Maintenance and Repair of the Hartford Flood Control System

Fuss and O’Neill has been working with the City of Hartford to maintain and repair components of their flood control system for many years. The Hartford system is considered to be one of the most complex flood control systems in New England. 

The system is comprised of:

• 34,000 feet of Earthen Dikes
• 4,400 feet of Concrete Floodwalls
• 6 Pumping Stations
• 2 Stormwater Runoff Storm Ponds
• Park River Conduit (16,300 feet)
• Park River Auxiliary Conduit (9,100 feet)
• 2 Other Pressure Conduits

In 2008, Fuss and O’Neill teamed with another engineering firm to provide the Federal Emergency Management Agency (FEMA) with the proper documentation and certifications in order for the flood control system to become fully accredited. This consisted of demonstrating that the flood control system met the hydraulic and structural standards required to be considered by FEMA as providing protection from a 100-year flood event.

Since assisting with the FEMA accreditation process, Fuss & O’Neill has provided multidisciplinary project support (water/wastewater engineering, structural engineering, MEP engineering, and site/civil engineering) to maintain and repair the Hartford Flood Control System. These flood control, climate resilience, and stormwater management and compliance projects include the following:

Quarterly and Annual Inspections

We provide routine quarterly and annual inspections of the Hartford Flood Control System in accordance with the City’s System-Wide Improvements Framework (SWIF), which Fuss & O’Neill helped develop. The quarterly and annual inspections conducted by Fuss & O’Neill include the following:

• Perform quarterly inspections of the City’s six stormwater pumping stations.
• Perform annual inspections of the 8 major drainage structures and 13 Park River conduit gate valves that are serviced by the Metropolitan District Commission.
• Perform megger testing at all six of the City’ stormwater pumping station.

Levee Repairs

Our water/wastewater engineers have prepared design and permitting documents and provided construction administration services for repairs to the levee system. Repairs have included:

• Repairing animal burrows along the levee system. Burrows created by animals can lead to rapid levee failure if not addressed.
• Evaluation and repair of the levee toe drain system.
• Replacement and repair of disturbed rip rap along the levee.

Hydrologic and Hydraulic Interior Drainage Analysis

Fuss & O’Neill performed an interior drainage analysis in accordance with 44 CFR § 65.10 (b)(6) in order to satisfy FEMA requirements associated with the accreditation of the Hartford Levee and Flood Control System. The interior drainage components include pump stations and pressure conduits that convey stormwater and floodwaters past the line of protection (the levee) to the Connecticut River. The purpose of the analysis is to identify whether the 1% annual chance ponding level of stormwater within the protected area creates flooding of greater than 1 foot in depth.

Stormwater Pumping Station Improvements

Fuss & O’Neill assessed pump capacity and condition at six stormwater pumping stations that serve the flood control systems. The pumping stations have pumps that range in size from 16 to 36 inches, with capacity from 3,500 to 45,000 gpm per pump, and discharge against heads ranging from 5 – 38 feet.

Fuss & O’Neill’s water/wastewater engineers conducted condition assessments, including capacity testing, visual inspection of components, ultrasonic vibration monitoring, electrical system testing, and megger testing, to determine the integrity of the system, to ensure compliance with FEMA and U.S. Army Corps of Engineers Flood Control System design, and to ensure compliance with operation and maintenance requirements.

Our team developed a comprehensive plan for repairs and upgrades and provided engineering and construction support services for the highest priority pumping station repairs. We designed Phase I improvements, consisting of the most critical repairs, to satisfy the U.S. Army Corps requirements. Projects included 12, 36-inch valve and operator replacements, safety improvements, and pump rotating assembly repairs at 4 of the 6 pumping stations. A measurement system was custom designed and installed in the pump’s suction and discharge piping to compare actual performance with published pump curve data.

Auxiliary Conduit Sediment Removal and Storage Ponds Sediment Removal

Sediment removal was necessary at an auxiliary conduit and at the North and South Meadows storage ponds. Sediment was removed as part of preventative maintenance to restore to the auxiliary conduit and storage ponds to design conditions. We prepared design and permitting documents and provided construction administration for these projects. In total, approximately 8,200 cubic yards of sediment was removed from the auxiliary conduit and approximately 43,000 cubic yards of sediment was removed to restore the North and South Meadows storage ponds.

Folly Brook Conduit Rehabilitation

The Folly Brook Conduit is located along the Hartford/Wethersfield town line. Our team inspected the conduit and evaluated the conduit’s structural integrity. Several alternatives to restore the integrity of the structure were evaluated; however, the following work was recommended for repair:

• Install a concrete invert on the bottom of the corrugated metal pipe section.
• Install a concrete invert where the original invert was missing.
• Repair deteriorated areas of concrete and seal cracks.

Our team prepared contract documents and provided construction administration services for the rehabilitation of the Folly Brook Conduit mentioned above.

Hartford Levee Breach Analysis

The City of Hartford was required to supply FEMA with the proper information and certifications for the Hartford Flood Control System to become fully accredited. For Hartford’s Flood Control system to obtain a favorable inspection rating, one required element is a comprehensive Floodplain Evacuation Plan.

As part of this certification effort and the City of Hartford’s ongoing effort to review and update its flood emergency response planning, Fuss & O’Neill performed a hypothetical breach analysis of the Hartford levee. The resulting flood estimate data are meant to serve as a basis for flood response planning for all functional emergency annexes, including the evacuation annex.

Hartford Operation and Maintenance Manual

Fuss & O’Neill developed the City of Hartford’s Flood Control Operation and Maintenance (O&M) Manual. This manual provides instructions for the operation and maintenance of the Hartford Local Protection Project, which was designed to provide flood protection within the City of Hartford from the Connecticut River, Park River, North and South Branches of the Park River, Gully Brook, and Folly Brook. The manual presents detailed information to be used as a guide to comply with existing federal flood control regulations.

As part of Fuss & O’Neill’s involvement in the accreditation process and development of the O&M Manual, we routinely provide administrative and technical coordination with FEMA and the U.S. Army Corps of Engineers.

The work completed by Fuss & O’Neill has enabled the City of Hartford to maintain USACE “active” status. The consequences of not maintaining USACE “active” status are profound. If the flood control system were to fail and receive an “Unacceptable” rating from the USACE, levee accreditation with FEMA would be jeopardized, which would impact insurance rates for residential and commercial properties currently protected by the levee. There are 3,000 acres in the City that are protected by the flood control system, and skyrocketing insurance rates would essentially make the bulk of the City of Hartford un-insurable.