Hart Lawrence^1,, Victor Glory Ukwoma²

The traditional way of handling storm water runoff from cities has always been to drain it as fast as possible by means of drainages. Thus, in urban areas the natural water cycle is been influenced by infrastructures that hinders infiltration and concentrates storm water flows. This approach has been shown to cause several environmental problems as storm water from urban areas can be polluted by heavy metals, organic materials, suspended materials and nutrients when discharged to the nearest receiving river. The main thrust of this work is to modelled basic environmental and spatial parameters for the design of storm water canal that will serve as a means of collecting and conveying the urban runoff of the Greater Port Harcourt City. Consequently, the methodology deployed was terrestrial surveying techniques, bathymetric mapping and hydrological models in other to identify the optimal route for the canal, determination of the topography/configuration of the area, generation of the mathematical parameters of the proposed storm water design location in relation to the adjourning communities and to ascertain the proximal impact of the canal on the neighbourhood. The identified route for the canal covered a total distance of 6.47kms with 100m right of way/corridors in addition to a total of 14 transect lines at 700m on both side of the proposed route with no feasible development outside farmlands. Similarly, the receptacle river, covered a total distance of 750m while the width of river varies from 7.21m to 11.34m. The profile of the identified route presents a continuous gradual decrease in elevation data of 21.94m at SC 19 to 1.89m at SC 5 so also the 700m transects with elevation data decreasing gradually from 16.96m to 2.07m at the centre of the proposed canal. The average time of concentration, rainfall intensity and peak discharge for the various basins along the route were 10.719mins, 49.824mm/hrs and 0.826m³/s respectively, while for the GPH Phase area, the average time of concentration, rainfall intensity and peak discharge were 72.728mins., 13.001mm/hrs., and 1.824m³/s respectively. These are the basic and essential data required for the design of the storm water canal.

storm water, elevation, modelling, Urban, hydrological models, spatial