Where Land under Water Bodies and Waterways is composed of pervious material, such land represents a point of exchange between surface and ground water.
The physical nature of Land under Water Bodies and Waterways is highly variable, ranging from deep organic and fine sedimentary deposits to rocks and bedrock. The organic soils and sediments play an important role in the process of detaining and removing dissolved and particulate nutrients (such as nitrogen and phosphorous) from the surface water above. They also serve as traps for toxic substances (such as heavy metal compounds).
Land under Water Bodies and Waterways, in conjunction with banks, serves to confine floodwater within a definite channel during the most frequent storms. Filling within this channel blocks flows which in turn causes backwater and overbank flooding during such storms. An alteration of Land under Water Bodies and Waterways that causes water to frequently spread out over a larger area at a lower depth increases the amount of property which is routinely flooded. Additionally, it results in an elevation of water temperature and a decrease in habitat in the main channel, both of which are detrimental to fisheries, particularly during periods of warm weather and low flows.
Land under rivers, streams and creeks that is composed of gravel allows the circulation of cold, well oxygenated water necessary for the survival of important game fish species such as brook trout (Salvelinus frontinalis), rainbow trout (Oncorhynchus mykiss), brown trout (Salmo trutto) and atlantic salmon (Salmon salar). River, stream and creek bottoms with a diverse structure composed of gravel, large and small boulders and rock outcrops provides escape cover and resting areas for the above mentioned game fish species (salmonids). Such bottom type also provides areas for the production of aquatic insects essential to fisheries.
Land under ponds and lakes is vital to a large assortment of warm water fish during spawning periods. Species such as large mouth bass (Micropterus salmoides), smallmouth bass (Micropterus dolomieui), blue gills (Lepomis macrochirus), pumpkinseeds (Lepomis gibbosus), black crappie (Pomoxis nigromaculatus) and rock bass (Ambloplites rupestris) build nests on the lake and bottom substrates within which they shed fertilize their eggs.
The plant community composition and structure, hydrologic regime, topography, soil composition and water quality of land under water bodies and waterways provide important food, shelter, migratory and overwintering areas, and breeding areas for wildlife. Certain submerged, rooted vegetation is eaten by water fowl and some mammals. Some amphibians (as well as some invertebrate species eaten by vertebrate wildlife) attach their eggs to such vegetation. Some aquatic vegetation protruding out of the water is also used for nesting, and many species use dead vegetation resting on land under water but protruding above the surface for feeding and basking Soil composition is also important for hibernation and for animals which begin to burrow their tunnels under water. Hydrologic regime, topography, and water quality not only affect vegetation, but also determine which species feed in an area.
310 CMR, § 10.56