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Ditches are all around: along roads, through neighborhoods, across fields and marshes. These human-made waterways are so common that they can be easy to miss. A new literature review in Communications Earth & Environment calls on the public to pay more attention to this often neglected resource, one that could advance sustainability goals and benefit local communities with modern ditch management strategies.

In the English language, "ditch" has a bad rap. It evokes images of trash or something that ought to be discarded. That negative connotation and the everywhereness of ditches helps explain why they've been understudied and undervalued, according to the authors of the "Lines in the Landscape" article.

This paper was produced by a collective of self-described "ditchologists," whose informal talks at conferences and over email eventually culminated in a series of Zoom meetups that led to a more organized research effort.

"As that group was established and grew, it became apparent that us ditchologists aren't perhaps quite as rare as we thought," said co-lead author Michael Peacock of the University of Liverpool. "And so we had the idea to try and get funding to arrange a hybrid meeting to bring forward different views and research backgrounds, and learn from each other what we think ditches 'do,' and why they matter to us all."

The dozens of authors involved looked at ditches as waterways from multiple angles: their social and economic aspects, physical and chemical characteristics and the plants and animals which inhabit these ecosystems.

"Ditches aren't actually boring," said co-lead author Chelsea Clifford, a former research scientist at William & Mary's Batten School of Coastal & Marine Sciences & VIMS. "Try taking a closer look at yours."

The overlooked history of ditches

Ditches are a staple of human history, with archaeologists dating them as far back as 8,000 years ago. They have been built on every continent, even Antarctica. Loosely defined by the paper as "linear constructions which store and/or move water where humans prefer it to go," these channels can provide irrigation, drainage, power and more.

On the other hand, ditches can also cause harm and environmental damage, like spreading pollutants, proliferating invasive species and emitting greenhouse gases.

Regulations could help ensure that ditches benefit people and their environments more than harm them, but the paper points out that legislation, including the U.S. Clean Water Act, doesn't directly address them. That omission, the authors argue, has consequences.

"When this lack of regulation is combined with their capacity to carry harmful pollutants and pathogens, whose load is typically elevated, often deliberately concentrated, in areas of high poverty," the paper reads, "then artificial channels [like ditches] become hotspots for environmental injustice and exploitation."

Innovations in ditch management

At the same time, the absence of extensive oversight provides an opportunity to experiment and innovate. In the study and maintenance of ditches, there are many areas where creative thinking is needed, such as figuring out how to plot where ditches are.

"Not only do we usually not have very good maps of them," Clifford said, "recent updates of maps of waters in general have sometimes cut them out."

Paper co-authors, however, have made progress in charting the vast global network of ditches using the latest technology.

"Technology has advanced from the object-based image analysis methods we used in our to the modern-day machine learning and artificial intelligence methods used in our ," said co-author John Connolly of Trinity College Dublin. "My interest in mapping these lines in the landscape and considering their impact on society in general and peatlands in specific has increased—especially since finding our community of ditchologists."

Ditches can host unique ecosystems, featuring fish, amphibians, and waterbirds, as well as rare species like the fen ragwort flower or ram's-horn snails, adding to local biodiversity.

But similar to other aquatic ecosystems, ditches can also bear high nutrient loads and take on runoff, including various pollutants like pesticides, trace metals and microplastics. Fortunately, this tendency could be leveraged to better mitigate pollution with appropriate ditch management strategies. Moreover, because ditches are often part of larger waterway networks, they can make it possible to spot water quality issues before they flow downstream.

Clifford said that this predictive property of ditches extends to anticipating sea level rise and its ramifications. "They can be sentinels of what's to come before the surrounding landscape also changes to marsh, and then to open water," she said.

The potential environmental benefits of ditches

This literature review is a major step toward bringing ditches out of obscurity as a subject of study, and the authors shine light on possible paths for future research and practice. Even though the number of ditch-centric regulations is slim, there are guiding documents that could assist in crafting legislation like the European Union's Water Framework Directive, which advises on "heavily modified and artificial waterbodies."

Part of the challenge with bringing ditches to their full potential as waterways is that their complexity demands multidisciplinary study and coordinated ditch management. While difficult, such synergies are possible if ditches are seen at the landscape scale, as "ditchscapes."

Ultimately, ditches can be a source of optimism about environmental conservation and restoration, said Clifford.

"If we're smart and brave and take initiative about what could be," Clifford said, "and start trying to manage ditches as corridors to the future rather than just relicts of mistakes of the past, they could become symbols of hope too."