Unless clearly indicated by context, the following words and terms, when used in this part, shall have meanings as defined below:

1. (1) “Billing volume” means normal storage designed to contain sediment accumulation over the life of the dam;
2. (2) “Chief engineer” means the Deputy Director/Chief Engineer of the Arkansas Natural Resources Commission;
3. (3) “Commission” means the Arkansas Natural Resources Commission;

4. (4)

   1. (A) “Construction costs” means estimated or actual material and labor costs, including:

      1. (i) Excavation;
      2. (ii) Embankment placement;
      3. (iii) Spillways;
      4. (iv) Gates;
      5. (v) Valves; and
      6. (vi) Conduits.

   2. (B) Shall not include costs of:

      1. (i) Land;
      2. (ii) Reservoir clearing;
      3. (iii) Engineering;
      4. (iv) Water treatment facilities; or
      5. (v) Other costs not directly related to construction of the dam;

5. (5)

   1. (A) “Dam” means any barrier, including one for flood detention, designed to impound liquid volumes.
   2. (B) This shall not include highway, railroad, or other roadway embankments, including low water crossings that may temporarily detain floodwater, levees designed to prevent inundation by floodwater, or closed dikes to temporarily impound liquids in the event of emergencies, and those barriers not exempt by 15 CAR § 23-103 or § 23-104;
6. (6) “Director” means the Director of the Arkansas Natural Resources Commission;
7. (7) “Effective crest of the dam” means the elevation of the lowest point on the crest of the dam excluding spillways;
8. (8) “Height of dam” means the vertical distance from the effective crest of the dam to the lowest elevation on the downstream toe of the dam;
9. (9) “Maximum storage” means the volume of the impoundment created by the dam at the effective crest of the dam;

10. (10) “Minimum release” means the daily quantity of water that must be released to:

    1. (A) Preserve downstream riparian rights or permitted nonriparian rights; or
    2. (B) Meet instream water needs including, but not limited to, those of fish and wildlife;
11. (11) “Normal storage” means the volume of the impoundment created by the dam at the lowest uncontrolled spillway crest;

12. (12)

    1. (A) “PMF” (probable maximum flood) means the maximum runoff condition resulting from the most severe combination of hydrologic and meteorologic conditions that are reasonably possible for a given watershed.
    2. (B) The PMF is the maximum runoff computed from the spatial and temporal distribution of the PMP over the watershed;
13. (13) “PMP” (probable maximum precipitation) means the greatest theoretical depth of precipitation (rainfall equivalent) for a given duration that is physically possible over a given size storm area at a particular geographical location at a certain time of the year; and
14. (14) “Spillway design flood” (SDF) means the largest flood the spillway must pass without overtopping a dam.