Abstract:The geochemistry of a coastal aquifer was assessed using statistical and geospatial analysis tools for the pre-monsoon, rainy and post-monsoon seasons. Data were obtained from both the field and laboratory analysis of water samples. Statistical methods such as correlation coefficients, piper plots, factor analysis and mixing index were used to gain insights into the geochemistry, while geospatial tools were used to create contours to understand the spatial distribution of the measured groundwater parameters of… Show more
“…The drilling of the boreholes has led to irreversible problems of saline incursion into boreholes and aquifers. A recent hydrogeochemical assessment by Idowu, Nyadawa, and K'Orowe (2017) found that 94% of the water samples tested from the city's north coast exceeded the WHO drinking water limit for all mineral contents, with the principle process influencing the geochemistry being sea water intrusion. Fig.…”
Section: Carry Over Of Inertia From Colonial To Post-colonial Periodmentioning
Amidst climate change, coastal cities in Africa will face serious water and sanitation problems owing to the predicted flooding of coastal land and saltwater intrusion into freshwater aquifers. For cities such as Mombasa, the problems will be further compounded by high prevalence of informal economies and settlements superimposed on western style governance systems. Yet, right from colonisation to the present day, the water supply and sewage systems have been characterised by a series of inequalities in access. This review paper, discusses the water and sanitation backlogs in the coastal city of Mombasa, tracing them from the colonial times to the post-colonial period. Against this background, we overview the current situation of the water and sanitation sector in the city and discuss possible sustainable interventions. We argue that any analysis of the water and sanitation challenges must consider the motive of the development of the infrastructure during the colonial times. We conclude that sustainable water and sanitation services are likely to remain a mirage unless the issues of funding, cost recovery, data availability and overall governance are fully addressed. A good understanding of both historical inadequacies and current investments would help in designing sustainable interventions going forward.
“…The drilling of the boreholes has led to irreversible problems of saline incursion into boreholes and aquifers. A recent hydrogeochemical assessment by Idowu, Nyadawa, and K'Orowe (2017) found that 94% of the water samples tested from the city's north coast exceeded the WHO drinking water limit for all mineral contents, with the principle process influencing the geochemistry being sea water intrusion. Fig.…”
Section: Carry Over Of Inertia From Colonial To Post-colonial Periodmentioning
Amidst climate change, coastal cities in Africa will face serious water and sanitation problems owing to the predicted flooding of coastal land and saltwater intrusion into freshwater aquifers. For cities such as Mombasa, the problems will be further compounded by high prevalence of informal economies and settlements superimposed on western style governance systems. Yet, right from colonisation to the present day, the water supply and sewage systems have been characterised by a series of inequalities in access. This review paper, discusses the water and sanitation backlogs in the coastal city of Mombasa, tracing them from the colonial times to the post-colonial period. Against this background, we overview the current situation of the water and sanitation sector in the city and discuss possible sustainable interventions. We argue that any analysis of the water and sanitation challenges must consider the motive of the development of the infrastructure during the colonial times. We conclude that sustainable water and sanitation services are likely to remain a mirage unless the issues of funding, cost recovery, data availability and overall governance are fully addressed. A good understanding of both historical inadequacies and current investments would help in designing sustainable interventions going forward.
“…Three of the megacities (with population > 10 million) to emerge in Africa by 2030, -Lagos, Luanda, and Dar es salam -, are coastal (UNDESA 2018). The population increase experienced by these coastal cities, coupled with climate change-related events aggravate coastal challenges like seawater intrusion and groundwater contamination (Ezekiel et al 2016, Idowu et al 2017, coastal flash floods (Ajibade et al 2013), urban sprawls (Li et al 2016), land subsidence (Showstack 2014) amongst others. These challenges necessitate deliberate and proactive management plans for sustainable development.…”
The most extensive urban growths in the next 30 years are expected to occur in developing countries. Lagos, Nigeria - Africa’s second most populous megacity- is a prime example. To achieve more sustainable and resilient cities, there is a need for modeling the urban growth patterns of major cities and analyzing their implications. In this study, the urban growth of Lagos state was modeled using the Multi-Layer Perceptron (MLP) neural network for the transition modeling and the Markov Chain analysis for the change prediction, achieving a model accuracy of 81.8%. An innovative visual validation of the model results using the ArcGIS was combined with kappa correlation statistics. The results show that by 2031, built-up areas will be the most spatially extensive LULC class in the study area with percentage coverage of 34.1% as opposed to 9% in 1986. The coverage of bare areas is also expected to increase by 53% between 2016 and 2031. Conversely, 24.9% and 68.3% loss of forestlands and wetlands respectively, are expected between 2016 and 2031. In view of the 11th goal of SDGs which focuses on achieving sustainable cities and communities, the objectives of African Union’s Agenda 2063, and based on the urban growth trends observed, the study recommends a prioritization of vertical expansion as opposed to the current horizontal urban growth trends in the study area.
“…The ocean water intrusion during high tides, dissolving bedrocks and industrial waste deposition are suspected cause for the salinity of the rivers and any other surface water source [3,4]. The quality of water for both domestic and Agricultural use has been evaluated in several studies in several countries including Kenya [4,[28][29][30][31][32][33][34][35][36][37][38][39][40][41][42]. However, none was conducted in Kilifi County.…”
Water has economic and ecological significance. However, quality deterioration due to salinity causes significant decrease in agricultural productivity and a public health problem. This study focuses on hydro-chemical and microbial quality of water sources in Kilifi County. Water samples were collected from 25 different locations within Kilifi County and indicators of salinity and microbial load analyzed. Temperature, pH, EC and TDS were determined using portable pH meter. Anions; F-, Br-, Cl-, SO42-, PO43-, NO2-, NO3-, CO32-, HCO3- and NH4+ were determined using Ion Exchange Chromatography. Cations; Na+, K+, Ca2+, Mg2+, Zn2+, Fe2+, Cd2+, Cr3+, Al3+ and Ag+ were determined using flame photometry. Standard methods were used to determine Microbial loads. Results were pH (7.42±0.52), Temperature (24.61±0.21oC), EC (3.44±0.75 dscm-1), TDS (1672.53±122.87 mgL-1) and Turbidity (152.29±41.20 NTU). Anions; F- (2.90±0.24 mg/L), Cl- (1756.68±900.50 mg/L), NO2- (4.47±0.49 mg/L), Br- (11.72±1.20 mg/L), NO3- (4.67±0.38 mg/L), HCO3- (200.54±25.58 mg/L) PO43- (0.94±0.10 mg/L), CO32- (29.94±2.32 mg/L), and SO42- (300.64±42.47 mg/L). Cations; K+ (8751.80±214.04 mgL-1), Na+ (59.43±1.98 mgL-1), Ca2+ (4.00±0.16 mgL-1), Mg2+ (59.43±1.98 mgL-1), Zn2+ (0.76±0.30 mgL-1), Cu2+ (0.18±0.01 mgL-1), Ag+ (0.03±0.01 mg/L), Cd2+ (0.07±0.01 mg/L), Cr3+ (0.35±0.01 mg/L), Al3+ (0.33±0.01 mg/L) and NH4+ (2.01±1.96 mg/L). Microbial load; MPN (20811.00±402.00), Total coliforms (2970.00±60.00 CFU 100 mL-1), E. coli (26.00±3.00 CFU 100mL-1), S. aureus (411.00±12.00 CFU 100mL-1), Shegela (24.00±2.00 CFU 100mL-1) and S. typhi (67.00±2.00 CFU 100mL-1). Temperature, pH, EC, TDS, Turbidity, F-, Cl-, Br-, PO43-, Na+, Zn2+, Fe2+ and microbial load were above WHO limits whereas SO42-, NO2-, NO3-, CO32-, HCO3-, NH4+, K+, Ca2+, Mg2+, Cd2+, Cr3+, Al3+ and Ag+ were below WHO limits. The study concludes that water sources in Kilifi County are unsuitable for domestic and agricultural uses. It’s recommended that a continuous water quality monitoring program be put in place and development of effective management practices for utilization of the surface water resources be instituted.
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