Understanding water quality used for irrigation and its potential negative impacts on crop growth are important for optimization of crop production. The study involved the assessment of hydro-chemical properties and chemical indices of Owiwi river for irrigation of vegetables from the measured quality parameters and analyzed for important quality indices following standard test procedures. The study revealed that pH of water was acidic in nature resulting in low residual sodium carbonate (RSC) values showing dominance of dissolved CO3, attributed to dissolution of limestone dominant in the study area. The water was regarded as permissible water based on electrical conductivity (EC) and total dissolved solids (TDS), implying non detrimental salinity hazard in the soils. Excessive Na content (> 250 MMg/L) in water reduces the permeability thereby influencing availability of water for the plant usage, obviously associated with low EC and sodium adsorption ratio (SAR) observed in the river water. The excess hardness resulting from high content of calcium and magnesium ions derived from limestone and chalk is undesirable mostly for esthetic reasons like plumbing of irrigation systems. Generally, the water can be classified as good for irrigation of vegetable on the bases of PI, MAR, % Na, SAR and % yield. Keywords: Hydro-chemical, permeability, soil, limestone, yield.

Geographical information system (GIS) technique is a useful tool for spatial analysis which has not been fully exploited in solving water issues in Ota hence the study. The study applied the tool of GIS in the planning and improvement of water supply system in Ota, Ogun state. This study harnessed the synergy of GIS and engineering designs to proffer an acceptable solution to the problems of water supply in the study area. Primary data generated on the field with GPS and spatial information were analysed with the aid of GIS to produce contour pattern and Digital Elevation Model (DEM) in form of maps. The study noted that the population would increase to almost double the present population by the year 2040 invariably resulting to an increase in water demand of the population beyond the capacity of the existing water supply facilities. Results also showed that water demand by the projected population by year 2040 will increase to 68.37 million litres per day while the existing facility has the capacity to produce about 9.2 million litres per day. Maps produced by the study included Contour, Digital Elevation and Existing and proposed pipeline network maps. These maps made available more information which can then be used for improving the water supply system. The study proffered a lasting solution through design of water scheme with capacity large enough to cater for water requirement of the population for the next twenty-five years irrespective of variation in water need of individual residents in the area with designs to improve distribution system through extension of pipelines and identification of various locations for service reservoirs. © JASEM http://dx.doi.org/10.4314/jasem.v20i4.26

Intensive temporal sampling of Rainwater Harvesting System from three rooftops runoff from a catchment at Okelantoro Community in Abeokuta, Southwest Nigeria was carried out to assess the effect of thunderstorm on the water quality. Assessment was undertaken according to different physical and chemical parameters including biological oxygen demand (BOD), Dissolved oxygen (DO), electric conductivity (EC), Alkalinity, Total hardness (TH) and some major cations and anions. Results showed strong dilution effects in the variation in harvested rainwater quality with thunderstorm and rainstorm s, however, the rainwater harvested under thunder storm had less pollution as compared to water harvested from rain storm. The asbestos roofing sheet water sample gave higher calcium and magnesium content which reflects in the total hardness value. Sample from the aluminum roofing sheet gave the best result but it was also affected by the influence of atmospheric dust particles associated with strong winds that is associated with tropical storms. Considering the results of the physico-chemical tests, irrespective of storm, the harvested water samples could be put to other domestic uses, as they cannot be consumed directly

This paper deals with pollution aspect of environmental management and monitoring of the continental shores of the Lagos Lagoon for its sustainable development. The water quality assessment of coastal waters, at the principal locations of the lagoon susceptible to high level of pollution in the Ebute-Metta and Eti-Osa axis of the Lagos Lagoon was performed. Assessment was undertaken according to different physical and chemical parameters including biological oxygen demand (BOD), Dissolved oxygen (DO), electric conductivity (EC), total suspended solids (TSS), Alkalinity, Acidity, Total hardness (TH), grease content, major cations and anions, and some heavy metals. Results showed that the Shores of the Lagos lagoon at the Iddo and C.M.S axis becomes progressively polluted by the waste materials discharged along its course. Thus, Lagoon at these locations currently faces a number of serious environmental and ecological challenges. Urbanization and high commercial activities at this axis of the Lagoon contributed to the water quality deterioration with regional consequences on the aquatic ecosystem and on the health of the down stream's user groups. This synergetic effect is of concern for the sustainable use of the resources.

The supply of water to both rural and urban centres of Nigeria is extremely poor with reference to quantity and access. The study investigated water distribution and supply in Ado-Ekiti metropolis applying a geospatial approach, with a view to generating baseline information to optimize water supply and distribution in the metropolis. Materials used included: a map of Ado-Ekiti with a scale of 1:50000 obtained from the Local Government Office, Ado-Ekiti water distribution facility map (2000) with a scale of 1:30000 obtained from the Ado-Ekiti State Water Corporation and population estimate of Ado-Ekiti from the Bureau of Statistics. Sets of structured questionnaires were used to get information from the residents and the State's Water Corporation. The study delineated existing water distribution network of the metropolis, provided (i) a map of the service areas, (ii) information on areas with distribution problems and (iii) the per capita demand of the population as inferred from the questionnaires. A lasting solution was also proffered through the design of a water distribution network for the estimated daily water demand for the years 2019 and 2049 irrespective of the variation in water needs of the residents in the area. The Geospatial approach was found to be useful in improving the distribution system through extension of pipelines and identification of various locations for service reservoirs.