Mfolozi floodplain flood management

Mfolozi floodplain flood management

Van Loon, P.
Olij, D.
Osmanoglou, D.
Stuij, S.
Tuinhof, T.
Veraart, S.

Civil Engineering and Geosciences

Hydraulic Engineering

2013-04-01

The Mfolozi Floodplain is situated in the province of KwaZulu-Natal in South Africa and is part of Africa’s largest estuarine system: the St Lucia system. This estuarine system forms the main part of the iSimangaliso Wetland, which is a World Heritage Site of UNESCO. Since the beginning of the twentieth century the Mfolozi Floodplain is under intensive sugarcane cultivation. This sugarcane cultivation has led to different management strategies of the Mfolozi River and mouth. The mouth of the Mfolozi River has been separated from the St Lucia Mouth for a long period, which led to hyper saline conditions in the St Lucia Lake in times of drought. To guarantee fresh water supply to the St Lucia system the estuary is recently (July 2012) connected to the Mfolozi Mouth via a Beach Channel, resulting in a system with a single shared mouth. If this mouth is closed water backs up on the Mfolozi Floodplain. The main goal of this project can be defined as: “Investigation and development of a flood management system for the Mfolozi Floodplain, considering the fresh water supply to the St Lucia Lake in times of drought.” An important issue for the development of this flood management system is the presence of two groups of stakeholders with conflicting interests. The first group is the ‘green’ group that consists of the iSimangaliso Wetland Park Authority, Ezemvelo KZN Wildlife and the GEF project. The management part of the park is done by the iSimangaliso Wetland Park Authority and the executive part by Ezemvelo KZN Wildlife. In 2008 the iSimangaliso Wetland Park Authority was granted a trust fund by the Global Environmental Facility (GEF) to investigate and improve the management strategy for the St Lucia system. The second group is the ‘blue’ group that consists of the UCOSP, USM and the local farmers. The UCOSP provide tramline transport of sugarcane from the farms to the sugar mill (USM) and manages the flood protection infrastructure on the Mfolozi Floodplain. The main problem is that the ‘blue’ group wants to breach the mouth at a certain level to prevent the farmland of flooding, where the ‘green’ group wants to leave the opening and closing process of the mouth to nature to guarantee a natural estuarine functioning of the St Lucia system.

floodplain
flood risk
backwater
river mouth

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