Management Practices And Ecological Status Of A Humid Tropical Rainforest

This study attempts to put in perspective the spatial and floristic variations, which exist in the tropical rainforest belt of Nigeria by virtue of different management practices. The variations were examined by comparing the floristic and biomass properties of a government-managed forest with that of an adjacent community-managed forest in the same eco-climatic zone. A floristic similarity of 38.4% was observed between the two sites, while the species richness of the two sites were not significantly different, despite the different management regimes. A classification of the tree species found on both sites using Principal Component Analysis (PCA) revealed that savanna elements were gradually being introduced into the community-managed forest. However, this variation may be presumed to be temporal if forest management by rural dwellers is monitored or guided by responsible government agencies.     

Assessing the Potential for Rainwater Harvesting

Rainwater harvesting is one of the promising ways of supplementing the surface and underground scarce water resources in areas where existing water supply system is inadequate to meet demand. Rainwater harvesting is one of the measure for reducing impact of climate change on water supplies. Abeokuta has a mean annual rainfall of 1,156 mm which makes rainwater harvesting ideal. Intra annual variability lies betwen 0.7 and 1.0 while the inter annual variability was 0.2. Annually 74.0 m³ of rainwater can be harvested per household. Estimated annual water demand for flushing, laundry and flushing were 21.6 and 29.4 m³ respectively. Harvested rainwater in Abeokuta can satisfy household monthly water demand for WC flushing and laundry except for November, December, January and February. The excess rainwater stored in September and October is sufficient to supplement the short fall in the dry months provided there is adequate storage.Water savings potential is highest in June and September which is the two rainfall peak period in Southwest Nigeria.     

再生混凝土力学性能指标换算关系试验研究

在正交试验的基础上研究了在不同水胶比、再生骨料掺量、粉煤灰掺量条件下对再生混凝土的各项力学性能指标的影响,对试验结果进行了极差和方差分析,得出水胶比,再生骨料掺量和粉煤灰掺量对各指标的影响规律.在此试验基础上,引用了一些国内外再生混凝土的试验结果,采用回归分析的方法,分别建立了劈裂抗拉强度、抗折强度、弹性模量与立方体抗压强度的关系.     

Impact of El Niño and Climate Change on Rainwater Harvesting in a Caribbean State

The water situation of the Pusey district in St Catherine parish of Jamaica is acute because of the district’s hilly terrains which made connections to centralised public water supply difficult. Residents depend on rainwater harvesting (RWH) systems to meet potable needs, like many other catchments across Jamaica. Rainwater collecting practices and water use habits of the residents were surveyed and the present and future RWH capacity was evaluated using the available 18 years (1996 to 2013) rainfall data and downscaled PRECIS model A2 and B2 climate change scenarios. In addition, the effect of El Niño episodes on rainfall patterns was evaluated. The coefficients of variations for annual rainfall were found to be higher for the El Niño years than in normal years. In two of the El Niño years (1997 and 2009), rainwater harvesting capacity is negatively impacted as rainfall annual total is (42 % and 34 %) lesser than the average annual rainfall. The ability of RWH to meet potable needs in 2030s and 2050s will be reduced based on predicted shorter intense showers and frequent dry spells. A storage tank of 2.5 to 4.0 m³ per household (4 persons) is proposed to meet water demand during the maximum consecutive dry days, and January and February water shortage periods. Design of efficient RWH systems and provision of government subsidy on storage tanks will enable the residents to capture more rainwater to meet their daily domestic needs.