Variation of interception loss with different plant species at the University of Agriculture, Abeokuta, Nigeria

Interception studies of six plants groups were carried out at the campus of University of Agriculture, Abeokuta in Nigeria, using three different sample sites. These sites were the Arborea plantation, cashew plantation and College of Environmental Resources Management premises of the University. The field work was carried out between 15th June and 28th September, 2009. Of the 22 rainfall events recorded for each plant species, at least 13 produced measurable through fall and stem flow and a maximum of 18 measurable records. Through fall showed a very strong linear correlation against daily rainfall for different plant species. The r2 values varied between 0.841 (Teak) to 0.963 (Gmelina). This trend also followed for stem flow since without rainfall no stem flow. This was not the case for interception loss which showed only a moderate correlation against rainfall amount for each plant species with r2 value ranging from 0.058 (Teak) to 0.716 (Neem). This implied an inverse relationship between interception rate and rainfall amount. Interception ratio for coniferous plants was more than deciduous plants, both having average values of 32.01 and 26.54% respectively when interception loss was considered per storm or event. But when considered at the end of observation, deciduous plants had more interception ratio than the coniferous plants with average interception values of 26.54 and 32.01% respectively. At the end of the observation, the interception loss for each plant, Pinus leuceana sp, cashew, Neem, Gmelina and Teak were 18.77, 21.04, 31.96, 26.16, 11.1 and 38.05% respectively. The values changed when considering average interception loss per storm and the values for the plants species as arranged above were 28.60, 30.18, 31.96, 37.26, 17.78 and 29.89% respectively. This showed that interception loss varied from one plant species to another. With these, one will know which can best be used for conservation purpose.Key words: Through fall, stem flow, canopy

Possible Abstraction Sites along Osun River Lower Course in Ogun and Lagos State, Nigeria For Sustainable Supply Of Potable Water

Water scarcity remains a major challenge in all the developing nations of the world; not because of paucity of surface water (rivers and streams) that could be abstracted for treatment, but, finding a suitable and sustainable abstraction site. The main objective of this research is to identify good locations, where water treatment plant could be sited along Osun River in Ogun and Lagos State for sustainable production of potable water. To achieve this, water quality of Osun River upstream Lekki lagoon was investigated at three sampling stations; Ogbere, Igbonla and Lekki. Water parameters such as physical (temperature, solids, turbidity) chemicals (pH, electrical conductivity (EC), dissolved oxygen (DO), chemical oxygen demand (COD), nitrate, phosphate, chloride and sulphate, alkalinity, potassium, lead, chromium, iron) and bacteriological (feacal coliform) were determined using standard procedures. The results revealed that Ogbere and Igbonla stations are better locations where water could be abstracted from Osun River than Lekki stations due to low measured parameters (indicators of water pollution), which were within World Health Organization (WHO) acceptable limits. The findings also showed that while raw water abstraction from Osun River at Ogbere and Igbonla stations would require a conventional treatment, raw water from the Lekki lagoon (station) would require special treatment especially desalination due to high chloride and EC contents with expected cost implication

Assessment of Nutrient Concentration in Sokori River, Southwest Nigeria

Water management planners are facing considerable uncertainties on future demand and availability of  water partly due to concentration of nutrient leading to excessive unsightly growth of aquatic plants and  algal bloom in rivers. This study was carried out to assess the trend of nutrient concentration in Sokori  stream in Southwest Nigeria. The selected nutrients determined in the stream were nitrate, sulphate and phosphate, dissolved oxygen and biological oxygen demand. Water samples from 10 sampling point at  100m interval were examined to assess the variation in concentration of nutrients along the stream using  standard method. Descriptive statistics was used in data analysis. The result showed that high nutrient concentrations were established at the middle section of the stream. It is obvious that sulphate has the highest concentration (3.60 Mg/l), followed by phosphate (2.13 Mg/l) then nitrate (0.89 Mg/l). However, the nutrient concentrations in the stream were below the acceptable limit set by the World Health  Organization. Furthermore, it was observed that where the nutrients concentration (PO4 = 5.16 Mg/l, SO4,= 9.78 Mg/l, NO2 = 1.46 Mg/l) and the BOD (10.24 Mg/l) were highest at the mid – section of stream, while the DO concentration (3.63 Mg/l)  lowest indicating concentrated aquatic life (macro and micro-organisms) activity. Nutrient enrichment leads to excessive growth of primary producers as well  as  heterotrophic bacteria and fungi, which increases the metabolic activities of stream water leading to a depletion of dissolved oxygen. The low discharge of stream  and its fairly flat terrain nature also influenced the metabolic activities in the mid- section of the stream although there was no evidence of accumulation of nutrient leading to eutrophication risk.Keywords: Nutrients, Sokori stream, Phosphate, Nitrate, Sulphate, Runof

An assessment of the effect of industrial pollution on Ibese River, Lagos, Nigeria

This paper deals with pollution aspect of environmental management and monitoring of the river for its sustainable development. The water quality assessment of Ibese River, which is the principal river of the Igbogbo Abayeku Areas of Ikorodu in Lagos, was performed. Assessment was undertaken according to different physical and chemical parameters including biological oxygen demand (BOD), dissolved oxygen (DO), electric conductivity (EC), total dissolved solids (TDS), alkalinity, acidity, total hardness (TH), grease content, major cation and anion, and some heavy metals. Results showed that the river, which was of good water quality at its upstream, in terms of the aforementioned parameters, becomes progressively polluted by the waste materials discharged along its course. A general downstream trend of increase in organic and inorganic pollution was declared. Thus, Ibese River currently faces a number of serious environmental and ecological challenges. Urbanization and industrialization of the watershed at Ibese area in Ikorodu contributed to the water quality deterioration with regional consequences on the aquatic ecosystem and on the health of the downstream’s user groups. This synergetic effect is of concern for the sustainable use of the resources.Key words: Nigeria, Ibese River, water pollution, major cation and anion, heavy metals, water quality deterioration