Water Resources Management Authority Research Articles

The Influence of Procurement Practices in Commercialization of Water, and Private Service Delivery in Nairobi County, Kenya

Aim: The purpose of the study was to discuss the effect of procurement practices on commercialization of water and private service delivery in Nairobi City County, Kenya. Methods: Quantitative and Qualitative methodologies of data collection and analysis were implored in this research. The Collection of the data was through key informant interviews and questionnaires. Secondary data was obtained from library research materials, internet search and document analysis. The researcher used descriptive and content analysis techniques to analyze the data. Simple random sampling was used in selecting participants from Nairobi City residents. The target population was 4,397,073 Nairobi City County Residents and 635 Staff of the Ministry of Water, Sanitation and Irrigation; two departments were targeted in the Ministry i.e. The Water, Sewerage and Sanitation Development department and The Water Infrastructure Development Department which has a total of 168 in-post staff. Results: The study found that the components of commercialization of water greatly influences the quality control and equal access to water by the residents. These components are procurement practices, standardization machinery, and the supervision mandate by governmental agencies i.e. WASREB (Water Services Regulatory Board) and WARMA (Water Resources Management Authority). The study concludes that having good procurement practices in place, fosters integrity and professionalism in private water service provision. Recommendations: There is need for the government through its approved agencies WASREB and WARMA, to tailor-make policies that would better suit the unique Kenyan societies’ informal service providers, instead of unifying them all to be governed by a single policy. There is need to ensure private water service vendors provide quality and affordable services set out by government and its agencies. The government ought to thoroughly investigate the private water enterprises that have applied to be licensed to provide water services; not just at the national level but also the small-scale water kiosks-ought to be thoroughly scrutinized. The governmental agency WASREB ought to conduct more impromptu checks on WSPs (Water Service Providers) as opposed to only limiting itself to doing quarterly checks and visits.

Effects of Governance Systems on Organizational Performance of Water Service Companies in Kenya

Good Governance is a process whereby public and private institutions manage resources to promote development, human rights, justice, peace, accountability, responsiveness, inclusiveness, democracy, and adherence to the rule of law. However, there are many challenges in the governance systems, including politics, corruption, lack of transparency, and lack of accountability. This research focused on the governance systems of water sector companies in Kenya from 2002 to 2021. The purpose of this study was to determine the effects of governance systems on the organizational performance of water service companies in Kenya. The study was limited to 79 registered Water and Sanitation companies in Kenya and 47 Senior Executives in charge of water and sanitation in every county in Kenya, and the CEOs/Senior Executives of the two water regulatory bodies, Water Services Regulatory Board (WASREB) and Water Resources Management Authority (WRMA). The following theories were used; The Systems Theory, The Good Governance Theory and The Resource-Based View Theory. To determine the sample size, simple random sampling techniques were used. Self-administered questionnaires and interview guide questions were used to collect primary data. A sample size of 281 respondents was used. The data was analysed using the Statistical Package for the Social Sciences (SPSS). Correlation and linear regression techniques were used to test the research hypotheses. The study found that water governance framework and performance had a statistically significant linear relationship (r= 0.524, p<.05). The study revealed that water framework variables account for 52.4% of the variability in the performance of water service companies in Kenya. The findings from the regression model indicated that the governance framework significantly influences the organisational performance of water service companies (β = 0.311, p<0.05). The results of this study may be used by water service companies and County Governments in the formulation and implementation of strategies regarding water governance.

A partial least squares-path model of environmental degradation in the Paraopeba River, for rainy seasons after the rupture of B1 tailings dam, Brumadinho, Brazil

The present study aimed to investigate the rupture of B1 tailings dam of Córrego do Feijão mine, which drastically affected the region of Brumadinho (Minas Gerais, Brazil). The contamination of water resources reached 155.3 km from the dam site. In the river channel, high concentrations of Mn, Al, As and Fe were detected and correlated to the spillage of the tailings in the river. The presence of the tailings also affected the chlorophyll-a content in the water, as well as the reflectance of riparian forests. With the increase of metal(oid) concentrations above permitted levels, water management authorities suspended the use of Paraopeba River as resource in the impacted areas, namely the drinking water supply to the Metropolitan region of Belo Horizonte. This study aimed to evaluate possible links between tailings distribution, river water quality, and environmental degradation, which worked as latent variables in partial least squares regression models. The latent variables were represented by numerous physical and chemical parameters of water and sediment, measured four times in 22 locations during the rainy season of 2019, in addition to stream flow and to NDVI evaluated in satellite images processed daily. The modeling results suggested a relationship between river flow turbulence and increased arsenic release from sand fractions, as well as desorption of Mn from metal oxides, both representing causes of water quality reduction. They also revealed increasing iron concentrations affecting the forest NDVI (greening), which was interpreted as environmental degradation. The increase of chlorophyll-a concentrations (related with turbidity decreases), as well as the increase of river flows (responsible for dilution effects), seemed to work out as attenuators of degradation. Although applied to a specific site, our modeling approach can be transposed to equivalent dam failures and climate contexts, helping water resource management authorities to decide upon appropriate recovery solutions.

Water Balance Evaluation for Flood Risk Reduction in the Yala River Basin, Western Kenya

The Yala River Basin (YRB) in Western region of Kenya has in the past experienced climate and weather extreme events that include floods. Floods have triggered loss of lives, destruction of property, outbreak of water borne diseases and siltation of arable land. This study utilized the Nedbør-Afstrømnings-Model (NAM) hydrologic model (available in the NAM Module of the MIKE 11 hydrodynamic model) on the Yala River Basin (YRB) to generate flood flows for water balance evaluation. The study utilized satellite imagery data for the period 1984-2010 sourced from the Regional Centre for Mapping of Resources for Development, rainfall (1980-2012) and river discharge (1947-2012) data sets from the Kenya Meteorological Department (KMD) and the Water Resources Management Authority (WARMA), respectively. Data quality control was statistically checked before sensitivity analysis, calibration, validation, and simulation of the flood flows. Daily water balance estimates for the Yala River Basin (YRB) over the period 1980-2010 were developed using the NAM hydrologic model. The results indicate that the mapped flood area extent varied by a value of 34.23 km2 over the period 1980-2010. The Yala River Basin (YRB) indicated an estimated inflow value of 4,814.72 MCM and outflow value of 4,578.23 MCM, with a coefficient of determination of 0.867. The difference between the inflow and outflow values was 236.49 MCM, that formed the flood flow or the water balance. This study concluded that the water balance value of 236.49 MCM was responsible for the floods recorded in the Yala River Basin (YRB) for the period 1980-2010, and it should be taken care of through flood risk reduction initiatives.

Evaluation and projection of the annual maximum streamflow in response to anthropogenic and climatic effects under nonstationary conditions in the Hanjiang River Basin, China

Abstract The flood regimes have been changing due to the climate change and human activities. Evaluating the flood risk under nonstationarity is critical to water resource management authorities in disaster reduction. In this study, the annual maximum streamflow (AMS) was used to analyze the nonstationarity in flood frequency in the Hanjiang River (HJR) Basin. A Generalized Additive Model for Location, Scale and Shape (GAMLSS) is employed to characterize nonstationarity in the AMS with time, as well as climatic and anthropogenic factors. Additionally, changes of the AMS in response to future climate change and human activity are also investigated. Results indicate that flood behavior can be better described by the nonstationary model with physically based covariates than that with time and the stationary model, implying that flood regimes of the HJR Basin are mainly influenced by anthropogenic and climatic factors including reservoir, precipitation and temperature. The precipitation and temperature projected by the Statistical Downscaling Model (SDSM) under two climate scenarios (RCP2.6 and RCP4.5) in the HJR Basin are characterized by an increasing trend over the period of 2006–2100. Furthermore, an increasing trend was found in the AMS during 2051–2100, indicating that flood risk is likely to increase in the future in the HJR Basin due to the climate change alone without further changes in hydrological engineering and flood management. The results quantified the flood frequency under nonstationarity conditions with physically based covariates and provided information to the decision-makers to address the potential risks posed to the HJR Basin.

Water Quality Management Using Hybrid Machine Learning and Data Mining Algorithms: An Indexing Approach

One of the key functions of global water resource management authorities is river water quality (WQ) COD assessment. A water quality index (WQI) is developed for water assessments considering numerous quality-related variables. WQI assessments typically take a long time and are prone to errors during sub-indices generation. This can be tackled through the latest machine learning (ML) techniques that are renowned for superior accuracy. In this study, water samples were taken from the wells in the study area (North Pakistan) to develop WQI prediction models. Four standalone algorithms, i.e., random trees (RT), random forest (RF), M5P, and reduced error pruning tree (REPT), were used in this study. In addition, 12 hybrid data-mining algorithms (combination of standalone, bagging (BA), cross-validation parameter selection (CVPS), and randomizable filtered classification (RFC)) were also used. Using the 10-fold cross-validation technique, the data were separated into two groups (70:30) for algorithm creation. Ten random input permutations were created using Pearson correlation coefficients to identify the best possible combination of datasets for improving the algorithm prediction. The variables with very low correlations performed poorly, whereas hybrid algorithms increased the prediction capability of numerous standalone algorithms. Hybrid RT-Artificial Neural Network (RT-ANN) with RMSE = 2.319, MAE = 2.248, NSE = 0.945 and PBIAS = -0.64, outperformed all other algorithms. Most algorithms overestimated WQI values except for BA-RF, RF, BA-REPT, REPT, RFC-M5P, RFC-REPT, and ANN- Adaptive Network-Based Fuzzy Inference System (ANFIS).

Assessment of Rainfall, Streamflow and Reservoir Level Trends for Malewa River Catchment, Naivasha, Kenya

Appropriate water quality and quantity are critical problem greatly affecting significant proportion of the population particularly those living in semi-arid and arid areas. Rainfall characteristics, streamflow and reservoir levels are some of the key hydro-meteorological variables within a catchment in the determination of sufficiency of water quantity. Lake Naivasha reservoir level continues to be hit by anthropogenic stressors such as loss of wetlands, water abstraction and eutrophication. Also there has been a lot of fluctuation in flow discharge of Malewa River over the years where the tributaries (Turasha and Karati streams) usually dries up during dry season. This paper presents the results of a research to assess the time series trends of rainfall, streamflow and lake basin levels data in the catchment from 1980-2018 using Mann-Kendall trend test to assess water quantity status. Monthly stream flow, rainfall and reservoir level data in the catchment were obtained from Water Resources Management Authority (WRMA) and Kenya Meteorological Department (KMD) for the years 1980-2018. Non-parametric Mann-Kendall rank statistics test was used to examine the trend components of hydro-meteorological variables. The P-values were used to test whether the null hypotheses were statistically significant (α<0.05) at a 5% level of significance. Rainfall values had an increasing trend from 2011 onwards but not statistically significant while annual streamflow values had no trend as P-value showed weak evidences to rejected the null hypothesis. Reservoir level had an upward trend in years 1981, 2001, 2003, 2012 and 2018 while downward trends in 1980, 1982, 1984, 1986, 1987, 2000, 2004, 2008 and 2014. From 2010 onwards, in monthly data, there have been upward water levels in the lake as shown by the trend. These show that the hydro-meteorological indicators in the catchment are independently trending, therefore some other factors such as land cover changes or climate changes were adversely affecting the hydrological cycle. These findings are helpful for planning and management in water resource systems such as forecasting water distribution and mitigate flood and drought.

Spatiotemporal monitoring of hydrilla [Hydrilla verticillata (L. f.) Royle] to aid management actions

AbstractHydrilla is an invasive aquatic plant that has rapidly spread through many inland water bodies across the globe by outcompeting native aquatic plants. The negative impacts of hydrilla invasion have become a concern for water resource management authorities, power companies, and environmental scientists. The early detection of hydrilla infestation is very important to reduce the costs associated with control and removal efforts of this invasive species. Therefore, in this study, we aimed to develop a tool for rapid, frequent, and large-scale monitoring and predicting spatial extent of hydrilla habitat. This was achieved by integrating in situ and Landsat 8 Operational Land Imager satellite data for Lake J. Strom Thurmond, the largest US Army Corps of Engineers lake east of the Mississippi River, located on the border of Georgia and South Carolina border. The predictive model for presence of hydrilla incorporated radiometric and physical measurements, including remote-sensing reflectance, Secchi disk depth (SDD), light-attenuation coefficient (Kd), maximum depth of colonization (Zc), and percentage of light available through the water column (PLW). The model-predicted ideal habitat for hydrilla featured high SDD, Zc, and PLW values, low values of Kd. Monthly analyses based on satellite images showed that hydrilla starts growing in April, reaches peak coverage around October, begins retreating in the following months, and disappears in February. Analysis of physical and meteorological factors (i.e., water temperature, surface runoff, net inflow, precipitation) revealed that these parameters are closely associated with hydrilla extent. Management agencies can use these results not only to plan removal efforts but also to evaluate and adapt their current mitigation efforts.

Non-stationarity analysis of extreme water level in response to climate change and urbanization in the Taihu Basin, China

Regional climate change as well as urbanization are likely to introduce characteristics of non-stationarity in the extreme water levels (EWL), which in turn will affect the possibility of flooding in the plain river network region. For this study, China’s Taihu Basin as a typical case for analyzing the impacts that climate change and urbanization will have on changes in the EWL. Additionally, changes in the response that EWL will have toward future climate change and urbanization are also studied. A generalized additive model for location, scale and shape (GAMLSS) model with time (t), precipitation (pre) and population (pop) as major predictors was constructed to empirically investigate. Results indicate that the time dependent variables of the GAMLSS clearly describe the temporal variation of the EWL. The GAMLSS with physically-based covariates can capture additional details regarding the changing properties of EWL. According to changes exhibited in the EWL Akaike information criterion values, it is found that the impacts of climate change covariates are larger than that of the urbanization covariates. Additionally, for the study’s sample period of 2015–2099, an increasing trend is found for EWL under the RCP2.6 and RCP4.5 scenarios. It is concluded that flooding risk is likely to increase in China’s Taihu Basin with changing environment conditions, and that some necessary measures should be taken by local water resource management authorities to address the potential risks posed to the region.

Effects of Sedimentation on Small Reservoirs in the Mushibemba Catchment, Mkushi Farm Block, Central Zambia

Sedimentation is one of the problems that affects the storage capacity of most small reservoirs, and if not addressed on time it may lead to the dams being filled up with sediment. The aim of this study was to assess the effects of sedimentation on the storage capacity losses of Moffat dam and GRZ Weir located in the Mushibemba Catchment of Mkushi Farm Block, Central Zambia. The method used to understand reservoir storage capacity loss was bathymetry survey using the hydrographic survey boat (RC-S2) which consists of an echo sounder and a Differential GPS. Information on the initial storage capacity of the two reservoirs was obtained from the Water Resources Management Authority (WARMA). The analysis of the data revealed that the measured volumes of Moffat dam and GRZ Weir were 1,180,462 m3 and 197,218 m3, respectively. The estimated storage capacity losses for Moffat reservoir was found to be 223,789 m&amp;sup3; and 53,312 m3 for the GRZ Weir.&amp;nbsp; The estimated rates of sedimentation loss were found to be 13,986.81 m3 yr-1 (Moffat reservoir), with a lifespan of 84 years, and 1,480.89 m3 yr-1 (GRZ Weir) with a lifespan of 133 years. The source of the accumulated sediment was mainly attributed to originate from the cleared commercial agricultural land which predominantly consists of clayey to loamy soils. This also accounted for the high turbidity of the reservoir water. This situation therefore calls for periodic dredging of the deposited sediment to increase reservoir storage capacity.

Assessing the recharge process and importance of montane water to adjacent tectonic valley-plain groundwater using a ternary end-member mixing analysis based on isotopic and chemical tracers

A study in eastern Taiwan evaluated the importance of montane water contribution (MC) to adjacent valley-plain groundwater (VPG) in a tectonic suture zone. The evaluation used a ternary natural-tracer-based end-member mixing analysis (EMMA). With this purpose, VPG and three end-member water samples of plain precipitation (PP), mountain-front recharge (MFR), and mountain-block recharge (MBR) were collected and analyzed for stable isotopic compositions (δ2H and δ18O) and chemical concentrations (electrical conductivity (EC) and Cl−). After evaluation, Cl− is deemed unsuitable for EMMA in this study, and the contribution fractions of respective end members derived by the δ18O–EC pair are similar to those derived by the δ2H–EC pair. EMMA results indicate that the MC, including MFR and MBR, contributes at least 70% (679 × 106 m3 water volume) of the VPG, significantly greater than the approximately 30% of PP contribution, and greater than the 20–50% in equivalent humid regions worldwide. The large MC is attributable to highly fractured strata and the steep topography of studied catchments caused by active tectonism. Furthermore, the contribution fractions derived by EMMA reflect the unique hydrogeological conditions in the respective study sub-regions. A region with a large MBR fraction is indicative of active lateral groundwater flow as a result of highly fractured strata in montane catchments. On the other hand, a region characterized by a large MFR fraction may possess high-permeability stream beds or high stream gradients. Those hydrogeological implications are helpful for water resource management and protection authorities of the studied regions.

Assessment of the Influence of Rainfall and River Discharge on Sediment Yield in the Upper Tana Catchment in Kenya

Sediment yield in the Upper Tana Basin in Kenya has implications on the sustainability of Hydro-Electric Power (HEP) dams and water resources development projects. Therefore, a study was undertaken in the basin to establish the extent to which rainfall and river discharges influence the sediment yield in the catchment. The study was based on hydrological data obtained from the Water Resources Management Authority (WARMA) and Kenya Meteorological Department (KMD). The river discharge data was obtained from three RGS Maragua (4BE01), Gura (4AD01) and Tana Sagana (4BC02) and rainfall data was obtained from Sagana Fish Farm and Nyeri Ministry of Works for the of period 1960-2013.The study also applied the Soil Water Assessment Tool (SWAT) Model to determine the extent to which the model can be used to simulate streamflow and sediment yield in the basin. The results of the study showed that there is a significant variability in streamflow and sediment yield in the Upper Tana Basin. In the period between 1960 and 2015, the mean total annual river discharge of Tana Sagana was 128 m3s-1, and the maximum and minimum river discharges were 29.94 m3s-1 and 3.15 m3s-1, respectively. There was an indication of increasing trend in rainfall and subsequently sediment yield in the basin, which may be attributed to alteration of land use and climatic change. The results showed that SWAT model was quite good in simulating the variability of river discharge. The analysis revealed a poor relationship between sediment yield and rainfall. However, the relationship between rainfall and stream flow was strong with r value of 0.9 which is significant at p=0.05. Relationship between simulated and observed river discharge had a R2 of 0.442, r of 0.665 and NSE of -89.43. The relationship between simulated and observed sediment yield had a R2 of 0.733, r of 0.86 and NSE of 0.69. The results of this study showed that SWAT model can be used to predict sediment yield in the Upper Tana catchment. The model had good performance when daily rainfall, stream flow and sediment yield data were used. Thus, the model can be used to establish the relationship between rainfall, discharge, and sediment yield in a highly human-impacted tropical catchment area. The study puts also forward various recommendations on land and water resources management in the basin.

Modeling the Impacts of Land Cover Changes on Stream Flow Response in Thiba River Basin in Kenya

Soil and Water Assessment Tool (SWAT) was used to model the impacts of land cover changes on stream flow regime in the Thiba River basin covering a surface area of 1648 km2 in central region of Kenya. The basin is characterized by intensive agricultural activities including the largest rice irrigation scheme in Kenya. A study was undertaken to test the capability of the model in predicting stream flow response under changing land use conditions in a typical tropical river basin. Classified land use maps of 1984, 2004 and 2014 were analyzed to investigate land use changes in the basin. Field based survey, National Irrigation Board (NIB), Kenya Meteorological Department and Water Resources Management Authority (WRMA) provided hydro-meteorological data for the study. The results of the study shows that forest cover in the Thiba River basin has decreased by 18.39 % between 1984 and 2014 while area under rice cultivation increased by 9.38 % in the same period. The SWAT Model results showed that there is a significant relationship between the observed and simulated average monthly stream flows in the Thiba River Basin. The Nash-Sutcliffe Efficiency (NSE) and coefficient of determination (R²) during calibration period (1983-1988) were 0.82 and 0.9, respectively, while for the validation period (1989-1993) they were 0.79 and 0.87, respectively. The average monthly stream flows increased by 6.01 m³/s during the wet season and decreased by 1.92 m³/s during the dry season. The changes in stream flow were attributed to the land cover change and rainfall variability. About 35% of dry season flow and 3% of wet season flow was found to have been directly abstracted from the Thiba River. The study recommends that the basin stakeholders should optimize utilization of abstracted water to avert future catastrophic stream flow fluctuations, possibly flooding during the wet season and low or dry riverbeds during the dry months. The high water demand in the dry months can be met by constructing water storage reservoirs to harvest the high runoff during the wet months. Also, it's important that further research on impact of climate change be conducted to better understand the relationship between catchment hydrology and climate change.

Evaluating the Relative Importance of Groundwater Recharge Sources in a Subtropical Alluvial Plain Using Tracer-Based Ternary End Member Mixing Analysis (EMMA)

In Taiwan’s humid climate, proximal fan groundwater (PFG) is mainly sourced from local precipitation (LP), mountain front recharge (MFR), and mountain block recharge (MBR). This study evaluates the relative importance of the above sources’ respective contributions to the PFG of the Langyang alluvial plain (LAP), northeastern Taiwan. To this end, we first identify stable isotopic characteristics of these target waters and evaluate the hydrological relations among them. Further, we employ ternary end member mixing analysis (EMMA) based on δ18O and electrical conductivity to semi-quantitatively calculate contributing fractions and amounts of water for respective LP, MFR, and MBR end members. EMMA results indicate that the respective contribution fractions of LP, MFR, and MBR to PFG at the LAP are approximately 28, 60, and 12 %, respectively. Further, we employ the obtained contribution fractions to understand the corresponding water amounts of each end-member contributed to PFG. In total, 325 × 106 m3 of water recharges PFG annually; of which, 226 × 106 m3/yr. is from MFR, 76 × 106 m3/yr. from LP, and 23 × 106 m3/yr. from MBR. MFR is clearly the greatest source of water at the LAP and local water resource management and protection authorities should concentrate their energies on this important contributor to groundwater. To keep these results in context, limitations to the EMMA approach are evaluated in the text.

Degradation of Lake Ziway, Ethiopia: A study of the environmental perceptions of school students

AbstractLake Ziway in Ethiopia is a freshwater lake supporting multitude uses, including irrigation, fishing, water supply and recreation. However, the lake is being degraded primarily because of various land‐ and water‐use activities in its watershed. Recognizing these human impacts on the lake's water quality and quantity, the perceptions of school students were surveyed under the belief that the future of the lake is largely dependent on this younger generation. The goal of this study was to better understand how students actually recognize the extent to which various human activities impact the water quantity and quality of Lake Ziway. As major stakeholders in their communities, the perceptions of school students from four high schools regarding the changes to the lake over time were investigated. Students were contacted by purposive sampling, based on criteria of student academic performances, and their proximity to the lake. Their perceptions were studied on the basis of an interview survey. The majority of students indicated that high levels of human activities, especially water abstractions and water pollution, were the main lake impacts. Students believe there is a lack of sustainable utilization and protection of the lake. They suggested coordinated activities among all lake stakeholders in the participation and decision‐making process to properly manage the lake. Provision of awareness to both local administrations and local communities, concern for establishing an appropriate regulatory body and allocating a sufficient budget, and strict controls on flower farm practices in the lakeshore, also was considered to be of high priority as a means of conserving the sustainability of the lake. The result derived from this survey has important implications for facilitating improved school curricula, and for federal, regional and district level water resource management authorities, in setting priorities and developing policies for the sustainability of Lake Ziway.

Impact of rainfall variability on groundwater levels in Ruiru municipality, Kenya

Groundwater accounts for the largest fresh water resources in the world. However, there has been limited exploitation of this vital resource in many areas. Where groundwater resources have been utilised, they have been over-exploited, polluted, wasted and mismanaged. In Ruiru municipality, groundwater is a major component of the water supply, contributing about 70% of the water demand. Rising population numbers and industrial development have led to a high water demand, increased water scarcity and more reliance on ground water. Assessing the effect of rainfall variability on groundwater levels of boreholes in Ruiru municipality will help in assessing the sustainability of groundwater resources in the area. Groundwater levels were measured using a dipper and spatial locations of the boreholes were established and mapped using GIS. Rainfall data was collected from the Kenya Meteorological Department and the Water Resources Management Authority. The water table fluctuation method was used to estimate recharge. There was an impact of rainfall variability on groundwater levels. The results showed a decline in groundwater levels during low rainfall periods. The rainfall variability, caused by climate change, brought about prolonged droughts and low recharge in the area. Climate change should be mitigated to cap the decline in groundwater and abstraction controlled to ensure that groundwater resources are managed properly to avoid depletion.

Simulation of organic carbon loading using MIKE 11 model: a case of River Nzoia, Kenya

River Nzoia is the largest river draining into the Kenyan portion of Lake Victoria. This river receives both point sources of pollution from industrial and municipal wastes, and non-point sources from agricultural runoff in the catchment. The objective of this study was to simulate dissolved oxygen (DO) and biochemical oxygen demand (BOD) of the middle section of River Nzoia using MIKE 11 model. The model was calibrated using discharge and water quality data for 2009 and validated with March–April 2013 data. The model performance was good with coefficient of determination (R2) values of between 0.845 and 0.995, Nash–Sutcliffe efficiency values of between 0.748 and 0.993 and percent bias of less than 10 for both calibration and validation of electrical conductivity (EC), DO and BOD. EC and BOD values were lower for April compared to March which could be attributed to dilution during high flows. DO values were above the recommended minimum level of 4 mg/l in all the sections of the river in the wet period but some sections had lower than 4 mg/l during low flow period. The government agencies such as Water Resources Management Authority and National Environment Management Authority should enforce the effluent standards to ensure that industries and wastewater treatment plants adhere to the maximum allowable limit for BOD and also improve their treatment efficiencies of wastewater plants so as to improve the quality of River Nzoia which is important in the overall management of the Lake Victoria basin.

A Microeconomic Perspective on Water Resources Management: Analyzing the Effects on Optimal Land Rents Along a River Basin

Water scarcity is becoming an increasingly relevant issue in many regions of the world as demand for water continues to grow. As a result, the need for finding measures that efficiently allocate increasingly scarce water resources has become a primary topic on the agendas of many water resource management authorities. This paper presents an innovative approach that provides further insight into the connection between hydrological, environmental, and economic aspects along a river basin. In short, it analyzes how land rents along a river basin are affected by managing water pollution along a river basin, given certain hydrological characteristics of the river basin. Results show that, without the implementation of a water management system to control water quality, the negative external effects of upstream water discharges on downstream locations can be internalized through a decrease in downstream land rents. However, the analysis presented in this paper also reveals that it is not only the absence or the presence of a water management system that has a significant impact on the real estate market along the river basin. Moreover, the market outcome also varies with the type of water resources management system implemented.