Recent Advances in Environment, Energy Systems and Naval Science

Hydrogeology and Hydrogeochemistry of Zayanderoud river and its effect on heavy metals () JAVAD TABATABAEI Department of petroleum , Meymeh branch, Islamic azad university, Meymeh, Iran [email protected]

Abstract

Zayanderud River, located in Province with a length of about 420 km flowing from west to east, is one of the most important rivers of Iran. As an important element of environmental investigation of rivers, hydrogeochemistry deals with water quality in terms of statistical parameters, determining polluted parts of aquifer, investigating pattern of changes of ground waters, hydraulic association of polluted parts of aquifer with ground waters and investigating water quality with regards to the direction of ground flows in proximity of mines, industries, etc. Therefore, hydrogeology and hydrogeochemistry of aquifers of the region are studied in brief. In terms of ground water, the region includes four studied areas, namely Lenjanat, Najafabad, Bonsaman and Borkhar. Alluvial aquifers of these areas, with various distribution and thickness, play in significant role in providing water resources for the region and have different characteristics.

Keywords: Hydrogeology, Watershed ,Zayanderoud river, Aquifer

1 Introduction can be seen. Precipitations occur in early fall through mid spring. The dry season is from mid Zayanderud Basin is located between spring to early fall. o o 31 15′N and 34 45′N . From the point of macro- scale meridian currents, the basin is located in air leakage area and is expected to show characteristics of arid areas. However, due to its wide range of altitude (from 1470 to 3,974 meters), it includes a 2 Study area full range of climates from over arid to highly humid. Western moist air and nimbus clouds which Zayanderud Basin is located in the central enter Iran rarely make it to Zayanderud River, losing plateau of Iran, comprising of a vast area. Its area is much of their humidity in western areas of Iran. about 41,550 square kilometers, 40%, 59% and 1% Therefore, a better part of the drainage comes from of which is mountainous, foothill and swamp, western mountainous areas. In general, low-pressure respectively. western nimbus systems originating from Mediterranean Sea, North Atlantic and Black Sea Zayanderud, flowing from west to east, is make the primary source of precipitation in the area. longest river of Iran’s plateau which passes through In western parts of the basin, the effect of such Isfahan City. With a length of about 420 kilometers, flows combined with mountainous ascension effect it starts in Zardkuh Mountains and dries up in gives rise to high and normal precipitations in Gavkhuni Swamp (Fig. 1). distributaries and other parts of the river, respectively. Zayanderud originally rises in Chehelgerd, 2,330 meters above sea level. The altitude of its According to above information, Zayanderud final spot in Gavkhuni Swamp is 1,690 meters. Its Basin enjoys a variety of climates and weathers. In slope is 6.6 meters per kilometer. The main source the upper parts, it is of a cold, mountainous climate of the river is located in Cheshmeh Dimeh and in lower parts a hot, arid Mediterranean climate

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( 32o 30′N 50o 30′E ). The river mouth is located in change of ground water level balance for 1972–2007 is shown in Tab. 4. Gavkhuni (32o 20′N 52o 45′E ). Tab. 5 provides quantitative condition of In general, the basin may be divided into two ground waters of the plains in 2006–2007 year. sections, namely pre-Zayanderud Dam and post- Zayanderud Dam. In addition, in order to investigate quality of ground waters in the plains, average qualitative parameters are provided in Tab. 6.

4 Hydrometric Networks

Hydrometric networks are usually installed to measure discharge and water quality of the river. Number and location of hydrometric stations depend on the importance and significance of the river, easy access to the river, being close to a city and economic issues. Since hydrometric stations are stationary, they are considered suitable options for Fig. 1. GIS map of Zayanderoud watershed and its sampling procedures which serve environmental distributaries investigations.

3 Hydrogeology and Hydrogeochemistry 5 Discharge Regime

Hydrogeology and Hydrogeochemistry of Discharge is the volume rate of water flow aquifers of the region are studied in brief. In terms which is transported through a given cross-section. of ground water, the region includes four studied It is usually expressed in cubic meters per second. In areas, namely Lenjanat, Najafabad, Bonsaman and other words, discharge is equal to water velocity Borkhar (Tab. 1). multiplied by cross-sectional area. Discharge varies with year, usually having its highest value in spring Alluvial aquifers of these areas, with various due to the increased snowmelt, higher precipitation distribution and thickness, play in significant role in and floods. On the other hand, discharge is lowest in providing water resources for the region and have warm months. Discharge plays an important role in different characteristics. Their characteristics and hydrologic investigations, especially those aimed at properties are tabulated in Tab. 2. evaluating surface erosion.

Tab. 3 provides a summary of observation Discharge affects water pollution as well. wells and geophysical studies conducted on aquifers With a constant rate of pollutants getting into the of these four areas. river, the more the discharge, the less will be pollutants’ concentration in water. Evaluating and Based on the data, water level balance of estimating water pollution is only possible if the piezometers dug in plains, and water level balance discharge and characteristics of both wastewater and of aquifers and their changes and volumes are river water is accurately determined. investigated . Highest water discharge of Zayanderud River These investigations reveal that in plains next belongs to May, and the lowest one belongs to the to Zayanderud River, ground water generally flows period from mid January to mid March. More from mountainous areas towards the river. Pattern of

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decrease of discharge in winter is due to snow-rain either physical adsorption or a result of chemical regime of the river (i.e. snowmelt provides for a exchanges. During absorption process, several better part of river’s water) and Zayanderud Dam phenomena including chemical sedimentation, operation protocol. The dam is closed down in physical absorption, reaction with absorbing winter to gather enough water for spring and particles, etc. can occur summer. In general, pollutant concentration increases as discharge decreases . In other words, higher discharge helps reduce salinity and Ec and decrease adsorption of pollutants by precipitating particles. These effects consequently decrease References pollutants concentration. When discharge decreases, all processes go in opposite direction. [1] Aghanabati S. Geology of Iran. Geological and explorations survey of Iran Publ., 2003. Tab. 7 provides average qualitative [2] Ferguson J.E. The heavy elements: parameters of Zayanderud River, measured in chemistry, environmental impact and health several hydrometric stations. effects. Oxford: Pergamon Press, 1990, 614 In Zayanderud River, pH varies from 7.3 to p. 8.68. This range is considered a normal range of [3] Forstner U. Traceability of sediment variation for rivers. The temperature easured in analysis. Trends in Analytical Chemistry, sampling stations was between 10.9 and 18.7 2004, v. 23, p. 217–236. degrees Celsius. [4] Jamab Conductor Engineers, Climate and Water resources condition in Gavkhoni watershed, now and future, national management office (water affairs), 1978, 229 p. [5] Moussavi-Harami R., Mahboubi A., 6 Conclusion Khanehbad M. Analysis of controls on downstream fining along three gravel-bed Chemical analysis of water solutes helps rivers in the Band-e-Golestan drainage basin determine river water quality. Concentration of NE Iran. Geomorphology, 2004, v. 61, p. solutes and water salinity depend on several factors 143–153. including geological structure of the basin, climate, [6] Singel F. Environmental geochemistry of discharge regime, exchange between surface and potentially toxic metals. Berline: Springer- ground water, water applications and finally quality Verlag, 2002, and quantity of waters discharged into river through 214 p. natural or manmade drainage systems. Since solutes [7] The sednet strategy paper. Demand driven. concentration can affect absorption and European sediment research network – transportation of heavy metals, determining water proposal no. EVK-2001-00058 to EU key quality is of great importance in environmental action1 “Sustainable management and studies . quality of water”, 1.4.1 “Abatetment of water pollution from contaminated land, Through the course of the river, heavy metal landfills and sediments ”(1\2002-12\2004). ions can be absorbed by suspended particles due to draft, June, 2003 collision with them. The absorption process can be

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Table 1. Four studied area in the region.

Height Area(km2)

mean C oderegion Name Total Mountain Plain (m)

1900 817 680 137 4210 Bon – saman

1600 3381 1674 1707 4209 Lenjanat

1600 1712 647 1065 4206 Najaf abad Esfahan – 1585 3385 926 2459 4202 borkhar

Table 2. Characterization of alluvium and aquifer in plains of the region.

transmisivity Alluvium Mean of Water table height (m) thickness (m) storage (m2/day) Code region Name coefficient Mean Max Mean Min Max Mean Max

5 - - 21 2 60 50 100 4210 B0n – saman

6 5 2445 21 2 70 80 180 4209 Lenjanat

5 20 4000 46 4 71 128 300 4206 Esfahan – borkhar

6 11 2601 19 1 66 60 112 4202 Najaf abad

Table 3. Characterization of well exploration and geophysical observation of plains in the region.

Geophysic Alluvial exploration depth

Piezometer Exploration well Code region Name Sondage rate Depth Depth Number Number total total

209 167 3 362 4 4209 Lenjanat

309 130 2 1510 13 4206 Borkhar

136 479 8 776 12 4202 NaJaf abad

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Table 4. Water table changes and aquifer volumes in the region.

Yearly decrease Cumulative Yearly mean mean Aquifer decrease of decrease v olume volume Statistical Plain aquifer aquifer mean Aquifer type Code of aquifer limit name (Km2) )MCM( (m) (MCM)

-0.36 -0.03 -0.001 1200 Non-confined 61-86 4209 Lenjanat

Confined, Non- -2532 -101.3 -0.99 1700 61-86 4206 Borkhar confined

-33 -1.32 -0.07 1000 Non-confined 61-86 4202 NaJafabad

Table 5. Ground waters resources quantitative in the plains of region.

(MCM)consumptions well region (karez) spring discharge Name deep subdeep total total Drin- Agri- Industry dis- dis- dis- dis- kage culture (MCM) number charge number charge number charge number charge (MCM) (MCM) (MCM) (MCM)

Bon – 2 77.6 79.6 213 55.2 396 13.8 28 9.6 16 1.0 saman

19.6 2.3 392 477 369 201 169 48.3 559 167.1 758 60.6 Lenjanat

51.3 5.1 791.7 853 73 21.8 1 1 2107 323.3 8449 506.9 Najafabad

Esfahan – 12 9.3 457.3 479.1 20 2.3 4 0.2 1217 390.3 503 86.4 borkhar

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Table 6. Quality parameters mean of ground waters in the region.

Aquifer quality parameters mean region Name Na So4 Mg CL EC (meq/l) (meq/l) (meq/l) (meq/l) (mc/cm)

- - - - 454 Bon – saman

9 7 9 8.4 1883 Lenjanat

4.1 2.9 4.1 4.4 1833 Najafabad

Esfahan – borkhar 20.8 18.1 20.8 9.7 5164

Table 7. Average qualitative parameters of Zayanderoud river.

Mean of river quality parameters Station Anions and cations (meq/l) TDS TH River name name PH EC Na Mg Ca So4 Cl HCo3 (mg/l) (mg/l)

.14 .57 1.82 .19 .18 2.1 -7.98 238.13 154.75 119.2 chehelgerd kohrang

Ghale .42 .77 2.46 .43 .39 2.84 7.72 323 210 161 zayanderoud shahrokh

.49 .78 2.25 .48 .39 2.66 7.81 315 205 151 Zaman khan zayanderoud

1.5 1.27 2.9 1.18 1.1 3.35 7.73 513 332 208 chamaseman zayanderoud

babamah- 2.29 1.58 3.5 1.86 1.77 3.67 7.59 568 270 254 zayanderoud mod

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