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Kenya, classified as a water-scarce country faces challenges from both natural and
anthropogenic factors compromising the quality and water sources. Surface water sources have
become severely polluted creating a big demand on the use of groundwater as sources of water
for domestic uses mainly through drilling of boreholes. This study focused on quality of borehole
water in Nairobi, Kajiado, Kiambu and Machakos which together form the Nairobi Metropolitan
region. A total of 277 water quality reports were used in this study. 47 % from Nairobi, 19%
Kajiado, 17% Kiambu and 17% Machakos. The study focused at assessing the quality of water
as per the following parameters necessary for water for domestic sources; pH, Color , Turbidity,
Conductivity, Nitrates (NO3), Nitrites (NO2), Calcium Magnesium, Total Hardness, Chlorides,
Fluoride, Ammonia, and Sulphate. The main objective of this study was to assess the status of
borehole sources of water in the Nairobi metropolitan region. The study used data obtained from
water quality reports which were analyzed using MS Excel and the conclusions and
recommendations were made based on the results. From the study, water quality in all Kiambu
boreholes met thee recommended limits for drinking water for Total Dissolved Solids,
Conductivity, Chlorides, Sulphates and Total Hardness levels; Calcium was the only parameter
that all the boreholes in Machakos had values within the recommended limits for drinking water.
Fluoride was the only parameter that recorded levels higher than those recommended for
drinking water in all regions except in Kiambu where only 27.9% of boreholes had values higher
than 1.5mg/l. The study therefore concludes and recommends that borehole water from the
Nairobi Metropolitan region should be treated before being used as drinking water sources.

Groundwater recharge has become a significant practice for sustainable groundwater development and efficient water resource management. Many countries in Africa including Kenya are currently experiencing water scarcity. Kakia and Esamburmbur subcatchment, Narok County in southwest Kenya suffers water shortage during the dry season and surface water sources dry up.
Identifying groundwater recharge zones and estimating groundwater recharge rates in Kakia and Esamburmbur sub-catchment will
help water-resource authorities and policymakers to properly plan and develop groundwater resources in the sub-catchment. A
geophysical survey was executed using the PQWTs-500 equipment to map the sub-surface condition of the study area in order to
determine the suitable recharge zones. Five profile lines were generated of 20.9 km in total with 104 points at 200 m intervals. Soil
and Water Assessment Tool plus (SWAT+) model was used to estimate groundwater recharge rates in the sub-catchment. The SWAT+ model was calibrated and validated with seventeen years (2003 – 2019) of monthly satellite soil moisture data. Model performance values obtained for calibration and validation were coefficient of determination (R2
) 0.51 and 0.59, Nash-Sutcliffe
efficiency (NSE) 0.17 and 0.20, and percent bias (PBIAS) 33.8% and 28.5% respectively. The geophysical survey results showed that the south-central and southeast zones of the sub-catchment are potentially good groundwater recharge zones and therefore suitable for managed aquifer recharge structures to augment the groundwater resources. Additionally, the SWAT+ simulation showed that the long-term average groundwater recharge rate ranges from 0 to 175 mm per year. It was also observed that the highest groundwater recharge occurs in April, May and, June.

Abstract- Groundwater pollution is becoming a major concern
worldwide. The impact of polluted groundwater resources is threefold: artificial water scarcity, human health problems and an
impediment to economic development. Groundwater vulnerability
assessment helps prevent and protect groundwater resources. Mid
River Njoro catchment has experienced increased human settlements,
industrial and intensive agricultural activities over the years,
threatening the quality of water from wells and boreholes. This study
assessed the vulnerability of groundwater resources of the Mid River
Njoro catchment, Kenya, to contaminations, using a modified
DRASTIC model in a GIS environment. The groundwater
vulnerability map prepared using parameters such as groundwater
depth, net recharge, aquifer media, topography, impact of vadose
zones, hydraulic conductivity and land use types. The nitrate
measurements used to validate the vulnerability map. From the results,
three different vulnerability zones determined include very low
(6.1%), low (87.4%) and moderate (6.5%). The validation results
obtained from Pearson’s correlation (0.49) and chi-square (5.01),
revealed a positive relationship between the vulnerability index and
nitrate concentrations. To protect groundwater system from future
deterioration, a protective measure must be put in place before
implementing any human activities that have the potential to cause
groundwater contaminations.

The industrialization process taking place in Africa has led to an overall increase in groundwater abstraction in most countries in the continent. However, the lack of hydrogeological data, as in many developing countries, makes it difficult to properly manage groundwater systems. This study presents a real case study in which a combination of different hydrogeological tools together with different sources of information allow the assessment of how increased competition for water may be affecting groundwater systems by analysing the sustainability of new abstraction regimes under different real climatic condition (before, during and after La Niña 2016). The area where this approach has been applied is Kwale County (in Coastal Kenya) in a hydrogeological context representative of an important part of the east coast of the continent, where new mining and agriculture activities
co-exist with tourism and local communities. The results show that the lack of aquifer systems data can be overcome, at least partly, by integrating different sources of information. Most of the time, water-reliant users collect specific hydrogeological information that can contribute to defining the overall hydrogeological system, since their own main purpose is to exploit the aquifer with the maximum productivity. Therefore, local community water usage, together with different stakeholder's knowledge and good corporate water management act as a catalyst for providing critical data, and allows the generation of credible models for future groundwater management and resource allocation. Furthermore, complementary but simple information sources such as in situ interviews, Google Earth, Trip Advisor and easy-to use analytical methods that can be applied in the African context as in many developing countries, and enables groundwater abstraction to be estimated and the sustainability of the aquifer system to be defined, allowing potential future risks to be assessed.

Abstract
Safe water of adequate quantity, and dignified sanitation, is vital for the sustenance of a healthy and productive human population. In the recognition of this, the United Nations formulated the Sustainable Development Goal No. 6 to ensure access to safe water and sanitation by all by 2030. Actualization of this Goal requires information on the existing status of water resources and
sanitation levels. Knowledge on contamination of groundwater is essential to prevent risks to human health. The objective of this study was to determine groundwater contamination in Kisumu, Kenya. A total of 275 water samples were collected from 22 sites within the informal settlements between December 2016 and December 2017. The samples were analysed for bacterial contamination and physical chemical quality. Thermal tolerant coliform bacteria enumeration was used as a proxy to bacteria contamination, and the pH, turbidity, dissolved oxygen, conductivity, salinity and temperature were used as physical chemical indicators of contamination. The results indicate that groundwater in Kisumu hosed coliform bacteria and therefore didn’t comply with contamination limits for domestic water proposed by WHO and local KEBS standards. The results further indicated that the levels of bacteriological contamination vary with water type, shallow well having the highest bacterial
loads. The study concluded that there were potential risks to human health due to high content of coliform bacteria. The study attributed the contribution to pit latrines that were present in virtually all compounds. The pit latrines are located close to the water points. The study recommended the definition of minimum distance between the pit latrines and shallow wells to minimize contamination. The low income dwellers should be educated on simple ways of treating drinking water contaminated by microbial to minimize enteric infections

Population increase in Thiririka sub-catchment is causing high demand of water against limited supply. Currently, only 12,000 households out of 250,000 in the catchment have access to pipe water.
Groundwater offers the one of the available options to the limited and irregular supply of pipe water. This study aims to find out the extent to which groundwater as alternative source of water for both domestic and irrigation activities is explored in the Thiririka sub-catchment. To achieve this objective, a field survey was conducted using semi-structured questionnaire to seek the extent to which individuals and households use groundwater. The study indicated a very low and adopted use of groundwater in the catchment. Only 36.7% of the various households visited use groundwater for domestic activities and 13.30% for irrigation purposes. It was found out that residents perception on groundwater to be polluted and therefore not safe for domestic activities, lack of cash availability for individuals who wish to construct wells at their homes and lack of awareness and education on the benefits of groundwater are some of the challenges contributing to the low use of groundwater in the Thiririka sub-catchment. It was therefore, recommended that education on the benefits of groundwater by the Gatundu South Water Services and Sanitation office and other NGOs be intensified to the residents of Thiririka sub-catchment and more community boreholes and wells should be provided to the communities by the government, churches and NGOs, beside the pipe connections.

ABSTRACT:- Groundwater is increasingly becoming an important resource within and around the
Ngong area, of Kenya. This is mainly as a result of increase in human population due to rural-urban
migration, industrial expansion and farming activities. Ngong area forms a water catchment zone to
the west of the city of Nairobi in Kenya. The geology of the area is comprised of volcanic layers of
basalts, trachytes, phonolites and tuffs all overlain by thick layers of clay soil. The soil retains water for an extended period of time after the rains and this partly recharges aquifers in the area. Basalts and trachytes form good aquifers whereas tuffs are aquifers only when fractured. Faults delineated from a study of aerial photographs trend in a North-South direction in conformity with the structural pattern of the eastern branch of the Great Rift Valley. The influence of the faults on groundwater is two fold. They act as drainage channels to the flow of groundwater and also as aquifers in the area.