An extensive narrative review approach is adopted to present existing information on the consumptive and non-consumptive uses and their related issues, such as floods and droughts, climate and the environment in Ghana. Total annual rainfall in the country ranges between 800 mm/y (south-east coat) and 2,000 mm/y (south-west coast) with a bimodal and mono-modal patterns in the south and north, respectively. Annual total runoff from the 3 river systems (the Volta river system, the South-western river system and the Coastal river system) in Ghana is estimated at 40 billion m³ out of about 53 billion renewable freshwater resources. Groundwater yields ranges from 6 m³/h in the Volta basin sedimentary formations to 180 m³/h in the limestone formations. It is estimated that the total water withdrawal as a percentage of total renewable water resources is about 2%. At an average per capita consumption of water of 50 l/p/d, estimated daily water demand for the 2021 population of 31 million people stands at about 566 million m³/y. Current water supply systems are overstretched and it is further estimated that about US $ 240 million is required per year as capital expenditure in urban and rural water supply. Moreover, climate change is projected to increase the scarcity of water in future. Wastewater generated through domestic and industrial uses including storm water in urban Ghana is estimated at about 760 million m³/y. Ghana's irrigation potential to reduce climate change impact on agriculture is put at between 0.36 and 2.9 million ha, accounting for about 66.4% of the consumptive water withdrawal. Estimated water demand for cattle, sheep and goats in 2010 was put at about 22 million m³/y. Other services obtained from surface water are the provision of fish (the Volta Lake is estimated to contributes to 16% of total catch in Ghana); hydropower generation accounting for about 40% of total power installed capacity (Akosombo = 1,020 MW, Kpong = 160 MW, and Bui = 404 MW); water transportation (notably on the Volta Lake); tourist attractions [are 550 km Ghana's shoreline that has about 90 lagoons, the Volta Lake, the lower Volta (e.g., Sogakope, Ada) and some other inland waters like Lake Bosumtwi] and wetlands (recognized by RAMSAR convention of 1971) In the legal context, water governance issues are handled by various institutions created by Acts of Parliament.

Soil loss is not limited to change from forest or woodland to other land uses/covers. It may occur when there is agricultural land-use/cover modification or conversion. Soil loss may influence loss of carbon from the soil, hence implication on greenhouse gas emission. Changing land use could be considered actually or potentially successful in adapting to climate change, or may be considered maladaptation if it creates environmental degradation. In semi-arid northern Ghana, changing agricultural practices have been identified amongst other climate variability and climate change adaptation measures. Similarly, some of the policies aimed at improving farm household resilience toward climate change impact might necessitate land use change. The heterogeneity of farm household (agents) cannot be ignored when addressing land use/cover change issues, especially when livelihood is dependent on land. This paper therefore presents an approach for simulating soil loss from an agro-ecosystem using multi-agent simulation (MAS). We adapted a universal soil loss equation as a soil loss sub-model in the Vea-LUDAS model (a MAS model). Furthermore, for a 20-year simulation period, we presented the impact of agricultural land-use adaptation strategy (maize cultivation credit i.e., maize credit scenario) on soil loss and compared it with the baseline scenario i.e., business-as-usual. Adoption of maize as influenced by maize cultivation credit significantly influenced agricultural land-use change in the study area. Although there was no significant difference in the soil loss under the tested scenarios, the incorporation of human decision-making in a temporal manner allowed us to view patterns that cannot be seen in single step modeling. The study shows that opening up cropland on soil with a high erosion risk has implications for soil loss. Hence, effective measures should be put in place to prevent the opening up of lands that have high erosion risk.

The forecast of rainfall and temperature is a difficult task due to their variability in time and space and also the inability to access all the parameters influencing rainfall of a region or locality. Their forecast is of relevance to agriculture and watershed management, which significantly contribute to the economy. Rainfall prediction requires mathematical modelling and simulation because of its extremely irregular and complex nature. Autoregressive integrated moving average (ARIMA) model was used to analyse annual rainfall and maximum temperature over Tordzie watershed and the forecast. Autocorrelation function (ACF) and partial autocorrelation function (PACF) were used to identify the models by aid of visual inspection. Stationarity tests were conducted using the augmented Dickey–Fuller (ADF), Mann–Kendall (MK) and Kwiatkowski–Phillips–Schmidt–Shin (KPSS) tests respectively. The chosen models were evaluated and validated using the Akaike information criterion corrected (AICC) and also Schwartz Bayesian criteria (SBC). The diagnostic analysis of the models comprised of the independence, normality, homoscedascity, P–P and Q–Q plots of the residuals respectively. The best ARIMA model for rainfall for Kpetoe and Tordzinu were (3, 0, 3) and (3, 1, 3) with AICC values of 190.07 and 178.23. That of maximum temperature for Kpetoe and Tordzinu were (3, 1, 3) and (3, 1, 3) and the corresponding AICC values of 23.81 and 36.10. The models efficiency was checked using sum of square error (SSE), mean square error (MSE), mean absolute percent error (MAPE) and root mean square error (RMSE) respectively. The results of the various analysis indicated that the models were adequate and can aid future water planning projections.

Purpose: This paper aims to assess the rate and land category contributing to the changes in seven land-uses in the Kintampo North Municipality of Ghana and the effect of the decisions of land users on future landscapes. Design/methodology/approach: LANDSAT images were classified to generate land use/cover maps to detect changes that had occurred between 1986 and 2014. In total, 120 farmers were also interviewed to determine their perceptions on land use changes. Interval, category and transition levels of changes were determined. Savanna woodland, settlement and forest were mostly converted to farmland in both intervals (1986-2001 and 2001-2014). Findings: Results showed that rock outcrop, plantation, cropland and savanna woodland increased at an annual rate of 13.86, 1.57, 0.82 and 0.33 per cent, respectively, whilst forest, settlement and water body decreased at 4.90, 1.84 and 1.17 per cent annual rate of change, respectively. Approximately, 74 per cent of farmers will not change land use in the future, while 84.2 per cent plan to increase farm sizes. Research limitations/implications: The study shows that more land cover will be targeted for conversion as farmers expand their farmlands. There is the need for strict implementation of appropriate land use/cover policies to sustain food production in the region in this era of changing climate and population increase. Originality/value: This research assessed the land use changes in the Kintampo North Municipality and its impacts on agriculture and carbon stocks release via land use changes. It identified how the decisions of the local farmers on land management will affect future landscape.

Soil infiltration at a watershed scale is important for understanding and predicting the hydrological process in soil-water-plant systems. This study investigated the effects of land use (LU) conversion on the infiltration rate in the Ouriyori watershed. To that end, in situ infiltration was carried out over the watershed under thirty-six pairs of adjacent cropland-fallow plots using the hood infiltrometer. Saturated hydraulic conductivity (K_s), soil properties, and soil classes were further compared. Results showed a high variability of K_s following the LU classes with a coefficient of variation greater than 60. After data log transformation, the mean values of K_s showed high infiltration and ranged between 2.59 and 2.42cmd⁻¹, respectively, for fallow land and cropland. Thus, K_s was relatively lower in cropland compared to fallow land. Hence, the low infiltration recorded in croplands indicated the degradative impacts of unceasing tillage operations for crop production without crop residue incorporation into the soil during tillage. There was no significant difference in bulk density and soil texture in both types of land use. Considering soil classes, the highest infiltration rate was found in Ferric Luvisol and the lowest rate in Dystric Gleysol, meaning that the high infiltration observed in Ferric Luvisol was due to the abundance of soil macropores. Change in natural vegetation to croplands induced a low infiltration rate and macropore connectivity. Moreover, fallow lands tend to provide water storage capacity through the improvement of mesopores, while soil compaction through agricultural activities reduces soil porosity and therefore soil infiltration. In addition, the paired Students t-test performed on the transformed data was statistically significant, indicating a difference between K_s under cropland and K_s under fallow land. To improve soil and water conservation for crop production as well as for sustainable rural populations livelihoods in the watershed, occasional fallowing may be observed to dampen infiltration hindering soil surface conditions.