Smart Water Management Matters

'Nature-based solutions' key to water management: UN report - World Water Day 22 March.

Wednesday, 21 March, 2018

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Nature-based solutions can play an important role in improving the supply and quality of water and reducing the impact of natural disasters, according to the 2018 edition of the United Nations World Water Development Report.

Presented at the 8th World Water Forum this week by UNESCO Director-General Audrey Azoulay and UN-Water Chair Gilbert Houngbo, the study argues that reservoirs, irrigation canals and water treatment plants are not the only water management instruments at our disposal.

In 1986, the State of Rajasthan (India) experienced one of the worst droughts in its history. Over the following years, an NGO worked alongside local communities to set up water harvesting structures and regenerate soils and forests in the region. This led to a 30% increase in forest cover, groundwater levels rose by several metres and cropland productivity improved.

These measures are examples of the nature-based solutions (NBS) advocated by the latest edition of the report, ‘Nature-based Solutions for Water’. It recognises water not as an isolated element, but as an integral part of a complex natural process that involves evaporation, precipitation and the absorption of water through the soil. The presence and extent of vegetation cover across grasslands, wetlands and forests influences the water cycle and can be the focus for actions to improve the quantity and quality of available water.

“We need new solutions in managing water resources so as to meet emerging challenges to water security caused by population growth and climate change,” said Azoulay. “If we do nothing, some 5 billion people will be living in areas with poor access to water by 2050. This report proposes solutions that are based on nature to manage water better. This is a major task all of us need to accomplish together responsibly so as to avoid water-related conflicts.”

“For too long, the world has turned first to human-built, or ‘grey’, infrastructure to improve water management,” Houngbo said in the foreword of the report. “In so doing, it has often brushed aside traditional and Indigenous knowledge that embraces greener approaches. Three years into the 2030 Agenda for Sustainable Development, it is time for us to re-examine nature-based solutions (NBS) to help achieve water management objectives.”

Focusing on ‘environmental engineering’

So-called ‘green’ infrastructure, as opposed to traditional ‘grey’ infrastructure, focuses on preserving the functions of ecosystems, both natural and built, and environmental engineering rather than civil engineering to improve the management of water resources. This has multiple applications in agriculture, the greatest consumer of water by far. Green infrastructure can help reduce pressures on land use while limiting pollution, soil erosion and water requirements by contributing to the development of more effective and economic irrigation systems, for example.

Thus, the System of Rice Intensification, originally introduced in Madagascar, helps restore the hydrological and ecological functioning of soils rather than using new crop varieties or chemical products. It enables savings of 25 to 50% in water requirements and 80 to 90% in seeds while raising paddy output by 25 to 50%, depending on the region in which it is implemented.

It is estimated that agricultural production could be increased by about 20% worldwide if greener water management practices were used. One study cited by the report reviewed agricultural development projects in 57 low-income countries and found that using water more efficiently, combined with reductions in the use of pesticides and improvements in soil cover, increased average crop yields by 79%.

Green solutions have also shown great potential in urban areas. While vegetated walls and roof gardens are perhaps the most recognisable examples, others include measures to recycle and harvest water, water retention hollows to recharge groundwater and the protection of watersheds that supply urban areas. New York City has been protecting its three largest watersheds since the late 1990s. Disposing of the largest unfiltered water supply in the USA, the city now saves more than US$300 million yearly on water treatment and maintenance costs.

Faced with an ever-increasing demand for water, countries and municipalities are showing a growing interest in green solutions. China, for example, recently initiated a project called ‘Sponge City’ to improve water availability in urban settlements. By 2020, it will build 16 pilot Sponge Cities across the country. The goal is to recycle 70% of rainwater through greater soil permeation, retention and storage, water purification and the restoration of adjacent wetlands.

The importance of wetlands

Wetlands only cover about 2.6% of the planet but play a disproportionately large role in hydrology. They directly impact water quality by filtering toxic substances from pesticides, industrial and mining discharges.

There is evidence that wetlands alone can remove 20 to 60% of metals in water and trap 80 to 90% of sediment from runoff. Some countries have even created wetlands to treat industrial wastewater, at least partially. Over recent years, Ukraine, for example, has been experimenting with artificial wetlands to filter some pharmaceutical products from wastewater.

However, ecosystems alone cannot perform to totality of water treatment functions. They cannot filter out all types toxic substances discharged into the water and their capacity has limits. There are tipping points beyond which the negative impacts of contaminant loading on an ecosystem become irreversible, hence the need to recognise thresholds and manage ecosystems accordingly.

Mitigating risks from natural disasters

Wetlands also act as natural barriers that soak up and capture rainwater, limiting soil erosion and the impacts of certain natural disasters such as floods. With climate change, experts predict that there will be an increase in the frequency and intensity of natural disasters.

Some countries have already started taking precautions. For example, Chile announced measures to protect its coastal wetlands after the tsunami of 2010. The State of Louisiana (USA) created the Coastal Protection and Restoration Authority following Hurricane Katrina (2005), whose devastating impact was magnified by the degradation of wetlands in the Mississippi Delta.

Nevertheless, the use of nature-based solutions remains marginal and almost all investments are still channelled to grey infrastructure projects. Yet, to satisfy the ever-growing demand for water, green infrastructure appears to be a promising solution complementing traditional approaches. The authors of the report therefore call for greater balance between the two, especially given that nature-based solutions are best aligned with the Sustainable Development Goals adopted by the United Nations in 2015.

Coordinated by the World Water Assessment Programme of UNESCO, the United Nations World Water Development Report is the fruit of collaboration between the 31 United Nations entities and 39 international partners that comprise UN-Water. Its publication coincides with World Water Day, celebrated every year on 22 March.

Image credit: ©stock.adobe.com/au/Zffoto

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Some thoughtful ideas that should be considered more often, even in Australia.  Unfortunately it often cuts across the old engineering concepts and old ideas are hard to change.  It also tends to have longer time frames to see change and involves more community groups to develop meaningful ideas.

Neonicotinoids - EU Ban Possible ?

This insecticide class has been under threat for some time mainly due to the damage possibly caused to bees, a valuable component in crop production of broadacre field crops and in horticulture.

In the EU the products cannot be used on major bee activity crops - eg sunflowers, oilseed rape and maize -  now.

But a recent report is advocating a broader approach and a ban across the  EU might be an option that could be considered, at least outdoors.

More rationale discussion is canvassed here -
https://www.scientificamerican.com/article/e-u-expected-to-vote-on-pesticide-ban-after-major-scientific-review/?utm_source=newsletter&utm_medium=email&utm_campaign=sustainability&utm_content=link&utm_term=2018-03-01_featured-this-week

Given the importance of bees in the production of fruit and seed in many species most growers are careful with most insecticides, but problems can arise, and with this class of chemical  the active ingredient does seem to persist and move within the plant.

Eradicating Mosquitoes - Without Trying

Yes, in the world of science there are some things that occur when unexpected.

This has been a fortutious positive effect in which rat eradication on a remote island chain has resulted in eradication of mosquitoes too.

Read more below.  Something very positive!

If only eradicating Asian tiger mosquitoes was always that easy..........but hey, with many populations of rats on islands now highly targetted for eradication, will we see more positive side effects in warmer regions?

Is there a message in this success that could be replicated on some of Australia's offshore islands where this mosquito occurs too, by targetting rats? 

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Paradise Regained: How the Palmyra Atoll Got Rid of Invasive Mosquitoes

The elimination of the biting pests was an added bonus after researchers unleashed a rat-eradication endeavor on the tiny islands.  

By Ruth Williams | February 28, 2018

Palmyra AtollKEVIN LAFFERTYOne thousand miles south of Hawaii, the Palmyra Atoll, a horseshoe-shaped chain of islets, is about as isolated as you can imagine, says Erin Mordecai, a biologist at Stanford University who has visited the islets to conduct ecology research. “It’s really, really remote and has never had a native human population,” she says. Year-round, the population varies between approximately five and 30 people—generally, scientific researchers and Nature Conservancy staff.

But the atoll is far from unspoiled, Mordecai continues. “The most human impact it’s had was during World War II when there were about 2,400 troops.” Considering the brevity of the soldiers’ inhabitation, the repercussions were immense. “They built airstrips on some of the islands. There’s still metal and debris that they left behind.” They also brought rats and mosquitoes, neither of which is native to the atoll. There are in fact no native mammals and only a few native insects.

With no predators and plenty of food, the rat population exploded. In 2011, it was estimated to have reached 40,000. “There’s not a lot of land . . . [so] they were everywhere,” says wildlife refuge manager Stefan Kropidlowski of the US Fish and Wildlife Service in Honolulu who oversees research visits to the atoll. Kropidlowski had not visited Palymra before the eradication, but “by all accounts,” he says, “if you walked though the jungle, they were in the trees, they were jumping up around you, they were crawling through the cabin screens at night, and it was a huge hassle to store food.”

From a conservation perspective, Kropidlowski says, “the rats were predating a lot of the seabirds and probably resulted in the extirpation of a number of ground-nesting [species].” So, when the atoll became a National Wildlife Refuge in the early 2000s, he says, “rat eradication was one of the major conservation priorities . . . to give the seabirds a chance to start coming back.”

Sea birds flying over Palmyra AtollKEVIN LAFFERTY

A 2011 atoll-wide rat-poisoning endeavor successfully eliminated the rodents, and, in the following years, conservation researchers documented the effects to the native wildlife. Among these scientists was Kevin Lafferty of the US Geological Survey and the University of California, Santa Barbara, who led the research. “We were looking at how the food web was changing after rat removal,” he explains.

But of course, “we were part of the food web,” says Lafferty. “Getting bitten by mosquitoes is the price you pay for working in paradise.” Therefore, after the rodent eradication, it became “just obvious that we weren’t being bitten [during the day] anymore.”

As Lafferty and his colleagues report in Biology Letters today (February 28), not a single Asian tiger mosquito (Aedes albopictus) has been found on Palmyra Atoll during a recent two-year survey. This unanticipated secondary extinction serves as a reminder of the interdependency and fragility of species within ecosystems.

“This is an interesting paper that opens up the fascinating possibility that eradicating one human-introduced pest, which would be the rats, could lead to the secondary elimination of another human-introduced pest, A. albopictus,” says entomologist Megan Fritz of the University of Maryland who was not involved with the study. “The findings have implications for conservation biology and habitat restoration and possibly even human health in sparsely populated tropical island communities.”

Indeed, “this study highlights an often under-sung impact of invasive species—disease vectoring,” Alex Wegmann, the Palmyra program director at the Nature Conservancy in Honolulu who was not involved with the study, writes in an email to The Scientist. “Rats do not carry yellow fever, but, in this case, they allowed the pathogen’s primary vector to persist at Palmyra for decades.”

Starving mosquitoes to death

A. albopictus, one of the two mosquito species on the atoll, bites during the day and feeds preferentially on mammals, but can also bite birds. The other, Culex quinquefasciatus, bites at night and feeds preferentially on birds, but can also bite mammals. Without the rats, it was thought that A. albopictusmight bite birds and humans more often. “We hadn’t predicted that the mosquitoes would [die out],” Lafferty says.

After the rat eradication, researchers started noting how pleasant their trips had been, says Lafferty. Kropidlowski recalls his first visit to the atoll, a few years after the rodents were wiped out. “I had been told to expect lots of mosquitoes,” he says “but there were none.” He remembers noticing old bottles of insect repellent, gathering dust, unfinished.

The idea arose that perhaps the mosquitoes might have starved to death. “Normally, you come up with an idea like that and it just remains an idea,” Lafferty says. But, as luck would have it, Lafferty’s colleague at the University of California, Santa Barbara, and coauthor on the study, Hillary Young, had data on flying insects, including mosquitoes, that predated the rat eradication.

“It was very serendipitous and not planned or expected,” says Lafferty.

Because the researchers would still occasionally be bitten at night, the question was, had the daytime-biting, mammal-preferring A. albopictus really been wiped out? Lafferty’s team went to great lengths to try to capture members of the species—setting two different types of trap—before concluding that, yes, by the standards set by the World Health Organization (two years of sensitive surveillance without detection), A. albopictus was indeed gone.

It was clear the mosquitoes hadn’t switched to feeding more often on birds and humans, at least not in sufficient numbers to support the population. And there was another factor that the authors speculate may have contributed to the mosquitoes’ demise. Without the rats, there were far fewer freshwater receptacles in which mosquito larvae could hatch. The rodents would gnaw coconut shells in half, to eat the innards, and leave them littered about the islets, catching rainwater.

It would be nice to think that in areas with more people, such as cities, rat eradication might also eliminate mosquitoes, but this seems unlikely, says Fritz. “The modelling results from the paper suggest that larger human populations would likely be able to sustain A. albopictus populations.”

“I don’t think the main message of this paper is that we’ll be able to eradicate rats to get rid of mosquitoes,” agrees Lafferty. “The more important message is . . . the interdependence of species.”

If a species is driven to extinction, he says, “are we just going to lose that one species . . . or could we lose many? Even though we’re talking about two species we don’t like, here, it could just have easily been two species we did like. It could have been, for instance, an endangered flower and its pollinator.”

K.D. Lafferty et al., “Local extinction of the Asian tiger mosquito (Aedes albopictus) following rat eradication on Palmyra Atoll,” Biol Lett, doi:10.1098/rsbl.2017.0743, 2018.

Warm Autumn ?- Could Still Plant Compadre Zoysia Seeded Lawn

The latest medium term climate notices issued on 28 February 2018 for March - May [ ie Australian autumn period] are predicting warmer days and nights for much of Australia in this Autumn period.

A more detailed map and analysis is available on the site http://www.bom.gov.au/climate/outlooks/#/temperature/maximum/median/seasonal/0 

Much of Australia is likely to be warmer over the next 3 months, both days and nights.

This presents an extended opportunity to get a new seeded zoysia turf area started and probably well matured in this period, rather than waiting for late next spring. However, it is prudent if considering this option, to get sowing under way in the next month or so to capitalise on the warmer weather.  Opportunities also are better if in north Australia, to start an area, mostly missing the very wet periods of the monsoon weather that can cause erosion and management issues for new areas.

Compadre zoysia seed still available - contact office@abovecapricorn.com.au for further information and pricing.  We also have a seres of information sheets available for establishing and maintaining zoysia turf in pdf electronic format - just ask!