1. Areas of Intensive ground water development
2. Areas with high surface irrigation application
3. Growing urban complexes
4. The industrial establishments
5. Areas of intensive mining activities

1. Areas of Intensive ground water development:
   The overall stage of development of ground water is low, generally in the range of 6.29% in Bastar district to 53.99% in Dhamtari district. However there are few pockets of intensive development. Out of 146 blocks. Stage of ground water development in 4 blocks has crossed 70%. Gurur Block in Durg district has the highest stage of ground water development (84.6%). Four blocks (Balod, Saja, Baramkela, and Belha) have stages of ground water development between 60 and 70%. All other blocks have stage of development less than 60%. It is well known that as a consequence of significant development, ground water levels will initially decline. However, if the withdrawal is restricted within annual replenishable recharge limits, the system shall in due coarse attain a new equilibrium at lower level. When the withdrawal exceeds the latter, a declining trend in water levels will set in. Analyze of long term-term data (more than 15 years) shows declining ground water level trend in few monitoring stations. These stations are Saraipali (Raipur) Kondagaon, & Charama (Bastar). Infew blocks of Raigarh, Bilaspur, Durg, Rajnandgaon, Raipur and Dhamtari Districts the depth to water level in pre monsoon ranges between 25-60 in bore wells.
   
   
2. Areas with high surface irrigation application:
   When used for Irrigation by flooding technique only about one half to two third of total quantum of applied water is consumed by crops by evapo-transpiration or lost as field evaporation. The balance either joins directly the ground water reservoir or drains to the surface channels from where it percolates. The return flow of irrigation water is normally saline than the water in underlying aquifer system. The salinity of irrigation return flow increases three to ten times of applied water. Principal cations are calcium magnesium and sodium and major anions include bicarbonate, sulphate chloride, and nitrate. The use of nitrogenous fertilizers in intensive agriculture in irrigated areas increases the nitrate content in ground water
   
   Application of large quantities of water also adds to the recharge of ground water body. Where sufficient drainage facilities do not exist, the result is continuous rise in water table and eventual water logging.
   
   3 major, 6 medium and 1945 small irrigation schemes have been constructed so far in the State and 4 major, 9 medium and 398 small schemes are under construction.
   
   The total irrigated land is about 1.6 million hectares (0.66 million hectares is being irrigated by surface water and 0.50 million hectares is being irrigated by ground water) out of the gross sown area of 5.8 million hectors. Hence the present irrigated land is only 21%, which is far below the national average of 38%. On the basis of water resources availability in the State the total irrigated land could be 4.3 million hectares that is 75% of the total gross sown land available. Bringing the large additional land under irrigated will effect the hydrogeological cycle in the State. The detailed microlevel studies must be taken up for the conjunctive use and planning be done well in advance to minimize the negative implications.
   
   
3. Growing urban complexes:
   Growing Urban Agglomerates generate large quantity of waste, both liquid and solid. The district towns have not been provides with any facilities for proper treatment/disposal of the wastes. Abandoned quarries and local depressions are converted into land-fill sites. Septic tanks are used for individual household.
   
   The 27% of the area of Chhattisgarh is underlain by carbonate group of rocks in Indravati and Mahanadi Basin. These Karstic limestone terrain are highly sensitive to ground water pollution due to its conduit nature. Through the solution cavities of limestone the leachates percolate down to aquifer. According to a WHO report, 80% of the diseases in the world population are due to consumption of polluted water and Chhattisgarh is no exception. It has been reported and observed every year in the groundwater dependent area that just after the first few shows in June, the complaints of various diseases suddenly increases. This may be due to the fact that leachates percolate down through the karst conduit and contaminate the aquifer. However, subsequent rain dilutes the concentration and makes the system almost normal. The present practice of disposal of solid waste in limestone terrain must be stopped immediately. It is universally accepted that ground water system is polluted slowly but ones polluted its revival is almost impossible. Major towns of Chhattisgarh as Raipur, Durg, Bhilai, Jagdalpur, Bilaspur and Raigarh are underlain by limestone/dolomite characterized often by macropores and super capillary openings. Thus the leachate from the waste can readily percolate and mix with ground water increasing its total dissolved solids (TDS), Nitrogen, Phosphorous and introducing disinfectants, detergents, bacteria and viruses
   
   
4. The industrial establishments:
   The major industrial centers in Chhattsigarh are located at Bhilai, Korba, Raipur, Bilaspur, and Raigarh districts. One of the biggest steel plants of the country and many ancillary industries are located in Bhilai. In Korba, besides a super thermal power station, an aluminum smelter unit is also present. Major cement plants are operating in Raipur Bilaspur area
   
   Thermal power stations using coal emit vast quantities of fly ash and coal dust .If adequate measures are not taken the deposition of these on the surface and water bodies can bring down the infiltration rate and consequently the ground water recharge Water used in manufacturing industry picks up high TDS, acidity or alkalinity, heavy metals such as Cr+6, Cd, As, Hg, Ni, Fe, and Mn. etc. Where water is used for cooking purposes, algae inhibitors and pH adjustors are often used. These results in high temperature (Thermal Pollution), and increase in TDS, acidity, alkalinity etc.
   
   
5. Areas of intensive mining activities:
   Associated with the mining activity is the intensive development of ground water. Smooth and unhindered mining operations necessitate heavy ground water pumping and associate activites like washing of coal, milling etc. Coal mines are extensively developed in Bilaspur, Korba, Raigarh, Sarguja, and Koriya districts. There are reports of declining ground water level in areas surrounding these mines. Extensive mining of iron ore is being undertaken in Bailadila area of Dantewada district and Dalli-Rajhara areas of durg district. Mines can produce a variety of ground water pollution problems. Coal mine is a major contributor. Dewatering of old mines, both surface and underground, is common activity. Pumped water may be highly mineralized. It can often lower pH and indicate high Iron and Sulphate content. It is referred as acid mine drainage.
   
   Oxidation of pyrite, often found in coal deposits, occurs as a result of lowered water level. This, followed by contact with water produces ferrous sulphate and sulphuric acid in solution. When it gets mixed with ground water, the latter will have reduced pH and increase in iron and sulphate contents.
   
   Leachate from old mine tailing and settling ponds also causes ground water pollution. These problems are associated with both active and abandoned mines.
   
   

Taken from:
Emerging Challenges in ground water resources before Chhattsigarh State (T.M.Hunse Superintending Hydrogeologist1, Denesh Tiwari Scientist B2, and Arunangshu Mukerjee Assistant Hydrogeologist3)