Volume 12 / Issue 4 estuary news Summer 2002 Newsletter of the Delaware Estuary Program The Delaware Estuary and the Chesapeake Bay: Physical Differences that create Ecological Challenges By Jonathan H. Sharp, University of Delaware College of Marine Studies Almost 25 years ago, when I began a major research project completely than the Chesapeake. If you compute the total volume on the Delaware Estuary, there was a news note in the profes- of water held by the basin and the composite discharge of the sional journal Science that referred to the Delaware Bay as the rivers into the basin, the Delaware has a “flushing time” of Chesapeake’s “dirty little sister.” In the 1980’s, an editorial in about 100 days contrasted to that of the Chesapeake, which is the Delaware State News offered a more descriptive contrast 350 days. Perhaps more critical is the fact that the Chesapeake, between the two bodies of water: with its deep central portion and shal- “The Chesapeake is a sailboat gliding low narrow opening at the mouth, across sun-speckled water at sunset. stratifies in the summer while the The Delaware is a tanker lightering Delaware does not. This means that its dark oily cargo into a bleak barge the subsurface waters of the in dark gray water.” I am sure that Chesapeake Bay (deeper than about most readers of Estuary News can 15 feet) become isolated from the appreciate the inaccuracies of these surface and stagnant in the summer. somewhat derogatory comparisons. These bottom waters, receiving fallout Editorial comments aside, there are from the surface algal production, suf- differences between these two vitally fer from severe oxygen depletion important bodies of water. These dif- (hypoxia) to no oxygen at all (anoxia). ferences define how the Delaware Because the Delaware Bay waters Estuary is viewed by the public and are well mixed in the summer and how state and federal agencies manage flush rapidly, there are no problems these natural resources. with subsurface hypoxia and anoxia. This represents a very important differ- The Delaware and Chesapeake Bays ence between these two water bodies. have similar geological origins. The uplift of the Appalachian Mountains, In the past 50 years, in many estuaries completed about 70 million years and coastal waters across the United ago, which separated the Piedmont States and the rest of the developed highlands from the lower coastal world, there is good evidence that plain, created a fall line near Trenton loadings and concentrations of nitrogen that defines the head of the tides of and phosphorus plant nutrients have the Delaware Estuary; the Chesapeake fall line on the increased greatly. Increased levels of nutrients tend to increase Susquehanna River is of similar origin. Drainage of the the production of algae in these water bodies, especially of the Piedmont gave rise to the Delaware River channel carving microscopic phytoplankton. In the Chesapeake Bay, there is through the coastal plain on its transit to the Atlantic Ocean. concern that this has contributed to hypoxia and anoxia. The The current configuration of the estuaries occurred with the Delaware Estuary, with its different physical characteristics, retreat of the last glaciation about 11,000 years ago. Thus the does not have the same problem. To attack the problem in the Chesapeake and Delaware, carved by glaciation, have similar Chesapeake Bay, extensive reduction in nutrient inputs are origins but very different physical characteristics. mandated. No such need exists in the Delaware Estuary. The nutrient-associated oxygen depletion problem in the Chesapeake The Chesapeake Bay is five times larger than the Delaware; is viewed as a relatively new problem of the past few decades. it has a comparatively narrow, deep center with a shallow sill Today, there is considerable concern about the deterioration of near its mouth. The Delaware Bay, in contrast, is broad and environmental conditions of the Chesapeake Bay. shallow. In addition, the Delaware flushes more quickly and (continued on page 2) For more than a century, the Delaware Estuary, especially the We certainly should not conclude that the Delaware Estuary is urban river region near Philadelphia, had serious environmen- a “clean little sister” of the Chesapeake, but one of the most tal problems with respect to oxygen depletion. Owing to dis- pressing problems for the neighboring Chesapeake Bay is not charge of poorly treated sewage effluents, there was severe a similar problem for the Delaware and remedial action being oxygen depletion in surface waters called a primary biological implemented for the Chesapeake is not necessarily the same oxygen demand (BOD). More thorough treatment of sewage for the Delaware. The Delaware Estuary Program (DELEP) brought about by upgrades in the major sewage treatment has recognized these differences, which have influenced the plants has greatly reduced BOD, and as a result the oxygen DELEP Management Plan guiding how we use this valuable level in the Delaware River has increased dramatically in the resource. last 25 years. This oxygen increase constitutes one of the most successful estuarine water quality improvements of any Basic ecological processes are similar in all estuaries, but how estuary in the world. Thus, while the Chesapeake is suffering they are expressed varies with the physical features of the environmental deterioration from oxygen depletion, the estuary. It is important to recognize these differences when Delaware is showing an improvement. developing long-range plans that are appropriate for the spe- cific environment. This is exactly what we are trying to do for the Delaware Estuary. Updates from DELEP Information Management Toxics Advisory Advisory Committee (IMAC) Committee (TAC) The IMAC has received approval and funding for the “i-Map” The following Toxics Advisory Committee resolutions were pre- project. This project will use Internet mapping software to sented to the Commissioners at the May 31, 2002 Delaware allow users to respond to a series of questions that result in a River Basin Commission (DRBC) meeting: specific theme within the Delaware River Basin. For example, a person interested in kayaking the Delaware River would be • It was recommended that DRBC proceed with the devel- able to access flow information, as well as to identify portages opment and adoption of aquatic life and human health cri- and launch areas. Each theme will be displayed in the form of teria for toxic pollutants in Zone 1 of the Delaware River. an interactive map that the user can zoom, click on to get more detailed information, or print. The project is expected to be • It was recommended that a fish consumption rate of 17.5 completed this fall. Keep your eye out on the Delaware grams/day be used in Zones 1 - 6 for purposes of deriving Estuary Program’s web site at www.delep.org for its debut. human health water quality criteria. The TAC further rec- ommended that DRBC collect site-specific fish consump- tion data to serve as the basis for future revision of the human health water quality criteria in Zones 1 through 4. (The ‘fish consumption rate’ is a statistically derived value for the amount of fish consumed per person per day. The meetings of the DELEP Implementation Teams occur on a regular basis and are open to the public. For meeting dates and times, please call the individuals listed below: Public Participation Habitat and Living Resources Fish Consumption Implementation Team Implementation Team Advisory Team Kathy Klein Martha Maxwell-Doyle Tom Fikslin, DRBC (800) 445-4935 (609) 883-9500 ext. 215 (609) 883-9500 ext. 253 [email protected] [email protected] [email protected] The Delaware River Basin Commission also has three Advisory Committees that serve in the same capacity as the Implementation Teams: Monitoring Advisory Committee Information Management Toxics Advisory Committee Edward Santoro, Advisory Committee Tom Fikslin, DRBC Monitoring Coordinator Warren Huff, (609) 883-9500 ext. 237 (609) 883-9500 ext. 253 (609) 883-9500 ext. 268 [email protected] [email protected] [email protected] or Karl Heinicke, RIMS Coordinator (609) 883-9500 ext. 241 [email protected] Page 2 Volume 12 / Issue 4 Different populations and regions can have different fish are issued in the Delaware Estuary. Currently, the states of consumption rates. Fish consumption rates do not indi- Delaware, New Jersey, and Pennsylvania independently develop cate the amount of fish that is safe to eat, but rather are fish consumption advisories for the Estuary. In addition, no tools used in calculating necessary water quality targets coordinated program currently exists among the states for and estimating risks to public health.) informing the public of health risks for consuming contaminated fish. This results in incomplete and inconsistent advice to the The TAC is currently considering a two-day technical workshop public. that would present current studies such as atmospheric depo- The FCAT’s goal is to develop a methodology to be used by sition to members of the committee. the states to establish consistent and clearly understandable fish consumption advisories for the Estuary, which would include Fish Consumption establishing uniform collection and analysis procedures, com- Advisory Team (FCAT) patible risk assessment procedures, and risk communication strategies. A Fish Consumption Advisory Team has been established to address the consistency of fish consumption advisories that Tidings: News from Around the Region Cooper River Fishway Restoration Team Receives 2001 Alewife Coastal America Partnership (Alosa pseudoharengus) Award Blueback herring (Alosa aestivalis) By Catherine Libertz, Delaware Estuary Program Coordinator, U.S. Environmental Protection Agency Region III On May 13, 2002 a Coastal America Partnership Award was In anticipation of the fishways being installed, a streambank given to the participants of the Cooper River Fishway restoration project was completed under the leadership of the Restoration Team.