Hydrologic Balance & Water Demands
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KAVALA INSTITUTE OF TECHNOLOGY School of Agricultural Technology Department of Forestry and Natural Environment Management MSc in Water Resources of the Mediterranean UrbanUrban SprawlSprawl ImplicationsImplications onon WaterWater ResourcesResources (3(3thth presentation)presentation) Lecturers: - Dr George D. Bathrellos - Dr Hara D. Skilodimou (Researchers & Part-Time Lecturers in National & Kapodistrian University of Athens Faculty of Geology & Geoenvironment) HydrologicalHydrological balancebalance andand waterwater demandsdemands inin thethe urbanurban areas.areas. SustainableSustainable managementmanagement techniquestechniques Water resources are the sources by which we can get the water for our different types of uses. The freshwater resource is multidimensional. It is not limited only to its physical measure (hydrological and hydrogeological), the ‘flows and stocks’, but encompasses other more qualitative, environmental and socio- economic dimensions. From: FAO From: FAO, http://www.fao.org/docrep/005/Y4473E/y4473e06.htm Renewable water resources: • the surface water • subsurface water Non-renewable water resources: • groundwater bodies (deep aquifers) that have a negligible rate of recharge on the human time-scale and thus can be considered non-renewable. From: FAO Surface water resource Surface water is the water from the lakes and reservoirs, fresh wetlands, rivers and streams Artificial riverbed through cultivated land From: USGS Natural lake From:http://www.kids Natural river bed geo.com/geography- From: USGS for-kids/0148-surface- water.php Frozen water Several schemes have been proposed to make use of icebergs as a water source, however to date this has only been done for novelty purposes. Glacier runoff is considered to be surface water. From Wikipedia From Wikipedia Surface water bodies are formed of water from direct rain, runoffs, and springs. A runoff is the part of rain water that does not infiltrate the ground or evaporate. It flows by gravity into the water body from the surrounding land. One inch of runoff rain/acre (or 2.54cm/4,047m2) is equal to 102,206.06 lit. This drainage area is known as the watershed. Watershed characteristics affect the water quality, therefore protection of these watersheds is very important. From: http://water.me.vccs.edu/courses/env110/lesson2.htm A watershed is the land area that drains water to a particular stream, river, or lake. The watershed can be identified by tracing a line along the highest elevations between two areas on a map, often a ridge. From: USGS Water From: Hawai‘i ,Association Science Glossary of Terms Water Partnerships/HAWP From:New Jersey Water Supply Authority/JWSA Groundwater is water that is found underground in the cracks and spaces in soil, sand and rock. Groundwater is stored in--and moves slowly through--layers of soil, sand and rocks called aquifers. Aquifers typically consist of gravel, sand, sandstone, or fractured rock, like limestone. These materials are permeable because they have large connected spaces that allow water to flow through. The speed at which groundwater flows depends on the size of the spaces in the soil or rock and how well the spaces are connected. The area where water fills the aquifer is called the saturated zone (or saturation zone). The top of this zone is called the water table. The water table may be located only a foot below the ground’s surface or it can sit hundreds of feet down. From: Groundwater Foundation WaterWater usesuses •Agricultural •Urban •Industrial, •Energy, •Touristic activities. From: US Global Change research program TheThe hydrologichydrologic cyclecycle Earth's water is always in movement, and the natural water cycle, also known as the hydrologic cycle, describes the continuous movement of water on, above, and below the surface of the Earth. Water is always changing states between liquid, vapor, and ice, with these processes happening in the of an eye and over millions of years. TheThe hydrologichydrologic balancebalance The water balance is an accounting of the inputs and outputs of water: Inflows – Outflows= ΔStorage From: fao.org When the INPUTS and OUTPUTS of the drainage basin system are balanced it is said to be in dynamic equilibrium. This can also be shown in a water budget, which is: Precipitation (P) – Runoff (Q) – Net Groundwater outflow – Evapotranspiration (ET) = Δstorage where the net groundwater outflow is groundwater inflows minus outflow From: Welty C, The urban water Budget, Baker R.A(ed) The water environment of Cities, Springer For urban areas, the water budget for a watershed-based control volume therefore may be altered to reflect these additional considerations and expressed as: Precipitation−Runoff−Net Groundwater Outflow+Net Potable Water Imported+Net Wastewater Imported + Net Storm water Imported−Evapotranspiration = Δstorage where net water imported is water imported minus exported by piped systems (potable water, wastewater, storm water). A developed watershed may have any combination of water, wastewater, and storm water imports and exports, which can lead to a net loss or gain to the system compared to the natural system. From: Welty C, The urban water Budget, Baker R.A(ed) The water environment of Cities, Springer WaterWater demandsdemands On a global scale and in the last decades urban development stresses water resources by increasing demand. The expanding world population and the increasing demand for consumer goods is the source of this increase. The per capita use of water varies greatly around the world. The minimum need to sustain a person’s life is about 3 liters per day; the per capita water use is much higher in developed than developing countries. For example, in Canada and the United States the annual per capita water use is 271 and 203 m3 while in Somalia and Eritrea the inhabitants use less than 2 m3 per year (Form: FAO, 2003). ¾The total water abstraction for Water demands in Europe irrigation in Europe is around 105.068 Hm3/year. ¾The total water use for urban purposes in Europe is estimated at about 53.294Hm3 /year, which amounts for 18 % of its total abstraction and 27 % of its consumptive uses. ¾The total industrial water use in Europe is 34.194 Hm3/year, which represents 18%of its water consumption. ¾Energy water it accounts for about 30 % of all the water uses in Europe. From http://geografia.fcsh.unl.pt/lucinda/Leaflets/Leaflet% 20B5%20EN.pdf and European, Environmental Agency (EEA). Europe: Water demand for all sectors (irrigation, livestock, industry & energy, households) (mm/year) (year 2005) From: European Commission, Joint Research Center Annual water availability per capita by country, 2001 (EEA, 2005) Annual freshwater availability (mm/year) (average 1990-2010) From: European Commission, Joint Research Center The warning threshold for the water exploitation index (WEI), which distinguishes a non-stressed from a stressed region, is around 20 %. Severe water stress can occur where the WEI exceeds 40 %, indicating unsustainable water use. From: EEA, 2010 WaterWater abstractionabstraction forfor publicpublic waterwater supplysupply inin EuropeEurope Water abstraction public water supply (mil. m3/year) in early 1990s and 1999- 2007 Eastern: Bulgaria, Czech Republic, Hungary, Poland, Romania, Slovakia, Slovenia, Estonia, Latvia, Western: Austria, Belgium, Denmark, Finland, Germany, Iceland , Ireland, Netherlands, Norway, Sweden, Switzerland, United Kingdom Southern: France, FYROM, From: EEA, 2010 Spain, Greece, Portugal UrbanUrban waterwater demanddemand inin MediterraneanMediterranean countriescountries Around 145 million inhabitants live in the Mediterranean coastal area, 34% of the total population of Mediterranean countries (Attané and Courbage, 2001) The rate of urbanisation in Mediterranean countries is currently 64.3% and will reach 72.4% by 2025 (Blue Plan, 2001). Mediterranean countries receive some 200 million visitors per year, mainly during the tourist season. From: Integrated Coastal Urban Water System Planning in Coastal Areas of the Mediterranean The foreseeable future: growing pressures on water resources. From: Plan Bleu ClimaticClimatic variablesvariables inin EuropeanEuropean MediterraneanMediterranean countriescountries Average annual precipitation (mm) for the period 1960 – 1990 in the European Mediterranean Countries From: Mimikou, 2005 Water recourses in Greece Present and Future. Global Nest Journal 7/3, 313-322. The map of the UNESCO' s indicator of dryness for the Mediterranean countries Values below 0.20 characterize dry regions, between 0.20 and 0.49 almost dry, between 0.50 and 0.74 almost humid, while values over 0.75 characterize humid regions. The distributions of the urban water utilization for Mediterranean Europe. From: Mimikou, 2005 Water recourses in Greece Present and Future. Global Nest Journal 7/3, 313-322. UrbanUrban waterwater demanddemand inin GreeceGreece ExistingExisting waterwater recoursesrecourses Ground The estimated amount of stored ground Water water is 10,300 hm3/year. Surface There are 765 recorded streams, 45 of Water which are perennial. There are many seasonal springs that feed into small streams. There are more than fifty lakes in Greece, three of which are trans- Water boundary.Dams of differing capacities have been storage constructed for domestic supply and features irrigation purposes and the production of hydroelectric power. From: http://environ.chemeng.ntua.gr/wsm/Newsletters/Issue2/CircumstancesInGreece.htm Precipitation (mm/yr) 1,500 to 1,900 1,200 to 1,500 900 to 1,200 600