Arrowhead Drive Drainage Improvements - Nantucket, MA
In 2022 BEI was contracted to address on-going drainage issues occurring on Arrowhead Drive. The road is privately owned and generally services commercial properties. The existing grading of the road created a low point approximately at the midpoint, near the intersection of Spearhead Road.
In the spring of 2022, BEI began a survey and analysis of the conditions contributing to the ponding occurring during heavy rain events.
The following factors were determined to be contributing to the overall lack of performance:
In the spring of 2022, BEI began a survey and analysis of the conditions contributing to the ponding occurring during heavy rain events.
The following factors were determined to be contributing to the overall lack of performance:
- Very shallow grading
- Damaged shoulders
- A lack of edge treatment
A complete understanding of underground utilities in the area was critical to the design of stormwater management areas. Utilizing ground penetrating radar to map unmarked utilities allowed BEI to supplement record drawings and utility markings to create a complete survey of the area. Another important survey tactic was to create a dense grid of topographic shots along the roadway to establish a detailed contour surface of the existing roadway. The flat grading of the existing road meant that tenths of an inch, even hundredths, mattered.
The final design, as shown in the photo, included a complete regrade and roadway reconstruction in the area. New catch basins and subsurface infiltration structures were added as well as vertical curbing to contain and direct runoff. Layout of the final design required careful survey work. Like the existing road, the proposed elevations had a very tight tolerance. Finally, because of the grading tolerances required, concrete was utilized to surface the road.
In the last twenty years, the northeast has seen an increase in the intensity and frequency of large rain events. It is important that communities begin addressing underperforming drainage infrastructure. Ponding as seen at Arrowhead Drive causes obvious hazards to vehicles but it can also lead to premature failure of roadways and damage to adjacent properties. As seen inn other areas, such as the Manomet Ave project, uncontrolled runoff can lead to erosion along roadway edges or adjacent resource areas. BEI is proud to serve our communities to remedy these issues and protect the interests of communities and the environment.
