Author: Glenn Telfer

Science Museum of Virginia Expansion Wins Regional Award

The Science Museum of Virginia, located in a former train station along West Broad Street in the City of Richmond, is a beacon of discovery in Virginia. First opened 40 years ago, the museum strives to serve as a catalyst for inspiration and place that sparks curiosity. The Science Museum attracts hundreds of thousands of guests annually through exhibits, artifacts, and interactive technologies. This popularity also posed challenges for the institution and created a need to expand the existing facility in order to provide greater opportunities to meet the Science Museum’s mission. Under the leadership of Rich Conti, the Science Museum embarked on an ambitious campaign to renovate the existing museum and expand with the addition of the Dewey Gottwald Center, a $12 million facility that offers dynamic spaces for events and meetings. Highlighting the success of this project, it was recently honored by Engineering News-Record as the ENR Mid-Atlantic Best...

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What I’ve Learned About Bioretention: Part 2

Read Part 1 of this post here. 2. Bigger is not better Like most everything we design, when big things fail, they fail in a big way. Bioretention works best in applications where the drainage area to an individual cell is less than about a quarter acre. Larger bioretention areas are more likely to fail due to erosion because of larger flows, creation of low spots due to variations in the surface, and clogging of the surface layer. This can be avoided by dividing the area into multiple cells with smaller drainage areas. [caption id="attachment_6401" align="aligncenter" width="770"] Larger basin divided into three cells[/caption]   The largest bioretention area I know of is an example of this. Designed by others, it collects runoff from several acres at a highway rest stop. The measures designed to evenly distribute incoming flow have been overwhelmed by large flow rates, the engineered soils mix layer does not drain quickly enough, and...

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What I’ve Learned About Bioretention: Part 1

Bioretention areas (also sometimes called rain gardens) are a very useful tool in the toolbox of stormwater treatment BMPs. They provide a high level of pollutant removal and runoff volume reduction, and, if properly designed, require little maintenance. Bioretention was developed to mimic the hydrology of a natural forest. It consists of a shallow (typically 4-8 inches) basin with 3 inches of mulch and a variety of selected plants on the surface that can accommodate periodic flooding and drought. Under the mulch is a layer of engineered soil mix (typically 12-36 inches). The basin collects surface runoff and filters out nitrogen and phosphorus (nutrients for plants, but pollutants in stormwater) as water passes through the engineered soil mix. Water is absorbed by surrounding soils or is collected by an underdrain. The plants convert the nitrogen and phosphorus collected in the engineered soil mix into woody plant matter and leaves. If designed and...

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Grasses for the Masses

Glenn Telfer, Technical Leader for Sustainable Design in our Richmond office, is making a lasting, postive impact by taking part in the Chesapeake Bay Foundation’s (CBF) Grasses for the Masses program. He is volunteering to grow aquatic grasses from seed and plant them in the Chesapeake Bay. Aquatic grasses are a vital part of the chain of life in the Bay. Also know as submerged aquatic vegetation (SAV), they provide essential habitat and shelter for the young of many species, including crabs and fish. Without the shelter provided by thick grass beds in shallow waters near the shoreline, the young are exposed to predators. Glenn volunteered to be part of this program because it links with his expertise in stormwater design. “On every project, I design stormwater systems to reduce nutrient pollution into the Chesapeake Bay. Re-establishing the aquatic grass beds also helps to achieve the goal of a cleaner Bay.” Aquatic vegetation...

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Big Changes Coming to Virginia Ms4 Compliance

A massive project by the Hampton Roads Sanitation District (HRSD) has the potential to be a game changer for Chesapeake Bay Total Maximum Daily Load (TMDL) compliance for MS4 permitees. When complete in 2030, HRSD’s project SWIFT ( will treat all the sewage from HRSD to drinking water standards and inject the treated water into groundwater aquifers. The main benefits to this project are that millions of pounds of nitrigen, phosphorus, and total suspended solids will no longer be discharged to the York and Lower James watersheds and injecting water into groundwater aquifers should result in a decrease or reversal of sinking land elevations. HRSD plans to fund the projected $5 billion cost by raising sewage rates. In exchange, HRSD will give credits to the cities and counties which make up their service area. If allowed by DEQ, these MS4 permittees will be able achieve Cheasepeake Bay TMDL compliance at no additional...

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