Overview
In 2019, the City of Hampton reselected Timmons Group for an annual contract for water resources engineering design services. The scope of the contract covers a broad range of services including studies, design and construction document preparation for stormwater, BMP, other infrastructure improvements, and tidal flood and shoreline protection projects. Representative projects and tasks include:
Hampton Roads Center Parkway Rain Garden
The City of Hampton received an NFWF grant to design and install a bioretention area on City property. Timmons Group was tasked to provide site survey, geotechnical services, civil and landscape construction design documents, and construction administration services. The bioretention / rain garden design followed the Virginia DEQ Stormwater Design specifications to the maximum extent possible to bring a positive aesthetic appeal to the median location while achieving 0.48 lbs/year total phosphorus removal and 3.98 lbs/year total nitrogen removal credits toward meeting the Chesapeake Bay TMDL nutrient goals. Timmons Group was given NTP in mid-October and completed the design and landscape plan documents in 2 weeks to ensure the City could meet the grant obligations to have the project constructed by the end of 2017. Construction was completed and accepted in the first week of December 2017.
Old Northampton Drainage Area Improvements Phase 3 – Langley Avenue
The City’s Capital Improvement Program (CIP) identified this project to address three measures: stormwater quality, localized flooding, and roadway improvements. After a site investigation and initial grading and drainage analyses, Timmons Group recommended improvement alternatives and costs to the City. The City opted to move forward with the design of the stormwater infrastructure and roadway upgrades to include a new storm sewer system and a hydrodynamic separator (HDS) to provide 20% phosphorus removal from the system. The existing road throughout the project was superelevated to drain to the proposed stormwater system. Timmons Group submitted final documents in 2016. The project was advertised in the Fall of 2016 and construction began in 2017. Timmons Group provided support through bidding and construction administration. Final walkthrough of the project occurred in August 2018. The City has received no stormwater-related complaints or noticeable flooding on the street since the improvements were made.
Kecoughtan Road BMP Retrofit
The City of Hampton identified a stormwater retrofit option in the James River Basin to provide Chesapeake Bay TMDL nutrient reduction credit and potentially reduce flooding, and tasked Timmons Group to determine the feasibility of constructing a Stormwater Wetland or other Best Management Practice (BMP). A site along an existing concrete lined ditch northwest of the corner of Kecoughtan Road and W. Sunset Road was identified as a possible location for a BMP in the previously developed Hampton River West and Southampton Watershed Study. Timmons Group completed a field investigation examining the site for apparent encroachments, drainage patterns, and overall site condition; performed the initial delineation of wetlands on site; and performed geotechnical services to determine soil profiles and the seasonal high-water table (SHWT). A Jurisdictional Determination (JD) package submitted to the U.S. Army Corps of Engineers (COE) was approved. Through discussions and review of the existing conditions, the BMP selected for design is a stormwater wet pond and the project has expanded to include a forest buffer area on a nearby parcel and replacement of the concrete lined channel with a greener channel section that will provide an ecological uplift to the area. All three of these design elements provide a water quality benefit of approximately 70 lbs of phosphorus removal. Final design was submitted in June 2021 with construction to follow shortly.
