A single leaf fibre can clog a snow gun nozzle. A handful of fine sediment can scratch (score) the impeller of a high-pressure pump. And an event of frazil ice (small ice crystals carried in flowing water) can shut down an entire snowmaking system overnight: at the exact moment your resort needs snow the most.
Snowmaking equipment manufacturers like TechnoAlpin and Demaclenko design their snow guns (fan guns) and snow lances with ceramic and ruby nozzle inserts rated for decades of use, but only if the water reaching them is clean. The water intake is the first and most critical point of filtration in any snowmaking system, yet it is the component that receives the least attention in most snowmaking infrastructure designs.
This guide covers every aspect of engineering a water intake for snowmaking: water quality requirements, choice of intake technology, anti-icing solutions and system sizing. It is written from the perspective of a manufacturer that has supplied Coanda intake screens to ski resorts in the most demanding alpine environments.
Table of Contents
- Why Water Quality Matters for Snowmaking
- Snowmaking Water Quality Requirements
- The Snowmaking Water Supply Chain
- Water Intake Technologies for Ski Resorts
- Why Coanda Screens Are Ideal for Snowmaking Intakes
- Anti-Icing: The Critical Challenge
- How to Size a Snowmaking Intake
- Reclaimed Water Snowmaking: The Emerging Trend
- Frequently Asked Questions
- References
Why Water Quality Matters for Snowmaking
Snowmaking is a precision process. Modern snow guns atomize water through nozzles with openings measured in fractions of a millimetre, operating at pressures up to 700 psi (48 bar) [1]. Any particle that reaches these nozzles creates problems:
- Nozzle clogging: Organic debris (needles, leaves, algae) and mineral particles block nozzle openings, reducing snow output and requiring manual clearing during peak production periods.
- Nozzle wear: Abrasive sediment (sand, silt, fine gravel) erodes ceramic and ruby nozzle inserts, degrading atomization quality and snow consistency over time.
- Pump damage: High-pressure snowmaking pumps are precision equipment. Sediment passing through impellers causes surface scratching (scoring), seal wear, and premature failure. Pump rebuilds or replacements are among the most expensive snowmaking maintenance items.
- UV sterilization failure: Many systems include UV treatment for water quality compliance. Turbidity from suspended solids reduces UV transmission effectiveness.
The financial consequences add up: a clogged nozzle on one snow gun means that section of ski run (piste) doesn't receive snow during the production period. With snowmaking systems typically operating only when temperatures are below freezing (often only at night) every hour of lost production directly means less skiable terrain [2].
Snowmaking Water Quality Requirements
Snow equipment manufacturers specify water filtration to 100 microns (0.1 mm) as the minimum standard for protecting high-pressure pumps, snow guns and snow lance nozzles [3][4]. However, this 100-micron specification is for the final filtration stage at the pump house: not for the raw water intake.
The water supply chain for snowmaking involves multiple filtration stages, each serving a different purpose:
| Filtration Stage | Location | Target | Typical Fineness |
|---|---|---|---|
| Primary intake screening | Water body (river, lake, reservoir) | Leaves, branches, gravel, aquatic debris, fish | 0.5–2.0 mm |
| Secondary pre-filtration | Pump house inlet | Fine sediment, organic matter, algae | 200–500 microns |
| Final filtration | Pump house, before distribution | Fine particles, remaining contaminants | 100 microns |
The primary intake screen is the most important stage because it determines the debris load that reaches all downstream equipment. A well-designed intake screen that removes debris down to 0.5–1.0 mm dramatically reduces the burden on downstream filters, extends pump house filter service life, and prevents the chain of problems that begins when contaminated water enters the pressurized system.
Common Contaminants in Snowmaking Raw Water
Snowmaking water is typically taken from mountain streams, rivers, lakes, or purpose-built reservoirs. Each of these presents its own contamination challenges:
| Water Body | Primary Contaminants | Intake Challenge |
|---|---|---|
| Mountain stream | Gravel, sand, silt, leaves, needles, branches, aquatic insects | High sediment during snowmelt and storms; debris surges in autumn |
| Alpine lake / reservoir | Algae, organic silt, leaves, pine/fir needles, aquatic organisms | Seasonal algae blooms; stratification changes; wind-blown debris accumulation |
| River diversion | All of the above plus larger debris, woody material, fish | Higher flow velocities; flood debris; fish protection regulations |
| Reclaimed water | Treated effluent with residual suspended solids | Requires finest screening; regulatory compliance; UV treatment |
Water from dams or reservoirs is particularly challenging because these sources are "often contaminated with fir, spruce and larch needles, leaves and waste" that accumulate in the water stored behind the dam [3].
The Snowmaking Water Supply Chain
Understanding the full water supply chain helps engineers position the intake screen correctly within the system.
Step 1: The Water Body
Water is taken from a permitted water body (a river, lake or reservoir) or from a reclaimed water treatment facility. Water abstraction (withdrawal) permits typically specify maximum withdrawal rates and may impose environmental conditions (minimum residual flow, fish screening requirements).
Step 2: Primary Intake Screening
The intake screen is the first physical barrier between the raw water and the snowmaking infrastructure. It removes debris, sediment, and organic material before water enters the conveyance pipeline. For gravity-fed systems, the intake screen also controls the flow rate based on available head.
Step 3: Conveyance Pipeline
Water is conveyed from the intake to the pump house via pipeline: often over significant distances and elevation changes in mountain terrain. Any debris that passes the intake screen can settle in low points, clog valves, and restrict flow in the pipeline.
Step 4: Pump House
The pump house contains high-pressure pumps, secondary/tertiary filtration, control systems, and often air compressors for snow lances. Water is pressurized to 300–700 psi and distributed through the snowmaking network [1].
Step 5: Distribution and Snowmaking
Pressurized water travels through buried or above-ground pipelines to hydrants along the ski runs, where snow guns or snow lances atomize the water into snow crystals.
Water Intake Technologies for Ski Resorts
Ski resort water intakes face a unique combination of challenges that few other applications share:
- Remote mountain locations with limited or no electricity supply at the intake
- Extreme cold: the intake must function when temperatures are well below freezing, precisely when snowmaking demand is highest
- Seasonal debris variation: autumn leaf fall, spring snowmelt sediment, summer algae
- High-altitude, high-gradient streams with rapid flow changes and sudden surges of debris
- Environmental sensitivity: mountain waterways often have fish protection requirements
These constraints eliminate most conventional intake screen technologies:
| Technology | Electricity Required | Cold Climate Performance | Remote Site Suitability | Fine Screening |
|---|---|---|---|---|
| Trash rack (mechanically raked) | Yes | Good | Poor (needs electricity) | No (20+ mm) |
| Drum screen | Yes | Poor (freeze risk) | Poor (needs electricity) | Yes |
| Travelling band screen | Yes | Poor (freeze risk) | Poor (needs electricity) | Yes |
| Passive wedge wire (submerged) | No | Poor (ice adhesion) | Good | Yes |
| Coanda screen | No | Good (with anti-icing) | Excellent | Yes (0.5 mm) |
Why Coanda Screens Are Ideal for Snowmaking Intakes
Coanda screens solve every challenge of snowmaking water intake simultaneously.
No Electricity Required
Mountain intake sites are frequently located far from electrical infrastructure. Installing power lines to a remote intake can cost more than the intake itself. A Coanda screen operates entirely by gravity: no motors, no pumps, no electrical connection [5][6]. Gravity is the power source: it accelerates the water over the acceleration plate, and the Coanda effect pulls the water through the slots.
Fine Screening in a Single Stage
With slot widths down to 0.5 mm, a Coanda screen removes leaves, needles, insects, gravel, coarse sediment, and organic debris in one stage. A 0.5 mm slot is coarser than the 100-micron specification the pump house applies at final-stage filtration, so the intake screen does not replace those filters: it removes most of the debris before it reaches them, which is what extends the interval between backwashes and cartridge changes [5].
Self-Cleaning Without Intervention
In autumn, when deciduous trees shed leaves into mountain streams, debris loads can rise sharply. Conventional intake screens clog within hours, requiring manual cleaning at remote, often difficult-to-access sites. Coanda screens self-clean continuously: the curved screen geometry and flow velocity carry debris off the screen face and into the bypass channel [5][6]. Clogging does not build up.
Compact and Low in Height
Mountain intake sites often have limited space: steep banks, narrow river channels, constrained access. Coanda screens are mounted directly on the weir crest in a compact, low-height arrangement. For example, a 0.75 m ADENCO-70 unit is rated 50 l/s (see the products page).
Fish and Environmental Protection
Mountain streams are frequently habitat for trout, salmon, and other sensitive species. Coanda screens with 1.0 mm slots provide complete fish exclusion without suction and without pressing fish against the screen (impingement), and can be supplied to meet fish screening requirements in the EU, UK, and North America [7][8]. Research has confirmed that salmon smolt and fry (newly hatched fish) pass over Coanda screens undamaged [9].
Anti-Icing: The Critical Challenge for Snowmaking Intakes
Here is the paradox of snowmaking intakes: the screen must function perfectly in freezing conditions, because freezing conditions are exactly when snowmaking operates.
Snowmaking systems operate during the coldest nights of the season, precisely when the frazil ice risk is highest. The mountain streams that feed ski resort intakes are turbulent, shallow and exposed to very cold air: ideal conditions for supercooled water to form ice crystals on the wedge wires. An unprotected screen can block completely within hours during a supercooling event, shutting down snowmaking at the worst possible time [10][11].
This is why anti-icing is not optional for snowmaking intakes: it is a core specification requirement. ADENCO integrates anti-icing systems into the screen assembly during manufacturing. These systems are designed specifically for the Coanda screen geometry and the site's temperature range. Options range from electric heating elements and warm water recirculation to heated air diffusers and insulated enclosures, depending on the severity of the cold climate and the availability of electricity at the intake.
For a complete technical guide to anti-icing methods (including the science of frazil ice formation, 5 prevention technologies compared, and selection criteria for each) see: Anti-Icing Technology for Water Intake Screens.
How to Size a Snowmaking Intake
Step 1: Determine Peak Water Demand
Snowmaking water demand depends on the area of ski runs to be covered, the target snow depth, and the available production time (hours of freezing temperature per night).
Key reference data:
- Water per cubic metre of snow: Approximately 0.5 m³ of water produces 1 m³ of machine-made snow [3]
- Water per hectare of ski run: 3,000–4,000 m³ per hectare per season for the initial base layer of snow [12][13]
- Peak flow rates: Large systems pump 5,000+ gallons per minute (315+ l/s); mid-size resort systems typically operate at 50–300 l/s [1][14]
Step 2: Size the Intake Screen
A Coanda screen delivers approximately 140 l/s per metre of weir width on the US Bureau of Reclamation (USBR) reference geometry [6], which is the generic industry baseline used for preliminary planning. ADENCO's own series are rated at 35, 67 and 150 l/s per metre for the ADENCO-45, ADENCO-70 and ADENCO-127; once you select a specific model, use that model's rated capacity from the products page. For a planning estimate, calculate required weir width:
| Resort System Size | Typical Peak Flow | Required Weir Width | Typical Configuration |
|---|---|---|---|
| Small (single ski run, private) | 10–30 l/s | 0.1–0.2 m | Single small panel |
| Mid-size (5–15 ski runs) | 50–150 l/s | 0.4–1.1 m | 1–2 panels |
| Large resort (25+ ski runs) | 150–500 l/s | 1.1–3.6 m | Multi-panel array |
| Major destination (50+ ski runs) | 500–2,000 l/s | 3.6–14.3 m | Large multi-panel array or multiple intake points |
Step 3: Verify Available Head
Confirm that the intake site has at least 450 mm of available head between the normal water surface of the river and the outlet pipe elevation. Mountain stream sites almost always have sufficient available head due to the natural gradient [5][6].
Step 4: Specify Anti-Icing Requirements
For any site where water temperature may approach 0°C during the snowmaking season (virtually all sites), include anti-icing specifications. Provide minimum air temperature, minimum water temperature, and whether electricity is available at the intake location.
Step 5: Specify Material and Slot Width
- Material: 304 stainless steel is standard for freshwater mountain streams. Specify 316L if the raw water has elevated mineral content or if road de-icing salt (runoff from salted roads) could enter the water body.
- Slot width: 1.0 mm is recommended for snowmaking intakes. This provides fine screening that removes all debris harmful to nozzles and pumps, and can be supplied to meet fish protection requirements where applicable.
Reclaimed Water Snowmaking: The Emerging Trend
A growing number of ski resorts are turning to treated wastewater (reclaimed water) for snowmaking, in response to water scarcity, environmental regulations, and sustainability goals.
- Big Sky Resort (Montana) received approval in 2025 to use up to 23 million gallons of reclaimed water per year for snowmaking, with plans to expand to 44 million gallons in a second stage [15].
- Arizona Snowbowl became the first resort to use 100% reclaimed water for all snowmaking in 2012 [16].
- Yellowstone Club (Montana) began making snow from reclaimed water in the 2023–2024 season with a $12 million system [1].
- Over a dozen resorts across 8 U.S. states, Canada, Switzerland, and Australia now use reclaimed water for snowmaking [15].
Implications for intake screen specification: Reclaimed water has been treated to remove most suspended solids, but residual particles, biofilm fragments, and precipitated minerals can still be present. Intake screening for reclaimed water systems requires:
- Narrower slot widths (0.5–1.0 mm) to catch residual particles
- 316L or higher material grade due to elevated chloride and chemical residuals in treated water
- Compatibility with UV sterilization: the screen must not introduce contaminants that reduce UV effectiveness
Even in reclaimed water systems, a Coanda screen provides reliable first-stage screening that protects the high-pressure pump system: the most expensive component in the snowmaking infrastructure.
Frequently Asked Questions
What water filtration does a snowmaking system need?
Snowmaking requires multi-stage filtration: primary intake screening (0.5–2.0 mm) to remove debris and organic material at the intake, secondary pre-filtration (200–500 microns) at the pump house, and final filtration to 100 microns before distribution to snow guns. The primary intake screen is the most critical stage because it determines the debris load on all downstream equipment.
Can a Coanda screen be used for snowmaking water intake?
Yes: Coanda screens are ideally suited for snowmaking intakes. They operate without electricity (critical for remote mountain locations), provide fine screening down to 0.5 mm in a single stage, self-clean without intervention, and protect fish in environmentally sensitive mountain streams. With ADENCO's anti-icing systems, they function reliably in the freezing conditions required for snowmaking.
How much water does snowmaking use?
Approximately 0.5 m³ of water is required to produce 1 m³ of machine-made snow. Covering one hectare of ski run with base snow requires 3,000–4,000 m³ of water per season. A mid-size resort with 50 hectares of snowmaking coverage may consume 150,000–200,000 m³ per season.
What water temperature is too cold for snowmaking intake operation without anti-icing?
Any water temperature below approximately 1°C creates frazil ice risk on the wedge wire surfaces. Since snowmaking operates exclusively when air temperatures are below 0°C, virtually all snowmaking intake sites require anti-icing equipment. ADENCO integrates anti-icing into the screen assembly during manufacturing. For the full guide to anti-icing methods and selection criteria, see: Anti-Icing Technology for Water Intake Screens.
What slot size should I use for a snowmaking intake screen?
We recommend 1.0 mm slot width for snowmaking intakes. This removes all debris that could damage nozzles (leaves, needles, insects, coarse sediment), provides the level of fine screening that reduces the load on downstream filters, and can be supplied to meet fish protection requirements. Slot widths narrower than 1.0 mm provide minimal additional benefit for snowmaking water quality.
Can I use reclaimed water for snowmaking?
Yes, with proper treatment and the required permits. Over a dozen ski resorts in the U.S., Canada, Switzerland, and Australia already use treated wastewater for snowmaking. Reclaimed water must be treated to A-1 classification or equivalent standards. A Coanda screen with 0.5–1.0 mm slots in 316L stainless steel provides appropriate first-stage screening for reclaimed water systems.
How do I protect snow guns from clogging?
The most effective protection starts at the intake, not at the snow gun. A Coanda intake screen with 1.0 mm slots removes the debris that causes nozzle clogging before it enters the pipeline. Combined with pump house filtration to 100 microns, this two-stage approach prevents virtually all clogging. Individual snow guns include their own final mesh filters as final protection.
What is the cost of a snowmaking water intake system?
A single ADENCO screen unit costs €1,500 to €5,000 ex works, depending on slot width, material grade, screen dimensions and the number of units. Anti-icing equipment and the concrete works add to the total project cost, depending on site conditions. For a detailed breakdown of the 11 factors that determine Coanda screen pricing, see: How Much Does a Coanda Screen Cost?.
References
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"Snowmaking." Wikipedia. Retrieved April 2026, from https://en.wikipedia.org/wiki/Snowmaking
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"Snow Knowledge." SnowMakers. Retrieved April 2026, from https://snowmakers.com/snow-knowledge/
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BOLLFILTER. "Snow Machines Water Filtration." Retrieved April 2026, from https://www.bollfilter.com/applications/treatment-of-water-systems/snow-machines
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TechnoAlpin. "Water & Air for Snowmaking Systems." Retrieved April 2026, from https://www.technoalpin.com/en-us/total-solution/water-and-air-supply/
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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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"The Coanda Effect." International Water Power & Dam Construction. Retrieved April 2026, from https://www.waterpowermagazine.com/analysis/the-coanda-effect/
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U.S. EPA. (2014). "Final Regulations for Cooling Water Intake Structures." Federal Register, 79 FR 48300.
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UK Environment Agency. "Screening for Intake and Outfalls: A Best Practice Guide." Retrieved April 2026, from https://www.gov.uk/government/publications/screening-for-intake-and-outfalls-a-best-practice-guide
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"Bottom-type intakes (Coanda screen, Lepine water intake, etc)." FIThydro Wiki, EU Horizon 2020. Retrieved April 2026, from https://www.fithydro.wiki/index.php/Bottom-type_intakes_(Coanda_screen,_Lepine_water_intake,_etc)
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Daly, S.F. et al. (2023). "Prevention of Water Intake Blockage by Ice during Supercooling Events." Journal of Cold Regions Engineering, Vol. 37, No. 1. ASCE.
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Gebre, S. et al. (2014). "Performance of Coanda-Effect Screens in a Cold Climate." Journal of Cold Regions Engineering, Vol. 28, No. 4. ASCE.
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"Snowmaking in Austria: Energy Consumption, Water Turnover, CO₂ Emissions." Current Issues in Sport Science (CISS). Retrieved April 2026, from https://ciss-journal.org/article/view/11546
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"Construction of a Quantitative Model for Ski Resort Water Demand." Nature Scientific Reports (2024). DOI: 10.1038/s41598-024-76006-8
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"Snowmaking at Cypress Mountain." Retrieved April 2026, from https://www.cypressmountain.com/snowmaking
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"State Approves Big Sky Resort Plan to Turn Wastewater into Snow." Montana Free Press, October 2025. Retrieved April 2026, from https://montanafreepress.org/2025/10/07/state-approves-big-sky-resort-plan-to-turn-wastewater-into-snow/
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USBR. "Prevention of Frazil Ice Clogging of Water Intakes." REC-ERC-74-15 (1974). Retrieved April 2026, from https://www.usbr.gov/tsc/techreferences/hydraulics_lab/pubs/REC/REC-ERC-74-15.pdf
Published by ADENCO: Advanced Engineering Coanda Intake Screens. ADENCO provides Coanda screens with integrated anti-icing systems designed specifically for snowmaking water intakes in alpine environments. Contact our engineering team for a site-specific snowmaking intake design and quote.