Category: Water Resources and Wetlands

A comeback

Stephen Syphax gave an interesting presentation to the Friends of Dyke Marsh on the wetlands restoration work at Anacostia Park, the first and perhaps most successful being 1993’s 32-acre (13 ha) Kenilworth Marsh project. Syphax is Chief of the Resource Management Division for NPS’s National Capital Parks-East.

Early in the previous century, the tidal lagoons along the slow-moving Anacostia River were viewed as a problem to be rectified: the McMillan Plan captioned an image of the area as “malarial flats to be excavated.” So, wetlands that were home to abundant stands of wild rice (Zizania palustris) were displaced and the river straightened by the Army Corps of Engineers to make way for a golf course, landfill, power plant, and parking lots for RFK Stadium.

Restoration work began in 1991 with pilot-project containments, with the objective of identifying the optimal ground elevation (about 2 meters) for encouraging emergent vegetation. Syphax suggests that too much height promotes the growth of Phragmites australis. Hydraulic dredging (to minimize the suspension of potentially toxic sediments) began shortly thereafter—what Syphax called the arrival of “the big yellow machines.” Novel “water tubes” (think of Godzilla’s garden hose stretched across the marsh) were used as a temporary, low-impact means of containment of dredged-up material as it settled and consolidated. Then came planting of about fifteen species of native plants, 350,000 individuals in all, along with the arrival of another dozen volunteer species—including the invasive Purple Loosestrife (Lythrum salicaria). In retrospect, Syphax says it wasn’t necessary to plant as many different species as they did. Once the plants were established, another machine cut tidal guts into the reclaimed wetland.

A happy result of the restoration work was the sighting of Marsh Wren (Cistothorus palustris) in 1996. And the jewel of the rehab is the reappearance of American Lotus (Nelumbo lutea), which opens its pale yellow blooms over the water each July.

While this phase of the restoration work was quite successful, more recent work in the Kingman Lake area has been hampered by resident populations of Canada Goose (Branta canadensis). The geese saunter over from Langston Golf Course and treat the newly-planted veg as a “salad bar,” in Syphax’s apt phrasing.

No mistake

Forty years after an attention-grabbing fire, Christopher Maag gives a progress report on the cleanup of the Cuyahoga River. We’re getting there, after $3.5 billion spent to reduce pollution, $5 billion on upgrades to the wastewater system, along with dam removals and other restoration projects.

“This didn’t happen because a bunch of wild-haired hippies protested down the street,” [John] Perrecone [manager for Great Lakes programs at the Environmental Protection Agency] said. “This happened because a lot of citizens up and down the watershed worked hard for 40 years to improve the river.”

Cool running

Jonathan Erickson’s recent newsletter post for Dr. Dobb’s highlights a couple of the low-tech water development projects of Engineers without Borders: specifically, projects to bring clean drinking water to two villages in Honduras, designed and managed by USC students Liana Ching and Jackie Reed. Their scheme rests on

…a pair of 10,000-gallon storage tank[s] with a chlorination system (via tablets) upstream, away from the pollution.

But designing a system that would work in a remote village with no electricity is no small feat. The design they eventually came up with is a self-sustaining dam and water pump that uses paddles to carry water to a tank before it gets distributed by pipes to the villages.

“The students had to learn from scratch,” says Mansour Rahimi, their advisor and an associate professor of industrial and systems engineering. “There is no software, no tables or books on this.” Dana Sherman, a senior lecturer also in the industrial and systems engineering department, added that “the project involves so much more than just designing and installing a pump system…[it also involves] implementing a system that does not require consistent or difficult maintenance.”

14 questions: 2

Thanks to the presidential campaign of John McCain for likewise responding to Sciencedebate 2008’s 14-item questionnaire. Without offering too much in the way of specifics, McCain does make it clear that he understands how complicated water issues in the West can be.

10. Water. Thirty-nine states expect some level of water shortage over the next decade, and scientific studies suggest that a majority of our water resources are at risk. What policies would you support to meet demand for water resources?

As a westerner, I understand the vital role that water plays in the development of western economies and to maintaining a high quality of life. Water is truly our lifeblood. I believe that we must develop, manage, and use our limited water supplies wisely and with a conservation ethic to ensure that we have sufficient supplies to meet municipal, tribal, industrial, agricultural, recreational, and environmental needs. I believe that water rights must be respected, and that disputes are better resolved not in the courts but through negotiations that build consensus, and provide justly for the needs of the west’s diverse interests and needs. I understand the importance of state law and local prerogatives in the allocation of water resources, and that all levels of government must work together with stakeholders to ensure that our lifeblood is protected, managed, and utilized in a wise, just, and sustainable manner.

I support constructive, continuing cooperation and dialogue among the states and the water users in a manner that is fully consistent with existing compacts and agreements. This is an approach that is forward looking, and ensures cooperation in achieving implementation of water agreements among the states and the Department of the Interior and is mindful of potential technological developments that could potentially reduce water demands in certain areas.

To rebuild a wetland

Dr. Katharina (Katia) Engelhardt of the University of Maryland spoke to the Friends of Dyke Marsh about her research at the wetland and the prospects for its restoration. Dyke Marsh constitutes about 200 hectares of tidal freshwater marsh on the west bank of the Potomac River, just south of Alexandria, Va. and the Beltway. The marsh, as a wildlife preserve, is part of the George Washington Memorial Parkway lands, administered by the National Park Service. The NPS is considering acting on long-discussed restoration and management plans for Dyke Marsh.

Over the decades, parts of the marsh have been overtaken by the river. Some of the causes are global—worldwide sea level has been rising at the rate of 3.1mm/year and the Chesapeake Bay at twice that rate—and some are, we suspect, local. A bridge over Hunting Creek, just upstream of the marsh, as well as other development and urbanization, has changed siltation patterns, perhaps starving the marsh of sediment. Dr. Engelhardt stressed that very little good erosion data were available for the area, so we don’t really know how accretion nets out against sea level changes.

Dr. Engelhardt’s research turned up a couple of surprises. Though much of the ground lies in the range of elevations from 0.3m to 0.8m, there is much bumpiness in the terrain. Tidal channels, rather than following a hierarchical flow from lower to higher orders, instead form a complex web of cross-linked flows. Her focus on the botany was limited to the emergent herbaceous vegetation. Even though tidal freshwater wetlands tend to be species-poor, nevertheless she and her research students found representatives of eleven taxa, annual and perennial, including spatter dock, wild rice, and cattails. (Invasives tend to be more prevalent in relative upland of the woods, which was not the focus of her studies.)

Three restoration scenarios were outlined:

  • Aggressive pumping and dredging to restore the marsh to its full extent from the first half of the twentieth century.
  • Partial restoration, perhaps in a shallow area below Hog Island, which was designated as a demonstration area in a 1977 study, with the possibility of further efforts.
  • Shoreline erosion control only.

Whatever we do, Dr. Engelhardt said, we must make sure that the effort is sustainable, that is, that future natural accretion is sufficient to maintain the marsh.

Not so green

Willie D. Jones reports on research (preliminary, apparently not yet published) by the Virginia Water Resources Research Center that compares various energy sources and means of power generation in their efficiency of water consumption. That certain high-tech darlings of alternative energy, like ethanol, are relative water hogs is less surprising than the wide spread of computed values, spanning four orders of magnitude. While natural gas requires only 38 liters of water per 1000 kilowatt-hours generated, biodiesel was measured at 180.9 to 969 kiloliters of water per 1000 kW-h. On the generation side, the range is from 260 l/kW-h for hydroelectricity to 31000 to 74900 l/kW-h.