Well-researched studies were conducted over the entire flood-prone areas, valleys, natural watercourses, swamps, and rivers in Delta State of Nigeria, including existing drains in Asaba, Warri, Effurun, and environs. Several observations were made. Eight of these observations were discussed in my last post. This post is a sequel to the former and a continuation of the observations from these studies:
ix.) The geographical location of Asaba makes it possible to receive all the floodwater generated in Okpanam, since Okpanam town is situated at about 175m above Asaba. This difference in height created the heavy flooding that gathers at the centre of Asaba;
x.) Tidal waves from Warri River create temporary stoppage of discharge of floodwater from the environment, as its occurrence is independent of rainfall;
xi.) Most of the property developers make their foundations very low to the ground, which now makes the roads and drains created in these low-lying terrains, become elevated above the environment, and make intercept of flow discharges difficult from the streets’ drains. These drains provided, only address the removal of floodwater generated on the roads as they now act as embankments, leading to increased flooding in the environments;
xii.) All the marshy swamps and lakes have been occupied with property developments having no regard for the natural watercourses. This is more noticeable in Effurun GRA, Warri GRA, Okumagba/Ugborikoko Marshy Lakes and Edjeba;
xiii.) Some of the drainage channels and culverts on the streets are under-sized, while some culverts across some of the waterways lie above the channel beds, making it difficult to speedily evacuate the floodwater. This is noticeable across Jakpa Road, Uti Road, Olumu Street/Okumagba Avenue;
xiv.) Some streets completely lack the drainage system to evacuate the floodwater generated in their environment. This is more noticeable in Baptist Mission Layout in Warri, Enerhen and;
xv.) Most constructed drains along the major roads are with concrete slabs over them, making it difficult for desilting and other maintenance works since their sections are small to allow human entrance.