Boctor of $I)Uo£;Opt)P in GEOLOGY
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AQUIFER SYSTEM AND GROUNDWATER RESOURCE EVALUATION IN PARTS OF HINDON-YAMUNA WATERSHED IN PARTS OF WESTERN UTTAR PRADESH ABSTRACT OF THE THESIS SUBMITTED FOR THE AWARD OF THE DEGREE OF Boctor of $I)Uo£;opt)P IN GEOLOGY BY FAKHRE ALAM DEPARTIVIEWT OF GEOLOGY AUGARH A/IUSLIM UWrVERSITY AUGARH (liMOIA) 2010 ABSTRACT The study area, a part of the vast central Ganga Plain, is delimited in the east and in the west by Hindon and Yamuna rivers, respectively. It lies between latitude 28^47^ and 29*^18'N and longitude ll%il>{)" and lfl>{^ E and covers an area of about 1,345 km^ The area is well endowed with the groundwater resources but over-exploitation has created adverse impact on the groundwater regime. It is one of the densely cultivated tracts and serves as leading producer of crops especially sugarcane, paddy and wheat. The high stress on groundwater for irrigation due to pumpage of large quantities of groundwater for irrigation has threatens the sustainai^ility of agriculture development. :/• ''" ;"',• Groundwater development has. a^eady reached to a critical stage in some part of the study area and therefore, the area wa^ trndgrtaksbrfor present work. The present research has been focused on aquifer system and its quantitative and qualitative evaluation and management of groundwater resources in multilayered aquifer. For the said purposes detailed hydrogeological, hydrogeochemical field and laboratory investigations were carried out to generate data base. The average annual rainfall in the area is about 500 mm and a decline by about 70 mm is indicated during the last two decade, which may possibly be a manifestation of climatic changes. Digital Elevation Model (DEM) exhibits a gentle slope towards south and ground elevation ranges from 192 to 256 m above mean sea level. Land use and land cover patterns show conspicuous changes in response to demographic factors and industrialization in the period from 1992 to 2008. Population explosion, increased irrigation requirements and industrialization have exerted tremendous pressure on groundwater resources which take care of 96.18 % of the total water requirements in the area. Geologically, the area is characterized by about 1000 m thick Quaternary alluvium resting over the rocks of Delhi Super Group. The bed rock has not been encountered in wells as deep as 600 m. Three major groups of aquifers have been identified separated by relatively less permeable horizons. Aquifers 1 and II have better potential and utility than aquifer III which gives lower yields due to preponderance of 1 finer elastics. Even deeper, aquifer IV has been intersected in the area to the east of river Hindon, which may or may not extend to the study area. Aquifer I, to which the present study is practically confined, continues to a depth of 126 m bgl with a persistent clay layer on top and intervened by local clay lenses. Pre-monsoon seasons 2006 and 2007 have depth to water level varying between 8.95 and 29.16 m. In corresponding post-monsoon periods, it is 8.62 to 28.96m. Deeper water table occurs in the northeastern part of the area, whereas it is shallower along river Yamuna and Eastern Yamuna Canal (EYC). A general rise of water table is indicated in post-monsoon period of 2006 but due to weak monsoon changes observed are trivial in post-monsoon period of 2007. Water level fluctuations in 2006 were on the positive side to as much as 1 m. High fluctuations are associated with deeper water table conditions in northeastern and central parts and shallow water table conditions in the southwestern part. In 2007, on the other hand, 73% of the wells show negative fluctuation due to very poor monsoonal recharge and simultaneous higher rate of withdrawal due to enhanced requirement for irrigation purposes. Historical water level data on 14 permanent monitoring wells show a declining trend. Average annual decline in water level on eastern and western sides of EYC are 0.64 and 0.80 m, respectively. The flow of groundwater is, in general, towards east on the left bank of EYC and towards west on its right bank. Local variations occur on the left bank, where some flow in the opposite direction defines a major trough along river Hindon, obviously related to over-exploitation. Seepages from canal are manifested as groundwater mounds. It needs to be mentioned here that there are no chemical expressions of inferred groundwater troughs and mounds and these are indistinguishable on any chemical map. The isopermeability map shows that the bulk of the area is covered by permeability zone of 30 to 40 m/day and good correlation has been observed between Logan's estimated K and pumping test K values. The pumping tests give aquifer parameters like T and K at 887 to 2772 m^/day and 12.7 to 40.10 m/day, respectively. These values of K, however, are an order of magnitude higher than lab-determined K values. The velocity of the lateral movement of groundwater comes to 9.2 to 11.6 m/day or about 10 m/day. This implies thai groundwater would cover a distance of 1 km in 3 to 4 months time. The groundwater budget estimation for the period from 1^' June 2005 to 31^' May 2008 indicates that total recharge during three successive years was 535, 489 and 467 MCM, respectively. Corresponding total discharge estimates are 688, 704 and 705 MCM. Thus deficit balance of 153, 215 and 237 MCM, respectively, is worked out. The stage of groundwater development for the three years period is worked out at 128%, 144% and 150%, respectively and the entire study area comes under over-exploited category. An alarming stage has already arrived that is likely to deteriorate further in the coming years. In the absence of any immediate remedial measures the shallow aquifer may cease to yield in the next decade. There is chemical evidence indicating that the bulk of about 150 MCM (per annum) water entering the groundwater system as canal seepage, affects the western part more than the eastern. Mass balance equation shows that this mixing of groundwater and canal seepage has to be in a ratio of 0.95:0.05. MODFLOW 4.1 has been applied to a three layered model conceived for the puipose. November 2005 situation is taken as the initial condition for steady state model calibration, which shows good agreement between observed and simulated heads with a Root Mean Square (RMS) error of 1.471 m. Two prediction scenarios were attempted. In scenario 1 (constant recharge and increase in current withdrawal rate), the minimum drawdown of < 2 m was observed along river Yamuna and in upper and lower reaches of river Hindon. A maximum drawdown of > 6 m was observed in northeastern, northwestern and southeastern part of the study area at locations, rendering 13 observation wells becoming dry by 2018. In scenario 2, the combined effect of increasing abstraction rate by 20%) and reducing recharge by 20% was examined. The maximum drawdown of > 7 m is observed in northeastern, southwestern and southeastern parts. In this scenario number of dry cells increased in comparison to scenario 1. The minimum drawdown of <2 m is observed in the vicinity of upper and lower reaches of ri\'er Yamuna and Hindon. Groundwater in the study area has 'Low to Mediun-i (Class I)' electrical conductivity and bulk of the samples are moderately hard to hard. TDS values are averaging >1000 mg/1 for both the sets of samples, post-monsoon value being higher. There is a clear tendency of redistribution of TDS and higher values concentrate in the northern half of the area in pre-monsoon period of 2006. Anomalously high TDS values, as high as > 1800 mg/1 and averaging > 1000 mg/1, suggest that the role of water - rock interaction as a mechanism for the acquisition of solute is not substantial and processes, such as, anthropogenic activities, dissolution of some naturally occurring materials or mixing with deep-seated ascending brines may have a more dominant role to play. A general decrease in average TDS during a period of about 6 months from November, 2005 to June, 2006. when there were hardly any rains, could imply dilution of groundwater due to interaction with surface water bodies or shallow groundwater. A mass balance equation suggests such dilution to the extent of 25%. Such a process of simple dilution is not tenable in the light of the chemical data available and based on ground realities. Therefore, a combination of factors, such as, precipitation/dissolution, irrigation, cation exchange, and influences of climatic and various anthropogenic factors, rather than dilution alone, explain the observed chemical changes in a more lucid way. River Krishni and the upstream sample from river Hindon show conspicuous effect of pollution implying that the pollution could be transmitted to groundwater level when these rivers exhibh influent behavior. Other river samples are with TDS of < 500 mg/1. This implies that in influent part of their courses rivers would tend to dilute the groundwater and their effluent behavior would be reflected in higher TDS content in their discharge. On Piper's Trilinear Plot, overwhelming abundance of alkalis over Ca and Mg and presence of all the anions is indicated. Bicarbonate, though, is more dominant. On L- L Diagram 3 chemical types of groundwater, 'mixed", 'mixed bicarbonate' and 'alkali bicarbonate' types, are identified. The two "bicarbonate types" tend to merge in to one cluster in post-monsoon 2006 samples. Chemical signatures of meteoric origin of groundwater are completely obliterated as a result of the acquisition of solutes in varying but substantial concentrations through various natural and anthropogenic processes.