Impact Study of a check dam on Ground Water Recharge

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1 Impact Study of a check dam on Ground Water Recharge 1 P.Arun Raja, C. Dinesh, B.Jagadeesan 1,, UG Student, Department of Civil Engineering, Mamallan Institute of Technology, Kanchipuram, INDIA Abstract: The main source of water is rainfall which runs through the river as surface water source. Those rivers are connected to the oceans, partial amount of water in the river collected in ocean and get wasted. To reduce that, we need to stagnate the running water in the river. Checkdams are used for that purpose. The stagnated water can be used during the non monsoon periods. Now as we all know the use of checkdam, in our project we analysis the effect of checkdam on ground water recharge. We have chosen a checkdam constructed in Tiruvannamalai district, Melmuthanur village. Rainfall data and water level in well data are collected from near by rain gauge station and well data station for the analysis of the impact of checkdam on ground water recharge. construction of Checkdam. Following three objectives have been formulated through which the Checkdam are evaluated, 1. To evaluate the flooding characteristics of urban river.. To determine the effectiveness of check dam using the flooding characteristics and groundwater characteristics of urban river. II.STUDY The Checkdam is constructed at the downstream of Tiruvannamalai to arrest floodwater from Pambanar Sub-Basin flowing into the river during monsoons. The check dam is constructed at Melmuthanurvillage river to reap benefits in the form of groundwater recharge. Latitude N, Longitude E. We used Arc-gis software to find the catchment area of the checkdam and HEC-HMS software to find the effective runoff. Water table fluctuation method is used to find the effectiveness of checkdam on ground water recharge. I. IRODUCTION Checkdam is constructed mainly to provide direct irrigation when rain fails and for recharging the surrounding wells through percolation of water. The Checkdams are used in minimising the velocity of floods and to conserve soil and water. The need for study is that how far it is efficiently performing in terms of improving the groundwater quantity and is there any change in life style of people living there before and after 7

2 III.METHODOLOGY rainfall), modeling direct runoff, flood routing, calibration of the model, and model validation Volume discharged ( ) Sub basin1 Subbasin m /s TIM E OF PEA K 6Jul 010, 6Jul 010, 6Jul 010, Volume discharged (011-01) IV.TERRAIN PREPROCESSING Terrain pre-processing marks the first step in developing an HEC-Geo HMS project. In this step, a terrain model is used as an input to derive eight additional datasets that collectively describe the drainage pattern of the watershed and allows for stream and sub basin delineation. The first five datasets are grid layers that represent the flow direction, flow accumulation, stream network, stream segmentation, and watershed delineation Model setup and Simulation In this study, the distributed modeling approach is adopted in flood hydrograph computation. The methodology involved in computing the flood hydrograph of the basin at the outlet can be broadly divided into five stages, including computing runoff volume (excess 1 m /s TIME OF 0Dec 011, 0Dec 011, 0Dec 011, Volume discharged (01-MAY 01) m /s TIME OF 01, 01, 01, V.GRAPH (obtained from HEC-HMS) 8

3 A hydrograph is a graph showing discharge (i.e., Stream flow at the concentration point) verses time. At the beginning, there is only base flow (i.e., the ground water contribution to the stream) gradually depleting in the exponential form. After the strom commences, the initial losses like interception and infiltration are met and then the surface flow begins. The hydrograph gradually rises and reaches its peak value after a lag time. The below hydrographs are obtained from the HEC-HMS software. Hydrograph for sub-basin 1 (01) VI. WATER TABLE FLUCTUATION METHOD The water level fluctuation method is applied for the monsoon season to estimate the recharge. The ground water balance equation for the monsoon season in non-command areas is given by (GEC, 1997). Hydrograph for sub-basin 1 (010) Where, h = Ground water level difference in monsoon (m) S y = Specific yield (.65) For clayey soil it is 5 to 1% A= Area (m ) YEAR RUNOFF Mm HEIGHT m Hydrograph for sub-basin 1 (011) MAY VII. GRAPHICAL ANALYSIS The graphs are plotted using the observed rainfall data and well data. The Precipitation is 9

4 maximum during the North-East monsoon. Observing the well data graph, the water recharge has increased after the construction of the check dam in year 011. The rain fall in year 01 is quite less than the average and the water recharge for the respective year is more than the average recharge. This graphical representation itself proves that the check dam constructed in melmuthanur village is effective. velocity of flood and to increase in the groundwater quantity. Catchment area for Melmuthanur check dam is find out using the software ARC-Gis and the catchment area is divided in three s. Flooding characteristics in the Pambanar sub-basin is simulated using the modeling software HEC-HMS. The quantity of water discharged through the check dam from is determined using the model. The collected data of precipitation and water level in well are plotted in graph and discussions are done to find out the effectiveness of check dam. Water table fluctuation method is used to calculate the recharge near the check dam with the water level in well points available. Conclusion After the construction of Check dam the volume of water discharged is increased. Although the loss of precipitation is high during some seasons, the recharge of ground water is high after the completion of check dam in year 011. The performance of check dam in my study area located in Melmuthanur is MODERATLY EFFECTIVE. References 1. Babak S. D., MohdehMoradi.andBorujerdi. A. M., Flood Forecasting using HEC-HMS (Case Study: Maroon Catchment- Upstream OfBehbahan). ICID 1st International Congress on Irrigation and Drainage, October 011. Summary Check dam are generally constructed as rain water harvesting structures to reduce the. Christian Michl. Using GIS, MODFLOW and MODPATH for groundwater management of an aquifer of the River Sieg, Germany.HydroGIS 96: 10

5 Application of Geographic Information Systems in Hydrology and Water Resources Management (Proceedings of the Vienna Conference, April 1996). IAHS Publ. no. 5, Kure.S., Watanabe A., and Y.Akabane. Field Observations of Discharge and Runoff Characteristics in urban catchments Area.11 th International Conference on Urban Drainage, Edinburgh, Scotland, UK, 008 flood control structures, January 00, International Institute for Geo-information science and Earth observation, Netherlands 5. Sastry.G., Reddy. Y.V.R. and Singh.H.P. Watershed based land management treatments for augmenting and sustaining water resources in different semi-arid regions of India. Central Research Institute for Dry land AgricultureRes. & Dev (1), pp Reza. Roshani Evaluating the effect of check dams on flood peaks to optimise the 11