Intergrated Water Resources Management

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Analysis of spatial and temporal drought variability in a tropical river basin using Palmer Drought Severity Index (PDSI)
(Acadamic Journals, 2017-08-31) Wambua, Raphael; Mutua, Benedict; Raude, James
Analysis of spatial and temporal drought variability in the upper Tana River basin using Palmer Drought Severity Index (PDSI) was conducted. The drought is critical for formulation of mitigation measures in the river basin. A monthly temporal and 90-m spatial resolution was applied. This was achieved within ArcGIS environment. Climatic data for 1970 to 2010 was used for computation of the PDSI while the missing data sets were filled using Artificial Neural Networks (ANNs). The results of PDSI for dry and wet seasons at meteorological stations indicate that the time series plots for the PDSI values for dry season are generally lower than those for the wet seasons. The PDSI values for meteorological stations located at the lower elevation of the basin are lower than those located at higher elevation. On the other hand, spatially distributed drought severity based on PDSI show that the ranges of maximum and minimum drought severity values in 1970 are -0.868 to -0.804 and -0.675 to -0.610 respectively. These values of drought severity occur respectively in the north-western and south-eastern areas of the basin. PDSI values increased from the range -0.675 to -0.610 in 1970 and from -1.087 to 0.957 in 2010 for the north-eastern areas of the upper basin. The south eastern areas of the basin are more prone to drought risks than north-western parts. Use of the PDSI reflects the spatial heterogeneity and temporal variability of drought across the basin. The drought assessment offer technical approach for comprehensive understanding of drought for effective drought-induced disaster mitigation and its management, with a view to reducing adverse effects on livelihoods.
Characterization of anthropogenic activities influencing surface water quality along molo river ecological system, Kenya
(Ethiopian Journal of Environmental Studies & Management, 2017-12-13) Ogendi, G.M.; Moturi, W.M.; Kibitok, N.K.
Surface water is progressively subjected to stress as a result of anthropogenic activities. Systematic observation and characterization of anthropogenic activities along Molo River was done in 2014 to evaluate their effects on surface water quality. Portable GPS receiver was used to identify geographic locations of 23 sites purposively selected; based on their relative positions to the point of anthropogenic activities and included a reference located in the upper reaches. An observation schedule was used to collect data during dry and rainy-season. Chemical parameters were determined by spectrophotometry using standard methods and physical parameters measured in-situ using Wisenschafflich-Technische Werkstätten and pen type Dist 3 Model Meter probes. Data were analyzed using descriptive and inferential statistics. The frequency of occurrence and percentages were computed. Analysis of variance (ANOVA) was used to analyze mean concentrations of various physical-chemical parameters and various sampling occasions. Maximum NO2 was (45.42±3.4 mg∙L−1), NO3 (44.1±0.1 mg∙L−1), SRP 50.25±0.4, DO2 was 0.3±0.0 mg∙L−1, conductivity (616±1.4 μS/cm), and TDS 405.8±8.1 mg∙L−1 while NH4-N 79.69±1.2 mg∙L−1, TN 109.36±09 mg∙L−1, pH was 12.525±8.0 and T ºC 21.4±0.2 ºC. Mean TP was 13.21±1.78 mgL-1 and 2.43±1.70 mgL-1 highly significant at p<0.05 i.e. p= 0.0001. Results indicate that there were significant differences in the means of NO2-N, NO3-N, NH4-N, TN, DO, EC, T°C, and TDS (p=0.0038, 0.0001, 0.0001, 0.0001, 0.0001, 0.0001, 0.0021, and 0.0001) respectively. Observed activities comprised urban-construction/dumping of waste adjacent to riparian-buffer-zones recording 18.4%, domestic animals watered at the river 28.09%, people crossing river using vehicle/motorbikes and/or on-foot 39.2%, children playing in the river 12.9%,water abstraction 11.9%, sand harvesting/quarrying 0.16%, septic tanks-leaks, waste discharged into the river 4% and Washing linen 4.4%.. Washing vehicle/cars/motorbike was highest at the site denoted M3, recording 265 observations. Frequency and intensity of human activities closely relate the results on physical-chemical parameters, interference from direct human activity than natural phenomenon explains the finding. The river water is unsuitable for human consumption.
Characterization of temporal and spatial drought risk events using surface water supply index (SWSI) in a tropical river basin
(MEDCRAVE, 2017-02-16) Wambua, Raphael M; Mutua, Benedict M; Raude, James M
In the present study, temporal and spatial drought-risk events are characterized using a Modified Surface Water Supply Index (SWSI) for upper Tana River basin, located in tropics, Kenya. Forty years (1970-2010) hydro-meteorological data for low, lower middle, middle and high elevations at eight hydro-metric stations was used to characterize spatial and temporal distribution of drought. The spatial drought distribution is obtained via interpolation of hydro-metric stations data using Kriging interpolation technique embedded ArcGIS 10.1 was used. The drought trends were analyzed using a non-parametric Mann-Kendall trend test. The results show that south-eastern parts of the basin are the most drought-prone areas at different drought severities and frequencies. Drought severity classes ranged from 1.69-2.22 to 3.39-4.17 and 2.68-3.21 to 4.37-4.96 in 1970 and 2010 respectively across the river basin. The south-western parts of the basin exhibited highest drought frequency ranging from 10.61 to 13.16 while the north-western areas gave frequency values ranging from 3.74 to 6.29. The findings of the study are applicable in Early Drought Warning Systems, prioritized water resources planning and management.
Composition and design of vegetative filter strips instrumental in improving water quality by mass reduction of suspended sediment, nutrients and Escherichia coli in overland flows in eastern escarpment of Mau Forest, Njoro River Watershed, Kenya
(Springer Link, 2016-06-13) Olilo, Casianes; Onyando, Jack; Moturi, Wilkister; Muia, Wairimu; Roegner, Amber; Ogari, Zachary; Ombui, P.; Shivoga, William
This study assessed the effect of vegetative filter strip (VFS) in removal of suspended sediment (SS), total nitrogen, total phosphorus and Escherichia coli (E. coli) in overland flow to improve receiving water quality standards. Four and half kilograms of cowpat manure was applied to the model pasture 14 m beyond the edge of vegetated filter strip (VFS) comprising 10-m Napier grass draining into 20-m Kikuyu grass (VFS II), 10-m Kikuyu grass draining into 20-m Napier grass (VFS III) and native grass mixture of Couch–Buffel (VFS I-control). Overland flow water samples were collected from the sites at positions 0, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25 and 30 m along the length of VFSs. E. coli removal by Napier grass VFS was on the order of log unit, which provided an important level of protection and reduced surface-flow concentrations of E. coli to below the 200 (CFU 100 mL−1) recommended water quality standards, but not for nutrients and SS. The Napier grass showed highest efficiency (99.6 %), thus outperforming both Kikuyu grass (85.8 %) and Couch–Buffel grasses VFS (67.9 ± 4.2 %) in removing E. coli from overland flow. The low-level efficiency of native Couch–Buffel grasses in reducing E. coli in overland flow was because of preferential flow. Composition and design of VFS was instrumental and could be applied with a high potential of contracting the uncertainty in improving water quality standards through mass reduction of SS, nutrients and E. coli load in watersheds.
Development of a non-linear integrated drought index (NDI) for managing drought and water resources forecasting in the upper Tana river basin-Kenya
(2020) Wambua, Raphael M.
This article uses the non-linear integrated drought index (NDI) for managing drought and water resources forecasting in a tropical river basin. The NDI was formulated using principal component analysis (PCA). The NDI used hydro-meteorological data and forecasted using recursive multi-step neural networks. In this article, drought forecasting and projection is adopted for planning ahead for mitigation and for the adaptation of adverse effects of droughts and food insecurity in the river basin. Results that forecasting ability of NDI model using ANNs decreased with increase in lead time. The formulated NDI as a tool for projecting into the future.
Economic efficiency of water use in the small scale irrigation systems used in vegetables production in Koulikoro and Mopti regions, Mali
(The Society of Agricultural Professionals, 2018-07-27) Abdoulah Mamary, Kane; Langat, Jackson; Lagat, Prof; TEME, Pr; Wamuyu, Samuel; SIJALI, Vincent
Malian households depend, in majority, on rain-fed agriculture for their food production. Overreliance on rain-fed agriculture limits the production output due to unreliable rainfall in the country. To mitigate this, the government has invested in rehabilitation of irrigation schemes to reduce dependence on rainfall. Through appropriate irrigation technologies and improved agronomic management practices agricultural productivity will be increased. This study determines the contribution of different irrigation systems to produce vegetables on household welfare in rural communities. The objective of the study was to contribute to improved livelihood of smallholder farmers in rural areas by use of irrigation systems in vegetables production. Three localities corresponding to two specific climatic regions favorable to vegetable crops production in Mali (Baguineda, Kati, Koulikoro region and Mopti region) was the study area. This study was guided by the production theory. Primary data was collected from 273 farmers selected proportionately from four wards (Fanafiecoura and Tieman, in Koulikoro region and Mopti and Dialango, in Mopti region) using face-to-face interviews. Secondary data from literature reviews was also used. Descriptive statistics and DEA functions were used for analysis. The Statistical Package for Social Scientists (SPSS), Stata and Excel programs were used for analysis. This study found that the irrigation systems as used in production of the three main crops to be characterized by inefficiency. Drip and sprinkling irrigation systems was relatively more economically efficient as compared with Californian system. The use of drip, sprinkling and Californian irrigation systems lead to greater benefits as compared to costs. The excess benefit (compared to costs) is realized more with drip followed by sprinkling and the third being California irrigation system. This study recommends more training and capacity building to the farmers in the study area with an aim of reducing their levels of inefficiencies in horticultural crop production. Farmers should be supported to adopt the use of drip, sprinkling and Californian irrigation systems which lead to greater benefits as compared to costs. Drip, sprinkling and Californian irrigation systems present a good opportunity for superior technical efficiency in vegetable production. These irrigation technologies should be promoted.
Effects of Population Growth on Urban Extent and Supply of Water and Sanitation: Case of Nakuru Municipality, Kenya
(Journal of Environmental Management, 2019) Muoria, Elizabeth; Moturi, Wilkister; Eshiamwata, George
Urbanization causes changes in social and environmental conditions with most of these changes impacting on the efficient provision of essential services such as water and sanitation. Nakuru Municipality was observed to be the fastest growing urban area in East and Central Africa. Research on patterns and trends of urban and population increase and their implication on water service provision and sanitation in urban Nakuru is very scanty. This paper presents findings from an assessment of the effects of population growth between 1999 and 2017 on urban extent and supply of water and sewage reticulation in Nakuru municipality and surrounding peri-urban areas. Data was collected through remote sensing and administration of questionnaires to urban Nakuru residents and key informants from NAWASSCO respectively to elicit information on the water supply network and sewerage reticulation in Nakuru municipality for the period 1989-2014. Geographic Information System (GIS) was used to analyze the data on time series. The results indicate that the population of Nakuru municipality and surrounding peri-urban areas has increased by 56.8% whereas that of built-up area has increased by 182.5% in the same period through densification of the urban core and expansion to the peri-urban areas characterized by urban sprawl. The water supply network and sewerage reticulation increased by 236km and 89km respectively within Nakuru municipality. The analysis of the maps shows that water supply network and sewerage reticulation are concentrated in the area around the urban core with very little spread. This means that the residents on the outskirts of Nakuru Municipality are not well served by the water supply network and sewerage reticulation. The study recommends involvement of all stakeholders in urban planning and in the water sector in order to increase water supply network and sewerage reticulation coverage both in the urban and peri-urban areas.
Effects of supplemental irrigation on yield, water use efficiency and nitrogen use efficiency of potato grown in mollic Andosols
(Springer Nature, 2021-08-18) Satognon, Felix; Owido, Seth F. O.; Lelei, Joyce J.
Low soil fertility and reduced seasonal rainfall contribute to low potato (Solanum tuberosum L.) yield in Kenya. Nitrogen (N) deficiency is the major problem facing by the smallholder farmers of Kenya due to lack of fallow. Hence an introduction of supplemental irrigation with an adequate application of this nutrient could increase potato yield. The objective of this study was to determine the effects of supplemental irrigation and N-fertilisation on potato tuber yield, water use efficiency (WUE) and nitrogen use efficiency (NUE). The experiment was conducted in Nakuru County, Kenya for two seasons. The experimental soils are classified as mollic Andosols. The treatments comprised two irrigation treatments of full supplemental irrigation (FI) and rainfed production (RF) and four N levels of four N levels of 0 (N0), 60 (N1), 90 (N2) and 130 kg N/ha (N3).ResultsThe results showed that total tuber yield, marketable tuber yield and NUE were significantly (P < 0.001) affected by irrigation × N-fertilisation while WUE was only affected (P < 0.001) by N-fertilisation. The highest total tuber yield, 58.28 tonnes/hectare (t/ha), was recorded under FI combined with N3. Treatment FI significantly increased marketable tuber yield by approximately 125.58% in all N treatments compared to RF. The highest NUE of potato (236.44 kg/kg of N) was obtained under FI combined with N3 but not significantly different from the NUE of potato obtained under FI with N2. N-fertilisation N3 produced the highest WUE of 14.24 kg/m3. Significant correlation was obtained between tuber yield and number of tubers/plant (r = 0.75, P < 0.001), NUE (r = 0.95, P < 0.001) and WUE (r = 0.72, P < 0.001).ConclusionHigh potato yield and marketable tuber yield can be achieved in mollic Andosols when water deficits of the growing season are eliminated with supplemental irrigation and an application of 130 kg N/ha.
Hydrogeophysical Characterization of a Weathered-Fractured Aquifer System: A Case Study of Olbanita, Lower Baringo Basin, Kenya Rift
(Scientific Research, 2019-11) Sosi, Benjamin; Barongo, Justus; Getabu, Albert; Maobe, Samson
Groundwater yields in the Kenya Rift are highly unsustainable owing to geological variability. In this study, field hydraulic characterization was performed by using geo-electric approaches. The relations between electrical–hydraulic (eh) conductivities were modeled hypothetically and calibrated empirically. Correlations were based on the stochastic models and field-scale hydraulic parameters were contingent on pore-level parameters. By considering variation in pore-size distributions over eh conduction interval, the relations were scaled-up for use at aquifer-level. Material-level electrical conductivities were determined by using Vertical Electrical Survey and hydraulic conductivities by analyzing aquifer tests of eight boreholes in the Olbanita aquifer located in Kenya rift. VES datasets were inverted by using the computer code IP2Win. The main result is that InT = 0.537(1nFa) + 3.695, the positive gradient indicating eh conduction through pore-surface networks and a proxy of weathered and clayey materials. An inverse (1/F-K) correlation is observed. Hydraulic parameters determined using such approaches may possibly contribute significantly towards sustainable yield management and planning of groundwater resources.
Integrating MFT-qPCR techniques in constructed wetland faecal bacterial purification monitoring; a case of a typical tropical hybrid constructed wetland system
(IWA Publishing, 2018-11-14) Omondi, Donde Oscar; Wairimu, Muia Anastasia; Maingi, Makindi Stanley; Otieno, Onyango Godfrey; Jepkorir, Kibet Caroline; Okoth, Ogalo Joseph; Bangding, Xiao
The sanitation control of pathogens in the tropical effluents needs much more attention to ensure ecosystem health integrity and the safety of human health. The common use of chemicals in achieving this in wastewater treatment has remained unsustainable due to much health concern. Indeed, based on the numerous challenges associated with faecal pathogenic bacteria in wastewaters, the focus is now on achieving higher purification efficiencies in the elimination of the human pathogens from wastewater through eco-sustainable systems such as constructed wetlands (CWs). Hence, the need to explore the application of constructed wetlands in wastewater treatment under specific local environmental conditions for accurate understanding and improved treatment efficiency. This study therefore aimed at monitoring constructed wetlands faecal bacteria purification efficiency through integrated non-molecular membrane filtration technique and molecular quantitative polymerase chain reaction (MFT-qPCR) technique. The results showed some shortfall in the treatment system and also proved that integrating MFT-qPCR in faecal bacterial purification monitoring within a constructed wetland system provides a more accurate and reliable outcome. Additionally, the wetland purification efficiency was low (<80%) with the dissolved oxygen posing the strongest influence on faecal pathogenic bacterial purification trend across the wetland. Hence, the need to regularly carry out dredging and macrophyte harvesting as well as the use of holistic and more integrative approaches such as MFT-qPCR in managing and monitoring the performance of CWs in faecal pathogen eradication for improved CWs purification efficiency.
Longitudinal trends in macroinvertebrate functional feeding groups in a high-altitude tropical stream (a case study of Gura River)
(Egerton University, 2021-08-31) Benjamin, Joshua
Functional feeding groups (FFGs) classification of aquatic macroinvertebrates is an important tool that enhance the knowledge of trophic dynamics in tropical streams by assigning the benthic community into trophic guilds.The current study aimed at determining the longitudinal trends in macroinvertebrate functional feeding groups in Gura River. Macroinvertebrates were collected between November and December 2018 in seven sites along the Gura River from an altitude of 2977 to 1547 m a.s.l. At the same time, selected physical chemical variable were measured in situ at every site. Dissolved oxygen concentration (mgL-1), water temperature (oC), electrical conductivity (µScm-1), pH and turbidity (NTU) had a significant difference among the sites (p <0.05). Most of the nitrates and phosphate nutrients had a significant difference among sampled sites (p <0.05) except NO2-N as demonstrated by analysis of variance (one-way ANOVA, F (6,14) = 2, p=0.085).A total of 4016 macroinvertebrates specimen were collected belonging to 9 orders and 28 families and assigned into 5 respective FFGs. Overall, Scrapers, dominated by Heptageniidae (Afronurus) had the high relative proportion of FFGs in all the sites with a proportion of 42%. Shredders and Predators were the least represented functional feeding groups with proportions of 6% and 3% respectively. This study is crucial in the Gura River because FFGs can be used as an indicator of aquatic ecosystems change in case there is alteration of ecosystem function due to environmental variables.
Modeling climate variability influence on river regime in upper Njoro catchment, Kenya
(Science Publishing Group, 2020-10-13) Amisi, Edwin O.; Kundu, Peter M.; Wambua, Raphael M.
To establish the effect of climate variability on annual discharge in Upper Njoro Catchment, hybrid models were developed by coupling Soil and Water Assessment Tool and Artificial Neural Networks. Daily surface runoff, lateral flow, and groundwater flow were first simulated with SWAT for the period (1978-1987) using climate variables from Egerton University weather station and LULC of 1978. The daily hydrologic variables simulated without calibration and validation of SWAT and observed discharge data were then used for ANN training, which led to the creation of discharge generation hybrid models for the dry, wet and wetter seasons. SWAT_ANN models generated discharges were compared with observed data and the performance rating were achieved at R2 (0.94, 0.91, 0.92) and NSE (0.89, 0.87, 0.87) for DJFM, AMJJ, and ASON seasons respectively. SUFI-2 algorithm in SWAT-CUP was run separately to compare the performance of SWAT with that of SWAT_ANN. SWAT-CUP sensitivity analysis revealed satisfactory values of both the p-factor (0.61) and the r-factor (0.69). Calibration and validation of monthly streamflow were realized at R2 (0.86 and 0.78) and NSE (0.83 and 0.74). The results showed that coupling SWAT and ANN improved flow prediction. Further, the potential of the SWAT_ANN modeling approach to separate the influence of climate variability on river regime from the effect of LULC was evaluated by comparing trends in the differences between observed and SWAT_ANN simulated monthly streamflow with trends of the quantified LULC changes. The findings provided sufficient evidence that the SWAT_ANN modeling approach was reliable and could also be applied to detect changes in LULC.
Nutrient removal efficiency by floating macrophytes; Lemna minor and Azolla pinnata in a constructed wetland
(GJESM Publisher, 2019-07-13) Muvea, F. M.; Ogendi, G. M.; Omondi, S. O.
The use of constructed wetlands for purifying pre-treated wastewater is a cost effective technology that has been found to be more appropriate for many developing countries. The technology is also environmentally friendly with the wetlands being habitats for many water birds and other aquatic organisms. This study assessed nutrient removal efficiency of two floating macrophytes (Lemna minor and Azolla pinnata). The data generated was analyzed using both descriptive and inferential statistics. The significance level was maintained at 0.05. The results showed that the wastewater physicochemical parameters did not vary during the study period. The concentrations of nitrites and nitrates increased over the experimental period in all the treatments (Azolla pinnata, Lemna minor and control), and the increase between the sampling occasions was statistically significant for the two nutrients (Nitrates: F=24.78, P= 0.00; Nitrates: F=198.26, P= 0.00). To the contrary, in all the treatments the concentrations of ammonia, total phosphorous, soluble reactive phosphorous and total nitrogen, decreased over the experimental period. The decrease in concentration for these nutrients between the sampling occasions was statistically significant (ammonia: F=195.57, p= 0.00; total phosphorous: F= 56.50, p= 0.00; soluble reactive phosphorous: F= 37.11, p= 0.00; total phosphorous: F= 104.025, p= 0.00). Azolla pinnata proved to be better than Lemna minor in the uptake of the nutrients particularly for the soluble reactive phosphorous (F= 35.18, P= 0.044). We conclude that the two macrophytes are good for wastewater treatment. It is recommended introduction and/or multiplication of Azolla pinnata in the constructed wetlands meant for wastewater treatment especially within the tropics.
SIMULATION OF CROP WATER PRODUCTIVITY AND YIELD RESPONSE OF POTATOES UNDER SUBSURFACE DRIP IRRIGATION SYSTEM USING THE AQUACROP MODEL | Journal of Engineering in Agriculture and the Environment
(Journal of Engineering In Agriculture And The Environment, 2023-05-20)
The need for increased food production by applying low water quantity is pausing more challenges to farmers. The production of Irish Potatoes in Kenya in arid and semi-arid areas is challenging for most farmers due to low yields. A field experiment was conducted at Egerton University during the 2021-2022 dry season. The effect of deficit subsurface drip Irrigation allied with superabsorbent polymer soil amendment on growth parameters and yield of potatoes was evaluated. Twelve treatments composed of three water application levels 70%IL, 85%IL,100%IL and four super absorbent polymer (SAP) application rates No SAP, 6 kg/ha, 10 kg/ha, and 14kg/ha laid in factorial experimental design were applied in December 2021 to May 202 season. Irrigation was undertaken when the allowable water depletion reached 50%. The AquaCrop model was applied to predict soil water content, biomass, canopy cover, dry yield, and water productivity (WP). The 100% water application level with 0kg/ha SAP was used in model calibration, whereas the remaining was used to validate the model. The model simulated compared with observed canopy cover, biomass and WP produced a good performance with R2 range of 0.86 to 0.98, root mean square error (RMSE) of 10.6%, NSE of 0.9, and Wilmot's degree of agreement of 0.98. However, the model underestimated the water content due to the application of SAP in the soil. The findings indicated that the combined effect of SAP and subsurface drip resulted in increased yield in deficit water application. The calibrated model was successfully applied in simulating WP and yield response of the three water treatments for No SAP, 6 kg/ha SAP, 10 kg/ha SAP, and 14 kg/ha SAP.
Some aspects of Oreochromis niloticus baringoensis (Trewavas, 1983) fishery assessment and influence of selected water quality parameters in the hot springs of Lorwai Swamp, Baringo, Kenya
(Egerton University, 2019-12-05) Adamba, Stephanie Wangare Kamau
Water quality has been documented to affect the biology and well-being of fish. This study therefore investigated some aspects of Oreochromis niloticus baringoensis (Trewavas, 1983) fishery assessment and the influence of selected water quality parameters in two hot springs draining into Lorwai Swamp; Lake Bogoria Spa spring and Chelaba spring between the months of July and August, 2018. A total of 445 fish were collected; 244 from Lake Bogoria Spa spring and 201 from Chelaba spring using a seine net. Length Weight Relationship (LWR) was determined using Le Cren’s equation; W=aTLb and Fulton’s condition factor (k) determined using Ricker’s equation; 100W/L3. LWR results indicated an isometric growth for fish from both springs. The mean (± SD) k values for fish in Lake Bogoria Spa spring were 2.02±0.25 for the males, 2.02±0.27 for the females and 2.00±0.26 for both sexes. In Chelaba spring, the mean k values were 2.03±0.21 for the males, 1.97±0.25 for the females and 2.00±0.23 for both sexes. These values indicated that the fish in these hot springs are in a very good condition and healthy status with k values above 1. Some of the selected water quality parameters indicated a positive correlation with the length, weight and Fulton’s condition factor of O. n. baringoensis in the two hot springs.
Stochastic Drought Forecasting Exploration for Water Resources Management in the Upper Tana River Basin, Kenya
(Engineering Science Reference (an imprint of IGI Global), 2015-01) Wambua, Raphael M.; Mutua, Benedict M.; Raude, James M.
This chapter presents the trend of drought as a stochastic natural disaster influenced by the climate variability for the upper Tana River basin in Kenya. Drought frequency, duration and intensity in the upper Tana River basin have been increasing over the years. To develop measures for mitigating impacts of drought, the influencing hydro-meteorological parameters and their interaction are necessary. Drought definitions, fundamental concepts of droughts, classification of droughts, types of drought indices, historical droughts and application of artificial neural networks in analyzing impacts of drought on water resources with special focus on a Kenyan river basin is presented. Gaps for more focused research are identified. Although drought forecasting is very vital in managing key sectors such as water, agriculture and hydro-power generation, drought forecasting techniques in Kenya are limited. There is need therefore to develop an effective drought forecasting tool for on-set detection, classification and drought forecasting. The forecasting is necessary for decision making on matters of drought preparedness and proper water resources planning and management
Suitability of biosolids from university sewage ponds as a substrate for crop production
(Acadamic Journals, 2019-12-31) Otieno, Peter Caleb; Nyalala, Samuel; Wolukau, Joseph
Currently, sewage waste management is a serious environmental problem and one of the major growing concerns for urban areas all over the world. Utilization of biosolids (BS) for crop production may be a sustainable waste management strategy. The present study evaluated the physico-chemical and biological characteristics of biosolids from sewage ponds at Egerton University, Kenya. This was to determine its suitability for crop production. Biosolids were evaluated separately then as mixture with forest soil at rates of 0, 10, 20, 30, 40, 50 and 60% and compared with tea compost (TC) and coco peat (CP) in a completely randomized design experiment with four replications. Data collected included: macro-elements, micro-elements, heavy metals, pH, electrical conductivity (EC), bulk density (BD), water holding capacity and biological properties. Results showed that total organic carbon (0.03%), total organic nitrogen (2.0%) and Molybdenum (22 mg kg-1), in biosolids were significantly (p < 0.05) higher compared with forest soil, but not significantly different from tea compost. For heavy metals, Hg (0.33 mg kg-1), As (5.9 mg kg-1), Cr (31.1mg kg-1), Cd (0.38 mg kg-1), Ni (16.3 mg kg-1) and Zn (127 mg kg-1) were significantly (p < 0.05) higher in biosolids but within the allowable limits according to Environmental Protection Agency (EPA) standards. bulk density (1.2 to 1.5) g cm-3 and pH (5.4 to 5.8) units, but high organic matter (195 to 230) g kg-1, water holding capacity (35 to 42 %) and EC (2.6 to 5.4) µSm-1). For microbial load, total viable count (TVC) and colony forming units (CFU) registered 5 ×10-7 and 6.5×10-7 respectively. However, Escherichia coli, Salmonella sp. and Staphylococcus sp. were not detectable in the fully composted biosolids. Similar trend of these results were subsequently observed in the substrates formed in the mixture of biosolids and forest soil and this provide insight on the potential of biosolids as substrate for crop production and a reliable alternative to soil alone. Key words: Biosolids, forest soil, organic amendment, substrate.
Variation of Human and Domestic Animal’s Activities with Discharge in a High Altitude Tropical Stream, the Njoro River, Kenya
(Egerton J. Sci. & Technol., 2019) C. M., M’Erimba; Chepkorir, J. K.
From ancient times human settlements and cultures thrived along rivervalleys which provided water for domestic use as well as agriculture.aspopulation grew, human activities impacted river valleys as well as affectedwater quality. An investigation was carried out during low (January to March2012) and high (August to October 2012) discharge regimes in the NjoroRiver to establish whether the river’s discharge dictated the visit rate andactivities by people and animals at three sites. The study involved countingof people and animals during the day between 1000–1300hrs that visited theriver, and recording down the activities. The visit rate by people wasstatistically insignificant between low (30.75 ± 5.64 ind. hr-1) and high(20.58 ± 3.41 ind. hr-1) discharges respectively, (t =1.544, d.f = 70, p >0.05). A similar observation was made in mean visit rates by animals(t-value = 0.725, p > 0.05). However, significant differences in the rate ofpeople and animals (pooled data) were evident among the sites during lowand high discharge periods (one-way ANOVA, P < 0.001). More menfetched water at the most downstream site than women during both dischargeregimes, and the opposite was evident at the first site. It is concluded thatdischarge did not influence significantly the visit rates and other factors thatare site specific should be explored.Disturbances in the Njoro River are ofpress type and requires interventionfor themanagementof this river.
Wastewater Management Techniques: A Review of Advancement on the Appropriate Wastewater Treatment Principles for Sustainability
(Macrothink institute, 2017-03-11) Donde, Oscar Omondi
Water is an essential resource that is required to sustain life. Its availability has to be adequate, safe and easily accessible. Current trends in climate change and rise in human population has compromised water adequacy, availability and safety. Wastewater managers around the world have the responsibility to ensure that the effluent that is eventually released into the environment does not degrade the quality of the recipient water bodies. Attaining sustainability in wastewater management is top in the of Sustainable Development Goals’ Agenda. All in all, the realization of a more sustainable wastewater management will require a highly holistic and balanced approach in evaluating a particular management strategy's overall sustainability. Promoting the use of safe, affordable and adequately available wastewater treatment techniques is a step towards wastewater management for sustainability. This review paper therefore discusses some of the currently known and emerging wastewater management techniques that are considered essential in attaining sustainability in water resource management.

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