Water-Gate™ Instant Underflow Dam


Prevent spills from spreading with the quickest way to dam up ditches and small streams. The Water-Gate Underflow Dam installs in minutes, with only 2 or 3 people.

Available sizes online:

  • DAM2125:   21”H x 25’L
  • DAM2825: 28”H x 25’L

Other available sizes: DAM3930: 39”H x 30’L.

Call 814-822-2004 to order or request pricing for DAM3930.



The Sandbag Alternative: Water-Gate Instant Underflow Dam

For decades, spill responders have been taught to build underflow dams to contain spills in small creeks and streams. They’re effective but take a lot of time and manpower to build. It’s also hard work carrying sandbags, pipes and tools to the water to get the job done. When you don’t have time or manpower to spare, Water-Gate Underflow Dams help your team get a dam in place in as little as ten minutes with as few as two people. That means the spill is contained faster, and cleanup can begin sooner.

Water-Gate Underflow Dams are 25’ – 30’ long and can weigh as little as 50 pounds, so they’re easy for one person to carry wherever they’re needed. Multiple sections can be linked together to span larger streams and rivers. Once the Dam is in place, adjustable underflow outlets allow the clean water underneath the surface to continue flowing. After the spill is cleaned up, just remove the Dam, wash it up, and reuse it over and over.

Water-Gate Underflow Dam Benefits:

  • Quick Deployment: Installs in minutes, with only 2 or 3 people.
  • Adaptable Design: Flexible material allows it to adapt to most stream and ditch bottoms.
  • Easy to Assemble: No special equipment needed. No filling with water or inflating with air needed. Simply unroll the dam, unfold the upstream flap and let the flow of the stream fill it.
  • No Anchoring Needed: Uses the weight of the water as it flows into the dam to weigh it down to the stream bottom.
  • Flow Regulation: Underflow holes built into the downstream side, so that you can regulate the flow on the upstream side and keep the spill contained.
  • Scalable: Multiple units can be attached together to make whatever length you need.
  • Reusable: Wash and reuse dozens of times.

Learn More:

Blog: Stop Sandbagging! Create Underflow Dams in Less than 10 Minutes

Case Study: Fast Daming Oil Spills in Hard-to-Reach Streams

Article: Ensure Rapid Response Time for Effective Spill Control

Training: Water-Gate Underflow Dam Instructions Videos (includes step-by-step instructions for deployment, removal, and storage)

On-Demand Webinar: Water-Gate Underflow Dam Webinar

White Paper: Underflow Dams in Less than 10 Minutes

On-Demand Webinar

On-Demand Webinar

Learn how to quickly stop oil spills on water with the Water-Gate Underflow Dam — presented by HalenHardy partner and trainer Troy Beaver with special guest Bill Dennis from Ardent Environmental Services.

Watch Now →



Stop Sandbagging! Create Water-Gate Underflow Dams in less than 10 minutes

Water-Gate Underflow Dams weigh less than 60 lbs and are easy to deploy

How it Works - Water-Gate Underflow Dam

How to Deploy Water-Gate Underflow Dam

How to Remove Water-Gate Underflow Dam

How to Connect Water-Gate Underflow Dams

How to Clean and Store Water-Gate Underflow Dam

Product Specifications

Product Specifications

Download Product Specs →

DAM2125 DAM2825 DAM3930
Water Retention Height 21” 28” 39”
Product Length 25 feet 25 feet 30 feet
Product Width
(Stream Bottom Skirt)
72” 97.5” 158”
Product Weight 37.4 lbs 59.5 lbs 150 lbs
Rolled Up Dimensions 16”W x 16”L x 20”H 16.5”W x 16.5”L x 25”H 21”W x 15”L x 37”H
Underflow Holes 13 14 19
Carrying Case YES YES YES

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