ISSN: 2148-9173 Vol: 6 Issue:1 April 2019 International Journal of Environment and Geoinformatics (IJEGEO) is an international, multidisciplinary, peer reviewed, open access journal. Groundwater Quality Analyses along Kenyan Coastal Region, Case Study of Kilifi-KENYA Mary MAKOKHA Chief in Editor Prof. Dr. Cem Gazioğlu Co-Editor Prof. Dr. Dursun Zafer Şeker, Prof. Dr. Şinasi Kaya, Prof. Dr. Ayşegül Tanık and Assist. Prof. Dr. Volkan Demir Editorial Committee (2019) Assos. Prof. Dr. Abdullah Aksu (TR), Prof. Dr. Bedri Alpar (TR), Prof. Dr. Lale Balas (TR), Prof. Dr. Levent Bat (TR), Prof. Dr. Paul Bates (UK), Prof. Dr. Bülent Bayram (TR), Prof. Dr. Luis M. Botana (ES), Prof. Dr. Nuray Çağlar (TR), Prof. Dr. Sukanta Dash (IN), Dr. Soofia T. Elias (UK), Prof. Dr. A. Evren Erginal (TR), Assoc. Prof. Dr. Cüneyt Erenoğlu (TR), Dr. Dieter Fritsch (DE), Assos. Prof. Dr. Çiğdem Göksel (TR), Prof.Dr. Lena Halounova (CZ), Dr. Hakan Kaya (TR), Assoc. Prof. Dr. Maged Marghany (MY), Prof. Dr. Michael Meadows (ZA), Prof. Dr. Nebiye Musaoğlu (TR), Prof. Dr. Erhan Mutlu (TR), Prof. Dr. Masafumi Nakagawa (JP), Prof. Dr. Hasan Özdemir (TR), Prof.Dr. Chryssy Potsiou (GR), Prof. Dr. Erol Sarı (TR), Prof. Dr. Maria Paradiso (IT), Prof. Dr. Petros Patias (GR), Prof. Dr. Elif Sertel (TR), Prof. Dr. Nüket Sivri (TR), Assoc. Prof. Dr. Füsun Balık Şanlı (TR), Prof. Dr. Uğur Şanlı (TR), Assoc. Prof. Dr. Oral Yağcı (US), Prof. Dr. Seyfettin Taş (TR), Assoc. Prof. Dr. Ömer Suat Taşkın (TR), Dr. İnese Varna (LV), Dr. Petra Visser (NL), Prof. Dr. Selma Ünlü (TR), Assoc. Prof. Dr. İ. Noyan Yılmaz (AU), Prof. Dr. Murat Yakar (TR), Assit. Prof. Dr. Sibel Zeki (TR) Abstracting and Indexing: DOAJ, Index Copernicus, OAJI, Scientific Indexing Services, JF, Google Scholar International Journal of Environment and Geoinformatics 6(1): 01-14 (2019) Reaserch Article Groundwater Quality Analyses along Kenyan Coastal Region, Case Study of Kilifi-KENYA Mary Makokha Geography Department, Kenyatta University, P.O Box 43844, 00100 GPO, Nairobi KENYA Corresponding author: Makokha Mary Received 03 Oct 2018 E-mail:[email protected] .ke Accepted 12 Feb 2019 How to cite: Makokha, M. (2019). Groundwater Quality Analyses along Kenyan Coastal Region, Case Study of Kilifi-KENYA, International Journal of Environment and Geoinformatics (IJEGEO), 6(1): 01- 14. DOI: 10.30897/ijegeo.466933 Abstract The Kenyan coast is a semi-arid region frequently faced with severe water scarcity especially during prolonged drought and a rapid population growth. Groundwater provides 50% of the water demand and most sources are poorly drilled, over-abstracted and abandoned. The aquifers occur in sedimentary formations of fluvial and lacustrine origin. There is a need to have a groundwater monitoring system in place; therefore this study analyses selected physico- chemical and microbial parameters using both laboratory and field methods. Arc-GIS 9.3, SURFER were used to generate thematic maps for some tested parameters. Results indicate pH values within acceptable range of 6.5 – 8.5, though shallow wells in Malindi were acidic, this atrributed to the heavy industries prevalent in the area. Electric conductivity (EC) was above the set standard of 1500µS/m indicating high dissolved ions present especially in Magarini where salt mining is done. Total dissolved solids (TDS) of up to 500mg/L suitable for drinking water was only found during the wet season. Turbidity of less than 5 NTU was established in most areas. Chlorides and salinity levels exceeded 250mg/L pointing to the saltwater intrusion problem that is a challenge along Kenyan coastal aquifers Boreholes and shallow wells had a total hardness ranging from 50mg/L -150mg/L indicating the water was ranging from being slightly hard to hard water. Escheriria coli was present in almost all the boreholes and shallow wells indicating the need to treat water before use. Water Quality index (WQI) calculation indicate that groundwater is unsuitable for human consumption in dry season. Keywords: Groundwater, boreholes, water quality, shallow wells Introduction water sources, rainwater harvesting and enhancing the utilization of groundwater (GoK, 2008). Groundwater Access to safe and sufficient water and sanitation is a provides the only realistic water supply option for basic human need and is essential to human wellbeing meeting dispersed rural demand, as alternative water (UN, 2006, Barut, 2015; Kisaka, 2018) but presently, resources can be unreliable and expensive to close to a billion people mostly living in the developing develop (Foster et al., 2000; McDonald et al., 2005; world do not have access to safe and adequate water Ülker et al., 2018). (UNICEF/WHO, 2012). One of the United Nations Although groundwater has historically been thought to Millennium Development Goals (MDG) specifically be free of microbial contamination, recent studies have addresses the problem of lack of access to safe drinking indicated that groundwater can be contaminated and this water. Worldwide, water borne diseases are a major could easily result in water borne diseases if consumed cause of morbidity and mortality in humans (WHO, without prior treatment (Momba & Mnqumevu, 2000; 1996; Gazioğlu et al., 2010; Esetlili et al., 2018). While Momba et al., 2006). An investigation was conducted in water borne pathogens infect around 250 million people the Kilifi which lies within the Kenyan coastal region to per year, resulting in 10–20 million deaths (Anon, 1996), determine the safety of groundwater sources and to many of these infections occur in developing nations that examine the factors influencing groundwater quality. have sanitation problems (Nsubuga et al., 2004; The county falls within the semi-arid region which Khorrami et al., 2018). Approximately 6000 children, frequently faces severe water scarcity especially during most of them in developing countries, die every day of periods of prolonged drought. Kilifi County receives diseases related to inadequate sanitation and a lack of water supply mainly from Kilifi-Mariakani Water and access to safe drinking water (Louise, 2005). The Sewerage Company (KIMAWASCO), mandated by the majority of the population in developing countries are Coast Water Service Board and it provides water to 40% not adequately supplied with potable water and are thus of the growing population. Like most of the aquifers compelled to use groundwater from sources like shallow found in the coastal areas, the deep aquifers in Kilifi wells and boreholes that are unsafe for domestic and County have been encroached with salty water from the drinking purposes due to high possibilities of ocean which has greatly interfered with the quality of contamination (WHO 2006, 2011). Kenya’s Vision 2030 water. This has seen many boreholes that have been has attempted to address this lack of equity in the supply drilled in the area abandoned over time. The of potable water by advocating for the conservation of groundwater in the county occurs in confined and 1 Makokha / IJEGEO (6)1: 01-14 (2019) unconfined aquifers in sedimentary formations of fluvial Location of the Study Area. and lacustrine origin. Scarcity and unpredictability of Kilifi Town is located in the coastal area of Kenya and it rainfall in Kilifi County is a major impediment to covers an area of 4779.2 square km. Its geographic development. Some parts of Kilifi County such as Ganze coordinates are 3 ̊ 38’ 00S to 3 ̊ 40’ 00S latitudes and 39̊ and Bamba on the western part experience 5-6 months of 45’ 00E to 39̊ 51’ 00E longitudes. It is located at an continuous dry weather. Groundwater provides nearly elevation of 150 metres above the sea level. The District 50% of the water in Kilifi County and it is mainly used consists of seven divisions: Bahari, Kikambala, Chonyi, for domestic and agricultural water supply. Due to the Kaloleni, Bamba, Ganze and Vitengeni. Figure 1 rapid population growth groundwater sources are poorly illustrates the map of the study area. The district has a drilled, there is an overexploitation and salt water strong industrial sector with the Mabati Rolling Mill, the intrusion problem. Athi River cement Factory, Cashew Nut Milling Industry and Salt Processing Factory that contribute to the There is a need to have a groundwater quality region’s economy both in employment provision and monitoring system in place and therefore this research income generation. examines the groundwater quality and to determines its suitability for domestic purposes. Groundwater samples Climatic Conditions from 9 Boreholes and 10 Shallow wells were sampled and analysed for selected physic- chemical and microbial Rainfall is bimodal; short rains occurring in October to parameters. Standard methods were used for the analysis December while long rains in March to June. Rainfall of groundwater samples in the laboratory. Results were intensity varies from 400mm in the hinterland to compared to guideline values of the NEMA, USEPA and 1300mm in the high potential areas in the coastal plains. WHO to establish its suitability for domestic use. The Most of the divisions are located in the hinterland and Water quality Index (WQI) was calculated to determine experience less rainfall hence Kilifi County falls under the portability of the groundwater in Kilifi. Arc-GIS 9.3, the coastal dry areas. It has high temperature ranging SURFER were used to generate a thematic map for some from 21̊ to 35̊ C. of the tested parameters. Figure 1. Map of Kilifi Area 2 Makokha / IJEGEO (6)1: 01-14 (2019) Drainage Patterns and Sources of Water in Kilifi. Duruma series (Maji ya Chumvi beds and Mariakani The drainage pattern in Kilifi County is formed by sandstone – have the highest shale content). Mariakani seasonal rivers and streams such as Goshi, Mzovuni, sandstone consists of Silty shales and fine grained Wimbi and Mtamkuu. The Sabaki River the only sandstones. Tertiary sediments consist of the Magarini perennial river, originating in the central highlands. sands which has a thickness of about 130m.