the ondjiva paradox | taming the flood 1 2 Taming the Flood Our flooding, flood defense and river engineers’ objectives for Ondjiva were first to activate immediate emergency rehabilitation measures and then develop a flood mitigation strategy that relieves the city and new developments growing around it from the hazards of flooding down to non-threatening level while ensuring that benefits derived from flood water remain the same. The emergency rehabilitation works that were mobilized in 2009 protected from more flooding during that season. But it was evident that the city lacked permanent mitigation measures as well as comprehensive upgrading and development of basic infrastructure networks. These new drainage works are based on the Ondjiva City December 2011 Urban and Infrastructure Master Plan meant to serve as a tool for the implementation of Integrated Urban and Infrastructure Programs over a 25-years horizon. Ironically, these chanas constitute both a source of life providing water for people and livestock, aquifer recharge, and fishing , and a threat flooding farms, roads, houses, and infrastructure of populated areas in the flood plain. Most of the population within the city depends on local agriculture for food and income including small farming We worked to find an applicable solution better suited than channelization to define and delineate the flood plain, tame the River and protect urban areas. We also initiated a number of rehabilitation and upgrading works of existing culverts. In 2009 eight dikes were constructed and 14 culverts were rehabilitated in the City of Ondjiva part of the emergency first response relief strategy we implemented. The floodplains remained dry during the 2010 and 2011 rainy seasons, meanwhile, the long term phased drainage and storm water protection master plan for the city’s two urban areas: the Central Area and the Kachila I District was started. The bulk of the storm water master plan is implemented within these initial phases and includes upgrades and additional channeling. The channels’ gravitational force are designed to carry the flow away from urban areas and upgraded roads and discharge into existing natural water courses or proposed reservoir ponds east and west of city center. Several outlets in the master plan act to reduce cost-inducing earth works and allow the storm water drainage to discharge with minimum slope considering the flat nature of the terrain. Alternatives were designed and evaluated to cover projected urban developments around city center with provisions for additional dike construction, rehabilitations of existing culverts and extension to some of the channels. 1 Ondjiva City elevation contours 2 Emergency relief flood mitigation dikes constructed in 2009 3 Contained flood after dike construction and culvert rehabilitation 44