Hoyle Tanner prepared a hydrologic and hydraulic study for the replacement of a structurally deficient corrugated metal pipe (CMP) and reinforced concrete pipe.
The existing crossing is comprised of two adjacent culverts. The west culvert is a 4’ diameter reinforced concrete pipe and the east culvert is a 3’ diameter CMP. Due to its deteriorated condition and history of flooding in this area the Town of Derry is investigating replacement options for these culverts.
Hoyle Tanner performed hydrologic and hydraulic analysis and evaluated the existing opening of the culvert and recommended a new culvert type and opening that passes the 50-year flood event with a minimum of 1′ of freeboard per New Hampshire Department of Transportation (NHDOT) requirements. The recommended structure type will be 30’ in span. The project was fully funded through Town funds.
SERVICES
Hydraulic Analysis
Study
Final Design
Bid Process Administration
Construction Administration
From the blog
Learn about ongoing projects and the innovative processes we employ for our clients.
Construction is imminent for wastewater treatment facility (WWTF) upgrades at a small town in New Hampshire! With over 4,000 residents in Allenstown, upgrades may not seem as critical as...
Summer always seems to fly by, and summer 2025 was no different. Part of what accelerated the time for me was being involved in a fast-paced, interesting project for...
What drew you to Hoyle Tanner? I met Steph and Maggie at a networking event at my school where I had a really good conversation with them. I learned...
We’re proud to announce that David Jeffery and Tyler Heinrich have earned their Licensed Surveyor in Training (SIT) status in New Hampshire! David and Tyler are the newest additions...
BIM’s Importance Building Information Modeling (BIM) is a significant advancement in modern design and construction, and Hoyle Tanner is a leader in this design for wastewater facilities in New...
We are excited to announce that Structural Engineer Katie Welch has been appointed Director at Large for the Structural Engineers of New Hampshire (SENH) Board of Directors. The SENH...
At Hoyle Tanner, we have been deeply involved in the planning and design phases of the Millinocket Municipal Airport project. This project is a significant part of the town's...
Project Overview Hoyle Tanner is providing environmental engineering design and construction services for the Brighton Wastewater Treatment Facility (WWTF) upgrade. The Brighton WWTF operates a small lagoon system with...
Our team has been hard at work load rating bridges across Massachusetts. In simple terms, a load rating is an evaluation of a bridge to determine its capacity to...
