Hurricane Helene struck North Carolina in September 2024 and caused over $59.6 billion in total damage: including damage to more than 160 water and sewer systems that left hundreds of thousands of people without running water for weeks [1][2]. In Jackson, Mississippi, historic flooding had already damaged a water treatment plant so severely that over 150,000 residents lost safe drinking water [3]. These are not rare exceptions. They are the new normal conditions.
The IPCC Sixth Assessment Report (AR6) states it plainly: water cycle variability and extremes are projected to intensify regardless of mitigation policy [4]. Infrastructure designed under the assumption of a stable climate (which describes virtually every water intake built before 2020) is systematically underestimating the conditions it will face over its 25–100 year service life.
This article examines how climate change affects water intake infrastructure specifically, what makes an intake resilient, and how passive, structurally robust technologies like Coanda screens counter climate risks that conventional mechanical systems cannot.
Table of Contents
- The Climate Threat to Water Intake Infrastructure
- Five Climate Hazards That Affect Water Intakes
- What "Climate-Resilient" Really Means for Intakes
- Why Conventional Intake Systems Fail Under Extreme Climate Conditions
- How Passive Intake Technology Builds Resilience
- Designing for Drought: Low-Flow Adaptation
- Designing for Flood: High-Flow Survival
- Designing for Extreme Cold: Frazil Ice and Anti-Icing
- Designing for Heat: Elevated Temperature and Water Chemistry Shifts
- The Economics of Climate-Resilient Intake Design
- ADENCO's Climate-Resilient Design Approach
- Frequently Asked Questions
- References
The Climate Threat to Water Intake Infrastructure
Water infrastructure has traditionally been designed using historical hydrological data: flood recurrence intervals, seasonal flow patterns, temperature ranges, and sediment loads observed over the past 50–100 years. Engineers selected design parameters based on the implicit assumption that the future would resemble the past [5][6].
That assumption is no longer valid.
The IPCC AR6 documents that anthropogenic climate change has already increased atmospheric moisture and precipitation intensity, increased terrestrial evapotranspiration, and contributed to drying in Mediterranean, southwestern Australian, and western North American climates [4]. These are not projections. They are observed changes.
For water intake infrastructure, this means five specific hazards: each of which can cause intake failure, supply disruption, or accelerated asset deterioration.
Five Climate Hazards That Affect Water Intakes
1. Drought and Low Flow
Prolonged drought reduces river and reservoir levels, potentially leaving intakes designed for historical minimum water levels above the water line. When water levels drop below the intake elevation, supply stops entirely. Even before that threshold, reduced flow concentrates dissolved minerals and contaminants: chloride, turbidity, and organic load all increase during low-flow events [7].
Between 2020 and 2025, drought-related water supply disruptions have affected communities across the western United States, southern Europe, East Africa, and Australia. The U.S. Drought Monitor has documented increasingly frequent and prolonged drought conditions that put pressure on water utility operations [7].
2. Extreme Precipitation and Flooding
Intense rainfall events (increasing in both frequency and magnitude) cause rapid river rise, extreme debris loads, and turbidity spikes that can overwhelm intake systems in hours. Flood flows carry logs, branches, plastic, and sediment loads many times higher than normal conditions [3].
Intake structures located in floodplains or adjacent to rivers are particularly vulnerable. Flood debris can physically damage screens and supporting structures, while extreme turbidity loads can clog fine filtration systems and force treatment plants to shut down.
3. Frazil Ice and Extreme Cold
Supercooling events (where water temperature drops just 0.01–0.1°C below 0°C) trigger the formation of frazil ice (small ice crystals carried in flowing water). These microscopic ice crystals adhere to any submerged surface, including intake screens, and can block water flow within hours [8][9]. The Salem Nuclear Plant (2010) and Point Beach Nuclear Plant (2000) both experienced forced shutdowns from frazil ice clogging of their intake systems.
Climate models suggest that while average winter temperatures are rising, the frequency of extreme cold events (polar vortex events, rapid temperature drops) may increase in some regions due to disrupted atmospheric circulation patterns [8]. The question is not whether average winters are warmer. It is whether the worst single night of the winter is cold enough to trigger supercooling.
4. Elevated Water Temperature
Warmer water accelerates corrosion, promotes biological fouling (algae, biofilm, freshwater mussels), and changes the solubility of dissolved minerals. For stainless steel intake screens, elevated temperature directly reduces the Critical Pitting Temperature (CPT) margin: the safety buffer between operating conditions and corrosion onset [10].
A screen designed for 20°C average water temperature with a grade selected at the chloride threshold may begin pitting at 30°C peak summer temperature if the grade was not selected with adequate safety margin.
5. Sediment Regime Changes
Glacial melt, wildfire, and land-use change alter the sediment load in rivers. Post-wildfire catchments can deliver sediment concentrations 10–100 times higher than normal for years after the fire. Glacial retreat exposes new sediment sources. Urbanisation increases runoff from impervious surfaces and peak sediment delivery during storms.
These changes mean that a screen designed for historical sediment conditions may face significantly higher loads than anticipated: reducing effective flow capacity and increasing maintenance requirements.
What "Climate-Resilient" Really Means for Intakes
Climate resilience is not a specification number. It is a design philosophy that answers three questions:
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Can the intake survive the event? A flood, ice storm, or drought that physically damages or disables the intake structure is a catastrophic failure. Survival means the structure remains intact and functional after the event passes.
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Can the intake operate during the event? Maintaining water supply during a drought, flood, or ice event (even at reduced capacity) is fundamentally different from shutting down and restarting afterward. Continuous operation is the highest resilience standard.
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Can the intake recover without external intervention? An intake that requires a maintenance crew to remove debris, de-ice, or reset equipment after every extreme event has limited resilience. An intake that self-recovers (returning to normal operation as conditions normalize) is truly resilient.
The World Bank's Lifelines report quantified the economics: making infrastructure more climate-resilient adds approximately 3% to the initial capital cost but delivers a 4:1 benefit-to-cost ratio: $4 saved in avoided damage and disruption for every $1 invested in resilience [11]. For water intake infrastructure specifically, the return is often higher because supply disruption affects public health, industrial production, and agricultural output simultaneously.
Why Conventional Intake Systems Fail Under Extreme Climate Conditions
Conventional mechanical intake screens (travelling band screens, mechanically raked bar screens, powered drum screens) are designed for normal operating conditions with maintenance support. Under extreme climate conditions, their vulnerabilities become critical:
Dependence on electricity. Mechanical screens require electricity. Flood events and ice storms frequently cause power outages. When the grid fails, the screen fails. Backup generators solve this only partially, but add complexity, cost, and another failure point.
Mechanical vulnerability. Moving parts (chains, sprockets, bearings, motors, spray nozzles) are damaged by flood debris impact, jammed by ice formation, and degraded by sediment abrasion. A travelling band screen struck by heavy flood debris can be put out of action by a single event.
Narrow operating range. Mechanical screens are designed for a specific flow range. They perform well within that range and poorly outside it. Drought flow far below design minimum causes the screen to operate dry (damaging seals and bearings). Flood flow far above design maximum overloads the raking mechanism and can submerge the entire structure.
Maintenance dependency. After every significant weather event, mechanical screens typically require inspection, debris removal, and potentially repair before returning to normal operation. This requires trained staff accessing the site: which may be inaccessible during or immediately after the event.
These are not hypothetical failures. They are documented failure modes that have caused real supply disruptions during real climate events.
How Passive Intake Technology Builds Resilience
Coanda screens are passive, static, gravity-driven structures with no electricity supply, no moving parts, and no mechanical systems [12][13]. This basic design directly counters each of the vulnerabilities that make conventional systems fail under extreme climate conditions:
| Climate Hazard | Conventional Screen Vulnerability | Coanda Screen Response |
|---|---|---|
| Power outage | Screen stops (no filtration) | Unaffected: gravity-driven, no electricity required |
| Flood debris impact | Mechanical components damaged | Static stainless steel structure: no moving parts to damage |
| Extreme debris load | Raking mechanism overwhelmed | Self-cleaning: debris swept off continuously by flow |
| Ice formation | Ice jams moving components | No moving parts to jam; anti-icing options available |
| Drought / low flow | Operates dry: seal and bearing damage | Operates at reduced capacity; no damage at low flow |
| Post-event recovery | Manual debris removal, inspection, potential repair | Self-recovering: resumes normal operation when flow normalises |
| Sediment surge | Abrades mechanical components | Static wedge wire: no moving parts to abrade |
This does not mean Coanda screens are immune to climate impacts: no technology is. But their failure modes are fundamentally different from mechanical systems. A Coanda screen under extreme conditions may deliver reduced capacity. A mechanical screen under the same conditions may stop operating entirely.
Designing for Drought: Low-Flow Adaptation
Drought reduces the water volume available to flow over a Coanda screen's acceleration plate. Below a minimum flow threshold, the self-cleaning mechanism becomes less effective and some debris may accumulate on the lower screen area. However:
- The screen does not suffer mechanical damage at low flow (no dry-running seals, no bearing wear)
- Screened water continues to pass through the upper portion of the panel
- When flow increases, accumulated debris is flushed off automatically
Climate-resilient design measures for drought:
- Oversizing by 1.5–2.0× the present design flow to maintain adequate self-cleaning velocity even as flows decline. The extra cost of additional screen width is far less than the cost of a supply interruption.
- Multi-panel arrays where individual panels can be isolated if flow drops below the minimum for the full array: concentrating available flow across fewer panels to maintain effective self-cleaning.
- Lower weir crest elevation to take in water at reduced river levels: designed using climate-adjusted flow projections rather than historical minimums.
- Material selection with temperature margin: selecting stainless steel grades with Critical Pitting Temperature (CPT) values well above historical maximum water temperature, anticipating that drought often coincides with higher water temperature and concentrated chloride.
Designing for Flood: High-Flow Survival
Flood events test whether the intake structure survives physical loads from debris, high-velocity flow, and potential submersion. For Coanda screens, flood resilience is primarily a structural and civil engineering challenge:
Climate-resilient design measures for flood:
- Hydrodynamic frame profiles that deflect flood debris rather than trapping it. ADENCO designs screen frames with curved leading edges and tapered profiles that allow debris to pass over the structure during overtopping events.
- Anchor systems designed for flood recurrence intervals: not historical 100-year events, but climate-adjusted intervals that account for increasing flood frequency and magnitude.
- Bypass channels that divert excess flood flow around the screen structure, preventing high-velocity flow from striking the screen panel directly.
- Elevated control structures that protect downstream collection chambers and penstock connections from flood inundation.
- No electrical or mechanical components that could be damaged by flood immersion, because the screen has none to begin with.
After a flood event, a Coanda screen requires only visual inspection to confirm structural integrity. There are no motors to dry out, no chains to unblock, no bearings to re-lubricate. If the structure is intact, it is operational.
Designing for Extreme Cold: Frazil Ice and Anti-Icing
Climate change does not eliminate cold extremes: it may intensify them in some regions through polar vortex disruption. Research at NTNU (Norwegian University of Science and Technology) documented two ice clogging mechanisms specific to Coanda screens [14]:
- Type I: Soft ice adhering to wire surfaces at moderate sub-zero temperatures: manageable with adequate flow
- Type II: Solid ice forming between wires at extreme temperatures (below -14°C): requires active intervention
Climate-resilient design measures for extreme cold:
- Electric heating elements integrated into the screen frame: activated automatically when water temperature approaches 0°C
- Warm water recirculation using waste heat from the downstream facility (treatment plant, powerhouse, or industrial process)
- Heated air diffuser systems positioned below the screen to prevent supercooling in the approach flow
- Low-carbon stainless steel grades (304L / 316L) for screens with electric heating, resisting sensitisation from thermal cycling
- Insulated enclosures for critical sites where heating alone may be insufficient
For a comprehensive discussion of anti-icing technologies and frazil ice physics, see: Anti-Icing Technology for Water Intake Screens.
Designing for Heat: Elevated Temperature and Water Chemistry Shifts
Warmer water temperatures (both average and peak) affect intake screens through three mechanisms:
Accelerated corrosion. Every 10°C increase in water temperature roughly halves the safe chloride limit for a given stainless steel grade [10]. A screen designed for 20°C water temperature and 200 ppm chloride (safe for 304L) may face pitting at 35°C summer temperature if climate-driven warming shifts the peak temperature above historical values.
Biological fouling. Warmer water promotes algae growth, biofilm formation, and freshwater mussel colonisation on screen surfaces. While Coanda screens' self-cleaning action reduces this during operation, extended low-flow periods combined with warm water may accelerate fouling.
Dissolved mineral concentration. Drought and heat together reduce dilution and increase evaporative concentration of dissolved minerals: including chloride. A river that historically measured 100 ppm chloride may reach 300 ppm during a combined drought-heat event, crossing the threshold at which 316L is required instead of 304L.
Climate-resilient design measures for heat:
- Material grade with temperature margin: selecting 316L where 304L would suffice under present conditions, anticipating that future peak temperatures and chloride concentrations may shift beyond historical ranges
- Material selection based on the Pitting Resistance Equivalent Number (PREN) using climate-adjusted water chemistry projections, not just present-day measurements
- Increased inspection frequency during heat events to monitor for early signs of biological fouling or corrosion
For detailed material selection guidance, see: 304 vs. 316 Stainless Steel for Water Intake Screens.
The Economics of Climate-Resilient Intake Design
The economic argument for climate-resilient intake infrastructure is clear:
The cost of failure is catastrophic. Hurricane Helene's $59.6 billion in damage to North Carolina (including over 160 damaged water systems) demonstrates the scale of loss from climate-unprepared infrastructure [1][2]. The EPA allocated $337 million in emergency water infrastructure funding for North Carolina alone [2].
The cost of resilience is small. The World Bank finds that making infrastructure climate-resilient adds approximately 3% to the initial capital cost [11]. For a water intake costing $50,000, the resilience premium is approximately $1,500: oversizing the screen, selecting a higher material grade, and adding anti-icing measures.
The return is 4:1 or higher. Every $1 invested in climate-resilient infrastructure saves $4 in avoided damage, repair, and disruption [11]. For water intakes specifically, the avoided costs include emergency repair, temporary water supply, lost production or revenue, regulatory penalties, and public health interventions.
Passive systems increase the savings further. A Coanda screen that requires no electricity, no moving parts, and no mechanical maintenance is inherently cheaper to operate than a mechanical screen in normal conditions. Under extreme climate conditions, this cost advantage multiplies: because the mechanical screen requires emergency repair, replacement parts, and recovery labour while the passive screen continues operating or self-recovers.
The question is not whether climate-resilient intake design is economically justified. It is whether the alternative (infrastructure designed for a climate that no longer exists) can be justified.
ADENCO's Climate-Resilient Design Approach
Every ADENCO Coanda screen is designed for the specific conditions at its site. For climate resilience, we extend that site-specific approach in four areas:
1. Climate-adjusted hydrology. We size screens using projected flow ranges: not just historical data. This means larger screen widths (1.5–2.0× the present design flow) to maintain performance under drought conditions and structural design for climate-adjusted flood intensities.
2. Material selection with safety margin. We select stainless steel grades based on worst-case water chemistry projections: anticipating higher peak temperatures, lower flows, and concentrated mineral content. When conditions approach a grade boundary, we select the next grade up rather than operating at the threshold.
3. Anti-icing readiness. For sites in climate zones where extreme cold events are possible (even if rare) we design screen frames so that anti-icing equipment can be retrofitted later. This means mounting points, wiring conduits, and structural capacity for heating elements can be added without replacing the screen.
4. Structural resilience. Frame profiles, anchor systems, and civil works are designed for climate-adjusted flood loads: not historical recurrence intervals. The cost of a stronger anchor is negligible. The cost of a screen washed downstream in a flood is not.
This approach adds a small premium to the initial cost and delivers a full design life of reliable operation across conditions that will increasingly deviate from historical norms. It is not precautionary speculation. It is engineering for the climate we already have.
Frequently Asked Questions
How does climate change affect water intake infrastructure?
Climate change affects water intakes through five primary hazards: drought (reduced water levels and flow), extreme precipitation and flooding (debris surges, structural damage), frazil ice from extreme cold events, elevated water temperature (accelerated corrosion, biological fouling), and sediment regime changes (post-wildfire, glacial melt). The IPCC AR6 confirms that water cycle variability and extremes are intensifying regardless of mitigation efforts. Infrastructure designed for historical climate conditions is increasingly mismatched with real operating conditions.
What makes a water intake "climate-resilient"?
A climate-resilient intake meets three criteria: it survives extreme events without structural failure, it operates during events (even at reduced capacity) rather than shutting down, and it self-recovers without manual intervention when conditions normalise. Passive technologies like Coanda screens are inherently more resilient than mechanical systems because they have no dependence on electricity, no moving parts to damage or jam, and gravity-driven self-cleaning that continues operating through debris surges and flow extremes.
Is climate-resilient infrastructure more expensive?
The World Bank estimates that climate-resilient design adds approximately 3% to the initial capital cost, but delivers a 4:1 return on investment through avoided damage and disruption. For a typical water intake, the resilience premium covers oversizing the screen for drought, selecting a higher stainless steel grade for temperature margin, and adding anti-icing measures. This extra cost is far less than a single emergency repair after a climate event damages a conventional intake.
How do you design a water intake for drought?
Drought-resilient intake design involves oversizing the screen width by 1.5–2.0× the present design flow (to maintain self-cleaning at reduced flows), using multi-panel arrays with isolation capability, lowering the weir crest elevation based on climate-adjusted flow projections, and selecting stainless steel grades with corrosion margin for the higher temperatures and concentrated chloride that typically accompany drought conditions.
Can Coanda screens survive flood events?
Yes, with appropriate structural design. Coanda screens have no moving parts, motors, or electrical components that can be damaged by flood immersion. ADENCO designs screen frames with hydrodynamic profiles that deflect flood debris, anchor systems rated for climate-adjusted flood loads, and bypass channels to divert excess flow. After a flood, a Coanda screen requires only visual inspection: there are no mechanical components to dry out, clear, or replace.
What is the IPCC saying about water infrastructure and climate?
The IPCC AR6 Working Group II, Chapter 4 (Water) documents that climate change has already increased precipitation intensity, shifted seasonal flow patterns, and intensified drought in many regions. It projects that these trends will continue and accelerate. The report specifically identifies water infrastructure designed on the assumption of an unchanging climate as increasingly vulnerable to failure. Adaptation through resilient design (using updated climate projections rather than historical data) is identified as a critical priority.
References
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"EPA Announces $337 Million to North Carolina for Water Infrastructure Resiliency and Repair." U.S. EPA, 2024. Retrieved April 2026, from https://www.epa.gov/newsreleases/epa-announces-total-337-million-north-carolina-water-infrastructure-resiliency-and
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"US Cities at Risk of Catastrophic Water Infrastructure Failure." CNN, September 2023. Retrieved April 2026, from https://www.cnn.com/2023/09/02/us/water-infrastructure-failure-us-cities-climate/index.html
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IPCC (2022). "Chapter 4: Water." Climate Change 2022: Impacts, Adaptation and Vulnerability (AR6 Working Group II). Retrieved April 2026, from https://www.ipcc.ch/report/ar6/wg2/chapter/chapter-4/
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"Urban Water Infrastructure: Climate Change Impacts and Adaptation Strategies." Urban Climate, ScienceDirect, 2024. Retrieved April 2026, from https://www.sciencedirect.com/science/article/pii/S2212095524003298
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"Drought and Water Utility Impacts." Drought.gov, National Integrated Drought Information System. Retrieved April 2026, from https://www.drought.gov/sectors/water-utilities
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"Prevention of Water Intake Blockage by Ice during Supercooling Events." Journal of Cold Regions Engineering, Vol 37, No 1, ASCE, 2023. Retrieved April 2026, from https://ascelibrary.org/doi/10.1061/JCRGEI.CRENG-676
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"Frazil Ice Intake Challenges: Balancing Environmental Impacts with Plant Operation." Hazen and Sawyer. Retrieved April 2026, from https://www.hazenandsawyer.com/articles/frazil-ice-intake-challenges-balancing-environmental-impacts-with-plant-ope
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"Susceptibility of Type 304/304L and 316/316L Austenitic Stainless Steels to Chlorides in Cooling Water." Digital Refining. Retrieved April 2026, from https://www.digitalrefining.com/article/1002873/
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World Bank / GFDRR (2019). Lifelines: The Resilient Infrastructure Opportunity. Retrieved April 2026, from https://www.worldbank.org/en/news/press-release/2019/06/19/42-trillion-can-be-saved-by-investing-in-more-resilient-infrastructure-new-world-bank-report-finds
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Wahl, T.L. (2003). Design Guidance for Coanda-Effect Screens. U.S. Bureau of Reclamation, Research Report R-2003-03. Denver, CO.
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Wahl, T.L. (2001). "Hydraulic Performance of Coanda-Effect Screens." Journal of Hydraulic Engineering, Vol 127, No 6. ASCE.
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"Performance of Coanda-Effect Screens in a Cold Climate." Journal of Cold Regions Engineering, Vol 28, No 4, ASCE, 2014.
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"Making the Case for Climate-Resilient Water Infrastructure and Supporting Strategies." Water Research Foundation. Retrieved April 2026, from https://www.waterrf.org/research/projects/making-case-climate-resilient-water-infrastructure-and-supporting-strategies
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"Resilient Water Infrastructure Design Brief." World Bank Open Knowledge Repository. Retrieved April 2026, from https://openknowledge.worldbank.org/entities/publication/709788c9-b5e2-5190-8845-b757f33ac7d4
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"Financing the Future of Water: Unlocking Investment, Innovation, and Governance for Resilient Infrastructure." Earth Systems and Environment, Springer, 2025.
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UN-Water (2024). "Analytical Brief on Water for Climate Mitigation." Retrieved April 2026, from https://www.unwater.org/
Published by ADENCO: Advanced Engineering Coanda Intake Screens. ADENCO designs water intake infrastructure for the climate that is coming, not the climate of the past. Every screen is designed with climate-adjusted hydrology, material safety margins, anti-icing readiness, and structural design for flood loads. Request a climate-resilient intake consultation →