CASE STUDY

North Hudson Sewerage Authority

Proactive stormwater design regulations mitigate flooding and reduce combined sewer overflows to the Hudson River.

The Challenge

NHSA faced considerable regulatory and community pressure toaddress CSOs and flooding. With nearly 190,000 customers inone of the most densely-populated urban areas in the U.S., limitedland availability for stormwater runoff storage, and a constantlychanging environment and watershed, the Authority needed toconsider a new approach to advance their mitigation and waterquality goals.

The Solution

With a dense urban service area and limited right of way,traditional approaches to create additional system capacity foraddressing flooding and CSOs were not feasible. Instead, NHSApartnered with commercial developers to maximize storage andwet weather capture with smart detention.

In 2018, NHSA implemented new stormwater design andconnection rules requiring automated flow controls on newdevelopments disturbing 10,000 SF or greater. The ruleaccelerated an integrated network of continuous monitoringand adaptive control (CMAC) sites across the sewershed,helping NHSA protect people, property, and environment whilemeeting regulatory compliance requirements.

At a Glance

• $0.04/gallon wet weathercapture vs. >$1.00/gallonwith passive controls
• 59−84% annual wet weathercapture
• Real-time controls as arequirement for propertydevelopment

“Opti provides a factorof safety for balancingwhat we can store withwhat we can treatdownstream.”

Fred Pocci, P.E.
Authority Engineer, North
Hudson Sewerage Authority

ECONOMICAL
95% Savings
CAPEX

RESILIENT75% Flow Reduction
Average Annual Wet Weather
Outflow Volume

PEACE OF MINDNetwork Insights
SCADA Integration

Results

Since 2018, Opti has been actively controllingseveral stormwater assets. Using weatherforecasts, inflow models, and real-time data,Opti active controls improve wet weathercapture and minimize peak flows to thecombined sewer system, thereby mitigatingCSOs and flooding. Over the course of twoyears, Opti-controlled sites fully captured86% of storms with no outflow, savingcapacity at the downstream treatment plantduring peak loading times.

Storage Reduction

NHSA’s new stormwater regulations put an emphasis on more storage. Meeting peak flowrequirements with an undersized system could only be met by integrating active controls orconstructing comparable storage elsewhere.

With Opti active controls, a building’s detention tank could be downsized by an estimated 30% andcontinue to meet NHSA’s volume capture requirements. This smaller, more efficient storage approachsaves money and space in constrained projects. Opti’s continuous monitoring and adaptive controls(CMAC) is now the primary smart active controls solution used by area developers.


Opti prevented 75% of thestormwater runoff enteringSouthwest Park fromreaching the combinedsewer during wet weather.
The site combines passive green spacewith Opti adaptive controls to meet localstormwater management needs. It isNew Jersey’s first resiliency park withintegrated green stormwaterinfrastructure (GSI) to mitigate flooding.

About OptiRTC

Opti ,an Aliaxis company, is the leading provider of digital adaptive stormwater control solutions.With over 300 deployments to date, Opti empowers customers and partners to address theimpacts of climate change, aging infrastructure, urbanization, and water pollution, enabling themto secure the sustainability of our communities and natural resources Opti’s cloud-basedplatform optimizes stormwater asset performance through instant actionable insights to provideeconomic savings, resilient solutions, and peace of mind. With our commitment to innovation, weare driving a resilient and brighter future for all.