Browsing by Author "Iroye, K.A."
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Item EVALUATING PEAK RUNOFF HYDROGRAPHS FOR OYUN RIVER CATCHMENT IN KWARA STATE USING GIS AND REMOTE SENSING TECHNIQUES(Association of Nigerian Geographers, 2014) Rhoda Mojisola, Olanrewaju; Adedayo, I.T.; Iroye, K.A.The power of Geographic Information System and Remote Sensing techniques was used in this work, to determine the required hydrological characteristics of Oyun basin in Kwara State. Both primary and secondary data were used; the primary data are the field coordinates of prominent features in the study area while the secondary data were the administrative maps, satellite imagery, SRTM (Shuttle Radar Topographical Mission) raster data and rainfall data for the study area. The GIS techniques of data analysis used comprised of overlay operation, digital terrain modeling (DTM), spatial query operations and map calculation operations. The rainfall data was fitted using Gumbel distribution to obtain basin discharges for four selected return periods. Snyder's method was used to obtain the unit hydrograph ordinates these ordinates were used in conjunction with the discharges to generate rainfall excesses for the respective return periods while the rainfall excesses were convoluted to obtain the predicted pea k runoff (storm) hydrographs for each of the selected return periods. The outcome of this research showed that Oyun river watershed had the following hydrological characteristics; Catchment area is 827 square kilometers, main river length is about 83.57 km, length from Centroid to outlet 'is 43.24km, average basin slope is 0.01464 , the peak discharges of the basin for 5years, 25years, 50years and 100years are 129ml/s/cm, 184.4 m3/s/cm, 207.3 m'[slcm and 230 m3/s/cm, while the corresponding predicted storm hydrographs were 457.12 M3/S ,793.32 Ml/S ,941.70 M3/S and 1088.70 M3/S respectively.Item SPATIO-TEMPORAL PATTERNS OF NITRATE CONCENTRATION IN RAINWATER IN ILORIN, KWARA STATE NIGERIA(FACULTY OF MANAGEMENT SCIENCES, UNIVERSITY OF ILORIN, 2014) Iroye, K.A.; Rhoda Mojisola, Olanrewaju; Oyelakin, R.I.This study examined the spatio-temporal pattern of nitrate concentration in rainwater in florin, Kwara State, Nigeria. Thirty five rainwater samples were collectedfrom each of the five different land-uses using sterilized 75 centiliters plastic bottles on event basis between the onset and cessation of rainfall (March 4'1. - October 24,h, 2013) in the study area. The collected water samples were subsequently analyzedfor nitrate concentration in University of florin Chemistry laboratory using sodium salicylate (colorimetric) method. Result obtained indicates high variability in both spatial and temporal patterns of nitrate concentration in the study area. While the temporal pattern revealed high concentrations in the months of March, April, July and September; Oja-Oba, Asa Dam and Oke-Oyi areas of the city exhibits high degree of concentrations in that order spatially. Likely reasons for the observed pattern of concentrations were discussed while suggestions towards reducing the rate of pollution to biologically safe levels were presented.