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Two kilometres south of the US–Canadian border, in Pembina, North Dakota, a stream gauge measures the height of the water surging down the Red River. The instrument, one of about 8,000 maintained by the US Geological Survey (USGS), is a sentinel for communities along the river that experienced devastating floods in 2009, 2010 and 2011. Yet this spring, the USGS announced plans to shut down the Pembina stream gauge — a casualty of the sweeping federal budget cuts known as sequestration.

Implemented on 1 March, sequestration slashes about 5% from the budget of every federal agency and programme until the end of the fiscal year on 30 September, with further cuts expected until the end of 2021 unless Congress intervenes. Scientists in fields from biology to astronomy are bracing themselves for an era of smaller and fewer research grants, which will begin within months (see Nature 494, 158–159; 2013). But the cuts are already hampering Earth-monitoring projects, including stream gauges and snowpack measurements, which require a constant influx of funds to keep data flowing.

Monitoring equipment frequently breaks and must be repaired or replaced, usually during the short period of summer fieldwork. That often requires expensive journeys to remote sites by helicopter or other means.

Such is the case for surveys of the United States’ western snowpack, a crucial source of water in summer for many states. Continuing a tradition that began in 1906, when a University of Nevada researcher measured snow depth along a transect in the Sierra Nevada mountains, the US Department of Agriculture’s Natural Resources Conservation Service conducts more than 1,100 manual ‘snow courses’ once a month throughout winter and spring. In 1980 it also began operating automated snow tele­metry (SNOTEL) sites, and it now has around 860 spread over 13 western states. Survey data are used to produce water-supply forecasts and to analyse changes in the snowpack over time.

But in January, the snow survey ann­ounced that it would eliminate 39 snow courses in Montana. The programme was already suffering from reduced funding: it received US$9.3 million in fiscal year 2012, about 15% less than the year before. Congress has not yet finalized the 2013 budget, but the survey is probably facing another 7.5% cut this year when sequestration is taken into account, says Michael Strobel, director of the National Water and Climate Center in Portland, Oregon.

More snow courses may be at risk. “We’re trying to prioritize sites that have scientifically critical information”, says Strobel, as well as to decide “which ones have enough SNOTEL and other sites nearby to have a lower priority”.

SNOTEL sites typically need to be visited each year to have melted snow drained away, antifreeze added and damage from grizzly bears and other problems repaired. But tight budgets will probably prevent workers from getting to every location this summer, so some of the measurements are likely to fail.

Once snow melts and starts running down from the mountains, USGS stream gauges measure it — unless they, too, are shut down. The national stream-gauge network costs about $165 million to operate each year. The federal government supplies a little more than half of that, and state, local and tribal agencies make up the rest. Information from the 8,000 gauges is posted online in real time and used in everything from weather forecasting to designing bridges and planning kayaking trips.

Federal cutbacks mean that about 50 stream gauges are being shut down and some 100 more could be at risk, says Michael Norris, coordinator for the National Streamflow Information Program, based in Reston, Virginia. The USGS prioritizes gauges mandated by law, such as those that support water treaties, as well as gauges in crucial flood-forecast areas or those that have been in operation for a long time. The agency consults with local officials about which gauges can be cut.

The Pembina gauge was targeted because another station just across the Canadian border in Emerson provides much the same information, says Gregg Wiche, head of the North Dakota Water Science Center in Bismarck. But when Wiche heard how much the community used the information — a local railway relies on its forecasts, for example — he and others worked out a deal to keep the Pembina station and drop one elsewhere in the state instead.

Such small adjustments do little to reassure Johnnie Moore, a hydrologist at the University of Montana in Missoula who has used USGS streamflow data to study long-term trends in melt run-off from the northern Rocky Mountains. He worries that shutting off stream gauges that have been operating for decades could hurt climate-change studies. “Over the long run there’s been a big decline in the number of gauges”, says Moore, and to cut even more now “is pretty disconcerting”.

The outlook is not entirely grim: some of the 50 or so gauges at immediate risk have received extra funding from state or local governments to carry them through to 30 September.

And US President Barack Obama’s budget request for fiscal year 2014 asks for a 25% increase over 2012 levels for the streamflow information programme. That money, if Congress provides it, could let the USGS go back to watching the west’s water.