radiation runoff change of soil storage soil heat flow 11  www.tugraz.at n Dirk Muschalla, Institute of Urban Water Management and Landscape Water 12  www.tugraz.at n SCIENCE n PAS S I O N n TECHNOLOGY 5.2 Evapotranspiration - Measurement Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering u www.tugraz.at  www.tugraz.at n determination of evaporation methods according DVWK-M 238 § direct measurement methods § indirect measurement methods § calculation methods § from open water surface § from non vegetated earth‘s surface § from vegetated earth‘s surface § as potential evapotranspiration § as actual evapotranspiration 14  www.tugraz.at n determination of evaporation direct measurement methods § soil moisture method: locations away from groundwater with only vertical humidity exchange § soil moisture is extracted just by infiltration or evaporation § infiltration only above field capacity; during dry period soil moisture is extracted just by evaporation 15  www.tugraz.at n determination of evaporation direct measurement methods § evaporation pan #$ = " " !! § Lysimeter $%" = # " "& " !! source: Dyck, 1996 16  www.tugraz.at n determination of evaporation direct measurement methods evaporation pan #$ = " " !! 17  www.tugraz.at n determination of evaporation direct measurement methods precipitation rain gauge evapotranspiration gauge lysimeter well body Soil moisture scale 18  www.tugraz.at n determination of evaporation direct measurement methods (weighing) lysimeter $%" = # " "& " !! 19  www.tugraz.at n determination of evaporation direct measurement methods § useless for practical purposes (i.e. the determination of evaporation of heterogeneous surfaces) § basis is the water budget equation; knowing all parameters by direct measurement methods the only unknown parameter ‘evaporation’ can be calculated § suitable for site investigations with individual stations 20  www.tugraz.at n Dirk Muschalla, Institute of Urban Water Management and Landscape Water 21  www.tugraz.at n SCIENCE n PAS S I O N n TECHNOLOGY 5.3 Evapotranspiration – Indirect Measurement and Calculation Dirk Muschalla, Institute of Urban Water Management and Landscape Water Engineering u www.tugraz.at  www.tugraz.at n determination of evaporation indirect measurement methods § on the basis of the causal connection between direct measured meteorological parameters and the water vapour transport in the surface near air layer § impractical method with high measurement effort of physical and meteorological parameters § e.g. micrometeorological measurements as such of water vapour flow of vaporising surfaces 23  www.tugraz.at n determination of evaporation calculation of evapotranspiration The essential parameters to calculate the evapotranspiration are: § the temperature § the relative air humidity to describe the saturation deficit § the wind as indicator for regional air exchange § the sunshine duration distinguished are: § mass balance methods § energy balance methods § combined methods 24  www.tugraz.at n determination of evaporation calculation of evaporation of water surfaces ► abundant water is available, i.e. potential evaporation ist actual evaporation § mass balance methods § aerodynamic or Dalton method § energy balance methods § diverse methods § combined methods § Penman method 25  www.tugraz.at n determination of evaporation calculation of evaporation of land surfaces § distinction between calculation of potential and actual evaporation source: DVWK M 238 26  www.tugraz.at n determination of evaporation Haude - method calculation of monthly sum of potential evapotranspiration (ETP) #$) = "&"'E! " (!% ! ! ) aHaude: empirical monthly plant factor es-e: saturation deficit of air with water vapour in hPa !"#$%& ! #" ! # = () ! $% * " "%#!$' " )+$ " # ! + "!"%#' RH: relative air humidity [-] T: temperature [°C] 27  www.tugraz.at n calculation of potential evaporation Haude - method aHaude: empirical monthly plant factor Tabelle 5.2.: monthly plant factors to calculate evaporation (by Löpmeier 1994) cultural plants jan feb mar apr may jun jul aug sep oct nov dec winter rap 0,18 0,18 0,20 0,32 0,37 0,35 0,26 0,20 0,18 0,18 0,18 0,18 rye 0,18 0,18 0,20 0,30 0,38 0,36 0,28 0,20 0,18 0,18 0,18 0,18 winter wheat 0,18 0,18 0,19 0,26 0,34 0,38 0,34 0,18 0,18 0,20 0,18 0,18 spring barley 0,15 0,15 0,18 0,25 0,30 0,36 0,26 0,25 0,23 0,22 0,22 0,20 grass 0,20 0,20 0,21 0,29 0,29 0,28 0,26 0,25 0,23 0,22 0,22 0,20 corn 0,15 0,15 0,18 0,18 0,18 0,26 0,26 0,26 0,24 0,21 0,14 0,14 sugar beets 0,15 0,15 0,18 0,15 0,23 0,30 0,36 0,32 0,26 0,19 0,14 0,14 source: www.hydroskript.de 28  www.tugraz.at n calculation of potential evaporation exercise During a hydrological year the following climate data were measured in a catchment area. The annual potential evaporation [mm] has to be calculated by the Haude method. month nov dec jan feb mar apr may jun jul aug sep oct T [°C] 3,5 2,5 1,0 1,5 4,5 10,5 13,1 17,1 21,2 19,2 15,3 10,9 RH[%] 92 89 80 64 62 59 57 55 53 65 40 52 aHaude 0,22 0,22 0,22 0,22 0,27 0,29 0,29 0,28 0,26 0,25 0,23 0,22 source: www.hydroskript.de 29  www.tugraz.at n calculation of potential evaporation exercise During a hydrological year the following climate data were measured in a catchment area. The annual potential evaporation [mm] has to be calculated by the Haude method. month nov dec jan feb mar apr may jun jul aug sep oct T [°C] 3,5 2,5 1,0 1,5 4,5 10,5 13,1 17,1 21,2 19,2 15,3 10,9 RH[%] 92 89 80 64 62 59 57 55 53 65 40 52 aHaude 0,22 0,22 0,22 0,22 0,27 0,29 0,29 0,28 0,26 0,25 0,23 0,22 es-e ETP [mm/d] number of days ETP [mm/month] 30  www.tugraz.at n calculation of potential evaporation exercise During a hydrological year the following climate data were measured in a catchment area. The annual potential evaporation [mm] has to be calculated by the Haude method. month nov dec jan feb mar apr may jun jul aug sep oct T [°C] 3,5 2,5 1,0 1,5 4,5 10,5 13,1 17,1 21,2 19,2 15,3 10,9 RH[%] 92 89 80 64 62 59 57 55 53 65 40 52 aHaude 0,22 0,22 0,22 0,22 0,27 0,29 0,29 0,28 0,26 0,25 0,23 0,22 es-e 0,63 0,80 1,31 2,45 3,20 5,20 6,47 8,76 11,82 7,77 10,41 6,25 ETP [mm/d] 0,14 0,18 0,29 0,54 0,86 1,51 1,88 2,45 3,07 1,94 2,40 1,37 number of days 30 31 31 28 31 30 31 30 31 31 30 31 ETP [mm/month] 4,14 5,48 8,95 15,09 26,76 45,22 58,18 73,59 95,23 60,26 71,85 42,62 solution: ETP = 507 mm/year 31  www.tugraz.at n determination of evaporation Penman-method combined equation derivated from energy balance methods and aerodynamic methods for water surfaces $ 'G ! & $ E+!G,-G = " + " # "# ! " (!) (" ) ! ! ) $ +$ % $ +$ s gradient of the saturated vapour pressure curve g psychrometer constant Rn radiation balance G soil heat flux L specific heat of evaporation of 1 mm evaporation height F(u) function dependent on wind velocity u and on vegetation height es(T) – e saturation deficit, dependent on air temperature T and vapour pressure e source:www.hydroskript.de ► required input data usually not available 32  www.tugraz.at n SCIENCE n PAS S I O N n TECHNOLOGY hydrology infiltration Prof.Dirk Muschalla - Institut für Siedlungswasserwirtschaft und Landschaftswasserbau u www.tugraz.at  www.tugraz.at n soil texture definitions § soil texture is determined by size and type of particles § size of particles § fine sand 0,02 to 0,2 mm § silt 0,002 to 0,02 mm § clay < 0,002 mm § Sand: small surface area, low ability to retain moisture, low nutrient bonding § Silt: low nutrient bonding, limited air and water movement § Clay: large surface area, high ability to retain moisture, good nutrient bonding Prof.Dirk Muschalla - Institut für Siedlungswasserwirtschaft und Landschaftswasserbau 2  www.tugraz.at n soil texture triangle definition § The soil texture triangle defines names associated with various combinations of sand, silt and clay. § f.e. a soil with 30% clay, 50% sand and 20% silt is called a sandy clay loam Prof.Dirk Muschalla - Institut für Siedlungswasserwirtschaft und Landschaftswasserbau 3  www.tugraz.at n soil texture triangle definition source: http://mea.com.au/ Prof.Dirk Muschalla - Institut für Siedlungswasserwirtschaft und Landschaftswasserbau 4  www.tugraz.at n soil structure definition § Soil structure is the arrangement of particles in different aggregates which differ from each other in shape, size, stability and degree of adhesion. source: http://mea.com.au/ Prof.Dirk Muschalla - Institut für Siedlungswasserwirtschaft und Landschaftswasserbau 5  www.tugraz.at n soil moisture definitions § the amount of water stored in the soil is based on § amount of precipitation § proportion of precipitation infiltrating into the soil § capacity of soil to store water § the available water capacity is § the maximum amount of plant available water § an indicator of a soil‘s ability to retain water for plant use § the water held in soil between its field capacity and permanent wilting point Prof.Dirk Muschalla - Institut für Siedlungswasserwirtschaft und Landschaftswasserbau 6  www.tugraz.at n soil water storage definitions § the field capacity is § the water remaining in a soil after it has been saturated and allowed to drain freely (for 1 or 2 days) § The moisture content of soil after complete percolation § the permanent wilting point is § the minimal content of soil moisture the plants require not to wilt Prof.Dirk Muschalla - Institut für Siedlungswasserwirtschaft und Landschaftswasserbau 7  www.tugraz.at n soil water storage Prof.Dirk Muschalla - Institut für Siedlungswasserwirtschaft und Landschaftswasserbau 8  www.tugraz.at n Movement of water definitions § infiltration is the movement of water through the soil surface into the soil § percolation is the movement of water through the soil, the downward movement of water through the unsaturated zone Prof.Dirk Muschalla - Institut für Siedlungswasserwirtschaft und Landschaftswasserbau 10  www.tugraz.at n infiltration definitions § the infiltration of rain falling upon the ground into the subsurface soil § reduces the amount of runoff § delayes the runoff § Increases the recharge of groundwater § provides the vegetation with necessary soil moisture § the infiltrationrate is [mm/h] depends on § precipitation (intensity, duration, local distribution) § soil surface (slope, roughness, vegetation) § soil type (size, shape and distribution of pore space) § actual soil moisture Prof.Dirk Muschalla - Institut für Siedlungswasserwirtschaft und Landschaftswasserbau 11  www.tugraz.at n infiltration definitions § depending on soil structure and soil moisture the infiltrated water splits in different parts: § one part increases the soil moisture. By way of vegetation and soil evaporation it enters the atmosphere again § one part reaches (delayed in time) by interflow on subsurface ways the surface water; it never reaches the ground water § one part percolates the unsatured soil zone and recharges the ground water. Delayed in time it finally reaches the surface water Prof.Dirk Muschalla - Institut für Siedlungswasserwirtschaft und Landschaftswasserbau 12  www.tugraz.at n infiltration definitions source: ………………………………. Prof.Dirk Muschalla - Institut für Siedlungswasserwirtschaft und Landschaftswasserbau 13  www.tugraz.at n infiltration measurement § double ring infiltrometer § to create a one-dimensional flow of water from the inner ring; the outer ring acts as a barrier to encourage only vertical flow from the inner ring § to determine the infiltration rate is [mm/h] by measuring the descent rate of the water level in the inner ring § by testing several areas it is possible to find the maximum infiltration rate of a large tract Prof.Dirk Muschalla - Institut für Siedlungswasserwirtschaft und Landschaftswasserbau 14  www.tugraz.at n infiltration measurement § double ring infiltrometer source: http://hydropedologie.agrobiologie.cz/ Prof.Dirk Muschalla - Institut für Siedlungswasserwirtschaft und Landschaftswasserbau 15  www.tugraz.at n infiltration measurement § results for infiltration rate measured by double ring infiltrometer infiltration class infiltration rate is [mm/h] soil type 1 very low 254 gravel, grit Prof.Dirk Muschalla - Institut für Siedlungswasserwirtschaft und Landschaftswasserbau 16  www.tugraz.at n SCIENCE n PAS S I O N n TECHNOLOGY hydrology runoff Prof.Dirk Muschalla - Institut für Siedlunsgwasserwirtschaft und Landschaftswasserbau u www.tugraz.at  www.tugraz.at n runoff definitions § runoff § that part of precipitiation appearing as streamflow § amount of water throughflowing a river crosssection per time unit [L3/T] e.g. [m3/s] § specific runoff § discharge per unit area of a drainage basin § quotient of runoff and drainage basin [L3/(TxL2)] = [L/T] e.g. [l / s·km2] oder [mm/a] Prof.Dirk Muschalla - Institut für Siedlunsgwasserwirtschaft und Landschaftswasserbau 2  www.tugraz.at n runoff measurement methods § direct measurement § measurement of water level and direct hydraulic conversion § weir, Venturi tube § measurement of water level and conversion using the relation water level to runoff § staff gauge, river gauge § measurement of flow velocity related to the river corsssection § current meter, ultrasonic measurement § measurement by tracer Prof.Dirk Muschalla - Institut für Siedlunsgwasserwirtschaft und Landschaftswasserbau 3  www.tugraz.at n runoff measurement direct measurement § instant measurement of runoff only in case of small amounts of discharge (e.g. spring) § method: measurement by bucket („Auslitern“) § the volume of water V collected in a certain time period dt provides the runoff Q = V / dt Prof.Dirk Muschalla - Institut für Siedlunsgwasserwirtschaft und Landschaftswasserbau 4  www.tugraz.at n runoff measurement indirect method measurement by weir measurement by Venturi tube source: http://bfw.ac.at ► discharge is definitely dependent from water level source: DI C. Lüdecke Prof.Dirk Muschalla - Institut für Siedlunsgwasserwirtschaft und Landschaftswasserbau 5  www.tugraz.at n runoff measurement indirect method '"" water level &"DD()D#"*+,-.%,/0(),N2P &#" &"" ##" #"" %#" %"" $#" $"" &$! discharge !#" !"" &#! ()*& (()*& !()*& ()*' (()*' !()*' $()*' &"! &D()A**+,%-.*/ !"#$% &!! %! $! #! "!!! discharge curve "! ! ()&&*+&,)-./"0#/N2*+/PQ' *!! &'($ &&'($ "&'($ &'() &&'() "&'() *&'() )!! (!! !"#A% '!! &!! %!! $!! #!! "!! ! ! "!! #!! $!! %!! !"#$%&' Prof.Dirk Muschalla - Institut für Siedlunsgwasserwirtschaft und Landschaftswasserbau 6  www.tugraz.at n runoff measurement discharge – rating curve methods to measure the water level § non recording gauges (staff gauge) § float gauge / compressed air gauge § pneumatic gauge § radar / ultrasonic Prof.Dirk Muschalla - Institut für Siedlunsgwasserwirtschaft und Landschaftswasserbau 7  www.tugraz.at n runoff measurement discharge – rating curve measuring the water level by staff gauge source: Holtorff, 1995 Prof.Dirk Muschalla - Institut für Siedlunsgwasserwirtschaft und Landschaftswasserbau 8  www.tugraz.at n runoff measurement discharge – rating curve Measuring the water level by float gauge source: Holtorff, 1995 Prof.Dirk Muschalla - Institut für Siedlunsgwasserwirtschaft und Landschaftswasserbau 9  www.tugraz.at n runoff measurement discharge – rating curve measuring the water level by compressed air gauge Prof.Dirk Muschalla - Institut für Siedlunsgwasserwirtschaft und Landschaftswasserbau 10  www.tugraz.at n runoff measurement measurement of flow velocity methods to measure the water level current meter acustic flowmeter electromagnetic flowmeter Mobile Doppler flowmeter source: www.ott.com Prof.Dirk Muschalla - Institut für Siedlunsgwasserwirtschaft und Landschaftswasserbau 11  www.tugraz.at n runoff measurement current meter Prof.Dirk Muschalla - Institut für Siedlunsgwasserwirtschaft und Landschaftswasserbau 12  www.tugraz.at n runoff measurement current meter Prof.Dirk Muschalla - Institut für Siedlunsgwasserwirtschaft und Landschaftswasserbau 13  www.tugraz.at n runoff measurement measurement of flow velocity § basing on the continuity equation Q = v · A § flow velocity non constant over the river cross section § cross section subdevided into areas § velocity v registered in each measuring vertical Prof.Dirk Muschalla - Institut für Siedlunsgwasserwirtschaft und Landschaftswasserbau 14  www.tugraz.at n runoff measurement measurement of flow velocity § subdivison into measuring verticals § verticals in characteristic profile points § different area width allowed § measuring vertical i in the middle of the area § six point method § 6 measuring points per vertical: in 20%, 40%, 60% and 80% of water level h and near surface and ground $#" = &%$! #$" % & ! + " ! $" %&% " ! + " ! $" % &% ) ! + " ! $" % &%( ! + " ! $" % &%' ! + $" %! ! %! = A"! ! #! with A! = #! ! "! and $" = &%"$ ! #$" %()*% + " ! $" %&"''() + $" %!"#$% ! Prof.Dirk Muschalla - Institut für Siedlunsgwasserwirtschaft und Landschaftswasserbau 15  www.tugraz.at n runoff measurement measurement of flow velocity current meter equation: !$% = # ! "$% + !! § vij: velocity in measuring point j of the vertical i [m/s] § nij: cycle per second in measuring point j of the vertical i [1/s] § a: pitch of the current meter screw [m] = 0,4 m § v0: compension value caused of bearing friction [m/s] = 0,05 m/s Prof.Dirk Muschalla - Institut für Siedlunsgwasserwirtschaft und Landschaftswasserbau 16  www.tugraz.at n runoff measurement measurement of flow velocity ultrasonic-Doppler- measurement boat Prof.Dirk Muschalla - Institut für Siedlunsgwasserwirtschaft und Landschaftswasserbau 17  www.tugraz.at n runoff measurement measurement of flow velocity flow velocity profile Prof.Dirk Muschalla - Institut für Siedlunsgwasserwirtschaft und Landschaftswasserbau 18  www.tugraz.at n runoff measurement measurement of flow velocity ultrasonic measurement (duration with / against flow direction) Prof.Dirk Muschalla - Institut für Siedlunsgwasserwirtschaft und Landschaftswasserbau 19  www.tugraz.at n runoff measurement by tracer source: www.hydroskript.de " !# ! ! # ! " ! !" + "# ! !# = $" + "# # ! !! " = "# " "!$ ! !# ! Prof.Dirk Muschalla - Institut für Siedlunsgwasserwirtschaft und Landschaftswasserbau 20  www.tugraz.at n runoff measurement exercise: current meter To determine a river‘s runoff a flow current meter was used. The measurement results of vertical 5 and 6 are presented in this table. See the measurement setup in the following draft. Prof.Dirk Muschalla - Institut für Siedlunsgwasserwirtschaft und Landschaftswasserbau 21  www.tugraz.at n runoff measurement exercise: current meter To determine a river‘s runoff a flow current meter was used. The measurement results of vertical 5 and 6 are presented in this table. See the measurement setup in the following draft. Prof.Dirk Muschalla - Institut für Siedlunsgwasserwirtschaft und Landschaftswasserbau 22  www.tugraz.at n runoff measurement exercise: current meter Which value has the maximum flow velocity in vertical 5? !$% = # ! "$% + !! a = 0,4 m v0 = 0,05 m/s Prof.Dirk Muschalla - Institut für Siedlunsgwasserwirtschaft und Landschaftswasserbau 23  www.tugraz.at n runoff measurement exercise: current meter Which value has the maximum flow velocity in vertical 5? !$% = # ! "$% + !! #)*+ # = "$(" ! (&'# ! %" ! ) + "$"#" ! ! #%&' " = $#""" ! ! a = 0,4 m v0 = 0,05 m/s Prof.Dirk Muschalla - Institut für Siedlunsgwasserwirtschaft und Landschaftswasserbau 24  www.tugraz.at n SCIENCE n PAS S I O N n TECHNOLOGY Hydro