Delware River Basin Commission Lower Delaware National Wild and Scenic River Delaware River Basin (NPS) Delaware River Keeper
Science Online (use for: wetlands, lakes, tides, sandbar) Wetlands (EPA) Sandbars (Encyclopedia Britannica)
Science Online (plant reproduction) Plants Database (USDA)
Science Online (use for: ducks, great blue herons, fish species) Identifying Animal Footprints (Alderleaf)
Ticks (CDC) Poison Ivy (CDC) Sunburn (CDC)
Science Online (use for: pollution, water pollution, litter, food web) Pollution (Scorecard) Army Corps of Engineers "What is Dredging" (NOAA) Water Science School (USGS)