Open Access Original Research Article

Prioritization of Flash Flood-Prone Areas in Small Coastal Basins around the Mediterranean Using Geomorphological Variables

V. A. Kotinas

Journal of Geography, Environment and Earth Science International, Page 1-11
DOI: 10.9734/jgeesi/2021/v25i630289

The present study aims to model flash flood risk in small coastal watersheds in areas that are characterized by Mediterranean climate through extensive morphometric analysis which can prove invaluable for the investigation of flood risk, in ungauged watersheds, where flash floods are frequent. The available topographic data (EU-DEM) are analyzed through Geographic Information Systems (GIS) to produce all the secondary variables that are necessary for this morphometric analysis. Watershed prioritization techniques that are applied on geomorphological variables have proven to be an effective way of estimating the relative flash flood risk in a sub-watershed level. A series of morphometric parameters are used (bifurcation ratio, drainage frequency, drainage density, drainage texture, length of overland flow, circularity ratio, form factor, elongation ratio) which have an effect on flood risk. In small watersheds, with intermittent runoff, this effect can be different than in larger watersheds, so our methodology differs significantly from the methodology other researchers use. The compound factor is calculated by aggregating the assigned ranks of these morphometric indices and the sub-watersheds are prioritized according to their flash flood risk. The study area is located in the island of Samos, in Eastern Greece, where flood events are usual and pose a risk to villages and infrastructure around the island. The selected watershed (Imvrasos river) is divided into several sub-watersheds (W-1 to W-8) and a series of morphometric indices are calculated and evaluated through statistical procedures and by applying prioritization techniques, in order to locate the sub-basins that have the highest risk to flash floods. Sub-watersheds W-2 and W-3 (on the southern part of Imvrasos area) show the highest prioritization values, and should be prioritized for better watershed management planning.

Open Access Original Research Article

Potable Water Scarcity and Options for Effective Provision in Limbe Municipality, Southwest Region, Cameroon

Emmanuel Nong Buh, Roy Lyonga Mbua, Ukah Bonaventure Ngong

Journal of Geography, Environment and Earth Science International, Page 12-21
DOI: 10.9734/jgeesi/2021/v25i630290

Continuous potable water scarcities in Limbe municipality if not well manage and ensure a regular provision of it may lead to many disastrous consequences to the massive growing population of this municipality. Lack of safe drinking water is a severe crisis in Limbe and Cameroon due to poor management strategies employed by the water management bodies involved. The study investigated the implications of water scarcity in Limbe municipality and the options for effective provision of potable water. A questionnaire survey was carried out. About 300 questionnaires were administered in three localities of Limbe to investigate the present status of water scarcity and its impacts on the local communities. The results show an increasing rate of potable water scarcity in the municipality. About 51% of the respondents indicated that inadequate storage facilities are the main caused of water scarcity in the town. In contrast, 26% and 23% of the respondents indicated that inadequate technology and low level of education are other reasons contributing to potable water scarcity in Limbe municipality. Many people in the municipality depend on untreated water sources, resulting in the contraction of many diseases like dysentery and diarrhea as prime waterborne health risks. We suggest options like installing large water safety tanks in all the localities of Limbe municipality. Furthermore, implementing a joint monitoring team to ensure that effective potable water treatment and supply is being done and the bodies involved in water management like the Cameroon Water Utilities Corporation (CAMWATER) need to initiate a platform for multi-stakeholder dialogue, networking and social learning essentially for building trust on how to manage potable water supply in the municipality better.

Open Access Original Research Article

Carbon Sequestration Potential of Urban Green Spaces (PMC Gardens) in Pune City, India

R. Shinde Vijayalaxmi, M. Mahajan Dnyanesh

Journal of Geography, Environment and Earth Science International, Page 22-38
DOI: 10.9734/jgeesi/2021/v25i630291

Aim: To estimate the Carbon sequestration potential of trees in Urban green spaces of Pune city.

Study Design: The methods suggested by Ravindranath and Ostwald were used for measuring the above and belowground biomass and estimation of carbon pool. Random sampling technique was used to collect soil samples. As the study area were one acre and above, each and every tree was sampled for various parameters. The GPS instrument was used for measuring latitude and longitude of each and every tree.

Place and Duration of Study: The gardens developed by Pune Municipal Corporation (total   66 having an area one acre and above) Pune, Three years( from January 2015 to December 2015, January 2016 to December 2016, January 2017 to December 2017)

Methodology: The gardens having an area one acre and above were selected for the work. Each and every tree is sampled along with its position on ground by using GPS instrument. Sampling of tree includes measuring Height and Girth at breast height (GBH). Later, the parameters like Volume, Mass, Wood density, Above and Below ground biomass, Total biomass and Total carbon were calculated as per the standard methods given by Ravindranath and Ostwald [1] Soil samples were collected randomly from a depth of 30 cm as it is a zone of highest microbial activity. Walkley‐Black Wet Oxidation method was used to find out soil organic carbon.

Results: Total amount of above and belowground carbon sequestered was estimated to be 7,00,507.83 tonnes; litter and deadwood 24,904.05, and soil organic carbon 1879.905; and the sum of all were 7,27,291.785 tonnes. The exotic species sequester 2,69,287.4 tonnes and native sequester 80,966.55 tonnes of carbon. The rates of carbon in active markets are US$ 30 (Thirty dollars) per tonne. 

Conclusion: Putting a conservative value of US$ 30 per tonne of CO2 locked in these sampled gardens, this carbon sink of about 7,27,291.785 tonnes of CO2 is worth of US $ 21818753.55 or Indian Rs. 1606733011.422/-It will help in Climate mitigation and reducing the carbon footprints of Pune city.

Open Access Original Research Article

Comparative Assessment of Standard Precipitation Index and Standard Precipitation Evapotranspiration Index as Drought Evaluation Tools in Coastal Winneba-Ghana

Johnson Ankrah

Journal of Geography, Environment and Earth Science International, Page 39-54
DOI: 10.9734/jgeesi/2021/v25i630292

In coastal Winneba-Ghana, drought occurrence negatively affects the ecosystems and agriculture and threatens food security and socio-economic livelihoods. Nevertheless, there exist dearth of information on a detailed statistical evaluation of drought indices over this area. This study made a comparative assessment of Standard Precipitation Index (SPI) and Standard Precipitation Evapotranspiration Index (SPEI) over coastal-Winneba. A daily temperature and rainfall data from 1980-2019 acquired from the Ghana Meteorological Agency was used to perform SPI and SPEI. Pearson correlation coefficient and cross-correlation, and Bland and Altman plot were used to test for the strength and direction and the degree of agreement, respectively between SPI and SPEI. Results showed a strong and positive association between SPI and SPEI (0.90, 0.91, 0.84, and 0.93) at 1-, 3-, 6-, and 12-month timescales, respectively. Results again, showed a good degree of agreement between SPI and SPEI (-0.06138, -0.00736, -0.05211, and -0.01810) at 1-, 3-, 6-, and 12-month timescales, respectively. Results further, showed that while both SPI and SPEI correlated strongly with each other, SPEI performed better in the detection of severe and extreme droughts at all timescales than SPI. Additionally, results showed that in the absence of temperature data to perform SPEI, the SPI can be used since the study found an acceptable degree of agreement scores between SPI and SPEI at all timescales in the study area. The study, therefore, recommends the utilization of numerous drought indices in drought performance assessment at a particular region or locality to arrive at a strong decision.

Open Access Original Research Article

Assessment of Spatial Variation of Physicochemical Parameters of Groundwater in Some Communities of Yenagoa Metropolis

Alfred Wilson Opukumo, Austin O. Oki

Journal of Geography, Environment and Earth Science International, Page 55-71
DOI: 10.9734/jgeesi/2021/v25i630293

Water is a basic need of life, and more so, potable water is critical for healthy living. Shallow boreholes are now popular as the main source of drinking water in the Yenagoa metropolis due to the contamination of surface water and rainwater caused by poor management of wastes and crude oil facilities in the area. However, there are concerns about variations in the quality of groundwater across communities in the Yenagoa metropolis. Thus, this study assesses the spatial variations of physicochemical parameters of groundwater samples from 50 boreholes in the area, and results compared with recommended standards prescribed by the World Health Organization (WHO). Parameters analyzed were pH, electrical conductivity (EC), salinity, total dissolved solids (TDS), nitrate, chloride, sulfate, total alkalinity (TA), total hardness (TH), calcium, magnesium, sodium, potassium, and iron. Global Information System (GIS) technology was adopted to present the groundwater quality in respect to each physicochemical parameter, in thematic maps. The maps showed that groundwater was slightly acidic in most communities in Central and Northern Yenagoa like Ekeki, Swali, Akaba, and Okolobiri. In communities like Ogbogoro, Ekeki, Azikoro and Yenegwe the EC was higher than the standard permissible value according to the WHO. A very high concentration of iron was observed across all communities except a few like Nedogo, Okolobiri, Tombia, Gbarantoru, Ayama, Famgbe, and Ikibiri having iron-free groundwater. Concentrations of TDS, calcium, magnesium, nitrates, sulfates, potassium, and sodium were within permissible limits across all communities. Communities like Ayama-Ijaw, Obololi, Ikibiri, Ikudu, Bomodi, Tombia, and Akaibiri had good groundwater while Ekeki, Famgbe, Yenaka, and Kpansia boast of excellent groundwater quality, and other areas had either poor or unsuitable groundwater for consumption. Treatment is recommended for parameters with higher concentrations than the standard value stipulated by the WHO.