Tidal Trends and Magnitude of Chwaka and Uzi Bays as a Proxy of Seawater Intrusion in Jozani Groundwater Forest, Zanzibar, Tanzania

Masoud Salum Said; Balthazar Michael Msanya; Johnson Mashambo Semoka; Salim Mohamed Salim Maliondo

doi:doi:10.11648/j.ajaf.20160406.15

| Peer-Reviewed

Tidal Trends and Magnitude of Chwaka and Uzi Bays as a Proxy of Seawater Intrusion in Jozani Groundwater Forest, Zanzibar, Tanzania

Masoud Salum Said, Balthazar Michael Msanya, Johnson Mashambo Semoka, Salim Mohamed Salim Maliondo

Published in American Journal of Agriculture and Forestry (Volume 4, Issue 6)

Received: 14 December 2016 Accepted: 4 January 2017 Published: 2 February 2017

Views: Downloads:

Download PDF

Share This Article

Twitter
Linked In
Facebook

Abstract

Tidal characteristics, land altitude, level of groundwater, and rainfall patterns are among the main factors determining seawater intrusions in coastal areas. As Jozani Groundwater Forest (JGWF) is a coastal forest of low altitude found between Chwaka and Uzi bays, it was assumed the forest is increasingly being intruded by seawater. This study was therefore intended to discern conditions of tidal trends and magnitude in relation to seawater intrusion into JGWF. Tidal data and rainfall patterns were collected from Tanzania Meteorological Agency, Kisauni Zanzibar. Two sets of three observation wells (OWs) were opened at two forest ends towards Chwaka and Uzi bays. The OWs were used as data collection points while Height of Instrument method with the help of SOKKIA C.3.2 level and benchmarks number 205 and 210 were used to determine elevation of ground surfaces of the OWs. GPS receiver model GARMIN etrex 10 was used for geo-referencing the OWs. Water level recorders were installed above the wells to record changes in water level (WL) around the wells. Total dissolved solids (TDS) in water samples from the OWs were measured in situ using Hanna Combo tester HI 98129. Results showed that WL in South-end OWs rises during rains and falls during dry seasons, and occasionally also rises during high water of spring tide (HWST) associated with South Easterly monsoon winds. Similar results were obtained at North-end OWs, but more frequently even during HWST that were not associated with Monsoon winds. Values of water TDS fell to a minimum of 0.7 x 10³ and 4.9 x 10³ ppm during rainfall and rose to a maximum of 25.5 x 10³ and 34.1 x 10³ ppm during dry season at South-end and North-end, respectively. It was concluded that intrusion takes place during dry seasons when seawater of HWST from Chwaka and Uzi bays through creeks reached the soil surfaces at North-end and South-end of JGWF. The water accumulated salts which were then diluted and drained off the areas by rain water.

Published in	American Journal of Agriculture and Forestry (Volume 4, Issue 6)
DOI	10.11648/j.ajaf.20160406.15
Page(s)	168-177
Creative Commons	This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.
Copyright	Copyright © The Author(s), 2017. Published by Science Publishing Group

Keywords

Seawater Tide, Surface Level, Water Level, Total Dissolved Solids, Intrusion, Draining

References

[1]	Werner, A. D. and Simmons, C. T. (2009). Impact of sea‐level rise on sea water intrusion in coastal aquifers. Ground Water 47 (2): 197-204.
[2]	Kuan, W. K., Jin, G., Xin, P., Robinson, C., Gibbes, B. and Li, L. (2012). Tidal influence on seawater intrusion in unconfined coastal aquifers. Water Resources Research 48 (2) W02502, doi:10.1029/2011WR010678.(accessed 25/08/2014).
[3]	Vice President’s Office (VPO) (2012). National Climate Change Strategy. Division of Environment, United Republic of Tanzania. 92pp.
[4]	Nowak Katarzyna, and Phyllis C. Lee (2011). Demographic structure of Zanzibar red colobus populations in unprotected coral rag and mangrove forests. International Journal of Primatology 32 (1): 24-45.
[5]	Zanzibar Revolutionary Government (ZRG) (2013). Zanzibar Woody Biomass Survey Preparedness for REDD+ Phase: Biophysical Inventory Report. Using Zanzibar Woody Biomass Survey in Policy and Planning Processes, Working Paper. Indofood (Forest Intelligence) and Norwegian Embassy, Zanzibar, Tanzania. 24pp.
[6]	Klein, R. (2008). An edaphic landscape of Unguja Island, Zanzibar. Exploratory study on the relation between soil variability and landscape. Dissertation for Award of MSc Degree Turku University, Finland. 85 pp.
[7]	Leonola, B. S. (2011). Assessing the spatial and temporal characteristics of ground water recharge in Zanzibar. Dissertation for Award of MSc. Degree at University of Twente, Enschede, Netherland. 46pp.
[8]	Nhnyete, I. K. and Mahongo, S. B. (2007). National Report of the United Republic of Tanzania on sea level measurements. [http://www.gloss-sealevel.org/publications/documents/tanzania_gex2007.pdf] (accessed 25/07/2014).
[9]	ASCLME (2012). National Marine Ecosystem Diagnostic Analysis, Tanzania. Contribution to the Agulhas and Somali Current Large Marine Ecosystems Project (supported by UNDP with GEF grant financing). Unpublished report. 92pp.
[10]	Robinson, C., Gibbes, B., Carrey H. and Li, L. (2007). Salt‐freshwater dynamics in a subterranean estuary over a spring‐neap tidal cycle. Journal of Geophysical Research: Oceans 112 (C9): 1-15.
[11]	Semesi, A. K. (2013). Developing management plans for the mangrove forest reserves: The Ecology of Mangrove and Related Ecosystems: In: Proceedings of the International Symposium. Edited by Springer Science & Business Media 80. 24–30 September 1990 Mombasa, Kenya, 1-10pp.
[12]	Van Camp, M., Mtoni, Y., Mjemah, I. C., Bakundukize, C. and Walraevens, K. (2014). Investigating seawater intrusion due to groundwater pumping with schematic model simulations. The example of the Dar es Salaam coastal aquifer in Tanzania. Journal of African Earth Sciences 96: 71-78.
[13]	Guo, H. and Jiao, J. J. (2007). Impact of coastal land reclamation on ground water level and the sea water interface. Ground Water 45 (3): 362-367.
[14]	Salum, L. M. (2009). Ecotourism and biodiversity conservation in Jozani-Chwaka Bay National Park, Zanzibar. Africa Journal of Ecology 47: 166-170.
[15]	Humphrey, C. P., Harris, J. and O'Driscoll, M. A. (2012). Evaluation of Water Table Dynamics in Relation to Soil Morphological Indicators of Seasonal Wetness. Universal Journal of Environmental Research and Technology 2 (4): 286-292.
[16]	Majolagbe, A. O., Adeyi, A. and Osibanjo, O. (2014). Hydrochemical characterization and quality assessment of groundwater in the vicinities of a major active dumpsite in Lagos, Nigeria: the use of multivariate analytical technique and water quality indices. Europe Water48: 29-42.
[17]	Emmanuel, B. E. and Chukwu, L. O. (2010). Spatial distribution of saline water and possible sources of intrusion into a tropical freshwater lagoon and the transitional effects on the lacustrine ichthyofaunal diversity. African Journal of Environmental Science and Technology 4 (7): 480-491.
[18]	Shahba, M. A., Alshammary, S. F. and Abbas, M. S. (2012). Effects of salinity on seashore Paspalum cultivars at different mowing heights. Crop science 52 (3): 1358-1370.
[19]	Philippa, A., Marc E., Carl H., Shirley H., Rebecca L., Russel S., David S. and Anna V. (2003). Coastal aquifer saltwater intrusion assessment guidelines. Environment Canterbury Technical Report No. R04/18. 47pp.
[20]	SaMeH (2014). A precise methodology integrates low-cost GPS data and GIS for monitoring groundwater quality parameters in Majmaah region, KSA, International Journal of Environmental Monitoring and Analysis 2 (5): 279-288.
[21]	Brinker, R. C. and Minnick, R. (Eds.) (2012). The surveying handbook. Springer Science & Business Media. 971pp.
[22]	Slama, F. (2010). Field experimentation and modelling of salt transfer in Korba coastal plain: Impact of seawater intrusion and irrigation practices. Doctoral dissertation, University of Neuchâtel. 138pp.
[23]	Masoud, S. S., Msanya, B. M., Semoka, J. M. R. and Maliondo, S. M. S. (2016). Use of water table as a benchmark for levelling groundwater forest: The case of Jozani Groundwater Forest, Zanzibar, Tanzania. International Journal of Scientific and Technical Research in Engineering (IJSTRE) 1 (5): 49-57.
[24]	Heiss, J. W. and Michael, H. A. (2014). Saltwater‐freshwater mixing dynamics in a sandy beach aquifer over tidal, spring‐neap, and seasonal cycles. Water Resources Research 50 (8): 6747-6766.

Cite This Article

Plain Text BibTeX RIS

APA Style

Masoud Salum Said, Balthazar Michael Msanya, Johnson Mashambo Semoka, Salim Mohamed Salim Maliondo. (2017). Tidal Trends and Magnitude of Chwaka and Uzi Bays as a Proxy of Seawater Intrusion in Jozani Groundwater Forest, Zanzibar, Tanzania. American Journal of Agriculture and Forestry, 4(6), 168-177. https://doi.org/10.11648/j.ajaf.20160406.15

Copy | Download

ACS Style

Masoud Salum Said; Balthazar Michael Msanya; Johnson Mashambo Semoka; Salim Mohamed Salim Maliondo. Tidal Trends and Magnitude of Chwaka and Uzi Bays as a Proxy of Seawater Intrusion in Jozani Groundwater Forest, Zanzibar, Tanzania. Am. J. Agric. For. 2017, 4(6), 168-177. doi: 10.11648/j.ajaf.20160406.15

Copy | Download

AMA Style

Masoud Salum Said, Balthazar Michael Msanya, Johnson Mashambo Semoka, Salim Mohamed Salim Maliondo. Tidal Trends and Magnitude of Chwaka and Uzi Bays as a Proxy of Seawater Intrusion in Jozani Groundwater Forest, Zanzibar, Tanzania. Am J Agric For. 2017;4(6):168-177. doi: 10.11648/j.ajaf.20160406.15

Copy | Download

@article{10.11648/j.ajaf.20160406.15,
  author = {Masoud Salum Said and Balthazar Michael Msanya and Johnson Mashambo Semoka and Salim Mohamed Salim Maliondo},
  title = {Tidal Trends and Magnitude of Chwaka and Uzi Bays as a Proxy of Seawater Intrusion in Jozani Groundwater Forest, Zanzibar, Tanzania},
  journal = {American Journal of Agriculture and Forestry},
  volume = {4},
  number = {6},
  pages = {168-177},
  doi = {10.11648/j.ajaf.20160406.15},
  url = {https://doi.org/10.11648/j.ajaf.20160406.15},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ajaf.20160406.15},
  abstract = {Tidal characteristics, land altitude, level of groundwater, and rainfall patterns are among the main factors determining seawater intrusions in coastal areas. As Jozani Groundwater Forest (JGWF) is a coastal forest of low altitude found between Chwaka and Uzi bays, it was assumed the forest is increasingly being intruded by seawater. This study was therefore intended to discern conditions of tidal trends and magnitude in relation to seawater intrusion into JGWF. Tidal data and rainfall patterns were collected from Tanzania Meteorological Agency, Kisauni Zanzibar. Two sets of three observation wells (OWs) were opened at two forest ends towards Chwaka and Uzi bays. The OWs were used as data collection points while Height of Instrument method with the help of SOKKIA C.3.2 level and benchmarks number 205 and 210 were used to determine elevation of ground surfaces of the OWs. GPS receiver model GARMIN etrex 10 was used for geo-referencing the OWs. Water level recorders were installed above the wells to record changes in water level (WL) around the wells. Total dissolved solids (TDS) in water samples from the OWs were measured in situ using Hanna Combo tester HI 98129. Results showed that WL in South-end OWs rises during rains and falls during dry seasons, and occasionally also rises during high water of spring tide (HWST) associated with South Easterly monsoon winds. Similar results were obtained at North-end OWs, but more frequently even during HWST that were not associated with Monsoon winds. Values of water TDS fell to a minimum of 0.7 x 103 and 4.9 x 103 ppm during rainfall and rose to a maximum of 25.5 x 103 and 34.1 x 103 ppm during dry season at South-end and North-end, respectively. It was concluded that intrusion takes place during dry seasons when seawater of HWST from Chwaka and Uzi bays through creeks reached the soil surfaces at North-end and South-end of JGWF. The water accumulated salts which were then diluted and drained off the areas by rain water.},
 year = {2017}
}

Copy | Download

TY  - JOUR
T1  - Tidal Trends and Magnitude of Chwaka and Uzi Bays as a Proxy of Seawater Intrusion in Jozani Groundwater Forest, Zanzibar, Tanzania
AU  - Masoud Salum Said
AU  - Balthazar Michael Msanya
AU  - Johnson Mashambo Semoka
AU  - Salim Mohamed Salim Maliondo
Y1  - 2017/02/02
PY  - 2017
N1  - https://doi.org/10.11648/j.ajaf.20160406.15
DO  - 10.11648/j.ajaf.20160406.15
T2  - American Journal of Agriculture and Forestry
JF  - American Journal of Agriculture and Forestry
JO  - American Journal of Agriculture and Forestry
SP  - 168
EP  - 177
PB  - Science Publishing Group
SN  - 2330-8591
UR  - https://doi.org/10.11648/j.ajaf.20160406.15
AB  - Tidal characteristics, land altitude, level of groundwater, and rainfall patterns are among the main factors determining seawater intrusions in coastal areas. As Jozani Groundwater Forest (JGWF) is a coastal forest of low altitude found between Chwaka and Uzi bays, it was assumed the forest is increasingly being intruded by seawater. This study was therefore intended to discern conditions of tidal trends and magnitude in relation to seawater intrusion into JGWF. Tidal data and rainfall patterns were collected from Tanzania Meteorological Agency, Kisauni Zanzibar. Two sets of three observation wells (OWs) were opened at two forest ends towards Chwaka and Uzi bays. The OWs were used as data collection points while Height of Instrument method with the help of SOKKIA C.3.2 level and benchmarks number 205 and 210 were used to determine elevation of ground surfaces of the OWs. GPS receiver model GARMIN etrex 10 was used for geo-referencing the OWs. Water level recorders were installed above the wells to record changes in water level (WL) around the wells. Total dissolved solids (TDS) in water samples from the OWs were measured in situ using Hanna Combo tester HI 98129. Results showed that WL in South-end OWs rises during rains and falls during dry seasons, and occasionally also rises during high water of spring tide (HWST) associated with South Easterly monsoon winds. Similar results were obtained at North-end OWs, but more frequently even during HWST that were not associated with Monsoon winds. Values of water TDS fell to a minimum of 0.7 x 103 and 4.9 x 103 ppm during rainfall and rose to a maximum of 25.5 x 103 and 34.1 x 103 ppm during dry season at South-end and North-end, respectively. It was concluded that intrusion takes place during dry seasons when seawater of HWST from Chwaka and Uzi bays through creeks reached the soil surfaces at North-end and South-end of JGWF. The water accumulated salts which were then diluted and drained off the areas by rain water.
VL  - 4
IS  - 6
ER  -

Copy | Download

Author Information

Masoud Salum Said

Department of Soil and Geological Sciences, College of Agriculture, Sokoine University of Agriculture, Morogoro, Tanzania
Balthazar Michael Msanya

Department of Soil and Geological Sciences, College of Agriculture, Sokoine University of Agriculture, Morogoro, Tanzania
Johnson Mashambo Semoka

Department of Soil and Geological Sciences, College of Agriculture, Sokoine University of Agriculture, Morogoro, Tanzania
Salim Mohamed Salim Maliondo

Department of Ecosystems and Conservation, College of Forestry, Wildlife and Tourism, Sokoine University of Agriculture, Morogoro, Tanzania

Download PDF

Sections

Plain Text BibTeX RIS

APA Style

Masoud Salum Said, Balthazar Michael Msanya, Johnson Mashambo Semoka, Salim Mohamed Salim Maliondo. (2017). Tidal Trends and Magnitude of Chwaka and Uzi Bays as a Proxy of Seawater Intrusion in Jozani Groundwater Forest, Zanzibar, Tanzania. American Journal of Agriculture and Forestry, 4(6), 168-177. https://doi.org/10.11648/j.ajaf.20160406.15

Copy | Download

ACS Style

Masoud Salum Said; Balthazar Michael Msanya; Johnson Mashambo Semoka; Salim Mohamed Salim Maliondo. Tidal Trends and Magnitude of Chwaka and Uzi Bays as a Proxy of Seawater Intrusion in Jozani Groundwater Forest, Zanzibar, Tanzania. Am. J. Agric. For. 2017, 4(6), 168-177. doi: 10.11648/j.ajaf.20160406.15

Copy | Download

AMA Style

Masoud Salum Said, Balthazar Michael Msanya, Johnson Mashambo Semoka, Salim Mohamed Salim Maliondo. Tidal Trends and Magnitude of Chwaka and Uzi Bays as a Proxy of Seawater Intrusion in Jozani Groundwater Forest, Zanzibar, Tanzania. Am J Agric For. 2017;4(6):168-177. doi: 10.11648/j.ajaf.20160406.15

Copy | Download

@article{10.11648/j.ajaf.20160406.15,
  author = {Masoud Salum Said and Balthazar Michael Msanya and Johnson Mashambo Semoka and Salim Mohamed Salim Maliondo},
  title = {Tidal Trends and Magnitude of Chwaka and Uzi Bays as a Proxy of Seawater Intrusion in Jozani Groundwater Forest, Zanzibar, Tanzania},
  journal = {American Journal of Agriculture and Forestry},
  volume = {4},
  number = {6},
  pages = {168-177},
  doi = {10.11648/j.ajaf.20160406.15},
  url = {https://doi.org/10.11648/j.ajaf.20160406.15},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ajaf.20160406.15},
  abstract = {Tidal characteristics, land altitude, level of groundwater, and rainfall patterns are among the main factors determining seawater intrusions in coastal areas. As Jozani Groundwater Forest (JGWF) is a coastal forest of low altitude found between Chwaka and Uzi bays, it was assumed the forest is increasingly being intruded by seawater. This study was therefore intended to discern conditions of tidal trends and magnitude in relation to seawater intrusion into JGWF. Tidal data and rainfall patterns were collected from Tanzania Meteorological Agency, Kisauni Zanzibar. Two sets of three observation wells (OWs) were opened at two forest ends towards Chwaka and Uzi bays. The OWs were used as data collection points while Height of Instrument method with the help of SOKKIA C.3.2 level and benchmarks number 205 and 210 were used to determine elevation of ground surfaces of the OWs. GPS receiver model GARMIN etrex 10 was used for geo-referencing the OWs. Water level recorders were installed above the wells to record changes in water level (WL) around the wells. Total dissolved solids (TDS) in water samples from the OWs were measured in situ using Hanna Combo tester HI 98129. Results showed that WL in South-end OWs rises during rains and falls during dry seasons, and occasionally also rises during high water of spring tide (HWST) associated with South Easterly monsoon winds. Similar results were obtained at North-end OWs, but more frequently even during HWST that were not associated with Monsoon winds. Values of water TDS fell to a minimum of 0.7 x 103 and 4.9 x 103 ppm during rainfall and rose to a maximum of 25.5 x 103 and 34.1 x 103 ppm during dry season at South-end and North-end, respectively. It was concluded that intrusion takes place during dry seasons when seawater of HWST from Chwaka and Uzi bays through creeks reached the soil surfaces at North-end and South-end of JGWF. The water accumulated salts which were then diluted and drained off the areas by rain water.},
 year = {2017}
}

Copy | Download

TY  - JOUR
T1  - Tidal Trends and Magnitude of Chwaka and Uzi Bays as a Proxy of Seawater Intrusion in Jozani Groundwater Forest, Zanzibar, Tanzania
AU  - Masoud Salum Said
AU  - Balthazar Michael Msanya
AU  - Johnson Mashambo Semoka
AU  - Salim Mohamed Salim Maliondo
Y1  - 2017/02/02
PY  - 2017
N1  - https://doi.org/10.11648/j.ajaf.20160406.15
DO  - 10.11648/j.ajaf.20160406.15
T2  - American Journal of Agriculture and Forestry
JF  - American Journal of Agriculture and Forestry
JO  - American Journal of Agriculture and Forestry
SP  - 168
EP  - 177
PB  - Science Publishing Group
SN  - 2330-8591
UR  - https://doi.org/10.11648/j.ajaf.20160406.15
AB  - Tidal characteristics, land altitude, level of groundwater, and rainfall patterns are among the main factors determining seawater intrusions in coastal areas. As Jozani Groundwater Forest (JGWF) is a coastal forest of low altitude found between Chwaka and Uzi bays, it was assumed the forest is increasingly being intruded by seawater. This study was therefore intended to discern conditions of tidal trends and magnitude in relation to seawater intrusion into JGWF. Tidal data and rainfall patterns were collected from Tanzania Meteorological Agency, Kisauni Zanzibar. Two sets of three observation wells (OWs) were opened at two forest ends towards Chwaka and Uzi bays. The OWs were used as data collection points while Height of Instrument method with the help of SOKKIA C.3.2 level and benchmarks number 205 and 210 were used to determine elevation of ground surfaces of the OWs. GPS receiver model GARMIN etrex 10 was used for geo-referencing the OWs. Water level recorders were installed above the wells to record changes in water level (WL) around the wells. Total dissolved solids (TDS) in water samples from the OWs were measured in situ using Hanna Combo tester HI 98129. Results showed that WL in South-end OWs rises during rains and falls during dry seasons, and occasionally also rises during high water of spring tide (HWST) associated with South Easterly monsoon winds. Similar results were obtained at North-end OWs, but more frequently even during HWST that were not associated with Monsoon winds. Values of water TDS fell to a minimum of 0.7 x 103 and 4.9 x 103 ppm during rainfall and rose to a maximum of 25.5 x 103 and 34.1 x 103 ppm during dry season at South-end and North-end, respectively. It was concluded that intrusion takes place during dry seasons when seawater of HWST from Chwaka and Uzi bays through creeks reached the soil surfaces at North-end and South-end of JGWF. The water accumulated salts which were then diluted and drained off the areas by rain water.
VL  - 4
IS  - 6
ER  -

Copy | Download