Virginia Beach Fourth Precinct

Retention Pond for Police Precinct Expansion

The renovation of the Virginia Beach Fourth Precinct in Kempsville more than doubled the size of police building. A lined retention pond was added to the project plan in order to meet stormwater regulations for the larger development.

About the Project

A new Virginia Beach Police Fourth Precinct Building replaced Kempsville’s former 6,017 square foot building. The new 17,000 square foot development increases the department’s office space, storage, training and processing areas.

Retention Pond Design: a Traditional Stormwater Solution

The back of the site has a large retention pond that manages the site’s stormwater runoff. This section of Kempsville has a high water table so the engineer specified several geosynthetic solutions to mitigate flood related problems.

After the basin was dug and graded, the contractor installed 44,000 square feet of 50 Mil PVC Liner. The 44,000 square feet included 11 custom-sized panels. The PVC Liner panels were seamed together using an adhesive. 

This liner creates impermeable barrier that prevents contamination of the groundwater system. A Nonwoven Geotextile Fabric was installed on top of the PVC Liner. The Nonwoven Geotextile cushions and protects the liner because if it were to be damaged, contaminants would seep through the barrier and compromise the liner’s function.

The retention pond is surrounded by a trench with nonwoven geotextile fabric and stone. This barrier is designed to slow sheet flow runoff and will also be the top point of water rise. Nine PVC Coated Gabion Baskets were then installed around the retention pond’s inlets. The rock-filled wire baskets are the pond’s forebays which collect sediment, slow the velocity of water and make maintenance easier. 

Single Net Straw Erosion Matting was installed on the pond’s embankments in order to stabilize the slopes. Following this install, the soil area was planted with wetland plants that are specified for wet ponds to absorb excess nutrients.