Thomas Atta-Darkwa | University of Energy and Natural Resources, Sunyani (original) (raw)

Papers by Thomas Atta-Darkwa

Global Journal of Biology, Agriculture & Health Sciences, 2013

The harsh climate, shallow and erodible soils of low fertility uplands have led to farmers extend... more The harsh climate, shallow and erodible soils of low fertility uplands have led to farmers extending their cultivable areas to wetlands for optimal crop production since these systems have the potential for irrigation in the dry season. Inland valleys have been cited as having high potential for development of rice-based, smallholder farming systems at the village level, due to their specific hydrological conditions and relatively high soil fertility. This paper applies a 3D groundwater flow model, PM-WIN MODFLOW to simulate the groundwater heights of the two layered alluvial aquifer of the Besease Inland Valley Bottom. Groundwater recharge estimates from the watertable fluctuation method was used as the recharge input into the model. The results showed that groundwater levels ranged from 259.10-259.97 m in the wet season and 258.19-258.86 m in the dry season for the simulation period. It also exhibited a form of interaction between the inland valley wetland and the bordering Oda River which varied over time depending on the river stage. The values for storage from the model were substantial and indicated the temporal variability in the watertable with continuous movement of water to and from storage over an annual cycle. Sensitivity analysis was performed, and model outputs were found to be highly sensitive to the catchment parameters such as horizontal hydraulic conductivity, specific yield and specific storage. The model helps to unravel the relationship between recurrent spatial and temporal patterns of watertable response within the inland valley bottom and their controlling factors.

Journal of Forestry Research, Apr 28, 2022

physical and biological properties. In this regard, the use of prescribed burning as a management... more physical and biological properties. In this regard, the use of prescribed burning as a management tool to reduce the fuel load is highly recommended due to its low intensity and limited soil heating. Furthermore, the use of prescribed fires to manage fuel loads is critically needed in the light of current global warming as it will help prevent increased wildfire incidences. This review provides information on the impact of forest fires on soil properties, a key feature in the maintenance of healthy ecosystems. In addition, the review should prompt comprehensive soil and forest management regimes to limit soil disturbance and restore fire-disturbed soil ecosystems.

International journal of water resources and environmental engineering, Aug 31, 2016

The shapes and forms of piezometric hydrographs arising from the recharging and discharging of un... more The shapes and forms of piezometric hydrographs arising from the recharging and discharging of unconfined aquifers offer a hydrological tool for the classifications of inland valley bottoms in Ghana for crop production. A two-year measured water table fluctuations at Besease wetlands were plotted on a reference scale of time in months on the x-axis and hydraulic head on the y-axis. The water table fluctuation method was used to evaluate the seasonal and annual variations in the water level rise and to estimate the groundwater recharge. The monthly slopes segment of the water table fluctuations were used as a base for the classification of the heads. Results from the study showed that the estimated recharge for the study area ranged from 133 to 467 mm for the fourteen (14) piezometers, representing 9 to 31% of 2009 annual rainfall and 47.6 to 427.9 mm in 2010 representing 4 to 34% of the annual rainfall. The Results also showed that most of the piezometers had their monthly slopes dominated by the acute segment followed by the obtuse segment, flat segment and right-angled segment in that order. It can be inferred that most of the piezometric areas dominated by acute forms become relatively dry during the dry season; however, these areas may still have some water to support crops. The hydrograph representation of the monthly slopes were employed to classify the studied Inland Valley Bottoms into three hydrological regimes as a management tool for developing wetlands for crop production. The regimes were Water table fluctuation (WTF) Class I-acute slopes segment varying from 0 to 30%, WTF Class II-acute slopes segment varying from 30 to 45% and WTF Class III-acute slope segment > 45%. It is concluded that a controlled water table offers a distinguishing criterion for the development of Inland Valley Bottoms for year round crop production in Ghana.

Journal of Water and Climate Change

This study examined the temperature variations in West Africa's Volta River Basin (VRB) from ... more This study examined the temperature variations in West Africa's Volta River Basin (VRB) from 2021 to 2050 in comparison to the historical period (1985–2014) under two Shared Socioeconomic Pathway Scenarios (SSP2-4.5 and SSP5-8.5). Datasets from three Global Climate Models (GCMs) of the sixth Coupled Model Intercomparison Project (CMIP6) were used. The GCMs and their ensemble were evaluated on a monthly scale. The study used the ensemble mean to analyse the changes in annual and monthly temperature over the Sahel, Savannah, Guinea Coast, and the entire Volta basin. The results demonstrate the individual GCMs reproduced the observed temperature pattern at the VRB, though with some overestimations, but the ensemble mean indicated a better representation of the observed temperature. A warming trend in the basin is projected under both climate scenarios, with higher temperatures projected under SSP5-8.5 compared to SSP2-4.5 in all three zones. The mean annual temperature is projected...

Advances in Agriculture

The growing human population is a driver for higher food demands with a need to scale agricultura... more The growing human population is a driver for higher food demands with a need to scale agricultural production and maintain security of the food supply chain. Thus, there is a need to increase the adoption and improvement of mechanized systems in agriculture, especially where needed labor is also drifting into nonagricultural production sectors. With this view, the relationship or link between population and employment in nonagricultural sector in Ghana (West Africa) to agricultural mechanization was tested to ascertain any such validity. This formed the primary basis for this study and furthered on to establish the current level of agricultural mechanization within the country through measuring effect of available farm energy sources on farm sizes under cultivation. The methods employed included a structured questionnaire administered to farmers and other agricultural stakeholders to determine the level of mechanization, readiness to adopt/accept mechanization technology, level of u...

Journal of Forestry Research

Forest fires are key ecosystem modifiers affecting the biological, chemical, and physical attribu... more Forest fires are key ecosystem modifiers affecting the biological, chemical, and physical attributes of forest soils. The extent of soil disturbance by fire is largely dependent on fire intensity, duration and recurrence, fuel load, and soil characteristics. The impact on soil properties is intricate, yielding different results based on these factors. This paper reviews research investigating the effects of wildfire and prescribed fire on the biological and physico-chemical attributes of forest soils and provides a summary of current knowledge associated with the benefits and disadvantages of such fires. Low-intensity fires with ash deposition on soil surfaces cause changes in soil chemistry, including increase in available nutrients and pH. High intensity fires are noted for the complete combustion of organic matter and result in severe negative impacts on forest soils. High intensity fires result in nutrient volatilization, the break down in soil aggregate stability, an increase s...

American Scientific Research Journal for Engineering, Technology, and Sciences, 2015

The study examined the characteristics of the Sumanpa stream’s Flow-Duration-Frequency Curve stat... more The study examined the characteristics of the Sumanpa stream’s Flow-Duration-Frequency Curve statistics for a period of 25years (1985-2009) and compared the 1990-1999 and 2000-2009 Flow-Duration-Curves. The high, low and mean Flow-Duration-Curves were also analysed. The discharge records were analysed to develop a general quantitative characterization of the stream’s flow variability. Streamflow data was generated from daily stage data using the rating curve model developed at the stream’s gauge station. Flow-Duration-Frequency-Curves were developed using the Weibull plotting position and used to analyse the catchment’s surface and groundwater storage and stream’s flow characteristics. The approach placed the midpoints of the moist, mid-range, and dry zones of the curves at 25 th , 50 th , and 75 th percentiles, respectively. The high zone was centered at the 5 th percentile, while the low zone was centered at the 95 th percentile. For 95% of the time, the streamflowequalled or exc...

Processing Maize to improve its quality does not only prolong its useful life but also increases ... more Processing Maize to improve its quality does not only prolong its useful life but also increases the net profit farmers make and the goodwill derived from consumers. In this study, the emphasis was placed on field evaluation of a locally manufactured motorized maize thresher in Sunyani West Municipality of Ghana. The main objective of the project is to analyze and evaluate a motorized maize thresher for farmers in Sunyani West Municipality of Ghana. The methods used involved the collection and collation of threshing parameters such as threshing speed, maize moisture content for good threshing as well as taking appropriate measures such as reduction of quantitative (Un-threshed Grains and Scatter) and qualitative (mechanical grain damage) losses, and utilizing theories and mechanisms in threshing to determine various threshing parameters. The evaluation of the thresher involved the varying of the shelling shaft speed from 700 rpm to 900 rpm at different maize moisture contents rangin...

Biofuel as an alternative source of energy promises to be a more sustainable replacement of deple... more Biofuel as an alternative source of energy promises to be a more sustainable replacement of depleting fossil energy supplies and exhibits the potential for energy independence in emerging economies because biomass resources used for producing biofuels, especially lignocellulosic wastes are much easily obtained and processed for energy than other technologies available in developing countries . Despite the limitations of many current biofuel production technologies, in terms of resource potential, greenhouse gas emission reduction, ease of application and economic viability, there is considerable interest in biomass gasification. Over the years lots of gasification technologies and models have been developed worldwide. This study examines gasification technologies and mathematical models that have been presented by different authors for the last 35 years with emphasis on the situation in Ghana. The study found out that small scale, air-breathing, direct heating and fixed bed gasifica...

Ghana has so far consumed about 60% (1580 MW) of its hydropower potential with the remaining unta... more Ghana has so far consumed about 60% (1580 MW) of its hydropower potential with the remaining untapped potential being just 820 MW. The country currently lacks adequate financial sources for harnessing renewable energy resources to generate electricity at the levels generated by developed countries. Thermal power which happens to be the best option to the country for firm power generation is relatively expensive. Nuclear power generation has not yet been implemented in Ghana primarily because of its safety requirements and the level of technical knowledge and commitment it requires. It is therefore incumbent on the country to carefully draw and strictly execute coherent energy policies to ensure the supply of affordable, reliable and sustainable power. This research reviews policy formulations, reforms and programmes of Ghana’s power sector from 1966 to 2019 with the aim of having a fair idea of the power landscape and proposing measures and workable solutions for a better understand...

Advances in Research, 2020

Land use conversion significantly impact on sensitive soil quality parameters such as microbial b... more Land use conversion significantly impact on sensitive soil quality parameters such as microbial biomass and soil microbial quotient. Therefore, soil microbial biomass and physicochemical properties were compared under three different land use systems namely agricultural land, degraded mine land and an adjacent natural forest in the Newmont Gold Ghana Limited concessional areas, Kenyasi, Ghana. In our field experimentation, an area of 300 m2 was demarcated in each land use type for soil sampling. In each of the land use type, we collected soil 5 samples at a depth of 0-15 cm in both the dry and wet seasons respectively. Parameters we measured included soil bulk density, pH, particle size distribution, organic carbon, total nitrogen, available phosphorus, microbial biomass carbon and nitrogen, and moisture content. Our results revealed that land use type significantly impacted on soil microbial biomass and physicochemical properties. Microbial biomass carbon and nitrogen was higher in...

Journal of Geography, Environment and Earth Science International, 2020

The development of major social projects such as hydroelectric dams, roads and mining often resul... more The development of major social projects such as hydroelectric dams, roads and mining often result in the loss of properties and sometimes relocation of the affected people or communities. This paper examined the impact of the Bui Dam Hydroelectric project on the livelihood of the people affected, especially farmers in the Bono Region of Ghana. The paper also reviewed the Environmental and Social Impact Assessment (ESIA) report of the project in line with the Environmental Protection Agency requirement, examined the compensation and the living conditions of the farmers in the affected communities. Interviews and focus group discussions of farmers in four communities were conducted which was later followed by the administration of questionnaires to seventy-five (75) farmers. The data obtained from the questionnaires were analyzed using descriptive statistics such as frequencies, percentages and Excel software for the development of charts. The review of the ESIA report of the Bui dam...

Open Journal of Soil Science, 2020

Infiltration is an important component of the hydrological cycle. It provides soil moisture in th... more Infiltration is an important component of the hydrological cycle. It provides soil moisture in the vadose zone to support plant growth. This study was conducted to compare the validity of four infiltration models with measured values from the double ring infiltrometer. The parameters of the four models compared were estimated using the linear regression analysis. The C.C was used to show the performance of the predictability of the models. The RMSE, MAE and MBE were employed to check the anomalies between the predicted and the observed values. The results showed that, average values of the C.C ranged from 0.9294-0.9852. The average values of the RMSE were 4.0033, 17.489, 11.2400 and 49.8448; MAE were 3.1341, 15.9802, 10.6525, and 61.4736; and MBE were 0.0786, 9.5755, −0.0007 and 47.0204 for Philip, Horton, Green Ampt and Kostiakov respectively for the wetland soils. Statistical results also from the Fisher's multiple comparison test show that the mean infiltration rate estimated from the Green Ampt's, Philip's and Horton's model was not significantly different (p > 0.05) from the observed. The results indicated that the Kostiakov's model had the highest deviations as it overestimated the measured data in all the plots. Comparison of the statistical parameters C.C, RMSE, MAE, and MBE for the four models indicates that the Philip's model agreed well with the measured data and therefore, performed better than the Green Ampt's, Horton's and Kostiakov's models respectively in that order for Besease wetland soils. Estimation of infiltration rate by the Philip's model is important in the design of irrigation schemes and scheduling. Therefore, in the absence of measured infiltration data, the Philip's model could be used to produce infiltration information for inland valley bottom

Renewable and Sustainable Energy Reviews, 2018

Abstract Many cookstove designs and biochar programs have been implemented in many countries arou... more Abstract Many cookstove designs and biochar programs have been implemented in many countries around the world. These programs have had varied degrees of success which is generally low. Some were able to achieve all their target objectives, others achieved a fraction of their target objectives whiles others achieved different results from their initial targets. The low success rates have been attributed to disregard for various users’ considerations by the past implementers of such designs and programs. This study seeks to determine the factors and features that Ghana cookstove users want to be incorporated in the designs of their cookstove and biochar programs. The study used a nationwide survey of household cooks. It was found that about 99% of the respondents will prefer a smokeless cook stove. The challenges that they will want eliminated from the conventional cooking systems are ranked from the highest to the lowest as: smoke and heat (35.80%), difficulty in use (21.8%), cost of cooking systems (6.8%), faulty parts (3.1%), and fuel availability (2.90%). About 83% of the respondents have no idea of the use of charcoal as a soil amendment tool (biochar), which presents an opportunity to educate the communities about the potential of biochar to improve soil fertility and quality. This paper therefore recommends that future cookstove designers, researchers and biochar programs implementers consider elimination of smoke and heat as well as fuel availability ahead of the other factors considered in the design of cookstoves.

International journal of water resources and environmental engineering, 2016

A Thesis submitted to the Department of Agricultural Engineering, Kwame Nkrumah University of Sci... more A Thesis submitted to the Department of Agricultural Engineering, Kwame Nkrumah University of Science and Technology, Kumasi in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY IN SOIL AND WATER ENGINEERING College of Engineering. August,2012

Applied and Environmental Soil Science

The field study was carried out on a sandy clay loam forest ochrosol at Hodzo, near Ho in Ghana, ... more The field study was carried out on a sandy clay loam forest ochrosol at Hodzo, near Ho in Ghana, from July 2017 to May 2018. The objective was to determine how tillage and weed control techniques affect the physical properties of the soil. The split-plot design was used in the study, with tillage serving as the main factor and weed control serving as the subplot factor. The tillage treatments were no tillage (NT), minimum tillage (MT), and ploughing followed by harrowing and ridging (PHR) and deep tillage followed by Ploughing, harrowing, and ridging (DPHR). On the other hand, the weed control treatments comprised hoe weeding, machete weeding, and no weeding. It was realised during the study that, in the upper layer (0–15 cm), the PHR treatment produced lower soil penetration resistance (38.57 kPa), high dry bulk density (1.019 Mgm−3), and slightly lower soil moisture content (5.0%) in comparison with the other tillage treatments at three months after planting (3 MAP). The results o...