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Frequent reports of haematuria among resettlers at Ibaro and Abule-titun located close to a newly constructed reservoir. 20 km north-west of Abeokuta. Ogun State, Nigeria. prompted a pre-control survey to assess age and sex distribution of urinary schistosomiasis in the communities. 210 persons were examined at Ibaro and 145 at Abule-titun between April 1988 and February 1989. Overall prevalence was about 80% in both villages, and all age and sex groups examined were affected. The pattern of infection in both villages was similar, prevalence being high in all age and sex groups and, unlike most endemic communities, the rate of infection was not significantly higher among the 5–14 year age groups. Intensity of infection was also high in all age and sex groups with mean range egg output of between 73±73 and 2016±3875 ova/10ml urine at Ibaro and between 231±122 and 1340±1786 ova/10ml urine at Abule-titun. This is attributed to an occupation-related high rate of human water contact in both villages.

In this study, three streams-Amuta, Agbogbo and Abagbooro were examined for salinity and sodium hazards and suitability of the water for irrigational purpose. The three streams are located within areas of three different agricultural practices and land uses. Water samples from the streams were collected twice a month for 1 year. Irrigation water quality parameters assessed included pH, electrical conductivity (EC), sodium adsorption ratio (SAR), percentage sodium, permeability index and potential salinity. Water samples were analyzed using standard chemical procedures. Results of the irrigation water quality parameters studied showed that water samples from the three streams do not exhibit toxicity problem in relation to salinity and sodium hazard. Although the data obtained for the three catchment areas for pH, EC and SAR were closely related, least concentrations of these irrigation water indices were obtained for Abagbooro stream where there is secondary forest; highest concentrations were found in Agbogbo stream and moderate values were obtained for water from Amuta stream where subsistent and mechanized farming are practiced, respectively.

The twocomponent hydrograph separation method has been used to investigate the sources of storm runofl at Allt a Mharcaidh during storms

The suspended sediment concentration response of three small streams draining quartzites and quartz-schists in southwestern Nigeria to storms of varying magnitude are presented. A total of 1468 water samples from 62 storm responses with peak stream discharge values ranging from 80 to 120 I s-' were analysed and storm and suspended sediment concentration hydrographs and hysteresis loops were used to depict the response patterns. The six different types of responses identified include the single and multiple discharge peak rises with sediment lead and lag and also the mixed response patterns. Both valley slope and channel erosion constituted important sources of suspended sediment. However, sediment availability, exhaustion, and flushing effects determined the variation in the different response types.

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