Water Quality Index (WQI) computation method based on quality parameters' selection, assigning of weights, creation of sub-indices and calculation of the aggregated quality value has been used for many decades from the early 1960s to check on the pollution stati of watersheds. Today, due to rising water demand in the face of increased drought induced water shortage challenges and rampant pollution of the water sources, consumers augment their needs by using groundwater resources like in the case of Langata sub County in Nairobi city-Kenya. Little however, has been done to assess the overall potability of groundwater quality here. Accordingly, in the present study, a Water Quality Index (WQI) was developed by Weight Arithmetic Water Quality Index (WAWQI) method to fill that identified gap using a five categories' grading scale, viz. excellent (A), very good (B), good (C), fairly good (D), suitable (E) and unsuitable (F). To realize this, chemical parameters' concentration ranges were defined on the basis of the Kenyan Standards (KS) and International Standards of World Health Organization (WHO).Subsequently, a total of eight chemical parameters were selected based on their level of occurrence in borehole commissioning data obtained from Water Resource Management Authority's database of the area viz; K+, Na+, Ca2+, Fe2+, F-, Cl-, SO4-2 and Ec (µS/cm). Out of a total of 137 boreholes, only 39 had complete eight chemical parameters. These 39 boreholes' water quality assessment is taken in this study as a true representation of the entire area's groundwater quality. The individual concentrations were spatially plotted using Surfer Software's digital terrain model (DTM) which produced contoured maps in different chroma saturations including the overall aggregated concentration to facilitate scale ranking. The WQI for the study area is 53.18 in a scale of 1 to 100, with one being excellent. In this case, the groundwater quality was ranked as grade 'C'. WQI calculation method is known to improve the understanding of water quality issues by integrating a suite of data into a single value which describes the status of water quality. WQI is very useful for the water management authorities because it facilitates their informing of the public on water quality in a simplified form.

Studies on urban water supply service improvements continue to draw interest across the world. The pressure on freshwater resources is increasing in every region in the face of an increasing demand and climate change dynamics. Langata sub County in Nairobi city, Kenya faces drought induced water shortage and households rely on water vending and bottled water purchases to augment the inadequate municipal water supplies. Little to our knowledge has been done to assess the cost implication of such a practice here. So the study used household survey method to collect monthly households' water bills comprising; utility company, water tanker delivery and bottled water purchase from a randomly sampled 382 households spread within the five wards; Karen, South C, Mugumoini, Nairobi West and Nyayo Highrise. The gated communities identified are 57. Simple stochastic analysis of the data was done after data cleaning using MS Excel. It was found that the municipal water serves up to 91.15% of the total average household monthly water demand with a cost share of 27.91%. Water tanker delivery meets 8.61% of the household water demand with a cost share of 50.74%. The bottled water purchases serve 0.24% of a typical household water demand with a total cost share of 21.35%. The water supply deficit which is a mere 8.85% met by tanker deliveries and bottled water purchases has a total average cost share of 72.09%. The computed cost burden is 258%. This means that the households pay more than two and a half times extra above the utility bill per month. The study recommends a new water policy that will incorporate the role of water vendors operated on a cooperative model by the gated communities using standard guidelines. How to cite this paper: Ochungo, E.A., Journal of Water Resource and Protection vulnerability of public water supply systems to impacts of climate variability [26] [27] [28].Accordingly, households nowadays do supplement with vended water transported by one or a number of these methods: head-ported or hand-held water containers [29], walking tractors, bicycles, hand-carts/donkey carts [30] [31], motorbikes and owner-managed water access systems for a home or a community [32]. One other popular coping strategy is buying from neighbors; a practice found in Accra city, Ghana according to [33]. Such daily distressful struggles for water access service makes urban dualism concept real as the beneficiaries are known to be living in urban settings with on-site water utility infrastructure [34] [35]. Further, the selection of a choice of water source with a suitable quality is not easy [36]. Despite the prevailing choice quandary, water vendors serve about 10% -69% of households in developing nations' cities [37]. On the other hand, selling of water to customers is a very important economic activity to the vendors [38]. That is why they always choose to ignore repugnant waterscape labels like 'mafias' as in Bangalore city, India [39].

Several studies have documented that Africa's infrastructure construction firms often do not meet defined project objectives regarding; time, budget and functionality. This has often caused; delays, abandonment or disillusionments on the side of investors. Several contributing factors to these failures have been identified. However, very little if at all, seems to have been done on the project management readiness of African construction firms. Accordingly, this paper sought to assess Africa's construction industry readiness to deliver the priority action projects. Using literature review method, the study established that Africa has a huge technical skills gap which is the main reason for the dismal performance in construction projects' delivery. A readiness training model was developed for policy planners and educational practitioners to help build Africa's human capacity in infrastructure project management. The paper strongly recommends for the adoption of the model. And with that, the Africa's construction stakeholders may gradually improve their project management readiness.

Interest on the investigation of groundwater depletion threat is growing globally and Langata sub County in Nairobi, the capital city of the Republic of Kenya, is not an exception. Because of drought-induced water shortage, households in Langata do rely on borehole water to augment their intermittent municipal water supply system. Consequently, there is an upsurge of borehole developments as drought events unfold. Previous studies here have focused on impact of borehole depths and density yet little seems to have been done to compute the correlation coefficient between drought events data and historical borehole development records as an assessment for groundwater "grab" syndrome. This study used drought index computation method (SPI) alongside other statistical methods to seek the answer to the problem. Using 57 years of monthly rainfall data and 26 years of borehole development data, the study established that, there is a positive correlation coefficient. Similarly, a trend analysis of borehole drilling and struck water level depths indicated a positive parallel rising trend on both. Further, when the borehole distribution map and struck water level contour maps were plotted, a sign of a probable well interference during pumping was detected, which however, requires a new investigation to confirm the syndrome of groundwater depletion threat. The study has contributed to the groundwater depletion research by deploying statistical research methods for risk detection. Finally, the study has proposed for a new groundwater management policy that will encourage initiation of artificial recharge schemes for the study site and beyond.