Stormwater Treatment

Together, with Environment21, Gainey’s provides a full line of Engineered Stormwater Treatment products that can be quickly and easily sized by our Stormwater Engineers specifically for your site.

  • Rapid response turn around on all designs within 24 hours
  • Easy to use sizing/pricing request form
  • Easy to find specifying documents

Call for an estimate today!

Click Here for an Interactive Design Worksheet



The “UniStorm” provides primary treatment of stormwater using precast manholes. The Unistorm system employs low-head loss internal flow diffusers and flow distributors to reduce stormwater turbulence and improve flow distribution. This allows on-line operation to eliminate pollutant bypassing during high-intensity rainfall events. Its design allows it to help you meet the EPA goal of 80% TSS removal efficiency and 40% phosphorus removal. Shallow sump depth of 4-5 feet reduces excavation costs and facilitates pumpout. Unistorm systems are ideal for sites with limited space and/or difficult soil conditions.



The V2B1 is the flagship of Environment21.  Its unique standard pre-cast concrete two manhole design allows it to help you meet the EPA goal of 80% TSS removal efficiency. The inlet manhole has a tangential mounted inlet pipe that creates a swirl flow pattern, which improves flow distribution and reduces turbulence, thus enhancing sedimentation settling.  And, as with all environment 21 products, maintenance is a cinch with access openings to all stages and a clear view to the sump.

KoalaClick here for demonstration video!

ESK Koala

ESK Koala is the latest in European Technology for High Efficiency Oil Water Separation. Through the application of coalescing media the ESK achievies removal efficiencies as low as 5 PPM (Parts Per Million) at flow rates in excess of 5000gpm, making it one of the most competitive high efficiency oil/water separators in the country.

Optional accessories include catastrophic spill valves, high level alarms, and high efficiency grit chambers. The ESK Koala is the perfect product for your industrial or commercial application.

Catch Basin


Envirokleen Catch Basin Inserts remove hydrocarbons, organically bound metals, sediments and other organics from stormwater and industrial runoff.

  • Exceeds 80% sediment removal efficiency
  • By-pass system prevents flooding or ponding during high flow storm events.




CONCRETE: Class 1 concrete with design strength of 4500 PSI at 28 days
REINFORCEMENT: Conforms to ASTM C478 – “Standard Specification for Precast Reinforced Concrete Manhole Sections”
CASTING: Cast iron man hole ring and cover shall be nominal 24 inch and shall be traffic duty
SEALANT: Joints shall be watertight joints using a butyl mastic sealant conforming to ASTM C 990
TREATMENT: Designed for 50 – 80% removal efficiency for sandy sediment (specific gravity of 2.65) at a Water Quality Event Peak Flow Rate of 0.70 cfs per impervious acre

 Literature Available

Unistorm UniStorm
V2B1 V2B1
Koala ESK
Envirokleen Envirokleen


Looking for a CAD drawing? Contact Cyndi Glascock at

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