African Wildlife and Environment Issue 68

CONSERVATION

CONSERVATION

Managed Aquifer Recharge (MAR) is widely used to store surface water underground, but also to prevent the salt water intrusion into the aquifer, as heavy abstraction alters the interface between salt and fresh water in what is known as the Ghyben-Herzberg Principle. One of the unintended consequences of this is a rising water table, even as the salt water intrusion is kept at bay. Trade-offs need to be fully understood by decision-makers when making hard choices about sustainability over time. This is where it becomes interesting and relevant to South Africa. From my own observations as a guest of the Burdekin Water Forum, there are at least three lessons to be learned: 1. When altering fundamental hydrological parameters such as flood pulse of surface water flows, and abstraction of groundwater on a vast

deficits by 2025, based on the High Scenario of the first National Water Resource Strategy published in 2004, mandated by the newly promulgated National Water Act (1998), by specific Water Management Area (WMA) are as follows: • Upper Vaal WMA will have a deficit of 764 million cubic meters per annum. • The Mvoti – Mzimkulu WMA will have a deficit of 788 million cubic meters per annum.The Berg WMA will have a deficit of 508 million cubic meters per annum. • The only WMA to be in surplus is the Crocodile West – Marico, with a projected flow of 335 million cubic meters per annum, mainly sewage return flows out of Gauteng. • The combined national deficit will be 2 044 million cubic meters per annum.

Water lessons from AUSTRALIA

Anthony Turton

I was recently invited to participate in the Burdekin Water Forum, hosted by the Water Futures Group in the small but beautiful town of Ayr. Located in the Shire of Burdekin, Queensland, Australia. This was an eye-opening event for me as a South African scientist working on water related strategies.

and sustained basis, it is extremely important to have a reliable and all-encompassing monitoring system in place. 2. The second major lesson is that the Australian government at national level, the state government at middle tier level, and the local government at shire level are all deeply respectful of science and the contribution that can bemade by academic institutions. 3. When speaking of integrated water resource management, it is vital to understand the interaction of both surface and groundwater flows, as well as the linkages arising from those flows with the ocean. The Great Barrier Reef is globally significant, and it is in severe distress, caused by a complex set of drivers including an altered

The Burdekin River has many tributaries, feeding water from the monsoon into the ocean, in the vicinity of the Great Barrier Reef. The basin is in the dry tropics, which receives over 1 000 mm of rainfall per annum, but this falls in just three to four months. The rest of the year is very hot and dry. It lies adjacent to the Ross River, flowing to the ocean near the city of Townsville, and epicenter of the notorious Ross River Virus.

environments. Home to salt water crocodiles, and a complex array of billabongs, it is also blessed with highly fertile soil of great depth. In the 1920s a group of Italian cane cutters migrated there, partly driven by the rise of fascism in Europe, but also drawn by the needs for labour in the recently-created sugar cane industry. Today almost all the residents of the Burdekin Shire are descendants of, or intermarried with, those hard-working and industrious cane cutters. The total population of the Burdekin Shire is around 18 000 living across the roughly 5 000 square kilometers of fertile and well-watered land. The population density is very low at around 3.6 people per square kilometer. With such a low population density it is a great surprise to see the massive impact they have had on the original pristine environment. In just four generations, this small population of diligent cane cutters have become prosperous cane farmers, but they have also fundamentally altered the ecological systems. What used to be a complex array of inter locking billabongs, sustaining an area of great biodiversity in a massive wetland system driven by a distinct annual flood pulse, has now become a steady state system maintained by the Burdekin Falls Dam, also known as Lake Dalrymple. When it was commissioned in 1988 it held back the significant floods, and allowed irrigation on a major scale. Irrigation comes from both surface water and groundwater, given that the entire basin is in effect an ancient alluvial aquifer that stores vast quantities of water. This in turn enabled more land to be cleared, more cane to be grown, and as an unintended consequence, altered the fresh water / salt water interface in the lower parts of the basin. The best available information from the Commonwealth Scientific and Industrial Research Organization (CSIRO) suggests that the water table is steadily rising, and the land will become waterlogged within the next decade if nothing is done about it.

The First National Water Resource Strategy published in 2004 provided the highest level of confidence available and projected specific deficits by 2025

flood pulse, agrochemical flows from intensive farming, and the growing intensity of tropical cyclones driven by global warming. It is also the canary in the cage down a mineshaft, because it has triggered massive amount of scientific research. Located in various institutions, I visited the James Cook University (JCU) in Townsville, and the CSIRO office located on the campus. Cooperative research, adequately funded from multiple sources, has made these two institutions world leaders in their field. But more importantly, there is a respect for, and intimate contact between all scientists working in those two institutions, and all levels of government decision makers. This is the big lesson for South Africa. Currently the local water sector is in severe crisis. The known

Unlike in the Burdekin case, scientists were ignored in South Africa. When the major El Nino drought hit with all its fury in 2015-16, KZN was decimated and Gauteng came to within a few days of losing its supply of water. Parts of KZN, such as the Ugu district centered on Port Shepstone, have never recovered. What is now being reported by the City of Cape Town as being ‘Day Zero’ – that specific moment in time when water stops flowing in the taps – has been in existence at places like the Murchison Hospital since 2015, despite the drought having been broken in that specific province. Cape Town, located in the Berg WMA, is now in the grips of the worst drought in recorded history, with best available information suggesting that Day Zero will be in March 2018.

Map of Burdekin River Basin (courtesy of James Cook University)

The Burdekin is an ‘interesting’ river. Just four human generations ago, it was a vast natural wetland linking the dry hinterland of the continent with the globally unique Great Barrier Reef. Flood pulses and nutrient flows are critical drivers of ecological processes in both terrestrial and oceanic

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