4. Range of Circumstances in Thessaly

The fertile plain of the Thessaly Water Region covers an area of 13,377 km² that occupies the central section of mainland Greece. It is surrounded by high mountain ranges with altitudes of more than 2,000 m (Pindus, Olympus, Pelion, Othrys, Ossa and Agrapha), encircling a low plain. The River Pinios, descending from the western slopes of Pindus, separates Thessaly in two, passes through the valley of Tempi and meets the sea. Thessaly borders Macedonia to the north, Sterea Ellada to the south, Epirus to the west, and its eastern shoreline lies on the Aegean Sea. It has the highest percentage of flat land in Greece, and the mean elevation of the area is 285 m.

Among the mountains flows the Pinios River which drains into the Aegean, after passing through the Thessalic Tempi mountains. The drainage basin of Pinios River is 9,500 km² and the main tributaries are the rivers Titarisios, Enipeas, Kalentzis, Litheos and Asmaki. Thessaly Region also consists of two more water basins: the drainage basin of Lake Karla (1,050 km²), rising at the eastern side of the region, and Lake Plastira at the western side. Lake Plastira is a part of the watershed area of Achelloos River which belongs to the West Sterea Ellada Water Region.

Table 12. Surface of the drainage basins in Thessaly

Drainage Basin	Surface (km2)
Pinios River	9,500
Lake Karla	1,050
Other Basins	2,812
Total	13,362

 

The climate is Mediterranean continental. Winters are cold and summers are hot, with a large temperature difference between the two seasons. The average annual temperature is 16-17^oC. The average annual rain height is 700 mm, ranging from 400 - 600 mm at the central plains to 600-1,000 mm on the eastern part, and to over 1,200 mm on the mountains. Rain fequency is 100-130 days per year. The total precipitation is 10,426 hm³/yr and the mean annual relative humidity is 67% - 72%. Snowfall is very frequent on the mountains.

 

Figure 7. Mean monthly precipitation for the period 1955-1995 in Thessaly

Figure 8. Annual rainfall in Thessaly

Impermeable geological structures cover 39.4% of the total area; karstic aquifers cover 16.2% and permeable structures, which occur mainly on the plain, cover 44.4%. The total water availability is about 3,094 hm³, which consists of 2,558 hm³ surface water and 506 hm³ groundwater. The groundwater, which can be found in the karstic and alluvial aquifers of the region and the entire plain of mainly Neogene sediments, is replenished by Pinios River and its tributaries, and from direct rainfall infiltration.

Figure 9. Monthly average surface natural flow in the river basin of Pinios (hm³)

Figure 10. Generated discharge in Thessaly

Monitoring results show that surface water in Thessaly is generally in a good condition. The nitrite concentrations in a small number of sampling points exceed the limit values for drinking water, due to the agricultural activities in parts of the drainage basin. In some sampling points, pesticide elevated levels are shown. Although urban waste loads in the water are significant, urban wastewater treatment plants in the major cities of Thessaly safeguard the good quality of water. The treatment plants constructed in all the major cities of the area are efficient and 45% of the population of the area (80% of the urban population) were connected to the public sewer network by 1998.

Monitoring results for groundwater show that in many cases nitrates, and in some cases ammonia, exceed the critical loads for drinking water. Due to this, the Thessaly plain is designated as a vulnerable zone (Joint Ministerial Decision 19652/1906/99), in order to take the appropriate measures for the protection of the area. The elevated nitrate and ammonia levels are attributed to agriculture and animal husbandry practices.

The main anthropogenic pressures observed in Thessaly are caused by loads coming from agricultural and animal breeding activities and from the urban wastewater. Non-point source loading from agriculture and animal husbandry in the area is significant. Cultivated areas are widespread over the plain and the application of all nitrogen-containing fertilizers enriches the watercourses, causing significant pollution trends.

Pollution trends caused by industrial activities are not significant as industrial production is limited. Pollution loads from industry are most abundant in Larissa and Volos where industrial units concentrate, and are particularly visible in the coastal waters of the region.

The main pollutant loads produced in Thessaly in 1996 were:

·         BOD₅: 51,740 ton/yr

·         TSS: 66,670 ton/yr

·         Total nitrogen: 37,920 ton/yr

·         Total phosphorus: 3,750 ton/yr

Thessaly has 753,848 inhabitants. The biggest cities in the area are Larissa and Volos (total population for both cities is 300,000). The main economic activities are agriculture, industry and tourism. The region produces 6.3% of the GNP, while the per capita product is €10,950, and the mean declared income per inhabitant was €3,550 in 2000. The unemployment rate in the region is 12.2%. Total annual water consumption is 1,171 hm³, consisting of 65 hm³ for domestic use, 1,060 hm³ for agricultural use and 46 hm³ for industrial use. The consumption index is estimated at 38% and the population to water resources index is equal to 204. The exploitation index is 31%.

Irrigated agricultural land occupies 1,894 km². Water shortage problems are frequent during the irrigation period, while in the winter floods occur in large areas. The coastal zone is a favourite destination for many tourists during the summer, increasing water supply requirements during the tourist period. Areas with the highest water supply requirements are the municipalities of Larissa and Volos.

Lake Plastira, with storage capacity of 400 hm³, is regulated for hydropower production. The installed hydropower capacity is 141 MW, and the power plant produces a total of 250 GWh per year. Industrial activities are limited in the cities of Volos and Larissa, and they involve mainly food processing, textile works and iron and steel production. Thessaly has a dense network of motorways and a harbour in Volos that serves the entire area.

Water supply in the region is not regulated by a single authority. The larger cities each have their own water and wastewater services providers, but there are a number of independent local services, mostly effected through the municipalities, and thus, the pricing of water is a subject of political pressures. Public education for water conservation is limited, and cost recovery is on average poor with the exception of the larger cities.

Figure 11. Water uses in Thessaly

Figure 12. Percentage of the total water use in Thessaly in proportion with the water use in the country

Table 13. Thessaly Matrix

Natural conditions and infrastructure	Regional Context	Climate Type	Mediterranean Continental
		Aridity Index	AI>=0.65 0.2<=AI<0.5
		Permanent Population	753,848
	Water availability	Total Water Resources /Availability (hm3)	3094
		Trans-boundary Water (hm3)
	Water quality	Quality of surface water	Good
		Quality of groundwater	Average
		Quality of coastal water	Poor
	Water Supply	Percentage of supply coming from: v      Groundwater v      Surface water v      Desalination, Recycling v      Importing	15.7% 68.3% - 16.0%
		Network coverage: v      Domestic v      Irrigation v      Sewerage	45%
Economic and Social System	Water use	Water consumption by category: v      Domestic v      Tourism v      Irrigation v      Industrial and energy production	3.3%   95.8% 0.9%
		Population to resources index	204
	Water demand	Water Demand trends	Stable
		Consumption index	38%
		Exploitation index	31%
	Pricing system	Average household budget for domestic water (pa)	€ 149
		Average household budget for agricultural water
		Average household income	€ 10582
		Cost recovery	Poor
		Price elasticity	Poor
	Social capacity building	Public participation in decisions	Poor
		Public education on water conservation issues	Average
Decision Making Process	Water Resources Management	Water ownership	State
		Decision making level (municipal, regional, national) regarding: v      Water supply for each sector v      Water resources allocation for each sector	Regional National
	Water Policy	Local economy basis	Primary sector
		Development priorities	Agriculture

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