Cardinal Engineering Associates - 55 years of excellence

Cardinal Engineering was retained by The Town of New Fairfield to analyze the East Lake Brook in the Town of New Fairfield. Five roads cross the brook. The impacts of 10- to 100-year flows on the roadway crossings and the adjacent properties were studied. The watershed of the East Lake Brook has an area of 340 acres and is a public water supply watershed.

Hydraulic computations were performed using the SCS TR-20 computer program. For the existing structures, the analyses determined the 10- to 100-year water surface elevations and discharges. The results showed that all the roadway crossings were overtopped for flows between 5- and 25-year return frequency. The properties immediately upstream of the roadway culverts and adjacent to the brook were being flooded for relatively low storms.

Two design alternatives to alleviate the flooding in the area were considered:

The first alternative involved the replacing the existing structures with adequately sized structures to pass the 100-year flows with one foot of freeboard and no additional storage.

The second alternative involved storage upstream of the second crossing and new structures to pass the 100-year flows. To achieve the necessary storage volume, 7,000 c. y. would have to be excavated, most of it in wetland area. The road would have to be raised 4ft, for a length of 250ft. The computations and cost estimates showed that the first alternative was a more cost effective, with minimal environmental impacts.

Cardinal designed adequate structures at all crossings (without changing the roadway profiles or providing additional storage) to pass the 100-year flows and eliminate roadway overtopping. The total construction cost for the three culverts was estimated to be $450,000.

East Lake Brook Bridge Design

After completing an extensive drainage study of the East Lake Brook, Cardinal was retained by The Town of New Fairfield to begin the design for the replacement of 3 small bridges and channel improvements to eliminate roadway overtopping and the flooding of several homes along the brook. Roadway storm drainage outlets were relocated to approximately 100 feet from the brook to improve water quality and meet Health Department regulations for work within a public water supply watershed. Construction was completed in the spring of 2011. Cardinal provided contract administration and resident engineering services for this project.

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