Fresh policies will freshen the flow into the Washington Channel

Yesterday, I wrote about the numerous storm drains that currently dump polluted water directly into Washington Channel. The District of Columbia recently adopted some of the nation’s most stringent and innovative rainwater policies, and the Washington Channel watershed stands to significantly benefit as plans and projects adapt to these new policies and incorporate state-of-the-art practices in green infrastructure (GI). The Natural Resources Defense Council’s “Rooftops to Rivers” report give DC’s new policies a high rank (just behind Philadelphia) among their “Emerald City Criteria” for river-friendly municipal policies.

Canal Park's fountain & rain garden
The new Washington Canal Park, just a few blocks east of the Washington Channel watershed, recycles stormwater not just for its site but also for three neighboring developments.

The impetus for these changes came from the 2011 renewal of DC’s “MS4 permit,” the EPA permit for the storm drains that drain the urbanized part of the Washington Channel watershed (and 2/3 of the District), and is managed by the District Department of Environment (DDOE). As part of this process, DC has adopted a completely new set of stormwater regulations with three key innovations:

  • a DDOE impervious surface charge to generate revenue for municipal green infrastructure, encourage existing buildings to reduce impervious cover, and reward “RiverSmart” properties (this is separate from DC Water’s impervious surface charge)
  • a retention standard that requires new buildings to retain 1.2″ of rainfall on site (~90% of all rain events), and renovations to retain 0.8″ on site
  • a credit trading scheme, the first in the country, giving the retention standard flexibility for dense downtown developments, rewarding efforts that go beyond, and generating funds for comparatively inexpensive GI improvements in the neighborhoods like Canal Park. By taxing bad things, like water pollution, you create an economic incentive to create good things, like neighborhood parks. (In DC, this creates a tidy way to “tax” federal offices through utility fees, and then build neighborhood parks.)

Although DDOE expects only 1% of the city to annually be affected by the retention mandate, that’s still 10X the area currently affected each year by voluntary green infrastructure efforts.

While this change in stormwater regulations is currently only tied to the separated storm drain permit managed by DDOE, DC Water hopes that these efforts will be able to have an appreciable impact on its troublesome combined sewer system. If so, DC Water may be able to renegotiate an existing EPA mandate requiring billions of dollars in new “deep tunnel” pipes (see pg. 7 of this Brookings report).

These just-implemented policy changes are already shaping up to have a positive impact on the Washington Channel watershed, where much of the urban fabric will change in coming years.

  • The Southwest EcoDistrict, a plan currently under development (primarily by the federal National Capital Planning Commission, with ZGF Architects) for the redevelopment of several blocks of mostly federal offices centered around 10th & D Streets SW, plans a truly cutting-edge water management scheme. The overarching goal is to reduce water use by 70% even while increasing the number of people on the site. Pages 11-29 of the May 2013 PowerPoint featured on their website goes into great detail about the strategies that the EcoDistrict can employ towards that goal: treating both greywater and air conditioning condensate water for potable use, storing a 1.7″ rain event in a truly vast cistern hidden underneath an existing bridge, and (by going beyond the 1.2″ mandate) receiving stormwater credits from other developments.
  • Over half of the Washington Channel’s urban frontage (over six blocks) is included within plans for the Wharf, a proposal to completely transform the Channel’s shoreline. The development embraces the Channel with a new riverwalk and several public piers that will bring the public down to the Channel’s water — very different than today’s gated-marina frontage. Complying with DC’s 1.2″ retention standard earns the Wharf the maximum number of LEED-ND points possible under the stormwater management credit, helping it achieve its LEED-ND Gold rating. Among the innovative strategies planned: using stormwater as process water within an on-site combined heat & power (cogeneration) facility that improves both energy efficiency and reliability.
  • Recent construction underneath the National Mall, part of which is within the Tidal Basin watershed, not only rebuilt the severely compacted turf but also included 500,000 gallons of rainwater storage in two cisterns — probably the city’s largest such installation. The Park Service plans another two cisterns as part of further Mall turf renovation, to store water running off the Mall (no, compacted turf doesn’t really do a great job of absorbing rain) and its drives for future irrigation uses. These cisterns could be just the start: in 2011, NCPC studied a two-block-long cistern, the entire width of the Mall, to store 20,000,000 gallons — enough to handle a 100-year rain event, and hopefully prevent the Federal Triangle from flooding again.
  • Stormwater fees are also having an impact on a smaller scale. My own apartment building near the Washington Channel, built during the concrete-happy 1960s, has just embarked upon an aggressive program to replace paved surfaces — open roof, impermeable walkways and driveways — with green or permeable surfaces. This long-overdue plan was put into motion due to the new impervious surface charge.

In the future, big storms like tonight’s (but not quite so big) might actually improve the Washington Channel’s water quality, instead of harm it. Later: a look at the Washington Channel’s water chemistry, plus what that means for future evaluation of the channel. But tomorrow, I’ll look at how the physical form of the Channel shapes habitats along, and within it.


This semester, I’m taking a Natural Resources class through Virginia Tech about understanding local watersheds, wherein I’ll be researching and posting knowledge about the Washington Channel. You can explore the other watersheds that my classmates are investigating over at the class blog’s page. Other posts in this series can be found using the tag watershed.

The rain falls upon this plain, but then what?

Washington Monument in a different reflecting pool

As I mentioned in previous posts, the Washington Channel is quite unique in that the water contained within it has little to do with its drainage basin: instead, its water is essentially imported from downstream via the tidal cycle. As such, its water quality (unlike almost all other waterways) largely does not reflect the land and water context adjacent to it. In addition, the Channel benefits from being entirely within the District of Columbia: the federal government has long held title over the waters (Morris vs. United States), and used parkland to create and frame the Basin and Channel. As a result of that unique context, not only does parkland surround all of the Tidal Basin and most of the Washington Channel, but the surface waters are also under federal protection.

Tidal Basin & Washington Channel hydrological maps

The Tidal Basin and Washington Channel do receive surface and groundwater runoff from their immediate areas, which together add up to 1.412 square miles of the District. The Tidal Basin drains 0.423 sq. mi., of which 0.169 sq. mi. (almost 40%) is surface water. 43% of the watershed is parklands and grass areas, including parts of the National Mall, the monuments ringing the Basin, and even the small hill underneath the Washington Monument.

Tidal Basin & Washington Channel hydrological maps

The Washington Channel drains 0.989 sq. mi., of which 0.3 sq. mi. (25%) is surface water. As its north bank is heavily developed, 53% of its watershed includes urban development, and the remaining 22% is parkland.

DC’s largest water pollution problem is its combined sewer/stormwater system, or “CSO.” (I’ll write more on these systems in later posts; they’re super-important for understanding urban water quality but not entirely relevant to this post.) This system, which is responsible for dumping a toxic brew of sewage and rainwater directly into many local waterways, drains one-third of the city, including most areas built before World War 2. However, since the immediate environs of the Tidal Basin and Washington Channel were redeveloped in a somewhat recent era, they have separate sewer and stormwater systems. This map shows the large parts of the city which have combined sewers — many of which, incidentally, are named after the creeks that they replaced:

Instead, smaller, separated storm drain systems — nine along the Channel and three along the Basin, delineated by the faint lines running roughly perpendicular to the water on the map below — intercept rainwater that falls on Southwest Washington’s roofs and streets, and dumps that untreated water into either the Tidal Basin (light blue on this map) or the Washington Channel (tan on this map):

Tidal Basin & Washington Channel hydrological maps

As you can see by comparing the first and last maps, the inland boundaries of the two watersheds are defined by these artificial drainages rather than the natural contour lines seen in the first map. If you look in the vicinity of N and O Streets SW, for instance, you’ll see that there’s a valley roughly between Third Street and Half Street. Historic maps show this as what was James Creek, which drained pretty much due south to the Anacostia River, but instead these blocks now drain “uphill” to the Potomac to the west.

The storm drains dump unfiltered water, often contaminated with urban pollutants, directly into the Basin and Channel. This contributes substantially to the substantial water quality problems within these two water bodies, but plans are underway to substantially reduce the quantity of these flows in the near future.

Sources for this post, notably the maps and geographic analysis of watersheds, include the DC Department of Environment’s water quality standards documents, which I’ll report on in greater detail in an upcoming post.


This semester, I’m taking a Natural Resources class through Virginia Tech about understanding local watersheds, wherein I’ll be researching and posting knowledge about the Washington Channel. You can explore the other watersheds that my classmates are investigating over at the class blog’s page. Other posts in this series can be found using the tag watershed.

One vision for a Southwest DC that could have been

Arthur Goodwillie’s proposal for retaining the rowhouse fabric and infilling block interiors with courtyard apartments was rejected, not really due to cost but primarily due to complexity. Instead, the federal government built garden apartments in places like Arlington (WAMU story; NR nomination [PDF])

Goodwillie Plan for SW: contrast existing and proposed

[More images: closer look at redevelopment scheme | closer look at existing conditions survey | existing structures for entire Southwest neighborhood | historical material about the Capitol Park redevelopment project subsequently built on the site in question, courtesy CP II Condominium Association]

The following excerpts are from “The rehabilitation of Southwest Washington as a war housing measure : a memorandum to the Federal Home Loan Bank Board,” by Arthur Goodwillie, January 2, 1942 [LOC catalog record], a never-implemented plan for selective demolition and infill in the area subsequently cleared and redeveloped as Capitol Park. For further background, I recommend Christian James’ website about the redevelopment and Studio 27′s presentation (& book).

(Pg. 7.) The war effort should be so organized as to avoid unnecessary damage to the important peace-time values which in part — it must be remembered — we are seeking to defend. If it can be carried forward so that subordinate but highly important economic and social values will also flow from it — as by-products — then failure so to develop it is both shortsighted and indefensible.

The production of standard war housing in areas where only obsolete structures and vacant city lots now exist, as recommended in this memorandum, will also (a) eliminate — without direct cost — large slum and blighted areas; (b) restore value to much substandard Class “B” residential real estate; (c) lessen the post-war impact of new war housing on Class “B” property value and mortgage security; (d) reduce the volume of uneconomic suburban development and the costly duplication of schools, streets, utilities, etc.; (e) help stabilize the declining municipal tax base and put to productive use much unproductive, municipally owned real estate, acquired through the enforcement of tax liens; (f) provide local housing authorities with many units to offer as “equivalent elimination”; and (g) set up a large reserve of standard but low cost housing, for post-war rental to low income families, at rent levels that will reflect little or no subsidy.

(Pg. 16-19.) The population is relatively stable. A study made some years ago among white residents of Southwest Washington developed the fact that of the 10,658 persons interviewed, 9981 wanted to continue living there. The recently completed nine block Bank Board survey, on which the following report is based, showed that about 80% of the negro population has lived in the district for 5 or more years.

Present construction within the Area consists largely of two story, brick, row houses, two and three rooms deep, among which is interspersed a smaller number of frame structures of the same general type.

HOUSING PROBLEM
Although it extends to within three blocks of the Capitol of the United States, structural, economic and social conditions in the Area are shameful. Though basically sound, the brick structures of the post Civil War period are almost uniformly substandard… Interspersed among these brick dwellings is a considerable number of older frame houses. The latter are in a lamentable state of repair, dangerous, unhealthful, vermin and rat infested. They constitute a serious fire, safety and health hazard and should be demolished, as a slum clearance measure, at an early date.

Block interiors contain over 300 substandard alley dwellings, or are used as storage spaces for the miscellaneous accumulations of an indigent population. Moral and health conditions in many of these insanitary, unheated houses are deplorable. Fortunately, their use for residential purposes after 1944 is prohibited by law.

The Area, however, has many valuable assets. Were modern housing available, it would be an ideal residential location for the tens of thousands of persons who are employed in adjacent governmental Establishments, Departments and Agencies.

Streets are wide and well shaded. Water, light and sewer mains, sidewalks and pavements are in place, paid for and well maintained. Side by side with decrepit frame structures are some 2900 substandard but basically sound brick buildings, usually in rows, virtually all of which can be saved and are well worth saving. Vacant perimeter lots, vacant block interiors and land on which now stand decrepit frame structures, which should be demolished as a slum clearance measure, provide sites for an additional 5000 dwelling units. This is a total of about 8000 units for the Area, without over-crowding.*

Block interiors are unusually large and offer a unique opportunity for development as open green commons and play spaces, abutting on the new construction referred to above. Along the entire western margin of Southwest Washington is the recently developed Washington Channel waterfront. [Adequate schools, settlement houses, and churches.]

An exceedingly difficult questions which now confronts most established residential communities — whether they are depressed or not — is how to supply necessary large additions to available neighborhood recreation spaces. Adequate park provisions is not a problem in Southwest Washington, since the “Canal Reservation,” a public park which will provide ample playground facilities for the adjacent residential section, lies along the entire eastern border of the Area. Because it occupies a wedge-shaped tract between the Pennsylvania Railroad and Washington Channel, through traffic problems are also virtually non-existent.

The statement that there is a dangerously increasing housing shortage in Washington will be accepted without debate…

Pg. 53. The considerable saving in site cost [due to the low cost of land in Project block interiors] has all been allocated to new construction. If, as seems equitable, it were prorated between (a) the cost of projected new dwelling units and (b) the cost of rehabilitated units — the the over-all cost for reconditioned structures would be reduced to $725 per room** or to about 54% of that for new construction in similar areas elsewhere.

* In 2000, the Census counted 7,487 dwelling units in a comparable area, post-redevelopment, although with more office employment areas.
** emphasis in original

N & Union Streets

Mud becomes concrete: Washington Channel’s history, told through maps

This semester, I’m taking a Natural Resources class through Virginia Tech about understanding local watersheds, wherein I’ll be researching and posting knowledge about the Washington Channel. You can explore the other watersheds that my classmates are investigating over at the class blog’s page.

In this installment, I’ll take a closer look at how the channel came to be a (sort of) discrete watercourse, to provide some context for later posts about today’s land and water quality. Other posts can be found using the tag watershed.

From Montreal to Providence to Trenton to Richmond, many of the East Coast’s great cities arose astride the “fall line,” an imaginary line along which its many rivers tumble from shallow rapids in the hills to slow, wide, sometimes brackish coastal estuaries. In an ocean-going era, such a location ensured easy access for oceangoing commercial boats, fresh river water, produce from farms upriver and fisheries downriver, and later to water power from the rapids or waterfalls alongside — all without the considerable downside of a coastal location’s vulnerability to frequent Atlantic storms.

Spillway
[Minneapolis, built astride the falls of the Mississippi, could be considered the most interior of the East Coast's fall line cities.]

Washington, D.C. is among these fall line cities, and its constant attempts to reshape the Potomac River’s banks also show the vulnerabilities that fall line geology also brings. Above Washington, the Potomac speeds through a narrow gorge, tumbling over its majestic Great Falls and past the high bluffs of wealthy towns like McLean, Potomac, and Georgetown. At Washington, three flows of water conjoin: the slower and broader Potomac, Atlantic seawater that tides pull all the way up the Chesapeake Bay and the Potomac estuary (with tides rising to 3.5′), and several surface flows. The comparatively flat topography of the L’Enfant City results from it resting upon a “shelf” of sediment brought there by the Potomac over time. This 1861 bird’s-eye view map by John Bachmann (from the Boston Public Library collection) plays up the topography, dramatically showing how the character of the Potomac valley changes at Washington:

Bird's eye view of part of Maryland, Distr of Columbia and part of Virginia

Several surface flows join the Potomac at Washington, notably the Anacostia River, Rock Creek, and Four Mile Run, but also several streams that have since been buried like Tiber Creek and James Creek. (David Ramos has compiled an impressive map of these buried streams.) From the very beginning of the city in 1790, plans were made to tame these streams for human uses like shipping. A map from the 1790s, drawn by John Russell, shows how city fathers, Pierre L’Enfant among them, conceived a system of drainage improvements. These canals were straightened channels based upon the east-west Tiber Creek and the north-south James Creek, both arising roughly where Garfield Park is today at the foot of the Capitol. The map also shows the outlines of the deeper, more easily navigable channels within the mostly shallow Potomac:

Plan of the city of Washington[...]

This idealized 1852 view, published by E. Sachse, illustrates the canals in an improbable shade of blue:

Shortly after Washington was founded, the Potomac’s plentiful sediment became a problem for the growing city. Land clearance for forestry and farming upriver combined with increasing levels of urban pollution dumped into local surface waters, making the water noxiously polluted — particularly during low tide, when pollution festered in exposed tidal marshes. The insalubrious tidal marshes at the mouth of Tiber Creek, beginning at the foot of the White House, appear to have given rise to the widespread myth that “Washington was built on a swamp.” The marshes are visible in these digital reconstructions of the 1791 shoreline:

Then and now: Washington Channel

Original and present shorelines of Potomac Park

The sediment buildup also threatened the city’s access to maritime trade. Given the marshes along the Tiber, the new city’s only shoreline adjacent to a deepwater channel within the Potomac was along its southwest waterfront. Wharves sprang up along Maine Ave. SW, landing fish and ferries that went to Alexandria and points beyond. In this process, this shore gradually urbanized and gained a “coat of armor” as buildings crept up to the water’s edge, as shown in this 1883 drawing by A. Sachse:

Private property owners’ interventions to shape the shoreline would soon be dwarfed by Congressional plans, particularly as the sediment threatened the relatively deep channel fronting Southwest’s wharves. Engineers (notably Peter Conover Hains) from what would become the Army Corps saw an opportunity to tame the city’s shoreline, preventing severe floods like that of 1881 from reaching the city’s core. Meanwhile, planners saw the potential for new parks — simultaneously adding land to the capital of a fast-industrializing country, meeting a post-Civil War national zeal for commemorative monuments, and providing Washington with a vast expanse of parks at its doorstep (as the fin-de-siecle era’s vogue the City Beautiful demanded).

This 1888 map by E. Kurtz Johnson depicts an early “cloverleaf” plan by Hains for filling in much of the Tidal Basin area, leaving a series of small pools that would be used to flush a new Washington Channel downstream:

In 1901, the City Beautiful reached its apogee here in Washington with the McMillan Plan. Shortly thereafter, the canonical birds-eye view of Washington had shifted 270 degrees; instead of placing the Capitol dome front and center with the filthy Potomac River in the distance, now bird’s-eye views proudly showed off the carefully sculpted shoreline, with its large and scenic Tidal Basin, an urban shoreline for the Washington Channel, and probably many more trees in Potomac Park than existed at the time (1916, drawn by H. H. Green):

Many of these maps courtesy of the Historic Print & Map Company, via DC Vote’s archive of Washington, DC, Historical Maps; high-res PDF versions can be downloaded there. Others were drawn from a Washington Post Magazine feature by Scott W. Berg, featuring mapping work done by architect Don Hawkins and Dan Bailey/UMBC Imaging Research Center.

Southwest Washington: introduction

This school year, I’m working on a series of projects relating to my neighborhood of Southwest Waterfront. Since this semester’s work is with a team of other students less familiar with the neighborhood, I’ll be posting resources about the neighborhood on a periodic basis, which you can easily find using the swdc tag.

Walk through Southwest Waterfront

A few months ago, I gave a short presentation to CNU-DC based on a summertime walk around the neighborhood. Note that this covers only the Waterfront residential neighborhood, not the Southwest Rectangle (Federal Center & L’Enfant Plaza) office precinct north of I-395. You can download the PowerPoint or take a look at the photos on Flickr.

There are also a lot of great, easy-to-use online resources. I particularly like:

An extensive collection of original documents related to urban renewal in Washington can be found at the Washingtoniana Collection, on the third floor of the MLK Library at Gallery Place.