Sindall Brook Stabilization and Restoration

The eastern portion of the Town adjacent to Sindall Brook was experiencing flooding and property damage during significant rainfall events. Suspecting incremental effects of continued development of the upper reaches of the watershed, the Municipality retained Tectonic to review the stormwater management design approved for a project located in the watershed, but under the jurisdiction of an adjacent municipality. Tectonic performed a detailed study of the one square mile watershed including: field reconnaissance, homeowner meetings and outreach, hydrologic analysis and modeling using HEC-HMS, and hydraulic modeling (using HEC-RAS, HEC-HMS, manufacturers proprietary channel design software, or FHWA HY-8, depending on the location being analyzed) of six locations where mitigation of the stream banks was warranted to address erosive conditions. Final design phase services included preparation of plans, details, and specifications for the implementation of the stabilization by the Municipality.

Reconstruction of Slope Failures

Heavy rainfall from storms that occurred in late June and early July of 2006 produced significant runoff and stream flow that caused slope failures along Turner Hill and Pumpkin Hollow Roads in the Town of Davenport, Delaware County, New York. Slopes varying from 30 to 60 feet in height from streambed to roadway elevation failed at four locations.

Tectonic was engaged by the Town to assess the situation, provide immediate recommendations for maintaining partial temporary traffic flow and to document the conditions and assist with developing preliminary remedial repair alternates as needed to obtain funding from the State Emergency Management Office (SEMO) and the Federal Emergency Management Agency (FEMA).

Tectonic quickly mobilized staff and performed investigation phase services consisting of a site reconnaissance, topographic surveys and geotechnical investigations followed by design development phase services consisting of review of methods proposed by FEMA for repairing each failed area, evaluation of alternate remedial repair methods which were more desirable based on constructability, long term maintenance, cost and duration of construction, and preparation of cost estimates.

Following FEMA’S issuance of approved project work plans acceptable to the Town, Tectonic prepared design drawings and specifications for contract bidding and construction. Due to the steepness of the slopes and access constraints, the slopes were stabilized using steel H-pile and precast concrete panel retaining walls with the H-piles socketed into bedrock and tied-back with rock anchors.

Multi-Jurisdictional Hazard Mitigation Plan

The Disaster Mitigation Act of 2000 requires all local governments to have approved Hazard Mitigation Plans in order to receive Hazard Mitigation Grant Program project grant funds. The Town of Warwick joined with the Villages of Warwick, Florida and Greenwood Lake to develop a multi-jurisdictional Hazard Mitigation Plan. The Town of Warwick contains three villages and sixteen hamlets, and encompasses a total area of the 105 square miles. Tectonic prepared the Hazard Mitigation Plan which focused on developing strategies for taking preventative measures to reduce possible future disasters on the community.  The Plan was approved by FEMA and the NYSDHSES and adopted by each community. The communities were successfully awarded a grant from FEMA as a subgrantee to the NYSDHSES.

Wickham Water District

The Wickham Water District serves approximately 350 homes in which the water supply facilities are located on six separate sites on the District edges.

Tectonic served as the Town Engineer for Warwick and assisted the Town with the completion of several rehabilitative and new construction projects for the Wickham Water District.

Tectonic provided survey, engineering design, permitting, analytical testing, subsurface, and construction administration and inspection services for the following projects:

  • District expansion approval
  • Repair of an aging 200,000 gallon water storage tank
  • Construction of a new 100,000 gallon water storage tank
  • Chemical treatment system and building for sequestering metals
  • Greensand Filter system for iron and manganese removal
  • New treatment/disinfection building/distribution main
  • 2 new municipal wellsMany of the projects required careful coordination to ensure construction efforts did not impact continued water service for the existing District water users.

Old Mamaroneck Road (CR26) Reconstruction

The rehabilitation of Old Mamaroneck Road included intersection, sidewalk, drainage and pavement improvements for an approximate length of two miles through a highly-traveled urban residential corridor.

Tectonic developed construction contract documents, including Maintenance and Protection of Traffic Plans associated with this project. The reconstruction work involved installing new concrete curb and additional drainage structures, milling the roadway, replacing traffic signal loops and handicap ramps, repaving with asphalt binder and top course, replacing signage and re-striping the roadway. Surveying and mapping were also performed requiring the establishment of right-of-way lines.

Haverstraw Streetscape

The Village of Haverstraw is a village situated along the Hudson River Waterfront which is actively undergoing revitalization.

The Main Street and Broadway Streetscape Improvement project is a part of this revitalization which involves the design and construction of streetscape improvements in the village. This project will include:

  • replacement of sidewalks, curbing and pavements
  • installation of street lighting, signage and landscaping, and
  • signalization improvements Tectonic will provide Construction Supervision and Inspection Services associated with the construction phase activities. The proposed sidewalk, curbing and lighting improvements will help to facilitate better traffic flow and provide safer pedestrian access points with crosswalks. The project is funded on the local and federal level and is a Locally Administered Federal Aid Project with oversite by the NYSDOT – Region 8.

Dial-a-Bus Storage Facility

For many years, Tectonic has provided professional engineering services at various locations throughout the Town of Warwick. In partnership with Orange County, the Town of Warwick obtained grants and funding from the Federal Transit Administration for a bus storage facility. The proposed garage would house 12 buses and facilitating dispatch operations within a 9,100 square foot facility.  The buses serve the southern portion of the County including the towns of Blooming Grove, Wallkill, Monroe/Harriman, Goshen, Chester, Warwick, and their incorporated villages.

Tectonic assisted the Town with obtaining funding and permits to construct the garage. Additional services included:

  • Preparation of a Stormwater Pollution Prevention Plan (SWPPP) and a National Environmental Policy Act (NEPA) screening report.
  • Addressing potential impacts upon historic resources, wetlands, ecologically sensitive areas and endangered species while providing additional guidance for project compliance with federal and state applications.
  • Geotechnical subsurface investigations.
  • Surveying services.
  • Cost estimating.

Towards completion of the project, Tectonic was responsible for updating and re-evaluating the SWPPP and NEPA checklist in order for the project to move forward.

Glenmere Lake Dam

Glenmere Lake Dam, a large, high hazard dam, impounds a water supply reservoir with a surface area of 328 acres and drainage area of 2.4 square miles. The dam is approximately 600-feet long and consists primarily of an earth embankment with a maximum height of 24 feet, partly supported by masonry stone and reinforced concrete walls. The crest of the dam serves as a two lane paved County roadway. Glenmere Lake also provides habitat for the largest known population of the endangered, Northern Cricket Frog (Acris crepitans) in New York State.

Tectonic prepared an Engineering Assessment and Emergency Action Plan for the dam that included the following:

• Hydrologic and hydraulic analyses
• Dam breach analyses
• Inundation mapping and hazard class evaluation
• Incremental damage assessments
• Spillway capacity evaluation
• Subsurface investigation
• Stability and seepage analyses
• Topographic and bathymetric surveys

As a result of the Engineering Assessment, the spillway capacity and dam stability were found to be deficient. Tectonic performed additional studies including an evaluation of raising the dam embankment and enlarging the spillway to increase storage and spillway capacity to prevent overtopping.

Tectonic prepared permit application documents, design plans, cost estimates and construction documents to complete the necessary improvements and modifications that include modifying the alignment of the dam to reduce the length of the dam by more than 50 percent, installing a toe drain to control seepage, and replacing the existing spillway and spillway conveyance conduit.

The relocation and shortening of the dam was a unique approach that eliminated the need for costly environmental remediation, reduced impacts to the Northern Cricket Frog population and allowed construction to proceed without lowering the reservoir which would have drastically impacted the water supply and endangered species.

Construction is currently underway and Tectonic is providing resident engineering inspection and material testing services and also monitoring of the Northern Cricket Frog as required by the NYSDEC.