How our miniDOT was swept up in a flood — and survived

logger-story-1The miniDOT logger is a submersible water logger that measures dissolved oxygen and water temperature. Scientists working in aquaculture are familiar with the quality of PME instruments, which range from small loggers to larger monitoring systems. But what they may not be aware of is that PME’s innovative products occasionally become intrepid travelers. A weekend storm in January took one of our miniDOTs on a trip that demonstrated the device’s resilience in an extreme situation.

An unexpected journey

When the rains started on Saturday, Jan. 21, the miniDOT logger was anchored in a research pool, dutifully measuring oxygen and temperature, and storing that data on its internal SD card. As the stream waters rose and the storm intensified on Sunday, the device was ripped from its mooring and swept downstream with the surging debris flow.

When the floodwaters subsided, the search and rescue mission began. On Jan. 31, nine days after the miniDOT’s disappearance, everyone was amazed to find it resting on top of sediment on the side of the stream.

Checking satellite imagery, the logger had traveled 250 meters (820 feet) downstream from the research pool. On its journey down the winding creek, this intrepid miniDOT tumbled down 10-foot waterfalls and was pummeled by rocks, uprooted trees, and the tons of sediment carried by the flood.

logger-story-2Battered but not broken

Upon inspection, the miniDOT’s outer housing — made of tough Delrin plastic — sustained only minor scuffs. It was almost completely intact; the device had lost just one pan head screw and its mesh screen.

Throughout its trials, the miniDOT continued collecting and logging measurements without interruption, as confirmed when the data was retrieved.

If it hadn’t been found, the logger might have continued ticking for many months. With two lithium AA batteries, the miniDOT can continuously log data for 365 days or more, depending on measurement interval.

Your data should be durable

logger-story-3Dissolved oxygen is essential for a healthy aquatic ecosystem. As scientists know, the solubility of oxygen decreases as water temperatures increase. Tough and accurate field instruments like the miniDOT logger are essential for a better understanding of aquatic ecosystems. Such instruments also provide important field data useful in determining how climate may be affecting these systems.

We need science and hard data now more than ever, and that takes instruments in the field that are up to the rigors of nature. The miniDOT logger anecdote illustrates what field scientists demand of instrumentation: reliable products that endure long periods of time — and, sometimes, flash floods.