composed primarily of fresh water estuarine coastal lower water column estuarine tidal riverine coastal lower water column A layer of fresh estuarine water which extends from an estuarine pycnocline or mid-depth to the estuarine bed and from the land-water interface to a fiat boundary where the estuary bed below the water column reaches a depth of 4 meters. https://cmecscatalog.org/cmecs/classification/unit/606.html This class aligns to the Coastal and Marine Ecological Classification Standard (CMECS). In ENVO, we may adapt the definition for consistency, but the semantics (meaning) of the term should be unaffected. Please consult the CMECS catalogue (https://cmecscatalog.org/) for authoritative and semantically unconstrained definitions. CMECS:606 "Mid-depth", present in many CMECS classes, is ambiguous and needs refinement. What causes this freshwater layer to be "tidal" is not clearly specified in the current CMECS definition. envoCmecs envoMarine