2.3: Riparian and Aquatic Ecosystems

Protect, conserve and restore healthy and biologically diverse riparian and aquatic ecosystems.

Other Information:

The health of plant and animal communities requires that flows in rivers and streams exhibit the natural range of variation in the flow regime, especially seasonally. Other physical and chemical parameters are also critical to the health of ecosystems. Understanding the range of needs for the diverse native aquatic and riparian populations within the Basin is a major challenge. Defining flow regime and water quality criteria to support healthy aquatic and riparian communities. Ecosystem needs for flow and water quality vary seasonally with the life cycles of aquatic and riparian species. Criteria are dependent on topography, elevation, and geology, and are specific to the assemblages of populations in a region, a watershed, or a stream’s reach. Additional investigation of the fresh water inflow requirements for estuarine ecosystems is needed. In the tidal portion of the Basin, present policy consists of meeting a flow target for the Delaware River at Trenton, New Jersey. The target is designed to maintain the 30 day average chloride concentration at or below 180 ppm at river mile 98 during repetition of drought-of-record conditions to protect industrial and potable supply needs. Currently a model is used to forecast salinity changes based on projected changes to the flow regime. The freshwater inflow needs of estuarine systems should be established and incorporated into flow scenario evaluations, and up-to-date information on climate change and sea level rise should be used when evaluating projected estuary conditions. Incorporating ecosystem requirements in water quality criteria and flow targets. The Basin states are using biological and physical criteria in addition to traditional chemical criteria for assessment and protection of aquatic life. There has been increased monitoring of biological assemblages, habitat conditions, stream morphology, and riparian conditions to determine overall ecological integrity of the Basin’s waters. Coordination and cooperation among agencies and nongovernmental organizations is necessary to effectively assess and manage the Delaware River and its tributary watersheds. This includes establishing minimum water quality and flow criteria to support consistent designated uses throughout the Basin. These criteria will not just be the minimum acceptable for the survival of adults, but adequate to support and protect all life stages and the reproduction of aquatic and riparian communities. Establishing a regional approach to sediment management. Sediment transport occurs when soils are eroded by moving water. Results of sediment transport can be beneficial or problematic. Floodwater deposition of rich alluvial soils can be a boon to agriculture, while sediment deposits in navigable waterways can block channels and create dangerous conditions for river traffic. Erosion of upland soils can result in the loss of tons of fertile topsoil into bays and oceans, increasing turbidity and smothering benthic habitat. Managing sediment requires paying attention to the “source” of eroded soils as well as the “sink” or place of deposition. Management of soil sources includes a variety of practices to keep soils from eroding (see discussions on stormwater management in “Key Result Area 3: Linking Land and Water Resource Management”). Management of soil “sinks” includes dredging unwanted sediment from ports and navigable channels, removing contaminated sediments from ecological systems and removing sediments to restore habitats. Managing sediments in a systems context has not been widely practiced, but regional sediment management is being increasingly recognized as a strategy for effective ecological and economic control of sediment as a valuable resource. A regional approach to sediment management uses sediment budgets, which include sediment sources and sinks and the identification of ongoing sediment management activities performed throughout the watershed. Sediment availability is linked with sediment needs within the system based on suitable quantity, quality, and timing. Through planning and coordination, such varied activities as navigable channel maintenance, habitat restoration, abandoned mine rehabilitation and beach nourishment projects can all be made more efficient and economical. Employing restoration techniques to improve impaired waters. Restoring hydrological and ecological function requires investments in research and agency support, but they can be successfully accomplished with major benefits to water resources and habitat. Environmental restoration is a relatively new field, and information needed to determine objectives and predict ecological response to restoration measures is sparse. Restoration of landscapes and waterways is presently as much an art as a science. Sharing information helps advance our understanding of restoration techniques. Protecting riparian and aquatic ecosystems. Commercially significant species thrive on a food base of non-game mammals, birds, fish, reptiles, amphibians, mussels, and invertebrates supported by the Delaware River and Bay. It is important to identify and protect the habitat and life stage requirements of key commercial, recreational, game, non-game, threatened, and endangered species so they survive and successfully reproduce throughout their natural ranges. Water flows and quality, the absence of non-native predators or competitors for habitat and food, and the abundance of food supply are all integral to the success of our native aquatic and riparian plants and animals. Limits on harvesting may be necessary to ensure a sufficient number of reproducing adults and the abundance of commercial species for future generations. Invasive species management. Identifying invaders, their means of distribution, and methods of controlling them offers a tremendous ecological and economic challenge. It also challenges the ability of our institutions to work cooperatively, since it requires supportive efforts among agencies, organizations and individuals in the fields of science and research, environmental protection, commerce, and transportation. • Competition from invasive species is second only to habitat loss in its impact on ecosystem integrity. This Key Result Area covers the importance of waterway corridors, both as the interface between the land and surface waters of the Basin, and for the numerous functions they provide to humans and aquatic communities. The quality and quantity of our water resources are affected by conditions and activities that may occur far from the actual water bodies. “Key Result Area 3: Linking Land and Water Resource Management,” looks at how the entire watershed, including its varied landscapes and land use activities, functions as a critical component of the hydrologic system, and how our management and decision-making structure can improve results for better water resource management.

Objective(s):

2.3.A: Conservation Plans

2.3.B: Fisheries Management

2.3.C: Wetlands

2.3.D: Riparian and Aquatic Habitat Protection

2.3.E: Invasive Species

2.3.F: Sediment Management

2.3.G: Fish Passage

2.3.H: Stream Channel Stabilization

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