sign in sign up
<<
Home , Mattawoman Creek, Piscataway Creek, Potomac River

Potomac Basin

Vol. 63, No. 5 Interstate Commission on the Potomac Basin Sept./Oct. 2007

C. Dalpra Diverse beds of aquatic plants have flourished in the upper tidal Potomac in the last few decades, providing many benefits.

A River of Grass (and Some Invasive Plants) The U.S. Geological Survey (USGS) time in the river, water lettuce (Pistia boat eased out onto the Potomac from stratiotes), which could pose a serious new Gunston Cove to spend another day impact. checking on the status of the numerous The day-long cruise was one of a series beds of submerged aquatic vegetation of trips that Rybicki makes each summer (SAV) hugging the shoreline of the tidal and fall since the early 1980s, creating a fresh portion of the river. detailed account of the emergence and The sunny September day found growth of SAV on the tidal freshwater USGS aquatic biologist Nancy Rybicki Potomac. For more than a decade before checking out the shoreline from that, the area was devoid of SAV, Rybicki , about 10 miles from noted, brought on by increasing pollution Washington, D.C., downstream and into and massive, persistent algal blooms. A Creek, one of the most detailed assessment of the area’s SAV productive in the tidal Potomac. resurgence coauthored by Rybicki is The stretch is just a part of the region she available on the web at http://aslo.org/lo/toc/ studies, on both sides of the river from vol_52/issue_3/1195.pdf. Washington, D.C., downstream to Today, things are much different, with where the river makes a extensive stands of mixed species of plants big turn toward the northeast. hugging the river’s shoreline. “It’s been a The cruise was notable for confirming very good year,” for the growth of SAV in the both the health of aquatic grasses in the tidal freshwater Potomac, Rybicki said. upper tidal Potomac, and the presence of “Coverage is as high as any year [since a new invasive species found for the first plants returned to the river], and the

431112.pmd 1 10/29/2007, 1:59 PM diversity of species is high in many places,” Rybicki said. The resurgence of SAV in Our mission is to portions of the Potomac has been one of enhance, protect and the “good news” stories for the river for the last quarter-century. Increasing stands of conserve the water and SAV have helped to clear murky water, associated land decrease nutrients in the water that cause algae blooms (see July/August 2007 resources of the Reporter), serve as a food source for a variety of organisms, and provide for and its fish and other creatures on which they prey. tributaries through As the boat nosed over to the Maryland shoreline, the beds were indeed regional and interstate impressive, with some stands stretching more than the length of a football field into cooperation. the morning haze. Hydrilla (Hydrilla verticillata), an invasive plant that was one of the first to appear in the river’s resurgence of plants in 1981, remains a ICPRB major species on the river. The improving COMMISSIONERS river conditions allowed another 11 species to quickly establish. Another foreign plant, Eurasian watermilfoil (Myriophyllum DISTRICT OF COLUMBIA: Hamid spicatum), is a major presence, joined by Karimi,* Anne D. Snodgrass, Alternate; natives such as wild celery (Vallisneria Lloyd Preslar; John R. Wennersten, americana), coontail (Ceratophyllum Alternate demersum), waterweed (Elodea canadensis), and water stargrass MARYLAND: Gov. Martin O’Malley, (Heteranthera dubia). Other species appear Robert M. Summers,* Alternate; James less frequently. The large stands generally H. Gilford, Minny Pohlmann, Alternate; occupy a shallow swath of riverbed from near the shoreline out into the river more : John T. Hines,* Lori than 50 yards, where sunlight penetration Mohr, Alternate; Rep. Dan Moul, Rep. allows for strong growth. Bob Bastian, Alternate; Ronald Stanley, The survey method is fairly direct: Motor Roger C. Steele, Alternate slowly into the bed, the boat moving in a semi-circle deep into the bed toward shore : Walter Alcorn; Del. Joe T. and back out again. Rybicki pulls samples May; David K. Paylor, Scott W. Kudlas, out with a metal garden rake, checking for Alternate; the different species present, and transferring data on species makeup and : Marten R. Jenkins, Jr., bed size onto a map. Once out of the bed, Phyllis M. Cole, Alternate; Del. Harold K. the process stops to clear the matted Michael; Stephanie R. Timmermeyer, outboard motor propeller before moving William D. Brannon,* Alternate; down the shoreline. The short trips into the grass beds are : J. Winston Porter,* amazing, lending a view of what the river Frederick R. Eames, Alternate; George generally might have looked like centuries Reiger, Mel M. Baughman, Alternate; earlier (except for the different species Jane G. Witheridge, Howard Graeffe, composition). Out in the channel, the river Alternate water is its usual summertime green from the single-cell algae that limits visibility to a couple of feet. After penetrating the beds, *Executive Committee Member the view from the boat is startlingly different. Stands of lush plants rise from the river bed to the surface. Empty pockets between ICPRB Officers: bunches of plants allow a view through gin- Robert M. Summers, Chairman clear water to the bottom, three feet or more John T. Hines, Vice Chairman below. Small fish can be clearly seen as Joseph K. Hoffman, Executive Director they dart about in the cover that means Robert L. Bolle, General Counsel safety from predators, and a source of food in the many other small creatures that call the beds home. The view is not unlike that Commissioners and their alternates are of a well-kept aquarium. appointed by the state’s governors, the The expansion of about a dozen species mayor of the District of Columbia, and the of SAV in the upper tidal Potomac has come President of the United States. on the heels of improved , primarily from improved wastewater

431112.pmd 2 10/29/2007, 1:59 PM suggested dosing the open river with herbicides. As the plant grew strongly, boaters began calling for action as propellers fouled and engines overheated. But the feared hydrilla monoculture never occurred. Instead, the plant helped to create conditions that supported the growth of other species. In effect, the beds create and support small that

C. Dalpra seem totally different Nancy Rybicki checks on SAV beds south of Piscataway Bay. from the open water a short distance away. The beds of plants trap sediment, clearing treatment in the metropolitan area that the water and opening up new territory reduced loads of nitrogen and phosphorus. where sunlight can penetrate and the plants The nutrient reductions helped to abate can grow. The SAV also use some of the the annual large algae blooms, increasing excess nutrients that feed the growth of water clarity and creating habitat that green-water algae. allowed plant beds to establish. Continued The survey proceeded through about 10 growth of the plant beds filters more silt and nautical miles of shoreline, sampling the nutrients, cascading the creation of suitable large beds, and up into . plant habitat. Grass beds are thick in the creek, one of the While the river’s strong improvement led river’s most-productive tributaries and a to the reestablishment of the aquatic plants focal point for many tournaments. in the area in 1981, the environment that Rybicki was especially interested in a stand supports that community still is fragile. In of the relatively rare American Lotus that addition to general water quality, plant had been reported some distance up the populations also are affected by high river creek. flows that can physically scour the beds as As the boat ducked into several large well as dump huge loads of silt and beds of mixed plants, a few stood out both for their bright color and their height above the water’s surface, looking like they didn’t belong. They didn’t. The plant, not seen before in the Potomac, was water lettuce, a plant commonly found in many backyard ponds and sold widely by the aquatic gardening industry. The invasive plant could create real problems in the river, if it becomes established. Rybicki was worried about this newcomer, and for good reason (see related story). The plants likely entered the river after being discarded by someone C. Dalpra whose pond became overgrown, were Water lettuce harvested by Rybicki’s rake. washed into the river from a pond or other facility, or came off a visiting boater’s trailer. nutrients that fuel algae growth and rob The small batch of the floating plants was plants of the sunlight needed for retrieved by Rybicki with her rake. After photosynthesis. traveling a short distance, another stand The non-native plants hydrilla and was found and removed. And then another. milfoil are the dominant species in the And another. It quickly became obvious that upper tidal Potomac although the others this small effort would do little good in the are firmly established, and the beds great scheme of things. The invasive plant observed usually contain three or more programs at USGS and the Maryland species. When hydrilla began establishing Department of Natural Resources were itself in the river in the early 1980s, there notified of the discovery. were concerns that it would crowd the river Overall, a visit to the upper tidal and out-compete any native plants. At the Potomac’s “gardens” is an uplifting time, an emergency committee established experience, especially to anyone familiar by ICPRB heard from some experts who with the area when plants were not to be

431112.pmd 3 10/29/2007, 1:59 PM found. The return of SAV is helping to cleanse the river, and the benefits are apparent to the large numbers of anglers who focus their fish-catching efforts on the productive grass beds. As the boat was being put away at Gunston Cove, the day ended with a chance meeting with a group of researchers from University, also focused on the grass beds. Led by Assistant Professor of Fish Ecology Richard Kraus, the team is probing the beds to assess how they have affected fish C. Dalpra populations and other living resources. Grass beds can bring frequent propulsion problems. While not ready to scientifically quantify what’s happening, Kraus noted that he is finding high concentrations of various fish Potomac, which as far as plants are species using the beds. Sunfish and concerned is a different kind of river. smaller residents like killifish, a major prey Downstream of the Route 301 Bridge at species for many larger fish, are present in Morgantown, Md., the river is much larger, high concentrations. The crew also is has higher , and is home to different, interested in large snails that are thick in more salt-tolerant species. Gunston Cove, and likely present in other Eelgrass in the lower Potomac has areas of the river. Japanese mystery snails suffered the same fate as other are another foreign transplant in the river tributaries, where silt and that use the beds. It is unknown how the nutrient loadings have caused die-backs species got in the river, but they also could exacerbated by increasing water have come from the pond trade, sold as temperature. Rybicki, with history as a trapdoor snails. The snails feed on rotting guide, said that “Once they [plants] are material and phytoplankton, and don’t gone, it’s much harder to bring them back,” consume the plants. Not much is known because a number of conditions must all about them, or effects they may have on the occur together. Seeds or propagules must complicated, intricate system that is the be present to take advantage of the right biology of the Potomac. Their young may be temperature, salinity, and sunlight, and preyed upon by crayfish, including the rusty other water quality conditions needed to crayfish, another foreign invasive species support the plants. Strong water quality that is becoming more common in the efforts could someday bring a blooming Potomac. renaissance to that portion of the river in the Unfortunately, the success of SAV in the future. upper tidal Potomac is fragile, and beds Editor’s note: Nancy Rybicki reported could decrease if water quality is allowed to finding numerous other bunches of water slip. The success in this section of the river lettuce throughout the area since the earlier has not yet flowed downstream to the lower trip.

Keep Water Lettuce and Other Invasives Out of the Potomac!

The sighting of water lettuce (Pistia stratiotes) is an alarming revelation to anyone familiar with the plant, including many aquatic gardeners. As a landscaping feature, ponds are growing rapidly, and water lettuce and water hyacinth are readily available at most stores that sell pond plants. What isn’t apparent at many stores are strong warnings about containing these plants (and fish) in ponds and ensuring they are not released to the environment. Water lettuce and other plants and animals not native to the river also can be carried by boat trailers or by floods that carry new species into the river from commercial or C. Dalpra A single floating water lettuce quickly colonize an private ponds. area, creating a dense floating mat in a few weeks. Whether water lettuce, a tropical plant, can get a foothold in the river permanently to die back at water temperatures much is unknown. In area ponds, the plant starts below 60 F. However, the plant does

431112.pmd 4 10/29/2007, 1:59 PM produce seeds that fall to the river bed, and lower dissolved oxygen levels by covering could produce plants in the spring. the water surface; crowd out other surface In area ponds, a gardener need only buy plants and kill off SAV by reducing sunlight; one or two of the floating plants. The plant restrict water flow and increase flooding; produces seeds, but spreads rapidly by provide an ideal breeding environment for sending out runners (stolens) where new mosquitoes; and hamper boating and leaf clusters quickly form. Under optimal fishing. conditions, the plants can double their Water lettuce is just the latest new number in just a few weeks, and over a species found in the Potomac, joining summer, will take over a pond without several other aquatic plants, regular harvesting. fish, the rusty crayfish, Japanese mystery The plants have the potential to take snail, and others. over coves in the Potomac. The attractive Stewardship is key to limiting these plants float on the surface, and extend long introductions, through keeping foreign root structures more than a foot into the plants or animals from entering the river. water. The plants form dense mats that can: Natural resources agencies in the Potomac basin note that introduction of foreign species is a growing problem, and urge people to: *Dispose of plants properly; *Do not put unwanted plants or animals in local waterways; *Check and clean boat trailers and other equipment used in angling, diving, or boating: *Do not dump live bait; *Do not transport bilge, live-well, or other water from one area to another.

Rusty Crayfish Move into

Watching the River Flow The rusty crayfish (Orconectes rusticus) Potomac River flows, measured near is the latest in a string of non-native Washington, D.C., were low in late invaders, including hydrilla, snakeheads, summer, continuing a steep decline in and water lettuce (see related article), now the early fall, according to provisional found in the Potomac watershed. data provided by the U.S. Geological The crayfish hail from the Survey. basin, but have spread to the Great Lakes August Potomac River flow averaged area and the northeast U.S., including about 2.10 billion gallons per day (bgd), southern Pennsylvania, where they have or about 61.5 percent of the long-term also become a nuisance, and even into average. River flow ranged from a low of parts of Canada. The rusty crayfish has about 1.24 bgd on August 19 to a high of eliminated native crayfish in Wisconsin and about 5.57 bgd on August 24. Water consumed aquatic vegetation and fish eggs withdrawn from the Potomac for in the upper midwest region’s lakes. metropolitan area According to the Federal Aquatic Nuisance averaged about 400 million gallons per Species Task Force website, the rusty day (mgd). crayfish has been reported as an invader in September low flows were more many waterways since the 1930s. severe, running at about 1.40 bgd, or Rusty crayfish were first identified in the only 38.2 percent of the long-term Potomac watershed in June 2007 during a average. Daily extremes ranged from a Maryland Biological Stream Survey (MBSS) high of about 2.00 bgd on September 1 in Marsh Creek, a to the Monocacy to a low of about 1.00 bgd on September River. Since that initial survey, the crayfish 27. Water withdrawn from the river for also have been found in the mainstem water supply again averaged about 300 Monocacy River. Maryland Department of mgd. Natural Resources (DNR) Biologist Jay Although releases of stored water Killian said, “The crayfish have been in have not been needed to date, Pennsylvania, just north of the Monocacy continuation of the drought conditions River for a while. It was not unexpected to through the winter and spring could find them in Maryland.” Killian said his trigger active management of the river group is monitoring this month to find the for water supply next summer. extent of the crayfish and track its spread. The rusty crayfish out-compete native

431112.pmd 5 10/29/2007, 1:59 PM crayfish for the best habitat, devouring the river. Their first site yielded 800 rusty submerged vegetation, fish eggs, crayfish. The only other species present macroinvertebrates, and any other food were virile crayfish (Orconectes virilis), sources in their path. They can reduce the another non-native invasive species that number of species of plants, has made Potomac waterways its home. macroinvertebrates, and fish quickly. Rusty As of now, there is no control or crayfish are less likely to succumb to eradication for the crayfish. It is suspected predators when young, as many native that the crayfish was transported to the crayfish are, because they grow so fast. In watershed by fishermen using them for bait. turn, the rusty crayfish will eat fish egg The DNR is working on gathering the masses and the lack of submerged baseline data to assess the impact of this vegetation leaves young fish that do survive invasive species. Fishermen can be on the more vulnerable to predators. lookout for the invader by checking for Killian indicated that the group samples small rusty-colored patches on the sides of 75 meters of river at each of 21 sites they the crayfish. If you have questions about are reviewing in the Monocacy watershed rusty crayfish, contact DNR at (410) 260- from the Mason-Dixon line to the mouth of 8610.

ICPRB Uses Drought Conditions to Study Water Supply

The very dry conditions during the The cooperative water supply system, summer and fall have caused serious the product of decades of research and problems for some in the Potomac basin, refinement, has kept the region from with farmers in some areas losing crops, needing to implement water restrictions and shortages in some when the flow of the Potomac can’t meet communities that rely on small or demands while leaving enough water in the groundwater in areas where the water table river to protect its ecology. “The billions of has been dropping. These conditions also gallons of water stored in the have brought renewed media interest in the serves as a ‘bank account’ for the region’s status of drinking water systems throughout water supply,” explained CO-OP Operations the region. Director Erik Hagen. “As with any savings For the Washington metropolitan area account, we want to keep it full so that it is water suppliers and the ICPRB Section for available when it’s needed most,” he said. Cooperative Water Supply Operations on The tests increase the system’s the Potomac (CO-OP), the extended dry efficiency by increasing understanding of period has led to added responsibilities how long it takes for released water to get and opportunities. The organizations have to the intakes, about nine days under increased flow monitoring of the Potomac previously tested conditions. With better River, prepared for the possibility of knowledge of how the system responds, augmenting Potomac flow to meet the managers can release just the amount drinking water demands, and using these needed to satisfy water demands and low-flow conditions to learn how to more- environmental needs, leaving the rest for efficiently operate the reservoirs that serve use later. Time-of-travel can vary depending as a “savings account” to ensure that the on the amount of water released, and the metropolitan area’s drinking water background flow condition of the river. demands can be safely met even in the Generally, higher background flows or worst of droughts. release rates decrease travel time. “These In October, CO-OP staff took advantage tests can show us how to release less water of very low Potomac River flows and a rain- than called for under current operating less forecast to conduct time-of-travel tests rules, and still meet the targets,” said in the river. The small releases of stored Hagen. One of the test releases arrived in water from the Jennings Randolph about seven days, Hagen added. Further Reservoir were monitored to assess the testing can help hone the operating rules time needed for water to travel some 200 for greater efficiency. “The information we miles down the river to the metropolitan can gain from these tests could inform area water intakes for the three major water management for decades,” Hagen said. suppliers, Fairfax Water, Washington As this newsletter goes to press, the CO- Aqueduct, and the Washington Suburban OP staff are closely monitoring river levels, Sanitary Commission. Collectively, the precipitation forecasts, actual and forecast suppliers serve more than 4.1-million demands from the water suppliers, and residents of the area. groundwater levels in the basin. The data is

431112.pmd 6 10/29/2007, 1:59 PM used as important information in the status.htm. process that guides the timing and size of The U.S. Geological Survey has noted potential water supply releases. As the that groundwater levels, which were normal region continues under a drought, the or above normal earlier in the summer, are likelihood of actual releases increases, and continuing to drop and some are now could occur this fall. Annual testing of the reaching very low levels. A winter with system through drought simulations and normal precipitation would allow periodic assessments of future demand groundwater recharge, which will make leave area water managers confident that and streams more resistant to periods the metropolitan area will have enough of low rainfall. Some streams in the water, even during a drought worse than watershed have hit historic lows, although any in recorded history. the mainstem Potomac remains far from a Any releases this year likely would be new record. small, but if drought conditions continue The efforts of CO-OP and the water through the winter, releases could be more suppliers focus on meeting the drinking common next summer and fall. The fall and water demands of the residents of the winter traditionally is a time when reservoirs region. At the same time, everyone is refill and groundwater tables, which provide encouraged to be a part of conserving our the base flow for the area’s streams and valuable water resources, whether the rivers, recharge. More information about source is a water supplier or a private well. how the metropolitan water supply works There are many ways to conserve water and updates on its status are available at year-round. To learn more, visit www.potomacriver.org/water_supply/ www.wisewateruse.com.

Students Meet River Residents

ICPRB staffer Jim Cummins shows students the kinds of bugs that can be caught in the river and used to help determine water quality. The collection of live critters were part of a World Water Monitoring Day event held in Alexandria, Va., on September 18. More information on the international event, sponsored by the Water Environment Federation and International Water Association, can be found at www.worldwatermonitoringday.org.

C. Dalpra

Catoctin Aqueduct to be Restored

The National Park Service’s aqueducts along the C&O Towpath, Chesapeake and Ohio Canal (C&O) staff all in varying conditions. The Catoctin have begun organizing the large stones to Aqueduct was completed in 1834 and saw be used for restoring the Catoctin Aqueduct its last canal boat in the 1920s. In preparing over Catoctin Creek near Lock 29 in for the restoration, C & O Canal Park staff Lander, Md. The aqueduct featured a retrieved some stones from the creek, but unique elliptical center , which sagged many were found in the aqueduct prism and eventually failed in 1973. John Noel, where they had been collected after the the park’s partnerships coordinator said the collapse. The find will allow reuse of about restored aqueduct will “maintain historic 300 of the original stones from the integrity, but improve internal infrastructure aqueduct. With the recently restored Lander by using concrete instead of fill.” Noel also Lockhouse and the newly restored Monocacy indicated the restored aqueduct would Aqueduct, the area will certainly bring maintain its elliptical center arch. history back to life for park visitors. The Catoctin Aqueduct is one of 11 The total cost for the project is $3.4

431112.pmd 7 10/29/2007, 1:59 PM million. Half of the restoration funds will The project still needs about $220,000 to come from Maryland’s Transportation move forward with the plan. To donate to the Enhancement Program and the remaining project or for more information, contact Dr. half has been or will be raised through George Lewis of the Lander Community donations. The Lander Community Association at [email protected] or visit Association has been a driving force the Aqueduct Restoration website at behind the restoration and fundraising www.catoctinaqueduct.org for more efforts for the aqueduct and was the force information. behind the Lander Lockhouse restoration.

Too Much Paper? Swimming Returns to D.C. For those whose mailbox gets just It was just a temporary return, however, too full, remember that you can read the for participants in the Nation’s Triathlon, Potomac Basin Reporter on our web site held in the District on September 29. The after getting notified of new issues by swimming part of the triathlon was email. You may request an email cancelled in the previous year’s inaugural subscription on our website, or send us race, rains just before the race raised a note at [email protected]. levels in the river above Readers who are moving can help guidelines. Race founder Charles Brodsky ICPRB save some money by letting us hired a laboratory to test the river frequently know of your new mail or email address. before both events. For mail subscribers, please send a This year, the monitoring convinced note with your current and new mailing officials that the swim part of the race could addresses. Thanks for helping us keep proceed, and temporarily lifted the ban on our costs of keeping you informed as water contact. Brodsky noted that the low as possible. athletes had no complaints about the river swim portion of the triathlon, which is combined with a run and a bicycle race. Then again, die-hard triathletes are used to swimming in places like the . District of Columbia Mayor Adrian Fenty, a seasoned triathlete, finished tenth in the elite male category, and spent almost a PAID half-hour in the water. U.S. Postage Rockville, MD Permit No. 800 Non-Profit Org.

Potomac Basin Printed on recycled paper with soy-based ink

Editors: Curtis M. Dalpra Jennifer D. Willoughby

Published six times a year by the Interstate Commission on the Potomac River Basin, 51 Monroe St., Suite PE-08, Rockville, MD 20850. (301) 984-1908. (ISSN 1072-8627) E-Mail: [email protected] Internet: http://www.potomacriver.org Joseph K. Hoffman, Executive Director This publication does not necessarily reflect official Commission policies. Funds for the Reporter are provided by the U.S. Environmental Protection Agency and the signatory bodies to ICPRB: District of Columbia, Maryland, Pennsylvania, Virginia, and West Virginia. Interstate Commission on the Potomac River Basin 51 Monroe St., Suite PE-08 Rockville, MD 20850 Address Service Requested September/October 2007

431112.pmd 8 10/29/2007, 1:59 PM