Browsing by Author "Maliondo, S. M.S."
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Item Characterization of soil depth to coral bedrock and bedrock roughness in Jozani Groundwater Forest, Zanzibar, Tanzania.(International Journal of Scientific & Engineering Research, 2017) Said, M. S.; Msanya, B. M.; Semoka, J. R.; Maliondo, S. M.S.Soils formed on coral terrain have a wide range of depths to coral bedrock and percentage of coral outcrops. Cliffs and other featuresof seawater abrasion, limited root zone, habitation and distribution of specific plant species are among the common conditions on Zanzibar coral landscapes.The current study was intended to characterize the relationship between soil depth to coral bedrock (SDCB) and bedrock roughness (BR) and determine features which are related to seawater abrasion at Jozani Groundwater Forest (JGWF). Such conditions and features have varying spatial distribution and magnitude which are likely to affect plant growth and species distribution in JGWF. The study area was divided into 320 grid points that were used as probing points for determining SDCB and BR. Global positioning system (GPS) model GARMIN etrex 10 was used to locate grid points, while a long graduated stick was used to measure depths from soil surface to coral bedrock at each point. SDCB was calculated as an arithmetic mean of measured depths and BR as standard deviation of measured depths. ArcGIS 10.1 was used to map SDCB and BR of JGWF. Kichangani in Tumbatu Islet was visited to gather information related to abrasion that took place on coastal coral bedrock. Minimum values of SDCB and BR obtained from JGWF grassland were used to rank and categorize SDCB and BR in JGWF. Results from probes on the 302 grid points showed that JGWF has range of SDCB of about 0.35 - 1.4 m and above (>1.4 m) and BR of 0.1 - 0.4 m and above (>0.4 m).Trends of SDCB and BR values in JGWF were complex, decreasing towards the cliff on the West and towards North-end, but increased in the opposite direction. It was concluded from this study that there are complex relationships between SDCB and BR on coral land and that the relationships can be captured, ranked, and mapped. Such relationships affect plant growth and species distribution. Again, flat platform which was found at Kichangani and grassland of JGWF is an evidence of seawater abrasion on coral bedrocks.Item Extent of seawater intrusion from Chwaka and Uzi bays into Jozani Groundwater Forest, Zanzibar, Tanzania.(International Journal of Scientific & Engineering Research,, 2017) Said, M. S.; Maliondo, S. M.S.; Semoka, J. M. R.; Msanya, B. M.The rise in the total dissolved solids (TDS) in a coastal land is among the signs of seawater intrusion into the land. In many cases, the magnitude of the effects of seawater intrusion depends upon the proximity of the land to the coast, amount, and patterns of freshwater recharging the aquifer underneath. The intention of this study was to determine the extent to which Jozani groundwater forest (JGWF) has been affected by seawater intrusion from Chwaka and Uzi bays. Rainfall data were collected from Tanzania Meteorological Agency (TMA). Spatial and temporal TDS values were collected from temporary wells (TWs) and local wells. Desk work divided JGWF length into 11 northern and 4 eastern gridlines. Along northern gridlines, three grid points were selected on which TWs were drilled for data collection. GARMIN etrex 10 GPS was used for geo-referencing the wells. Water samples were collected at about 0.1 m depth from water surface and were tested in situ using Hanna Combo HI 98129 tester. Water tests were done in the middle of Kiangazi, Masika, Kipupwe and Vuli seasons. The area of JGWF was estimated based on JGWF elevation map. The results showed that the average TDS values in JGWF ranged from 0.4 - 25 x 103 mg L-1. The least TDS values were recorded from the inner parts of JGWF while highest TDS values were recorded from the outmost parts. It was found that rainfall patterns: rainy and dry seasons affected TDS values and their spatial trends. The TDS severity in JGWF area was assigned five categories namely none: least-, slightly-, moderately- and severely-affected areas. The range of TDS values for these categories were 0 – 0.5, 0.5 – 2, 2 - 5, 5 - 10 and >10 x 103 mg L-1 and the areas of occupation were about 342.3 ha (58.2%), 61.8 ha (10.5%), 46.8 ha (8.0%), 47.4 ha (8.1%) and 89.4 ha (15.2%), respectively. In conclusion, it was found that about 77% of JGWF is free from intrusion effects, but there were some variations of TDS values between dry and rainy seasons that also in the long run cause TDS fluctuation between years