Effect of Submergence on Groundwater Recharge: An Experimental Study Dr. Javed Alam Associate Professor, Department of Civil Engineering, Z. H. College of Engineering & Technology, AMU Aligarh, INDIA.

WE NEVER KNOW THE WORTH OF WATER TILL THE WELL IS DRY Thomas Fuller, Gnomologia, 1732

WATER DISTRIBUTION ON GLOBE Surface covered by water 71% Water in the ocean 97% Ice Capes 2% Very Deep water 0.31% Available water 0.69%

WATER SCARCITY Water is becoming a rare resource in the world, about 1/3 rd of world’s population lives in water stressed countries. India occupies only 3.29 million km2 geographical area which form 2.4% of the worlds land area, it supports over 15% of world's population with only 4% of the world's water resources. India is facing a water crisis and by 2025 it is estimated that India's population will be suffering from severe water scarcity.

Contd. International Water Management Institute predicts that by 2025, one person in three will live in conditions of absolute water scarcity in India (IWMI, 2003). With increase in population, there will be an increase in stress on sanitation and wastewater disposal system. Gupta et al., (2004) predicted that recyclable wastewater will meet 15% of total water requirement in Total water requirement of the country in 2050 is estimated to be about 1450 km3 which is higher than the current availability of 1086 km3. (Kumar et al., 2005).

Causes of Water Scarcity Lake of awareness regarding importance of water. Population outburst. Vast developments and urbanization of cities. Elevated living styles. Inadequate water supply arrangements. Decrease in the rain fall. Excessive withdrawals of the ground water

Present utilization and future requirement of water by 2025 AD, unit M ha/m (Bandyopadhyay 1989) Utilization (1985) Future requirement (2025 AD) Water use Surface water Ground water Total Surface water Ground water Total Irrigation Domestic Industrial Power Supply Pisciculture Forestry Livestock Navigation Pollution Recreation Total Demand Total utilizable Percentage

Source: Asian Development Bank, “Water for All: The Water Policy of the Asian Development Bank” Decline in Water Resource Per Capita ( )

EFFECTS OF FALLING WATER TABLE Falling water tables are also compounding the fluorosis epidemic in India. Fluoride is a common component of geologic materials underlying much of India. Fluorosis, a medical condition caused by over-consumption of fluoride, has health effects that range from stiff joints to cancer. As groundwater levels continuously decline, villagers are forced to drill wells past safe surface zones into the portions of aquifers that house toxic waters. India’s Fluorosis and Rural Development Foundation now estimates 60 million people currently suffer some degree of the disease.

Government Initiatives After rain water harvesting, In the metropolitan cities of India particularly in Mumbai,the civic body has passed the by-laws and included it in the development control (DC) rule to make it compulsory for all new residential and commercial building. Now the civic body is planning not to issue occupation certificate without the grey water recycling plan for up-coming buildings. It will be applicable to all building projects where the plot size is 20,000 sq feet and above.

INFILTRATION  Infiltration is governed by two forces: gravity and capillary action. While smaller pores offer greater resistance to gravity, very small pores pull water through capillary action in addition to and even against the force of gravity.  The rate of infiltration is determined by soil characteristics including ease of entry, storage capacity, and transmission rate through the soil. The soil texture and structure, water content of the soil, soil temperature, duration and intensity of rainfall, nature of ground slope, vegetation types and cover, all play important role in controlling infiltration rate and capacity.  Once water has infiltrated the soil it remains in the soil, percolates down to the ground water table, or becomes part of the subsurface runoff process.

Soil Profile This study has modelled the soil profile of Civil Lines, Aligarh. Following types of soils were found from top to bottom, in the four bore holes at the site of the Civil Line Aligarh. ML-SMSilt sand mixture with clay traces up to 3.0 m MLSilts and very fine sands with traces of clay from 3.0 to 4.5 m and also from 6.0 to 7.5 CLSilty clays/ Lean clays from 4.5 to 6.0 m SMSilty Sands from 7.5 to 10 m.

Experimental setup of apparatus

RAINFALL AND CLIMATE  Aligarh district is situated on the western part of UP, occupying a small part of Ganga - Yamuna doab.  It lies between latitudes ’ and ’N and longitudes ’00” and ’00”E, falling in Survey of India topographic sheets No. 53H, 53L and 54E.  The normal annual rainfall is 708.7mm. The standard deviation is 58.4 with coefficient of variance 8.20%.  The maximum rainfall occurs during the monsoon period between June to September. July is the wettest month.  Maximum temperature rises up to 45 0 C during May and minimum temperature goes below 5 0 C during January with an average of around 18 0 C.  The average annual wind velocity ranges between 4.6 and 9.3 km/hr.

Gradation curve of sand

Movement of Water in Unconsolidated Medium Water Head (cm)Thickness of sand replacing soil Infiltration (Days) Water Collection at the bottom of The Setup 5 None10 No water was collected 1/410 1/210 3/410 None10 No water was collected 1/410 1/210 3/ None10 Water was collected 1/49 days 6 hours ½6 days 4 hours 3/446 hours

Conclusion The outcome of the study is that for ground water recharge during rain through the process of infiltration is possible only if three fourth of the depth of top compacted and clogged soil is replaced by a pervious material like sand to recharge the top or water table aquifer. The depth of submergence should be more than 30 cm with availability of submergence time more than 46 hours. For more then one billion people of India, though hidden from the naked eye, groundwater depletion is a real and serious issue deserve political and humanitarian attention.

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