Water security and soil sealing

There is a lake in San Joaquin Valley – or there was one once. It was the largest lake in the valley, but by 1899 the lake was a dry bed except for some surrounding wetlands and during occasional flooding.

Water entering the lake began to be diverted from feed rivers upstream to serve the growing municipal and agricultural needs of 100 years ago. River water stopped replenishing the lake and was used to irrigate crop farms in the California Valley, which is famous as America’s most valuable farming region.

Today, crops from the area form a large part of big agro-company supply chains. Apart from standard crops like carrots and tomatoes, other high-value farm produce is grown. Pistachios, almonds, table grapes and pomegranates are shipped across the continent and exported overseas. Local farmers’ markets also depend on these crops, which are grown on family farms.

With less snow in the nearby Sierra mountain range, San Joaquin Valley farmers are now facing volatile runoff patterns and less of a steady yet gentle melt.

Earlier this month, the Union of Concerned Scientists descended on California’s state university to hold a forum on the recent climate change impacts in the valley. Climate is already seen to be having an effect on the southern half of the central valley, which has served as a cornucopia for over a century.

The valley’s future is threatened by a worsening of water scarcity, wildfires and insect vectors, which threaten not only the area’s economy but also the national food supply. With the area’s population still growing, concerns over water and energy pose additional challenges.

A simple factor that makes this valley one of the world’s most fertile regions outside the Nile river basin is the wide range between daily highs and lows of temperature with benefits for many crops.

Scientists warn that in this scenario, warming of temperatures at the high end of the scale is less worrying than spikes at the lower range. Speaking at the Fresno State meeting, associate professor of earth and environmental science Peter Van de Water told of the disturbing observation that low temperatures are warming.

He observed that a changing temperature pattern could cause long-term harm for the sector, which is the basis of the region’s economy, adding that climate adaptation had to start now.

The forum concluded that the region will have to increase its water security. Soft options ad­dressing water consumption, such as rainwater capture and conservation, will not be enough on their own to address the valley’s water challenges. With groundwater supplies depleting, it will be necessary to find better storage strategies or turn to hard options such as increasing groundwater storage and building additional reservoirs.

Technology will have to play a role as the region tries to balance increased global demand for food with tighter water supplies. Sensors offering real-time information about water quality and supplies may prove useful in this case.

Understanding earth systems is essential to human health and environmental protection. Europe’s global monitoring programme (GMES), renamed Copernicus, is an EU initiative with the European Space Agency.

One trend being watched from above is the rate of ‘soil sealing’, or covering over of soil by buildings, roads and other impervious surfaces, making it no longer available for rain to pass through or biodiversity to thrive.

The economic and environmental consequences of soil sealing are poorly understood.

Two important functions of soil are keeping carbon out of the atmosphere and helping to filter water as it percolates down into the aquifer. Yet much of Europe’s soil is being replaced by artificial surfaces due to urban expansion.

The state authority for mining, energy and geology is responsible for soil protection and has used Copernicus to inform its management of land resources and strategy for adapting to climate change.

Data by geographic information provider Infoterra and the remote-sensing consultancy Geoville has provided compelling input for spatial planning with soil conservation in mind.

In Lower Saxony, Germany, where most land is used for agriculture and farming, changes to land use that threaten soil are regulated under federal and state laws. This came about after a decade of soil-sealing in the 1990s when over five hectares were lost each day.

Planning staff at the department for agriculture and soil conservation in the region have been working with geographic information and remote-sensing to map the entire state of Lower Saxony.

The European Commission is working with 88 participating governments to extend the network of earth observation systems.

Air app

A new air quality system is now available as an iPhone app, providing real-time information on air quality in Europe.

Forecasts and warnings about the levels of pollutants, such as nitrogen dioxides, ozone and particulate matter, will soon be available in near real-time.

The obsAIRve service is part of the global monitoring system for environment and security funded by the European Commission.

Air quality data disseminated by obsAIRve is mainly from participating cities and from the relevant GMES projects.


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