Yeboah Gyasi-Agyei

Griffith University · School of Engineering and Built Environment

Water scarcity is a major challenge for irrigated agriculture, particularly in developing countries where access to meteorological data for calculating reference evapotranspiration (ETo) is limited. Thus, this study explores the potential of two machine learning models (random forest (RF) and long short-term memory (LSTM)) and autoregressive integr...

Thirteen satellite precipitation products (SPPs), re-gridded to 1 km resolution, were evaluated in terms of the structural similarity index (SSI) over the Pra catchment in Ghana. Three SPP scenarios were considered: Scenario one (S1) was the original SPPs; Scenario two (S2) was bias-corrected SPPs; and Scenario three (S3) was the better of S1 and S...

The design and application of multiple tools to map soil micronutrients is key to efficient land management. While collecting a representative number of soil samples is time consuming and expensive, digital soil mapping could provide maps of soil properties fast and reliably. The objective of this research was to predict the spatial distribution of...

Winemaking in Chile is a long tradition that is recognised around the world. It is especially important in the Maule region where more than 40% of the total wine in the country is produced. However, there is a lack of studies related to soil erosion in vineyards in Chile, especially considering the extreme rainfall events that occur in the country....

The design and application of multiple tools to spatially assess soil properties are key to efficient land management plans. While soil micronutrients are paramount soil properties for multiple purposes, collecting a representative number of samples is time-consuming and expensive. The main aim of this research was to evaluate different scenarios i...

In this article, a comprehensive literature review was conducted to investigate why urban water organisations are still lacking climate change adaptation in their water security management and planning, the key barriers and how they could be solved and enabled. In addition, urban water crises in the last decade have been examined to emphasise what...

Evaluation of grazing impacts on land degradation processes is a difficult task due to the heterogeneity and complex interacting factors involved. In this paper, we designed a new methodology based on a predictive index of grazing susceptibility to land degradation index (GSLDI) built on artificial intelligence to assess land degradation susceptibi...

Accurate prediction of digital soil map allows evaluation of larger areas with respect to the design of efficient land management plans at the regional scale. Nowadays, there is an increasing demand for high spatial resolution gridded soil data for crop planning and management because it saves time and costs. One of the most essential soil physical...

Advancing knowledge on how climate change impacts on water resources is considered a priority in the academic world. This paper studies the strategies adopted by urban water professionals in the tropical region of Queensland, Australia to minimise the impacts of climate change on the regional urban water supply network. In the recent past, the dry...

Assessing irrigation water quality is one of the most critical challenges in improving water resource management strate- gies. The objective of this work was to predict the irrigation water quality index of the Bahr El-Baqr, Egypt, based on non- expensive approaches that requires simple parameters. To achieve this goal, three artificial intelligenc...

Prediction of crop yield is an essential task for maximizing the global food supply, particularly in developing countries. This study investigated lettuce yield (fresh weight) prediction using four machine learning (ML) models, namely, support vector regressor (SVR), extreme gradient boosting (XGB), random forest (RF), and deep neural network (DNN)...

Unsustainable grazing of animals exerts pressure on a range of environmental factors. This review assessed the impacts of grazing of small ruminants (sheep and goats) on hydrological processes (e.g., runoff occurrence, erosion) within European pasture lands. It also considered other effects of small ruminants grazing such as water pollution. Our re...

Evaluation of grazing impact on land degradation processes is a difficult task due to heterogeneity and complex interacting factors involved. In this research, we designed a new methodology based on a predictive index of GSLDI (Grazing Susceptibility to Land Degradation Index) built on artificial intelligence to assess land degradation susceptibili...

Statistical imputation techniques for infilling missing records in daily rainfall data within the Pra and the Densu River basins in Ghana were evaluated. The imputation techniques considered were Mean, Regression, Multiple Imputation by Chain Equation, K Nearest Neighbor, Probabilistic Principal Component Analysis, missForest, Linear Interpolation,...

Background Water pollution with heavy metals is a severe dilemma that concerns the whole world related to its risk to natural ecosystems and human health. The main objective was to evaluate the removal efficiency of Cd of various concentrations from contaminated aqueous solution by use of two cyanobacterial strains ( Nostoc muscorum and Trichormus...

It is essential to investigate the impact of climate change on the water footprint (WF) of rice from both historical simulation and future projections. In this study, four machine learning (ML) models, including random tree (RT), random forest (RF), additive regression (AR) and reduced error pruning tree (REPT) were used to model blue and green wat...

There are limited literature on the impacts of drought on crop yields in warm regions such as southwest China. Drought vulnerability of four different crops (wheat, rice, maize and sugarcane) cultivated in three provinces (Sichuan, Guizhou and Yunnan) within southwest China were investigated in this study. It was based on the drought index of stand...

Background: Water pollution with heavy metals is a severe dilemma that worries the whole world related to its risk to nature ecosystem and human being health. The main objective is to evaluate the removal efficiency of Cd with various concentrations from contaminated aqueous solution by two Cyanobacteria species (Nostoc muscorum and Anabaena variab...

Drought is showing an increasing trend as a result of the significant variation in precipitation and temperature in China. This study investigated the impacts of drought on ecosystem water use efficiency (WUE) in southwest China. The spatiotemporal distribution of drought and ecosystem WUE were analyzed through integrated approaches based on observ...

Railways play a key role in the connection between urban and rural areas and enhance the economic sectors of many countries. However, little is known about wind regimes within the railway corridors, particularly in developing countries. The main aim of this research is to identify and analyze wind regimes and sand drift potential (DP) within the Sa...

Accurate estimation of drought events is vital for the mitigation of their adverse consequences on water resources, agriculture and ecosystems. Machine learning algorithms are promising methods for drought prediction as they require less time, minimal inputs, and are relatively less complex than dynamic or physical models. In this study, a combinat...

There is a lack of information on the extent of mineral extraction by plants from wastewater in arid and semi-arid environments in developing countries. This research assesses the performance of Alhagi and Mallow plant species for the absorption of heavy metals around the tailings dam of a copper mine in Iran. The industrial wastewater, known as th...

The main aim of this research was to determine the potential effects of different tillage systems (TT: traditional tillage and RT: reduced tillage) on runoff and erosion at two different locations (Kahramanmaras and Tarsus, Southern Turkey) under (i) fallow, (ii) wheat (Triticumaestivum L.), and (iii) sainfoin (Onobrychissativa L.) crops. Rainfall...

Traditionally, rainfall-runoff studies are some of the most important methods to help the understanding of the hydrological processes, management of water resources, and potential risks associated with extreme rainfall events (e.g., soil loss, flash-floods, and landslides). This chapter aims to show how an efficient hydrological experimental fieldw...

Assessment of the variation of soil erosion and sediment mobilization at different hillslope positions using the 137Cs tracing technique has been carried out for the Dapotou closed watershed, a representative depression in the karst gabin basin in Southwest China. The results showed that the annual soil erosion rates in the shoulders, backslopes, a...

Predicting the effects of land-use (LU) changes and hydrological processes on a rapidly urbanized catchment using the Markov chain and WetSpa models is the main objective of this research. Hourly hydrometeorological data for 2001-2016, land use maps, a digital elevation model (DEM) and soil texture were used as inputs into the models. The simulatio...

Rain gauges continue to be sources of rainfall data despite progress made in precipitation measurements using radar and satellite technology. There has been some work done on assessing the optimum rain gauge network density required for hydrological modelling, but without consensus. This paper contributes to the identification of the optimum rain g...

To understand soil erosion processes, it is vital to know how the weather types and atmospheric situations, and their distribution throughout the year, affect the soil erosion rates. This will allow for the development of efficient land management practices to mitigate water-induced soil losses. Vineyards are one of the cultivated areas susceptible...

Solarisation technology allows for improving soil quality as well as crop productivity. The influence of the properties and method of use of plastic materials used to cover soils, such as the number and thickness of layers, and colour of the material, significantly alters soil thermal-physical properties. These effects can be managed and modified t...

Spain is one of the largest wine producers in the world, with Extremadura (south-west Spain) being its second-largest producing region after Castilla La Mancha. Within Extremadura, the most traditional and productive viticulture region is the Tierra de Barros, which boasts an annual production of 3×10 6 litres. However, no soil erosion assessment h...

Persimmons (Diospyros kaki) are trees cultivated under subtropical environmental conditions but are also found in other regions such as the Mediterranean. However, no research has been conducted to investigate soil erosion processes under Mediterranean soil management systems characterized by flood irrigation and/or tillage. The Improved Stock Unea...

Solarisation application by mulching the soil with a polyethene plastic film has a significant influence on soil thermal characteristics (TCs), which, in turn, show a strong impact on soil energy balance and agricultural productivity. In countries like Iraq with highly populated cities, such as Baghdad, that need large quantities of agriproducts, t...

Nowadays through the world as well as in Iran, petroleum hydrocarbons have majority contribution in environmental ricks for human and other organisms. Therefore, this study evaluates hydrocarbon pollution effects on soil chemical properties, as well as soil magnetic susceptibility on a petroleum refinery compound in Isfahan province, Iran. It also...

Water is polluted by increasing activities of population and the necessity to provide them with goods and services that use water as a vital resource. The contamination of water due to heavy metals (HMs) is a big concern for humankind; however, global studies related to this topic are scarce. Thus, the current review assesses the content of HMs in...

New trends related to market incomes, cultural human development, non-sustainable soil management practices, and climate change are affecting land abandonment in Mediterranean sloping vineyards. It is generally accepted that hydrological processes and, subsequently, soil erosion rates are usually different between cultivated and abandoned soils. Ho...

In this paper, simple methods for validating the emitter characteristics of driplines and pump performance curves for dripline network design and simulation are presented. Pressure compensating driplines were tested and used to aid grass establishment to control erosion on the steep slopes of a newly constructed flood levee. The dripline networks c...

Conditional daily rainfields were generated using collocated raingauge radar data by a kriging interpolation method, and disaggregated into hourly rainfields using variants of the method of fragments. A geographic information system (GIS)-based distributed rainfall–runoff model was used to convert the hourly rainfields into hydrographs. Using the c...

Advances in soil erosion measuring tools and micro-topography modelling will contribute to our understanding of land degradation processes and help to design correct erosion mitigation measures in agricultural fields. Vineyards being one of the most degraded agricultural landscapes, it is necessary to accurately predict soil erosion levels within t...

Parent material can determine specific physical and chemical soil properties and, therefore, soil erosion rates. However, for new vine plantations, there is not enough research on soil erosion assessment on different parent materials which could be helpful for agricultural management plans. The main aim of this research was to quantify soil erosion...

In vineyards, especially on steep slopes like the Ruwer-Mosel Valley, Germany, soil erosion is a well-known environmental problem. Unfortunately, some enterprises and farmers are not aware of how much soil is being lost and the long-term negative impacts of soil erosion. The non-invasive technique of the stock unearthing method (SUM) can be used fo...

Water metering has traditionally been seen as a means of measuring the amount of water consumed primarily for billing purposes. However, with the recent entry into the market of smart water meters, metering is now increasingly considered as an integral aspect of integrated water management. The purpose of this paper was to undertake a review of urb...

This paper has established a link between the spatial structure of radar rainfall, which more robustly describes the spatial structure, and gauge rainfall for improved daily rainfield simulation conditioned on the limited gauged data for regions with or without radar records. A two-dimensional anisotropic exponential function that has parameters of...

Spatial variability of rainfall has been recognised as an important factor controlling the hydrological response of catchments. However, gauged daily rainfall data are often available at scattered locations over the catchments. This paper looks into how to capitalise on the spatial structure of radar rainfall data for improving kriging interpolatio...

Given a record of daily rainfall over a network of gauges, this paper describes a method of linking the Gauge Wetness Ratio (GWR) on a given day to the joint distribution of the parameters of the anisotropic correlogram defining the spatial statistics of simulated radar-rainfall fields. We generate a large number of Gaussian random fields by sampli...

Railway formation (embankments and cuttings) in Queensland are experiencing increased maintenance costs due to rainfall induced erosion and sedimentation problems. The erosion problems can be reduced by establishing grass cover on the steep slopes (batters). The objective of the research reported in this paper was to develop a continuous rainfall-r...

A well-maintained railway system is an essential requirement in the successful running of heavy haul coal railway networks. To minimise whole of life costs incurred in such a rail network, infrastructure assets must be effectively managed. Incurred costs clearly include the maintenance cost of failures and the resulting delays and cancellations. A...

The use of a Bayesian approach to identify the emitter insertion head loss coefficients required for the design of drip laterals is demonstrated. Total discharge and pressure measurements taken along commercially available 100 m rolls of pressure compensating drip laterals laid on a 1% slope wooden platform were used. The Metropolis-Hastings Markov...

An enhanced copula-based daily rainfall disaggregation model is presented. The rainfall data are grouped into maximum daily temperature quantiles instead of the usual monthly grouping in order to account for seasonal temperature shifts. Empirical and statistical evidence provided supports the conditioning of the model parameters on temperature. Lin...

A distributed 1D rainfall–runoff model is presented. It consists of the Saint Venant continuity and momentum equations for overland flow and a modified Green-Ampt model for the infiltration on railway embankment steep slopes. The model is applied to adjacent 10-m-wide erosion control experimental plots with different percentages of grass cover. A r...

Pair-copula construction methodology has been explored to model the dependence structure between net storm event depth (R), maximum wet periods' depth (M), and the total wet periods' duration (L), noting that the total storm event depth is R T= R+ M. Random variable R was used instead of R T in order to avoid physical boundary effects due to the co...

It has been demonstrated in this paper that observed scaled daily storm profiles (OSDSPs) can be used at a different climatic site to disaggregate daily rainfall data into fine timescales by following some selection rules. For a given daily rainfall depth, the normal copula model predicts the total daily wet periods’ duration, capturing the seasona...

Runoff properties for rehabilitated mines are needed for a number of purposes including sizing mine water holding dams, planning for erosion control and more general mitigation of downstream impacts. This paper reports analyses of rainfall simulator rainfall-runoff-erosion plot scale trials carried out as part of the Post-Mining Landscapes Project....

This paper contributes to the reproduction of the limited fine timescale rainfall time series from the abundant daily rainfall time series. It provides a copula based daily rainfall disaggregation model to predict the total wet period's duration (L) for given daily rainfall amount (R). Transition probabilities, parameterised by L, are used to aid t...

To aid in the simulation of runoff for Lake Michigan diversion accounting, a dense network of 25 rainfall gages has been operated by the Illinois State Water Survey since 1989. About 2000 storm events have been identified from the 21 years of space-time continuous rainfall data recorded at a one hour timescale. The space-time dependence structure o...

Unpredictable rainstorms can pose greater risks of soil erosion on newly formed unprotected railway batters. A bioengineering approach consisting of revegetation can be an effective tool for soil-erosion control. Perennial species, such as buffel grass, are preferred for durability of vegetation cover in the arid and semiarid tropics. However, it t...

Emitters inserted in drip irrigation laterals cause local head loss, generally estimated as a product of a coefficient and the velocity head. This local head loss coefficient and the emitter discharge curve hydraulic parameters may exhibit considerable variability attributable to the manufacturing process. This paper provides a framework for assess...

A daily rainfall disaggregation model, which uses a copula to model the dependence structure between total depth, total duration of wet periods, and the maximum proportional depth of a wet period, is presented. The wet(1)-dry(0) binary sequence is modeled by the nonrandomized Bartlett-Lewis model with diurnal effect incorporated before superimposin...

Buffel grass (Cenchrus ciliaris) is one of the preferred species for revegetation of railway embankment steep slopes (batters) in Central Queensland, Australia. Its seed germination is inherently poor and becomes unpredictable, especially in semi-arid regions characterized by low rainfall, due to its extended period of dormancy. Thus its use for ra...

Embankments and cuttings are integral parts of rail and road networks that support the economy of every country including Australia. Water induced erosion from the steep slopes (batters) of these civil engineered structures costs tax-payers in terms of ongoing operation and maintenance of the land transport networks. Also the environment is degrade...

A robust model for disaggregation of daily rainfall data at a point within a large region to any fine timescale of choice is presented. Limited fine timescale data are required to calibrate only three parameters for the regional model, to establish monthly variation of simulation timescale lag-1 autocorrelations, and also to establish a scaling law...

Grass establishment on railway embankment steep slopes for erosion control in Central Queensland, Australia, is aided by drip lateral irrigation systems. The effective field values of the lateral parameters may be different from the manufacturer supplied ones due to manufacturing variations of the emitters, environmental factors, and water quality....

Erosion damage to railway embankment and cutting steep slopes (batters) causes a significant cost of remediation within the coal railway network of Central Queensland, Australia. It has been established that grass cover of 60% reduces erosion by over 90%. Given that water is a scarce commodity in the semi-arid environment, a more efficient water us...

It is a standard practice to establish grasses on steep slopes (batters) of embankments and cuttings to minimise erosion problems. However, the increase in grass density (high biomass) on the steep slopes poses a greater risk of fire. Controlled burning is a common fuel hazard reduction program employed to minimise the fire risks. The increased ris...

The Australian SILO Data Drill facility generates continuous daily rainfall data from 1889 to current date for any set of coordinates on the Australian continent. For the daily rainfall data to have any appeal to users, such as farmers and environmental modellers, a robust disaggregation model that generates sub-daily time series fully consistent w...

An advanced technology cost-effective drip irrigation system design and setup on environmentally sensitive elevated steep slopes (batters) of a coal train derailment site in Central Queensland, Australia, are presented. The final profile of the coal burial site consists of six batters and associated berms with a drop in elevation of about 35 m. A s...

The focus of this paper is the optimum use of mulch (biodegradable erosion control blankets and waste ballast) on steep slopes (batters) to aid the establishment of grasses for erosion control. Biodegradable blankets are commonly used on steep slopes as mulch to minimize the risk of washout of soil, seeds, and ameliorants during grass establishment...

Existing technologies have been tailored to deliver cost-effective irrigation on a railway embankment and excavated steep slopes (referred to as batters) within a semiarid environment. Irrigation is to aid the establishment of 100% grass cover within a few weeks to mitigate soil erosion problems. It is based on water sourced from a temporary excava...

Research into cost-effective strategies for erosion control (HEFRAIL Project) on railway earthworks steep slopes (batters) in Central Queensland, Australia, has established that 100 % grass cover reduces erosion by over 90 % compared with the bare scenario. The strategies are centred on amelioration of the largely dispersive, sodic, saline and extr...

Water has been identified as a key component to the success of grass establishment on railway embankment batters (side slope) within Central Queensland, Australia, to control erosion. However, the region under study being semi-arid experiences less than 600 mm average annual rainfall occurring on about 60 days of the year. Culverts and bridges are...

Strategies for erosion control on a railway embankment batter (side slope) are quantitatively evaluated in this paper. The strategies were centred on control (‘do nothing’ treatment), grass seeding, gypsum application, jute mat (an erosion control blanket) placement and planting hedgerows of Monto vetiver grass. Rainfall and runoff were monitored a...

A hybrid model for point rainfall has been explored to model the diurnal cycles in rainfall properties. The hybrid model is a product of two random processes: an occurrence process and an intensity process. Two occurrence process models, first-order Markov chain and periodic discrete autoregressive, were compared initially. Fourier series was fitte...

This paper demonstrates how the Gyasi-Agyei–Willgoose hybrid model for point processes could be regionalised for daily rainfall disaggregation using limited high resolution data within a region of interest. Their model is a product of the binary non-randomised Bartlett–Lewis rectangular pulse model and a lognormal autoregressive model used as a jit...

A generalised hybrid model to generate point rainfall for a wide range of aggregation levels is presented in this paper. The rainfall process is expressed as a product of a binary chain model, which preserves the dry and wet sequences as well as the mean, and a correlated jitter used to improve the deficiencies in the second-order properties of the...

A hybrid point rainfall model, a product of two random processes, is presented. The model uses a jitter model, a general technique for improving the fit of any point process based model. We use the nonrandomized Bartlett-Lewis rectangular pulse and an autoregressive model as a jitter. First, the five parameters of the Bartlett-Lewis model are estim...

This paper presents a technique for the determination of a dynamic hillslope instantaneous unit hydrograph (IUH) in concert with a variable saturation excess runoff production model using a grid-based digital elevation model (DEM). The total channel network responsible for routing the runoff produced on the catchment is divided into two parts: the...

The advent of digital elevation models (DEMs) has made it possible to objectively extract, calculate and store geomorphological parameters for hydrological modelling at several scales. For a grid-based DEM, the threshold area used to extract the channel network is analogous to the scale of the map produced. In addition to the map scale, the effects...