1. A. General.

   1. (1) Numerical toxic substance criteria for ambient surface waters are established to protect human health or aquatic life.

   2. (2) Four types of numerical toxic substance criteria shall be adopted. The purpose of these criteria is to protect:

      1. (a) Human health through ingestion of public water supplies;
      2. (b) The wholesomeness of fish for human consumption;
      3. (c) Fresh, estuarine, and salt water aquatic life from acute toxicity impacts; and
      4. (d) Fresh, estuarine, and salt water aquatic life from chronic toxicity impacts.

2. B. Fresh Water, Estuarine, and Salt Water Boundaries.

   1. (1) For any toxic substance for which no estuarine criteria appear in Regulation .03-2G, Table 1, the salt water criteria apply in estuarine waters.

   2. (2) Fresh water and estuarine or salt water boundaries begin at specific points for the purpose of applying the numerical toxic substance criteria for aquatic life protection. These points are:

      1. (a) The stream segment and all tributaries which confluence with the stream segment upstream from the boundaries specified in §B(3) of this regulation are assumed to be fresh water.
      2. (b) Except for Sub-Basin 02-13-01—Coastal Area, the stream segment and all tributaries which confluence with the stream segment downstream from the boundaries specified in §B(3) of this regulation are assumed to be estuarine water.
      3. (c) In Sub-Basin 02-13-01—Coastal Area, the stream segment and all tributaries which confluence with the stream segment downstream from the boundaries specified in §B(3) of this regulation are assumed to be salt water.

      4. (d) Tributary headwaters. Since the headwaters of some tributaries to stream segments designated as estuarine or salt water may be fresh, the Department may:

         1. (i) Require the discharger to provide site specific salinity measurements or accept site specific salinity measurements provided voluntarily by the applicant; and
         2. (ii) Review the information provided in §B(2)(d)(i) of this regulation, and determine that the area is more appropriately designated as fresh water.

   3. (3) For the purpose of applying numerical toxic substance criteria, the following are designated as the boundaries between fresh waters and estuarine or salt waters:

      1. (a) Lower Susquehanna River Area (Sub-Basin 02-12-02)—All waters are fresh waters.

      2. (b) Coastal Area (Sub-Basin 02-13-01) boundaries are:

         1. (i) Bishopville Prong—State boat ramp at Daye Road;
         2. (ii) Birch Branch—Route 113;
         3. (iii) Middle Branch—Route 113;
         4. (iv) Church Branch—Route 113;
         5. (v) Turville Creek—Route 589;
         6. (vi) Ayer Creek—Route 376;
         7. (vii) Newport Creek—Hayes Landing Road; and
         8. (viii) Poplartown Creek—Beaverdam Creek Road.

      3. (c) Pocomoke River Area (Sub-Basin 02-13-02) boundaries are:

         1. (i) Pocomoke River—A line connecting the mouth of Bullbegger Creek and the east entrance of Fair Hill Channel; and
         2. (ii) Manokin River—Sharps Point.

      4. (d) Nanticoke River Area (Sub-Basin 02-13-03) boundaries are:

         1. (i) Nanticoke River—A line connecting Newfoundland Point and Hat Crown Point (includes Marshyhope Creek);
         2. (ii) Wicomico River—A line connecting Pine Beach and Holland Point;
         3. (iii) Blackwater River—Mouth at Snake Island; and
         4. (iv) Transquaking River—Mouth at Fishing Bay.
      5. (e) Choptank River Area (Sub-Basin 02-13-04) boundary is a line connecting Bow Knee Point and Wrights Wharf.

      6. (f) Chester River Area (Sub-Basin 02-13-05) boundaries are:

         1. (i) Chester River—A line connecting Piney Grove and Primrose Point;
         2. (ii) Grays Inn Creek—A line crossing the creek at Cherry Tree Point;
         3. (iii) Herringtown Creek—All waters are fresh;
         4. (iv) West Fork Langford Creek—A line crossing creek at Fox Point;
         5. (v) East Fork Langford Creek—A line connecting Piney Point and Longmarsh Point;
         6. (vi) Philip Creek—All waters are fresh;
         7. (vii) Reed Creek—Tilghmans Neck Road;
         8. (viii) Corsica Creek—A line crossing the creek at Jacobs Nose;
         9. (ix) Emory Creek—All waters are estuarine water; and
         10. (x) All tributaries to the Chester River upstream from Deep Point.
      7. (g) Elk River Area (Sub-Basin 02-13-06)—All waters are fresh water.
      8. (h) Bush River Area (Sub-Basin 02-13-07)—All waters are fresh water.
      9. (i) Gunpowder River Area (Sub-Basin 02-13-08)—All waters are fresh water.

      10. (j) Patapsco River Area (Sub-Basin 02-13-09) boundaries are:

          1. (i) Patapsco River—A line connecting Lazaretto Point and the southern terminus of the Baltimore Harbor Tunnel; and
          2. (ii) Back River—a line connecting Rocky Point and Cuckhold Point.

      11. (k) West Chesapeake Bay Area (Sub-Basin 02-13-09) boundaries are:

          1. (i) Severn River—Bridge on State Highway 3;
          2. (ii) All tributaries to the Severn River upstream from MD Route 648;
          3. (iii) Magothy River—A line connecting Henderson Point and Pea Patch Point;
          4. (iv) All tributaries to the Magothy River are fresh water; and
          5. (v) South River—A line drawn due north from Beards Point.
      12. (l) Patuxent River Area (Sub-Basin 02-13-11) boundary is a line connecting Chalk Point and God's Grace Point.

      13. (m) Lower Potomac River Area (Sub-Basin 02-14-01) boundaries are:

          1. (i) Potomac River—A line connecting Upper Cedar Point and Chotank Creek; and
          2. (ii) All Maryland tributaries of the Potomac River upstream from St. Catherine Island are fresh water.
      14. (n) Washington Metropolitan Area (Sub-Basin 02-14-02)—All waters are fresh water.
      15. (o) Middle Potomac River Area (Sub-Basin 02-14-03)—All waters are fresh water.
      16. (p) Upper Potomac River Area (Sub-Basin 02-14-05)—All waters are fresh water.
      17. (q) North Branch Potomac River Area (Sub-Basin 02-14-10)—All waters are fresh water.
      18. (r) Youghiogheny River Area (Sub-Basin 05-02-02)—All waters are fresh water.
      19. (s) Conewago Creek Area (Sub-Basin 02-05-03)—All waters are fresh water.
      20. (t) Chesapeake Bay Proper (Sub-Basin 02-13-99) boundary is a line connecting Booby Point (39.284206 north latitude, -76.381400 west longitude) with Handy's Point (39.291944 north latitude, -76.181388 west longitude).

Authority: Environment Article, §§9-303.1, 9-313 — 9-316, 9-319, 9-320 — 9-325, 9-327, and 9-328, Annotated Code of Maryland

Effective date: September 1, 1974 (1:1 Md. R. 33)

COMAR 10.50.01.02, .04, and .03 recodified to COMAR 26.08.02.01, .03, and.04, respectively

Stream Segment Classification Tables codified as Regulation .02

Regulation .01 amended effective April 21, 1978 (5:8 Md. R. 593); July 11, 1980 (7:14 Md. R. 1348); December 3, 1984 (11:24 Md. R. 2070)

Regulation .01D amended effective May 24, 1982 (9:10 Md. R. 1022)

Regulation .01I amended effective June 6, 1983 (10:11 Md. R. 976); December 19, 1983 (10:25 Md. R. 2269)

Regulation .03 amended effective August 3, 1981 (8:15 Md. R. 1308)

Regulation .03A and D amended effective December 19, 1983 (10:25 Md. R. 2269)

Regulation .04B—E amended effective July 28, 1978 (5:15 Md. R. 1187)

Regulation .04 repealed effective July 11, 1980 (7:14 Md. R. 1348)

Regulation .04 adopted effective November 18, 1985 (12:23 Md. R. 2220)

Chapter revised effective June 27, 1988 (15:13 Md. R. 1556)

Regulation .02B amended effective May 1, 1989 (16:8 Md. R. 911); October 30, 1989 (16:21 Md. R. 2263)

Regulation .05A amended effective May 1, 1989 (16:8 Md. R. 911)

Regulation .07A amended effective May 1, 1989 (16:8 Md. R. 911)

Regulation .07G amended effective October 30, 1989 (16:21 Md. R. 2263)

Regulation .08A amended effective May 1, 1989 (16:8 Md. R. 911)

Regulation .08O amended effective October 30, 1989 (16:21 Md. R. 2263)

Regulation .08Q amended effective May 1, 1989 (16:8 Md. R. 911)

Regulation .09D amended effective October 30, 1989 (16:21 Md. R. 2263)

Regulation .10E amended effective February 19, 1990 (17:3 Md. R. 303)

Regulation .11B amended effective February 19, 1990 (17:3 Md. R. 303)

Regulation .12 adopted effective February 19, 1990 (17:3 Md. R. 303)

Regulation .13 adopted effective February 19, 1990 (17:3 Md. R. 303)

Chapter revised effective April 16, 1990 (17:7 Md. R. 854)

Regulation .01B amended effective April 26, 2001 (28:2 Md. R. 101); April 28, 2014 (41:8 Md. R. 474)

Regulation .02A amended effective April 26, 2001 (28:2 Md. R. 101)

Regulation .02B amended effective August 29, 2005 (32:17 Md. R. 1440); April 19, 2010 (37:8 Md. R. 619); April 28, 2014 (41:8 Md. R. 474)

Regulation .02-1 adopted effective August 29, 2005 (32:17 Md. R. 1440)

Regulation .02-1A amended effective April 28, 2014 (41:8 Md. R. 474)

Regulation .02-1F, G amended effective October 31, 2022 (49:22 Md. R. 980)

Regulation .03A amended effective January 2, 1995 (21:26 Md. R. 2195)

Regulation .03B amended effective June 7, 1993 (20:11 Md. R. 917); July 5, 2004 (31:13 Md. R. 995)

Regulation .03-1B amended effective April 9, 2018 (45:7 Md. R. 347)

Regulation .03-2 amended effective January 7, 1991 (17:26 Md. R. 2978); June 7, 1993 (20:11 Md. R. 917); March 25, 1996 (23:6 Md. R. 477); April 26, 2001 (28:2 Md. R. 101); April 19, 2010 (37:8 Md. R. 619)

Regulation .03-2C amended effective July 5, 2004 (31:13 Md. R. 995)

Regulation .03-2D, F amended effective February 5, 2024 (51:2 Md. R. 77)

Regulation .03-2G amended effective July 19, 2004 (31:14 Md. R. 1080); November 29, 2010 (37:24 Md. R. 1660); April 28, 2014 (41:8 Md. R. 474); October 31, 2022 (49:22 Md. R. 980); February 5, 2024 (51:2 Md. R. 77)

Regulation .03-2H, I amended effective April 28, 2014 (41:8 Md. R. 474); October 31, 2022 (49:22 Md. R. 980)

Regulation .03-2I amended effective February 5, 2024 (51:2 Md. R. 77)

Regulation .03-3 amended effective July 5, 2004 (31:13 Md. R. 995); August 29, 2005 (32:17 Md. R. 1440); April 28, 2014 (41:8 Md. R. 474)

Regulation .03-3A amended effective April 9, 2018 (45:7 Md. R. 347)

Regulation .03-3C amended effective April 19, 2010 (37:8 Md. R. 619); November 29, 2010 (37:24 Md. R. 1660); April 2, 2012 (39:6 Md. R. 410); October 31, 2022 (49:22 Md. R. 980)

Regulation .03-3E amended effective October 28, 1991 (18:21 Md. R. 2311)

Regulation .03-3H adopted effective April 19, 2010 (37:8 Md. R. 619)

Regulation .03-4 adopted effective July 19, 2004 (31:14 Md. R. 1081)

Regulation .04 amended effective April 26, 2001 (28:2 Md. R. 101); October 31, 2022 (49:22 Md. R. 980)

Regulation .04A amended effective April 28, 2014 (41:8 Md. R. 474)

Regulation .04C amended effective January 7, 1991 (17:26 Md. R. 2978)

Regulation .04-1 repealed and new Regulation .04-1 adopted effective October 31, 2022 (49:22 Md. R. 980)

Regulation .04-1 adopted effective February 5, 2001 (28:2 Md. R. 104)

Regulation .04-1 recodified to be Regulation .04-2 and new Regulation .04-1 adopted effective July 19, 2004 (31:14 Md. R. 1081)

Regulation .04-1D amended effective November 29, 2010 (37:24 Md. R. 1660)

Regulation .04-1O amended effective November 29, 2010 (37:24 Md. R. 1660); April 28, 2014 (41:8 Md. R. 474); April 9, 2018 (45:7 Md. R. 347)

Regulation .04-2 repealed and new Regulation .04-2 adopted effective October 31, 2022 (49:22 Md. R. 980)

Regulation .04-3 adopted effective October 31, 2022 (49:22 Md. R. 980)

Regulation .05 amended effective June 7, 1993 (20:11 Md. R. 917)

Regulation .05A amended effective July 5, 2004 (31:13 Md. R. 995)

Regulation .05B recodified to Regulation .05-1 effective June 7, 1993 (20:11 Md. R. 917)

Regulation .05D amended effective January 17, 1994 (21:1 Md. R. 34)

Regulation .05-1 amended effective November 29, 2010 (37:24 Md. R. 1660)

Regulation .07 amended effective August 29, 2005 (32:17 Md. R. 1441)

Regulation .07E amended effective April 28, 2014 (41:8 Md. R. 474)

Regulation .07E repealed effective October 31, 2022 (49:22 Md. R. 980)

Regulation .07F, G repealed effective April 28, 2014 (41:8 Md. R. 474)

Regulation .08 repealed and new Regulation .08 adopted effective August 29, 2005 (32:17 Md. R. 1442)

Regulation .08 amended effective April 19, 2010 (37:8 Md. R. 619); April 28, 2014 (41:8 Md. R. 474); April 9, 2018 (45:7 Md. R. 347); October 31, 2022 (49:22 Md. R. 980)

Regulation .08H and J amended effective April 13, 1992 (19:7 Md. R. 747)

Regulation .08J amended effective January 17, 1994 (21:1 Md. R. 34); October 24, 1994 (21:21 Md. R. 1815); May 22, 1995 (22:10 Md. R. 708); July 5, 2004 (31:13 Md. R. 995)

Regulation .08L amended effective November 29, 2010 (37:24 Md. R. 1660)

Regulation .08N amended effective October 28, 1991 (18:21 Md. R. 2311); January 17, 1994 (21:1 Md. R. 34); October 24, 1994 (21:21 Md. R. 1815)

Regulation .08O amended effective January 17, 1994 (21:1 Md. R. 34); May 22, 1995 (22:10 Md. R. 708)

Regulation .08Q amended effective January 17, 1994 (21:1 Md. R. 34); May 22, 1995 (22:10 Md. R. 708)

Regulation .09A amended effective October 20, 1997 (24:21 Md. R. 1453); December 22, 2014 (41:25 Md. R. 1486)

Regulation .09D amended effective January 19, 2004 (31:1 Md. R. 32); May 3, 2010 (37:9 Md. R. 673)

Regulation .10B amended effective February 5, 2001 (28:2 Md. R. 104)

Regulation .11B amended effective April 28, 2014 (41:8 Md. R. 474)