Irrigation development and management in Ghana: Prospects and challenges

Agriculture plays a vital role in the national economy but it is predominantly dependent on natural rainfall. Irrigated agriculture on a fairly limited scale is a recent phenomenon and was necessitated largely by the seasonality and unreliability of natural rainfall. The development and management of irrigation, however, has been characterised by difficulties notably weak database, excessive cost, environmental problems and extreme pessimism in some quarters since rainfed agriculture is seen as potentially able to support the present population. Irrigation capacity utilisation on existing schemes is very low and reasons for this situation are put forward, as well as the broad policy objectives needed to promote irrigation development and management. Water management is seen as a serious drawback on existing schemes. It is envisaged that irrigation will be seen in its right perspective as a multidisciplinary activity to ensure the success of schemes. There is the need for running a postgraduate programme in irrigation at the KNUST to enhance the nations efforts at developing and managing irrigation projects successfully

Bridging the Gap between Rural Water Supply and Demand using Harvestable Rainwater: A Case Study of Adansi-Fumso

Rainwater harvesting has several benefits including providing a valuable alternative source of water for households, reduction in flood flow to storm drains and settlement erosion as well as health benefits. The research aimed at assessing and confirming the available renewal water sources, determining the cost of developing a rainwater harvesting system and assessing the potential of rainwater as a supplement to water supply at Fumso. Using a systematic random sampling technique and a sample size of 100 respondents, it was discovered that rainwater harvesting in Adansi Fumso has the potential to conserve on-site potable water use, protect water quality and reduce the risk of flooding within the community. Rainwater was preferred by the community due to its easy accessibility, nature (clean, pure, healthier and tastier), cost and quality. An examination of the rainfall records at AngloGold Ashanti weather station at Obuasi revealed an average annual rainfall of 1449.2 mm with the drier months (November, December, January and February) receiving only a quarter of the average monthly rainfall. The relatively high rainfall means that rainwater harvesting system designs need to be taken as a priority in addressing the water shortage situation in the community. Geometrically uniform building shapes and the local hydrology can provide sufficient rainwater to serve buildings in the community. The cost of the proposed rainwater harvesting system is GH ¢ 389.00 ($256.00). Reasons have been given for the need for this project and recommendations made for its implementation at Adansi Fumso as the best alternative source of water to the fewer boreholes in the community

Environmentally-suspended sediment production of the Nasia River Basin, Northern Ghana

Rivers constitute an important source of surface water supply for most sectors in the world. In areas with single rainfall maximum, as in the north of Ghana, the rivers are normally intermittent or ephemeral with only few perennial ones. The Nasia River Basin is the drainage basin of the left bank tributary of the White Volta within the Guinea Savannah Ecological Zone and lies in the Northern Region of Ghana. The study assessed the level of suspended sediment produced in the Nasia River Basin. Hydrological and meteorological data and water samples were used for the study. Average suspended sediment yield (33 years) in the basin was 19.90 t/km2/yr. With mean annual runoff of 439.13m3/s, 322.43 t/yr suspended sediment is discharged into the White Volta from the Nasia River. Mean suspended sediment concentration and turbidity values for three months of continuous study were 423.86 mg/l and 406.19 NTU respectively. The mean discharged suspended sediment of 0.13 kg/s, 0.25 kg/s and 1.31 kg/s were recorded for April, May and June 2007 respectively for the basin. These levels of suspended sediment deposited in the river bed reduce the carrying capacity of this water system. The study realised that catchment characteristics have a great influence on suspended sediment production in the Nasia River Basin. The reduction of the level of erosion and suspended sediment transport and deposition in the river bed is therefore very important.KEY DESCRIPTORS: River Basin, Drainage System, Guinea Savannah, Suspended Sediment, Turbidity

The impacts of sodicity on soil strength

The paper describes an investigation into the relationship between the level of sodium induced at the soil surface by the evaporation of saline water and the shear strength, both immediately after salinisation and then again after leaching. The results indicate that the strength of the surface increases during salinisation in response to increasing sodicity. The increase in shear strength on leaching became apparent once the levels of sodicity had begun to exceed values currently used to identify when swelling and dispersion are likely to exert an influence on the soil structure. It was also discovered that these effects were not merely confined to the surface but existed throughout the depth of the soil

Domestic water wells in peri-urban areas of Kumasi

No Abstract.Journal of the Ghana Institution of Engineers Vol. 3 (1) 2005: pp. 35-4

Degradation of the Nasia River Basin in Northern Ghana

No Abstract

SIMULATING RICE YIELDS UNDER CLIMATE CHANGE SCENARIOS USING THE CERES-RICE MODEL

The effects of climate change on rice production and yield cannot be overlooked in finding measures to increase production and yield. The CERES-Rice (Ver. 4.O) model was calibrated and evaluated for use in simulating rice yields under different climate change scenarios in Ghana using data from the Anum Valley Irrigation Project. Eighteen years of weather data (1989-2OO6) was used to run the model. The model was found to be sensitive to climatic parameters (temperature, CO2 concentration, solar radiation and rainfall) and had various effects on rice. Simulated rice yields were sensitive to weather years as there was 13% less yield of rice in 1999 compared with 2OO1. Increases or decreases of temperature by 4 °C from the maximum or minimum, decreased rice yields by 34% as compared to base scenario of 2OO6. Similar change in temperatures along with an increase in solar radiation by 1 MJ m-2 day-1, decreased rice yield by 32% compared to base scenario. On the other hand, the same changes in temperature from the maximum and minimum, together with an increase in CO2 concentration by 2O ppm from the standard CO2 concentration of 33O ppm, led to a reduction in rice yield of 33%. Simulations demonstrate that the effects of planting dates cannot be overlooked in finding measures to increase rice yield under climate change mitigations. The effects of climate change on rice yield of will depend on the actual patterns of change in rice growing areas. However, the negative impacts can be averted through appropriate measures such as changes in agronomic practices, development of more temperature tolerant rice varieties and effective training of farmers.Les effets du changement climatique sur la production et le rendement du riz ne peuvent être négligés lors de la prise des mesures pour accroître la production et le rendement. Le modèle Ceres-Rice (ver. 4.O) était calibré et évalué pour la simulation des rendements du riz sous différents scenarios de changement climatique au Ghana en utilisant des données fournies par le projet d’irrigation de la vallée d’Anum. Les données climatiques couvrant 18 ans (1989-2OO6) étaient utilisées dans ce modèle. Le modèle était trouvé sensible aux paramètres climatiques (température, concentration en CO2, radiation solaire et pluviométrie) et présentait des effets variés sur le riz. Les rendements simulés de riz étaient sensible aux années climatiques étant donné 13% de diminution du rendement du en 1999 en comparaison avec 2OO1. Des augmentations ou diminutions de la température de 4 oC du maximum ou minimum, avaient induit une diminution de 34% de rendements comparée au scenario de base en 2OO6. Des changements similaires de température avec un accroissement de la radiation solaire de 1 MJ m-2 jour-1, avait induit une diminution du rendement du riz de 32% en comparaison avec le scenario de base. D’autre part, les mêmes changements en température du maximum au minimum avec une augmentation de la concentration de CO2 de 2O ppm de la concentration standard de CO2 de 33O ppm, avait entrainé une réduction de rendement du riz de 33%. Les simulations démontrent que les effets des dates de plantation ne peuvent pas être négligés dans la recherche des mesures pour accroitre le rendement du riz dans la mitigation des effets de changement climatique. Les effets du changement climatique sur le rendement du riz dépendront des approches actuelles de changement dans les milieux d’exploitation rizicole. Par ailleurs, les impacts négatifs peuvent être évités par des mesures appropriées,notamment les changements des pratiques agronomiques, le développement des variétés de riz plus tolérantes à la température et une formation effective des fermiers

Intercropping and its implications for soil management

Preface Management of the soil encompasses a wide range of practices with the express purpose of improving the capability of the soil to perform the various functions. Improvement in soil management practices will result in increased soil functionality and will be realized only if these practices are based on scientific principles. In assembling this book, we had two primary goals. The first goal was to gather the information about the emerging challenges in soil management from a number of different perspectives. The second goal was to develop this book to help a wide range of readers understand the need and opportunities in improving soil management. As editors and active researchers in the area of soil management, we are aware of the need to enhance our soil and protect our environment for future generations. We feel that we must continue to enhance our soils and prevent further degradation of the soil resource. If we consider the need to increase the world’s food supply over the next 40 yr to meet the demands of the rapidly expanding population, we will have to develop soil management practices capable of increasing and sustaining the production necessary to meet these demands. A focus on the efficiency of the current production systems will be necessary to maximize what we produce from a given amount of water, nutrients, carbon, and light. Our personal concern is that we have not focused enough on how to improve our soils and soil management practices. The demands to produce food, feed, fuel, fiber from our soil resources demands soil with the capability of supplying water, nutrients, oxygen, and microbial diversity. We express our sincere thanks to all of the chapter authors and their unselfish efforts to share their knowledge by preparing these chapters as a summary of the current state of knowledge. Without their dedication to advancing scientific knowledge, it would be impossible to develop this collection of materials covering the diverse set of topics within this book. We also thank the ASA and SSSA headquarters staff for their help and assistance in preparing this final product and the Societies for supporting and encouraging us to undertake this task. Finally, we thank you as the reader for taking the time to increase your knowledge of the challenges in soil management. Jerry L. Hatfield. Thomas J. Saue

Assessment of changing trends of daily precipitation and temperature extremes in Bamako and Ségou in Mali from 1961- 2014

In Mali the annual rainfall is highly variable, ranging from less than 200 mmâ1 300 mm and its distribution is unevenly spread between north and south. Climate change threatens to increase air temperatures and evapotranspiration, increase the risk of intense rainstorms, and increase the risk of heat waves associated with drought. The objective of this study is to assess the change trends of daily temperature and precipitation extremes in Bamako and Ségou in Mali during the period between 1961 and - 2014. Analyses of the changes in trends of daily temperature and precipitation extremes in two regions were studied by calculated extreme climate extreme indices series in RClimdex software. Trends in extreme indices were studied for 5 temperature and 4 precipitation series. Results showed a positive significant decrease of warming trends in cool days, cool nights, whereas warm extreme nights, day times and warm spells on the contrary showed positive significant increasing warming throughout the Ségou region. In Bamako, temperature extreme showed an insignificant trend for negative extremes decreasing warming trends for cold nights and cold days while warm nights, warm days and warm spells showed insignificant positive trends over the period from 1961 to 2014. The results of precipitation extremes for Ségou showed positive significant decrease in consecutive wet day and in extremely wet, whereas Maximum 5 day's precipitation showed positive insignificant increase and the total annual precipitation showed a positive insignificant decrease. In Bamako consecutive wet day, Maximum 5 day's precipitation and total annual precipitation showed positive insignificant decrease. Despite the small number of homogenous temperature and rainfall indices series, the study could present a proportion of significant extremes in Ségou station averages trends. The study provided evidence that during the last 53 years; Ségou was particularly affected by warm extremes based on night time indices rather than cold extremes based on day time indices. Keywords: Climate change and variability, Climate extreme, Climate indices, Rainfall, Temperature, Bamako, Ségo

Microsoft Word - jeas_0913_951.doc

ABSTRACT The Sumampa stream is located in the Municipal capital of Mampong-Ashanti in the forest-savannah agroecological zone of the Ashanti Region in Ghana. The study investigated the changes in the flashiness of the Sumampa stream as a result of increasing human activities in the catchment by assessing the stream's pathlength and RichardsBaker's new flashiness Index (R-B Index), annual and decadal variation in the flashiness Index using daily flow data from 1985 to 2009. The daily flow data was generated from the stream's daily stage data using the stream's rating curve developed by the Department of Hydrology, Kumasi, Ghana. The landuse change scenarios and the rainfall trend coupled with 43.8% of catchment land on 5-10 o slope represent a potentially high erosion risk and an important factor to influence flashiness in a fast expanding urban catchment