Eivissa is a very popular tourist destination， especially due to its legendary riotous nightlife (mainly in Ibiza Town， the island，s capital on the eastern shore). The most famous clubs include Privilege (the world，s largest club which holds the weekly event known worldwide as Manumission on Monday nights)， Es Paradis (famous for its water parties)， Amnesia (famous for its foam parties and what goes on there)， Space (opens at around 8a.m.) and Pacha. Ibiza is also famous for Café del Mar， a chill spot in Sant Antoni where many people watch the sunset every night.
If you leave the beaches behind you to explore the island，s interior， you will find a pure and simple Mediterranean culture， and remains of populations which inhabited Ibiza thousands of years ago.
Ebro River
埃布罗河
埃布罗河位于欧洲伊比利亚半岛北部，是西班牙最长、流量最大和流域面积最广的河流。源出坎塔布连山脉雷诺萨附近。流向东南，经巴塞罗那和巴伦西亚之间河口三角洲注入地中海。长927千米，流域面积8.3万平方千米。仅河口与托尔托萨之间流段可通小船。虽有200多条支流，但土地干旱、贫瘠，人口稀少。最大支流已被开发用于发电和灌溉。流域盆地东南部及其下游地区褐煤蕴藏量丰富。
The Ebro river is the most important river in Spain， with 928 km long and 85，550 km2 of drainage basindrainage basin n.（美）流域，流域盆地. However， the mean annual flow has decreased approximately 29% during this century due to many causes： the construction of dams， the increasing demanding irrigationirrigation n.灌溉， 冲洗 and the evaporation (higher than the rainfall， due to low rainfall， high sunshine and strong and dry winds) from reservoirs in the river basins. This situation has a direct impact on the deltaicdeltaic 三角洲的 三角形的 system at the mouth of the river because its hydrologicalhydrological adj.水文学的 dynamicsdynamics n.动力学 is mainly controlled by the river discharge and the introduction of the salt wedge is favoured by the low tidal range (20 cm) and the diminution on the river discharge. The mean annual river flow is， approximately the critical flow which determines the formation and the breakup of the salt wedge. Thus， when the river dischargedischarge vt.卸下， 放出， 清偿(债务)， 履行(义务)， 解雇， 开(炮)， 放(枪)， 射(箭) vi.卸货， 流注 n.卸货， 流出， 放电 is between 300 and 400 m3， the salt wedge can occupy the last 5 km of the estuary， but when the discharge is between 100 and 300 m3， the salt wedge can advance up to 18 km from the mouth， near the Gracia Island. For less than 100 m3， the salt wedge quickly advances to its maximum extent， reaching 32 km from the mouth. In addition to decreased mean annual flow， the increased river regulation in the Ebro basin has produced daily and seasonalseasonal adj.季节的， 季节性的， 周期性的 changes in the flow pattern.
Regarding to the sediment load， there are no historical data on sediment transport. Several authors have estimated the sediment transport values at the beginning of the present century， concluding that the sediment load has been reduced more than 99% during this century. The drastic reduction in sediment transport implies a sediment deficit in the Delta， which is causing the erosionerosion n.腐蚀， 侵蚀 of the coastline. This erosion together with the sinking of the Delta produced by soil compactation and tectonic subsidence cannot be balanced by the depositiondeposition n.沉积作用， 沉积物， 革职， 废王位， 免职 of fluvial sediments， nearly all of them retained in the dams.
Regarding the nutrients， the Ebro river increased the eutrophicationeutrophication n.超营养作用 of its waters during last decades， mainly due to the human activities， like domestic consumption， industries， agriculture and refrigeration of nuclear power stations. These water uses have caused the rise of nutrients and organic matterorganic matter 有机物 in the river estuary. According to the Ebro Hydrographic confederation， the averaged ortophosphates concentrationsconcentration n.集中， 集合， 专心， 浓缩， 浓度 increased from 0.2 mg/l in the 60，s to 0.9 mg/l by the end of 80，s， while the nitrates grew from 3 mg/l to 9 mg/l in the same period.
The Ebro river is the largest fluvial system in Spain. Its drainage basin covers an area of 85，001 km2 with 3.4 km in relief. Most of the water inflow to the Ebro river is supplied by the left margin tributaries， whose headwatersheadwaters n.源头， 上游 are located in the Pyrenees. The Gállego and Huerva tributaries flow in the Ebro river at Zaragoza city. Up stream of the Gállego and Huerva confluences， the Ebro has a mean discharge of 266.76 m3/s (Ollero， 1996)， corresponding to a catchment area of 40，434 km2 up stream of the gauging station. The gaugingstation of the Gállego river in Zaragoza records 38.82 m3/s in mean discharge (upstream catchment areacatchment area n.排水区， 下游区 of 4，009 km2). The Huerva river has an average discharge of 2.12 m3/s (upstream catchment area of 1020 km2). In Sástago， around 50 km downstream of Zaragoza the Ebro river reaches 276.83 m3/s in mean discharge (upstream catchment area 48，974 km2， thus a reduced specific flow).
The annual flow regime of the Ebro river in the study area depends on the runoff derived primarily from rainfallrainfall n.降雨， 降雨量 and secondly from snow melt. The highest mean monthly discharge occurs in February (461.71 m3/s)， and the lowest in August (59.37 m3/s) (Ollero， 1996) (Figure 3.30). However， floods are most frequent in the months of January and December. The maximum peak flood discharge recorded at Zaragoza gaugingstation during the period 1913～1985 reached 4，130 m3/s (2nd， January 1961). In the time interval 1959～1985， the maximum instantaneous dischargeinstantaneous discharge 瞬时放电 has exceeded 3，000 m3/s in two flood events.
