Road salt, development blamed for spiking chloride levels
Lakes from New England to the Midwest are getting saltier from the massive use of chemicals to melt ice on roads, as well as from urban development. Under the current trend, many North American lakes will surpass EPA-recommended chloride levels in 50 years, spelling trouble for aquatic ecosystems.
New study shows warmup will boost methane releases
Small ponds could end up having a huge impact on Earth’s climate as they warm up due to heat-trapping greenhouse gas pollution, according to scientists from the University of Exeter and Queen Mary University of London. The researchers experimentally warmed a number small ponds by about 4-5 degrees Celsius over the course of seven years to study the effects of increased temperatures. Continue reading “How do ponds fit into the global warming equation?”→
In what is probably one of the EPA’s final moves before the Trump era starts, the agency this week released a new study showing how fracking can affect drinking water. There’s nothing in the report that wasn’t already known to scientists, water managers and health experts, but the fact that the EPA finally acknowledged the potential impacts is important, according to environmental advocates.
As part of the report, EPA identified conditions under which impacts from hydraulic fracturing activities can be more frequent or severe, including:
Water withdrawals for hydraulic fracturing in times or areas of low water availability, particularly in areas with limited or declining groundwater resources;
Spills during the management of hydraulic fracturing fluids and chemicals or produced water that result in large volumes or high concentrations of chemicals reaching groundwater resources;
Injection of hydraulic fracturing fluids into wells with inadequate mechanical integrity, allowing gases or liquids to move to groundwater resources;
Injection of hydraulic fracturing fluids directly into groundwater resources;
Discharge of inadequately treated hydraulic fracturing wastewater to surface water resources; and
Disposal or storage of hydraulic fracturing wastewater in unlined pits, resulting in contamination of groundwater resources.
The report also identifies uncertainties and data gaps. These uncertainties and data gaps limited EPA’s ability to fully assess impacts to drinking water resources both locally and nationally. These final conclusions are based upon review of over 1,200 cited scientific sources; feedback from an independent peer review conducted by EPA’s Science Advisory Board; input from engaged stakeholders; and new research conducted as part of the study.
“The value of high quality science has never been more important in helping to guide decisions around our nation’s fragile water resources. EPA’s assessment provides the scientific foundation for local decision makers, industry, and communities that are looking to protect public health and drinking water resources and make more informed decisions about hydraulic fracturing activities,” EPA science advisor Thomas A. Burke said in a press release. “This assessment is the most complete compilation to date of national scientific data on the relationship of drinking water resources and hydraulic fracturing.”
The report is organized around activities in the hydraulic fracturing water cycle and their potential to impact drinking water resources. The stages include:
acquiring water to be used for hydraulic fracturing (Water Acquisition),
mixing the water with chemical additives to make hydraulic fracturing fluids (Chemical Mixing),
injecting hydraulic fracturing fluids into the production well to create and grow fractures in the targeted production zone (Well Injection),
collecting the wastewater that returns through the well after injection (Produced Water Handling), and,
managing the wastewater through disposal or reuse methods (Wastewater Disposal and Reuse).
The agency said that information gaps remain because, in some cases, needed data isn’t collected, isn’t available publicly or difficult to aggregate.
In places where the agency knows activities in the hydraulic fracturing water cycle have occurred, data that could be used to characterize hydraulic fracturing-related chemicals in the environment before, during, and after hydraulic fracturing were scarce.
“Because of these data gaps and uncertainties, as well as others described in the assessment, it was not possible to fully characterize the severity of impacts, nor was it possible to calculate or estimate the national frequency of impacts on drinking water resources from activities in the hydraulic fracturing water cycle,” the EPA wrote in a press release. Read the study here: www.epa.gov/hfstudy.
In just two years following a man-made flood in the Colorado River Delta, cottonwoods and willows have grown 10 feet tall, rebuilding habitat for other native plants and animals, according to a new monitoring report on the international experiment to re-water the long-arched region.
Some climate models project more rainfall in the West
While most recent research suggests that the Colorado River will be depleted well beyond current demands as global temperatures increase, there may be one small bright spot on the horizon. Even if runoff from snow declines, groundwater replenishment in the basin may hold stead under projected increases in precipitation, the U.S. Geological Survey and U.S. Bureau of Reclamation found in a new study.
“You can’t manage what you don’t measure,” said Fred Tillman, lead author and USGS scientist. “These results are the first step in understanding the quantity of groundwater we can expect in the Upper Colorado River Basin; however, further studies are needed to help more accurately forecast future groundwater availability.”
The Colorado River is a critically important source of water for more than 35 million people in the United States and 3 million people in Mexico. As much as half the water flowing in the rivers and streams in the Upper Colorado River Basin originates as groundwater. Understanding how much groundwater is available and how it’s replenished is important to sustainably manage both groundwater and surface water supplies in the Colorado River basin now and in the future.
In the new study, USGS and Reclamation scientists estimated projected changes in groundwater recharge for the Upper Colorado River Basin from recent historical (1950–2015) through future (2016–2099) time periods using climate projections and a groundwater-recharge model.
Simulated future groundwater recharge through 2099 is generally expected to be somewhat greater than the historical average in most decades due to an anticipated wetter future climate in the basin under the most advanced climate modeling projections. Groundwater resources are replenished through increases in precipitation, which may offset reductions from increased temperatures. The full report is available online in the journal Geophysical Research Letters.
But researchers urged caution interpreting the results because a few of the models suggested decreased future recharge relative to the historical climate period.
New growth in delta could offset CO2 released from riverbed
Human management of natural ecosystems always has unintended consequences, and the Colorado River is no exception. After decades of intense dam building and diversions, the mighty river is a mere shadow of it former self, reduced to a trickle in some places and polluted by return flows in others. Along its entire length, ecosystems, including riparian zones and native fish, have suffered, with some of the biggest impacts in the Colorado River delta.
In an effort to restore at least some key reaches of the river, scientists and water managers have teamed up to try mimic some of the Colorado’s natural functions, with controlled releases of water to build up beaches. Those efforts culminated in early 2014 during an eight-week experiment that unleashed a mighty torrent of water from Morelos dam (on the border with Mexico and the USA).
The huge surge (130 million cubic metres) of water raised river levels down to the delta, which has been starved of water for decades. Scientists closely monitored how the release — and potential future releases — affect agricultural crops and natural plant and animal life of the lower delta.
New study helps resource managers plan for climate change
Resource managers grappling with the vexing question of how to allocate Colorado River water to the thirsty cities, ranches and farms of the Southwest have some new food for thought. A new U.S. Geological Survey study published this week in the journal Water Resources Research shows that more than half the streamflow in Upper Colorado River Basin originates as groundwater.