Andrew Manu

Application of remote sensing and GIS technologies to assess the impact of surface mining at Tarkwa, Ghana

The industrial and small-scale mining industries have provoke serious environmental degradation in the form of deforestation, soil erosion and soil and water contamination by Hg and other heavy metals. Remote sensing and GIS technologies were used to investigate the temporal and spatial extent of environmental degradation from 1986 to 2000 in the Tarkwa mining area. While most of the study area was a healthy ecosystem in 1986, by 2001, over 60% of the land was degraded to the point where it could not be used for any commercial activity. An additional 35,000 ha of land has been polluted and remediation would be very expensive. This state of environmental degradation through mining activities was further aggravated by extreme human population encroachment of the region. This study puts into perspective the need for the government to institute strict environmental regulations to protect mining areas.

The impact of urban growth and long-term climatic variations on the sustainable development of the City of Niamey, Niger

This study uses remote sensing and Geographic Information Systems (GIS) technologies to examine the combine effects of urban expansion and climatic variability on the physical environment in and around the city of Niamey. The results revealed a notable increase in the built up areas in the city between 1973 and 2001.While the city’s population was increasing, prime agricultural lands were also declining at increasing rate. This was due to human disturbances on the fragile Sahelian ecosystem and climatic variability associated with this area. The consequence was increased erosion, loss of biodiversty and declining water quality. Policy intervention in the form of zoning, moratorium and other growth management strategies was suggested as a way of preventing the city from exceeding its carrying capacity.

Relationships between Climate Parameters and Forest Vegetation At and Near Digya National Park, Ghana

This paper evaluates the effect of three climate parameters on forest cover in Ghana and the normalized difference vegetation index (NDVI) at Digya National Park derived from Landsat image data. Climate data (temperature, humidity, dewpoint, rainfall) are assembled from statistics provided by Ghanas Meteorological Agency. The study introduces a weighted averaging method by computing weather information from neighbouring stations. Also, this research introduces a model of dewpoints, enabling the direct calculation of dewpoints from temperature and humidity data. The major finding is that while temperature significantly affects forest cover and Park vegetation, dew-points and rainfall do not. The paper suggests where future research may be more fruitful in analyzing the effects of climate on vegetation.

Investigation of the impact of urban sprawl in three Sahelian cities using remotely-sensed information

Rapid urban growth and the environmental, social and political consequences are major issues in Africa, especially in the major Sahelian cities. Using remote sensing technologies, it has been established that between 1980-2000, the rate of urbanization more than doubled in the capital city of Burkina Faso (118% increase) and nearly doubled in capitals of Mali (62%) and Niger (63% increase). There has been a drastic conversion of vegetated and open lands to urban and residential use. Population in these cities also grew significantly, clearly outpacing the overall population growth of the countries. Data obtained is useful in policy issues related to sustainable urban planning and also serves as input into urban growth to predict patterns of future urban expansion.

The use of satellite imagery in rangeland management: a comparative analysis of three Sahelian zones

Among the most vulnerable environments in Africa are the rangelands of the Sahel. This study compiles a sequential database designed to clarify how Sahelian rangelands are changing and in response to what factors. Also reviewed are common theories about how rangelands are affected by drought, for example by use of misguided methods of farming. The most important policy recommendation on rangelands is that governments advocate and plan for public participation in solving the problem. In addition, governments should foster monitoring and analysis procedures which are national in scope compatible with global approaches.

Management of watersheds with Landsat TM data: a case study of the Volta River in Ghana

Notwithstanding the huge national achievement of Ghana supplying the main focus of its independence in the early years, the Volta River Project continues to have many negative consequences which impact large parts of the country. Remote sensing methods are introduced to show how information about these impacts may be obtained and used in sensible management programs. The monitoring literature suggests that a surprising range of relevant and remotely sensed information may be provided. In this study, this information is discussed and evaluated for its significance and its potential value for the evolution of Ghanaian policy.

The use of GIS and satellite remote sensing techniques for the management of inland dry valley systems of the Sahel: the case of the watershed toposequence of Tanda, Niger

Environmental degradation is a serious problem in the fragile ecosystem of the Sudano-Sahelian zone of West Africa. To test, adopt and extend appropriate technologies to prevent further degradation, remote sensing and GIS technologies were used to identify, and characterize a farmer-manageable in-land dry valley system in Niger. Appropriate land management units were delineated. Interventions that will address specific natural resource management problems specific to each land management unit but also linked to the restitution of other units were tested. This holistic approach has proven successful and it is being extended to regions of similar ecosystems.