Tennessee Hydrologic Determination

Tennessee Hydrologic Determination (HDT) and Jurisdictional Determinations (JD) are conducted by our trained field staff and follow the Tennessee Department of Environment and Conservation Division of Water Pollution ControlGuidance For Making Hydrologic Determinations. This is required by law within the state of Tennessee under the following statute.

The following is taken from the TN statute:

Public Chapter No. 464 PUBLIC ACTS, 2009 1
Tennessee Code Annotated, Section 69-3-103, is amended by
adding the following language as new, appropriately designated subsections:
( ) “Wet weather conveyance” means, notwithstanding any other law or
rule to the contrary, man-made or natural watercourses, including natural
watercourses that have been modified by channelization:
(1) That flow only in direct response to precipitation runoff in their
immediate locality;
(2) Whose channels are at all times above the groundwater table;
(3) That are not suitable for drinking water supplies; and
(4) In which hydrological and biological analyses indicate that,
under normal weather conditions, due to naturally occurring ephemeral or
low flow there is not sufficient water to support fish, or multiple
populations of obligate lotic aquatic organisms whose life cycle includes
an aquatic phase of at least two months;

( ) “Obligate lotic aquatic organisms” means organisms that require
flowing water for all or almost all of the aquatic phase of their life cycles;

( ) “Stream” means a surface water that is not a wet weather conveyance;

( ) “Watercourse” means a man-made or natural hydrologic feature with a
defined linear channel which discretely conveys flowing water, as opposed to


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