PROBLEM: The tidal Anacostia River suffers from overall poor water quality due to a variety of factors that plague many urban rivers. Due to intense development, a high percentage of impervious surface and high stormwater runoff volumes, it receives large amounts of pollutants including sediment, excess nutrients, toxics and trash and debris. Additionally, with almost every significant rainfall event, it experiences combined sewer and stormwater overflows which discharge sewage and other pollutants directly into the river. Many of these factors contribute to both chronically low dissolved oxygen levels that frequently violate water quality standards and threaten aquatic life and high bacterial levels which make water contact activities (such as swimming and wading) unsafe.

Sediment

For well over 200 years, excessive erosion and subsequent sediment deposition have been a major Anacostia River problem. High sedimentation rates, associated with early tobacco growing in the 17th and 18th centuries, necessitated the first dredging of the Anacostia River in 1804. Continued high sediment deposition in the tidal river ultimately led, by 1830, to the demise and abandonment of Bladensburg as a major Atlantic seaport (Wright, 1977). Because the Anacostia River functions in many ways like a tidal lake, it is a very efficient sediment trap. It has been estimated that approximately 85 percent of the incoming sediment load remains trapped within the river (Scatena, 1986). This has necessitated frequent and costly sediment removal to maintain marina areas and navigation channels (Figure 6). In addition to adversely impacting navigation, reducing water clarity, degrading aquatic habitat and associated biota, sediment serves as a binding site for a broad range of urban pollutants and toxicants. These include: petroleum hydrocarbons, trace metals such as lead, mercury, cadmium, copper and zinc, PCBs, pesticides, herbicides, nutrients and bacteria.   Figure 6. M-NCPPC's Hydraulic Dredge (a.k.a Mud Cat) Used for Removing River Sediment Sediment-related stream quality degradation in the non-tidal portion of the Anacostia has been equally profound. Related impacts include: impairment of riffle and pool habitat through deposition of fine sediments such as sand, silt and clay; accelerated streambank and streambed erosion during stormflows; and high suspended solids loads which impair the biological community by obscuring the water for sight feeders and clogging or irritating exposed gills. Using general suspended sediment-watershed area curves (Schueler, 1987), COG staff estimated annual total suspended solids loads (TSS) generated in the Anacostia watershed. As seen in Figure 7, the two largest subwatersheds (Northwest and Northeast Branch) each contribute the largest total TSS loads. Not surprisingly, TSS loads are generally a function of drainage area and land use, with the largest subwatershed and/or most highly developed one contributing the largest load. TSS loads for the intensively developed Lower Beaverdam Creek subwatershed are the highest per unit area in the watershed. Annual TSS loadings in the Anacostia watershed are estimated to be 48,200 tons, for an average of 0.43 tons/acre/year (Warner et al., 1997).

Nutrients

In freshwater ecosystems, two nutrients, phosphorus and nitrogen, can significantly impact receiving waters. When present in sufficient concentrations they often trigger algal blooms, which eventually reduce the dissolved oxygen (DO) level of the water as decaying algal and other organic matter is broken down by microorganisms. Typical sources of phosphorus and nitrogen include fertilizers, animal wastes, automotive exhaust, organic material, soil, etc. Figure 7. Annual Total Suspended Solids (TSS), Total Phosphorus (TP) and Total Nitrogen (TN) Pollutant Load Estimates, 1990 (data from Warner et al., 1997) Using the Simple Method (Schueler, 1987), COG staff estimated total phosphorus (TP) and total nitrogen (TN) loads for the entire Anacostia watershed. As expected, the larger Northeast Branch portion of the watershed generates the largest TP and TN loads (50,000 and 340,000 lbs/year, respectively). However, when viewed on a pollutant load per acre basis, it is evident that the Lower Tributaries and Tidal Anacostia areas contribute disproportionately to the overall problem. Much of this is due to the high amount of impervious surface, low number of stormwater management controls, age of sanitary sewer lines, storm drainage and combined sewer systems present.

Combined Sewer Overflows-CSOs

Approximately 60 percent of the Anacostia watershed within the District of Columbia drains directly to the tidal Anacostia River via a combined sanitary and storm sewer system dating back as early as the late 1800s. There are 11 major combined sewer outfalls to the Anacostia River and all discharge in the vicinity of the East Capitol Street and South Capitol Street bridges. A CSO event occurs when rainfall exceeds the capacity of this combined system causing discharges of untreated sanitary waste and stormwater directly into the river. On average, overflows occur roughly 40 to 50 times a year, resulting in approximately 1.3 billion gallons of sanitary waste discharged to the tidal river. CSOs are the primary point source pollutants degrading the Anacostia River's water quality. However, only about six percent of the annual pollutant loads to the Anacostia River are from CSOs compared to about 94 percent from nonpoint sources (Warner et al., 1997). In recognition of the CSO problem, the District of Columbia initiated its CSO Abatement Program in the early 1980s (Nemura and Pontikakis-Coyne, 1991). Retrofitting of existing combined sewer systems, between 1988 to 1990, with inflatable dams and construction of an overflow treatment facility (a.k.a., swirl concentrator) have produced some improvement. However, it is estimated that well over $1 billion dollars may be required to correct the existing CSO problem.

Toxics

Toxics refer to a variety of contaminants including trace metals such as arsenic, mercury, copper, cadmium and lead; and organic compounds such as PAHs (polycyclic aromatic hydrocarbons), PCBs (polychlorinated biphenyls) and pesticides and herbicides (e.g., DDT, Chlordane and atrazine) which reach receiving waters from stormwater runoff, atmospheric deposition and industrial and municipal discharges.   Figure 9. Location and Relative Size of CSO Discharges to the Tidal Anacostia River (COG, 1998). These contaminants typically cling to particles suspended in water and settle to the bottom, whereupon, they can become ingested by bottom feeding organisms and potentially find their way up the food chain. As seen in Figure 9, the Anacostia River is one of three areas in the Chesapeake Bay recognized as posing a significant risk to aquatic life due to high levels of sediment contamination. It has been designated by the Chesapeake Bay Program as a "Region of Concern" and the District of Columbia Department of Consumer and Regulatory Affairs has developed an "Action Plan" to address the issue of toxics in the river (CBP, 1995).

Figure 10. Sediment Concentrations of Select Organic Compounds in the Anacostia River and Kingman Lake, 1991 (modified from Velinsky et al., 1992). Several studies of tidal river sediments have found PCBs, DDT, DDE, Chlordane, trace metals and PAHs at detectable levels at all tidal Anacostia River sampling stations with levels of PCBs and Chlordane exceeding suggested criteria throughout the tidal river. However, the source(s) of contaminants could not be definitively determined (LTI, 1990). A subsequent study of tidal river sediments conducted in 1991 found concentrations of trace metals, such as cadmium, mercury, lead and zinc in the vicinity of the Washington Navy Yard to be at levels several times those expected to occur naturally. In addition, the study also found sharp increases in two organic sediment contaminants, DDT and PCB, just downstream of the Navy Yard. Potential sources identified include: the Navy Yard (Figure 10), the Bureau of Engraving and Printing, the old Lionel freight yard and the U.S. Botanical Gardens. In contrast, concentrations of Chlordane were highest in and just downstream of Kingman Lake. Currently, a major initiative, led by the District of Columbia Department of Health, is underway to study both toxic loadings to the tidal river from the Northwest and Northeast Branches, as well as, the control of and management of contaminated river sediments. Because of elevated levels of PCBs and Chlordane found in fish tissue, the District of Columbia, in 1994, issued a fish consumption advisory recommending that no bottom dwelling fish (such as catfish, eel and carp) be consumed and no more than 0.5 pounds of gamefish (such as largemouth bass and sunfish) be consumed by an adult per week. This advisory remains in effect.

Organic Loadings

Stormwater runoff, combined sewer overflows, leaking sewer lines, as well as natural processes, all contribute significant amounts of organic matter to the Anacostia River. Organic matter, which refers to anything derived from living organisms, must then be broken down or decomposed by microorganisms within the river. Depending on the timing and size of the load, the decomposition of this material can require a substantial amount of oxygen. One measure of the amount of oxygen required to decompose organic matter (principally organic carbon) over a fixed amount of time (typically 5 days) is termed the five-day biochemical oxygen demand (BOD5). While BOD5 does not account for the total oxygen demand to a water body, it does provide a good representation. When characterized as a pollutant load, BOD5 is expressed in terms of the total organic load to a receiving waterbody that is biologically oxidizable. Again, using the Simple Method (Schueler, 1987), COG staff estimated BOD5 pollutant loads for the entire Anacostia watershed. As seen in Figure 11, the Northwest and Northeast Branches (which together comprise approximately 74 percent of the total Anacostia watershed area) generate roughly 72 percent of the watershed's BOD5 loads. In general, BOD5 pollutant loads per subdrainage area increase with increasing subdrainage area size. The total BOD5 pollutant load for the entire watershed is an estimated 2,915,680 lbs/year. This level is approximately 5 to 6 times higher than under pre-European settlement conditions.   Figure 11. Annual Biochemical Oxygen Demand (BOD5) Pollutant Load Estimates, 1990 (data from Warner et al., 1997). High BOD5 loads, particularly during the warmer summer months, can reduce tidal river dissolved oxygen (DO) concentrations to levels that are lethal to fish and other aquatic organisms. Other factors that influence DO concentrations include river flow, water temperature, CSO events, algal blooms and sediment oxygen demand (SOD). SOD has been found to have a major negative influence on DO within the tidal Anacostia River, particularly in the vicinity of CSO outfalls (An, 1992). The District of Columbia has established a minimum DO concentration of 5.0 mg/L to support aquatic life. Unfortunately, chronically low DO levels below this threshold have been and continue to be a major problem along the tidal river (Figure 12). For a significant portion of the tidal river, from below Kenilworth Marsh downstream to approximately the South Capitol Street bridge, minimum summer DO levels were at or below 1.0 mg/L for the years 1987 to 1990 (Herson-Jones et al., 1994). While only two continuous DO monitoring stations have remained operational since 1990, data through 1996 show that very low summer DO levels are still a common occurrence.

Despite low DO levels, the number of fish kills reported in the tidal river over the past 10 years has generally been declining. The District of Columbia's Fisheries Management Branch which investigates reports of fish kills within the Anacostia River roughly defines a fish kill as the death of approximately 50 or more individuals within a spatially confined area (Tilak, 1997). From 1990 to 1996, the Fisheries Management Branch has observed two fish kills, one in June 1991 and the other in June 1992. Extremely low DO levels were believed responsible for the 1991 fish kill in which at least 10 fish species were identified. DO levels associated with the fish kill ranged from 0.4 to 1.8 mg/L(Tilak, 1997).   Figure 12. Summer Dissolved Oxygen Levels for the Tidal Anacostia River, 1987-1990 (Herson-Jones et al., 1994).

Trash and Debris

Figure 13. Anacostia River Bank North of New York Avenue Bridge (photo: DC WASA, 1993). It is estimated that over 20,000 tons of trash and debris enter the Anacostia River annually (PG DER, 1994). Without question, it remains one of the watershed's most highly visible and aesthetic problems (Figure 13). Trash and non-woody debris, which enter the watershed's tributaries and tidal river largely through urban storm drain systems, also have chemical and biological impacts on receiving waters including: interference with the establishment of aquatic plants, leaching of toxics from certain types of trash such as used oil filters and batteries, and floating trash hazards to wildlife through ingestion of or entanglement in floating debris (Herson-Jones et al., 1994). The types of trash and debris and the sources are many, making the management of this ubiquitous problem quite a formidable task (Figure 14). In 1992, the Floating Debris Removal Program for the Anacostia and Potomac Rivers was developed by the District of Columbia Department of Public Works as a pilot project to address debris control problems intrinsic to the tidal Anacostia River. These control problems include: relatively low flow rates and long turnover times of approximately 90 days in flushing out debris, many stormwater and CSO outfalls, and many mudflats and deltas exposed at low tides, all of which tend to retain debris (Durrum, no date). While the collection of trash and debris does not address nor begin to control the sources of the problem, it does provide a means for quantifying it.

The District of Columbia Water and Sewer Authority which currently runs the debris removal program collected approximately 960 tons of trash and debris in 1996. The significant increase collected in 1996 over the previous year was primarily due to several high runoff events (Figure 15). The increase in tonnage after 1993 was in part due to additional trash and debris collecting equipment (Donaldson, 1997).   Figure 14. District of Columbia Trash Skimmer Boat Removing Trash (photo: DC WASA, 1993).   Figure 15. Tons of Trash Removed Annually from the Tidal Anacostia River, 1993-1997 (DC WASA, 1998)

STRATEGY: Appreciably reduce and/or eliminate the impact from combined sewer/stormwater overflow events and stormwater pollutant loadings; effectively control stormwater loadings from new and existing development; remove trash and debris currently trapped in the tidal river as well as throughout the watershed; prevent future trash and debris deposition through community education and heighten public awareness; evaluate and address the problem of toxic sediments in the tidal river.

PROGRESS:

Reduced Fish Kills

As previously stated, there have been no reported fish kills in the tidal river since June 1992. Despite generally poor water quality conditions present, the tidal Anacostia continues to support a relatively stable and diverse population of gamefish (Figure 16). Also, while still well below historical levels, some 37 fish species called the tidal Anacostia River their home in 1996. Erosion and Sediment Control Since the mid-1980s, Montgomery and Prince George's counties and the District of Columbia have instituted stringent erosion and sediment and stormwater management controls for all new development. In the intervening years, hundreds of urban stormwater best management practices, such as wetlands, wet ponds, infiltration trenches, extended detention dry ponds, sand filters, etc., have been constructed. Figure 16. Representative Gamefish Distribution in the Tidal River, 1992-1996 (data from DC FMP, 1993-97).   Tidal River Sediment Transport Model As previously indicated, tidal Anacostia River sediments are highly impacted with organic and inorganic contaminants which have resulted in substantial biological impacts to benthos and fish. In 1997, the D.C. Department of Health-Environmental Health Administration worked closely with the Interstate Commission on the Potomac River Basin to develop a sediment transport model for determining deposition dynamics in the tidal Anacostia. Understanding the processes related to sediment transport will help answer questions on how sediment and related contaminants are deposited within the tidal Anacostia and into the Potomac River as well. The data will also help in developing remediation strategies for dealing with contaminated sediments in the Anacostia River.

Stormwater Retrofit

Figure 17. Hollywood Branch Peat Sand Filter, Montgomery County. Starting in 1989, the District of Columbia, Montgomery and Prince George's counties, the state of Maryland and later the U.S. Army Corps of Engineers undertook the installation of stormwater retrofit projects to include both new stormwater controls for previously uncontrolled development and the modification of existing stormwater controls to enhance their pollutant removal and stream channel protection performance. To date, approximately 200 stormwater retrofits have been proposed. Approximately 60 projects have either been constructed or are in a planning or design phase (Figures 17 and 18).

Figure 18. Kentlands No. 2 Wetland, Prince George's County. Under section 219 of the Water Resources Act, the U.S. Army Corps of Engineers (with sponsorship from Prince George's County) initiated a study of the impacts of stormwater discharges from Federal facilities in the Anacostia River watershed in Prince George's County. The two-year Federal Facilities Pollution Prevention Study, which was recently completed, identified potential stormwater retrofit projects at four Federal facility sites. In 1997, the Montgomery County Department of Environmental Protection completed a stormwater retrofit and stream restoration inventory for the environmentally sensitive Upper Paint Branch watershed. In addition to the 67 potential projects identified, the study included extensive stormflow modeling.

CSO Abatement
In 1989, the D.C. Department of Public Works and the U.S. Environmental Protection Agency installed an innovative swirl concentrator facility to reduce the combined sewer/stormwater overflow from the Northeast Boundary Interceptor which services the largest combined sewer system drainage area in the Anacostia at approximately 4,278 acres (Warner et al., 1997). Since becoming fully operational in 1990, it is estimated that the swirl concentrator has reduced both floatable material and total phosphorus discharges from this combined sewer system by approximately 25 to 30 percent. It also appears to have had a positive effect on DO levels in the river.

Storm Drain Monitoring
Since 1993, a total of 618 storm drain outfalls in the Prince George's County portion of the Anacostia have been screened by the County for possible illicit connections and pollution problems. Out of this total, 19 outfalls exhibited chemical pollution problems necessitating follow up enforcement actions.

Sanitary Sewer Line System Upgrade
The Washington Suburban Sanitary Commission, a regional water and sewer utility, has maintained an on-going rehabilitation and replacement program for aging sewer lines in the Anacostia's tributaries. The approximately $20 million dollar rehabilitation and replacement of aging trunk sewer lines in both Sligo Creek (Montgomery County) and Lower Beaverdam Creek (Prince George's County) was completed in 1997.

Toxic Sediments
In 1997, the D.C. Environmental Regulation Administration and the U.S. Environmental Protection Agency working with the Interstate Commission on the Potomac River Basin developed a remedial action plan for contaminated Anacostia River sediments.

Biennial Federal Workplan
In 1997, the U.S. Army Corps of Engineers completed its first Biennial Federal Workplan for the Anacostia River Watershed. The workplan includes an inventory of current, future and proposed projects and actions identified by Federal agencies that will contribute to the Anacostia restoration effort. The workplan also identifies gaps in Federal restoration efforts and provides recommendations on how to fill those gaps, including recommended activities on which Federal agencies should focus their efforts to achieve the ecosystem management approach for the watershed. The workplan also provides a detailed summary of current Anacostia restoration agreements and programs of Federal and local agencies.

Anacostia Federal Facilities Impact Assessment Study
Under this Congressionally mandated study, the U.S. Army Corps of Engineers with assistance from the Metropolitan Washington Council of Governments in 1997 identified over 50 stormwater retrofit, stream restoration, wetland creation, drainage remediation and riparian reforestation projects and management measures at 11 Anacostia Federal facility sites. The study is expected to be completed in early 1998.

Subwatershed Restoration Plans
The D.C. Environmental Regulation Administration and the U.S. Environmental Protection Agency, via the Hickey Run Comprehensive Pollution Abatement Program, contracted with the Metropolitan Washington Council of Governments to develop the first Subwatershed Action Plan (Shepp, 1991) for the Anacostia (completed in 1991) and to develop and apply a prototype petroleum hydrocarbon storm drain tracing system (also implemented in 1991) for Hickey Run (Shepp, 1993).

Floatable Trash Reduction
Beginning in 1992, the D.C. Department of Public Works (DC DPW), the Prince George's County Department of Environmental Resources, the Prince George's County Maryland-National Capital Park and Planning Commission (M-NCPPC) and the Interstate Commission on the Potomac River Basin (ICPRB) developed floating trash management initiatives for the river and its larger tributaries. In 1993, DC DPW began using a small fleet of skimmer boats to remove trash and debris from the river. M-NCPPC, with assistance from the ICPRB and local volunteers, operated intermittently between 1993 and 1995, a trash boom upstream of the Bladensburg Marina to test the trapping efficacy of this technique. Over eight tons of floating debris were removed during the six-month-long trial period.

Figure 19. Storm Drain Stenciling (photo: PG DER, 1996).

The District of Columbia and Montgomery and Prince George's counties supported citizen initiatives to include stream cleanups and "Don't Dump" storm drain inlet stenciling, which identifies a storm drain's connection to the Anacostia watershed (Figure 19).

In 1995, the AWRC established a Trash Workgroup which subsequently developed a report and recommendations on trash reduction in the Anacostia. As a result, the workgroup in coordination with the AWRC will continue to develop initiatives designed to address trash and debris issues throughout the watershed.

The AWRC's Anacostia Citizens Advisory Committee (AWCAC) planned and conducted the first annual watershed-wide Anacostia River Cleanup Day. The April 1997 event, which both raised public awareness of the trash problem in the watershed and increased stream stewardship, brought together 800 volunteers who collected nearly 30 tons of trash and debris. The event, which was sponsored by AWCAC, the Anacostia Watershed Society and Seafarer's Yacht Club had three staging points: Bladensburg Marina, Kenilworth Park and Anacostia Park. The U.S. Army Corps of Engineers provided two trash barges to help pick up the trash. Additional equipment and supplies - front end loaders, generators, trucks, vans, canoes and boats, radios, phones and trash containers - were provided by a number of District of Columbia agencies, the Maryland-National Capital Park and Planning Commission, the towns of Bladensburg and Cheverly, Prince George's County Department of Environmental Resources, Browning-Ferris Industries and Washington Gas.

Figure 20. Submerged Aquatic Vegetation in the Tidal River (data from VIMS, 1998).

Submerged Aquatic Vegetation
Submerged aquatic vegetation (SAV) helps to improve water quality by filtering contaminants, using nutrients for growth and releasing dissolved oxygen. SAV also provides important habitat for fish and food for waterfowl. Poor water clarity prevents SAV growth. Unfortunately, for most of this century, SAV has been absent from the Anacostia River. However, in recent years, the tidal Anacostia River has shown slight signs of improved clarity, particulary in the lower reaches which are more strongly influenced by clearer Potomac River water. As a result, SAV such as wild celery, coontail, hydrilla, water stargrass and milfoil have begun to slowly establish themselves in the Anacostia River downstream of the East Capitol Street bridge (Figure 20).