Water: The Essence of Life
| Polish version is here |
The following article was originally published in the quarterly Ekologia (3/2024):
Supportings Biodiversity and Preventing Drought
Amid accelerating climate change, water, in Poland and around the world, has again become a strategic resource, every bit as valuable as energy commodities. Its availability now swings more widely than ever, from spring floods to summer droughts. Both natural and human‑made retention can soften these extremes, buffering ecosystems and economy alike.
Climate change has turned extreme events into the new normal. Torrential downpours followed by long dry spells create a hydrologically unstable landscape where short‑term weather and long‑term water trends are difficult to predict. We increasingly see fields inundated by swollen rivers in May, then cracked by drought in July. Sometimes spring floods give way to a protracted drought just when vegetation should rebound from winter, with disastrous results. In one area a river can run dry, while a village only a few miles away finds its meadows and basements flooded. These contrasts are no longer rare; they signal a water cycle in serious disarray, especially in areas whose landscapes have been degraded and stripped of natural retention features. Both ecosystems and people, whether in rural or urban areas, experience the effects directly.
Across Poland episodes of agricultural, hydrological, and meteorological drought are now commonplace. The problem is not just a lack of rain; it is also how the landscape handles water. Impervious surfaces, drained wetlands, drainage canals, and channelized rivers all prevent adequate storage. Local reservoirs capable of holding water even for a few days are scarce. Here, both natural and engineered retention emerge as some of the most effective tools for climate‑change adaptation.
What Is Retention?
Water retention is the environment’s ability to hold water, whether briefly in puddles and wetlands, seasonally in soils and vegetation, or for the long term in storage reservoirs. It plays a pivotal role in the water balance by preventing rapid surface runoff.
Practically speaking, precipitation does not rush straight into a river or storm drain but lingers in soil, root systems, and surface depressions. Even small pockets of stored water add up, forming a significant reserve of freshwater.
- Natural retention: peatlands, forests, soils, vegetation, natural floodplains, and undisturbed watercourses
- Anthropogenic retention: dam reservoirs, fishponds, rain gardens, urban detention basins, and permeable or “leaky” drainage systems
Effective water storage hinges on cooperation between these two forms. Humans cannot fully replace nature, but we can draw inspiration from it.
Small‑Scale Retention
Small‑scale retention includes simple, local hydro‑technical and nature‑based measures that improve the water balance on limited areas. Nationally, thousands of such points form a network that meaningfully influences Poland’s overall hydrology.
- farmyard ponds and homestead fishponds
- ditches with controllable culverts
- rain gardens
- wet meadows (sometimes called “micro‑wetlands”)
Well‑structured soil rich in organic matter and the roots of hydrophytic plants can store substantial volumes of water. Each square meter of such soil, wetted with a relatively small amount of water, can tangibly delay drought effects.
Small‑scale retention also shapes the microclimate and boosts biodiversity. Stored water attracts pollinating insects, lowers local air temperature, and creates aquatic habitats. Even a small stream that does not dry up in summer becomes a lifeline for hundreds of species, mostly invertebrates but also vertebrates.
Large‑Scale Retention
Large‑scale retention refers to expansive water‑storage systems that operate across entire river basins. While small‑scale retention works locally, large‑scale solutions modulate river discharge, influence groundwater levels, and guide hydrological processes over vast areas. In Poland, reservoirs with a storage capacity exceeding 5 million cubic meters (≈ 1.3 billion US gal) fall into this category.
Dam reservoirs serve multiple purposes: supplying drinking water, providing flood protection, stabilizing flows during drought, and generating hydroelectric power. Unfortunately, traditional dams can disrupt river continuity, block fish migration, submerge habitats, and alter microclimates.
Modern projects increasingly favor run‑of‑river impoundments instead of high dams. These allow rivers to function more naturally while still expanding storage during high‑flow events.
Planning large‑scale retention must balance economic and flood‑defense goals with biodiversity conservation, water quality, social needs, and long‑term climate trends. The key is synergy between infrastructure and nature. Thoughtfully engineered works can coexist with river restoration and floodplain rehabilitation.
Keys to Boosting Biodiversity
Retention at any scale profoundly shapes ecosystems by creating and sustaining habitats that would otherwise degrade. Wetlands are biodiversity hotspots, supporting birds, amphibians, invertebrates, and countless plant species. Their decline is a major driver of population loss among protected species in Poland and across Europe.
These habitats flourish when retention is properly planned. Marshes, oxbow lakes, inundation zones, and shallow retention ponds attract bitterns, herons, geese, storks, and many other birds. Amphibians such as fire‑bellied toads, newts, and common toads require at least seasonally flooded areas for breeding. Crucial to these organisms is not only open water but also the surrounding mosaic of reed beds, meadows, scrub, and vegetated banks.
Slow‑flowing rivers are equally vital. Naturally meandering channels with oxbows, islands, and floodplains act as ecological corridors that let species disperse along river valleys, reconnect populations, and maintain genetic exchange, an essential function in landscapes fragmented by roads or intensive agriculture. Wetlands also play an important role in the global carbon cycle.
Retention as a Shield Against Drought
Retention is not just a flood‑management strategy. As agricultural and hydrological droughts intensify, it becomes a cornerstone of adaptation. Its main function during water scarcity is to delay runoff and stabilize baseflows, the minimum flows that keep rivers and streams alive when rainfall fails.
By allowing water to infiltrate deeper soil layers, retention recharges aquifers. During dry spells these groundwater reserves determine whether vegetation survives. Holding rain where it falls, even for a few hours or days, can transform local conditions, enhance crop resilience, and provide steadier habitats for wildlife.
In agriculture the benefits are immense. Municipalities that have introduced small‑scale retention programs report smaller yield fluctuations, greater drought tolerance, and lower irrigation costs. Locally stored water makes on‑farm irrigation cheaper, greener, and less vulnerable to seasonal anomalies, while allowing more flexible crop rotation and sustainable land use.
From a water‑supply perspective, retention systems stabilize pressure in distribution networks, reduce reliance on deep aquifers, and help maintain levels in dug and drilled wells, a vital service in rural areas where private wells are often the only water source.
Retention also offers educational and social value. Local ponds, rain gardens, and wetland nature trails let people connect with the environment, foster stewardship of water resources, and show that everyone influences the hydrological balance of their landscape.
A Few Case Studies
Real‑world examples confirm the theory. A standout case is the restoration of the Biebrza Valley. Reversing drainage, reinstating river meanders, and recreating former floodplains boosted biodiversity and improved the local microclimate. Now protected within Biebrza National Park, the valley is one of Central Europe’s premier wetland bird habitats.
Another success is the nationwide “Stop the Drought” program run by Państwowe Gospodarstwo Wodne Wody Polskie (Polish Waters). Aimed at enhancing retention locally and regionally, the program also tracks effectiveness and provides analytical tools to support municipal water management.
Internationally, the Dutch “Room for the River” initiative combines flood safety with ecological gains such as rebounding bird populations, improved water quality, and expanded nature‑based tourism.
Equally ambitious is China’s “Sponge City” program, which turns urban areas into water‑absorbing systems: vegetated roofs, permeable pavements, rain gardens, and canal networks retain, store, and reuse rainwater on‑site. The approach mitigates storms and droughts, enhances residents’ quality of life, and supports greener urban development.
Domestic and international cases alike show that well‑planned retention measures yield tangible ecological and economic dividends.
Shared Benefits
When designed with ecological and community needs in mind, water retention delivers broad rewards. Beneficiaries include not only individual species or farmers but also entire ecosystems, societies, and economies.
Ecological benefits
- expansion of natural habitats and restoration of hydrological processes
- improved water quality through natural filtration in wetlands and oxbows
- support for threatened species dependent on periodic inundation and wetlands
- reduced soil erosion and increased organic matter in agricultural landscapes
Social benefits
- enhanced recreational appeal of retention areas
- cooler microclimates that improve urban comfort
- greater environmental awareness through education and community engagement
- stronger social cohesion through projects such as rain‑garden installations, planting events, and river restoration
Economic benefits
- lower costs of drought and flood damage remediation
- steadier yields and decreased irrigation expenses for farmers
- reduced spending on gray storm‑water infrastructure thanks to green technologies
- growth in nature‑based tourism and businesses tied to ecosystem services
All these advantages have a common denominator: they strengthen the resilience of ecological and socio‑economic systems to climate change. Retention is no longer just a hydrological concept; it is a symbol of rational, long‑term natural‑resource management.
Conclusion
Retention is not the exclusive domain of hydrologists and ecologists; it affects farmers, urban planners, teachers, policymakers, and citizens alike. Water held in the landscape is more than insurance against drought and flood. It underpins sustainable development, social well‑being, and biodiversity conservation.
Given the increasingly evident impacts of climate change, systemic water management is imperative. We should invest in river restoration and urban green infrastructure, educate the public, support innovative local solutions, and weave retention into spatial and agricultural policy. Every liter of water (≈ 0.26 US gal) kept where the rain falls is a step toward a resilient ecosystem and a safer tomorrow.
All photographs and illustrations were created by the author.
Marek Ples