Hydrogeochemistry of seasonal variation of Urmia Salt Lake, Iran

Abstract

Urmia Lake has been designated as an international park by the United Nations. The lake occupies a 5700 km2 depression in northwestern Iran. Thirteen permanent rivers flow into the lake. Water level in the lake has been decreased 3.5 m in the last decade due to a shortage of precipitation and progressively dry climate. Geologically the lake basin is considered to be a graben of tectonic origin. Na, K, Ca, Li and Mg are the main cations with Cl, SO4, and HCO3 as the main anions. F & Br are the other main elements in the lake. A causeway crossing the lake is under construction, which may affect the lake's annual geochemistry. The main object of this project is mainly to consider the potential of K-mineral production along with ongoing salt production. Seven hundred and four samples were taken and partially analyzed for the main cations and anions. Surface water (0.5 m. depth) was analyzed for Na, K, Mg, Ca, Br and Li, and averaged 87.118 g/lit, 1.48 g/lit, 4.82 g/lit, 4.54 g/lit, 1.19 ppm and 12.7 ppm respectively for the western half of the lake. Sodium ranged between 84 to 91.2 g/lit, and showed higher concentrations in the south than in the north. This unexpected result may be caused by shallower depth in the south and a higher net evaporation effect. Calcium ranged between 4.2 to 5 g/lit, apparently slightly higher in the north. K is higher in the south, possibly due to rivers entering from south that may carry slightly higher K in solution. In the middle-range samples (0.5-5 m.), K averaged 1.43 g/lit and ranged from 1.40 to 1.46 g/lit. At this intermediate depth the distribution of K is clearly higher to the south of the causeway that is currently under construction. It is not clear whether this increase is the effect of the causeway or the effect of the salty Aji-Chay River to the east, and the Khoy salt domes to the north of the lake. At depth (5 m-10 m), K averaged 1.48 g/lit and ranged from 1.4 to 1.49 g/lit, differing only in the second decimal from the average of the middle and surface samples. Ignoring the small difference between the averages of the three sample depths, the distribution of K is highly homogeneous in the lake water due to the mixing process. Therefore causeway construction has not yet strongly affected K distribution, or it may be at the starting point. Magnesium concentration ranged from 4.6 to 5-g/lit, and was elevated in the south. This differs somewhat compared to calcium. Lithium, with an average of 12-13 ppm, is slightly higher in the south, and has not shown any significant variation in all three seasons. Iodine was below the detection limit in the lake. Urmia Lake, geochemically, is highly uniform both to the south and north of the causeway, in both the surface and deep brines. K and Mg, which average 1.48 and 6.6 g/lit in order, could be elements worth production in addition to the NaCl currently being produced from the lake. Br, F, Li and B in the limit of <50 ppm don't look to be in the economical range.

Hydroclimatic variations over the last two glacial/interglacial cycles at Lake Urmia, Iran

“…Low relief along the eastern edge of the basin results in significant seasonal and interannual variations in lake size and depth (Kelts and Shahrabi 1986). The current maximum depth is 16 m (Sharifi 2002), although strandlines, perched 5 m above current lake level, provide evidence of earlier high stands (Alipour 2006). The deepest section is located slightly north of the narrow neck, west of the Shahi Island/Peninsula (Fig.…”

“…Salinity varies seasonally, with maximum concentrations in fall (Alipour 2006). Rivers entering the lake are fresh; however, springs tend to have high solutes (Kelts and Shahrabi 1986).…”

“…The NW-SE trending basin is large (*5,000-5,700 km 2 ) and shallow (Alipour 2006). Low relief along the eastern edge of the basin results in significant seasonal and interannual variations in lake size and depth (Kelts and Shahrabi 1986).…”

Effective watershed management; Case study of Urmia Lake, Iran

“…The lake is also one of the most important and valuable aquatic ecosystems in the country. Some 1500 species of vascular plants, including unique Artemia The lake basin, as a unique socio-ecological region, is facing extreme water shortages due to poor water governance and climate change (Alipour 2006, Zarghami et al 2009). Because of the intense agricultural development and rapid urbanization, the groundwater level in some parts of basin has decreased by up to 16 m (Fig.…”

A Spaceborne Multisensory, Multitemporal Approach to Monitor Water Level and Storage Variations of Lakes

“…The main water of the lake is supplied from 21 seasonal or permanent (the main inputs are Zarrine-Rud, Aji Chay, Baran duz, and Godard), and 39 periodic rivers and springs [57,58]. The watershed area covered about 52,000 km 2 which is 3% of Iran's land [59]. The basin with 6.4 million inhabitants is important in terms of housing, industrial and agricultural activities for the East Azerbaijan Province in Iran [56,60].…”