Understanding anastomosed landscapes through satellite and Indigenous eyes: A Nguku-Cooper Creek case study

Abstract

The Nguku/KaRirra-Cooper Creek/Wilson River Confluence of the Kati Thanda (Lake Eyre) Basin, like many dryland water resources and associated ecologies, is increasingly under pressure from human activity and climate change. Sustainable water management requires quantitative monitoring of what is happening and when, why and how the effects are occurring, and who or what is causing change (positive or negative). This is especially difficult for such a temporary and heavily anastomosed river reach, due to its extreme natural variability, multi-year climate cycles, poorly tracked and slowly-responding ecology, sparse-instrumentation, and problematic access.

Technical data about the Confluence can be sourced from measurements and satellite imagery, including 30 years of Landsat spectral data, verified during field expeditions. But technical data, with its limited duration, sampling frequency and extent, can only tell part of the story.

A complementary source of information about the Confluence is the human lived experience, in the form of cultural stories that communities tell about their environment. The Indigenous Environmental Knowledge of the Wangkumara people of the KaRirra-Wilson River covers all parts of the Confluence hydrological cycle and interrelates it with cultural, historic, and ecological information. European accounts of exploration, re-naming, and settlement of the Nguku/KaRirra-Cooper Creek/Wilson River region from the 1800s to the present day are accessible through contemporaneous writings and maps and archives. Interviews with long-term residents provide information about more recent events. Archaeological studies further underpin knowledge that may hark back centuries or longer.

This thesis develops a Worldview Methodology to address some of the major ethical and methodological challenges for academic researchers when accessing social and particularly Indigenous knowledge due to different systems of knowledge management and control, to promote appropriate use of Indigenous and other social knowledge in this contemporary hydrological study.

The complicated Confluence landscape is systematized using Landscape Units, and its convergent/divergent drainage network is ordered by Extended Stream Order/Magnitude. Surface status is classified at pixel level using a three-way Water/Bare/Vegetated method, reflecting the significance of vegetation in tracking moisture. At feature level, waterholes are quantitatively assigned Permanent/ Intermittent/Ephemeral classifications. And at landscape level, Ribbon Plots illustrate spatial and statistical water presence over time along selected paths or transects.

Using these tools to combines technical data, fieldwork, and Indigenous and social knowledge, this thesis tells a quantified cultural story of long-term water behaviour at the Nguku/KaRirra-Cooper Creek/Wilson River Confluence. It investigates three claims by current Confluence residents of flow behaviour changes as a result of construction work, plus one hydrological examination of a Wangkumara Story, quantifying how the journey of ancestral spirit Marnpi the Bronzewing Pigeon across a difficult arid landscape identifies persistent waterholes and other ecological features.

The examples in this thesis show how interpretation of technical data can be improved by integration with the human lived experience via cultural stories. More broadly, the principles and methods can be applied to any multiple-channel, intermittent, or dryland system, allowing for more informed and inclusive environmental management. Ultimately, it shows social knowledge and Indigenous Environmental Knowledge are relevant to well-informed environmental management.