Due to chaotic nature of flow in natural open channels and the physical processes and the unknown in a river basin variable, the parameters to be used in studying the behavior of river basin to a given rainfall data cannot be measured directly for this reason, a hydrological model was calibrated and applied to simulate the hydrology of Kaduna River (7112 sq miles) North West Nigeria. Prior to the model calibration, a sensitivity analysis of the hydrognomon model to the parameters was carried out to gain a better understanding of the correspondence between the data and the physical processes being modeled.

This paper applied the use of a stochastic weather generator at the site of a hydrological model to simulate the impact of climate change on the sub-surface hydrological response of Kaduna River as a basis for a sustainable ground water development plan. Average time series of rainfall, temperature and gauge height observed readings were downscaled to the watershed flow volume and applied as forcing to simulate the ground water response as spatially lumped, ignoring the heterogeneous nature of the ground water aquifer. Future simulations indicate increase in base flow, ground storage and decrease soil storage throughout the summer and autumn months for the catchment.

Water distribution systems are designed to adequately satisfy the water requirement for domestic, commercial industrial and firefighting purpose. A spatial database of the water distribution systems (WDS) for Hayin-Banki was created in a Geographic Information System (GIS) environment (ArcGIS), drawing inputs data from water supply and demand. Environmental Protection Agency Network (EPANET, 2.0) was used to analyze the WDS to explore its reliability in current and future scenarios. Mapping of the existing 12.270 km long distribution network revealed that the total length of ductile iron pipe (DIP) is 11.12 km and asbestos cement (AC) pipes is 1.15 km. Running the analysis identified supply gaps, which includes deficiencies in the distribution system (small diameters pipes, system losses) resulting to negative and very small pressures. Running simulations with EPANET and geospatial techniques was used to solve the identified deficiencies.

Urban flooding has become a monumental yearly disaster in many of the world’s cities and Gombe town in particular. This paper focused on some hydro-geomorphological characteristics that influence flooding in Gombe town. Statistical methods and geographic information techniques were used for the assessment. The result revealed that the highest API of 166.62 mm occurred on the 5/9/2014. The rainfall amount was 92.5mm for a duration 48 minutes, average rainfall intensity was 115.63, stage height (1.42m), average flow velocity (0.98m/s), and instantaneous discharge of 9.47m3 /s. This corresponds with the flood disaster that occurred in Gombe town on the same date (5/9/2014). On the other hand, the least API of 18.12 mm occurred on the 18/6/2014. The rainfall amount was 1.2mm for 62 minutes, average rainfall intensity was 1.16, stage height (0.30m), average flow velocity (0.24m/s), and instantaneous discharge of 0.49m3 /s. findings also showed that very steep slope covered 2.4537km2 (1.78%), steep slope covered 3.60235km2 (2.61%), moderate slope (0.735574km2 or 0.53%), gentle slope (131.106km2 or 94.89%) and flat areas (0.259854km2 or 0.19%). The study recommended flood resilience technology, provision of adequate urban drainages and proper storm water management.Keywords: Drainage density, flow accumulation, rainfall, urban flooding