The shady trees we enjoy (or would like to) along Connecticut Avenue and other DC streets just got a boost. And in the process, DDOT’s stormwater management took steps toward a “culture change,” as a former DDOT official describes it.
Trees need legroom to grow healthy, luxuriant canopy. The District Department of Transportation (DDOT) is giving it to them, by raising the minimum soil volume standards for street trees. But it does more than that. Raising the soil volumes gives stormwater a place to go other than directly into our streams. And advisory neighborhood commissions (ANCs) can push developers to give even more legroom to our trees.
The new minimum standards for street tree soil are now an integral part of DDOT’s “Green Book” – its comprehensive, 198-page manual governing all street, sidewalk, and alley construction by DDOT and private developers. DDOT released the new standards for green infrastructure (GI) design, construction and maintenance in the public space between curbs and property lines on Earth Day: April 22, 2014.
This manual now includes green infrastructure standard drawings and specifications, and new plant lists and maintenance schedules. A companion illustrative guide, “Greening DC Streets: A Guide to Green Infrastructure in the District of Columbia,” summarizes GI opportunities and constraints in the District. The end goal: Reducing stormwater runoff and keeping our streams and rivers clean. Techniques include bioretention areas such as rain gardens permeable paving, and street tree design space.
DDOT points to development of its these standards as part of a nationwide shift to improve quality of life in cities and condition of waterways. DDOT’s draft standards were released for public comment in March 2013 and were available for public use thereafter. The standards have been piloted through several DDOT projects, including RiverSmart Washington. They were then refined based on the results. DDOT’s final GI Standards have been in effect since May 1, 2014. They are only available electronically, in PDF format.
Ronaldo T. (“Nick”) Nicholson, who recently completed a productive stint of public service as DDOT Chief Engineer, observed: “Since their initial roll out last year, DDOT has attempted to change the culture of urban stormwater management by applying these standards on all capital improvement and private sector projects in the public space.”
The team that prepared these standards included DDOT Urban Forestry Administration staff whom we in Forest Hills know well: John Thomas, Sharon Dendy, Earl Eutsler, and Joseph Burckle – as well as staffers from other parts of DDOT and from the Department of the Environment (DDOE). DDOT’s Meredith Upchurch, who headed the team, DDOT’s Reggie Arno, and DDOE’s Rebecca Stack and Steve Saari (among other team members) have looked into specific Forest Hills erosion issues.
The key to these new standards – is they are a minimum baseline. Sharon Dendy stressed that when she met with ANC 3F04 Commissioner Sally Gresham and me. And ANCs are key to getting developers to exceed those standards.
Although Dendy, as the reviewer of all public space projects for DDOT’s Urban Forestry Administration, can suggest ways for project developers to do even more than the minimum for tree canopy, UFA’s Earl Eutsler urges ANCs to work with project developers to achieve maximum practicable soil volumes for street trees, under-sidewalk soil, and root paths, and maximum opportunities for moisture to infiltrate to tree roots.
ANCs do not dictate or regulate. But they can advise developers, and their advice to government agencies is entitled to “great weight.”
A perfect example is the Park Van Ness project now under construction at 4455 Connecticut Avenue NW. The Saul Centers project actually pre-dates DDOT’s new standards. And in consultation with ANC 3F, Saul revised its landscape plan to do much better than even those.
“Saul would have been required to provide at least 7,500 cubic feet of soil for the six new trees if the [new] standards had been in effect,” explained UFA’s Sharon Dendy, but “Saul has exceeded the overall minimum by adding [to new tree boxes] more structural soil under the sidewalk and [root paths] connecting to adjacent planters to be installed behind the sidewalk.”
The soil volumes for the six trees in the tree boxes alone will total 10,620 cubic feet, with 1,760 cubic feet more connected by root paths. The diagram below shows the accommodations for two of those trees.
Saul’s revised plan challenges ANCs all over DC to get other developers to emulate Saul, at the very least. And ANCs have several opportunities to get involved.
This means paying particular attention to future public space permit applications from private developers, so that those projects also exceed minimum standards – by as much as Saul or more. ANC attention is similarly in order on DDOT’s own work to build, fix, or replace streets and sidewalks. Even small projects might be able to add root paths between tree boxes at the curb and private-space lawns and gardens.
With DDOT’s new standards in its toolbox, our own ANC 3F can stay in the forefront of this national shift to green infrastructure, and realize its goal of “a beautiful, sustainable, tree-shaded [Connecticut] Avenue.”