Intermediate report. Letter of agreement FAO - GCB/RAB/013/ITA

Transcription

1 Treated waste water for sustainable production of valuable biomass, soil and water quality improvement and combating desertification in Algeria and Tunisia Letter of agreement FAO - GCB/RAB/013/ITA Intermediate report November 2012

2 ANNEX 3 - SHORT DESCRIPTION OF THE PROJECT AREA: OUECHATA (TUNISIA) Site The city of Ouechtata belongs to the governorate of Beja and the delegation of Nefza. Close to the municipality of Nefza, the oasis of Ouechtata is located in the area of the dam of Sidi el Barrak. The Sidi El Barrak dam is operative from 1999 and the water regime has been heavily modified in the area. The dam is located on the river Zouaâra, 2 km from the coast and it blocks about 265 million cubic meters of water. The basin is alimented by the valley of Wadi Ez Zouaâra and at the lower portions of the valleys of Wadi Melah, Maaden and Bouzenna. The area of the reservoir reached 2734 hectares and the normal level of the water is about 27 meters from the sea level. The Sidi El Barrak dam must serve three purposes. In drinking water: it must ensure the mobilization of 190 m3 per year. In agriculture: it helps improve the quality of water intended for irrigation in the Cap Bon region and the creation of approximately 5500 ha of irrigated land in the area Sejnan, Nefza. In ecological terms: it guarantees the creation of an essential part of the overall strategy of maintaining the balance of the ecosystem of the Ichkeul Park. Geography Soil and geology The river valley of the wadi Zouarâa interrupts the mountain and flows into the sea in the Zouarâa beach; a well-developed beach characterized by coastline stability and well developed coastal dunes. It measures several tens to hundreds of meters in width, and is limited by back dunes extending over hundred km² in the region of Ouechtata. Surface water and groundwater The aquifer of Nefza, is in the dunes and covers an area of some 40 km 2. It is in contact with the sea over a length of 10 km. The groundwater is of excellent quality (salinity less than 0.5 g/l). The rate of abstraction determines the intrusion of seawater. The interface can be in a permanent position at 170 m inland from the coastline with an outflow of groundwater in seaward direction of 0.75 x 10-4 m 3 /sec/m. In particular, it appeared than an abstraction rate of 90 % of the natural outflow during 20 years brings about a displacement of the interface in an inland direction of 75 to 175 m.

3 Climate Rain J F M A M J J A S O N D Monthly avg [mm / month] Annual avg [mm / year 625 Temperature Monthly avg [ C] Monthly min [ C] Monthly max [ C] Annual avg [ C] 20.7 Waste water characterization: flow and quality A preliminary set of data about the waste water, are summarised in the following table. population habitants 4'350 drink water consumption litres / day 150 collected wastewater * litres / day 120 annual wastewater volume m 3 / year 190'530 * considering a 30 l of losses. NOTE : right now the majority of the population is no connected to the sewerage system. Additional information to be collected: biological conditions, wetland microbial and plant inventory, wastewater characterization: flow and quality, treatment goals and regulatory constraints.

4 ANNEX 4 - SHORT DESCRIPTION OF THE PROJECT AREA: HAFFUZ (TUNISIA) Site The experimental site is located in the city of Haffuz, near the sewage treatment plant of the city (35 38' 03.56" N 9 42' 27.68" E). It is located at an altitude of about 300 m above sea level. Haffuz is situated in central Tunisia, in the governorate of Kairouan. Geography Soil and geology Overlapping the Atlas area and the old continent, Tunisia shows a folded structure in the north and a monocline structure in the south. The soils are sedimentary except in the Galite where they are eruptive. Tunisia is located in a geological region mainly limestone. The mountainous North is characterized by karst morphology. The experimental area is characterized by a diversity of soil that can be summarized in the following main types of soils: gypsum accumulation, soil crusting or gypsum crust, calcomagnesimorphes sols, soil intake modal and sand. Surface water and groundwater The natural hydrography reflects the rainfall situation of Tunisia: the northern wedis are generally well supplied, especially in winter. Those in the south are usually dry but can become formidable torrents, during their episodic courses lose themselves in the interior basins; the most important is the Chott El Jerid. Meanwhile the rivers of the central region flow down from the Atlas to the south where they evaporate in salt marshes. Water resources in Tunisia are in limited quantities and with uneven spatial distribution. The last resource evaluation reported 4503 million m 3, of which 2700 m 3 are surface waters, and 1803 m 3 are groundwater. Compared to other Maghreb countries, these resources are low, due to the small size of watersheds and countries, and limited rainfall. The country has a poorly developed hydrographic network. Megerda River, 365 km long, was born in Algeria but runs for ¾ of his career in Tunisian territory before flowing north of Tunis. In the fertile valley of Megerda focus agricultural activities in the country. Unique lake basin sweet feature is the lake of Bizerte, while in the southern desert are the two salt lakes of Chott el-jerid (whose eastern

5 part is sometimes considered a separate basin and also called Chott el-fejaj) and Chott El Gharsa, whose western part is in the Algerian territory, and their basins are dry for part of the year or at the muddy and covered with salt, so that more lakes real the correct term would sabkha or salt deserts. Surface water resources are mostly concentrated in the northern part of the country. The North comprises the main oueds of Tunisia, which receives the greatest rainfall amounts (more than 400 mm / year), includes the basins of the North-East (Cap-Bon, and Miliane Ichkeul) and the North West (Medjerda and far North). As the center (between 400 mm and 200 mm / year) and South (less than 200 mm, often at 100 mm), they are characterized by aridity and endoreism. On the other hand most of the groundwater resources come from the aquifer of the south, where the most important are the fossil groundwater Intercalaire Continental and Continental Terminal. Climate Generally, central Tunisia is characterized by a semi-arid, continental shade climate, with high temperatures and modest rainfall, among 200 and 400 mm/yr, in particular Haffouz s area show the following characteristics: Rain J F M A M J J A S O N D Monthly avg [mm / month] Annual avg [mm / year 293 Temperature Monthly avg [ C] Annual min [ C] 2.5 Annual max [ C] 44.0 Annual avg [ C] 20.3 Vegetation Tunisian vegetation is highly diversified to large sets of topographic and climatic conditions ranging from North to South. Once again, the relief and rainfall act as determinants of the distribution of vegetation on the whole territory. However, the presence of vegetation in Tunisia depends essentially on its resistance and adaptation to drought, especially during the summer when warm southerly winds present a serious threat. The central Tunisia is characterized by Steppes that separate the relief of North and the desert of South. The vegetation zone corresponding to the steppes of Alpha and olives characterizes the coastal plain and the interior. The steppe is covered with large grassy alpha field, sparte and sagebrush.