**8. Impacts of land use activities on river hydrology**

Land use changes in the upper catchment areas through the city to the lower areas were observed as the causes of water quality degradation [6, 20]. This is further attributed to increased storm water, reduced infiltration rates and hence flooding in the urban areas.

Poor land use and management impacts on the hydrology of the catchment resulted to surface run-off increases which then determined the increased discharge of the rivers. In the sub-basins investigated and downstream the Athi River Catchment area, physical water quality parameters increased with discharge downstream the river courses while metallic ions decreased or increased depending on river subbasin as shown in **Table 8**.

The study noted a general trend of increase in total suspended sediments with increase in river volume (discharge) and consequently more pronounced water turbidity. The reverse, it may be attributed to river widening in channel size and more settling or deposition of the sediments. In addition, the study noted that away


*A Critical Analysis of the Water Quality Impacts on Water Resources in the Athi River… DOI: http://dx.doi.org/10.5772/intechopen.99667*

*Source: field data (1998–2017); COND-Electric conductivity,TDS-Total dissolved solids,TSS-Total suspended sediments,TUR-Turbidity.*

#### **Table 8.**

*Mean measured values of physical water quality parameters at various sampling points.*

from the main land use activities, water in the streams was found to be less polluted both physically and chemically. This implies much of water quality degradation in the upper catchment areas was attributed to changes in land use activities.
