Glossary D

Dam
A wall built across a stream or river to hold back water.

Dead drift
A drift that imitates the natural action of an insect by floating directly downstream with the current.

Declination
The difference in degrees between magnetic north (the direction the magnetic needle on a compass points) and true or geographic north (the direction maps are printed towards).

Dehydration
Excessive loss of water from the body. (more about dehydration)

Delta
A low, watery land formed at the mouth of a river. It is formed from the silt, sand and small rocks that flow downstream in the river and are deposited in the delta.

Desert
Dry, barren region usually sandy and without trees, little rainfall or practical use of land unless irrigated.

Divide
The highest ridge of land separating river basins.

Dorsal Fin
Dorsal meaning top. This is the large fin on top of the fish's back.

Downstream
The direction of a river's flow; toward the mouth of the river.

Draw
A usually dry creek bed or gulch that temporarily fills with water after a heavy rain, or seasonally.

Dressed fish
A fish which has been cleaned by removing the entrails. Dressed fish also may be filleted and/or have their head, gills and scales removed.

Duncan's loop
A monofilament knot used most often to tie a tippet to the eye of a hook. Also called a uni-knot.

Dune
A hill or a ridge made of sand. Dunes are shaped by the wind, and change all the time.