This study used the double cumulative curve and visual image interpretation methods for the selection of spatiotemporal Landsat data to evaluate the land degradation by anthropogenic activities in the Pra River Basin (PRB) of Ghana. Unsupervised and supervised classification procedures were used to map the land use and land cover (LULC) distribution from 1986 to 2016. Assessment of LULC showed that the PRB has been subjected to six different rates of land degradation in the years 1986, 2000, 2004, 2008, 2013, and 2016. This is due to increase in settlement, cropland, and mining activities to about 130%, 198%, and 304%, respectively. The Markov chain and cellular automation integrated model was successful in predicting LULC distribution in 2016 and the outcomes were comparable to the actual LULC for 2016. The projected LULC for 2025 showed that land degradation is significant in the western and the eastern parts where cropland and forest are, respectively, converted to mining activity. The northern, southern, and middle parts of PRB are expected to experience high settlement expansion, sedimentation in the rivers, and cropland expansion, respectively. The results will aid natural resources management, planning, and sustainable development at PRB. In addition, the research method serves as guideline for other related studies in an attempt to investigate, quantify, and project LULC change in forest ecological areas.

Land use and land cover (LULC) have been and still changing, through human activities, creating variability in hydrological cycle. This paper investigates the hydrological impacts of LULC changes on water balance in the White Volta Basin located in the West of Africa using the Soil and Water Assessment Tool (SWAT). Two LULC data for 1990 and 2006 and two plausible scenarios of land use change were evaluated. Results show a link between land cover and the hydrologic response with a decrease in land cover corresponding to decrease in surface water and base flow and increase evapotranspiration (ET). The results indicated that different LULC contributed to various effects in annual water yield and ET. The results also indicate the capability of the SWAT model to be used in the West African subregion even though there are data limitations associated with the model in West Africa. Overall, the model results support the existing efforts of Volta Basin water resource managers to protect the area along the Volta river against farming and indicate that additional emphasis should be placed on improving land management practices. Water and Environment Journal. Print ISSN 1747-6585 Land cover changes and water balance components A. Awotwi et al. 6 Water and Environment Journal (2014) © 2014 CIWEM. Land cover changes and water balance components A. Awotwi et al. A. Awotwi et al. Land cover changes and water balance components 7 Water and Environment Journal (2014) © 2014 CIWEM. A. Awotwi et al. Land cover changes and water balance components

The Lower Pra River Basin (LPRB), located in the forest zone of southern Ghana has experienced changes due to variability in precipitation and diverse anthropogenic activities. Therefore, to maintain the functions of the ecosystem for water resources management, planning and sustainable development, it is important to differentiate the impacts of precipitation variability and anthropogenic activities on stream flow changes. We investigated the variability in runoff and quantified the contributions of precipitation and anthropogenic activities on runoff at the LPRB. Analysis of the precipitation–runoff for the period 1970–2010 revealed breakpoints in 1986, 2000, 2004 and 2010 in the LPRB. The periods influenced by anthropogenic activities were categorized into three periods 1987–2000, 2001–2004 and 2005–2010, revealing a decrease in runoff during 1987–2000 and an increase in runoff during 2001–2004 and 2005–2010. Assessment of monthly, seasonal and annual runoff depicted a significant increasing trend in the runoff time series during the dry season. Generally, runoff increased at a rate of 9.98 × 107m3yr−1, with precipitation variability and human activities contributing 17.4% and 82.3% respectively. The dominant small scale alluvial gold mining activity significantly contributes to the net runoff variability in LPRB.

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