Applying a resilience approach to flood management in rapidly changing landscapes

Thesis (PhD)--Stellenbosch University, 2016.ENGLISH ABSTRACT: Human land use activities have significantly changed the capacity of ecosystems to deliver essential service. Additional stresses brought about by climate change will require a shift in how ecosystems are managed. Global increases in the magnitude and frequency of flood events in particular have raised concerns that traditional flood management approaches may not be sufficient to deal with future uncertainties. Resilience approaches aimed at understanding and managing the capacity of social-ecological system (SES) to adapt to, cope with, and shape uncertainty and surprise offer a possible avenue to deal with these challenges. Accordingly, through the use improved systems approaches and knowledge on floods, flood regulation services and its impact on people and infrastructure this dissertation contributes towards developing and piloting of a flood resilient management strategy. Research was carried out using three flood prone municipalities in the Eden District of South Africa as a case study. The Millennium Ecosystem Assessment, in its final report, highlighted regulating services as some of the most important and degraded, but least understood ecosystem services. Regulating services moderate the flow of energy and materials and play a critical role in regulating the impacts of extreme events. The progress in research and understanding of regulating services was investigated, with a particular focus on progress on their assessment and quantification. Findings flag key research gaps in all regulating services in developing countries and globally, in specifically understudied regulation services of disease regulation and air quality regulation. Results also revealed the need to include the human dimension into the study of regulating services, which will require an increase of multi-disciplinary research using a social-ecological system approach. Based on these findings and the objectives of the study the use of an existing decision support tool SCIMAP was adapted and explored using globally available data to provide a practical and informative approach for identifying flood receiving areas at a watershed scale. Model outputs highlighted how the combined effect of natural and anthropogenic factors can aggravate or attenuate a flood event, adding valuable insights into flood generation and how it can be managed, especially in under resourced areas. In order to assess the resilience of communities to floods, a composite index and spatial analysis approach was piloted. The approach allows for a simple, yet robust index able to include an array of datasets generally available in flood prone areas with potential to disaggregate and trace variables for management and decision making. Finally, based on the methods and results developed in previous chapters of the dissertation, an approach to characterise and spatially connect the flood regulating ecosystem service flows from supply to demand is introduced and illustrated. The proposed method builds on from the thinking in flood vulnerability and incorporates landscape connections from supply to demand areas. By identifying and linking supply areas to the downstream benefitting areas of the watershed, areas directly linked to high demand can be conserved to ensure a sustainable supply of the flood regulation service. This dissertation provides new and improved approaches for building and managing flood resilient watersheds. The results have immediate applicability to landscape managers in areas where data for process-based models and the capacity to interpret model outputs may be limited.AFRIKAANS OPSOMMING: Menslike grondgebruik aktiwiteite het die kapasiteit van ekosisteme om noodsaaklike dienste te lewer aansienlik verander. Bykomende spanning as gevolg van klimaatsverandering noodsaak 'n verskuiwing in hoe ekosisteme op die oomblik bestuur word. Globale stygings in die grootte en frekwensie van vloede in besonder wek kommer dat tradisionele vloed bestuursbenaderings nie voldoende sal wees om toekomstige onsekerhede te verweer nie. Veerkragtigheid benaderings wat gemik is op die verstaan en bestuur van die kapasiteit van sosiaal-ekologiese sisteeme (SES) om aan te pas verassings te hanteer, en onsekerheid te verweer bied 'n moontlike oplossing om met hierdie uitdaging om te gaan. Gevolglik, deur die gebruik van 'n verbeterde stelsels benaderings en kennis oor vloede, sovel as oorstromings regulasie dienste en die impak daarvan op mense en infrastruktuur dra hierdie dissertasie by tot die ontwikkeling en bekendstelling van 'n vloed veerkragtig bestuurstrategie. Navorsing is uitgevoer met behulp van drie vloedliggende munisipaliteite in die Eden Distrik van Suid-Afrika as 'n gevallestudie. In die finale verslag van die Millennium Ecosystem Assessment, is uitgelig dat regulering dienste een van die belangrikste en vervalle, maar die minste begrypte ekosisteem dienste is. Regulering van dienste matig die vloei van energie en materiaal en speel 'n kritieke rol in die regulering van die impak van ekstreem gebeure. Die vooruitgang in navorsing en begrip van die regulering van dienste is ondersoek, met 'n besondere fokus op die vordering van bepaling en kwantifisering. Bevindinge lê klem op sleutel navorsing gapings in al die regulering dienste in ontwikkelende lande sowel as wêreldwyd, in besonder, onder-bestudeerde regulasie dienste van siekte regulering en luggehalte regulasie. Resultate onthul ook die behoefte om die menslike dimensie in die studie van regulering dienste in te sluit, dit beteken dat 'n toename van 'n multi-dissiplinêre navorsing met behulp van 'n sosiaal-ekologiese sisteem benadering sal benodig word. Op grond van hierdie bevindinge en die doelwitte van die studie is die gebruik van 'n bestaande besluit ondersteunings model SCIMAP aangepas en verken met behulp van globaal beskikbare data om 'n praktiese en insiggewende benadering vir die identifisering van vloed ontvangs areas op'n waterskeiding skaal te verkry. Model resultate lig uit hoe die gekombineerde effek van natuurlike en menslike faktore vloed gebeurtenis kan vererger of verswak, en voeg waardevolle insigte vir hoe dit bestuur kan word, veral in gebiede waar daar'n tekort aan hulpbronne is. Met die doel om die veerkragtigheid van gemeenskappe gedurende vloed gebeure te evalueer, is 'n saamgestelde indeks en ruimtelike analise benadering geloods. Die benadering maak voorsiening vir 'n eenvoudige, maar kragtige indeks in staat om 'n verskeidenheid van datastelle oor die algemeen beskikbaar in vloedliggende gebiede te gebruik met die potensiaal om gesky te word en veranderlikes op te spoor vir bestuur en besluitneming. Ten slotte, gebaseer op die ontwikkelde metodes en resultate in die vorige hoofstukke van die dissertasie word 'n benadering gebruik om vloed regulering ekosisteem diens vloei te karakteriseer en ruimtelik te verbind van toevoer tot by aanvraag. Die voorgestelde metode is gebaseer op die denke in vloed kwesbaarheid en sluit landskap verbindings van die toevoer en aanvraag gebiede in. Deur die identifisering en skakeling van toevoer areas aan aanvraag areas in die stroomaf gebied van die waterskeiding, kan gebiede direk gekoppel aan 'n groot aanvraag bewaar word, om 'n volhoubare voorsiening van die vloed regulasie diens te verseker. Die dissertasie bied nuwe en verbeterde benaderings vir die bou en bestuur van vloed veerkragtig in waterskeidings. Die resultate het onmiddellike toepaslikheid tot landskap bestuurders in gebiede waar data vir-proses modelle en die vermoë om model resultate beperk mag wees te interpreteer