The Journey to Nature Positive: Integrating Freshwater Ecological Solutions in Infrastructure.

This is the second article in our The Journey to Nature Positive series, where our experts illustrate how Nature-based Solutions (NbS) can tackle societal challenges, offer additional benefits over engineered solutions, and promote a Nature-positive world. For a refresher on what we mean by Nature-based Solutions; our first article of the series is available to view here.

Today, we are exploring Natural Capital of Freshwater Ecosystems and the benefits nature-positive aquatic ecological solutions can bring to your projects.

The importance of the environment for global economic productivity and societal wellbeing is increasingly being recognised, as are the economic and social benefits of enhancing natural capital at the business and project scales. This was recently recognised through the World Economic Forum 2025 Global Risks Report (1), with biodiversity loss and extreme weather events found to be the greatest long-term threat to the global economy.

Exploring Natural Capital in Freshwater Ecology

With respect to freshwater ecology, natural capital includes but is not limited to:

• The natural flow regime of waterways, including natural patterns of longitudinal and lateral hydrological connectivity, the natural wetting and drying regime of wetlands, and groundwater-surface water connections.
• The condition (continuity, density and width) of riparian vegetation and the roles this vegetation has in regulating solar and inorganic material (e.g. sediment, nutrients) inputs to waterways, and enhanced organic material inputs (e.g. leaves and branches) that contribute to instream food webs and habitat.
• The stability and morphology of stream banks, and diversity of sediment sizes along the bed of waterways, that support the physical habitat features of waterways.
• Threatened freshwater species, including various species of turtle, fish, amphibian and aquatic mammal that are known to have declining or imperilled populations.
• The diversity and biomass of native fish in aquatic environments, and the connectedness of their migration pathways along riverine systems, including connections with downstream marine environments, and their value to sustenance, recreational and commercial fisheries.
• The diversity and biomass of other aquatic species, such as aquatic plants, macroinvertebrates and macroinvertebrates that provide key ecosystem services (e.g. nutrient processing, protection of water quality, support aquatic food webs).

Water and its role in Nature-based Solutions

Although it is often understood that businesses depend on water for their daily operations, the impact on aquatic ecosystems through groundwater depletion, inadvertent pollution and surface water diversion is often overlooked. Incorporating aquatic NbS through the life cycle of infrastructure projects is becoming increasingly more integral for demonstrating a project’s solid environmental stewardship principles, and provides ancillary benefits such as social license to operate and enhanced operating conditions.

SLR has extensive experience in designing and advising on NbS at both the planning scheme and major project scales. This includes the implementation of freshwater ecology solutions such as:

• Water sensitive urban stormwater systems; providing treatment of water quality (e.g. sediment and nutrients) and regulation of runoff volumes to waterways to reduce flashiness of instream flows from urbanised areas.
• Retention, augmentation or rehabilitation of native riparian vegetation to provide benefits for instream water quality, landscape connectivity and both instream and terrestrial ecology.
• Stabilisation of eroding stream banks to maintain physical structure of the waterway and reduce sedimentation, and reduce sediment loads that are exported to downstream marine environments.
• Provision of adequate fish passage at all new instream infrastructure (e.g. culverts), and remediation of fish passage at existing instream infrastructure. For example, incorporating supplemental design elements that enhance fish passage, such as rock ramps, or removal of redundant infrastructure.
• Protection of threatened species habitat, such as safeguarding threatened turtle nesting banks from predation.

Naturalisation of formally channelised (concrete-lined or piped) waterways, and ecological rehabilitation of historically impacted wetlands are significant nature-positive solutions for aquatic ecology receptors.

NbS can enhance the resilience of vulnerable areas by restoring or creating natural infrastructure, such as riparian vegetation, which provide nutrient and sediment regulation functions and support biodiversity. The resulting socio-economic benefits include job creation, recreation, mental health wellness and sustainable livelihoods.

How we can help

NbS provide a significant opportunity to accelerate sustainable approaches to addressing climate change.

Delivering on this ambition will require specialists (including aquatic ecologists, hydrologists, hydrogeologists, engineers, soil scientists, economists, social scientists, and climate scientists) collaborating to plan, design and implement schemes that work and integrate with primary project outcomes.

Our industry leading specialists offer comprehensive aquatic environmental, ecology, and biodiversity services globally. They can support your organisation with governance and strategy advice, as well as operational project support to incorporate NbS at all stages of infrastructure developments.

To speak with one of our specialists, contact Dr. Ben Cook or Eoin Noble today.

Catch up on the below articles to learn more about the support and solutions our specialists are providing in aquatic environments.

• Proposed Accepted Development Requirement updates for constructing or raising waterway barrier works: what you need to know
• The role of Suitably Qualified Fish Biologists in your Waterway Barrier Works Project
• Aquatic Fauna Management Plan: Keeping our aquatic habitat out of harm’s way throughout the project development phase
• Waterway Barrier Works: Minimising impact to fisheries resources and aquatic biodiversity

References

World Economic Forum 2025. Global Risks Report 2025. Available at: https://reports.weforum.org/docs/WEF_Global_Risks_Report_2025.pdf

Vicarelli M, Sudmeier-Rieux K, Alsadadi A, Shrestha A, Schütze S, Kang M, Leue M, Wasielewski D, Mysiak J. On the cost-effectiveness of Nature-based Solutions for reducing disaster risk. Science of The Total Environment. 2024 Jul 6:174524.

Vujcic M, Tomicevic-Dubljevic J, Grbic M, Lecic-Tosevski D, Vukovic O, Toskovic O. Nature based solution for improving mental health and well-being in urban areas. Environmental research. 2017 Oct 1;158:385-92.