The study area is approximately 625 km2 , which includes Kaduna town at the centre with large settlements like Tudun Nupawa, Kurmin Mashi, Mondo and Rigasa to the west; Kabala and Barnawa to the south; Malali and Unguwan Rimi to the east; and Unguwar Kanawa, Badarawa and Rigachukun to the east. The major river channel is the River Kaduna which cuts the area from west to east. Other rivers are River Gora to the south and River Kura to the north. There are many streams in the area. The topography is virtually flat lying and the relief of the area ranges from 590m and 653m.\r\n The entire project area is underlain by Precambrian migmatite-gneiss complex which constitutes a greater part of the project area; the Pan Africa granitoids which constitute the second largest suit of rocks in the area; and lastly Metasediments/metavolcanics; mostly schists. The soils derived from these rocks are gravelly clays, sandy clays, clays and clayey gravels. Gravelly clays cover about 33% (208km2 ) of the area, sandy clays cover about 6% (37km 2 ) of the area, clays cover about 41% ( 256km2 ) of the area, clayey gravels cover about 6% (37km2 ) and alluvial silty clays cover about 12% (80 km2 ) of the area. \r\n Eight geotechnical factors were evaluated for the project area: soil bearing capacity, soil compressibility, soil expansivity, soil permeability, slope instability, soil erodibility, flooding and soil acidity.\r\nReddish-brown to red, stiff to hard, residual lateritic gravelly clays cover about 33% (208km2) of the study area. They have high bearing capacities at shallow depth, low compressibility, and they are virtually free from highly expansive clays. They are therefore good founding materials at shallow depth. They have medium permeability and they are of low to medium plasticity.\r\nReddish-brown to red, stiff to hard residual lateritic sandy clays cover about 6% (37km2) of the study area. They have high bearing capacities at shallow depth, low compressibility and they are virtually free from highly expansive clays. They are therefore good founding materials at shallow depth. They have medium permeability and they are of low to medium plasticity.\r\nReddish-brown to red, stiff to hard residual lateritic clays cover about 41% (256km2) of the study area. They have high bearing capacities at shallow depth, low compressibility and they are free from highly expansive clays. They are therefore good founding materials at shallow depth. They have low permeability and they are of low to medium plasticity.\r\nReddish brown to red, medium dense to dense residual lateritic clayey gravels cover about 6% (37 km2) of the area. They have high bearing capacities at shallow depth, low compressibility and they are free from highly expansive clays. They are therefore good founding materials at shallow depth. They have high permeability and they are of low to medium plasticity.\r\nGrey to brown, soft to firm, alluvial silty clays cover about 12% (80km2) of the area. They have low bearing capacities at shallow depth. They are therefore not good founding materials at shallow depth, especially for heavy loaded structures. They have low compressibility and they are free from highly expansive clays. They also have low permeability and they are of low to medium plasticity.\r\nThe area is flat lying; there are no slopes or erosion sites which will pose a problem in the study area.\r\nThe streams constitute the main flood paths during the rainy season when they overflow their channels and the flood zones are the flood plains and the fadama areas along Rivers Kaduna, Gora, Kura and their tributaries. Flooding is expected for about 10% (65 km2 ) of the study area.\r\nThe entire soils are slightly acidic (pH = 5 or 6 ). The acidity is not strong enough to course any environmental, agricultural or engineering problem.\r\nA total of six geotechnical maps have been produced: (i) suitable and unsuitable sites for housing estate development map (ii) suitable areas for waste disposal map (iii) potential flood zone map (iv) Land form map (v) structural map and (vi) documentation map.\r\nThe geotechnical map showing suitable and unsuitable sites for housing estate development shows that 79% (495 Km2 ) of the area is suitable for light loaded housing estate development (like simple houses with wall load of up to 100 KN /m and 1 or 2 storey houses with column load of up to 250 KN) because the soils have high bearing capacities at shallow depth, low compressibility and they are virtually free from highly expansive clays. The areas are not susceptible to erosion or flooding. The map also shows that about 21% (130 Km2)of the area is not suitable for housing estate development because the soils have low bearing capacities at shallow depth and the areas are susceptible to flooding. \r\nThe geotechnical map showing suitable areas for waste disposal shows that about 5% (32km2 ) of the area is suitable for waste disposal because the soils have low permeability, the areas are flat lying or slightly elevated and far away from settlements. Water tables are also very low.\r\nThe geotechnical map showing potential flood zones area shows that about 10% (65km2) of the study area is susceptible to flooding because the areas are the flood plains and fadama areas of Rivers Kaduna, Gora, Kura and their tributaries. \r\nThe land form map shows elevated flat lying lands, low lying flood plains, fadama areas and water courses.\r\nThe structural map shows fractures, joints and faults in the study area. \r\nThe documentation map shows the positions of 93 trial pits (TP) dug and 16 drill holes ( BH) drilled on a geological map. \r\n

Determination of in-situ soil conditions

Determination of in-situ soil conditions

Fifty-four (54) bulk samples were taken from test pits dug to a minimum depth of 1.5 metres for Atterberg Limits Test, Grain Size Distribution analysis, Compaction, and California Bearing Ratio determination.\r\n\r\nTwelve (12) shell and auger boreholes were drilled using the Pilcon Wayfarer 1500 percussion rig. The boreholes were advanced to 10 metres depth. Undisturbed samples were collected in Shelby tubes at selected intervals of 1.5metre from each other for Triaxial Compression Test, Consolidation test and Grain Size Distribution analysis.\r\n\r\nTwelve (12) Dutch Cone Penetrometer Sounding Tests were carried out at 10 metres depth or to refusal. The resistance of the soil was measured by means of a dial guage attachment to the penetrometer machine. Readings obtained and the graphical plots of the soil resistance were used to determine the allowable bearing pressure of the soil.\r\n\r\nResults of the grain size distribution analysis show a consistent increase in grain size with increasing depth. The soils classify as very fine sands, silty to clayey fine sands, or clayey silts with slight plasticity (ML), and gravelly clays, sandy and silty clays (CL) according to the Unified Soils classification scheme (USC).They have good to poor, and good to fair compaction characteristics respectively. They show high compressibility, moderate permeability and are excavatable and stable as fill material, but would be unsuitable as base course.\r\nTheir bulk density showed a range from 1.95Mg/m3 to 2.19 Mg/m3, their natural moisture, a variation from 12% to 21%, while their optimum moisture content ranges between 9.5% and 19.8%. Cohesion values range from 28 kN/m2 to 60 kN/m2, and maximum dry density ranging between 1.09 Mg/m3 and 2.17 Mg/m3 were recorded. The soaked and unsoaked California Bearing Ratio (CBR) values of 5.1% to 11.2% and 7.6%to18.9% were registered respectively. No ground water was encountered during the operation.\r\nFor design of strip/square footing 1.5metres wide founded at 1.5metres depth, the average allowable bearing capacity of soil would be 25 kN/m2 from cone, while the sleeve gives 50 kN/m2, allowing maximum differential settlement of 25mm (1 inch), using a factor of safety of 3.\r\nFor the same footing, under same conditions, the average allowable bearing capacity would be 125 kN/m2 for Standard Penetration Test, while the average allowable bearing capacity of 279 kN/m2 was computed for same footing under same conditions from the Undrained Triaxial compression Test. \r\n\r\nTherefore, it is recommended that the Dutch Cone Penetration Test average bearing capacity of 25 kN/m2 be used for design. However, it must be ensured that no ingress of water be allowed into the foundation. Alternatively, a raft foundation may be necessary for design. If a pile foundation is adopted, it must be imperative to carry out a pile loading test.\r\n

Determination of in-situ soil conditions

The effects of waste dumps on the groundwater supply in Kano and the environs are being investigated. Water samples were collected from the ubiquitous hand-dug wells which form the major source of water supply to the Kano populace, as 96 of the samples were analyzed for their cation and anion contents. \r\n\r\nThe chemical analyses revealed the presence of Ca2+, Mg2+, Na+, K+, Fe2+ , etc. as cations while anions include: HCO3-, Cl-, SO42-, NO3-. The chemical analyses also showed that the groundwater is polluted by leachates from the waste dumps because the values of total dissolved solids, conductivity and salinity were very high in wells near the dumpsites. For instance, at the Court Road dumpsite in Kano metropolis, the total dissolved solids in the wells near it were 983mg/l, conductivity 2000 microsiemens and pH 7.8, while at Yanlemu dumpsite, the total dissolved solids was 1240mg/l conductivity 2520 microsiemens and a high chlorine content of 16.2mg/l. The pH ranged from 5.57 to 7.60 though with most values between 6.0-7.0.\r\n\r\nMicrobial analyses showed that the wells are polluted by micro-organisms like Escherichia coli that could cause epidemic of cholera and such gastrointestinal diseases.\r\n\r\nThe Vertical Electrical Sounding (VES) was used to complement the hydrogeological mapping. A total of 24 VES points were chosen based on different lithologies. It was deduced by the VES that the depths of the topsoil (mainly laterites) to the weathered basement, which is the aquifer, varied from 0.4 - 13.1metres. \r\n\r\n\r\nSieve analysis was performed to further complement the study of the groundwater infiltration. The silty, medium and coarse gravels permit passage of rainwater into the vadose zones and thence to the water-table.\r\n\r\nThe state government could reduce reliance on wells especially for domestic use by providing adequate tap water to the populace. Such will increase the quality of life and improve the economy of the area.\r\n

The study area, Abeokuta and its environs, is located in Ogun State, south western Nigeria. It is defined by latitudes 07° 3.0´ to 7° 17.0'N and longitudes 003° 14.0' to 003° 28.0'E and falls within 1:100,000 Sheet 260 Abeokuta and covers an area of 625km2.\r\n\r\nThe objective of the project is to study the hydrogeological characteristics of the area and the impact of waste dumps on the water quality. \r\n\r\nThe area is predominantly underlain by rocks of the Basement Complex and partly by the Cretaceous Sedimentary rocks of the Dahomey Basin. The rocks encountered in order of abundance are migmatized biotite-garnet gneiss, red sand, biotite schist, biotite-garnet-gneiss, coarse porphyritic granite, porphyroblastic gneiss, biotite granite, pegmatite and quartz vein. \r\n\r\nThe physical, chemical and microbial analyses of water samples (surface and groundwater) showed high conductivity, high concentration of trace elements and the presence of pathogens (Esherichia coli) in nearly all the water samples that is within a range of 14 - 180 CFU/ml indicating anthropogenic influence on the groundwater quality. The water samples are all beyond the W.H.O. and S.O.N accepted drinking water standards for human consumption.\r\n\r\nRemediating measures such as provision of pipe-borne water, construction of central sewer system, enactment and enforcement of sanitary bye-laws and location of waste dumpsites are recommended to ameliorate the problems of groundwater pollution in the area. \r\n

Determination of in-situ soil conditions

Hydrogeology, geology and geophysics were used to study the groundwater potentials of Ibadan and its environs. These potentials include quantity, quality and availability of groundwater to the masses of the people. Due to the factor of affordability, hand dug wells are more in use than deep bore holes which are exclusively for the rich. \r\n\r\nRecords from 690 sample points such as wells, bore holes, streams and the results from ninety-three (93) analyzed water samples form the basis of conclusion and recommendations in this report.\r\n\r\nChemical analysis shows HCO3+CO3 dominated water with low to medium salinity hazard. Nitrate is too low there by allaying the fear of present level of contamination. \r\n\r\nIncident of groundwater contamination by leachates could be a problem in the immediate future because of indiscriminate dumping of solid wastes in unauthorized locations and river system. Lowering of groundwater level due to over extraction should be prevented with appropriate laws. The quality of water is fair as more than half of respondents claim they only use the water for domestic chores except drinking. Microbial contamination is average as most wells lack proper hygiene. \r\n\r\nContinuous monitoring and education is necessary to safe guard the groundwater resources of Ibadan and environs.\r\n

The study area is between Latitudes 080 46' - 090 00'E and Longitudes 090 48' - 10 02'N and covers an area of about 635km2. The area covers about 5 local governments: Jos North, Jos South, Jos East, Bassa and some parts of Toro Local Government in Bauchi state. \r\n\r\nThe topography of the area is virtually undulating. The undulations are due to the rocky nature of the terrain and several water paths that follow the basement structure. The area is covered with high relief older granite plutons and younger granite ring complexes.\r\n\r\nThe geology of this area can be divided into six major lithological groups: (i) the precambrian migmatites and granite gneisses of the basement complex covering an area of about 97km2 (i.e. 15%) in the Central and Northern parts of the map; (ii) the pan-African older granites comprising of coarse porphyritic biotite and biotite hornblende granite and fine grained biotite granite occupying an area of about 83km2 (i.e. 13%) in the Western margin and Central part of the map; (iii) the Jurassic younger granite series comprising of granite and porphyries occupying an area of about 349km2 (i.e. 55%) in the Central, South East, North West and North Eastern parts of the map; (iv) the late cretaceous older basalts occupying an area of about 25km2 (i.e. 4%) in the South-Western and North Western parts of the map (v) the late tertiary/quartenary newer basalts occupying an area of about 36km2 (i.e. 10%) in the Central part of the map; and (vi) the Neogene sediments (Alluvium) occupying an area of about 25km2 (i.e. 4%) along the rivers in the entire area.\r\n\r\nStreams, rivers, springs and mining ponds provide the surface water resources of the area. The major Rivers in the area are River Bauna, River Dilimi, River Tilden Fulani, River Rukuba, River Gell and Shen River. The drainage pattern of all the rivers and streams in the area is controlled by chains of mountains and hills of high relief on the Jos Plateau. \r\n \r\nGroundwater in this area occurs in 4 different aquifer types: (i) the weathered or overburden or regolith aquifer (ii) the fractured basement rock aquifer (iii) the alluvium aquifer and (iv) the fluvio-volcanic aquifer. The overburden or regolith aquifer is the main aquifer in the study area which provides water to about 95% of the population via hand-dug wells. The aquifer is unconfined. It is discontinuous due to the rocky nature of the area. It is generally clayey. It is porous but not very permeable. The water table ranges from less than 3m in the rainy season to a maximum of 10m in the dry season. The younger granite in the study area is characterized by a pronounced set of open joints which show a persistent northerly trend and contain a lot of water. As a result shallow ground water occurs almost every where in the decomposed zone (regolith aquifer) overlying the fresh rock. This is extremely developed for domestic purposes by means of numerous hand-dug wells.\r\n\r\nThe electrical resistivity survey carried out at 16 locations in the area shows that the basement rocks of Jos appear to be highly weathered and fractured hence, the area has high water potential. The survey also shows that the depth to the probable aquiferous layer varies between 9.4m and 42. 5m. Since the basement in the study area is shallow and in most cases fractured, contaminants/leachates could easily find their way to pollute the ground water. \r\n\r\nThe waters in the wells and streams of Jos town and its surroundings villages are dominantly calcium bicarbonate (Ca-HCO3) and sodium chloride bicarbonate (Na-Cl-HCO3) waters. This is because of the dominance of Ca++, Cl-, Na+ and HCO3- ions in the waters. \r\n\r\nThe regolith aquifers in the surrounding villages and some parts of Jos town (like the G. R. A and millionaires quarters) show relatively low mineral content (TDS of 4.83 to 169 ppm) while concentrations in excess of 958 ppm occur within the congested parts of Jos town where land surface derived wastes contribute to the excess. \r\n\r\n94% of the water samples are slightly acidic with the pH range of 5.1 - 6.9 while 6% of samples are slightly alkaline with the pH range of 7.1 - 8.8. The moderately low pH values (i.e. 5.1 - 6.9) or the slightly acidic nature of the samples may be due to the clay rich nature of the overburden weathered sediments of the basement rocks. The pH values of water samples in the study area (i.e. 5.1 - 7.88) have nearly fallen within the permissible range for drinking water recommended by WHO, NAFDAC and NPDWR (USA) which are 7.0 - 8.5, 6.5 - 8.5 and 6.5 - 8.5 respectively. Therefore, in terms of pH, the waters in the regolith aquifers in the study area are good for drinking, washing and cooking. \r\n\r\nThe amount of all the cations and anions present in the waters of all the hand-dug wells and streams studied cannot pose any problem, as regards drinking washing, bathing and other domestic uses when compared with the WHO, NAFDAC and NPDWR (USA) standards for drinking water. The waters are also free from deleterious metals like copper and arsenic. The waters that contain high total dissolved solids in the study area were found to contain a lot chloride and nitrate. The chloride is in excess of 172 mg/liter at location 282 (Dodo Street) and the Nitrate is in excess of 43 mg/liter at location 289 (Abba Na Shehu Street). This is due to the leachates from the numerous waste dumps around as confirmed by the medium permeability of the 4 soil samples collected from the bottoms of 4 refuse dumps in this area. The presence of nitrates in all the samples is a sign of pollution from inorganic wastes and fertilizers used in the farms.\r\n\r\nGenerally, the levels of faecal pollution in the well waters of Jos town and the surrounding villages are high. This could be connected to the (i) siting of wells near pit latrines or septic tanks or refuse damps; (ii) using contaminated containers to fetch water; (iii) throwing of containers used for fetching water on the ground near the wells when not in use; (iv) washing dishes near the wells (v) leaving the wells open when not in use; (v) presence of animals and chickens near the well.\r\nThe study area is between Latitudes 080 46' - 090 00'E and Longitudes 090 48' - 10 02'N and covers an area of about 635km2. The area covers about 5 local governments: Jos North, Jos South, Jos East, Bassa and some parts of Toro Local Government in Bauchi state. \r\n\r\nThe topography of the area is virtually undulating. The undulations are due to the rocky nature of the terrain and several water paths that follow the basement structure. The area is covered with high relief older granite plutons and younger granite ring complexes.\r\n\r\nThe geology of this area can be divided into six major lithological groups: (i) the precambrian migmatites and granite gneisses of the basement complex covering an area of about 97km2 (i.e. 15%) in the Central and Northern parts of the map; (ii) the pan-African older granites comprising of coarse porphyritic biotite and biotite hornblende granite and fine grained biotite granite occupying an area of about 83km2 (i.e. 13%) in the Western margin and Central part of the map; (iii) the Jurassic younger granite series comprising of granite and porphyries occupying an area of about 349km2 (i.e. 55%) in the Central, South East, North West and North Eastern parts of the map; (iv) the late cretaceous older basalts occupying an area of about 25km2 (i.e. 4%) in the South-Western and North Western parts of the map (v) the late tertiary/quartenary newer basalts occupying an area of about 36km2 (i.e. 10%) in the Central part of the map; and (vi) the Neogene sediments (Alluvium) occupying an area of about 25km2 (i.e. 4%) along the rivers in the entire area.\r\n\r\nStreams, rivers, springs and mining ponds provide the surface water resources of the area. The major Rivers in the area are River Bauna, River Dilimi, River Tilden Fulani, River Rukuba, River Gell and Shen River. The drainage pattern of all the rivers and streams in the area is controlled by chains of mountains and hills of high relief on the Jos Plateau. \r\n \r\nGroundwater in this area occurs in 4 different aquifer types: (i) the weathered or overburden or regolith aquifer (ii) the fractured basement rock aquifer (iii) the alluvium aquifer and (iv) the fluvio-volcanic aquifer. The overburden or regolith aquifer is the main aquifer in the study area which provides water to about 95% of the population via hand-dug wells. The aquifer is unconfined. It is discontinuous due to the rocky nature of the area. It is generally clayey. It is porous but not very permeable. The water table ranges from less than 3m in the rainy season to a maximum of 10m in the dry season. The younger granite in the study area is characterized by a pronounced set of open joints which show a persistent northerly trend and contain a lot of water. As a result shallow ground water occurs almost every where in the decomposed zone (regolith aquifer) overlying the fresh rock. This is extremely developed for domestic purposes by means of numerous hand-dug wells.\r\n\r\nThe electrical resistivity survey carried out at 16 locations in the area shows that the basement rocks of Jos appear to be highly weathered and fractured hence, the area has high water potential. The survey also shows that the depth to the probable aquiferous layer varies between 9.4m and 42. 5m. Since the basement in the study area is shallow and in most cases fractured, contaminants/leachates could easily find their way to pollute the ground water. \r\n\r\nThe waters in the wells and streams of Jos town and its surroundings villages are dominantly calcium bicarbonate (Ca-HCO3) and sodium chloride bicarbonate (Na-Cl-HCO3) waters. This is because of the dominance of Ca++, Cl-, Na+ and HCO3- ions in the waters. \r\n\r\nThe regolith aquifers in the surrounding villages and some parts of Jos town (like the G. R. A and millionaires quarters) show relatively low mineral content (TDS of 4.83 to 169 ppm) while concentrations in excess of 958 ppm occur within the congested parts of Jos town where land surface derived wastes contribute to the excess. \r\n\r\n94% of the water samples are slightly acidic with the pH range of 5.1 - 6.9 while 6% of samples are slightly alkaline with the pH range of 7.1 - 8.8. The moderately low pH values (i.e. 5.1 - 6.9) or the slightly acidic nature of the samples may be due to the clay rich nature of the overburden weathered sediments of the basement rocks. The pH values of water samples in the study area (i.e. 5.1 - 7.88) have nearly fallen within the permissible range for drinking water recommended by WHO, NAFDAC and NPDWR (USA) which are 7.0 - 8.5, 6.5 - 8.5 and 6.5 - 8.5 respectively. Therefore, in terms of pH, the waters in the regolith aquifers in the study area are good for drinking, washing and cooking. \r\n\r\nThe amount of all the cations and anions present in the waters of all the hand-dug wells and streams studied cannot pose any problem, as regards drinking washing, bathing and other domestic uses when compared with the WHO, NAFDAC and NPDWR (USA) standards for drinking water. The waters are also free from deleterious metals like copper and arsenic. The waters that contain high total dissolved solids in the study area were found to contain a lot chloride and nitrate. The chloride is in excess of 172 mg/liter at location 282 (Dodo Street) and the Nitrate is in excess of 43 mg/liter at location 289 (Abba Na Shehu Street). This is due to the leachates from the numerous waste dumps around as confirmed by the medium permeability of the 4 soil samples collected from the bottoms of 4 refuse dumps in this area. The presence of nitrates in all the samples is a sign of pollution from inorganic wastes and fertilizers used in the farms.\r\n\r\nGenerally, the levels of faecal pollution in the well waters of Jos town and the surrounding villages are high. This could be connected to the (i) siting of wells near pit latrines or septic tanks or refuse damps; (ii) using contaminated containers to fetch water; (iii) throwing of containers used for fetching water on the ground near the wells when not in use; (iv) washing dishes near the wells (v) leaving the wells open when not in use; (v) presence of animals and chickens near the well.\r\nThe study area is between Latitudes 080 46' - 090 00'E and Longitudes 090 48' - 10 02'N and covers an area of about 635km2. The area covers about 5 local governments: Jos North, Jos South, Jos East, Bassa and some parts of Toro Local Government in Bauchi state. \r\n\r\nThe topography of the area is virtually undulating. The undulations are due to the rocky nature of the terrain and several water paths that follow the basement structure. The area is covered with high relief older granite plutons and younger granite ring complexes.\r\n\r\nThe geology of this area can be divided into six major lithological groups: (i) the precambrian migmatites and granite gneisses of the basement complex covering an area of about 97km2 (i.e. 15%) in the Central and Northern parts of the map; (ii) the pan-African older granites comprising of coarse porphyritic biotite and biotite hornblende granite and fine grained biotite granite occupying an area of about 83km2 (i.e. 13%) in the Western margin and Central part of the map; (iii) the Jurassic younger granite series comprising of granite and porphyries occupying an area of about 349km2 (i.e. 55%) in the Central, South East, North West and North Eastern parts of the map; (iv) the late cretaceous older basalts occupying an area of about 25km2 (i.e. 4%) in the South-Western and North Western parts of the map (v) the late tertiary/quartenary newer basalts occupying an area of about 36km2 (i.e. 10%) in the Central part of the map; and (vi) the Neogene sediments (Alluvium) occupying an area of about 25km2 (i.e. 4%) along the rivers in the entire area.The Federal Government of Nigeria should formulate a stringent regulation to force the states Governments to always design, construct and monitor landfills in their states and also to force their people to take the refuse collected to the designated landfills.\r\n\r\nStreams, rivers, springs and mining ponds provide the surface water resources of the area. The major Rivers in the area are River Bauna, River Dilimi, River Tilden Fulani, River Rukuba, River Gell and Shen River. The drainage pattern of all the rivers and streams in the area is controlled by chains of mountains and hills of high relief on the Jos Plateau. \r\n \r\nGroundwater in this area occurs in 4 different aquifer types: (i) the weathered or overburden or regolith aquifer (ii) the fractured basement rock aquifer (iii) the alluvium aquifer and (iv) the fluvio-volcanic aquifer. The overburden or regolith aquifer is the main aquifer in the study area which provides water to about 95% of the population via hand-dug wells. The aquifer is unconfined. It is discontinuous due to the rocky nature of the area. It is generally clayey. It is porous but not very permeable. The water table ranges from less than 3m in the rainy season to a maximum of 10m in the dry season. The younger granite in the study area is characterized by a pronounced set of open joints which show a persistent northerly trend and contain a lot of water. As a result shallow ground water occurs almost every where in the decomposed zone (regolith aquifer) overlying the fresh rock. This is extremely developed for domestic purposes by means of numerous hand-dug wells.\r\n\r\nThe electrical resistivity survey carried out at 16 locations in the area shows that the basement rocks of Jos appear to be highly weathered and fractured hence, the area has high water potential. The survey also shows that the depth to the probable aquiferous layer varies between 9.4m and 42. 5m. Since the basement in the study area is shallow and in most cases fractured, contaminants/leachates could easily find their way to pollute the ground water. \r\n\r\nThe waters in the wells and streams of Jos town and its surroundings villages are dominantly calcium bicarbonate (Ca-HCO3) and sodium chloride bicarbonate (Na-Cl-HCO3) waters. This is because of the dominance of Ca++, Cl-, Na+ and HCO3- ions in the waters. \r\n\r\nThe regolith aquifers in the surrounding villages and some parts of Jos town (like the G. R. A and millionaires quarters) show relatively low mineral content (TDS of 4.83 to 169 ppm) while concentrations in excess of 958 ppm occur within the congested parts of Jos town where land surface derived wastes contribute to the excess. \r\n\r\n94% of the water samples are slightly acidic with the pH range of 5.1 - 6.9 while 6% of samples are slightly alkaline with the pH range of 7.1 - 8.8. The moderately low pH values (i.e. 5.1 - 6.9) or the slightly acidic nature of the samples may be due to the clay rich nature of the overburden weathered sediments of the basement rocks. The pH values of water samples in the study area (i.e. 5.1 - 7.88) have nearly fallen within the permissible range for drinking water recommended by WHO, NAFDAC and NPDWR (USA) which are 7.0 - 8.5, 6.5 - 8.5 and 6.5 - 8.5 respectively. Therefore, in terms of pH, the waters in the regolith aquifers in the study area are good for drinking, washing and cooking. \r\n\r\nThe amount of all the cations and anions present in the waters of all the hand-dug wells and streams studied cannot pose any problem, as regards drinking washing, bathing and other domestic uses when compared with the WHO, NAFDAC and NPDWR (USA) standards for drinking water. The waters are also free from deleterious metals like copper and arsenic. The waters that contain high total dissolved solids in the study area were found to contain a lot chloride and nitrate. The chloride is in excess of 172 mg/liter at location 282 (Dodo Street) and the Nitrate is in excess of 43 mg/liter at location 289 (Abba Na Shehu Street). This is due to the leachates from the numerous waste dumps around as confirmed by the medium permeability of the 4 soil samples collected from the bottoms of 4 refuse dumps in this area. The presence of nitrates in all the samples is a sign of pollution from inorganic wastes and fertilizers used in the farms.\r\n\r\nGenerally, the levels of faecal pollution in the well waters of Jos town and the surrounding villages are high. This could be connected to the (i) siting of wells near pit latrines or septic tanks or refuse damps; (ii) using contaminated containers to fetch water; (iii) throwing of containers used for fetching water on the ground near the wells when not in use; (iv) washing dishes near the wells (v) leaving the wells open when not in use; (v) presence of animals and chickens near the well.\r\nThe study area is between Latitudes 080 46' - 090 00'E and Longitudes 090 48' - 10 02'N and covers an area of about 635km2. The area covers about 5 local governments: Jos North, Jos South, Jos East, Bassa and some parts of Toro Local Government in Bauchi state. \r\n\r\nThe topography of the area is virtually undulating. The undulations are due to the rocky nature of the terrain and several water paths that follow the basement structure. The area is covered with high relief older granite plutons and younger granite ring complexes.\r\n\r\nThe geology of this area can be divided into six major lithological groups: (i) the precambrian migmatites and granite gneisses of the basement complex covering an area of about 97km2 (i.e. 15%) in the Central and Northern parts of the map; (ii) the pan-African older granites comprising of coarse porphyritic biotite and biotite hornblende granite and fine grained biotite granite occupying an area of about 83km2 (i.e. 13%) in the Western margin and Central part of the map; (iii) the Jurassic younger granite series comprising of granite and porphyries occupying an area of about 349km2 (i.e. 55%) in the Central, South East, North West and North Eastern parts of the map; (iv) the late cretaceous older basalts occupying an area of about 25km2 (i.e. 4%) in the South-Western and North Western parts of the map (v) the late tertiary/quartenary newer basalts occupying an area of about 36km2 (i.e. 10%) in the Central part of the map; and (vi) the Neogene sediments (Alluvium) occupying an area of about 25km2 (i.e. 4%) along the rivers in the entire area.\r\n\r\nStreams, rivers, springs and mining ponds provide the surface water resources of the area. The major Rivers in the area are River Bauna, River Dilimi, River Tilden Fulani, River Rukuba, River Gell and Shen River. The drainage pattern of all the rivers and streams in the area is controlled by chains of mountains and hills of high relief on the Jos Plateau. \r\n \r\nGroundwater in this area occurs in 4 different aquifer types: (i) the weathered or overburden or regolith aquifer (ii) the fractured basement rock aquifer (iii) the alluvium aquifer and (iv) the fluvio-volcanic aquifer. The overburden or regolith aquifer is the main aquifer in the study area which provides water to about 95% of the population via hand-dug wells. The aquifer is unconfined. It is discontinuous due to the rocky nature of the area. It is generally clayey. It is porous but not very permeable. The water table ranges from less than 3m in the rainy season to a maximum of 10m in the dry season. The younger granite in the study area is characterized by a pronounced set of open joints which show a persistent northerly trend and contain a lot of water. As a result shallow ground water occurs almost every where in the decomposed zone (regolith aquifer) overlying the fresh rock. This is extremely developed for domestic purposes by means of numerous hand-dug wells.\r\n\r\nThe electrical resistivity survey carried out at 16 locations in the area shows that the basement rocks of Jos appear to be highly weathered and fractured hence, the area has high water potential. The survey also shows that the depth to the probable aquiferous layer varies between 9.4m and 42. 5m. Since the basement in the study area is shallow and in most cases fractured, contaminants/leachates could easily find their way to pollute the ground water. \r\n\r\nThe waters in the wells and streams of Jos town and its surroundings villages are dominantly calcium bicarbonate (Ca-HCO3) and sodium chloride bicarbonate (Na-Cl-HCO3) waters. This is because of the dominance of Ca++, Cl-, Na+ and HCO3- ions in the waters. \r\n\r\nThe regolith aquifers in the surrounding villages and some parts of Jos town (like the G. R. A and millionaires quarters) show relatively low mineral content (TDS of 4.83 to 169 ppm) while concentrations in excess of 958 ppm occur within the congested parts of Jos town where land surface derived wastes contribute to the excess. \r\n\r\n94% of the water samples are slightly acidic with the pH range of 5.1 - 6.9 while 6% of samples are slightly alkaline with the pH range of 7.1 - 8.8. The moderately low pH values (i.e. 5.1 - 6.9) or the slightly acidic nature of the samples may be due to the clay rich nature of the overburden weathered sediments of the basement rocks. The pH values of water samples in the study area (i.e. 5.1 - 7.88) have nearly fallen within the permissible range for drinking water recommended by WHO, NAFDAC and NPDWR (USA) which are 7.0 - 8.5, 6.5 - 8.5 and 6.5 - 8.5 respectively. Therefore, in terms of pH, the waters in the regolith aquifers in the study area are good for drinking, washing and cooking. \r\n\r\nThe amount of all the cations and anions present in the waters of all the hand-dug wells and streams studied cannot pose any problem, as regards drinking washing, bathing and other domestic uses when compared with the WHO, NAFDAC and NPDWR (USA) standards for drinking water. The waters are also free from deleterious metals like copper and arsenic. The waters that contain high total dissolved solids in the study area were found to contain a lot chloride and nitrate. The chloride is in excess of 172 mg/liter at location 282 (Dodo Street) and the Nitrate is in excess of 43 mg/liter at location 289 (Abba Na Shehu Street). This is due to the leachates from the numerous waste dumps around as confirmed by the medium permeability of the 4 soil samples collected from the bottoms of 4 refuse dumps in this area. The presence of nitrates in all the samples is a sign of pollution from inorganic wastes and fertilizers used in the farms.\r\n\r\nGenerally, the levels of faecal pollution in the well waters of Jos town and the surrounding villages are high. This could be connected to the (i) siting of wells near pit latrines or septic tanks or refuse damps; (ii) using contaminated containers to fetch water; (iii) throwing of containers used for fetching water on the ground near the wells when not in use; (iv) washing dishes near the wells (v) leaving the wells open when not in use; (v) presence of animals and chickens near the well.\r\n