The impact of climate change and land use/land cover change on water availability in the Nasia catchment, Northern Ghana.

Water remains the basic necessity for human survival on earth. The study examined the impact of climate change and land use/land cover change on water availability in the Nasia catchment. It employed a concurrent embedded mixed method design of quantitative and qualitative methods, using both primary and secondary sources of data. One-hundred and forty-seven (147) household heads and three (3) key informants were sampled from the study communities in the West Mamprusi, Karaga and Savelugu Municipalities\Districts (Nasia river catchment) using simple random and purposive sampling techniques respectively. Questionnaires, interview guide and focus group discussion guide were used to obtain the primary quantitative and qualitative data from the sampled household heads, key informants and community heads. Quantitative data was analysed based on descriptive statistics including percentages with the help of IBM Statistical Package for the Social Sciences (SPSS) (Version 23) while qualitative data was analysed using thematic analytical framework. The secondary data (temperature, rainfall and discharge time series data) were analysed using MAKESENS Solver from Python software, while Landsat satellite images were processed and analysed using QGIS. Again, time-series data points from secondary sources were used to perform multiple linear regression analyses. Frequency distribution tables, bar charts, graphs as well as verbatim quotations were used to present the analyses. The study found that annual temperatures indicate increasing trends over the past four decades, with minimum temperature increasing relatively faster than the rest. Mean and minimum temperatures in the last two decades have increased by about 1.50C while maximum temperature has increased by about 1.00C. River discharge is declining in the catchment leading to water deficit in some areas over the years. The decline in river discharge in the Nasia catchment corresponds to increasing trends in temperature and variability in rainfall of which all were statistically significant. The Nasia catchment is experiencing changing LULC. Between 1980 and 2020, there was remarkable increase in the extent of built-up/bare land, while farmland, vegetation and water bodies drastically reduced in same period. The study found that rainfall variability makes the river unavailable for domestic applications. The respondents indicated that the water smells, has odor and contains particles. Unfortunately, the study communities have no option but to depend on the river in that state due to the low water table (poor aquifer) in the area. Households at the inlet and outlet of the catchment employ distinct coping strategies to address water-related challenges. In West Mamprusi and Savelugu (outlet), respondents use rain harvesting, alum addition, and water filtering whereas in addition to these strategies, respondents in Karaga (inlet), had to reduce and reuse water. The study recommends that the Department of Water and Sanitation especially in Karaga District should provide the study communities with adequate storage facilities such as poly tanks to store excess rainwater during rainy seasons. This will be somewhat sufficient to supplement the short fall especially in the dry months.

Source: KNUST