15a ncac 02b .0216       FRESH SURFACE WATER QUALITY STANDARDS FOR WS-IV WATERS

The following water quality standards apply to surface waters within water supply watersheds classified as WS-IV. Water quality standards applicable to Class C waters as described in Rule .0211 of this Section shall also apply to Class WS-IV waters.

(1)           The best usage of WS-IV waters shall be as follows:  a source of water supply for drinking, culinary, or food‑processing purposes for those users where a more protective WS‑I, WS‑II or WS‑III classification is not feasible and any other best usage specified for Class C waters;

(2)           The conditions related to the best usage shall be as follows:  waters of this class are protected as water supplies that are in moderately to highly developed watersheds or protected areas and meet average watershed development density levels as specified in Sub-Items (3)(b)(i)(A), (3)(b)(i)(B), (3)(b)(ii)(A) and (3)(b)(ii)(B) of this Rule; discharges that qualify for a General Permit pursuant to 15A NCAC 02H .0127, trout farm discharges, recycle (closed loop) systems that only discharge in response to 10‑year storm events, other stormwater discharges, and domestic wastewater discharges shall be allowed in the protected and critical areas; treated industrial wastewater discharges shall be allowed in the protected and critical areas; however, new industrial wastewater discharges in the critical area shall be required to meet the provisions of 15A NCAC 02B .0224(1)(b)(iv), (v) and (vii), and 15A NCAC 02B .0203; new industrial connections and expansions to existing municipal discharges with a pretreatment program pursuant to 15A NCAC 02H .0904 shall be allowed; the waters, following treatment required by the Division, shall meet the Maximum Contaminant Level concentrations considered safe for drinking, culinary, or food‑processing purposes that are specified in the national drinking water regulations and in the North Carolina Rules Governing Public Water Supplies, 15A NCAC 18C .1500.  Sources of water pollution that preclude any of these uses on either a short‑term or long‑term basis shall be considered to be violating a water quality standard.  The Class WS-II or WS-III classifications may be used to protect portions of Class WS-IV water supplies.  For reclassifications of these portions of WS-IV water supplies occurring after the July 1, 1992 statewide reclassification, the more protective classification requested by local governments shall be considered by the Commission when all local governments having jurisdiction in the affected area(s) have adopted a resolution and the appropriate ordinances to protect the watershed or the Commission acts to protect a watershed when one or more local governments has failed to adopt necessary protection measures;

(3)           Quality standards applicable to Class WS-IV Waters shall be as follows:

(a)           Sewage, industrial wastes, non‑process industrial wastes, or other wastes:  none shall be allowed except for those specified in Item (2) of this Rule and Rule .0104 of this Subchapter and none shall be allowed that have an adverse effect on human health or that are not treated to the satisfaction of the Commission and in accordance with the requirements of the Division.  Any dischargers or industrial users subject to pretreatment standards may be required by the Commission to disclose all chemical constituents present or potentially present in their wastes and chemicals that could be spilled or be present in runoff from their facility which may have an adverse impact on downstream water supplies.  These facilities may be required to have spill and treatment failure control plans as well as perform special monitoring for toxic substances;

(b)           Nonpoint Source and Stormwater Pollution:  none shall be allowed that would adversely impact the waters for use as water supply or any other designated use.

(i)            Nonpoint Source and Stormwater Pollution Control Criteria For Entire Watershed or Protected Area:

(A)          Low Density Option: development activities that require a Sedimentation/Erosion Control Plan in accordance with 15A NCAC 04 established by the North Carolina Sedimentation Control Commission or approved local government programs as delegated by the Sedimentation Control Commission shall be limited to no more than either: two dwelling units of single family detached development per acre (or 20,000 square foot lot excluding roadway right-of-way),or 24 percent built-upon on area for all other residential and non-residential development; or three dwelling units per acre,  or 36 percent built-upon area for projects without curb and gutter street systems in the protected area outside of the critical area; stormwater runoff from the development shall be transported by vegetated conveyances to the maximum extent practicable;

(B)          High Density Option: if new development activities that require a Sedimenta­tion/Erosion Control Plan exceed the low density requirements of Sub-Item (3)(b)(i)(A) of this Rule, then development shall control the runoff from the first inch of rainfall; new residential and non-residential development shall not exceed 70 percent built‑upon area;

(C)          Land within the critical and protected area shall be deemed compliant with the density requirements if the following condition is met: the density of all existing development at the time of reclassification does not exceed the density requirement when densities are averaged throughout the entire area;

(D)          Cluster development shall be allowed on a project‑by‑project basis as follows:

(I)            overall density of the project meets associated density or stormwater control requirements of this Rule;

(II)          buffers meet the minimum statewide water supply watershed protection requirements;

(III)        built‑upon areas shall be designed and located to minimize stormwater runoff impact to the receiving waters, minimize concentrated stormwater flow, maximize the use of sheet flow through vegetated areas, and maximize the flow length through vegetated areas;

(IV)         areas of concentrated development shall be located in upland areas and away, to the maximum extent practicable, from surface waters and drainageways;

(V)          remainder of tract to remain in vegetated or natural state;

(VI)         area in the vegetated or natural state may be conveyed to a property owners association, a local government for preservation as a park or greenway, a conservation organization, or placed in a permanent conservation or farmland preservation easement;

(VII)       a maintenance agreement for the vegetated or natural area shall be filed with the Register of Deeds; and

(VIII)     cluster development that meets the applicable low density option requirements shall transport stormwater runoff from the development by vegetated conveyances to the maximum extent practicable;

(E)           If local governments choose the high density development option that requires engineered stormwater controls, then they shall assume responsibility for operation and maintenance of the required controls as outlined in Rule .0104 of this Subchapter;

(F)           A minimum 100 foot vegetative buffer shall be required for all new development activities that exceed the low density option requirements as specified in Sub-Item (3)(b)(i)(A) or Sub-Item (3)(b)(ii)(A) of this Rule, otherwise a minimum 30 foot vegetative buffer for development shall be required along all perennial waters indicated on the most recent versions of U.S.G.S. 1:24,000 (7.5 minute) scale topographic maps or as determined by local government studies;

(G)          No new development shall be allowed in the buffer; water dependent structures, or other structures, such as flag poles, signs, and security lights, which result in only de minimus increases in impervious area and public projects such as road crossings and greenways may be allowed where no practicable alternative exists.  These activities shall minimize built‑upon surface area and avoid channelizing stormwater;

(H)          For local governments that do not use the high density option, a maximum of 10 percent of each jurisdiction's portion of the watershed outside of the critical area as delineated on July 1, 1995 may be developed with new development projects and expansions to existing development of up to 70 percent built‑upon surface area (the "10/70 option") in addition to the new development approved in compliance with the appropriate requirements of Sub-Item (3)(b)(i)(A) of this Rule.  For expansions to existing development, the existing built-upon surface area shall not be counted toward the allowed 70 percent built-upon surface area.  A local government having jurisdiction within the watershed may transfer, in whole or in part, its right to the 10/70 option land area to another local government within the watershed upon submittal of a joint resolution for review by the Commission.  When the designated water supply watershed area is composed of public land, such as National Forest land, local governments may count the public land acreage within the designated watershed area outside of the critical area in figuring the acreage allowed under this provision.  Each project shall, to the maximum extent practicable, minimize built‑upon surface area, direct stormwater runoff away from surface waters and incorporate best management practices, as defined in Rule .0202 of this Section, to minimize water quality impacts;

(ii)           Critical Area Nonpoint Source and Stormwater Pollution Control Criteria:

(A)          Low Density Option:  new development activities that require a Sedimenta­tion/Erosion Control Plan in accordance with 15A NCAC 4 established by the North Carolina Sedimentation Control Commission or approved local government programs as delegated by the Sedimentation Control Commission shall be limited to no more than two dwelling units of single family detached development per acre (or 20,000 square foot lot excluding roadway right-of-way), or 24 percent built‑upon area for all other residential and non-residential development; stormwater runoff from the development shall be transported by vegetated conveyances to the maximum extent practicable;

(B)          High Density Option:  if new development density exceeds the low density requirements specified in Sub-Item (3)(b)(ii)(A) of this Rule, engineered stormwater controls shall be used to control runoff from the first inch of rainfall; new residential and non-residential development shall not exceed 50 percent built‑upon area;

(C)          No new permitted sites for land application of residuals or petroleum contaminated soils shall be allowed;

(D)          No new landfills shall be allowed;

(c)           MBAS (Methylene-Blue Active Substances):  not greater than 0.5 mg/l to protect the aesthetic qualities of water supplies and to prevent foaming;

(d)           Odor producing substances contained in sewage, industrial wastes, or other wastes:  only such amounts, whether alone or in combination with other substances or waste, as will not cause taste and odor difficulties in water supplies that cannot be corrected by treatment, impair the palatability of fish, or have a deleterious effect upon any best usage established for waters of this class;

(e)           Chlorinated phenolic compounds:  not greater than 1.0 ug/l to protect water supplies from taste and odor problems due to chlorinated phenols shall be allowed.  Specific phenolic compounds may be given a different limit if it is demonstrated not to cause taste and odor problems and not to be detrimental to other best usage;

(f)            Total hardness shall not exceed 100 mg/l as calcium carbonate (CaCO3 or Ca + Mg);

(g)           Total dissolved solids shall not exceed 500 mg/l;

(h)           Toxic and other deleterious substances:

(i)            Water quality standards (maximum permissible concentrations) to protect human health through water consumption and fish tissue consumption for non‑carcinogens in Class WS‑IV waters:

(A)          Barium:  1.0 mg/l;

(B)          Chloride:  250 mg/l;

(C)          Nickel:  25 ug/l;

(D)          Nitrate nitrogen:  10.0 mg/l;

(E)           2,4‑D:  70 ug/l;

(F)           2,4,5‑TP (Silvex):  10 ug/l; and

(G)          Sulfates:  250 mg/l;

(ii)           Water quality standards (maximum permissible concentrations) to protect human health through water consumption and fish tissue consumption for carcinogens in Class WS‑IV waters:

(A)          Aldrin:  0.05 ng/l;

(B)          Arsenic:  10 ug/l;

(C)          Benzene:  1.19 ug/l;

(D)          Carbon tetrachloride:  0.254 ug/l;

(E)           Chlordane:  0.8 ng/l;

(F)           Chlorinated benzenes:  488 ug/l;

(G)          DDT:  0.2 ng/l;

(H)          Dieldrin:  0.05 ng/l;

(I)            Dioxin:  0.000005 ng/l;

(J)            Heptachlor:  0.08 ng/l;

(K)          Hexachlorobutadiene:  0.44 ug/l;

(L)           Polynuclear aromatic hydrocarbons (total of all PAHs):  2.8 ng/l;

(M)         Tetrachloroethane (1,1,2,2):  0.17 ug/l;

(N)          Tetrachloroethylene:  0.7 ug/l;

(O)          Trichloroethylene:  2.5 ug/l; and

(P)           Vinyl Chloride:  0.025 ug/l.

 

History Note:        Authority G.S. 143‑214.1; 143‑215.3(a)(1);

Eff. February 1, 1986;

Amended Eff. January 1, 2015; May 1, 2007; April 1, 2003; June 1, 1996; October 1, 1995; August 1, 1995; June 1, 1994.