Ala. Admin. Code r. 335-7-15-.12 - Delineation Of Watersheds

Watersheds for all surface water intakes shall be delineated using the Hydrologic Unit Code (HUC), or other approved methods. Delineated watersheds shall extend upstream and laterally from intakes to the watershed topographic boundary, the next upstream dam (where applicable), and to the adjacent state boundary. Watersheds shall be depicted on US Geological Survey (USGS) topographic maps using a suitable scale between 1:100,000 and 1:24,000. Map overlays and the Geographical Information System (GIS), or other approved methods, may be used to depict various types of information such as large land areas, for the watershed and the Source Water Protection Area (SWPA). Maps of watershed delineations must show the location of intakes and known and potential contaminant sources, using the Global Positioning System (GPS) coordinates. The SWPA is the area designated for close scrutiny by the contaminant source inventory and protection, and shall be shown on the watershed map, or overlay, in accordance with the following:

(a) For river runs, creeks, and streams: The SWPA area shall extend from 1/4 mile downstream of an intake (where practicable) to:

1. Fifteen (15) miles upstream of the intake,

2. One-quarter mile below the next upstream intake,

3. The next upstream dam, or

4. The state boundary.

5. The SWPA shall extend laterally from the intake for a minimum distance of 500 feet beyond the edge of the body of water at summer pool elevation serving the intake. Special conditions, such as an area of known potential or suspected contaminant sources, may require the width of the SWPA to exceed 500 feet. Significant tributaries (tributaries draining an area of known, potential, or suspected contaminants) entering the SWPA shall be included as a part of the SWPA for a minimum of one mile upstream of the tributary and laterally to each side of the tributary for a minimum of 500 feet.

(b) For lakes and reservoirs with water surface areas exceeding 1000 acres the SWPA shall extend from 1/4 mile downstream of the intake (where practicable) to:

1. Five (5) miles upstream of the intake in all directions of potential flow toward the intake,

2. A minimum of 500 feet inland for land falling within the above five mile distance of potential flow towards the intake.

3. A minimum of one mile upstream and a minimum of 500 feet to each side of significant tributaries falling within the above five mile distance of flow towards the intake.

(c) For lakes and reservoirs with water surface areas equal to or less than 1000 acres the SWPA shall extend from 1/4 mile downstream of the intake (where practicable) to:

1. A minimum of 500 feet inland for the entire body of water or waters;

2. A minimum of one mile upstream and a minimum of 500 feet to each side of significant tributaries to the body of water.

Author: Edgar K. Hughes

Notes

Ala. Admin. Code r. 335-7-15-.12

New Rule: Filed November 7, 2005; effective December 12, 2005.

Statutory Authority: Code of Ala. 1975, §§ 22-23-33, 22-23-49, 22-22A-5, 22-22A-6.